Note: Descriptions are shown in the official language in which they were submitted.
1~:29 [)~1
sAcKGRo~ND OF THE INVENTION
Well testing and stimulation operations are
commonly conducted on oil and gas wells in order to determine
production potential and to enhance same if possible. In
flow testing a well, a tester valve is lowered into the well
on a string of drill p~pe above a packer. After the packer is
set, the tester valve is opened and closed periodically to
determine formation flow, pressure, and rapidity of pressure
recoveryO
Also generally included in a testing string are a
drill pipe tester valve and a circulation valve above the
tester valve, the former to permit testing the pressure
integrity of the string prior to conducting the test, and the
latter to permit the circulation of formation fluids out of
the string after the test is completed~
It is desirable, particularly when conducting tests
on offshore wells, to employ a testing string which requires
a minimum rotation of reciprocation of the drill pipe to
operate the tools therein, so as to keep the well blowout
preventers closed during the majority of the operation. So-
called annulus pressure responsive downhole tools have been
developed, which tools operate responsive to pressure changes
in annulus between the testing string and the well bore
casing. A number of these annulus pressure responsive tools
are disclosed in the following patents assigned to the
assignee of the present invention. For example, testing
valves are disclosed in U.S. Patent Nos. 3,858,649,
3,856,085, 3,976,136, 3,964,544, 4,144,937, 4,422,506, and
4,429,748. Circulation valves are disclosed in U.S. Patent
Nos. 3,850,250, 3,970,147, 4,113,012, 4,324,293 and
~9~
4,355,685. It is also known to operate a tool to take a
sample of formation fluid with annulus pressure, as disclosed
in U.S. Patent Nos. RE 29,562 and 4,063,593. Moreover, tools
which combine multiple functions have also been developed, as
disclosed in the aforesaid RE 29,562 (testing and sampling)
and U.S. Patent Nos. 4,064,937, 4,270,610 and 4,311,197
(circulating and sampling). While many of the aforesaid tools
provide a biasing source comprising an inert gas under
pressure to oppose annulus pressure, it is also known to
employ a compressible fluid, such as silicone oil, as dis-
closed in U.S. Patent Nos. 4,109,724, 4,109,725, 4,444,268
and 4,448,254. Moreover, the use of a compressed gas in
combination with a fluid, such as oil, is disclosed in U.S.
Patent Nos. 4,422,506 and 4,429,748.
There exist other testing, circulating and sampling
tools and the like which operate in response to annulus
pressure, as disclosed in U.S. Patent Nos. RE 29,638,
3,796,261, 3,823,773, 3,901,314, 3,986,554 and 4,403,659,
assigned to Schlumberger Technology Corporation; U.S. Patent
Nos. 4,105,075 and 4,125,165, assigned to Baker International
Corporation; U.S. Patent No. 4,341,266, assigned to Lynes,
Inc.; and U.S. Patent Nos. 3,891,033 and 4,399,870, assigned
to Hughes Tool Company.
Drill pipe tester valves which operate responsive
to pipe string manipulation are disclosed in U.S. Patent Nos.
4,295,361, 4,319,633, 4,319,634 and 4,421,172, all assigned
to the assignee of the present invention.
While the tools of the prior art are diverse in
design, they suffer from a number of deficiencies in actual
operation. First, while several functions have been combined
1229~4~
into one tool in some instances, the operation thereof
depends upon use of multiple pressures, shearing of pins, or
pressure variation both inside and outside the pipe string.
Inability to maintain precise pressure levels hampers the use
of some of these tools, while the use of shear pins prevents
further operation of other tools after the pins have sheared.
Many prior art tools employing therein a fluid such as oil
utilize fluid metering means such as flow restrictors of a
jet type exemplified by the Lee visco Jet, described in U.S.
Patent No. 3,323,550, in conjunction with check valves. Such
metering means and check valves are susceptible to clogging
and often fail to operate properly if the fluid becomes
contaminated or is of a low quality to begin with, a common
occurrence in many remote areas of the world where these
tools are operated. In addition, the use of fluid metering
means requires an inordinate amount of time to cycle the
prior art tools, thus prolonging time on the jobside and cost
to the well operator. Furthermore, temperature increases or
decreases in the well bore from ambient surface temperatures
change viscosity in the oils employed in these tools, thus
affecting the performance of fluid metering means and
altering tool cycling time. A further disadvantage resides
with those tools utilizing oil, water or other liquids as an
expendable fluid, as they are limited in the number of times
they can be cycled downhole.
Finally, even though some attempts have been made
to combine multiple functions in a single tool, there has
heretofore been no successful combination of more than two
functions in a single tool.
-- 3 --
~2~ 4~
SUMMARY OF THE INVENTION
In contrast to the prior art, the present invention
comprises a downhole tool which is capable of performing in
different modes of operation as a drill pipe tester valve, a
circulation valve and a formation tester valve, as well as
providing its operator with the ability to displace fluids in
the pipe string above the tool with nitrogen or another gas
prior to testing or retesting. This latter function is a
valuable advantage in testing of gas ~ormations or other weak
or low pressure formations which may not flow when subjected
to a large hydrostatic head or which may even be damaged by
the weight of fluid in the string when the formation tester
valve is opened.
The tool of the present invention is operated by a
ball and slot type ratchet mechanism which provides the
desired opening and closing responsive to a series of annulus
pressure increases and decreases of a drill pipe tester/
formation tester valve, a circulation valve and a nitrogen
displacement valve, as well as changing between the modes of
tool operation in which each of these valves function. More-
over, the opening and closing as well as changing between
tool modes is effected without requiring the accurate moni-
toring of pressure levels such as is necessary with tools
that employ multiple pressure levels above a reference level
or both pipe string and annulus pressures. The various tool
modes are mutually exclusive, that is to say, only one mode
is operative at a time to ensure, for example, that the cir-
culation valve and tester valve cannot operate at the same
time. In addition, the tool of the present invention is not
~229~
limited to a given number of cycles in any of its modes,
unlike prior art tools which employ shear pins or expendable
fluids.
Further advantages over prior art tools include
elimination of the need for a bypass below the tool since the
design of the present invention precludes any operation of
the circulating valve due to internal string pressure,
including formation pressure from below the tool or acidizing
or fracturing pressure from above applied to the formation.
Conversely, circulating fluid under pressure is positively
isolated from the formation below, due to the aforesaid
"lock-out" feature which precludes opening of the tester
valve in conjunction with the circulation valve. A further
advantage of the circulation mode is the ability to circulate
in either direction, so as to be able to spot chemicals or
other fluids directly into the testing string bore from the
surface, and then open the tester valve to treat the for-
mation therewith. Also, pumping cold fluid through the tool
will not prevent it from operating.
In addition to the advantages enumerated above, the
present invention includes a novel and unobvious operating
mechanism for fluid displacement in the tool which avoids the
use of the flow restrictors and check valves of the prior
art, such mechanism having utility in a wide variety of
downhole tools, which employ pressure changes as a power
source, and therefore not being so limited to the tool dis-
closed herein. Elimination of a fluid metering system greatly
~2~ 4~
reduces tool cycling time and avoids the effects of viscosity
changes in the metered fluid, as well as providing enhanced
reliability. Another portion of the operating mechanism of
the present invention includes a non-rotating ratchet sleeve
and a rotating ball follower which enhances the reciprocation
of the operating mandrel of the tool as disclosed, but which
is also not so limited to that particular tool, having
utility in other downhole tools as well.
It should be noted that the tool as disclosed is
not limited to the four-mode (drill pipe tester, formation
tester, circulation valve, nitrogen displacement valve)
operation format. It may be employed in conjunction with
another, independently actuated formation tester valve there-
below, and substitute an alternative ratchet slot program to
operate in a three-mode (drill pipe tester, circulation
valve, nitrogen displacement valve) format, or in a two-mode
(circulation valve, nitrogen displacement valve) format.
BRIEF DE5CRIPTION OF THE DRAWINGS
-
The present invention will be more fully understood
by a review of the following detailed description of the
preferred embodiment thereof, in conjunction with the accom-
panying drawings, wherein:
FI5. 1 provides a schematic vertically sectioned
view of a representative offshore platform from which testing
may be conducted and illustrates a formation testing strinq
or tool assembly in a submerged well bore at the lower end of
a string of drill pipe which extends upward to the platform.
FIGS. 2A-2H comprise a vertical half-section of the
t~ol of the present invention in a formation testing mode.
~229~
FIGS. 3A-3~ comprise a vertical half-section of the
tool of the present invention in a drill pipe testing mode~
FIGS. 4A-4H comprise a vertical hal~-section of the
tool of the present invention in a nitrogen displacement
mode.
FIGS. 5A-5H comprise a vertical half section of the
tool of the present invention in a circulating mode.
FIG. 6 comprises a development of the slot design
employed in the preferred embodiment of the tool of the
present invention.
FIGS. 7A and 7B comprise an enlarged section of an
alternative embodiment of the nitrogen displacement valve of
the present invention.
FIGS. 8, 9 and 10 comprise alternative slot designs
which may be employed to alter the mode-changing sequence in
the tool of the present invention.
DETAILED DESrRIPTION OF THE PREFERRED
EMBODIMENT OF THE INVENTION
Referring to FIG. 1, the present invention is shown
schematically incorporated in a testing string deployed in an
offshore oil or gas well. Platform 2 is shown positioned over
a submerged oil or gas well bore 4 located in the sea floor
6, well bore 4 penetrating potential producing formation 8.
Well bore 4 is shown to be lined with steel casing 10, which
is cemented into place. A subsea conduit 12 extends from the
deck 14 of platform 2 into a subsea wellhead 16, which
includes blowout preventer 18 therein. Platform 2 carries a
derrick 20 thereon, as well as a hoisting apparatus 22, and a
pump 24 which communicates with the well bore 4 via control
conduit 26, which extends below blowout preventer 18.
~22~
A testing string 30 is shown disposed in well bore
4, with blowout preventer 18 closed thereabout. Testing
string 30 includes upper drill pipe string 32 which extends
downward from platform 2 to wellhead 16, whereat is located
hydraulically operated "test tree" 34, below which extends
intermediate pipe string 36. Slip joint 38 may be included
in string 36 to compensate for vertical motion imparted to
platform 2 by wave action; slip joint 38 may be similar to
that disclosed in U.S. Patent No. 3,354,950 to Hyde~ Below
slip joint 38, intermediate string 36 extends downwardly to
multi-mode testing tool 50 of the present invention. Below
combination tool 50 is lower pipe string 40, extending to
tubing seal assembly 42, which stabs into packer 44. When
set, packer 44 isolates upper well bore annulus 46 from lower
well bore annulus 48. Packer 44 may be any suitable packer
well known in the art, such as, for example, a Baker Oil Tool
Model D packer, an Otis Engineering Corporation Type W
packer, or Halliburton Services CHAM ~, RTTS or EZ DRILL~ SV
packers. Tubing seal assembly 42 permits testing string 30 to
communicate with lower well bore 48 through perforated tail
pipe 52. In this manner, formation fluids from potential
producing formation 8 may enter lower well bore 48 through
the perforations 54 in casing 10, and be routed into testing
string 30.
After packer 44 is set in well bore 4, a formation
test controllin~ the flow of fluid from potential producing
formation 8 through testing string 30 may be conducted using
variations in pressure effected in upper annulus 46 by pump
24 and control conduit 26, with associated relief valves (not
shown). Prior to the actual test, however, the pressure
12~9~
integrity of testing string 30 may be tested with the valve
ball of the multi-mode tool closed in the tool's drîll pipe
tester mode. Tool 50 may be run into well bore 4 in its drill
pipe tester mode, or it may be run in its circulation valve
mode to automatically fill with fluid, and be cycled to its
drill pipe mode thereafter. Formation pressure, temperature
and recovery time may be measured during the flow test
through the use of instruments incorporated in testing string
30 as known in the art as the ball valve in tool 50 of the
present invention is opened and closed in its formation
tester valve mode. Such instruments are well known in the
art, and include both Bourdon tube-type mechanical gauges,
electronic memory gauges, and sensors run on wireline from
platform 2 inside testing string 30 prior to the test. If the
formation to be tested is suspected to be weak and easily
damageable by the hydrostatic head of fluid in testing string
30, tool 50 may be cycled to its displacement mode and
nitrogen or other inert gas under pressure employed to dis-
place fluids from the string prior to testing or retesting.
It may also be desirable to treat the formation 8
in conjunction with the testing program while testing string
30 is in place. Such a treating program is conducted by
pumping various chemicals and other materials down the
interior of testing string 30 at a pressure sufficient to
force the chemicals and other materials into the formation,
and to possibly fracture the formation. Of course, the
chemicals, materials and pressures employed will vary
depending on the formation characteristics and the desired
changes thought to be effective in enhancing formation
productivity. In this manner it is possible to conduct a
12Z:~ [)41
testing program, treat the formation and a second testing
program to determine treatment effectiveness without removal
of testing string 30. If desired, treating chemicals may be
spotted into testing string 30 from the surface by placing
tool 50 in its circula-tion valve mode, and displacing string
fluids into the annulus prior to opening the valve ball in
tool 50.
At the end of the testing and treating programs,
the circulation valve mode of tool 50 is employed, the circu-
lation valve opened and formation fluids, chemicals and other
injected materials in testing string 30 are circulated from
the interior of testing string 30 into upper annulus 46 using
a clean fluid, packer 44 is released (or tubing seal 42 with-
drawn if packer 44 is to remain in place) and testing string
30 withdrawn from well bore 4.
Referring to FIGS. 2A-2H, tool 50 is shown in
section, commencing at the top of the tool with upper adapter
100 having threads 102 therein at its upper end, whereby tool
50 is secured to drill pipe in the testing string. Uppér
adapter 100 is secured to nitrogen valve housing 104 at
threaded connection 106, housing 104 containing a valve
assembly (not shown), such as is well known in the art, in
lateral bore 108 in the wall thereof, from which extends
downwardly longitudinal nitrogen charging channel 110.
Valve housing 104 is secured by threaded connection
112 at its outer lower end to tubular pressure case 114, and
by threaded connection 11~ at its inner lower end to gas
chamber mandrel 118, case 114 and mandrel 118 defining
pressurized gas chamber 120 and upper oil chamber 122, the
two being separated by floating annular piston 124.
- 10 -
12;~Q~
The upper end of oil channel coupling 126 extends
between case 114 and gas chamber mandrel 118, and is secured
to the lower end of case 114 at threaded connection 128. A
plurality of longitudinal oil channels 130 (one shown)
extend from the upper end of coupling 126 to the lower end
thereof. Radially drilled oil fill ports 132 extend from the
exterior of tool 50, intersecting channels 130 and are closed
with plugs 134. Annular shoulder 136 extends radially inward
from inner wall 138 of coupling 126. The lower end of
coupling 126, including annular overshot 127, is secured at
threaded connection 140 to the upper end of ratchet case 142,
through which oil fill ports 144 extend at annular shoulder
146, being closed by plugs 148. At the lower end of ratchet
case 142 are additional oil fill ports 150 closed by plugs
152 and open pressure ports 154.
Ratchet slot mandrel 156 extends upward within the
lower end of oil channel coupling 126. Annular ratchet
chamber 158 is defined between mandrel 156 and case 142. The
upper exterior 160 of mandrel 156 is of substantially uniform
diameter, while the lower exterior 162 is of greater diameter
so as to provide sufficient wall thickness for ratchet slots
164. There are preferably two such ratchet slots 164 of the
configuration shown in FIG. 6 extending about the exterior of
ratchet slot mandrel 156.
Ball sleeve assembly 166 surrounds ratchet slot
mandrel 156, and comprises upper sleeve 168 including
radially outwardly extending annular shoulder 170 having
annular piston seat 172 thereon. ~elow shoulder 170, ratchet
piston support surface 173 extends to the lower end of upper
sleeve 168, which is overshot by the upper end of lower
-- 11 --
~Z~9~
sleeve 174 having annular piston seat 176 thereon, and to
which is secured at threaded connection 178. Ball sleeve 180
is disposed at the bottom of lower sleeve 174, and is secured
thereto at swivel bearing race 182 by a plurality of bearings
- 184. Two ratchet balls 186 each extend into a ball seat 188
on diametrically opposite sides of ball sleeve 180 and into a
ratchet slot 164 of semicircular cross-section. Due to this
structure when balls 186 follow the path of slots 164, ball
sleeve 180 rotates with respect to lower sleeve 174, the
remainder of ball sleeve assembly 166 does not rotate, and
only longitudinal movement is transmitted to ratchet mandrel
156 by balls 186.
Upper annular ratchet piston 190 and lower annular
ratchet piston 192 ride on piston support surface 173 on
upper sleeve 168, coil spring 194 being disposed there-
between. Upper ratchet piston 190 carries radial sealing
surface 196 on its upper end, while lower ratchet piston 192
carries radial sealing surface 198 on its lower end.
The lower end 200 of ratchet slot mandrel 156 is
secured at threaded connection 202 to extension mandrel 204
having relief ports 208 extending therethrough. Annular lower
oil chamber 210 is defined by ratchet case 142 and extension
mandrel 204. Annular floating piston 212 slidingly seals the
bottom of lower oil chamber 210 and divides it from well
fluid chamber 214 into which pressure ports 154 opens. The
lower end of ratchet case 142 is secured at threaded connec-
tion 218, to extension case 216, which surrounds extension
mandrel 204.
Circulation-displacement housing 220 is threaded at
222 to extension case 216, and possesses a plurality of
circumferentially spaced radially extending circulation ports
224 as well as a plurality of nitrogen displacement ports 226
extending through the wall thereof.
Circulation valve sleeve 228 is threaded to
extension mandrel 204 at 230. Valve apertures 232 extend
through the wall of sleeve 228, and are isolated froln circu-
lation ports 224 by annular seal 234, which is disposed in
seal recess 236 formed by the junction of circulation valve
sleeve 228 with displacement valve sleeve 238, the two being
threaded together at 240. The exterior of displacement valve
sleeve 238 carries thereon downwardly facing radially
extending annular shoulder 242 thereon, against which bears
displacement spring 244. The lower exterior of displacement
valve sleeve 238 is defined by displacement piston surface
246 upon which sliding annular displacement piston 248 rides.
Annular valve surface 250 of piston 248, and seats on
elastomeric valve seat 254. Nitrogen displacement apertures
256 extend through the wall of displacement valve sleeve 238.
Valve seat 254 is pinched between sleeve 238 and shoulder 257
of sleeve 238 and flange 258 of operating mandrel 260, which
is secured to sleeve 238 at threaded connection 262.
Seal carrier 264 surrounds mandrel 260 and the
junction of mandrel 260 with sleeve 238 and is secured to
mandrel 260 at threaded connection 265. Square cross-section
annular seal 266 is carried on the exterior of mandrel 260
adjacent flange 258, and is secured in place by the upper end
of seal carrier 264.
~.229 [)~1
selow seal carrier 264, mandrel 260 extends down-
wardly to exterior annular recess 267, which separates
annular shoulder 268 from the main body of mandrel 260.
Collet sleeve 270, having collet fingers 272
extending upward therefrom, engages operating mandrel 260
through the accommodation of radially inwardly extending
protuberances 274 by annular recess 267. As is readily noted
in FIG. 2G, protuberances 274 and the upper portions of
fingers 272 are confined between the exterior of mandrel 260
and the interior of circulation-displacement housing 220.
At the lower end of collet sleeve 270, coupling 276
comprising flanges 278 and 280, with exterior annular recess
282 therebetween, grips coupling 284, comprising inwardly
extending flanges 286 and 288 with interior recess 2g0 there-
between, on each of two ball operating arms 292. Couplings
276 and 284 are maintained in engagement by their location in
annular recess 296 between ball case 294, which is threaded
at 295 to circulation-displacement housing 220, and ball
housing 298. Ball housing 298 is of substantially tubular
configuration, having an upper smaller diameter portion 30C
and a lower, larger diameter portion 302 which has two
windows 304 cut through the wall thereof to accommodate the
inward protrusion of lugs 306 from each of the two ball
operating arms 292. Windows 304 extend from shoulder 311
downward to shoulder 314 adjacent threaded connection 316
: with ball support 340. On the exterior of the ball housing
: 298, two longitudinal channels ~location shown by arrow 308)
of arcuate cross-section and circumferentially aligned with
windows 304, extend from shoulder 310 downward to shoulder
311. Ball operating arms 292, which are of substantially the
- 14 -
1229 [)4~
same arcuate cross-section as channels 308 and lower portion
302 of ball housing 298, lie in channels 308 and across
windows 304, and are maintained in place by the interior wall
318 of ball case 294 and the exterior of ball support 340.
The interior of ball housing 298 possesses upper
annular seat recess 320, within which annula.r ball seat 322
is disposed, being biased downwardly against ball 330 by ring
spring 324. Surface 326 of upper seat 322 comprises a metal
sealing surface, which provides a sliding seal with the
exterior 332 of valve ball 330.
Valve ball 330 includes a diametrical bore 334
therethrough, of substantially the same diameter as bore 328
of ball housing 298. Two lug recesses 336 extend from the
exterior 332 of valve ball 330 to bore 334.
The upper end 342 of ball support 340 extends into
ball housing 298, and carries lower ball seat recess 344 in
which annular lower ball seat 346 is disposed. Lower ball
seat 346 possesses arcuate metal sealing surface 348 which
slidingly seals against the exterior 332 of valve ball 330.
When ball housing 298 is made up with ball support 340, upper
and lower ball seats 322 and 346 are biased into sealing
engagement with valve ball 330 by spring 324.
Exterior annular shoulder 350 on ball support 340
is contacted by the upper ends 352 of splines 354 on the
exterior of ball case 294, whereby the assembly of ball
housing 294, ball operating arms 292, valve ball 330, ball
seats 322 and 346 and spring 324 are maintained in position
inside of ball case 294. Splines 354 engage splines 356 on
~L22~Q41
the exterior of ball support 340, and thus rotation of the
ball support 340 and ball housing 298 within ball case 298 is
prevented.
Lower adapter 360 protrudes at its upper end 362
between ball case 298 and ball support 340, sealing
therebetween, when made up with ball support 340 at threaded
connection 364. The lower end of lower adapter 360 carries on
its exterior threads 366 for making up with portions of a
test string below tool 50.
When valve ball 330 is in its open position, as
shown in FIG. 2G, a "full open" bore 370 extends throughout
tool 50, providing an unimpeded path for formation fluids
and/or for perforating guns, wireline instrumentation, etc.
OPERATION OF ~HE PREFERRED EMBODIMENT
OF THE PRESENT INVENTION
Referring to FIGS. 1 through 6, operation of the
combination tool 50 of the present invention is described
hereafter.
As tool 50 is run into the well in testing string
30, it is normally in its drill pipe tester mode shown in
FIGS. 3A-H, with ball 330 in its closed position, with ball
bore 334 perpendicular to tool bore 370. In this position,
circulation ports 224 are misaligned with circulation aper-
tures 232, seal 234 preventing communication therebetween. In
a similar fashion, nitrogen displacement ports 226 are offset
from displacement apertures 256 and isolated therefrom by
seal 266. With respect to FIG 6, balls 186 will be in
positions "a" in slots 164 as tool 50 is run into the well
bore.
- 16 -
~229~
As tool 50 travels down to the level of the for-
mation 8 to be tested, at which position packer 44 is set,
floating piston 212 moves upward under hydrostatic pressure,
pushing ball sleeve assembly 166 upward, and causing balls
186 to move to positions "b", which does not change tool
modes or open any valves. A pressure integrity check of the
testing string 30 above tool 50 may then be conducted before
flow testing the formation.
In order to open valve ball 330 to conduct a flow
test of a formation, pressure is increased in annulus 46 by
pump 24, via control conduit 26. This increase in pressure is
transmitted through pressure ports 154 into well fluid
chamber 214, where it acts upon floating piston 212. Piston
212 in turn acts upon a fluid, such as silicone oil, in lower
oil chamber 210, which communicates with ratchet chamber 158.
In ratchet chamber 158, the pressurized oil pushes against
upper ratchet piston 190, the oil being prevented from by-
passing piston 190 by the metal to metal seal of sealing
surface 196 on piston seat 172. Piston 190 therefore pushes
against shoulder 170 on upper sleeve 168, which in turn pulls
lower sleeve 174, ball sleeve 180 and balls 186 upward in
slots 164. In this manner, balls 186 are moved to positions
c, which has no effect on tool operation as balls 186 do not
shoulder on the ends of slots 164 in this position. The
aforesaid feature is advantageous in that it permits
pressuring of the well bore annulus 46 to test the seal of
packer 44 across the well bore 4 without opening valve ball
330. By way of elaboration, when piston 190 reaches overshot
127, it is restrained from further upward movement, but fluid
continues to act on shoulder 170 of upper sleeve 168,
- 17 -
~2Z~)4~L
spreading piston seat 172 from seating surface 196, breaking
the seal and dumping fluid past upper sleeve 168 into oil
channels 130 and upper oil chamber 122, which equalizes the
pressures on both sides of piston 190 and stops the movement
of ball sleeve assembly 166 and of balls 186 in slots 164. As
the length of the slot is greater than the travel of the ball
sleeve assembly, balls 186 stop short of the slot end. As
annulus pressure is bled off, the pressurized nitrogen in
chamber 120 pushes against floating piston 124, which
pressure is transmitted through upper oil chamber 122,
channels 130 and ratchet chamber 158 against lower ratchet
piston 176. As ratchet piston 176 is biased against piston
seat 176, a metal to metal seal is effected between radial
sealing surface 198 and seat 176. Ball sleeve assembly 166 is
therefore biased downwardly, ratchet balls 186 following the
paths of slots 164 to position d1, where they shoulder on the
ends of the slots. Tool 50 is now in its formation tester
valve mode as shown in FIGS. 2A-2H, but with valve ball 330
closed. When lower ratchet piston 192 reaches annular
shoulder 146 in its downward travel, fluid continues to act
on ball sleeve assembly 166, spreading sealing surface 198
from seat 176. Fluid is thus dumped below ball sleeve
assembly 166 and is thereby equalized, stopping the travel of
ball sleeve assembly 166, balls 186 and ratchet mandrel 156.
When the well bore annulus is again pressured, ball
sleeve assembly 166 moves upward and balls 186 shoulder in
slots 164 at position el moving ratchet mandrel 156 upward,
which pulls extension mandrel 204, circulation valve sleeve
228, displacement valve sleeve 238 and operating mandrel 260
upward. Operating mandrel 260 pulls collet sleeve 270 upward,
- 18 -
122~
which pulls arms 292 and rotates valve ball 330, aligning
ball bore 334 with tool bore 370, permitting the formation to
flow into the testing string 30 above tool 50. Tool 50 is now
in the tester valve mode shown in FIGS. 2A-2H with valve ball
330 open. When annulus pressure is released, balls 186
shoulder at position d2, and close valve ball 330, but tool
50 is still in the tester mode of FIGS. 2A-2H. The process of
pressuring and releasing pressure may be continued to open
and close ball 330 to flow test the formation until balls 186
reach positions d6.
A subsequent increase in annulus pressure will
shoulder balls 186 momentarily on inclined edges 164a before
moving further along slots 164 past positions f but valve
ball 330 will not open. When pressure is released again,
balls 186 move downward and shoulder in positions f, moving
ratchet mandrel 156 downward and tool 50 out of its formation
tester mode and back into the nitrogen displacement mode of
FIGS. 4A-~. As can readily be seen in Fig. 4H, protuberances
274 on collet sleeve fingers 272 are disengaged from oper-
ating mandrel 260 in this mode, preventing rotation and re-
opening of ball 330.
A subsequent increase and decrease of annulus
pressure causes balls 186 to climb further in slots 164 past
positions g, and then to push ratchet mandrel 156 downward,
moving tool 50 to its circulation valve mode shown in FIGS.
5A-H. Fluid may be circulated into the testing string 30 from
annulus 46 throu~h circulation ports 224, which are aligned
with circulation apertures 232, ball valve 330 in its closed
position and nitrogen displacement ports 224 offset from
apertures 256. Fluid may also be circulated into annulus 46
-- lg --
lZ~ 41
from the testing string 30, as when it is desired to spot
formation treatment chemicals into the string prio~ to an
acidizing or fracturing operation. As may be easily observed
in FIG. 5G, operating mandrel 156 has continued to travel
downward within collet sleeve 270 but out of engagement with
protuberances 274.
Subsequent pressure increases and decreases in the
annulus will move balls 186 sequentially to positions hl, i1'
h2, i2, and h3 without changing tool 50 from its circulation
mode, as balls 186 do not shoulder in slots 164. This
provides a margin of safety against changing of tool modes
due to inadvertent pressure cycling in the annulus during
circulation.
As annulus pressure is decreased after balls 186
reach positions h3, they will move downward past positions j,
whereupon a subsequent annulus pressure increase will
shoulder balls 186 in positions j, moving ratchet mandrel 156
upward and tool 50 back into its nitrogen displacement mode
of FIGS. 4A-H. If treatment chemicals have not been spotted
in the string, and if it is desired to displace fluid out of
the testing string 30 prior to a further test, as where the
formation has not flowed initially due to hydrostatic head of
fluid in the string, nitrogen may be introduced into the
testing string 30 under pressure. In this mode, valve ball
330 is closed and circulation ports 224 offset from apertures
232, but nitrogen displacement ports 226 are aligned with
apertures 256. The pressurized nitrogen will act upon dis-
placement piston 248, moving it away from seat 254, and
permit fluid in the string to exit into the well bore
annulus. When pressure is reduced in the string, annulus
- 20 -
~229~
pressure outside tool 50 will act upon the upper end of dis-
placement piston 248 through circulation ports 224, and
firmly press valve surface 250 against seat 254, preventing
re-entry of fluid into the string.
As in the circulation mode, several subsequent
increases and decreases in annulus pressure will move balls
186 in slots 164, but will not change the mode of tool 50. As
pressure is decreased and increased sequentially when balls
are in positions j, they move to positions kl, 11, k2 and 12.
when pressure is again decreased with balls 186 in position
12, they will move downward in slots 164 past position m,
where a subsequent increase will shoulder balls 186 out on
slots 164 in positions m, changing tool mode to the drill
pipe tester mode of FIGS. 3A-H, offsetting nitrogen dis-
placement ports and apertures, lea~ing circulation ports and
apertures offset, and leaving valve ball 330 closed. A
further decrease in pressure will return balls 186 to posi-
tions a, and the operator may begin another cycle of tool 50,
' such as to treat the formation and retest it after the treat-
ment, or test it with the string unloaded of fluid.
By way of further explanation of the mode changing
and operating sequence of tool 50, the reader should note
that the tool only changes mode when balls 186 shoulder at
specific foreshortened positions on slot 164 during cycling
of the tool. For example, tool 50 changes mode at positions
dl, d6, f, g, ] and m. Four mode changes are effected by
annulus pressure decrease, and two by an increase. The
pressure increases which shoulder balls 186 in positions el
through eS do not produce a mode change because balls 186
; 30 travel within a restricted longitudinal range limited by the
~:;
- 21 -
41
dumping of the operating fluid in the tool by pis-tons 190 and
192, and the configuration of the slots 164 from positions el
through e5 does not permit balls 186 to climb in slots 164 to
change tool modes.
OPERATION OF A SECOND PREFERRED EMBODIMENT OF
THE PRESENT INVENTION
As has previously been noted, tool 50 of the
present invention may be changed to operate in a three-mode
sequence as a drill pipe tester, circulation valve and
nitrogen displacement valve in conjunction with a separate
tester valve therebelow in the string by merely removing
ratchet mandrel 156 and inserting another mandrel 156' having
a different slot program 164' therein. Such a mandrel slot
program 164' is shown in FIG. 8. In all respects other than
substitution of mandrel 156' for mandrel 156, tool 50 remains
structurally the same even though its modes of operation have
been al~ered.
With slot 164', tool 50 is run into the well bore
in its drill pipe tester mode with balls 186 in positions a
as shown in FIG. 8 and tool 50 in the mode shown in FIGS.
3A-H. As tool 50 travels down the well bore, hydrostatic
annulus pressure will move balls 186 to position b. As valve
ball 330 remains closed, an integrity test of the drill pipe
may be conducted. The first increase in annulus pressure
subsequent to the drill pipe test will move balls 186 to
positions c, which will not change tool mode, and a
subsequent decrease and increase will shoulder balls on slot
164' at position d, which will rotate valve ball 330 to an
open position, aligning bore 334 with tool bore 370 as shown
in FIGS. 2~-2H. This same pressure increase will have opened
- 22 -
9~41
the ball of the tester valve therebelow, which may be a valve
such as are disclosed in U.S. Patent Nos. 3,964,544,
3,976,136, 4,422,506, 4,429,748, as well as others ~nown in
the art. The formation then flows through the tester valve
and tool 50 during the test. When annulus pressure is de-
creased to close the tester valve, the decrease will move
balls 186 to positions e1, which will not close valve ball
330 because balls 186 do not shoulder on slots 16~'.
Subsequent pressure increases and decreases to flow test the
0 well via the tester valve will move balls 186 sequentially to
1~ e2~ f2~ e3~ f3 and e4, during which valve ball
330 of tool S0 will remain open. During the next subsequent
annulus pressure increase when in position e4, balls 186 will
climb in slot 164' past positions g, valve ball 330 remaining
open. When annulus pressure is relieved, however, balls 186
will shoulder in positions g and move ratchet mandrel 156'
downward, closing-valve ball 330 and returning tool 50 to its
drill pipe tester mode shown in FIGS. 3A-H.
Another increase and decrease in annulus pressure
will move balls 186 to shoulder in positions h, changing tool
to the nitrogen displacement mode of FIGS. 4A-H. A second
increase/decrease pxessure cycle will move balls 186 to
positions i and tool S0 to the circulation mode of FIGS.
SA-SH.
Subsequent increases and decreases in annulus
pressure will ratchet balls 186 through positions il- i2, j2,
i3, j3, and do~n past kl without changing tool mode, after
which an increase will shoulder balls 186 in positions kl,
changing tool 50 to the nitrogen displacement mode of FIGS.
4A-4H.
~22~
Further annulus pressure cycling in decrease/
increase sequence will move balls 186 to positions 11, k2,
12, k3 and down past positions m without changing tool mode.
A subsequent pressure increase will shoulder balls
186 in positions m and change tool 50 to its drill pipe
tester mode of FIGS. 3A-H. Further pressure cycling of the
annulus will begin another tool cycle.
As noted with respect to slot 164, tool 50 only
changes mode when balls 186 shoulder in foreshortened paths
in the slot. In slot 164' for example, tool mode changes only
in ball positions d, g, h, il, kl, and m. In all other
instances, balls 186 merely travel slots 164' with no effect
on tool operation.
ALTERNATIVE EMBODIMENTS OF THE
_
PRESENT INVENTION
It is also possible to re-program tool 50 of the
present invention to effect modes of operation other than
those disclosed with respect to the first and second
preferred embodiments.
For example, referring to FIG. 9, the program of
slot 164" is shown. Using mandrel 156" with slot 164", tool
50 is run into the well bore in its drill pipe tester mode of
FIGS. 3A-3H, with balls 186 in positions a in slots 164.
Going downhole, balls 186 will be forced upward to positions
b by hydrostatic pressure in the annulus. A drill pipe
integrity test may be conducted when tool 50 reaches the test
level in the well bore.
After the packer is set, the formation may be flow
tested by raising annulus pressure, lowering it and raising
it again, which moves balls up through portions c, down past
- 24 -
1229~
portions d1, and up to dl whereat balls 186 shoulder and open
valve ball 330, tool 50 being in the tester valve mode of
FIGS. 2A-H. A subsequent decrease in annulus pressure will
move balls 186 to position el, which will retain valve bal~
330 in an open position. Another increase/decrease cycle
will close valve ball 330 due to shouldering of balls 186 in
positions fl and downward movement of ratchet mandrel 156.
Another increase/decrease cycle will result in ball movement
to positions gl, and down past d2, with valve ball 330
remaining closed~ The next increase/decrease opens valve ball
330 when balls 186 shoulder in positions d2, and leave valve
ball 330 open when balls 186 travel to positions e2. The
following increase/decrease shoulders balls 186 in positions
f2 as annulus pressure is relieved, closing valve ball 330. A
further increase/decrease moves balls 186 to position g2 and
back down below d3, after which the next subsequent
increase/decrease shoulders balls 186 in positions d3,
opening valve ball 330 and leaving it open as balls 186 land
at position e3.
To continue the tool cycle, an annulus pressure
increase/decrease moves balls 186 to f3, closing valve ball
330. Balls 186 climb slots 164"' with the next
increase/decrease to position h, whereat tool 50 is shifted
to its nitrogen displacement mode of FIGS. 4A-H, and then to
its circulation mode of FIGS. 5A-H when annulus pressure is
again cycled and balls 186 shoulder in positions il.
The next three increase/decrease cycles in annulus
pressure will move balls 186 through positions il, i2, j2,
i3, j3 and back down past position kl. During this travel,
balls 186 do not shoulder, and the tool 50 does not change
- 25 -
1229~4~
mode. However, the next subsequent increase in pressure will
shoulder balls 186 in position kl, change tool mode to the
nitrogen displacement mode of FIGS. ~A-H.
The next two decrease/increase pressure cycles move
balls 186 through positions 11, k2, 12 and k3 without change
in tool mode. During the following decrease/increase cycle,
however the tool is moved back to its drill pipe test mode of
FIGS. 3A-H when balls 181 move downward below positions on
the decrease and then shoulder as pressure is increased. When
annulus pressure is next decreased, balls 186 move back to
positions a for commencement of a new tool cycle.
As was noted with respect to the previous operating
mandrels 156 and 156' mandrel 156" does not move longitu-
dinally to operate valve ball 330 and to change tool modes
unless balls 186 shoulder in foreshortened legs of slots
164". In slots 164", only positions dl, f3, h, il, kl, and m
produce a change of mode. Positions dl, fl, d2, f2, d3 and
f3, however, all serve to open and close, respectively valve
ball 330.
With the slot program employed in slot 164", the
test operator must positively pressure the annulus and then
relieve pressure for valve ball 330 to move from a closed to
an open position and vice-versa, which feature prevents a
shutoff in the middle of a flow test if annulus pressure is
reduced inadvertently. Furthermore, valve ball 330 may be
left open after the formation test and circulation, to let
testing string 30 drain of fluid as it is removed from well
bore 4.
- 26 -
~22~
Another embodiment of the present invention may be
effected utilizing yet another slot program, illustrated in
FIG. 10 as slot 164"' on mandrel 156"'. With slots 164"',
tool 50 is restricted to a two-mode operation, circulation
valve, which would be preferred in some areas of the world
which do not conduct drill pipe tests prior to flow testing
the well, and which use a separate tester valve below tool
50.
With slots 164"', ratchet balls 186 commence in
positions a, and move to be as tool 50 travels down the well
bore. Valve ball 330 is open. A first annulus pressure
increase after packer 44 is set will result in ball movement
to positions cl, and subsequent decrease/increase cycling
will move balls 186 through positions dl, c2, d2 and C3 to
d3. The next three increase/decrease pressure cycles will
result in balls 186 climbing slots 164"' to positions e,
which closes valve ball 330; positions f, which places tool
50 in its displacement valve made; and position 91' which
places tool 50 in its circulation valve mode. The next three
increase/decrease pressure cycles will result in free ball
movement through positions hl, g2, h2, g3 and h3 past il,
without moving tool 50 from its circulation valve mode.
However, a subsequent increase will change tool mode to dis-
placement valve, as balls 186 shoulder in positions il. This
mode is maintained through the next two decrease/increase
cycles with free ball travel. The next decrease/increase
cycle then moves balls 186 to shoulder in positions k, which
o~fsets both displacement ports 226 from displacement aper-
tures 256 and circulation ports 224 from circulation aper-
tures 232 while leaving valve ball 330 closed. The next
- 27 -
1229 E)~1
subsequent decrease/increase cycle will again open valve ball
330 with balls 186 in positions 1, and an annulus pressure
decrease will place balls back in positions a for another
tool cycle. In slots 164"', balls 186 shoulder in positions
' f' gl' ilr k and 1.
ALTERNATIVE EMBODIMENT OF THE DISPLACEMENT VALVE
OF THE PRESENT INVENTION
FIGS. 7A and 7B illustrate an alternative construc-
tion for a nitrogen displacement valve assembly which may be
employed in tool 50. Valve assembly 400 includes an outer
circulation-displacement housing 220' with slightly longer
spacing between circulation ports 224 and displacement aper-
tures 234 than in standard housing 220. At its upper end,
housing 220' is secured at threaded connection 222 to
extension case 216, while at its lower end (not shown) it is
secured to ball case 294. Within tool 50, extension mandrel
204 is secured at threaded connection 230 to circulation
valve sleeve 228, through which circulation apertures 232
extend. Sleeve 228 is threaded to displacement valve sleeve
238', seal 234 being maintained in an annular recess 236
therebetween to isolate circulation apertures 232 from circu-
lation ports 224.
On the exterior of displacement valve sleeve 238'
lie annular marker grooves 420 (three grooves), 422 (two
grooves) and 424 ( one groove), the purpose of which will be
explained hereafter. Below the marker grooves displacement
apertures 256 extend through the wall of sleeve 238' adjacent
obliquely inclined annular wall 416, which is a part of dis-
placement assembly 400.
- 28 -
12~4~
Flapper mandrel 406 slides on the exterior of
sleeve 238' below wall 416, and is restricted in its longitu-
dinal travel by the abutment o~ elastomeric seal 414 against
wall 416 at its upper extent, and by the abutment of shoulder
408 against stop 404 extending upward from shoulder 402 on
operating mandrel 260'. Stops 404 prevent pressure locking of
shoulder 408 to shoulder 402. Seal 266 is maintained in a
recess between annular shoulder 258' on mandrel 260' and seal
carrier 264, which surrounds threaded connection 262 between
sleeve 238' and operating mandrel 260', and is itsel~ secured
to operating mandrel 260' at threaded connection 265.
Flapper mandrel 406 carries thereon a plurality of
frustoconical valve flappers 412 thereon, which are bonded to
mandrel 406 adjacent annular shoulders 410.
Displacement assembly 400 is placed in its opera-
tive mode in the same fashion as the displacement mode of
tool 50 in FIGS. 2-S, that is by longitudinally moving the
internal assembly connected to ratchet mandrel 155 through
the interaction of balls 186 in slots 164. However, unlike
displacement piston 248 which is spring-biased toward a
closed position against seat 254 ~FIGS. 2E-F, 3E-F) and is
moved therefrom by nitrogen flowing under pressure through
apertures 256 (FIGS. 4E-F), mandrel 406 operates when placed
adjacent displacement ports 226 (FIGS. 7A-B) through downward
movement against stops 404 follo~ed by collapse of flappers
412 against mandrel 406 to permit exit through ports 226 of
the fluid in the string and the pressuri2ed nitrogen
impelling it into the well bore annulus.
- 29 -
i2~
If pressure is removed from the bore 370 of tool
50, the hydrostatic head (and pressure) in the annulus will
expand flappers 412 against circulation-displacement housing
220' and move mandrel 406 upward against wall 416, whereon
elastomeric seal 414 will seat, preventing re-entry of
annulus fluids into bore 370.
An added feature of assembly 400 is the ease of
identification of tool mode through the use of marker grooves
420, 422 and 424. For example, when tool 50 is in its circu-
lation mode, circulation ports 224 will be aligned with cir-
culation apertures 232 and no grooves will be visible. When
tool 50 is in its displacement mode (FIGS. 7~-B), grooves 420
will be visibleO When valve ball 330 is closed, grooves 422
will be visible, and when valve ball 330 is open, groove 420
will be visible. With knowledge of which ratchet mandrel is
employed in tool 50 and the initial portion desired, the tool
will then be easily able to ensure placement of tool 50 in
its proper mode for running into the well bore.
It is thus apparent that a novel and unobvious
multi-mode testing tool has been developed, which further
includes a novel and unobvious operating mechanism and valves
therein. It will be readily apparent to one of ordinary skill
in the art that numerous additions, deletions and modifi-
cations may be made to the invention as disclosed in its
preferred and alternative embodiments as disclosed herein.
For example, tool 50 might employ an all-oil operating
biasing mechanism such as is disclosed in U.S. Patent Nos.
4,109,724, 4,109,725, 4,444,268 and 4,448,254; the nitrogen
displacement valve might be placed above the circulation
valve in the tool; alternative pressure-responsive check
- 30 -
1229~
valve designs might be employed as displacement valves;
Belleville or other springs might be substituted for the coil
springs shown in tool 50; the operating mechanism of the
tool, including nitrogen and/or oil chambers, the ratchet
mandrel and the ball sleeve assembly could be placed at the
bottom of the tool or between the ends thereof; the ratchet
balls could be seated in recesses on a mandrel and a rotating
ratchet sleeve with slots cut on the interior thereof might
be employed therearound and joined by swivel means to a
sleeve assembly carrying annular pistons 190 and 192 thereon;
a ratchet sleeve might be rotatably mounted about a separate
mandrel and ratchet balls mounted in a non-rotating sleeve
assembly thereabout; a sleeve-type valve such as is disclosed
in U.S. Patent RE 29,562 might be utilized to close bore 370
through tool 50 in lieu of a ball valve; an annular sample
chamber might be added to tool 50 such as is also disclosed
in the afore-said U.S. Patent RE 29,562; a second valve ball
might be included longitudinally spaced from valve ball 330
and secured to operating mandrel 260 to form a ball-type
sampler having a mechanism similar to those disclosed in U.S.
Patent Nos. 4,064,937, 4,270,610 and 4,311,197; the valve
ball 330 could be placed at the top of the tool and employed
for drill pipe test purposes only with another tester valve
run below the tool, as has been heretofore suggested; an
annular piston having a longitudinal channel therein with a
; resiliently biased check valve closure member and valve seats
at each end thereof may be substituted for the piston sleeve
and pistons of the preferred embodiment, using for stop means
a pin or rod adapted to push the check valve closure member
back from its seat at each limit of piston travel to dump
12~
fluid therepast. These and other changes may be effected
without departing from the spirit and scope of the claimed
invention.
This application is a divisional of Canadian Patent
Application No. 474,772, filed February 20, 1985.
- 32 -
