Note: Descriptions are shown in the official language in which they were submitted.
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MULTIPLE WET ELECTRICAL CONNECTION
MAKE UP IN A WELL
BACKGRO~D OF THE INVENTION
This application is a co"li"~ ;on-in-part of Serial No.
08/119,565 filed September 13, 1993.
This invention relates generally to releasable and reseatable
electrical connections within boreholes, and more particularly, to the
co~ e~;~ion of a wireline to a tool interface.
Wirelines having an inner electrical conductor, a coaxial
insulation layer, and an outer, protective wire covering, are in common usage
in boreholes for connecting ~ul,~ulr~ce electrical equipment for example,
survey or steering tools, to surface electrical eqllipment Such wirelines are
generally routed from the wireline reel of the surface unit through a pulley or
sheave at the upper level of a drilling rig, and may enter the drill string at the
upper end, either through the rotary swivel, or other circ~ ting head
connections, down to the subsurface tool.
While drilling a borehole, it becomes necess~y to add drill
pipe sections to the drill string. In order to achieve this, any wireline withinthe drill string must be withdrawn to facilitate the addition or subtraction of
the drill string elements. Withdrawal of the wireline and the attached tool
may not be economical or easily achievable, especially in the case of very
deep or highly deviated wells. The problems are further m~gnified in
illg the tool and wireline back into a highly deviated borehole, and
effecting a reliable oriented seat at the bottom.
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Fur~ermore, it often becomes necessary to have a combination
of motor or slide drilling, and rotary flrilling, in order to drill a directionally
controlled well path. For these reasons, it is highly desirable to disconnect
the upper section of the wireline so that it may be withdrawn only a short
distance, while leaving the subsurface tool and a length of wireline in the
borehole during the addition of drill pipe sections.
SUl~IARY OF THE INVENTION
The present invenffon provides a releasable and reseatable
electrical connection within the borehole and within the drilling medium, for
effecting an insulative electrical seal against the medium or any ground
source.
Generically, such a cormection may be referred to as an
"electrical wet connection".
The female (top) member is mechanically an electrically
cormected to the wireline, with the wireline conductor being cormected to a
radial contact ring supported by in~ tQrs within its bore. In this
embo-liment clasL~ eric seal gaskets, for example of an O-ring configuration,
are located, such as to extrude drilling fluid as the female member is received
dow.lw~rdly over the male component, to seal against the intrusion of the
drilling medium, and to in~ te bt;lw~;ell potential ground. Also, the contacts
are wiped clean during such reception.
The male (bottom) member includes an llpst~n-ling shaft fitted
with a contact ring ~u~olled by in~ tors and positioned to coact with the
female contact ring once full engagement and seating takes place. The male
member may be part of, or ~tt~hecl to, the ~ub~ulr~ce tool, or to a separate
entity, including support mech~ni~m to hold it at a prescribed location in the
drill string, and connected to the s~lksllrf~ce tool by a dowllw~rdly extçnflin
length of wireline.
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A still further object of the invention is to provide strength,
durability, precision, and positive retention of all con~onelll parts, with radial
holes in the comle-;lion a~aldlus providing an escape path or paths, for
extrusion of drilling fluid during make-up~ the outer housing being made of
high-strength steel. The retained co~ ollent parts can be easily removed,
cleaned, and se~dlely replaced, thus assuring absolute sealing and operation.
An additional object of the invention is to provide a method of
m~king and breaking electrical connection between a series of sections in a
well, each section including male and female members re~e~ rely at its
opposite ends, the members of each section being electrically connected, the
method including the steps
a) sequentially lowering the sections in the well to intercouple
the male and female members of sequential sections, and thereby m~kin~
electrical connection thelebclwt;en, for establishing electrical conmlunication
with a tool in the well,
b) and sequentially raising the sections in the well to decouple
the male and female members of 30 sequential sections, thereby breaking the
electrical connections thel~lween, and for retrieving the sections from the
well.
The hllercoul,ling of the male and female members is typically
effected by lowering of the female member dowllw~dly in the well, over the
male member. Such members also typically have electrical contacts to come
into interengagement, the method including the step of wiping well fluid from
the contacts during hllelcoul)ling.
A further object includes the step of releasing well fluid from
an int.qrn~l trapped fluid zone bc;lw~en the male and female members, as they
interfit. In this regard, the lowermost section is typically landed in the well
prior to sequential lowering of additional of the sections into the well. A
l~n~ling support sleeve is typically provided on the drill string.
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Yet another object includes lowering a latching tool into the
well to latch onto an exposed section, for raising the latter to release from the
next below section. That tool typically includes an overshot, lowered over
successively exposed male members, to latch onto shoulders during raising of
the sections, sllccesxively, from the well.
Yet another object of the present invention is to incorporate a
tilt ring used in conjull;lion with weighted elPm~nt~ above the female
member, and providing additional force to propel the wet connect female
member dowllw~d, and allowing articulating freedom. It also guides and
centers the entrance end of the female wet connect member to initially center
itself relative to and about the male wet connect member, as for example in a
highly deviated hole and to a degree approaching hol;~lllal and beyond.
A still further object of the present invention is the in~roved
construction of the male member body, which typically has two or more arms
extending out radially and configured to have locating slots in each ~ elllily
to accept a key and to be ~u~olled by the keys of the sleeve within the drill
string. The keys have rounded upper ends for m~trlling engagement into the
male wet cormect body, and a tapered knife-like edge configuration for
guidance of any male wet connect member below it, and also having a similar
tapered leading edge, to avoid abutment on extraction from the drill pipe.
The radial arm configuration plesell~ passageways beside the male wet
connect body for the free flow of drilling fluids.
These and other objects and advantages of the invention, as
well as the details of an illu~lldli~/e embo~lim~nt~ will be more fully
understood from the following specification and drawings, in which:
DRAVVING DESCRIPTION
Fig. 1 is a s~ m~tic view of a borehole drilling operation
showing the borehole, a wireline, the ~ul,~ulrace, and the surface eqllipmsnt;
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Fig. 2 is a partial and enlarged cross section taken through the
wet connect members, shown mated together, and ~u~oll~d in a typical
support sleeve within-the drill string;
Fig. 2_ is a section taken on lines 2a-2a of Fig 2;
Fig. 2b is a perspective view of a support sleeve;
Fig. 3 is a cross section taken through the overall female
member of the wet connect;
Fig. 4 is a cross section taken through the male member of the
wet connect;
Fig. 4_ is an elevation taken on lines 4_-4a of Fig. 4;
Fig. 5 is a cross section showing the insulative body of the
female member together with the enc~rs~ te(l electrical wiring;
Fig. 6 is a cross section showing in 6~, 6~, and 6c the insulative
bushings and the contact ring;
Fig. 7 is an exploded view of the component parts of the outer
housing of the female member;
Fig. 8 is a schem~tic illustration; and
Fig. 9 is a sc~t m~tic illustration of multiple electrically
connectible sections in a well.
DETAILED DESCRIPTION
Fig. 1 shows a drilling rig 1 on the surface of the earth 2 for
drilling a borehole 3 into the earth. The drilling is accomplished by a drill bit
4 at the bottom of the drill string made up of individual drill pipe sections 5.As part of the drill and drill collar assembly at the bottom of the string, a
steering or survey tool 6 is provided for me~llring the direction and
inclin~tion of the borehole.
An upper wireline indicated at 7_ is spooled on a reel 8, which
is part of the surface equipment, and is generally controlled and operated by a
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motor drive. The wireline section 7a passes over pulleys or sheaves 9
associated with the rig and extends do~ w~dly into and through drill pipe
sections 5 to a wet connection to connect to a lower wireline section 7b,
which in turn extends to the s~lbsllrf~ce tool. The purpose of the overall
wireline is to carry power and signal data bclween the tool 6 and the surface
eqllipm~nt 10. The reel 8 unwinds, playing out the wireline as the drill string
penetrates further into the earth. The wireline is wound back on the reel 8
when it becomes necessary to extract it and the tool 6, allowing drill string
sections to be added, or removed, from the borehole. Surface equipment 10
is connected to the wireline at the reel 8.
For several purposes, it is de~hdl~lc to have a "wet connection"
in the wireline that may be easily disconnecte-l so that only the upper section
7a of the wireline may be withdrawn, leaving the tool 6 seated or located in
place at the bottom of the drill string, but connected to the male member of a
wet connect in the string near to the surface of the earth, by a length of the
subsurface wireline 7b.
Figs. 2 and 2a are enlarged views of the engaged wet connect
assembly of the female 11 and male 12 members. The assembly is supported
within the ~ul)pol~ sleeve 13 configured to accept the body of the male
member into the keys 13a. Sleeve 13 in turn seats at a shoulder 80 formed
by special section 103 in the string 5. Referring also to Fig. 3, showing the
female upper member 11 in section, the insulative body 14 is assembled in
the outer housing comprising components 15, 16, and 17. A sealing gasket
15a, preferably of an O-ring configuration, is incorporated at the pin and box
connection between 15 and 17, to prevent drilling fluid from entering the
housing. Holes 19 are provided through the housing wall or walls for escape
of the drilling fluid from body bore 84 during subsequent reception of 12 into
84. See arrows 84a. This feature also permits self-flushing, while traversing
within the drill pipe, as well as subsequent cleaning of int~rn~l components.
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An insulative bushing 20 is fitted with oulw~d seals 20a and inward seal
20b, for example of an O-ring configuration, and inserted into the body 14.
See also Fig. 6. The contact assembly 21 carried by 14 below 20 is located
~lim~oncionally over a mating contact ring 21b enc~rsul~ted into the body 14.
A second bushing 22, fitted with oulw~rd seals 22a and inward seal 22b, is
also inserted into and carried by body 14. All items have precision fit and
are positively locked in place with housing skirt 18 incorporating a sealing
gasket 18a between the pin and box connection between 18 and 14, to ~ vel~l
drilling fluid from entering the housing.
Referring now to the male member 12 seen in Fig. 4, a
high-strength steel body 23 fits into and is supported at shoulder 86 by the
keys 13a of a support sleeve 13 also shown in Fig. 2c. The body 23 has two
or more such key engagements providing as many passageways or openings
104 between the body arms 101 to allow circulation of drilling fluids through
the drill string. See Fig. 2a.
The body 23 houses an upwardly directed probe 102, which is
centrally supported and strengthened by a conductive center rod 24.
Electrical connection to the female contact is radially established at a
precision contact ring 25 threaded on the center rod 24. Conductivity is
further L~ lilled down through the body 23 by means of a conductor rod
26, threaded into the center rod 24, and te....i~ ecl a~l,ropliately at the lower
end, for connection to e~..;p..-~nt below it.
The conductive components 24, 25, and 26 are inq~ te(l from
the body 23, and other ground potentials by inqlll~tors 27, 28, 29, 30, and 31,
each of which is made of an in~ tin~ m~t~ri~l, such as PEEK, later
referenced in this text.
The in.qlll~tor sleeve 27 is precision fitted about and screwed
onto the center rod 24 with a gasket 32, preferably of an O-ring
configuration, m~king a leak-tight seal with the contact ring 25. The inqlll~tor
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cap 28 is precision fitted about the upper part of the center rod 24, thread
connected to it, and sealed in a like manner to the in~ tor sleeve 27, with a
gasket 32.
The in~ ted center rod 24 is further in~ul~te(l by means of an
insulative spacer 29 and sealed with a gasket 33, preferably of an O-ring
configuration. In t,his embodiment, a second radial gasket 34 is optionally
employed in similar manner.
The conductor rod 26 may be in~ ted wit,h material, such as
DuPont polytetrafluoroethylene (TFE) Teflon tubing 31. The rod 26 is further
in.~ul~te~l at its lower or exit end 26a wit,h an inml~tQr nut 30, sealed with agasket 36, preferably of an O-ring configuration. In this embo-lim~nt, a
second radial gasket 35 is optionally employed in the same manner.
A similar seal gasket 37 is provided for subsequent sealing to
any ~tt~cllment designed for t,he application.
The probe upper c~llc~ y is equipped wit,h a protective cap or
helmet 38 screwed onto the uppermost inmll~tor cap 28, m~nllf~ctured of a
hard, high-strength material for strength and durabilit,y. The helmet 38 is
conical in shape at its upper end to assist in c~ e~ g during reception into
wet connect female member 11. At that time, drilling fluid in bore 84 of
member 11 is squeeæd out via passages 19.
The body 23 is additionally equipped wit,h a fishing neck or
flange configuration at 39, to facilitate retrieval using either a conventional
"overshot" in usage in the industry, but modified with an enlarged cylindrical
recess to accept the elongated probe section 25, or by a specially fitted
overshot de~i nPrl for the present application.
Fig. 5 shows an axial cross section of the insulative body 14 of
the female member rotated relative to Fig. 3, to illustrate t,he elect,rical
conductor 40 routing from t,he upper elect,rical connection point 41 (to
wireline 7a) to t,he contact ring 42 embedded within its lower confines. See
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Fig. 7, which also illustrates the aforementioned radial e~h~ t ports or holes
19 for the drilling fluid to escape.
The body 14 is made from an in~ ting material having
excellent electrical in~ ting propc.lies, mechanical strength, and limen.cionalstability at the elevated lelllpe,ldlUleS that may be encou~ ed in boreholes.
One suitable material is Victrex PEEK 450GL30, available from the Polymer
Corporation, P.O. Box 422, l~e~-ling, PA. This material consists of glass
fiber-filled polyetheretherketone.
Elements 6a to 6c of Fig. 6 are now referred to. Fig. 6a shows
an axial cross section of the insulative bushing 20, together with its gasket
seals 20a and 20b, as used above the Fig. 6 contact ring 21 for positioning
and sealing purposes. The conducting ring 21, as illustrated in Fig. 6,
consists of a bow spring elenlent 21a wrapped about a conductive cylinder
21f, and bowed outwardly to make positive pres~ulal electrical contact with
the contact ring 42 embedded in the insulative body 14, and a conductive
inner spring element 21b captive within the inner diameter of the cylinder,
and bowed toward the second axis 110. Once engaged, the inner spring
element 21b makes absolute electrical contact with the mating and coacting
contact ring 25 of the male probe member, eYt~n-lin~ about the male member
first axis 111. Axes 110 and 111 align during make-up.
Fig. 6c shows an axial cross section of an insulative bushing
22, like that of Fig. 6a, together with its gasket seals 22a and 22b, for use
below the contact ring 21, for positioning and se~ling Seals 20b and 22b
wipe and seal against the outer cylindrical surface of the probe 102 and
protect 21b and 25. The bushings 20 and 22, made of the in~ tin~ material
PEEK, are identical to that used in the body 14, and incorporate their
respective sealing gaskets of an O-ring configuration to seal against the body
14 and provide a wiping seal for the male probe member, both above and
below the contl~lcting ring engagement.
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Fig. 7 shows a view of the e~tern~l housing component parts,
including rope socket 15, tilt ring 16, housing 17, and skirt 18. The rope
socket 15 in this embodiment has a special rope end configuration, and is
screwed (see thread 40) into the housing 17 cal~tulhlg the tilt ring 16 between
S them, and incol~ol~llhlg a seal gasket lSa. The skirt 18 is screwed (see
thread 41) in place into the housing 17 lower end, after all the internal
collll)ollents are assembled to the housing 17. A seal gasket 18a, like lSa, is
employed to seal off belwt;ell 18 and the lower end of 17. These outer
housing components precisionally confine the electrically in.~ tinp and
con~ cting components, providing a cylindrical high-strength metallic
housing. The e~te.rn~l tilt ring coacts with and allows the female member 11
to self center, relative to the housing in both near vertical and highly
non-vertical, i.e., deviated boreholes.
In operation, the member 12 is carried by the support sIeeve 13
in a vertical section of the drill string, near, i.e., below the drilling rig. The
member 13 is lowered in the bore of the string section to receive the member
12 and any drilling fluid thelebc;lw~;en is squeezed out endwise during make
up. Seating occurs at mating conical surfaces seen at 110 and 111 in Fig. 2.
The contact ring 25 is thereby brought into engagement with the inner spring
elPment 21b on 13, to establish electrical contact, despite a film of fluid
dj~cPnt these elements. The wireline is, accordingly, brought into o~r~liv~
connection, for power and signal data tr~n.~mi.~ion, member 12 being
conne~iled via wireline 7b to 6.
When drill string is to be removed from the hole, the upper
wireline 7a is pulled up, ~let~cl-ing member 13 from member 12, and
removing 13 from the upper string section. An overshot can then be lowered
to connect to member 12, as via neck 39, as referred to above, so that the
wireline can be removed. Then, all the drill string sections can be pulled
from the hole.
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Fig. 8 sçh~m~tically shows an overshot 120 being lowered on a
line 121 to attach neck 39, as referred to above. Overshot body 122 is
connected to 121.
Referring to Fig. 9, it shows a series of like sections 200, 201
S and 202 in a well 203 co.. ~ g a drill string 204. The sections 200--202are made up in a series sequence, and the sections are alike, with a wet
connectible male member 12 at the upper end of the section, and a wet
connectible female member 11 at the lower end of the section. Members 11
and 12 may have the construction as described above. Members 11 and 12 of
each section are electrically connected in the sense also described above, i.e.,they contain electrical elements that are electrically cormected from one end
of the section to the other. The method of sequentially m~king and breaking
electrical cormections between male and female members, as described above,
and at intercoupled locations, includes the steps:
a) sequentially lowering the sections in the well to intercouple
the male and female members of sequential sections, and thereby m~kin~
electrical connection therebetween, for establishing electrical colll,llullication
with a tool deep in the well.
b) and sequentially raising the sections in y the well to
decouple the male and female members of sequential sections, thereby
breaking the electrical connections th~eb~;lw~ell for retrieving the sections
from the well.
Thus, section 200 is first lowered and landed at sleeve 13 in the
string, as by using l~tr.hing tool 120 grasping flange 170 on a male member
12 on section 200, and lowering line 121. Next, tool 120 is employed to
lower the next in sequence section 201 to lower female member 11 of 201
onto male member 12 of 200; and the sequence is repeated for section 202
and further up sections. Electrical cormections are thereby made through the
entire sequence of sections 200--202, etc., to provide electrical conlilluily
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b~wt;en survey tool 6 and the wellhead, as indicated at 220.
In like manner, the sections are sequentially raised, i.e., raise
202, then 201, then 200, to decouple the members 11 and 12, at each wet
connection, when the sections are to be removed. This process enables
S s~1ccescive drill string pipe stands to be connected into the string at the
wellhead, and successive electrical con~ uily sections to be sequentially
lowered, landed, and made up in the well, and within the string, elimin~tin~
need for pulling all the electrical co~ luily sections from the well when drill
string sections are added.
Note that well fluid becoming trapped between members 11
and 12 is released or flushed, as the members 11 and 12 are made up, and
wiped together to establish good electrical connection.
Raising of the sections typically includes lowering of a l~t~hinp
tool into the well to latch onto an exposed upper section, for raising that
section to release from the next below section. Also, l~tçhing of an overshot
to a section involves deep lowering of a l~tç~ing tool onto and over a
member 12 to grasp the flange 170, and for raising or lowering the section.
In the above, it will be noted that each male member body with
its ~ m~nt~ therebelow is individually retrievable axially through the
sleeve and key assembly thereabove.
Further, multiple sets of wet connect components are provided
at selected locations within the drill string, as the bore hole depth increases,to ,,.~ a short distance of wireline withdrawal during drill pipe
connections. To facilitate subsequent extraction of the multiple components,
the male wet connect body has knife-like, upper edges to deflect the body on
engagement with the similar knife-like edges at the bottom of the support
keys, thus allowing it to pass between the keys unobstructed.
As the borehole is drilled deeper, it becomes economically
feasible to add an intermediate section or sections of wireline to reduce the
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length of the upper section of the wireline being traversed into the borehole.
