Note: Descriptions are shown in the official language in which they were submitted.
CA 02752322 2016-07-12
SYSTEMS AND METHODS FOR USING ROCK DEBRIS TO INHIBIT THE
INITIATION OR PROPAGATION OF FRACTURES WITHIN A PASSAGEWAY
THROUGH SUBTERRANEAN STRATA
FIELD
[0001] The present invention relates, generally, to systems and methods
usable to
generate and apply lost circulation material (LCM) from rock debris when
performing operations within a passageway through subterranean strata,
including limiting fracture initiation and propagation within subterranean
strata
prior to liner or casing placement and cementation for drilling, casing
drilling,
liner drilling, completions, managed pressure conduit assembly inventions of
the
present inventor, and combinations thereof, beyond conventional casing setting
depths by strengthening the pressure integrity of the well bore.
BACKGROUND
[0002] Embodiments of the present invention relate to the subterranean
creation of lost
circulation material (LCM) from the rock debris inventory within a bored
passageway, used to inhibit fracture initiation or propagation within the
walls of
the passageway through subterranean strata. Apparatuses for employing this
first aspect, may be engaged to drill strings to generate LCM in close
proximity
to newly exposed fracturable strata walls of the bored portion of the
passageway
through subterranean strata, for timely application of said subterranean
generated LCM to said walls.
[0003] Embodiments of rock breaking tools can include: passageway
enlargement tools
(63 of Figures 5 to 7), eccentric milling tools (56 of Figures 8 to 9),
bushing
milling tools (57 of Figures 10 to 12) and rock slurrification tools (65 of
Figures
15 to 39). Usable embodiments of passageway enlargement tools and eccentric
milling tools are dependent upon the drilling or managed pressure conduit
assemblies (49 of Figures 45 to 47), as disclosed in U.S. Patent 8,387,693,
that
are selected for use. The embodiments of said bushing milling tools represent
significant improvements to similar conventional tools described in U.S.
Patent
3,982,594. Embodiments relating to rock slurrification tools (65 of Figures 15
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to 39) represent significant improvements to conventional above ground
technology, described in U.S. Patent 4,090,673, placed within a drill string
to
generate LCM from rock debris in a subterranean environment. The
embodiments relating to said rock slurrification tools break rock debris or
other
breakable materials placed in a slurry through impact with a rotating
impellor, or
through centrifugally accelerating said rock debris or added material to
impact a
relatively stationary or opposite rotational surface.
[0004] Embodiments of the rock breaking tools further use rock
slurrification and
milling of a rock dcbris inventory generated from a drill bit or bore hole
opener
to generate LCM, while conventional methods rely on surface addition of LCM
with an inherent time lag between detection of subterranean fractures through
loss of circulated fluid slurry and subsequent addition of LCM. Embodiments of
the present invention inhibit the initiation or propagation of strata
fractures by
generating LCM from a rock debris inventory urged through a bored
passageway by circulated slurry coating the strata wall of said passageway,
before initiation or significant propagation of fractures occur.
[0005] Due to its relatively inelastic nature, rock has a high propensity
to fracture
during boring and pressurized slurry circulation. With the timely application
of
LCM, embodiments of the present invention may be used to target deeper
subterranean formations prior to lining a strata passageway with protective
casing, by improving the differential pressure barrier, known as filter cake,
between subterranean strata and circulated slurry, by urging lost circulation
material into pore spaces, fractures or small cracks in said wall coated with
circulated slurry in a timely manner to reduce the propensity of fracture
initiation and propagation. Packing LCM within the filter cake, covering the
pore spaces of whole rock, inhibits the initiation of fractures by improving
the
differential pressure bearing nature of said filter cake. Various methods for
limiting initiation and propagation of fractures within strata exist and are
described in U.S. Patent 5,207,282.
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[0006] Embodiments of the present invention, including rock breaking tools
(56, 57, 63,
65), are usable with slurry passageway tools (58 of Figures 45 to 47) and
managed pressure conduit assemblies (49 of Figures 45 to 47) of the present
inventor, that use mechanical and pressurized application of subterranean
generated LCM to supplement and/or replace surface added LCM to strata pore
and fracture spaces, further re-enforcing said filter cake's differential
pressure
bearing capability to further inhibit the initiation or propagation of
fractures with
the timely application and packing of said LCM, referred to by experts in the
art
as well bore stress cage strengthening. Conventional methods, generally,
require that boring be stopped to perform stress cage strengthening of the
well
bores, while embodiments of the present invention may be used to continuously
generate, apply, and pack LCM, via impacting surfaces, into the wall of the
well
bore, for strengthening the well bore during boring, circulation and/or
rotation of
a conduit string carrying said embodiments.
[0007] Embodiments of the present invention include rock breaking tools
(56, 57, 63,
65) that can be usable with conventional drilling strings or casing drilling
and
liner drilling strings, which are used for placement of a protective lining
within
subterranean strata, without requiring removal of the drill string. Once a
desired
subterranean strata bore depth is achieved, all or part of the rock breaking
tool or
managed pressure conduit assembly (49 of Figures 45 to 47) can detach from
one or more outer concentric strings and engage to the passageway through
subterranean strata. The rock breaking tools (56, 57, 63, 65), of the present
invention, prior to removal, can be used to reduce the propensity of fracture
initiation and propagation until the subterranean strata is isolated with the
protective lining. This undertaking removes the risks of first extracting a
drilling string and subsequently urging a liner, casing, completion or other
protective lining string axially downward within the passageway through
subterranean strata, during which time the ability to address subterranean
hazards is limited.
[0008] Liner drilling is similar to casing drilling with the distinction of
having a cross
over apparatus to a drilling string at its upper end. As said cross over
apparatus
is generally not disposed within the subterranean strata and has little effect
on
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annular velocities and pressures experienced by the strata bore, liner
drilling and
casing drilling are referred to synonymously throughout the remainder of the
description.
100091 Additionally, where the large diameter of prior casing drilling
apparatus provide
the benefit of a slurry smear effect, generally inapplicable to smaller
diameter
drilling strings, the addition of rock breaking tools (56, 57, 63, 65)
embodiments
and the managed pressure conduit assembly (49 of Figures 45 to 47) also
emulate said smear effect without requiring higher annular velocities and
frictional losses associated with conventional casing drilling. This is done
by
generation of LCM against or adjacent to the strata wall to pack or pressure
inject LCM, into fractures or the filter cake, with contact and by directing
an
internal annular passageway flow in the same axial direction as circulated
fluid
in the annular passageway between strata and the drill string, thus increasing
flow capacity and decreasing velocity and associated pressure loss in the
direction of annular flow.
[000101 Embodiments of the present invention are usable independently or
combined
with conventional drilling or casing drilling strings, or may be incorporated
into
inventions, of the present inventor, into a single tool (49 of Figures 45 to
47)
system having a plurality of conduit strings with slurry passageway tools (58
of
Figures 45 to 47), multi-function tools controlling said slurry passageway
tools,
and subterranean LCM generation tools (56, 57, 63, 65 of Figures 5 to 39) to
realize the benefits of targeting subterranean depths, that are deeper than
those
currently possible using conventional technology.
[000111 A need exists for systems and methods for increasing available
amounts of LCM
for timely application to subterranean strata to subsequently reduce the
propensity of strata fracture initiation or propagation.
[000121 Significant hazards and costs exist for unacceptable drilling fluid
losses
associated with existing technology within fracture prone strata that, when
multiplied by the number of passageways and the placed protective linings
required to prevent such drilling fluid loses, it represents a significant
cost of
operations.
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[00013] A need exists for systems and methods of creating LCM that are
engagable with
drill strings, protective liners, casings and completion equipment placed
within
subterranean strata without encountering unacceptable losses or the need to
remove a drill string for casing drilling operations.
[00014] A need exists for systems and methods generally applicable across
subterranean
strata, susceptible to fracture, to reach deeper depths than is currently the
practice or realistically achievable with existing technology prior to
placement
of protective drilling and completion linings.
[00015] The present invention meets these needs.
SUMMARY
[00016] Embodiments described herein relate to systems and methods for
providing and
using lost circulation material (LCM) generated from rock debris to inhibit
initiation and/or propagation of strata fractures. One or more boring tools
can
be provided in communication with a conduit string, through a fracturable
region of a subterranean passageway, extending downward from an outermost
protective conduit string that lines the upper end of the subterranean
passageway.
[00017] During operation of the one or more boring tools, rock debris is
produced, which
is circulated in a slurry within the subterranean passageway, such as through
a
contorted pathway of reduced size capacity for changing particle velocity,
thereby increasing the propensity to repeatedly engage and break larger
particles
into smaller particles. One or more apparatus can be used to contact the rock
debris, e.g. with blades that extend radially outward eccentrically,
vertically,
and/or at an inclination, to impel the debris toward impact surfaces of a
surrounding tool or strata wall, which can include a smooth surface, a stepped
profile, a series of irregular impact surfaces with projections extending
radially
inward, or combinations thereof. The particle size of the rock debris is
thereby
reduced as it is urged axially upward by the circulated fluid slurry to coat
the
bored strata wall for inhibiting initiation and/or propagation of strata
fractures,
which can increase the pressure bearing capacity of the coated, fracturable
CA 02752322 2014-12-17
region. Engagement of the particles with blades or similar members aids
carriage of the particles within the slurry and/or application to the strata
wall.
Generally, the particles can be reduced to a size ranging from 250 microns to
600 microns.
[00018] Embodiments, engaged to a conduit string can rotate during use and
can include
one or more members forming a system for LCM generation and application,
e.g. rock-slurrification, grinding, and rock-breaking tools that project
outwardly
therefrom to grind the rock debris or LCM against the strata wall. Such rock
grinding/breaking tools can include one or a stack of eccentric milling
bushings,
slurrification pumps, thrust bearings, impact surfaces, or combinations
thereof
Eccentric milling bushings can become successively angularly offset during
rotation of the conduit string and/or contact with rock debris. Multiple
embodiments can also include an outer conduit string that rotates, causing an
eccentric blade rock-grinding/breaking tool with impact surface projections to
grind the rock debris against the wall of the passageway. In a further
embodiment, axial movement between the conduit strings can cause extension
or retraction of impact surface projections.
BRIEF DESCRIPTION OF THE DRAWINGS
[00019] In the detailed description of various embodiments of the present
invention
presented below, reference is made to the accompanying drawings, in which:
[00020] Figures 1 to 4 illustrate prior art methods for determining the
depth at which a
protective casing must be placed in the subterranean strata, explained in
terms of
the fracture gradient of subterranean strata and required slurry density to
prevent
fracture initiation and propagation, including prior art methods by which said
fracture initiation and propagation may be explained and controlled.
[00021] Figures 5 to 7 depict an embodiment of a bore enlargement tool for
enlarging a
subterranean bore with two or more stages of extendable and retractable
cutters.
[00022] Figures 8 to 9 show an embodiment of a rock milling tool having a
fixed
structure for milling protrusions from the wall of a strata passageway and
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crushing rock particles carried with the fluid slurry against a strata
passageway
wall.
[00023] Figures 10 to 12 illustrate an embodiment of a bushing milling tool
having a
plurality of eccentric rotatable structures for milling protrusions from the
wall of
a strata passageway trapping and crushing rock particles carried with the
fluid
slurry against the wall of said strata passageway.
[00024] Figures 13 to 14 show a prior art apparatus for centrifugally
breaking rock
particles.
[00025] Figures 15 and Figures 18 to 22 illustrate an embodiment of a rock
slurrification
tool wherein the wall of the passageway through subterranean strata is engaged
with a wall of said tool, having various embodiments, wherein an internal
additional wall, disposed within said wall engaged with strata, is rotated
relative
to an internal impeller secured to the internal rotating conduit string, and
arranged in use to accelerate, impact and break rock debris pumped through the
internal cavity of said tool after which broken rock debris is pumped out of
said
internal cavity.
[00026] Figures 16 to 17 show two examples of impact surfaces that may be
engaged to
an impacting surface to aid breaking or cutting of rock.
[00027] Figures 23 to 25 illustrate two embodiments of rock slurrification
tools that may
be engaged with a single wall conduit string or dual walled conduit string
respectively to create LCM by pumping rock debris contained in slurry through
the central cavity of said tools which impact and centrifugally accelerate
denser
rock debris via an impeller to aid breakage of said rock debris.
[00028] Figures 26 to 31 depict member parts of an embodiment of a rock
slurrification
tool in stages of engaging said member parts of said tool, wherein parts are
engaged sequentially from Figure 26 to Figure 30, with the resulting assembly
show in Figure 30 sized for engagement within the impact wall of Figure 31.
[00029] Figure 32 illustrates an embodiment of the present invention rock
slurrification
tool comprised of the member parts of Figures 26 to 31 wherein the impact wall
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of Figure 31 is disposed about the internal member parts of Figure 30 with
rotary conduit connections and thrust bearing surfaces engaged to both ends
for
engagement to a conduit drill string disposed within subterranean strata.
[00030] Figures 33 to 34 depict embodiments of member parts of a rock
slurrification
tool that can be combined with the rock slurrification tool of Figure 32,
wherein
the tool of Figure 33 may be engaged with a single wall conduit drill string
and
the tool of Figure 34 may be engaged with a dual walled conduit string having
an outer conduit string engaged to the ends of the member of Figure 34, and
wherein the tool of Figure 32 can be retrieved with the internal string.
[00031] Figures 35 to 39 illustrate of the tool of Figure 32 engaged with
the member part
of Figure 34 to create a rock slurrification tool for a rotary single walled
conduit
string.
[00032] Figures 40 to 44 depict prior art examples of drilling and casing
drilling, which
identify locations where rock breaking tools of the present invention are
applicable.
[00033] Figures 45 to 47 illustrate two embodiments of a nested conduit
string, wherein
the lower portion of the string shown in Figure 45 can be combined with either
of the two upper portions of the string shown in Figures 46 and 47.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[00034] Before explaining selected embodiments of the present invention in
detail, it is
to be understood that the present invention is not limited to the particular
embodiments described herein and that the present invention can be practiced
or
carried out in various ways.
[00035] The present invention relates, generally, to timely generation and
application of
lost circulation material (LCM) from rock debris for deposition within a
fracture
and/or barrier known as filter cake, that can be engaged to the strata wall to
differentially pressure seal strata pore spaces and fractures, thus inhibiting
initiation or propagation of fractures within strata.
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[00036] Referring now to Figure 1, an isometric view of generally accepted
prior art
graphs, which are superimposed over a subterranean strata column with two
bore arrangements relating subterranean depths to slurry densities and
equivalent pore and fracture gradient pressures of subterranean strata are
shown.
The graphs show that fluid density (3), increasable with the effective
circulating
fluid slurry density in excess of the subterranean strata pore pressure (1),
must
be maintained to prevent ingress of unwanted subterranean substances into said
circulated fluid slurry and/or pressured caving of rock from the walls of the
strata passageway.
[00037] Figure 1 further shows that drilling fluid density (3) must be
between the
subterranean strata fracture gradient pressure (2) and the subterranean pore
pressure (1) to prevent initiating fractures or losing circulated fluid
slurry,
respectively, including influxes of formation fluids or gases and/or caving of
rock from the strata wall.
[00038] In many prior art applications the drilling fluid density (3) must
be maintained
within acceptable bounds (1 and 2), until a protective lining (3A) is set, to
allow
a subsequent increase in slurry density (3) once the protective lining is set,
to
prevent influxes or fluid slurry losses if the density (3) is less than the
subterranean strata pore pressure or greater than the fracture gradient (2),
where
initiation of influxes or initiation and propagation of strata fractures
occurs,
respectively. After which, the process can be repeated and additional
protective
linings (3B and 3C) can be set until reaching a final depth.
[00039] The present invention uses embodiments (56A-56C, 57A-57B, 63A-63C,
65A-
65J) of rock breaking tools (56, 57, 63, 65 of Figures 5 to 39), to increase
the
fracture gradient pressure (2) to a higher gradient (6) by imbedding LCM in
the
filter cake and existing fractures, known as well bore stress cage
strengthening.
The packing of fractures and filter cake increases the fracture gradient and
differentially pressure seals pore and facture spaces, within the strata,
allowing
the effective circulating density to vary between new boundaries (1 and 6)
before protective linings are set (4B), to prevent strata fracture initiation
and
propagation to potentially remove the need for a protective lining (3B or 3C).
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[00040] As the LCM carrying capacity of fluid slurries is limited,
subterranean
generation of LCM can replace or supplement surface additions of LCM. This
allows additional smaller particle size LCM to be added at the surface and
increases the total amount of LCM available for well bore stress cage
strengthening.
[00041] By increasing the fracture gradient pressure (from 2 to 6) with
well bore stress
cage strengthening, it is possible to target a new depth by increasing fluid
slurry
density (4) used within the subterranean strata without initiating or
propagating
fractures prior to placement of a deeper protective lining (4B), which
potentially
saves time and expense. In the example of Figure 1, at the increased fracture
gradient pressure (6), one fewer protective lining or casing string (4A, 4B)
was
used to reach final depth, rather than the lining or casing strings (3A, 3B,
3C)
used at the lower fracture gradient pressure (2), thus saving the time and
cost of
casing strings or unacceptable fluid slurry losses.
[00042] If the new target depth were attempted using conventional drilling
methods and
apparatus, drilling fluid slurry would fracture strata and be lost to said
fractures
when the drilling fluid effective circulating density (4) exceeds the fracture
gradient (2), with various combinations of density and depth comprising the
lost
circulation area (5) of Figure 1.
[00043] Referring now to Figure 2 an isometric view of a cube of
subterranean strata is
shown. The Figure illustrates a prior art model of the relationship between
subterranean fractures between a stronger subterranean strata formation (7),
overlying a weaker and fractured subterranean strata formation (8); overlying
a
stronger subterranean strata formation (9), wherein a wall of a fracturable
passageway (17) exists through the subterranean strata formations.
[00044] Referring now to Figures 2 and 3, forces acting on the model of
Figure 2 and the
weaker fractured formation (8), shown as an isometric view in Figure 3,
includes significant overburden pressure (10 of Figure 2) caused by the weight
of rock above, and include forces acting in the maximum horizontal stress
plane
(11, 12 and 13 of Figure 2 and 20 of Figure 3), and forces acting in the
minimum horizontal stress plane (14, 15 and 16 of Figure 2 and 21 of Figure
3).
CA 02752322 2014-12-17
[00045] Resistance to fracture in the maximum horizontal stress plane
increases with
depth, but is reduced by weaker formations. In this example, the drilling
fluid
effective circulating density (ECD), shown as an opposing force (13), is less
than the stronger formations (7 and 9) resisting force (11), but in excess of
the
resisting force (12) of the weaker formation (8) to resist said force, and a
fracture (18) initiates and/or propagates as a result.
[00046] Resistance to fracture in the minimum horizontal stress plane also
increases with
depth, but can be reduced by weaker formations with the drilling fluid
effective
circulating density (ECD) equal to that in the maximum horizontal stress plane
(13), and is shown as an opposing force (16), that is less than the stronger
formations (7 and 9), but in excess of the resisting force (15) of the weaker
formation (8), and a fracture (18) initiates and/or propagates to the maximum
stress plane as a result.
[00047] Referring now to Figure 3, due to the relatively inelastic nature
of most
subterranean rock, small subterranean horizontal fractures (23) generally form
in
the maximum horizontal stress plane. This may be visualized as hoop stresses
(22) propagating from the maximum (20) to minimum (21) horizontal stress
planes, creating a small fracture (23) on a wall of the fracturable passageway
(17) (i.e. a bore).
[00048] If the horizontal stress forces resisting fracture propagation (12
and 15 of Figure
2) are less than the pressure exerted (13 and 16 of Figure 2) by the effective
or
equivalent circulating density (ECD) of circulated fluid slurry or static
hydrostatic pressure of static fluid slurry (3 of Figure 1), the fracture (23)
will
propagate (24), with the maximum horizontal stress plane hoop stresses (22)
aiding said propagation (24) as they seek the minimum horizontal stress plane
(21), shown as dashed convex arrows acting at the edges of said fracture and
point of fracture propagation (25).
[00049] Referring now to Figure 4, an isometric view of two horizontal
fractures across
a wall of a fracturable passageway (17) through subterranean strata coated
with
a filter cake (26) is shown. Rock debris (27) of sizes greater than that of an
LCM particle size distribution cannot be sufficiently packed within a fracture
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CA 02752322 2014-12-17
and create large pore spaces through which pressure may pass (28) to the point
of fracture propagation (25), allowing further propagation of fractures.
Fracture
propagation can be inhibited by packing LCM sized particles (29) within a
fracture (18) and allowing the filter cake (26) to bridge and seal between the
LCM particles, to differentially pressure seal the point of facture
propagation
(25) from hydrostatic pressure or higher ECD pressures and further
propagation.
[00050] Embodiments (56A-56E, 57A-57E, 63A-63C, 65A-65L) of rock breaking
tools
(56, 57, 63, 65 of Figures 5 to 39) may be used to generate LCM proximate to
strata pore spaces and fractures (18) to replace or supplement surface added
LCM, while embodiments (58A-58Z) of slurry passageway tools (58 of Figures
45 to 47) may be used to reduce ECD and associated fluid slurry loses until
sufficient LCM is placed in a fracture. In addition, rock breaking tools can
be
used to pressure inject or pressure compact said LCM with higher ECD
occurring through the restricted or tortuous potentially rotating annular
passageway formed by engagement of the rock breaking tool with the strata
wall, wherein said engagement can mechanically smear and/or compact filter
cake and LCM against strata wall pore and fracture spaces to inhibit strata
fracture initiation or propagation.
[00051] Embodiments of the present invention treat fractures in the
horizontal plane (18
of Figures 2 to 4) and those not in the horizontal plane (19 of Figure 2)
equally,
filling the fractures either with LCM generated downhole, surface added LCM,
or combinations thereof, with mechanical application through rock breaking
tool
engagement with the strata wall, which can be combined with selective
manipulation of the effective circulating density, to manage horizontal
fracture
initiation and seal strata pore spaces and fractures with filter cake and LCM
in a
timely manner to prevent further initiation or propagation.
[00052] Referring now to Figures 5 to 39, embodiments of rock breaking
tools usable to
generate LCM downhole are depicted, and include: milling bore enlargement
tools (63 of Figures 5 to 7), eccentric milling tools (56 of Figures 8 to 9),
eccentric bushing milling tools (57 of Figures 10 to 12), rock slurrification
tools
(65 of Figures 15 to 39) and combinations of said enlargement, milling and
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slurrification tools in Figures 45 to 47.
[00053] Prevalent practice regards LCM to include particles ranging in size
from 250
microns to 600 microns, or visually between the size of fine and coarse sand,
supplied in sufficient amounts to inhibit fracture initiation and fracture
propagation. For example, if PDC cutter technology is used to produce
relatively consistent particle sizes for a majority of rock types, and the
probability of breaking rock particles is relative to the size of rock debris
generated by said PDC technology, then approximately 4 to 5 breakages of rock
debris will result in more than half of the rock debris particle inventory
urged
out of a bored strata passageway by circulated fluid slurry to be converted
into
particles of LCM size. Gravity and slip velocities through circulated slurry
in
vertical and inclined bores combined with rotating tortuous pathways and
increased difficulty of larger particles passing rock breaking embodiments of
the
present invention provide sufficient residence time for larger particles
within the
rock debris inventory to be broken approximately 4 to 5 times before becoming
efficiently sized for use by circulated slurry.
[00054] Rock breaking tools (56, 57, 63 or 65), used for subterranean LCM
generation
can improve the frictional nature of the wall of the passageway through
subterranean strata with a polishing-like action, for reducing frictional
resistance, torque and drag while impacting filter cake and LCM into strata
pore
spaces and fractures.
[00055] When rock debris from boring is broken into LCM size particles and
applied to
the filter cake, strata pore spaces and fractures of the strata passageway,
the
fracture initiation and propagation can be inhibited and the amount of rock
debris that must be extracted from the bore is reduced, such that the debris
is
easier to carry and place due to its reduced particle size and associated
density.
[00056] While conventional methods include the surface addition of larger
particles of
LCM, such as crushed nut shells and other hard particles, these particles are
generally lost during processing when returned drilling slurry passes over
shale
shakers. Conversely, embodiments of the present invention continually replace
said larger particles, allowing smaller particles, which are more easily
carried
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and less likely to be lost during processing to remain within the drilling
slurry
for reducing costs of operation by eliminating the need for continual surface
addition of larger particles.
[00057] The mix of particle sizes of varying quantities is usable for
packing subterranean
fractures to create an effective differential pressure seal when combined with
a
filter cake. Where large particles are lost during processing of slurry,
smaller
particles are generally retained if drilling centrifuges are avoided. The
combination of smaller particle size LCM added at surface with larger particle
size LCM generated down hole can be used to increase levels of available LCM
and to decrease the number of breakages and/or rock breaking tools needed to
generate sufficient LCM levels.
[00058] Embodiments of the present invention thereby reduce the need to
continually
add LCM particles and reduce the time between fracture propagation and
treatment due to the continual downhole creation of LCM in the vicinity of
fractures while urging the passageway through subterranean strata axially
downwards. The combination of filter cake and LCM strengthens the well bore
by sealing the point of fracture propagation. Conventional drilling
apparatuses
do not address the issue of creation or timely application of LCM, or only
incidentally and significantly after the point of fracture propagation, with a
large
fraction of smaller sized rock debris seen at the shale shakers generated
through
incidental impacts within the protective conduit string lining (51V of Figures
46-47) where it is no longer needed.
[00059] Generally, rock breaking tools (56, 57, 63 or 65) can have an upper
end engaged
with the lower end of a passageway from the discharge of one or more slurry
pumps, and a lower end engaged with the upper end of one or more
passageways for discharging pumped slurry through one or more rotary boring
apparatuses.
[00060] The depicted embodiments of rock breaking tools are shown having
one or more
surrounding or additional walls (51U), including eccentric surfaces of the
blades
(56A-56C) and/or bushing (124) and/or thrust bearing (125), which can
surround a wall of a first conduit (50) with upper and lower ends engaging
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conduits of a conduit drilling string having an internal passageway (53) that
urges slurry in an axially downward direction to said boring apparatus. Said
one
or more surrounding walls can engage rock debris and/or the wall of the bored
passageway where a blade (56A-56E, 61, 61A-61C, 111A-111H) or impeller
(111), protrusion, or similar member of the rock breaking tool crushes rock
debris against an impact wall for subsequent pressurized application or
impacts
the strata wall to polish said strata wall and to impact LCM sized particles
into
strata pore and facture spaces.
[00061] The surrounding wall of said rock breaking tools can urge slurry
against a wall
and/or through a smaller passage upward, creating a tortuous path and pressure
change across said tool, inhibiting the passage of larger rock debris for
further
crushing, milling and/or pressure injecting LCM against a fracturable region
with said pressure change.
[00062] Embodiments of the rock slurrification tool (65) can include an
inner cavity
between walls of the conduit strings (50, 51, 51A-51U) wherein an impeller or
blade is used to pump slurry from the annular passageway, located between said
tool and the strata bore wall, into the internal cavity, where larger
particles are
impacted and broken centrifugally. Then pumped out of the internal cavity into
the annular passageway.
[00063] Referring now to Figure 5 and Figure 6, an isometric view of an
embodiment
(63A) of a rock breaking tool and a milling bore hole enlargement tool (63),
for
enlarging bores within a subterranean rock formation in two or more stages is
shown. Figure 5 depicts a telescopically elongated subassembly with cutters
retracted. Figure 6 depicts telescopically deployed (68) cutter stages that
are
extended (71 of Figure 6) as a result of said deployment. Blades (61)
comprising first stage cutters (61A), second stage cutters (61B) and third
stage
cutters (61C) with impact surfaces (123) embodiment (123D), which can include
PDC technology, are shown telescopically deployed (68) in an outward
orientation (71 of Figure 6). The first conduit string (50) carries slurry
within its
internal passageway (53) and actuates said cutters, secured to a wall (51E)
that
can be engaged with and through the wall (51D of Figure 7) of an additional
CA 02752322 2014-12-17
conduit string (51 of Figure 7). Rotation around the tool's axial centerline
(67)
engages said first and subsequent staged cutters with the strata wall to cut
rock
and enlarge the passageway through subterranean strata. Having two or more
stages of cutters reduces the particle size of rock debris and creates a step
wise
tortuous path, increasing the propensity to generate LCM and reducing the
number of additional breakages required to generate LCM within the
passageway through subterranean strata.
[00064] Referring now to Figure 7, an isometric view of an embodiment of
the wall
(51D) of the additional conduit string (51) of a milling bore enlargement tool
with orifices (59) and receptacles (89), through which staged (61A, 61B, 61C
of
Figures 5 and 6) blade (61) cutters can be extended and retracted, is shown.
The
orifices or receptacles provide lateral support for the staged cutters when
rotated. The upper end of the wall of the additional conduit string (51) can
be
engaged with an additional wall of a slurry passageway tool (58 of Figures 45
to
47) or managed pressure conduit assembly (49 of Figures 45 to 47) to enlarge
the bore for passage of additional tools.
[00065] Referring now to Figure 8, an isometric view of an embodiment (56B)
of an
eccentric rock milling tool (56) is shown. The tool (56) includes an eccentric
blade (56B) and impact surfaces (123) embodiment (123E), such as hard metal
inserts or PDC cutters, which form an integral part or wall (51F) of an
additional
conduit string (51) disposed about a first conduit string (50). The upper and
lower ends of the rock milling tool can be placed between conduits of a dual
walled string or managed pressure conduit assembly (49 of Figures 45 to 47)
for
urging the breakage of a rock inventory by trapping and crushing rock against
the wall of the passageway, or by engaging rock projections from the strata
wall
and urging the creation of LCM sized particles from rock debris.
[00066] Referring now to Figure 9, a plan cross sectional view of the rock
breaking tool
of Figure 8 is shown. The Figure illustrates the eccentric blade (56B) having
a
radius (R2) and offset (D) from the central axis of the tool and relative to
the
internal diameter (ID) and radius (R) of the nested additional wall (51), with
impact surfaces (123), such as PDC cutters or hard metal inserts engaged to
said
16
CA 02752322 2014-12-17
blade. In use, the tool can be disposed between conduits of a dual walled
string
or managed pressure conduit assembly embodiment (49 of Figures 45 to 47).
[00067] Referring now to Figure 10, an isometric view of an embodiment
(57A) of a
bushing milling tool (57) is depicted. The tool (57) includes a plurality of
stacked additional rotating walls or bushings (124) having eccentric surfaces
engaged with hard freewheeling (1231) impact surfaces (123) and intermediate
thrust bearings (125 of Figure 12). The depicted bushing milling tool has
milling
bushings with eccentric surfaces (124) disposed about a nested wall (51G) of
an
additional conduit string (51) and the first conduit string (50) for use with
a
managed pressure conduit assembly (49 of Figures 45 to 47). The plurality of
rotating eccentric milling bushings (124), rotate freely and are disposed
about a
dual wall string (49 of Figures 46 to 47), having connections (72) to conduit
string disposed within the passageway to urge breakage of rock debris into LCM
sized particles.
[00068] Referring now to Figure 11, a plan view of an embodiment (57B) of a
bushing
milling tool (57), disposed within the passageway through subterranean strata
(52), with section line AA-AA associated with Figure 12, is shown. The free
rotating surfaces of the eccentric milling bushings (124) create a tortuous
slurry
path within the passageway through subterranean strata (52), such that rock
debris in the first annular passage (55 of Figure 15) is trapped and crushed
between said bushing milling tool (57) and wall of the passageway through
subterranean strata (52), urging rotation of individual bushings and further
urging the breakage of rock into LCM sized particles.
[00069] Referring now to Figure 12, a cross sectional elevation view of the
bushing
milling tool (57) of Figure 11 is shown as Section AA-AA, taken along line AA-
AA of Figure 11, with the passageway through subterranean strata removed to
show the tortuous slurry path created by the tool. Frictional string rotation
on
rock debris trapped next to the bushing's non-eccentric surface urges the
eccentric surface to rotate, and the rock debris can be further trapped by
eccentric bushings (124) axially above, which catch and crush larger particles
while smaller particles travel around said bushings tortuous path and are
carried,
17
CA 02752322 2014-12-17
by circulated slurry, about a single wall drill string (33 of Figure 40 to 41
and 40
of Figure 42). A thrust bearing arrangement (125) is also shown separating the
eccentric bushings (124) of the bushing milling tool (57).
[00070] Referring now to Figure 13, a plan view of a prior art centrifugal
rock crusher
with a section line AB-AB associated with Figure 14 is shown. The rock
crusher hurls rocks (126) against an impact surface by supplying said rock
through a central feed or intake passageway (127) and engaging said rock with
a
rotating impellor.
[00071] Referring now to Figure 14, a cross-sectional isometric view of the
prior art
centrifugal rock crusher taken along line AB-AB of Figure 13 is shown. Figure
14 depicts a central passageway (127) that feeds rock (126) to an impellor
(111),
which rotates in the depicted direction (71A). The impellor (111) hurls rock
against an impact surface (128), such that the engagement with the impellor
(111) and/or surface (128) breaks the rock, which is then expelled through an
exit passageway (129).
[00072] Referring now to Figures 15 to 39, various embodiments (65A-65F) of
rock
slurrification tools (65), that urge one or more impeller blades (111A-111H)
and/or eccentric blades (56A, 56C), which can be secured to the first wall
(50)
or additional walls (51A-51U) and engaged with the strata wall (52), are
shown.
The first wall (50) is rotated for urging one or more additional impeller
blades
(111A-111C), wall engagement blades (111D-111H) and/or eccentric blades
(56A, 56C), which are secured to either said first wall (50) or an additional
wall
(51B, 51K, 51M) disposed about said first wall and driven by a gearing
arrangement between said first wall (50) and an additional wall (51A, 51C-51J,
51N-51U) engaged to the strata wall with wall securing blades (111D-111H).
The additional wall (51B, 51K, 51M), that is disposed between the first wall
(50) and additional wall (51A, 51C-51J, 51N-51U) engaged with the strata wall
can rotate via a geared arrangement in the same or opposite rotational sense
and
can have secured blades (56A, 56C, 111, 111A-111C) for impelling rock debris,
or to act as an impact surface for impelled rock debris. Engagement of higher
density rock debris particles with impeller blades (111, 111A-111C) or
eccentric
18
CA 02752322 2014-12-17
blades (56A) impacts and breaks and/or centrifugally accelerates said higher
density elements toward impact walls and impeller blades.
[00073] Relative rotational speeds and directional senses between impeller
blades
(111A-111C), wall engagement blades (111D-111H), eccentric blades (56A-
56C) and/or impact walls (50, 51, 51A-51U, 52) can be varied to increase
breakage rates and/or to prevent fouling of tools with compacted rock debris.
[00074] Referring now to Figure 15, a cross sectional plan slice view, with
dashed lines
showing hidden surfaces, of an embodiment (65A) of the rock slurrification
tool
(65) is shown. The Figure depicts slurry being pumped axially downward
through the internal passageway (53) and returned through the first annular
passageway (55) between the rock slurrification tool (65) and the passageway
through subterranean strata (52). The rock slurrification tool (65) acts as a
centrifugal pump taking slurry from said first annular passageway (55),
through
an intake passageway (127), and into an additional annular passageway (54)
where a blade of the impeller (111) impacts and urges the breakage and/or
acceleration of dense rock debris particles (126) toward an impact wall (51H)
having impact surfaces (123) for breaking said accelerated dense rock debris
particles (126). Engagements between the blades of the impeller (111), rock
debris particles (126) and impact walls (51H) continue until said slurry is
expelled through an exit passageway (129). The impact wall (51H) has a spline
arrangement (91) for rotating the eccentric bladed wall (56A) and may be
removed if the eccentric wall forms part of the protective lining of a dual
wall
string (51) or managed pressure conduit assembly (49 of Figures 45 to 47).
[00075] In various embodiments of the invention, the additional inner wall
(51B) of
Figures 15 and 21-22, 51K of Figure 23, 51M of Figures 24-25), secured blades
of an impellor (111), adjustable diameter blades (e.g., 11111 of Figure 23)
and/or
expulsion impellor blades (111A, 111B and 111C of Figures 23-24 and 32), can
be rotated through a connection to the rotated first conduit string (50), to a
positive displacement fluid motor that can be disposed axially above or below
and secured to said additional wall, to a gearing arrangement between a blade
of
impellor (111) or an additional wall (51A of Figures 18 and 21-22, 51J of
Figure
19
CA 02752322 2014-12-17
23, 51M of Figures 24-25, 51U of Figures 27-29) and another wall engaged to
the strata wall with a wall engagement blade (111D of Figures 18 and 21, 111G
of Figure 22, 111H of Figure 23 and 111E of Figures 33-39) or eccentric blade
(56A of Figure 15, 56C of Figures 24-25), or combinations thereof. The impact
surface (123) may comprise or be engaged to the additional wall (51H) as shown
in Figure 15, (51R) of Figures 33 and 35-39, and (51T) of Figure 34, that is
shown secured to the strata wall (52). A blade of the impellor (111) and/or
the
additional wall (51B, 51K and 51M) can be rotated within another additional
wall (51A, 51J, 51N) or the lining (51V) that is engaged to the strata wall
(52)
with a wall engagement blade (11D, 111G, 111H and 111E), using a conduit
string (50, 51), a motor, and/or a gearing arrangement, for example, as shown
in
Figures 18 to 25, in the same or opposite directional sense relative to the
first
conduit string (50).
[00076] Referring now to Figures 16 and 17, isometric views of embodiments
(123A,
123B, respectively) of usable shapes of impact surfaces (123) are shown, which
can be engaged to various embodiments of an impact wall (51, 51A-51T), a
blade and/or a bushing, such as that of Figure 15, or cutters of Figures 5 to
12.
The impact surfaces may be constructed from any generally rigid material
usable within a downhole environment, such as hardened steel or PDC
technology. Figure 16 depicts an impact surface (123) having a rounded shape
(123A), while Figure 17 depicts an impact surface (123) having a pyramid shape
(123B). However, it should be noted that impact surfaces (123) having any
shape (e.g. 123A-123H) are usable depending upon the nature of the strata
being
bored or broken.
[00077] Referring now to Figure 18, an isometric view, with a quarter of
the strata wall
removed, showing a slice of a member part of an embodiment (65B) of the rock
slurrification tool (65) of Figure 21 is depicted. The Figure shows the
engagement of vertical blades (111D) having impact surfaces (123) embodiment
(123G) with the wall of the passageway through subterranean strata (52). The
depicted engagement serves to urge the gearing arrangement (130), that can be
secured to the additional wall (51A), to a near stationary state while slurry
can
be urged through the first annular passageway (55) between the rock
CA 02752322 2014-12-17
slurrification tool member part and the strata wall (52). The slurry is urged
at a
higher ECD from the fluid friction of the passageway (55) restriction, caused
by
the blade (111D) engagements with the strata wall (52), to pressure compact
LCM from the slurrification pump discharge exit passageways (129 of Figures
20-21).
[00078] Referring now to Figure 19, an isometric view of a member part of
an
embodiment (65B) of the rock slurrification tool (65) of Figure 21 is shown.
In
Figure 21, a first wall (50), with an internal passageway (53) used for urging
slurry, is rotated (67), and a secured gear (132) and an engaged impeller
(111)
are also rotated (67) in opposition to an additional wall (51B of Figure 20).
[00079] Referring now to Figure 20, an isometric view of a member part of
an
embodiment (65B) of the rock slurrification tool (65) of Figure 21 is
depicted.
The Figure shows an additional wall (51B) with stepwise (123C) impact surface
(123) and a gearing arrangement (131), having an intake passageway (127) at
its
lower end and discharge orifices or discharge exit passageway (129) within its
walls. The additional wall (51B) can be rotatable (71A) to prevent fouling and
to improve the relative speed of impact between a blade of an impeller (111 of
Figure 19), rock debris and the additional wall (51B), further urging the
breakage of rock and increasing the propensity to create LCM sized particles.
[00080] Referring now to Figure 21, an isometric view of an embodiment
(65B) of a
rock slurrification tool (65) constructed by engaged member parts of Figures
18
to 20 is shown. The Figure includes a one-half section of the gearing
arrangements (130) of Figure 18 and a three-quarter section of the additional
wall (51B of Figure 20), illustrating that the relative rotational speed
between
the blade of the impeller (111) and the additional impact wall (51B) may be
increased by use of gearing arrangements (130, 131 and 132) to cause an
opposite directional rotation (67 and 71A) of the blade of the impeller (111)
and
additional wall (51B), thereby increasing the relative impact speed of rock
debris engaging the blade of the impeller (111) and impact surface (123)
embodiment (123C) of the additional wall (51B), further urging the breakage of
rock and increasing the propensity to create LCM sized particles.
21
CA 02752322 2014-12-17
[00081] Referring now to Figure 22, a partial plan view of a gearing
rotational
arrangement of an embodiment (65G) of the rock slurrification tool (65) is
depicted, showing gearing arrangements (130, 131 and 132) for driving a gear
arrangement (132) with a first wall (50) that is rotating (67) another gear
arrangement (130), which is secured to an additional wall (51A) that is
engaged
with a blade (111G) to the wall of the passageway through subterranean strata.
Rotation (71B) of the second gear arrangement (130) causes rotation of a third
gear arrangement (131), which is secured to an additional wall (51B) rotated
within the surrounding additional wall (51A) in a different direction (71A) to
the
first wall rotation (67).
[00082] Referring now to Figure 23, a plan view of an embodiment (65C) of a
rock
slurrification tool (65), having associated line AC-AC, is shown above a cross
sectional isometric view of an embodiment of the rock slurrification tool
(65).
Connectors (72) are shown for engagement of conduits of a single walled drill
string at its upper and lower ends. An adjustable diameter blade (e.g., 111H),
extending through a surrounding additional wall (51J),may be expanded or
retracted by axially moving a wedging sleeve (133), thereby causing
engagement and disengagement of the blade (111H) from strata walls when
conduit string (50) compression is applied and removed, respectively. In use,
engagement to the strata wall by the blade (111H) holds the surrounding
additional wall (51J) to operate gears (130) for rotating the surrounding
additional wall (51K) opposite to the conduit string (50) rotated impellor
(111),
and slurry containing rock debris is taken (127A) from the first annular
passageway between the rock slurrification tool and the strata through an
intake
passageway (127) and slurrified with the opposing blade of the impellor (111)
and surrounding additional wall (51K) rotation and internal (123F) impact
surface (123). Then, the slurry is expelled (129A), from a discharge exit
passageway (129), back to the first annular passageway, after having urged the
breakage of said rock debris into LCM size particles within. A telescoping
splined thrust bearing arrangement (125) is also shown within the rock
slurrification tool for enabling the wedging sleeve (133) to be engaged to the
first wall (50) with the spline driving the lower rotary connection (72) and
22
CA 02752322 2014-12-17
associated apparatus, for example a strata boring bit. An additional expulsion
impellor (111A) is included above gearing (130, 131) driving the rotated inner
additional wall (51K) to aid passage of and prevent fouling of the expulsion
passageway.
[00083] Referring now to Figure 24, a plan view of an embodiment (65D) of a
rock
slurrification tool having associated line AD-AD is shown above a cross
sectional isometric view. Connectors (72) are depicted for engagement with
conduits of a dual walled drill string at its upper and lower ends. An
eccentric
blade (56C) with internal (123F) and external (123H) impact surfaces (123),
can
be engaged with walls within the strata. In use, slurry containing rock debris
is
taken (127A) from the first annular passageway between the rock slurrification
tool and the strata through an intake passageway (127) and expelled (129A),
from a discharge exit passageway (129), back to the first annular passageway,
after having urged the breakage of said rock debris into LCM size particles
within. The depicted embodiment also has intake (127) and expelling (129)
passageways within the eccentric blade (56C) isolated by additional partial
wall
(51C) from slurry passing axially upward (69) through said eccentric blade and
between the inner wall of said eccentric blade and the additional adjacent
wall
(51N) around the additional partial wall (51C) to fluidly communicate between
the additional annular passageways above and below the tool. The internal
slurrification member part may also be removed, leaving the eccentric blade
(56A) and containing wall as a part of the outer dual string wall (51).
[00084] Referring now to Figure 25, a magnified detail view of a portion of
the rock
slurrification tool within line AE of Figure 24 is depicted. The Figure shows
the
intake passageway (127) and flowing arrangement about said intake passageway
of the axially upward flow (69) in the intermediate additional annular
passageway (54) and through the passageway in the eccentric blade (56C). The
additional wall (51C) can be moved axially upward during retrieval of the
internal slurrification member part of the additional wall (51M) leaving the
wall
(51M) and the eccentric blade (56C) secured to the additional lining, thereby
covering and closing the intake (127) and expulsion (129) passageways within
said eccentric blade.
23
CA 02752322 2014-12-17
[00085] Referring now to Figure 26, an isometric view of a member part of
the wall of
the first conduit string (50) subassembly of the rock slurrification tool
shown in
Figures 35 to 39 is depicted, wherein a gear assembly (132A) is engaged to the
first conduit string (50).
[00086] Referring now to Figure 27, an isometric view of an additional wall
(51U),
having a blade of an impeller (111) and gear assembly (131A) thereon, is shown
disposed about the first conduit string (50) subassembly shown in Figure 26.
The depicted additional walls (50, 51U) are member parts of the rock
slurrification tool (65) shown in Figures 35 to 39. The additional wall (51U)
and gear assembly (131A) may rotate independently of the first wall (50) and
gear assembly (132A).
[00087] Referring now to Figure 28, an isometric view of a member gear
arrangement
(130A), engaged with the additional wall (51U) gears (131A) and first conduit
string (50 of Figure 27) gears (123A), subassembly shown in Figure 27 is
depicted. In the Figure, said subassemblies are member parts of the
embodiment (65F) of the rock slurrification tool (65) shown in Figures 35 to
39.
The gear assembly (132A) engaged to the first conduit string (50), is engaged
with and turns the gearing arrangement (130A), which in turn is engaged with
and turns the gear assembly (131A), which is secured to the additional wall
(51U) disposed about the first conduit string (50), to increase the speed at
which
said additional wall and blades of the impeller are rotated.
[00088] Referring now to Figure 29, an isometric view of a gear housing
(134) member
part, that is engaged with the gear arrangement (132A), additional wall (51U)
and first conduit string (50) subassembly shown in Figure 28 is shown. In said
Figure, said subassemblies are member parts of the embodiment of the rock
slurrification tool (65) shown in Figures 35 to 39, and the gear housing
secures
the gearing arrangement (132A).
[00089] Referring now to Figure 30, an isometric view of the intake
passageway (127)
and expulsion passageway (129) member parts are shown engaged to the gear
housing (134), additional wall (51U) and first conduit string (50) subassembly
shown in Figures 28 and 29. In the Figure 29, said subassemblies are member
24
CA 02752322 2014-12-17
parts of the embodiment of the rock slurrification tool (65), shown in Figures
35
to 39. The intake passageway (127) is usable to urge slurry containing rock
debris to impact with the blade of the impellor (111) after which slurry and
broken rock debris are expelled through the expulsion passageway (129) and
returned to the passageway from which they were taken.
[00090] Referring now to Figure 31, an isometric view of an embodiment of
an
additional wall (51Q) having impact surfaces (123) embodiment (123C) for
engagement with the subassembly of Figure 30 is depicted, wherein said
stepwise impact surfaces (123) are used for engaging dense rock debris
particles
impelled within slurry.
[00091] Referring now to Figure 32, an isometric view of an embodiment
(65E) of a
rock slurrification tool (65) is shown, having the external impeller or
eccentric
blades removed. The depicted embodiment includes the member part of Figure
31 disposed about the member parts shown in Figure 30 with conduit connectors
(72) at distal ends of a first conduit wall (50). The addition of the external
impeller bladed arrangement shown in Figure 33 to the depicted embodiment
creates the rock slurrification tool (65) shown in Figures 35 to 39. The rock
slurrification tool (65) can also include thrust bearings (125) and additional
impeller blades (111C) to further urge slurry from the expulsion passageway
(129) and prevent fouling of said passageway.
[00092] Referring now to Figure 33, an isometric view of an additional wall
(51R) with
an intake passageway (127) for suction and a discharge exit passageway (129)
is
shown, having external wall engagement blades (111E) disposed thereon and
associated thrust bearings (125). When assembled with the member part of
Figure 32, the rock slurrification tool (65) of Figures 35 to 39 is created.
[00093] Referring now to Figure 34, an isometric view of an alternate
embodiment of an
additional wall (51T) having intake passageways (127) for suction and
discharge
exit passageways (129), that can be engaged with associated thrust bearings
(125), as depicted in Figure 32 for engagement with dual walled drill strings,
is
depicted. The distal ends of said additional wall (51T) can be engaged with
the
walls of a dual wall string, such as shown in an embodiment of the managed
CA 02752322 2014-12-17
pressure conduit assembly (49 of Figures 45 to 47) with the first walls (50)
of
Figure 32 engaged to the first conduit string walls of the depicted managed
pressure conduit assembly. If an intermediate passageway is required, by-pass
passageways through orifices in the blade (111F) may be present to route an
intermediate annular passageway around the rock slurrification (58) internal
components shown in Figure 32, which can be retrieved with the inner string
after placement of the outer string of said dual wall string.
[00094] Referring now to Figure 35, a plan view of an embodiment (65F) of
the rock
slurrification tool (65) constructed from the member parts shown in Figures 32
and 33, is shown, wherein a section line X-X is included for defining views
depicted in Figures 36 to 39.
[00095] Referring now to Figure 36, a cross sectional elevation view of the
rock
slurrification tool shown in Figure 35 is depicted along line X-X. In the
Figure,
a wall of the first conduit string (50) having thrust bearings (125), is
engaged to
an outermost nested additional wall (51R) having larger intake passageways
(127) and smaller expulsion passageways (129) for slurry and rock debris
intake
and pumped pressurized fluid expulsion, respectively. In addition, a gearing
arrangement (130A) is shown engaged with a gear housing (134 of Figure 38)
that is secured to said outermost additional wall (51R), having wall
engagement
blades (111E) for engagement with the strata wall. The depicted upper and
lower connectors (72) can be engaged with a single walled drill string for
pumping slurry through its internal passageway to be returned between the rock
slurrification tool and the strata wall, carrying rock debris that is urged to
LCM
sized particles by impact of the blades of the impeller (111) and additional
wall
(51Q), after which it is expelled through an expulsion passageway (129) for
immediate pressurized fluid application against the strata wall to reduce the
propensity of initiating or propagating fractures.
[00096] Referring now to Figure 37, an isometric view of the rock
slurrification tool
shown in Figure 36 is depicted, with the inclusion of detail lines Y and Z.
Figure 37 depicts the internal members of the rock slurrification tool,
including
the gearing arrangement (130A) secured to the additional wall (51R) and used
to
26
CA 02752322 2014-12-17
rotate the internal blades of the impeller (111) about the first wall (50).
[00097] Referring now to Figure 38, a magnified isometric view of the
region of the tool
of Figure 37 within detail line Y, is shown. The Figure depicts the upper gear
transmission comprising a gear assembly (132A) secured to the rotated wall of
the first conduit string (50), which transmits rotation to a gearing
arrangement
(130A) within a housing (134), that is shown secured to an outermost
additional
wall (51R) engaged to the strata via external blades of the impeller (111).
Freewheeling gears, disposed about the first conduit wall (50), and gearing
ratios are used to increase the speed of rotation of said gearing arrangement
(130A) to transmit a significantly increased rotational speed to the gear
(131A),
which is secured to an internal impeller blade (111) and additional wall (51U)
disposed and rotating about said internal wall (50). The significantly
increased
rotational speed of the internal impeller blade and its subsequent contact
with
rock debris against near stationary stepped profile impact surfaces (123) of
the
additional wall (51Q), which are engagable to the passageway through
subterranean strata through the outermost wall engagement blades (111E),
significantly increases the creation of LCM sized particles expelled from an
expulsion passageway (129) for engagement with strata wall.
[00098] Referring now to Figure 39, a magnified isometric view of the
region of the tool
of Figure 37 within detail line Z is shown. The Figure depicts the lower gear
transmission housing (134) and suction orifice or intake passageway (127)
arranged to urge slurry to a centralized initial engagement with the blade of
the
impeller (111) to increase the efficiency of centrifugally accelerating rock
debris
toward stepwise (123C) impact surfaces (123).
[00099] Having described embodiments of rock breaking tools, various
embodiments of
these tools can be combined with single or dual walled string arrangements to
facilitate systematic subterranean LCM creation during drilling, lining and/or
completion of subterranean strata.
[000100] Referring now to Figures 40 to 44, cross sectional elevation views
depicting
prior art drilling and prior art casing drilling of subterranean rock
formations are
shown, wherein a derrick (31) is used to hoist a single walled drill string
(33, 40)
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CA 02752322 2014-12-17
(e.g. a drill string), bottom hole assembly (34, 42 to 48), boring tool (47)
and
boring bit (35) through a rotary table (32) to bore through strata (30).
Prevalent
prior art methods use single walled string apparatus to bore passageways in
subterranean strata, while various embodiments described herein are usable
with
single and dual walled strings formed by placing single walled strings within
one or more larger single walled strings to create a string having a plurality
of
walls and associated uses.
[000101] Referring now to Figure 41 and 42, a magnified detail view of the
portion of the
bottom hole assembly (BHA) of Figure 40 defined by line AQ is shown to the
left of Figure 42 depicting an isometric view of a casing drilling
arrangement.
Figure 41 depicts a large diameter BHA with drill collars (34) and a small
diameter single walled drill string axially above, while Figure 42 shows a
single-
walled smaller diameter casing drilling BHA below a larger diameter single
walled drilling string (40) (e.g., a casing drilling string). Figure 42 shows
the
use of a boring tool (47) in communication with a conduit string, where a rock
breaking tool embodiment (63B) is usable. Both depicted arrangements, shown
in Figs. 41 and 42, use single wall strings (30, 40). Embodiments (56D, 56E,
57C, 57D, 63B, 65H, 65J) of rock breaking tools (56, 57, 63 and 65 of Figures
5
to 39) may form part of either the single walled string or bottom hole
assembly.
Application or smearing of LCM generated by these rock breaking tools or
impact of the large diameter of a bottom hole assembly or single walled string
against the strata wall is affected by the smaller annular space between a
larger
effective diameter string or BHA and the strata, compared to that of a smaller
effective diameter string or BHA, where the friction, velocity and pressure
affect
the effective circulating density or ECD of fluid circulated axially upward,
wherein it is significantly higher through a restricted annular passageway
than
that of less restricted annular passageway with equivalent flow rates for
pressurized application of LCM.
10001021 Referring now to Figures 43 and 44, elevation views of a directional
and straight
hole casing drilling arrangement, respectively, are shown, in which Figure 43
depicts a flexible or bent connection (44) and bottom hole assembly (43),
attached (42) to a single walled string (40) prior to boring a directional
hole.
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Figure 44 depicts a bottom hole assembly usable when boring a straight hole
section. The bottom hole assembly (46) of Figure 43 below the flexible or bent
connection (44) includes a motor used to turn a bit (35) for boring a
directional
hole, while Figure 44 depicts an instance in which the string (40) is rotated
and
the motor turns a boring bit (35) in an opposite rotation below a swivel
connection (48). Embodiments of rock breaking tools (56, 57, 63 and 65 of
Figures 5 to 39) may be added to any configuration of subterranean boring
strings, including those depicted in Figures 43 to 44 in a manner similar to
that
shown in Figure 45.
[000103] Referring now to Figures 45 to 47 embodiments (49A to 49Z) of a
managed
pressure conduit assembly (49) of the present inventor are shown within a one-
half cross sectional elevation view of the passageway through subterranean
strata (52), employing various embodiments (56E, 57D, 57E, 63C, 65K, 65L) of
rock breaking tools (56, 57, 63, 65 of Figures 5 to 39) and various slurry
passageway tools (58 of Figures 45 to 47), which use multi-function tools to
urge first conduit strings (50) and nested additional conduit strings (51)
axially
downward while boring said passageway through subterranean strata forming a
fracturable region (17, 62, 64, 66), extending axially below a lining (51V)
and
cemented (30C) strata bore (17U). The slurry velocity and associated effective
drilling density in the first annular passageway between the tools and the
strata
can be manipulated using slurry passageway tools (58), repeatedly, with multi-
function tools using actuation tools, spear darts and baskets, while also
managing slurry losses, and injecting and compacting LCM created by the rock
breaking tools (56, 57, 63, 65) to inhibit the initiation or propagation of
fractures
within subterranean strata. Additionally, rock breaking tools (56, 57, 61, 63,
65)
and the large diameter of the dual walled drill string can mechanically polish
the
bore through subterranean strata, thereby reducing rotational and axial
friction.
The tools and large diameter of the dual wall string also mechanically apply
and
compact LCM against the filter caked wall of strata into strata pore and
fracture
spaces to further inhibit the initiation or propagation of fractures within
subterranean strata.
[0001041 To urge the passageway through subterranean strata axially downward,
the drill
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bit (35) is rotated with the first string (50) and/or a motor to create a
pilot hole in
the fracturable region (66) within which a bottom hole assembly that includes
a
rock breaking tool (65) with opposing impeller and/or eccentric blades for
breaking rock debris particles generated from the drill bit (35), internally
to said
tools (65), or against the strata walls with said tools (56, 57, 63, 65),
thereby
smearing and polishing the walls of the passageway through subterranean
strata.
[000105] The opposing blades of the rock breaking tools (63C, 65L) and
eccentric blades
of the rock breaking tools (56E, 57D, 57E, 65K) can be provided with rock
cutting, breaking or crushing structures incorporated into the opposing or
eccentric blades for impacting or removing rock protrusions from the wall of
the
passageway through subterranean strata or impacting rock debris internally and
centrifugally. Additionally, when it is not necessary to utilize the rock
breaking
tool (65L) to further break or crush rock debris, or should the rock breaking
tool
(65L) become inoperable, the rock breaking tool (65L) also functions as a
stabilizer along the depicted strings.
[000106] As the additional conduit string (51) of the managed pressure conduit
assembly
(49) is larger than the pilot hole (66), rock breaking tools (63) with first
stage
rock cutters (61A shown in Figures 5 and 6) can be used to enlarge the lower
portion of the passageway through subterranean strata, e.g. fracturable region
(62), and second and/or subsequent stage rock breaking cutters (61B and 61C
shown in Figs. 5 and 6) can further enlarge the passageway, shown as
fracturable region (64), until the additional conduit string (51) with engaged
equipment is able to pass through the enlarged fracturable passageway (17)
through strata. Use of multiple stages of hole enlargement creates smaller
rock
particles that can be broken and/or crushed to form LCM more easily, while
creating a tortuous path through which it is more difficult for larger rock
debris
particles to pass without being broken in the process of passing. Depending on
subterranean strata formation strengths and the desired level of LCM
generation,
rock breaking tools can be provided above the staged passageway enlargement
and rock breaking tools.
[000107] The rock breaking tools (56, 57, 63, 65) of bottom hole assembly
(BHA) and
CA 02752322 2014-12-17
additional conduit string (51) of the managed pressure conduit assembly (49)
bottom hole assembly (BHA) increase the diameter of the drill string, and
create
a narrower outer annulus clearance or tolerance between the string and the
circumference of the subterranean passageway, thereby increasing annular
velocity of slurry moving through the passageway at equivalent flow rates,
increasing annular friction and associated pressure of slurry moving through
the
passageway, and increasing the pressure applied to subterranean strata
formations by the circulating system for fluid pressure coating of the strata
wall.
[000108] Referring now to Figure 45, an elevation view illustrating an
embodiment (49A)
of the managed pressure conduit assembly (49), disposed within a cross section
of the strata passageway (52) is shown, usable for emulating conventional
drilling or casing drilling annular velocities and associated pressures. The
depicted managed pressure conduit assembly (49) can incorporate slurry
passageway tools (58S comprising, e.g., 58 of Figures 45 to 47) with a simple
orifice opening shown to represent said tools and multifunction tools, and
rock
breaking tools (56E, 57D, 57E, 63C, 65K, 65L, comprising, e.g., 56, 57, 63, 65
of Figures 5 to 39) for enlargement of a bore, urging a passageway axially
downward through subterranean strata, and creation of LCM.
[000109] Figure 45 depicts the lower end of the managed pressure conduit
assembly (49)
including an additional conduit string (51) disposed about a first conduit
string
(50), defining an additional annular passageway (54) between the internal
passageway (53) of the first conduit string (50) and the wall of passageway
through subterranean strata (52). Rock breaking tools (56E, 57D, 57E, 63C,
65K, 65L) are also shown, with a slurry passageway tool (58S) usable for
diversion of slurry between the first annular passageway (55) intermediate to
said managed pressure conduit assembly (49) and the subterranean strata, the
additional annular passageway (54), the internal passageway (53), or
combinations thereof
[000110] Referring now to Figure 46, an elevation view of the upper portion of
an
arrangement (49B) of the managed pressure conduit assembly (49) disposed
within a cross-section of the passageway through strata (52) comprising an
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CA 02752322 2014-12-17
upper lined (51V) strata bore or upper fracturable region (17U) and lower
fracturable region (17) with the first conduit (50) passing through the
additional
conduit string (51), is shown. The depicted lower portion of the managed
pressure conduit assembly can be engaged with the upper portion of the
managed pressure conduit assembly depicted in Figure 45, wherein the
additional conduit string (51) is usable to rotate (67) the managed pressure
conduit assembly (49) in a manner similar to conventional casing drilling.
[000111] Figure 46 illustrates: a slurry passageway tool (58T) engaged with
the additional
conduit string (51) and the first conduit string (50), wherein slurry travels
in an
axially downward direction (68) through the internal passageway (54A) of the
additional conduit string (51) until reaching the slurry passageway tool (58T)
after which slurry travels down the additional annular passageway (54) and
within the internal passageway (53) of the first conduit string (50).
[000112] Slurry returns in an axially upward direction (69) within the first
annular
passageway (55), which includes an amalgamation of the first annular
passageway through subterranean strata urged by the managed pressure conduit
assembly (49), the first annular passageway through subterranean strata urged
by the previous drill string and the annular space between the additional
conduit
string (51) and the previously placed protective lining (51V) cemented (30C)
within part of the fracturable previous region (17U), which at least in part,
forms
the wall of the passageway through subterranean strata (52).
[000113] In the depicted arrangement, the managed pressure conduit assembly
(49)
emulates a conventional casing drilling string pressures due to the inside and
outside diameter of the casing or additional conduit string (51), used as a
single
walled drill string at its upper end. While conventional casing drilling
strings
can incidentally generate LCM when its large diameter contacts the
circumference of the passageway during rotation, much of the apparent
generated LCM, seen at the shale shakers during casing drilling, will have
been
generated between said large diameter conduit string and the previously placed
protective casing, where said generated LCM is of no use.
[000114] Referring now to Figure 47, an elevation view of the upper portion of
an
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CA 02752322 2014-12-17
arrangement (49C) of the managed pressure conduit assembly (49) disposed
within a cross section of the passageway through subterranean strata (52),
comprising an exposed lower fracturable region (17) and an upper fracturable
region (17U) that is protected by a lining (51V) which is cemented (30C) into
place and through which the first conduit string (50) and additional conduit
string (51) are positioned below the slurry passageway tools (58A, 58N, 58R),
is
shown. The depicted lower portion of the managed pressure conduit assembly
(49) is engageable with the upper portion of the managed pressure conduit
assembly of Figure 45. The first conduit string (50) is shown as a jointed
drill
pipe string engaged to a slurry passageway tool (58N, 58R) used to rotate the
managed pressure conduit assembly (49) in a selected direction (67), wherein a
connection is made between the inner (50) and outer (51) strings using to the
slurry passageway tool (58T) described in Figure 46. The depicted arrangement
of the managed pressure conduit assembly emulates a liner drilling scenario
externally, but is capable of emulating conventional drilling string
velocities and
associated pressures because fluid flow can occur axially upward between the
inner (50) and outer (51) conduit strings, as shown in the depicted managed
pressure conduit assembly using a dual walled drill string and slurry
passageway
tools (58T, 58N, 58R, 58A).
[000115] The managed pressure conduit assembly (49) of Figure 47 illustrates:
a first
conduit string tool (50) with slurry flowing in an axially downward direction
(68) through the internal passageway of the first conduit sting (50), with a
slurry
passageway tool (58T) engaging the first conduit sting (50) and nested
additional conduit string (51), and with slurry urged in an axially upward
direction (69) through the first annular passageway (55) and additional
annular
passageway (54).
[000116] In this arrangement of the managed pressure conduit assembly (49) the
additional annular passageway flow capacity between the first conduit sting
(50)
and nested additional conduit string (51) may be added to the slurry urged in
the
axially upward direction (69) to selectively emulate conventional annular
velocities and pressures associated with drilling.
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[000117] Additionally, where prior casing drilling normally relies on wire
line retrieval
and replacement of BHA's with drill pipe retrieval used as a contingency
option,
the depicted arrangement enables use of the first conduit sting (50) as the
primary option for retrieval, repair and replacement of internal member parts
of
the managed pressure conduit assembly (49), while enabling the option of
drilling ahead after disengaging the protective casing.
[000118] While wire line retrieval is generally efficient, the size of wire
line units
required to retrieve heavy BHA's is generally prohibitive for many operations
with limited available space, such as offshore operations. Additionally the
length of the a prior art casing drilling lower BHA is often limited due to
weight
restrictions associated with wire line retrieval, thus reducing the utility
and
efficiency of wire line retrieval, such as during situations when long and
heavy
BHA's are required.
[000119] As the conduits of a managed pressure conduit assembly (49) are
stronger than
wire line, the internal member conduit strings may be used to place one or
more
outer nested conduit strings serving as protective lining without first
removing
said drill string.
[000120] Improvements represented by the embodiments of the present invention
described and depicted herein provide significant benefit for drilling and
completing wells where formation fracture pressures are= challenging, or under
circumstances when it is advantageous to urge protective lining strings deeper
than is presently the convention or practice using conventional technology.
[000121] LCM generated using one or more embodiments of the present invention
can be
applied to subterranean strata, fractures and faulted fractures, and/or used
to
supplement surface additions of LCM, increasing the total available LCM
available to inhibit the initiation or propagation of said fractures.
[000122] Subterranean generation of LCM uses the inventory of rock debris
within the
passageway through subterranean strata, reducing the amount and size of debris
which must be removed from a well bore, thereby facilitating improved removal
and transport of unused debris from the subterranean bore. As formations
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become exposed to the pressures and forces of boring and the slurry
circulating
system, LCM generated in the vicinity of the newly exposed subterranean
formations and features can quickly act upon a slurry theft zone in a timely
manner, as detection is not necessary due to said proximity and relatively
short
transport time associated with subterranean generation of LCM.
[000123] Subterranean generation of LCM also avoids potential conflicts with
down hole
tools such as mud motors and logging while drilling tools, by generating
larger
particle sizes after slurry has passed said tools.
[000124] Subterranean generation of larger LCM particles in proximity to the
fracturable
region increases the ability to use the available carrying capacity of the
slurry
for smaller LCM particles, and/or other materials and chemicals added to the
drilling slurry at surface, thus increasing the total amount of LCM sized
particles
and potentially improving the properties of the circulated slurry.
[000125] Embodiments of the present invention also provide means for
application and
compaction of LCM through pressure injection and/or mechanical means.
[000126] Embodiments of the present invention also provide the ability to
manage
pressure in the first annular passageway between apparatus and the passageway
through subterranean strata to inhibit the initiation and propagation of
fractures
and limit slurry losses associated with fractures. The application of these
pressure altering tools and methods is removable and re-selectable without
retrieval of the drilling or completion conduit string used to urge a
passageway
through subterranean strata.
[000127] In summary, embodiments of the present invention both inhibit the
initiation or
propagation of fractures within subterranean strata through timely downhole
generation, supply and application of LCM to target deeper subterranean depths
that is currently the practice of prior art.
[0001281 Embodiments of the present invention thereby provide systems and
methods that
enable any configuration or orientation of single or dual conduit strings
using a
passageway through subterranean strata to generate subterranean LCM to
CA 02752322 2014-12-17
achieve depths greater than is currently practical with existing technology.
[000129] While various embodiments of the present invention have been
described with
emphasis, it should be understood that within the scope of the appended
claims,
the present invention might be practiced other than as specifically described
herein.
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