Method and apparatus for jarring

An apparatus and method for delivering a jarring action to an object in a well bore is disclosed. Generally, the apparatus comprises a cylindrical housing, with the cylindrical housing being connected to the stuck object; and, a power mandrel disposed within said cylindrical housing, with the power mandrel being threadedly connected to a work string. The invention also includes a latch member adapted to the housing, and a collet member having an end engageable with the latch. A conical member is adapted to set, reset and unlatch the engageable end of the collet. Also included will be an activation piston cooperating with the conical member.

In order to produce hydrocarbons, a well bore is drilled until a 
subterranean reservoir is encountered. Once the drilling of the well bore 
has been completed, a casing string may be run into the well bore, and 
then cemented into place. As is understood by those of ordinary skill in 
the art, the subterranean reservoir can then be perforated to allow 
communication between the reservoir and the casing. Thereafter, the well 
may be completed, for instance, with the placement of gravel pack and a 
gravel pack screen. The well is then capable of producing the 
hydrocarbons. 
For the drilling and completing of the well bores to the hydrocarbon 
reservoirs, different types of drill and completion strings may be 
employed. Historically, a drill string made up of a series of coupled 
drill pipe has been employed for rotary drilling. Recently, coiled tubing 
has been utilized for both the drilling and completion phase. The coiled 
tubing is generally of a smaller diameter tubular as compared to drill 
pipe, and moreover, is continuous e.g. lacks interconnecting tool joints. 
It should also be understood that the invention described herein is 
applicable to drill pipe, coiled tubing and other types of work strings 
such as wireline and electric line. 
During the course of drilling, completing and producing the hydrocarbon 
reservoir, objects may become stuck within the well bore. Stuck objects 
within the well bores are sometimes referred to as "fish". In order to 
loosen these objects, jars have been developed that have the effect of 
providing a jolting impact to the object. Moreover, many wells being 
drilled include highly deviated and horizontal wells. During the course of 
drilling these wells, jarring impacts to the bottom hole assembly may be 
necessary in order to release the objects. Also, it may be necessary to 
set or unseat certain bottom hole assembly devices by providing jarring 
impacts. The invention described herein is applicable to all the above 
situations. 
Several prior art jars have been developed. One of the first jars invented 
for use in well bores was U.S. Pat. No. 2,122,751 to J. T. Phipps in 1938. 
Other prior art devices include U.S. Pat. No. 3,203,482 to C. R. Lyles in 
1965, U.S. Pat. No. 4,333,542 to W. T. Taylor in 1982, and U.S. Pat. No. 
5,139,086 to J. M. Griffith. 
Despite these prior art devices, problems exist. The prior art devices have 
been bulky and require large outer diameter housings in order to encase 
the necessary components. Thus, as well bores become longer and more 
deviated, the need for small diameter tools is very great. Also, the prior 
art devices suffer from not being able to accurately and dependably 
deliver the force required. This can result from the type of spring 
employed in many prior art devices. For instance, frusto-conical bellville 
washers can flatten due to use, and the amount of force required to 
activate the jar can lessens with repeated use. Also, coiled springs can 
break, completely disrupting the operation of the jar. 
Therefore, there is a need for a jar that will function properly and 
effectively in small inner diameter holes. Also, there is a need for a jar 
that will have dependable and reliable predetermined amount of force that 
will activate the jar to cause an impact force on an object in the well. 
SUMMARY OF THE INVENTION 
A device to jar an object within a well bore is disclosed. Generally the 
device comprises a housing having a latch member and a anvil along with a 
power mandrel slidably disposed within said housing, the mandrel having a 
hammer. Also included will be engaging means for engaging and releasing 
the hammer for impact against the anvil from a latched position and 
operating means for resetting the hammer into the latched position. The 
device may also include biasing means for biasing said engaging means in a 
first direction. In one embodiment, a tension means for adjusting the 
tension in the biasing means is included. 
In the preferred embodiment, the power mandrel also includes a spring 
adapted to urge the engaging means in a first direction; and, an end 
adapted to contact the operating means. The engaging means may comprise a 
collet member having a first end and a second end with the first end being 
disposed about the first portion of the power mandrel and a second end 
having protuberances cooperating with the operating means; a conical 
member disposed within the housing and set apart from the power mandrel; a 
locking leg adapted for cooperation with the conical member; and, detent 
means for locking the locking leg with the conical member. 
In the preferred embodiment, the operating means will have an activation 
piston disposed within the conical member and wherein the activation 
piston contains a detent cavity adapted to cooperate with the detent 
means. 
The apparatus may also contain a first spring adapted for urging the 
activation piston in a first position, and a second spring adapted for 
urging the locking member in a first direction. The housing may contain a 
window opening, and the tension means may comprise a threaded member 
adapted to engage the locking leg so that as the threaded member is 
rotated, the tension in the biasing means is adjusted. 
A method of providing a jarring force to an object in a well bore is also 
disclosed. Generally, the method comprises the steps of lowering on a work 
string the novel jar disclosed herein. Generally, the jar contains a 
housing; a latch member adapted to the housing; a mandrel, slidably 
disposed within the housing and being connected to the work string; a 
collet member having a first end disposed about the mandrel and a second 
end engagable with the latch; a conical member adapted to engage the 
second engagable end of the collet member; a leg extension member 
selectively attachable to the conical member; and, an activation piston 
cooperating with the conical member and the leg extension. 
The method further includes exerting a pulling force on the mandrel with 
the work string, which in turn will engage the collet engaging end against 
the latch. This will force the conical member in a downward direction 
relative to the latch. After an adequate amount of force has been applied, 
the collet will be released from engagement from the latch. The hammer 
will be simultaneously released to impact against the anvil. 
The method may further comprise the steps of exerting a pushing force on 
the mandrel with the work string so that the second end of the collet 
engages the conical member and the latch member. Next, the conical member 
is moved in a downward direction relative to the latch which in effect 
will reset the second end of the collet against the latch member. 
In one embodiment, the object is a stuck object within the well bore and 
the work string is a coiled tubing string. In this case, the method 
further comprises the steps of exerting a pulling force on the mandrel 
with the coiled tubing string. This will engage the collet engaging end 
against the latch. The continued pulling will force the conical member in 
a downward direction relative to the latch which in turn will release the 
collet engaging end from the latch. Thereafter, the hammer will travel 
instantaneously and impact the anvil so that a jarring action is 
transferred to the stuck object. 
A feature of the present invention includes a latch mechanism that is on 
the housing and a collet that cooperates with the latch. Another feature 
includes a conical member that is adapted to engage with the collet. Yet 
another feature includes an activation piston adapted to release the 
conical member. 
Another feature includes the detent means for locking the locking leg with 
the conical member. Still yet another feature includes a mandrel and an 
activation piston that are detached from each other and longitudinal 
movement of the mandrel is necessary to activate the piston. 
An advantage of the invention is the option of manufacturing smaller outer 
diameter tools for use in small inner diameter well bores. Another 
advantage is that the jar may be set and reset (after firing) as often as 
desired by the operator. Another advantage is that resetting is more 
reliable than prior art designs. Yet another advantage is that the jar 
will function in highly deviated and horizontal wells. Still yet another 
advantage is that the tension in the biasing means may be adjusted at the 
rig site. 
Another advantage of the present invention includes having a more 
predictable force requirement for detaching the collet end from the catch 
located on the housing. Another advantage includes being able to reset 
multiple times without fatigue of the biasing means. Another advantage is 
the minimum number of parts that make-up the invention thereby making the 
invention an uncomplicated and workable invention that requires little 
field maintenance. Still yet another advantage is the stroke length of the 
jar is twenty inches.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a typical wire line unit 2 is shown operating in a 
well bore 4, which in the figure shown is a casing string as will be 
appreciated by those of ordinary skill in the art. The well bore 4 will 
intersect an subterranean reservoir 6 that will contain hydrocarbons. 
The wire line unit 2 will have extending therefrom a work string 8 that 
will have attached thereto a bottom hole assembly 10. As seen in FIG. 1, 
the bottom hole assembly has attached thereto the jar apparatus 12 of the 
present invention. The jar apparatus will in turn be connected to an 
object, which may be a stuck object such as a packer. It should be 
understood that the apparatus of the present invention is applicable to 
various types of work strings such as conventional drill pipe, as well as 
snubbing tubing, wireline, coiled tubing and electric line. Moreover, the 
apparatus may be used to provide a jarring impact to objects such as 
packers and setting tools. 
Referring now to FIGS. 2A-2D, the preferred embodiment of the present 
invention will now be described. While the invention is applicable to 
various work strings such as coiled tubing, the embodiment shown is 
specially adaptable to wire line. The apparatus will require only minor 
modifications from the embodiment shown in FIGS. 2A-2C for through tubing 
use such as coiled tubing by providing a bore hole through the inner 
diameter of the mandrel. 
Referring to FIG. 2A, the cylindrical housing 20 comprises a first section 
22 that is a fishing neck 22 that has a recessed surface 24, that leads to 
cylindrical surface 26, with cylindrical surface terminating at radial 
surface 28. The radial surface extends to the cylindrical surface 30, with 
the surface 30 having contained thereon external thread means 32 and 
concluding on anvil shoulder 33. The first section 20 contains an inner 
diameter portion 34. 
The second section 36 of the cylindrical housing 20 will now be described. 
A connecting sub for connecting section 22 with section 36 is not shown. 
The second section 36 has a cylindrical outer body 38 that extends to the 
generally radial surface 40 which in turn extends to the internal thread 
means 42, with the thread means 42 stretching to the inner diameter bore 
44. The bore 44 will through the latch means 45a. The latch means 45a 
comprises a first angled surface 45b that in turn leads to the 
circumference point 45c which then extends to chamfered surface 45d. The 
bore 44 continues thereafter. 
The third section 54 of the cylindrical housing 20, as seen in FIG. 2C, 
includes and outer surface 56 that terminates at the radial shoulder 58, 
that in turn extends to internal threads 60. The threads 60 stretches to 
inner bore 62. Generally, the thread means 60 may be attached to the fish. 
Other means of attaching to the fish are available such as over-shots. 
The power mandrel, seen generally at 82 in FIG. 2A, will now be described. 
The power mandrel 80 will have external thread means 82 at the first end 
of the mandrel 80, with the external thread means 82 that in turn extends 
to the cylindrical surface 84. The surface 84 extends to radial shoulder 
86 (known as the hammer) that in turn terminates at the cylindrical 
surface 88 which in turn terminates at the radial shoulder 90 that extends 
to the cylindrical surface 92. 
The surface 88 will conclude at the radial surface 90 with the radial 
surface 90 containing a cavity 96, with the cavity 96 containing internal 
thread means 98 that will be threadedly connected to the operator mandrel 
100. The operator mandrel 100 will have disposed about it a collet member 
102 that makes up a part of the attachment means for attaching the 
operator mandrel 100 to the cylindrical housing body 20. 
The operator mandrel 100 generally comprises external thread means 104 that 
extends to the outer cylindrical surface 106 which in turn terminates at 
the shoulder 108. The shoulder 108 extends to the cylindrical surface 110 
which in turn extends to the shoulder 112 which stretches to the 
cylindrical surface 114 which terminates at the end 116. 
The collet member 102 generally comprises a top ring member 118 that 
includes a cylindrical outer surface 120 that extends to the radial 
surface 122 which in turn leads to the inner bore surface 124 that 
contains the shoulder 126. The shoulder 126 and shoulder 108 of the 
mandrel 100 will abut one another due to the collet spring 128. The 
shoulder terminates at the second inner bore 130 which then leads to the 
radial surface 132. The ring member 118 will have the collet tines 134, 
with the individual tines 134 stretching to the protuberance end 136. As 
shown, the protuberance has an angled surface 138 whereas the posterior 
surface 140 is more rounded. The surface 136 and 138 aid in the release 
and resetting of the collet member 102 as will be more fully explained 
later in the application. 
The collet member 102 will be operatively associated with the engaging 
means, seen generally at 150, for setting, resetting and releasing said 
collet member 102. Generally, the engaging means 150 comprises the collet 
102, the conical member 152, the cone extension 154, and the detent means 
163, 228. The operating means, seen generally at 156, for selectively 
detaching said conical member 152 with the leg extension 154. The 
operating means 156, which cooperates with the engaging means 150 as will 
be more fully set out, includes an activation piston 156 disposed with the 
conical member, and a detent cavity 222. 
The conical member 152 will have an upper unit including outer conical 
surface 158 with the top end 159 that extends to the external thread means 
160 that extends to the flat surface 161 and first inner bore surface 162 
which in turn leads to the second inner bore surface 164. The second inner 
bore surface 164 terminates at the radial shoulder 166 which then extends 
to the third inner bore surface 168. The lower unit of the conical member 
152 includes internal thread means 170 that stretches to the conical 
surface 172 which in turn leads to the cylindrical surface 174. The 
surface 174 terminates at the radial surface 176 which then leads to the 
bore surface 178, with the bore surface 178 leading to the inner radial 
shoulder 180 which in turn extends to the inner bore surface 182. 
The leg extension 154 contains an upper unit and a lower unit wherein the 
upper unit contains an outer cylindrical surface 184 that contains the 
aperture 186. The cylindrical surface 184 extends to the radial shoulder 
188 which then leads to the cylindrical surface 190 which then advances to 
the shoulder 192, surface 194 and radial surface 196. Extending radially 
inward will be the internal threads 198 that then advance to the smooth 
inner bore 200, and flat surface 202. 
The lower unit of the leg extension 154 will include a first outer 
cylindrical surface 204 that extends to the external threads 206 on one 
side and to the radial shoulder 208 which in turn leads to the second 
outer cylindrical surface 210. Extending radially inward will be the flat 
surface 212 which in turn leads to the inner bore 214. 
The operating means 156 normally comprises an activation piston that 
contains a first outer cylindrical surface 216 that extends to the radial 
shoulder 218 that in turn extends to the second outer cylindrical surface 
220. The second outer surface 220 will contain therein a detent means 222 
that contain angled sides 224, 226 for cooperation with the detent members 
228 which in the illustration is locking balls 228. The piston 156 has a 
first end 230 and second end 232. As seen in FIG. 2C, a biasing means 234 
for biasing the leg extension 154 is disposed about the leg extension 154 
and in particular the cylindrical surface 204. 
The apparatus will also contain tension means for adjusting the tension in 
the biasing means 234, as seen in FIG. 7. The cylindrical housing 38 will 
have a window 240 cut therethrough. An adjusting tension nut 242 will be 
disposed about the leg extension 154 and in particular the cylindrical 
surface 204. The tension nut 242 will have at the outer cylindrical 
surface external thread means 244 that will cooperate with the internal 
thread means 42 of the outer housing 38. The tension nut 242 will have a 
series of grooves formed on the outer cylindrical surface. Thus, in use, 
the operator will use a key which will be stuck through the window 240 and 
into the cavities 260. The key is inserted into the groove and turned; 
therefore, with right hand rotation the nut will travel longitudinally 
upward relative to the operating means 150 so that the tension in the 
biasing means 234 is increased. Left hand rotation of the tension nut 242 
by means of the key will cause the tension nut 242 to travel downward 
relative to the operating means 150 so that tension in the biasing means 
234 is decreased. 
The apparatus herein disclosed also contains a cone spring means 250 for 
urging the conical member 152 longitudinally upward relative to the collet 
member 102. Also included will be the operating means 156 release spring 
252 which will engage the second end 232 and urge the detaching means 156 
upward relative to the leg extension member 154. 
The operation of the present jar apparatus 12 will now be described. 
Referring to FIGS. 2A-2D, the jar is in the extended or open position 
which represents the state after the jar 12 has been allowed to release. 
Thus, the mandrel 80 and in turn the operator mandrel 100 are lowered 
slowly. This will also have the effect of lowering the collet member 102 
since the collet spring 128 will act to urge the ring member 118 down. The 
lowering process will continue until the protuberance end 136 of the 
collet member 102 makes contact with the outer conical surface 158 and the 
latch means 45a. Note the posterior surface 140 makes contact with the 
conical surface 158; this is important since by changing the angles of 
both surfaces 140 and 158, the amount of force to re-latch will be 
effected. 
Additional lowering of the jar 12 and in particular the operator mandrel 
100, collet member 102, and collet tines 134 will cause the collet spring 
128 to compress. Also, at this point the downward movement of the tines 
134 has effectively stopped. Nevertheless, due to the novel design the 
operator mandrel 100 and end 116 continue longitudinally downward relative 
to the engaging means 150. This downward movement will continue until the 
end 116 of the operator mandrel 100 contacts the operating means 156, and 
in particular, the activation piston end 230. Further downward movement of 
the operator mandrel 100 will over power the release spring 252 so that 
the detaching means 156 continues its downward movement. Note that the 
detent means cavity 222 is also moving downward. 
As seen in FIG. 4B, when the end 116 and the activation piston end 230 have 
moved sufficiently downward so that the end 116 contacts the end 159 of 
the operating means 150, the detent members 228 are free to move into the 
detent means cavity 222. The operating means 150, and in particular the 
conical member 152 are release in order to move down against the cone 
spring 250. As seen in FIG. 4B, both the cone spring 250 and release 
spring 252 are compressed. 
Thereafter, the operating mandrel 100, collet spring 128, operating means 
156, conical member 152 and the cone extension 154 will all move down as a 
unit until there is enough space between the latch means 45a, and in 
particular the circumference point 45c, and the outer conical surface 158 
as illustrated in FIGS. 5A-5C to enable the protuberance end 136 to get 
below the angled surface 45c of the latch means 45a. Also, the detent 
members 228 have fallen into place within the groove 163 so that the cone 
member and cone extension 154 are again locked together. In the position 
shown in FIG. 5B, the jar apparatus 12 is in the latched position. 
The cone extension 154 will prevent the upward movement of the conical 
member 152 which is tensioned by the cone spring 250 and by the shoulder 
208 of the cone extension acting against the shoulder 260 of the bottom 
sub of the housing 54. 
In order to jar an object in the well bore, the operator would begin 
pulling on the work string which in turn cause the operating mandrel 100 
to also pull on the collet tines 134. Once a predetermined force is 
pulled, the protuberance end 136 will become disengaged with the latch 
means 45a allowing the hammer 86 to travel rapidly and strike the anvil 33 
thereby delivering a jarring impact to the object in the well bore. 
Thereafter, the jar 12 may be re-latched as previously explained. 
The tension exerted against the conical member 152 by the biasing means 234 
is controlled by the tension nut 242. The nut 242 is adjusted by insertion 
of a bar or rod into cavities 260 drilled in the side of the nut 242 and 
turned clockwise in the window 240 milled in the lower housing 5 as 
illustrated in FIG. 7. 
Changes and modifications in the specifically described embodiments can be 
carried out without departing from the scope of the invention which is 
intended to be limited only by the scope of the appended claims.