Hydraulic release apparatus and method for retrieving a stuck downhole tool and moving a downhole tool longitudinally

A hydraulic release mechanism for retrieving a stock downhole tool from a well casing having an elongated, cylindrical jack body, a piston carried in a bore in the jack body and a latching portion carried co-axially by the jack body for connecting with the stock tool. The piston is movable within the jack body under the influence of fluid pressure from a first position to a second position. The movement of the piston to a position intermediate its first and second positions causes an anchor slip member to ramp over a wedge member and expand radially outward against the well casing to restrain further longitudinal movement of the piston in the casing. A shearable element prevents relative motion between the anchor slip member and the jack body until the anchor slip member is moved radially outward against the well casing. The shearable element shears and releases the jack body for longitudinal motion in the casing relative to the piston when the anchor slip member is expanded radially outward against the casing, locking the piston in place. The latching portion is operatively engageable with the tool in a manner permitting the stuck tool to be lifted loose when the jack body is moved longitudinally relative to the locked piston under the influence of hydraulic pressure until the locked piston assumes its second position in the jack body.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to cable or reeled tubing-deployed pumping systems 
for use in oil and gas wells, and more particularly, to an emergency 
hydraulic release for the locking module discharge head in a 
cable-deployed or reeled tubing-deployed pumping system. A further 
embodiment of the invention relates to cable or reeled tubing hydraulic 
release apparatus for loosening a stuck downhole tool from a well casing 
for subsequent retrieval, or moving a downhole tool longitudinally to 
perform an operation in the well. 
2. Description of the Background 
Artificial lift systems for use in oil and gas wells are well known. One 
type of artificial lift system is a cable deployed pumping system as 
previously disclosed, for example, in U.S. Pat. No. 4,913,239. The 
cable-deployed pumping system allows electric submersible pumps to be 
installed and retrieved by means of a crush-resistant electrical cable 
that can be field-spliced and is designed to withstand the gripping forces 
of an injector and the rigors of downhole service. This is a 
cost-effective alternative to conventional tubing deployment and offers 
faster installation and retrieval with smaller equipment and few 
personnel. 
In a standard installation for a cable-deployed pumping system, whether 
using a conventional pump or inverted pump, an electric submersible pump, 
motor and locking module discharge head are first connected to the 
electrical cable using a cable anchor assembly and an electrical 
penetrator assembly. The pumping system is then injected into the well 
through production tubing by means such as a modified reeled tubing 
injector. As the cable is lowered into the well, a collet latch on the 
locking module engages a locking module landing nipple disposed in the 
tubing string. After a subsurface safety valve below the landing nipple is 
opened by control fluid pressure exerted through a control line, the 
electric submersible pump can be activated to begin pumping well fluids to 
the surface. When it is desired to retrieve the pumping system from the 
well, the locking module is disengaged from the landing nipple by pulling 
upward on the electric cable. 
In using the previously known cable-deployed pumping systems, problems have 
sometimes been encountered when sand bridges or other trash accumulates 
around the locking module, making it difficult or impossible to disengage 
and retrieve the system by pulling on the cable from the surface. The 
pulling force required to break the sand bridge may exceed the tensile 
strength of the CAPS cable, causing it to fail. A system is therefore 
needed that will facilitate the disengagement and separation of the 
locking module from the landing nipple to permit recovery of the locking 
module and the electric submersible pump. 
Another similar problem which is sometimes encountered, is when sand 
bridges or other trash accumulates around, for example, a well tool such 
as a packer, packer seal unit, choke, plug or valve, which prevents normal 
retrieval of the tool. This may occur, for example, when a slickline or 
wireline unit would ordinarily be employed to retrieve the tool, but is 
unable to generate sufficient force to pull the tool loose, due to the 
trash that has accumulated around the tool. In such a situation, an 
expensive and time consuming fishing job may be required, which may 
require the use of a rig and running a string of pipe to depth to retrieve 
the stuck tool. 
SUMMARY OF THE INVENTION 
According to the present invention, apparatus is provided that comprises a 
release mechanism which utilizes hydraulic pressure to overcome the 
resistance caused by sand bridging or the like during recovery of a cable 
or reeled tubing-deployed pumping system. Although the release mechanism 
of the invention is primarily disclosed herein in relation to the 
preferred embodiment of a cable-deployed pumping system, it will be 
apparent that it can be similarly effective when used with a reeled 
tubing-deployed system. The apparatus of the invention is preferably 
adaptable for use in either conventional or inverted electric submersible 
pump applications. 
According to one embodiment of the invention, an emergency release 
mechanism for the locking module discharge head of a cable or reeled 
tubing-deployed, submersible pumping system is provided. The release 
mechanism preferably comprises hydraulically actuated means for forcing 
the locking module discharge head away from the locking module landing 
nipple to permit subsequent withdrawal of the system from a well bore by 
pulling on thecable or reeled tubing. 
According to a preferred embodiment of the invention, a mechanism for 
hydraulically releasing a locking module discharge head from a landing 
nipple is provided that comprises a coaxial support sleeve having a lower 
shoulder which abuts an annular no-go shoulder in the landing nipple. The 
support sleeve is disposed between inner and outer sleeves of the locking 
module discharge head, and shearable means connect the outer sleeve to the 
support sleeve to maintain positional alignment therebetween until 
activation of the release mechanism. A variable volume fluid chamber is 
defined by the space at the top of the support sleeve between the inner 
and outer sleeves. At the top of the variable volume fluid chamber is a 
control fluid inlet port in fluid communication with the surface. The 
variable volume fluid chamber is adapted to be expanded as control fluid 
is pressured into it from the surface, causing the inner and outer sleeves 
to move upward relative to the support sleeve, thereby shearing the 
shearable means and forcing the locking module discharge head to disengage 
and move away from the landing nipple. 
According to another embodiment of the invention, a cable-deployed pumping 
system is provided that comprises a locking module discharge head having a 
hydraulically actuated release mechanism. 
According to another embodiment of the invention, hydraulic release 
apparatus is provided which is useful to retrieve other stuck downhole 
tools. The hydraulic release apparatus includes a piston that is movable 
under the influence of hydraulic pressure to set an anchor slip member 
against the casing to prevent longitudinal movement of the piston in the 
casing against the application of further hydraulic pressure. After the 
anchor slip member is set against the casing, the jack body of the 
hydraulic release apparatus is released, so that application of further 
hydraulic pressure causes the jack body to move longitudinally in the 
casing, thus drawing the stuck tool upwards and freeing it from its stuck 
condition. In order to connect the hydraulic release apparatus to the 
stuck tool, an appropriate latching means is provided with the hydraulic 
release apparatus, which operatively latches onto the stuck tool when the 
hydraulic release apparatus is lowered into position. The latching means 
connects the stuck tool to the jack body, so that longitudinal motion of 
the jack body relative to the locked piston under the influence of 
hydraulic pressure causes the stuck tool to be lifted upward, freeing the 
tool from its stuck condition. Various alternative embodiments of the 
hydraulic release apparatus may be provided to accomplish longitudinal 
manipulation of other downhole tools, for example, to set a casing patch, 
cut tubing or cut the mandrel of a permanent packer for subsequent 
retrieval.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a schematic drawing depicting a modified injector 10 feeding a 
crash-resistant electrical cable 12 from cable reel 14 through window 16 
and wellhead 18 to lower either of two alternative cable-deployed pumping 
systems 20, 22 into a well. Pumping system 20 is a cable-deployed pumping 
system with an inverted pump and pumping system 22 is a cable-deployed 
pumping system with a conventional pump. 
As shown in FIG. 1, inverted pumping system 20 is inserted through 
production tubing 24 disposed inside casing 26. Pumping system 20 
comprises cable anchor assembly 30, electrical penetrator assembly 32, 
motor 34, locking module discharge head 36, locking module landing nipple 
38, and electric submersible pump (ESP) 40. With the exception of 
hydraulic release mechanism 74, which is part of locking module discharge 
head 36 and is described in detail below, all other elements of pumping 
system 20 are previously known to those of ordinary skill in the art and 
are commercially available. Subsurface safety valve 42 and packer 44 are 
installed in production tubing 24 below pump 40. 
In the other embodiment, conventional pumping system 22 is inserted through 
production tubing 46 disposed inside casing 48. Pumping system 22 
comprises cable anchor 50, electrical penetrator 52, locking module 
landing nipple 54, locking module assembly 56, and conventional ESP 
assembly 58. Subsurface safety valve 60 and packer 62 are installed in 
production tubing 46 below ESP assembly 58. 
Although the hydraulic release mechanism of the invention can be utilized 
with either cable-deployed or reeled tubing-deployed pumping systems, and 
with either inverted or conventional ESP systems, for purposes of 
illustration the preferred embodiment of the invention is described herein 
in relation to its use in a cable-deployed, inverted ESP system. Referring 
to FIG. 2, crush-resistant electrical cable 12 (such as CAPS.RTM. cable 
marketed by Kerite Corporation) is used to lower the subsurface equipment 
of pumping system 20 through production tubing 24 inside casing 26. 
Electrical cable 12 is a well known, commercially available product and 
preferably comprises a plurality of insulated electrical conductors and at 
least one support cable disposed inside an insulated, armored sheath. 
Desirably, at least one small-diameter flexible conduit 64 is also present 
inside electrical cable 12 to provide fluid communication between the 
surface and the subsurface equipment suspended from electrical cable 12. 
Cable anchor assembly 30 is adapted to provide a strong mechanical 
connection between the support cable(s) in electrical cable 12 and the 
other subsurface equipment of pumping system 20 that is suspended by 
threaded connections therefrom. Electrical penetrator assembly 32 is 
adapted to connect the electrical conductors passing through electrical 
cable 12 to motor 34. 
As pumping system 20 is lowered through production tubing 24, locking 
module discharge head and collet latch 36 locate, contact and engage 
locking module landing nipple 38, thereby placing pump 40 at the desired 
depth in the well bore and stopping the downward travel of pumping system 
20 through the tubing. When motor 34 and pump 40 are activated from the 
surface, production flow 66 is pulled upward through subsurface safety 
valve 42 into inlet port 68 of pump 40 and thereafter discharged as shown 
by arrows 70 upwardly through production tubing 24. 
During production, sand and other fine particulate matter which is carried 
upward by production flow 66 through pump 40 can settle out and collect 
around locking module discharge head 36. Over time, this sediment can 
harden to form a bridge or other obstruction above locking module 
discharge head 36 that will impede the removal of pumping system 20 from 
the well. When this occurs, the lifting force required to disengage the 
locking module discharge head from the locking module landing nipple may 
exceed the rated tensile strength of electrical cable 12. The use of a 
locking module discharge head 36 having a hydraulic release mechanism as 
disclosed herein will desirably enable the operator to jack the locking 
module discharge head 36 away from the locking module landing nipple 38 a 
sufficient distance to break through the sand bridge or obstruction, after 
which electrical cable 12 can be withdrawn from the well to recover 
cable-deployed pumping system 20. 
As shown in FIG. 3, section 72 is an enlarged cross-sectional elevation 
view (partially broken away) through that portion of production tubing 26, 
locking module discharge head 36 and locking module landing nipple 38 
where release mechanism 74 is located. As locking module discharge head 36 
is lowered into locking module landing nipple 38, lower shoulder 88 of 
support sleeve 86 contacts annular no-go shoulder 90, and collet latch 110 
(better seen in FIG. 2) engages profile 112 in landing nipple 38. Release 
mechanism 74 of the invention is disposed above collet latch 110, the top 
of which is visible near the bottom of FIG. 3. 
Referring to FIGS. 2 and 3, locking module discharge head 36 preferably 
comprises inner sleeve 82, outer sleeve 84 and support sleeve 86. Outer 
sleeve 84 is secured to inner sleeve 82 by weld 87 or other similarly 
effective means, and support sleeve 86 is coaxially aligned between inner 
sleeve 82 and outer sleeve 84 in such manner that inner sleeve 82 and 
outer sleeve 84 slidably engage support sleeve 86. During the installation 
and operation of cable-deployed pumping system 20, support sleeve 86 is 
preferably maintained in fixed relation to inner and outer sleeves 82, 84 
by shearable means such as shear screw 100. Although only one shear screw 
100 is shown in FIG. 3, it will be appreciated that a plurality of 
circumferentially spaced shear screws can be used. Shear screw 100 
prevents inner and outer sleeves 82, 84 of locking module discharge head 
36 from prematurely sliding upwards relative to support sleeve 86 where, 
for example, a hydrostatic head is encountered as locking module discharge 
head 36 is lowered into locking module landing nipple 38. 
Rotational lock key 76 in recess 80 of inner sleeve 82 preferably engages 
recess 78 in landing nipple 38 to restrict rotational motion of locking 
module discharge head 36 relative to landing nipple 38 when, for example, 
electric submersible pump 40 (FIGS. 1 and 2) is activated. This torque 
limiting effect of prong 106 protects shear screw 100 from unintended 
rotational shearing. 
Inner sleeve 82 and outer sleeve 84 cooperate with surface 94 of support 
sleeve 86 to define fluid chamber 92. As shown in FIG. 3, surface 94 is at 
the top of prong 106, which extends upwardly beyond annular top surface 
108 of support sleeve 86 into slot 114 in inner sleeve 82. Slot 114 
thereby helps define fluid chamber 92 and also cooperates with prong 106 
to restrict rotational motion between inner sleeve 82 and support sleeve 
86. Hydraulic fluid is supplied to fluid chamber 92 through inlet port 
102, which preferably communicates with the surface through electrical 
cable 12. Inner and outer O-rings 96, 98, respectively, are preferably 
provided to restrict fluid bypass between the facing, longitudinally 
extending walls of inner and outer sleeves 82, 84 and support sleeve 86. 
Drilled ports 116 are preferably provided to form a fluid leak path 
between bore 118 and annular space 120, thereby avoiding the possibility 
of hydraulic lock-up. 
During installation and use of pumping system 20, the volume of fluid 
chamber 92 remains constant because of the fixed positional relationship 
between inner and outer sleeves 82, 84 and support sleeve 86. Upon 
activation of release mechanism 74, however, pressurized hydraulic fluid 
is pumped from the surface through inlet port 102 into fluid chamber 92. 
When the pressure in fluid chamber 92 becomes sufficiently great to cause 
shear screw 100 to shear, inner sleeve 82 and outer sleeve 84 are forced 
upward relative to support sleeve 86, expanding the volume of fluid 
chamber 92. (Downward movement of support sleeve 86 is precluded by 
annular shoulder 90 of locking module landing nipple 38.) The upwardly 
directed force exerted on surface 104 of inner sleeve 82 from fluid 
chamber 92 is desirably great enough to jack inner sleeve 82 upwards 
relative to locking module landing nipple 38, breaking through any sand 
bridge or other obstruction above locking module discharge head 36 and 
disengaging collet latch 110 from profile 112 in locking module landing 
nipple 38. Pumping system 20 can then be retrieved to the surface by 
pulling on electrical cable 12 without fear of cable failure. 
The hydraulically powered release mechanism is not limited to the 
application of cable deployed, electric, submersible pump assemblies that 
have become stuck in a landing nipple. In general, the mechanism can be 
adapted to any downhole situation where, for example, a retrievable 
packer, packer seal unit, choke, plug or valve has become stock, jammed, 
"sanded in" or for some reason stuck as to prevent normal retrieval, or 
for some other reason longitudinal manipulation of a downhole tool is 
required. Referring to FIGS. 4A-6B, a hydraulic release apparatus 
embodiment, indicated generally as 200, is shown which is suitable for 
retrieving a stuck downhole tool from a well casing 202. In general, 
hydraulic release apparatus 200 can be run into well casing 202 on coil 
tubing or pipe, or lowered at the end of a slickline, not shown in the 
FIGS. As shown in FIGS. 4A-6B, hydraulic release apparatus 200 is deployed 
on the end of coil tubing 204. 
Generally, hydraulic release apparatus 200 includes an elongated 
cylindrical jack body 206, a piston 208, anchor means, illustrated 
generally at 210 and described hereafter, which is movable against the 
casing 202 to restrain longitudinal movement of piston 208 in the casing 
202, and latching means, illustrated generally at 212 and described 
hereafter, which is operatively engageable with the downhole tool in a 
manner permitting the downhole tool to be moved longitudinally or 
manipulated by longitudinal movement of jack body 206 within the casing 
202. Communication of pressurized fluid from the surface or other means to 
hydraulic release apparatus 200 to manipulate jack body 206, piston 208, 
and set anchor means 210 against casing 202 is provided via coil tubing 
204, which is threadedly engaged in an axial bore 213 located in the top 
portion of jack body 206. As shown, pipe threads may be employed to 
prevent leakage between jack body 206 and coil tubing 204, although other 
suitable means may also be utilized to prevent leakage therebetween. In 
this embodiment, coil tubing 204 provides locating means for lowering and 
positioning hydraulic release apparatus 200 in the well casing 202 
adjacent the stuck tool in a suitable position wherein latching means, 
described hereafter, is operatively engaged with the stuck tool for 
movement therewith when jack body 206 is moved longitudinally relative to 
piston 208 to loosen the stuck tool for subsequent retrieval from casing 
202, as described hereafter. 
In the unshown slickline embodiment, a control line, not shown in the 
FIGS., may connect to the jack body to communicate pressurized fluid to 
the hydraulic release apparatus. In this embodiment, the slickline 
provides locating means for lowering and positioning the slickline 
hydraulic release apparatus in the well casing adjacent the stuck tool in 
a suitable position wherein latching means, described hereafter, is 
likewise operatively engaged with the stuck tool for movement therewith 
when the jack body is moved longitudinally relative to the piston to 
loosen the stuck tool for subsequent retrieval from the casing, as 
described hereafter. To communicate pressurized fluid to the jack body, 
the control line may be threadedly engaged in a bore in the upper portion 
of the jack body. Pipe threads may likewise be provided to prevent leakage 
between the jack body and the control line. Otherwise, the slickline 
embodiment of the hydraulic release apparatus is similar to hydraulic 
release apparatus 200. In another alternative embodiment the jack body may 
be provided with a fluid reservoir, and an electric pump may be provided 
which communicates pressurized fluid from the fluid reservoir to operate 
the hydraulic release apparatus. A source of power to operate the electric 
pump may be provided by electric line or a downhole battery pack, which 
may be mounted on the jack body. 
As illustrated in FIGS. 4A-4B, piston 208 may be provided in the form of a 
sleeve shaped member, which is received in a ring shaped, elongated bore 
214 in jack body 206. As illustrated in FIG. 4A, bore 214 may be provided 
by forming jack body 206 with a narrowed cylindrical neck portion 216, 
which is concentrically received within an elongated, cylindrical sleeve 
218, and radially spaced therefrom to form bore 214. Cylindrical sleeve 
218 may be received in an annular recess 220 concentrically surrounding 
the main portion of jack body 206 at its juncture with neck portion 216, 
and attached thereto by suitable means such as welding or threads. A seal 
element, not shown in the FIGS., may be provided to prevent fluid leakage 
between cylindrical sleeve 218 and jack body 206. 
Piston 208 is movable in bore 214 from a first position, as shown in FIG. 
4A, to a second position in body 206, as shown in FIG. 6A. One or more 
shearable elements in the form of shear screws or pins 222 releasably 
engage piston 208 to jack body 206 until after hydraulic release apparatus 
200 has reached the desired downhole location. Shear pins 222 join piston 
208 and jack body 206 to retain piston 208 in its first position against 
inadvertent increases in fluid pressure. The predetermined value at which 
shear pins 222 release or shear may be, for example, 1,000 pounds-force. 
A pair of annular elastomeric seals 224 carried in annular grooves on 
opposed surfaces of neck portion 216 and cylindrical sleeve 218 sealingly 
engage piston 208 and form a movable fluid barrier between cylindrical 
sleeve 218, piston 208 and neck portion 216. Piston 208 and elastomeric 
seals 224 enclose a variable volume fluid chamber 226, which is provided 
by the portion of bore 214 contained between piston 208, sleeve 218 and 
neck portion 216. As may be appreciated, the number of seal elements or 
other seal means between piston 208, neck portion 216 and cylindrical 
sleeve 218 which enclose fluid chamber 226 may number more or less. 
One or more ports 228 extend through jack body 206 and connect with bore 
213 and fluid chamber 226 to communicate pressurized fluid from the 
interior of coil tubing 204 to fluid chamber 226 to move piston 208 to an 
intermediate anchored position between its first and second positions, as 
illustrated in FIG. 5, to set anchor means 210 against casing 202 and 
thereafter act against jack body 206 to move jack body 206 longitudinally 
in casing 202 relative to piston 208 until piston 208 assumes its second 
position in jack body 206, as shown in FIG. 6A. In order to prevent 
pressure build up in the area enclosed between latching means 212 and jack 
body 206, neck portion 216 may be provided with a counterbore 230 which 
communicates with the interior of the casing 202 via one or more ports 232 
to prevent pressure buildup. In the slickline embodiment, one or more 
ports likewise extend through the jack body to connect with the bore in 
which the control line is connected and the fluid chamber to communicate 
pressurized fluid from the interior of the control line to the fluid 
chamber to move the piston to a similar intermediate position as 
illustrated in FIG. 5 to set anchor means 210 against the casing and 
thereafter act against the jack body to move the jack body longitudinally 
in the casing until the piston assumes it second position in the jack 
body, similar to FIG. 6A. 
Referring to FIG. 4A, anchor means 210 may be provided in the form of an 
expandable C-shaped anchor slip member 234, a cylindrically shaped wedge 
member 236, and a cylindrically shaped slip support 238. Anchor slip 
member 234 is carried on neck portion 216 between wedge member 236 and 
slip support 238. Slip member 234 may be equipped with teeth 240 on their 
outer surfaces for gripping casing 202 to hold piston 208 in a fixed 
position thereto when set against casing 202. Alternatively, for example, 
slip member 234 may be segmented. 
Wedge member 236 may be attached to piston 208 for movement therewith 
toward slip support 238, which may be attached to neck portion 216 so that 
anchor slip member 234 ramps over wedge member 236 from a first recessed 
run-in or retrocted configuration, as shown in FIG. 4A, and is expanded 
radially outward to a second anchored configuration suitable for gripping 
engagement against bore 242 of casing 202, as shown in FIG. 5. Because 
wedge member 236 is arranged to further wedge or ramp under complimentary 
shaped anchor slip member 234 under the influence of further fluid 
pressure applied in fluid chamber 226 against piston 208, once anchor slip 
member 234 is ramped outwardly against casing bore 242, piston 208 is 
locked in position in casing 202, and prevented from moving downward in 
casing 202 under the influence of further hydraulic pressure. 
One or more shear pins 244 releasably engage slip support 238 to neck 
portion 216 of jack body 206 until anchor slip member 234 is ramped to its 
second position, grippingly engaged against the bore 242 of casing 202. 
Thereafter, at a predetermined fluid pressure, pins 244 shear, releasing 
jack body 206 for longitudinal motion relative to anchor slip member 234 
and piston 208, which remains locked in position in casing 202 by the 
wedging action between anchor slip member 234 and slip support 238 under 
the influence of fluid pressure in fluid chamber 226 acting downward on 
piston 208. Once pins 244 shear, releasing jack body 206 from its juncture 
with piston 208, fluid pressure acting against an annular shoulder 246 on 
jack body 206 causes jack body 206 to move longitudinally upward in casing 
202 relative to locked piston 208 and anchor slip member 234, until piston 
208 assumes its second position in jack body 206, as shown in FIG. 6A. As 
may be appreciated a lug arrangement or complementary shoulder portions, 
not shown in the FIGS., may, for example, be provided to retain piston 208 
in bore 214. 
Referring again to FIG. 4A, latching means 212 may be provided in the form 
of a pulling device 248, which is suitable for pulling and releasing a 
downhole tool such as a retrievable packer 250 when jack body 206 is moved 
longitudinally upward in casing 202. Pulling device 248 includes a tubular 
body 252 which extends concentrically downward from neck portion 216 of 
jack body 206, and is attached thereto by suitable means such as threads 
for longitudinal motion therewith. Tubular body 252 may be provided with 
one or more J-shaped slots 254 therein which engage with lugs 256 on the 
top sub of packer 250 when hydraulic release apparatus 200 is lowered in 
casing 202 to depth and positioned with the lower end of tubular body 252 
inserted into the bore 257 of packer 250. To aid in insertion of the lower 
end of tubular body 252 into bore 257 of packer 250, the lower end of 
tubular body 252 may have a slanted portion 258, as shown in FIG. 4B. 
With lugs 256 engaged in J-shaped slots 254, upward motion of jack body 206 
relative to piston 208 under the influence of hydraulic pressure pulls the 
upper end of packer 250 upward, thus freeing packer 250 from its stuck 
position in casing 202. Upward motion of the upper end of packer 250 pulls 
the packer's upper slip 260 upward and off upper ramp 262, allowing the 
packer seal assembly 264 to relax inward. As packer 250 moves upward in 
casing 202, its lower slip 266 moves downward and off lower ramp 268, as 
shown in FIG. 6B, thus freeing packer 250 from its set condition for 
subsequent retrieval from casing 202. 
Latching means 212 may also be in the form of a ratcheting, latchable head, 
not shown in the FIGS. Conventionally, the ratcheting, latchable head may 
be provided with a threaded collet portion which allows the ratcheting, 
latchable head to ratchet downward over a threaded portion on the upper 
end of a downhole tool such as a retrievable packer while preventing 
ratcheting movement in the opposite direction, thus allowing operative 
engagement between the ratchcling, latchable head and the tool to permit 
the downhole tool to be moved longitudinally or lifted loose when jack 
body 206 is moved longitudinally relative to piston 208. Of course, it is 
also within the scope of the invention that other latching means may also 
be utilized to latch on to the downhole tool such that longitudinal 
movement of jack body 206 in casing 202 causes the downhole tool to move 
longitudinally or to be freed for retrieval. For example, the latching 
means may latch onto a casing patch, such that the casing patch can be 
moved longitudinally upward to set the patch, thus repairing damaged 
casing. In another example, the latching means may include a 
longitudinally movable cutting tool, which expands radially outward when 
moved longitudinally upward to cut a tubular member or the mandrel of a 
permanent packer for retrieval. 
Hereafter, the operation of hydraulic release apparatus 200, coil tubing 
204 and latching means in the form of pulling device 248, which is 
suitable for retrieving a stuck retrievable packer 250, is described. In 
operation, hydraulic release apparatus 200 is run into well casing 202 by 
unfeeling coil tubing 204, and positioned in casing 202 such that its 
latching means in the form of pulling device 248 operatively engages the 
stuck packer 250. Shear pins 222 prevent inadvertent movement of piston 
208 relative to jack body 206 while hydraulic release apparatus 200 is 
being run into casing 202 and positioned to operatively engage packer 250. 
Slanted portion 258 assists in locating tubular body 252 in the entrance 
to bore 257 of packer 250 such that further downward movement of hydraulic 
release apparatus 200, and its attached pulling device 248 causes J-shaped 
slots 254 to engage lugs 256 on the top sub of packer 250, thus 
operatively attaching packer 250 to pulling device 248 for longitudinal 
movement therewith. 
At this point, pressurized fluid applied through coil tubing 204 to fluid 
chamber 226 to act against piston 208, shears shear pins 222 and causes 
piston 208 to move downward to its intermediate position between its first 
and second positions, as shown in FIG. 5. As piston 208 moves downward to 
its intermediate position, wedge member 236 moves downward and under 
anchor slip member 234, causing anchor slip member 234 to ramp radially 
outward against bore 242 of casing 202. Continued application of hydraulic 
pressure causes teeth 240 to grippingly engage casing bore 242, locking 
piston 208 in position within casing bore 242 and restraining further 
longitudinal movement of piston 208 in casing 202. 
Once anchor slip member 234 is set against grippingly against casing bore 
242, further application of increased hydraulic pressure causes shear pins 
244 to shear, releasing jack body 206 for longitudinal movement in casing 
202 relative to locked piston 208 and anchor slip member 234. In order to 
assure that slip member 234 is set grippingly against casing 242, the 
predetermined value at which shear pins 244 shear or release, is such to 
assure that anchor slip member 234 is set grippingly against casing bore 
242 to prevent slippage of anchor slip member 234 against the application 
of further increased hydraulic pressure necessary to free the stuck tool. 
Once shear pins 244 shear, further application of hydraulic pressure 
attempts to force piston 208 downward, which remains locked in position in 
casing 202 by the wedging action between anchor slip member 234 and 
complimentary shaped slip support 238. After shear pins 244 shear, further 
application of hydraulic pressure acts against shoulder 246 of jack body 
206, causing jack body 206 to move longitudinally upward in casing 202 
relative to locked piston 208, until piston 208 assumes its second 
position in jack body 206, as shown in FIG. 6A. 
With lugs 256 engaged in J-shaped slots 254, upward motion of jack body 206 
relative to locked piston 208 under the influence of hydraulic pressure 
pulls the upper end of packer 250 upward, thus freeing packer 250 from its 
stuck position in the sand bridge or trash which has accumulated in casing 
202 adjacent the upper end of packer 250. Upward motion of the upper end 
of packer 250 pulls the packer's upper slip 260 upward and off upper ramp 
262, allowing the packer seal assembly 264 to relax inward. As packer 250 
moves upward in casing 202, freed from the sand bridge or trash which has 
accumulated around its upper end, its lower slip 266 moves downward and 
off lower ramp 268, as shown in FIG. 6B, allowing packer 250 to be moved 
longitudinally upward in casing 202, thus freeing packer 250 from its set 
condition for removal from casing 202. Thereafter, the hydraulic pressure 
may be released, allowing wedge member 236 to recede from under anchor 
slip member 234 as hydraulic release apparatus 200 is withdrawn from 
casing 202, allowing anchor slip member 234 to collapse radially inward. 
Hydraulic release apparatus 200, coil tubing 204 and packer 250 may now be 
removed as a unit from casing 202 by rewinding coil tubing 204. 
The operation of the slickline hydraulic release apparatus is similar to 
the above method of operation, except that the slickline is employed to 
position the hydraulic release apparatus for operative engagement with the 
stuck tool. 
Other alterations and modifications of the invention will become apparent 
to those of ordinary skill in the art upon reading the present disclosure, 
and it is intended that the scope of the invention disclosed herein be 
limited only by the broadest interpretation of the appended claims to 
which the inventors are legally entitled.