U.S. patent application number 13/152484 was filed with the patent office on 2011-12-08 for selective control of charging, firing, amount of force, and/or direction of force of one or more downhole jars.
This patent application is currently assigned to BP EXPLORATION OPERATING COMPANY LIMITED. Invention is credited to Mark William Alberty, Nigel Last, Warren J. Winters.
Application Number | 20110297380 13/152484 |
Document ID | / |
Family ID | 44626947 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110297380 |
Kind Code |
A1 |
Alberty; Mark William ; et
al. |
December 8, 2011 |
SELECTIVE CONTROL OF CHARGING, FIRING, AMOUNT OF FORCE, AND/OR
DIRECTION OF FORCE OF ONE OR MORE DOWNHOLE JARS
Abstract
Methods of jarring include communicating between a surface
command device and jars in a drill string, the drill string
composed of spaced apart jars positioned in a corresponding
plurality of wired and/or wireless pipe sections. The methods
include selectively controlling charging, firing, amount of force,
and/or direction of force of the jars using digitally-controlled
surface command devices. One method includes firing a sub-set or
all of the jars in a controlled manner and determining depth of a
stuck drill string section through analysis of behavior or
performance of the fired jars. Other methods include subsequently
firing one or more of the jars again below the stuck drill string
section. Other methods include selectively firing, using digital
signals from the surface command device, jars sequenced in time so
that their forces meet in a constructive or destructive manner at a
preselected point in the drill string.
Inventors: |
Alberty; Mark William;
(Houston, TX) ; Winters; Warren J.; (Cypress,
TX) ; Last; Nigel; (Weybridge, GB) |
Assignee: |
; BP EXPLORATION OPERATING COMPANY
LIMITED
Sunbury on Thames
TX
BP CORPORATION NORTH AMERICA INC.
Houston
|
Family ID: |
44626947 |
Appl. No.: |
13/152484 |
Filed: |
June 3, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61351177 |
Jun 3, 2010 |
|
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|
Current U.S.
Class: |
166/301 |
Current CPC
Class: |
E21B 31/113
20130101 |
Class at
Publication: |
166/301 |
International
Class: |
E21B 31/107 20060101
E21B031/107; E21B 31/113 20060101 E21B031/113 |
Claims
1. A method of jarring comprising: communicating between a surface
command device and communication components in two or more jars of
a drill string, the drill string comprising a plurality of spaced
jars positioned in a corresponding plurality of wired pipe
sections; and selectively controlling at least one of charging,
firing, amount of force, and direction of force, and two or more of
these parameters, of two or more of the jars via at least one of
the surface command devices.
2. The method of claim 1, further comprising firing a sub-set or
all of the jars in a controlled manner and determining depth of a
stuck drill string section through analysis of behavior or
performance of the fired jars.
3. The method of claim 2, further comprising subsequently firing
one or more of the jars again below the stuck drill string
section.
4. The method of claim 1, further comprising selectively firing,
using a digital signal from the surface command device, two or more
jars sequenced in time so that their forces meet in a constructive
manner at a preselected point in the drill string.
5. The method of claim 1, further comprising selectively firing,
using a digital signal from the surface command device, two or more
jars sequenced in time so that their forces meet in a destructive
manner at a preselected point in the drill string.
6. The method of claim 1, further comprising selecting from the
surface command device the direction two or more of the jars will
fire sequentially, up the drill string or down the drill
string.
7. The method of claim 1, wherein selectively controlling comprises
digitally selectively controlling one or more of the jars from the
surface command device.
8. The method of claim 7, further comprising generating a model of
the drill string, including the jars, and digitally controlling the
cocking, firing, direction, and/or amount of force used in selected
jars according to the generated model.
9. The method of claim 1, further comprising charging one or more
of the jars from the surface command device by actuating a
digitally-controlled valve in the jar which directs hydraulic
pressure from within the drill string to charge the jar.
10. The method of claim 1, wherein the communication components
comprise a wireless device in one or more of the jars, the method
further comprising sending a wireless electromagnetic signal from
the surface command device to two or more of the jars, or from two
or more jars to the surface command device.
11. The method of claim 1, wherein the communication components
comprise wiring in two or more of the jars, the method further
comprising sending an electromagnetic signal from the surface
command device to two or more of the jars through wired connections
in the drill string, or from two or more of the jars to the surface
command device.
12. A method of freeing stuck components of a drill string in a
subterranean borehole, the method comprising: drilling a borehole
using the drill string, the drill string comprising a plurality of
spaced apart jars and a plurality of wired drill pipe sections, the
drill pipe section and jars each comprising electromagnetic
components allowing communication at least between the jars and a
surface command device; communicating between the surface command
device and the communication components in two or more of the jars;
and selectively controlling at least one of charging, firing,
amount of force, and direction of force, of two or more of the jars
via the surface command device.
13. The method of claim 12, further comprising firing a sub-set or
all of the jars in a controlled manner and determining depth of a
stuck drill string section through analysis of behavior or
performance of the fired jars.
14. The method of claim 13, further comprising subsequently firing
one or more of the jars again below the stuck drill string
section.
15. The method of claim 12, further comprising selectively firing,
using a digital signal from the surface command device, two or more
jars sequenced in time so that their forces meet in a constructive
manner at a preselected point in the drill string.
16. The method of claim 12, further comprising selectively firing,
using a digital signal from the surface command device, two or more
jars sequenced in time so that their forces meet in a destructive
manner at a preselected point in the drill string.
17. The method of claim 12, further comprising selecting from the
surface command device the direction two or more of the jars will
fire sequentially, up the drill string or down the drill
string.
18. The method of claim 12, wherein the selectively controlling
comprises digitally selectively controlling one or more of the jars
from the surface command device.
19. The method of claim 18, further comprising generating a model
of the drill string, including the jars, and using the model in
digitally controlling the cocking, firing, direction, and/or amount
of force used in each of the jars.
20. The method of claim 12, further comprising charging one or more
of the jars from the surface command device by actuating a
digitally-controlled valve in the jar which directs hydraulic
pressure from within the drill string to charge the jar.
21. The method of claim 12, wherein the communication components
comprise a wireless device in two or more of the jars, the method
further comprising sending a wireless electromagnetic signal from
the surface command device to two or more of the jars, or from two
or more jars to the surface command device.
22. The method of claim 12, wherein the communication components
comprise wiring in one or more of the jars, the method further
comprising sending an electromagnetic signal from the surface
command device to two or more of the jars through wired connections
in the drill string, or from two or more of the jars to the surface
command device.
23. A method of jarring comprising: communicating between a surface
command device and communication components in one or more jars of
a drill string, the drill string comprising a plurality of spaced
apart jars positioned in a corresponding plurality of wired pipe
sections; digitally selectively controlling at least one of
charging, firing, amount of force, and direction of force, of one
or more of the jars with the surface command device; firing a
sub-set or all of the jars in a digitally controlled manner and
determining depth of a stuck drill string section through analysis
of behavior or performance of the fired jars; and subsequently
digitally selectively controlling firing one or more of the jars
below the stuck drill string section via the surface command
device.
24. A method of jarring comprising: communicating between a surface
command device and communication components in two or more jars of
a drill string, the drill string comprising a plurality of spaced
apart jars positioned in a corresponding plurality of wired pipe
sections; digitally selectively controlling at least one of
charging, firing, amount of force, and direction of force, of two
or more of the jars via the surface command device; selectively
firing, using one or more digitally controlled signals from the
surface command device, two or more jars sequenced in time so that
their forces meet in one of a constructive and destructive manner
at a preselected point in the drill string.
25. A method of jarring comprising: communicating between a surface
command device and communication components in one or more jars of
a drill string, the drill string comprising a plurality of spaced
apart jars positioned in a corresponding plurality of wired pipe
sections; selectively controlling at least one of charging, firing,
amount of force, and direction of force, of one or more of the jars
using the surface command device; charging one or more of the jars
from the surface command device by actuating a digitally-controlled
valve in the jar which directs hydraulic pressure from within the
drill string to charge the jar.
26. A method of jarring comprising: electromagnetically
communicating between a surface command device and electromagnetic
communication components in one or more jars of a drill string, the
drill string comprising a plurality of spaced apart jars positioned
in a corresponding plurality of wired pipe sections; and
selectively controlling at least one of charging, firing, amount of
force, and direction of force, of two or more of the jars using the
surface command device; wherein the electromagnetically
communicating is selected from the group consisting of i) sending a
wireless electromagnetic signal from the surface command device to
two or more of the jars, or from two or more jars to the surface
command device, ii) sending an electromagnetic signal through wired
connections from the surface command device to two or more of the
jars, or from two or more of the jars to the surface command
device, and iii) combinations thereof.
Description
[0001] This application claims priority to U.S. Provisional
Application No. 61/351, 177, filed on Jun. 3, 2010, which is
incorporated herein by reference in its entirety for all
purposes.
BACKGROUND INFORMATION
[0002] 1. Technical Field
[0003] The present disclosure relates in general to methods of
operating downhole jars used during drilling, completing, or
producing products from wellbores, for example, but not limited to,
wellbores for producing hydrocarbons from subterranean formations,
and more particularly to methods of controlling the charging,
firing, amount of force, and/or direction of force exerted by one
or more downhole jars.
[0004] 2. Background Art
[0005] Drilling jars are tools used to free stuck drill pipe or
drill collars (herein referred to generically as "drilling
apparatus") by storing energy through application of axial load to
an end of the jar, then releasing that energy in rapid motion to
jar the pipe free from the point where it is stuck. "Jarring" is
the process of trying to free a stuck drill string through delivery
of impact loads to the stuck components. Drilling jars aid the
process. The jarring direction, impact intensity and jarring times
can be controlled from the rig floor. In one known apparatus, two
jars are arranged in a series, with collars or drill pipe
therebetween, on a drill string. The jars can be selectively fired
to effect a stress wave in the wellbore. By using an electronically
actuated jar, a series of jars could be set off at slightly
different times to maximize the stress wave propagation and
impulse.
[0006] So-called "downhole transmission systems" for transmitting
power and/or signals from the surface to downhole components
(including jars) and vice versa are known. Certain of these known
apparatus and methods for integrating transmission cable into the
body of selected downhole tools, such as drilling jars, can have
variable or changing lengths. Certain wireless systems used in a
different context (time-lapsed seismic data acquisition system) are
also known.
[0007] Jars are most effective at freeing stuck pipe when located
above and yet close to the point where the pipe is stuck. The
further the jars are located above the stuck point, the more the
jarring force is diminished. Furthermore, as far as is known to the
inventors herein, when a jar is below the stuck point the jar
cannot be cocked or fired. Even more problematic, however, is that
even with the recent capabilities of downhole transmission systems
to offer real time data, and even if multiple jar sets are employed
in making up a drill string, jars are rarely if ever optimally
positioned with respect to the stuck point(s), which of course
cannot be known in advance. It would be advantageous if multiple
jars could be disposed on a drillstring, and their cocking
(charging), firing, amount of force and/or direction of force
controlled from the surface in a coordinated manner, to satisfy
many drilling and well workover needs, including helping to locate
stuck points and accomplish the goal of unsticking stuck drill
string components in a logical, efficient manner. The methods of
the present disclosure are directed to these needs.
SUMMARY
[0008] In accordance with the present disclosure, it has now been
determined that one or more of charging, firing, the amount of
force exerted, and/or the direction of the forces exerted by
multiple downhole jars and/or jar accelerators can be digitally
controlled from the surface, and many advantageous operations are
available to the driller or well operator that heretofore have not
been described.
[0009] These and other needs are addressed in the art by a method
of jarring. The method of jarring can include communicating between
a surface command device and communication components in two or
more jars of a drill string, the drill string comprising a
plurality of spaced jars positioned in a corresponding plurality of
wired pipe sections; and selectively controlling at least one of
charging, firing, amount of force, and direction of force, and two
or more of these parameters, of two or more of the jars via at
least one of the surface command devices.
[0010] According to various embodiments, the present teachings can
also include a method of freeing stuck components of a drill string
in a subterranean borehole. The method can include drilling a
borehole using the drill string, the drill string comprising a
plurality of spaced apart jars and a plurality of wired drill pipe
sections, the drill pipe section and jars each comprising
electromagnetic components allowing communication at least between
the jars and a surface command device; communicating between the
surface command device and the communication components in two or
more of the jars; and selectively controlling at least one of
charging, firing, amount of force, and direction of force, of two
or more of the jars via the surface command device.
[0011] According to various embodiments, the present teachings can
further include a method of jarring. The method can include
communicating between a surface command device and communication
components in one or more jars of a drill string, the drill string
comprising a plurality of spaced apart jars positioned in a
corresponding plurality of wired pipe sections; digitally
selectively controlling at least one of charging, firing, amount of
force, and direction of force, of one or more of the jars with the
surface command device; firing a sub-set or all of the jars in a
digitally controlled manner and determining depth of a stuck drill
string section through analysis of behavior or performance of the
fired jars; and subsequently digitally selectively controlling
firing one or more of the jars below the stuck drill string section
via the surface command device.
[0012] According to various embodiments, the present teachings can
also include a method of jarring. The method can include
communicating between a surface command device and communication
components in two or more jars of a drill string, the drill string
comprising a plurality of spaced apart jars positioned in a
corresponding plurality of wired pipe sections; digitally
selectively controlling at least one of charging, firing, amount of
force, and direction of force, of two or more of the jars via the
surface command device; selectively firing, using one or more
digitally controlled signals from the surface command device, two
or more jars sequenced in time so that their forces meet in one of
a constructive and destructive manner at a preselected point in the
drill string.
[0013] According to various embodiments, the present teachings can
also include a method of jarring including communicating between a
surface command device and communication components in one or more
jars of a drill string, the drill string comprising a plurality of
spaced apart jars positioned in a corresponding plurality of wired
pipe sections; selectively controlling at least one of charging,
firing, amount of force, and direction of force, of one or more of
the jars using the surface command device; charging one or more of
the jars from the surface command device by actuating a
digitally-controlled valve in the jar which directs hydraulic
pressure from within the drill string to charge the jar.
[0014] According to various embodiments, the present teachings can
also include a method of jarring including electromagnetically
communicating between a surface command device and electromagnetic
communication components in one or more jars of a drill string, the
drill string comprising a plurality of spaced apart jars positioned
in a corresponding plurality of wired pipe sections; and
selectively controlling at least one of charging, firing, amount of
force, and direction of force, of two or more of the jars using the
surface command device; wherein the electromagnetically
communicating is selected from the group consisting of i) sending a
wireless electromagnetic signal from the surface command device to
two or more of the jars, or from two or more jars to the surface
command device, ii) sending an electromagnetic signal through wired
connections from the surface command device to two or more of the
jars, or from two or more of the jars to the surface command
device, and iii) combinations thereof.
[0015] As used herein, the term "digital" when applied to the term
"signal" means signals that have outputs of only two discrete
levels. Examples: 0 or 1, high or low, on or off, true or false.
The phrases "digital control" and "digitally controlled signals"
mean that controllers used have the advantages and disadvantages of
digital controllers. Advantages can include flexibility,
multiplicity of function, the ability to make use of advanced
design and analysis techniques (as further explained herein), and
implementation of hierarchal control schemes. The main
disadvantages in digital control are that the signals are sampled
and quantized. Also, digital control implies that a model of the
system being controlled is available, or may be generated by
observing similar processes. The model is used for extracting more
information from the process being controlled, and predicting the
result of taking certain actions and then being able to choose
values of inputs to achieve particular outputs. Digital signals may
be selected from electronic (wired and/or wireless), optical, and
acoustic (for example, mud-pulse techniques, and through-pipe
acoustic signals). Certain methods of this disclosure can include
generating a drill string model, including the jars, and using the
model to digitally control the cocking, firing, direction, and/or
amount of force used in the various jars.
[0016] These and other features of the methods of the disclosure
will become more apparent upon review of the brief description of
the drawings, the detailed description, and the claims that
follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The manner in which the objectives of this disclosure and
other desirable characteristics can be obtained is explained in the
following description and attached drawings in which:
[0018] FIGS. 1 and 2 schematically illustrate a downhole
transmission network according to the prior art;
[0019] FIGS. 3 through 5, schematically illustrate various
embodiments and features of methods in accordance with the present
disclosure;
[0020] FIGS. 6 through 15 schematically illustrate non-limiting
embodiments of a downhole force generator including a downhole
valve (FIGS. 6-7), a force multiplier with hydraulic reservoir and
gas chamber (FIGS. 7-9), an energy source (FIG. 10), a lockable
latch including a downhole valve, force generator, and energy
source (FIGS. 11-12), and a serially connected valve, force
multiplier, hydraulic reservoir, gas chamber and energy source in
assembled form (FIG. 13), and a valve actuator (FIGS. 14-15) useful
in methods and apparatus of this disclosure; and
[0021] FIG. 16 illustrates one method of the present disclosure in
flowchart form according to exemplary embodiments herein.
[0022] It is to be noted, however, that the appended drawings are
not to scale and illustrate only typical embodiments of this
disclosure, and are therefore not to be considered limiting of its
scope, for the methods and apparatus described may admit to other
equally effective embodiments.
DETAILED DESCRIPTION
[0023] In the following description, numerous details are set forth
to provide an understanding of the exemplary disclosed methods and
apparatus. However, it will be understood by those skilled in the
art that the methods and apparatus may be practiced without these
details and that numerous variations or modifications from the
described embodiments may be possible. Identical reference numerals
are used throughout the several views for like or similar
elements.
[0024] As noted above, it has now been determined, and will be
described in the exemplary embodiments herein, that multiple jars
can be connected together (either electromagnetically (via wired
pipe, or wirelessly connected), optically, or acoustically through
mud-pulse or through-pipe communication) to control cocking
(charging), firing, adjusting the amount of force, or the
directions of force (either applied to and imparted by) of the
jars. Multiple jars can be placed in the drillstring, and digital
signals can be used to select which jar is to be fired, which
direction to jar the pipe, and the amount of force to be exerted by
the jars alone or added together, either constructively or
destructively. In certain embodiments, the methods can include
redirecting hydraulic pressure inside a drill pipe to the jar
cocking mechanism using digital command, allowing jars below the
stuck point to be cocked and actuated. This same hydraulic
mechanism is used in certain embodiments to control the amount of
energy the jars will store thereby allowing the force exerted to be
digitally controlled from the surface with greater precision than
previously possible.
[0025] Digital control of multiple jars can enable firing of two or
more jars in synchronization so that jarring forces can be either
constructive or destructive when the pulses from multiple jars
meet.
[0026] Constructively summed forces can be non-exclusively used to
(1) reinforce one with another to deliver stronger impacts at the
stuck point; (2) simultaneously apply jarring loads from below and
above the stuck point; (3) time-delay the firing of multiple jars
one slightly behind the other to deliver a lengthier impulse to the
stuck point; and (4) generate buckling loads which will create
lateral forces which can dislodge materials that have bridged
around the pipe or can be used to lift the pipe away from a point
where it is differentially stuck due to wellbore fluid pressures
being much greater than formation fluid pressures.
[0027] The firing of two or more jars in a phased sequence can be
used to concentrate forces in a particular area of the drill string
or to prolong the duration of the application of the force. By
configuring the timing sequence of the firing of two or more jars,
the drill string can be used to create a buckling load which can in
turn be used to lift the drill pipe off of a differentially stuck
area or to compact drill cuttings which have packed off around the
drill pipe, creating space between the drillpipe and those cutting
to allow the operator to re-establish circulation and to restore
movement of the pipe so that the hole can be properly cleaned and
the drill string safely withdrawn or to continue to drill
further.
[0028] The extension of the duration of the firing by using
multiple jars fired in sequence can enhance the success of freeing
differentially stuck drill pipe. A single firing can begin to free
a portion of the interval stuck as the pipe is effectively peeled
off the wall of the hole where it is exposed to the differential
pressure. However, if the pipe is stuck at multiple sands down the
well or over lengthy sand, then the force decays before it can
reach those deeper intervals, while the upper portion is working
free. By firing in phases or from opposite directions, the energy
can be made available to work rapidly on the additional stuck
areas.
[0029] Additionally, the jars that are fired can be either on the
same side of the stuck point or on opposites of the stuck point
which allows forces to be applied to the stuck point from two
directions, allowing the problem to be worked from both sides at
the same time or by alternating sides, which will be more effective
than simply working the stuck point from the top as existing jars
work.
[0030] Destructively summed forces can be used to create high
tension in the drill pipe at the point where the forces meet, which
can then be used to separate the pipe at a tool joint thereby
eliminating the need to trip wireline into the well to fire a
"string" charge to jump a drill pipe connection.
[0031] The depth of a stuck point, points or length of stuck area
can be determined by selectively firing a jar or jars at certain
depth(s) then monitoring the drill string response at the surface
or downhole via accelerometers.
[0032] Jars can also be fired in sequence to concentrate their
forces at a particular tool joint which will allow the operator to
jump that joint and separate the drill sting into two parts.
Traditionally, this has been done with explosives (string shots) to
create the force that allow the pin to "jump" a box without
damaging the box. Then the operator is able to pull the upper half
of the drill string and change components to aid in retrieving the
lower stuck sting and then trip back in the well and screw back
into the same box and continue the fishing operation. Phased firing
can be conducted where one jar above and another below are fired
such that the energy arrives at the connection where the operator
wants to jump the pin at precisely the same moment.
[0033] Certain method embodiments can include coordinated firing of
two or more independent jars in a phased firing arrangement so that
energy arrives from two directions at the same time at a particular
targeted point in the drill string. Due to the very high speed of
the shock wave in the pipe, timing precision may not always be
available on digital communication networks used along drillpipe
due to noise on the network. An untimely miscommunication due to
delays created in the bit checking protocols of the network could
create an improper sequence of firings. In accordance with certain
exemplary method embodiments, the methods described herein can
include synchronizing the firing clocks in the individual jars. The
individual clocks can continually synchronize themselves to a
network clock and then be instructed to fire themselves at some
predetermined time (in some embodiments determined by a signal from
the surface, in other embodiments, pre-loaded while making up the
drill string) to assure that all bit checking protocols are assured
to have been completed before any of the jars are actually fired.
In certain embodiments, two or more jars can communicate between
each other on the network to ensure that they have all received and
understood the same firing time with a checking scheme directly
between them.
[0034] Methods of the present disclosure are applicable to both
on-shore (land-based) and offshore (subsea-based) drilling.
[0035] In order to better understand the methods of the present
disclosure; a discussion of one useable downhole network (or
downhole transmission system) is presented in relation to FIGS. 1
and 2. It will be understood that this is but one embodiment of a
suitable downhole transmission system useable to carry out the
methods of the present disclosure. Referring to FIG. 1, a drill rig
10 may include a derrick 12 and a drill string 14 including
multiple sections of drill pipe 16 and other downhole tools. Drill
string 14 is typically rotated by drill rig 10 to turn a drill bit
20 that is loaded against the earth 19 to form a borehole 11.
Rotation of drill bit 20 may alternately be provided by other
downhole tools such as drill motors, or drill turbines (not
illustrated) located adjacent to drill bit 20.
[0036] A bottom-hole assembly may include drill bit 20, sensors,
and other downhole tools such as logging-while-drilling ("LWD")
tools, measurement-while-drilling ("MWD") tools,
diagnostic-while-drilling ("DWD") tools, or the like. Other
downhole tools may include heavyweight drill pipe, drill collar,
stabilizers, hole openers, sub-assemblies, under-reamers, rotary
steerable systems, drilling jars, drilling shock absorbers, and the
like, which are all well known in the drilling industry. Note that
in prior art systems as illustrated, it is not known to utilize
multiple jar sets spaced apart in the drill string, as heretofore
it would have been a large expense to do so without any return on
investment.
[0037] While drilling, a drilling fluid is typically supplied under
pressure at drill rig 10 through drill string 14. The drilling
fluid typically flows downhole through a central bore of drill
string 14 and then returns uphole to drill rig 10 through an
annulus 9 formed between borehole 11 and drill string 14.
Pressurized drilling fluid is circulated around drill bit 20 to
provide a flushing action to carry the drilled earth cuttings to
the surface.
[0038] FIG. 2 illustrates further features of a prior art downhole
transmission system. A downhole network 17 may be used to transmit
information along drill string 14. Downhole network 17 may include
multiple nodes 18a-e spaced at desired intervals along drill string
14. Nodes 18a-e may be intelligent computing devices, such as
routers, or may be less intelligent connection devices, such as
hubs, switches, repeaters, or the like, located along the length of
network 17. Each of nodes 18 may or may not have a network address.
Node 18e may be located at or near the bottom hole assembly. The
bottom hole assembly may include drill bit 20, drill collar, and
other downhole tools and sensors designed to gather data, perform
various functions, or the like.
[0039] Other intermediate nodes 18b-d may be located or spaced
along network 17 to act as relay points for signals traveling along
network 17 and to interface to various tools or sensors (but not
jars) located along the length of drill string 14. Likewise, a
top-hole node 18a may be positioned at the top or proximate the top
of drill string 14 to interface with an analysis device 26, such as
a personal computer 28.
[0040] Communication links 24a-d may be used to connect the nodes
18a-e to one another. Communication links 24a-d may include cables
or other transmission media integrated directly into the tools
configuring the drill string 14, routed through the central bore of
drill string 14, or routed externally to drill string 14. Likewise,
in certain embodiments, communication links 24a-d may be wireless
connections. In selected embodiments, downhole network 17 may
function as a packet-switched or circuit-switched network 17.
[0041] To transmit data along drill string 14, packets 22a, 22b may
be transmitted between nodes 18a-e. Packets 22b may carry data
gathered by downhole tools (but not heretofore jars) or sensors to
uphole nodes 18a, or may carry protocols or data necessary to the
function of network 17. Likewise, some packets 22a may be
transmitted from uphole nodes 18a to downhole nodes 18b-e. For
example, these packets 22a may be used to carry control signals or
programming data from a top-hole node 18a to tools or sensors
interfaced to various downhole nodes 18b-e. Thus, downhole network
17 may provide a high-speed path for transmitting data and
information between downhole components and devices located at or
near the earth's surface 19, but as yet has not been used as taught
herein for methods of jarring including electromagnetically
communicating between at least one surface command device and
electromagnetic communication components in one or more jars of a
drill string comprising a plurality of spaced apart jars positioned
in a corresponding plurality of wired pipe sections; and
selectively controlling at least one of charging, firing, amount of
force, and direction of force, and two or more of these parameters,
of one or more of the jars using at least one of the surface
command devices.
[0042] As used herein the phrase "surface command device" means an
apparatus such as a personal computer, server computer, hand-held
computer, laptop computer, and the like, which may have data
manipulation, data storage, and data acquisition software, as well
as computation algorithms and software models accessible and usable
by humans, or by another device accessible by humans, and is does
not include surface devices such as pipes, BOPs, pumps, top drives,
compressors, rigs, tanks, and other surface or downhole tools.
[0043] Referring now to FIGS. 3, 4 and 5, non-limiting exemplary
embodiments of the present disclosure are illustrated. It should be
readily apparent to one of ordinary skill in the art that the
schematics depicted in FIGS. 3, 4 and 5 represent generalized
illustrations and that other components can be added or existing
components can be removed or modified. To avoid undue repetition,
the embodiments illustrated in FIGS. 3, 4 and 5 can include more
than one feature of the methods of the present disclosure, but it
will be understood that only one feature need be used to be within
the methods of this disclosure.
[0044] Referring first to FIG. 3, embodiment 100 includes a drill
string 14 as previously described drilling toward a
hydrocarbon-bearing subterranean formation 190, with addition of
multiple jars 102a, 102b, and 102c electromagnetically connected
through a wired network represented by arrowed lines 108 to a
surface device 28, such as a personal computer or server computer.
Jars 102a, 102b, and 102c interact with nodes 18b, 18c, and 18d,
respectively, in drill string 14. More than three jars 102 can be
present, in certain embodiments many more than three. In certain
embodiments, one jar 102 can be positioned between adjacent drill
string pipe segments 16, but this is not necessary in every
embodiment.
[0045] As illustrated schematically in FIG. 3, dashed curved lines
representing impact force 106b emanating downward from jar 102b and
impact force 106c emanating upward from jar 102c, respectively, can
meet constructively (in certain embodiments destructively) at a
"stuck point" 104, where drill string 14 is differentially stuck in
the wellbore. Stuck point 104 can actually extend several meters
axially along drill string 14. In all exemplary embodiments herein,
it will be appreciated that the term "point" is not necessarily
limiting to a tangential type point, but can include a surface area
or region over which a drill pipe is stuck, typically against an
inner surface of the wellbore 11. Assuming the location of stuck
point 104 was already known, and if the constructive force is great
enough, drill string 14 will be freed. In certain embodiments,
drill string can be rotated or twisted during application of the
jar impact forces, and/or lifted up or pushed down further into
wellbore 11. The charging and firing of jars 102 is
digitally-controlled by the operator inputting commands into
computer 28.
[0046] In certain embodiments, two or more jars may be fired in
quick succession. This is illustrated in FIG. 3, wherein jar 102a,
creating downward force 106a, can be fired first, then jar 102b,
creating downward force 106b is fired next. This technique can be
carried on through all jars between jar 102a and stuck point 104,
with the firing time of each successive jar time-delayed compared
to the previous jar, so that a relatively constant jarring impact
force is carried through along the drill string to the stuck point
104. This can be helpful in situations where the exact location of
the stuck point, or its length, is uncertain, because the impact
force decreases with distance away from the impact.
[0047] The location of the stuck point can be determined by
monitoring the reaction of one or more accelerometers 110a, 110b,
and 110c, as illustrated in embodiment 200 of FIG. 4. FIG. 4
schematically illustrates an exemplary method embodiment 200
employing a wired network 108, and FIG. 5 schematically illustrates
an exemplary method 300 employing a wireless network, indicated by
dashed lines 112. Accelerometers 110a, 110b, and 110c are
illustrated in FIG. 4 as electromagnetically connected via
hard-wire connections to surface device 28 through nodes 18, as
indicated by double-headed solid arrows 108. In FIG. 5,
accelerometers 110a, 110b, and 110c are illustrated as
electromagnetically connected via wireless signals between wireless
components in nodes 18 to surface device 28, as indicated by
double-headed dashed arrows 112. Electromagnetic wired connections
also exist between valves 114a, 114b, and 114c and surface device
28 in embodiment 200, via nodes 18, and in embodiment 300 via
wireless electromagnetic signals. Valves 114 allow pressurized
fluid in drill pipe 16, such as drilling fluids, to charge (cock or
set, or adjust a setting) of a jar 102, and in certain embodiments
can fire one or more jars 102.
[0048] Embodiment 300 of FIG. 5 also illustrates that in certain
embodiments of this disclosure, one or more, or all of jars 102 can
include a jar accelerator 116. As described previously herein, jar
accelerators can be useful in shallow well depths, where the
shallow depth can limit the available pipe stretch or compression
to obtain strong jarring impacts. Friction in high angle and
horizontal wells can impede drill string rebound when the jars are
tripped, thus damping the jarring impacts. In such embodiments, a
"jar accelerator" (sometimes referred to as "jar intensifier" and
"jar enhancer" in the art) is placed above the jar. Embodiments
wherein the accelerator is placed adjacent the jar, as illustrated
in FIG. 5 at 116, or with a few drill collars between the jar and
accelerator are intended to be included within the scope of the
exemplary embodiments herein. The telescoping accelerator can serve
as an elastic spring to store energy until the jar is triggered.
When the jar is triggered, the accelerator quickly releases its
stored energy and accelerates the hammer of the drilling jar to a
relatively high speed. The impact force is related to the square of
the velocity, thus, the accelerator greatly increases the hammer
force. The spring medium can be steel (mechanical accelerator),
compressible oil (hydraulic accelerator) or nitrogen (gas
accelerator). Useful jar accelerators for practicing the methods of
this disclosure can be single- or double-acting jar
accelerators.
[0049] FIGS. 6-15 schematically illustrate exemplary non-limiting
embodiments of a downhole force generator including a downhole
valve (FIGS. 6-7), a force multiplier with hydraulic reservoir and
gas chamber (FIGS. 7-9), an energy source (FIG. 10), a lockable
latch including a downhole valve, force generator, and energy
source (FIGS. 11-12), and a serially connected valve, force
multiplier, hydraulic reservoir, gas chamber and energy source in
assembled form (FIG. 13), and a valve actuator (FIGS. 14-15) useful
in methods and apparatus of this disclosure. It should be readily
apparent to one of ordinary skill in the art that the schematics
depicted in FIGS. 6-15 represent generalized illustrations and that
other components can be added or existing components can be removed
or modified.
[0050] Referring to FIGS. 6A and 6B, the downhole force generator
of embodiment 500 can include an outer cylindrical sleeve 502,
typically a drill pipe or drill collar, and a series of inner
cylindrical sleeves 504, 506, and 508, as well as a valve 514. A
force multiplier can also be included, as illustrated schematically
in FIG. 7, and which will be described after describing FIGS. 6A
and 6B. FIG. 6A schematically illustrates valve 514 in a
flow-through position, where drilling fluid 512 may flow through
ball valve 514 via a passage formed by a first ball port 528, and
an inner passage 509 formed through hollow piston rods 522a, 522b,
and 522c, and through piston heads 524a, 524b, and 524c. FIG. 6B
illustrates valve 514 in a force-generate position, after a ball
member 516 has rotated clockwise about a valve pivot 526. Valve 514
is depicted in this embodiment as a rotatable ball valve, having
ball member 516 rotatably positioned in a valve block 518. Ball
valve member 516 is actuated upon command (via surface-to-downhole
telemetry) by a downhole motor (not illustrated in FIGS. 6A and 6B,
see FIG. 13 and description) powered by a downhole power source
(which may be one or more batteries, or power cables).
[0051] The flow-through position of valve 514 illustrated in FIG.
6A is used during most drilling operations. The force-generate
position illustrated in FIG. 6B is created by rotating ball member
516 clockwise 90.degree. from the flow-through position whereupon
pressurized drilling fluid is diverted through a second ball valve
port 530, through outer passages 510 in sleeves 504, 506, and 508,
and then to the force multiplier (FIG. 7). It will be understood
that ball member 516 can be made to rotate counter-clockwise, with
suitable design changes, to effect the change from the flow-through
position to the force-generate position. Upon drilling fluid being
forced to flow into outer passages 510, it then traverses into
spaces on the under-sides of pistons 524, this in turn causing
piston heads 524 to move in cavities 521 (in the illustration of
FIG. 6B, to the right). Cavities 521 are defined by internal
surfaces 520 of inner cylindrical sleeves 504, 506, and 508 of
force generator 500 and by outer surfaces of respective hollow
piston rods 522.
[0052] Embodiment 600 of FIG. 7 illustrates the valve and force
generator of embodiment 500 in the force-generate position of FIG.
6B, and also illustrates schematically a force multiplier connected
in series therewith. The force multiplier can include, in this
non-limiting embodiment, a selectable number of power sections
threadably attached (threads not shown) in series, each power
section including a hollow piston rod 522c, 522d, and 522e, as well
as piston heads 524c, 524d. Each piston head 522 can be threadably
connected to its respective hollow piston rod, or welded thereto.
Piston head 524c slides within inner cylindrical sleeve 532 and
piston head 524d slides within inner cylindrical sleeve 534.
Another inner cylindrical sleeve 536 completes the embodiment. Each
power section (piston rod, piston head, inner cylindrical sleeve
combination) of the force multiplier provides a certain piston area
upon which fluid pressure is applied thereby generating axial force
transmitted along the center shaft. For example, if the piston area
is ca. 7.1 in.sup.2 (i.e., via a 41/4''.times.3'' piston) and 5,000
psi pressure is applied from surface through the drillstring, then
each piston develops 35.5 klb.sub.f (disregarding friction and
other offsetting forces) and 4 power sections (as depicted in FIG.
7) can produce in total 142 klb.sub.f. The amount of force
generated is selectively controlled by the applied pressure and
number of power sections, within reasonable operating limits of all
components.
[0053] FIGS. 8 and 8A illustrate the force multiplier of embodiment
600 in greater detail. In this detail of embodiment 600, inner
cylindrical sleeve 536 encompasses outer and inner hydraulic fluid
cylinders 546 and 547, respectively. A passage 542 allows flow of
hydraulic fluid 544 into a hydraulic fluid reservoir 548 defined
between hydraulic fluid cylinders 546, 547. A floating piston 550
separates hydraulic fluid reservoir 548 from an inert gas chamber
558 formed between cylinders 546, 547, floating piston 550, and a
closed distal end 552 of cylinders 546, 547. Another inner
cylindrical sleeve 538 abuts against distal end 552. Appropriate
seals 540 are provided, which maintain clean hydraulic fluid from
being contaminated by drilling fluid. Hydraulic fluid is displaced
by the force generator pistons 524b, 524c, and 524d into hydraulic
reservoir 548 appropriately sized to receive the total fluid volume
displaced from the total number of force multiplier power sections.
Moderate hydraulic fluid pressure is applied against a floating
piston 550 over an inert gas charge in gas chamber 558. The gas
charge provides a highly compressible volume to limit the rise of
hydraulic fluid pressure acting against drilling fluid pressure
applied to force generator pistons 524. The gas charge also stores
sufficient energy to aid return of force generator pistons 524 to
their starting positions. Clean hydraulic fluid serves to lubricate
and keep clean the piston bores. Seals 540 are used to achieve
required pressure differentials and minimize contamination between
drilling and hydraulic fluids. An effective hydraulic seal formed
by the outer case 502 around all inner cylindrical sleeves 504,
506, 508, 532, 534, 536, 538, 539, and 541 (the latter two are
illustrated in FIG. 11B) is assumed, which in practice can be
achieved through appropriately selected and located seal elements
(not illustrated). Hydraulic fluid reservoir 548 includes an
open-end cap 554, defining an entry/exit passage 556 through which
hydraulic fluid is allowed to pass in this embodiment.
[0054] FIGS. 6-8 are schematic illustrations and not meant to
suggest relative dimensions. FIGS. 9A and 9B depict an embodiment
having rough probable relative dimensions for the various
components of force multipliers useful in the methods and apparatus
of this disclosure. The 81/4 inch OD.times.51/4 inch ID of the
outer cylindrical sleeve 502 is consistent with a 65/8 inch nominal
diameter drill pipe tool joint dimensions. Because the assembled
apparatus presented herein are typically located in the
drillstring, it is important they do not introducing structural
weakness into the drill string. The 23/4 inch flow-through bore 509
is consistent with an 8 inch OD.times.23/4 inch ID 150 lb/ft drill
collar dimensions, as it is also important that the assembled
apparatus not introduce undue hydraulic or drift ID restrictions in
the drillstring.
[0055] FIGS. 10A and 10B schematically illustrate an energy source,
in this embodiment a coiled steel spring 560 that has been
compressed into a loaded position by the combined action of
drilling fluid acting on piston head 524d, which in turn exerts
axial force onto hollow piston rod 522e and piston head 524e,
compressing spring 560. Piston head 524d also forces hydraulic
fluid 544 into reservoir 548. Hydraulic fluid 548 lubricates hollow
piston rod 522e as it travels through inner cylinder 547 and
through inner cylindrical sleeve 538. Spring 560 can store and
releases force created by the force multiplier, described above. In
this exemplary embodiment, coiled steel spring 560 is compressed to
store energy then controllably released to decompress on demand.
Spring 560 is, in this embodiment, centered about hollow piston rod
522f. Upon digitally-controlled decompression of spring 560, piston
head 524f exerts a jarring axial force on inner sleeve 539, and
piston head 524e exerts a jarring axial force on inner sleeve 538,
as illustrated in FIG. 10B, which illustrates the unloaded position
of spring 560.
[0056] Referring now to FIGS. 11A, 11B, and 11C, a hydraulic latch
is schematically illustrated. A latch is defined in this embodiment
as a combination of valve 514, a force generator mechanism, the
latter defined by a selected number of inner cylindrical sleeves
504, 506, and 538 and hollow piston rods 522a, 522e, and 522f, and
piston heads 524a, 524e, and coil spring 560 in the illustrated
embodiment of FIGS. 11A and 11B. The latch operates to hold and
release coiled spring 560. Latching (or locking) of coil spring 560
is achieved by rotating ball member 516 by 1/8 turn clockwise from
the force-generate position, as illustrated in FIG. 11C. A hollow
piston rod 522g is guided by inner cylindrical sleeve 541 in this
embodiment.
[0057] FIG. 12A is essentially the same as FIG. 11C, and
illustrates the position of ball member 516 when coil spring 560 is
locked into position. FIG. 12B illustrates how the hydraulic latch
is released by further rotating ball member 516 by 1/8 turn
clockwise from the locked position, whereupon resistance against
the coiled spring 560 is relaxed via release of drilling fluid
pressure from the force multiplier. The sliding piston/piston rod
assembly 524e/522e rebounds to its starting position whereupon a
portion of the stored axial load is transferred from the
piston/piston rod 524e/522e to the inner sleeve 538 opposite the
direction from which it was created. Ball member 516 is returned to
the flow-through position (FIG. 6A) by rotating about
180.degree..
[0058] FIG. 13 illustrates the valve/latch, force multiplier,
hydraulic reservoir and energy source in composite. The components
are serially assembled to form one embodiment of a working jar
device useful in apparatus and methods of the present disclosure.
Coil spring 560 is illustrated in a cocked or loaded position, and
can be locked into that position using the ball member 516, as
described in reference to FIG. 12.
[0059] FIGS. 14A and 14B are schematic axial cross-sectional views
of the valve 514 of FIG. 6, illustrating probable relative
dimensions of the components. In one view (FIG. 14B) a
representation of a DC motor 562 and linear actuator 564
combination are superimposed upon and in approximate relation to
the valve cross-section. The DC motor 562 and linear actuator 564
can in certain embodiments be from about 12 to about 18 inches (30
to about 45 centimeters) in length, and can be housed in a separate
assembly immediately upstream of the valve. Motor 562 can be
battery powered in certain embodiments, or can be served by a power
cable in certain other embodiments. DC motor 562 actuates an
axially extendable rod 564 suitably geared to the ball pivot 526 to
bidirectionally rotate ball member 516 on digital command in
angular increments, thereby effecting the required flow-through,
force-generate, locked and released positions, as described
herein.
[0060] FIGS. 15A and 15B are schematic side elevation and front end
views, respectively, of a prior art DC motor linear actuator useful
in methods and apparatus of the present disclosure. In this
embodiment, a DC motor 562 is illustrated connected to a gear box
563, which in turn connects to a housing 566 which houses and
guides linear actuator 564. Clevis pins 568 and 570 can be used in
certain embodiments to connect the linear actuator to other
components in apparatus described herein, such as to an inner
cylindrical sleeve. While the DC motor 562 can run on local battery
power, an electric power cable 572 can also be provide in certain
embodiments, supplying power from the surface, or from another
downhole power source, such as another downhole tool receiving
power from the surface.
[0061] In accordance with the present exemplary embodiments, a
primary interest lies in digitally controlling, from the surface,
the charging, firing, and/or setting the amount of impact force
and/or direction of those forces of a plurality of jars positioned
along a drill string, in order to more efficiently and effectively
free stuck drill strings. The skilled drilling operator or designer
will determine which method and apparatus is best suited for a
particular well situation and formation to achieve the highest
efficiency without undue experimentation.
[0062] In actual operation, the status and/or operation of the jars
(and jar accelerators, if present) can be presented in paper
format, or more likely today, in electronic format on surface
command device 28, or a device communicating with surface command
device 28. The change in one or more of the charging, firing,
amount of impact force, and direction of impact force of each jar,
as well as other parameters, such as mud parameters, drilling
parameters, formation parameters, and the like and properties can
be tracked, trended, and changed by a human operator (open-loop
system) or by an automated system of sensors, controllers,
analyzers, pumps, mixers, agitators (closed-loop system).
[0063] Any of the jars and jar accelerators currently in use in the
drilling industry can be used in practicing the methods of this
disclosure, including bumper jars, mechanical jars, hydraulic jars,
mechanical-hydraulic jars, electro-mechanical jars, and so on. The
only requirement is that the jars be able to, or can be modified to
be able to interface electromagnetically with nodes in wired,
wireless, or a combination of wired and wireless downhole
transmission networks as described herein. The jar is basically a
telescopic slip joint including a hammer, anvil and internal
trigger that resists movement until the desired tension or
compression has been applied. Potential energy stored in the drill
string is suddenly released when the jar fires. The slip joint then
accelerates rapidly until it shoulders, delivering an impact blow.
A related device called a jar accelerator can be used in
combination with a drilling jar to intensify the jarring
impact.
[0064] To jar upward, the drill pipe is stretched via an axial
tensile load applied at the surface. This tensile force is resisted
by the jar trigger mechanism long enough to allow the pipe to
stretch and store potential energy. When the jar trips, this stored
energy is converted to kinetic energy causing the hammer and anvil
to come together rapidly. To jar downward, the pipe weight is
slacked off at the surface and, if necessary, additional
compressive force is applied to put the pipe in compression. This
compressive force is resisted by the jar trigger mechanism to allow
the pipe to compress and store potential energy. When the jar
trips, the potential energy of the pipe weight and compression is
converted to kinetic energy, causing the impact surfaces to come
together rapidly. Upon impact, some of the jarring kinetic energy
is transmitted to the stuck point. If the resultant force at the
stuck point is great enough, the stuck drill string will slide
during the impulse period and eventually be freed after a
sufficient number of jarring cycles. "Impact" is the initial
instantaneous force generated by the jar. "Impulse" is a residual
force of the impact, including of reverberations occurring in
milliseconds following impact. The objective of a jar is to create
a sufficiently strong impact and sufficiently strong and long
impulse.
[0065] There are many types of drilling jars, and all may be useful
in carrying out methods of this disclosure. The types include, but
are not limited to, bumper, mechanical, hydraulic,
mechanical-hydraulic, electro-mechanical, and so on. The bumper jar
is used primarily to provide a downward jarring force. The bumper
jar ordinarily contains a splined joint with sufficient axial
travel to allow the pipe to be lifted and dropped, causing the
impact surfaces inside the bumper jar to come together to deliver a
downward jarring force to the string. Mechanical, hydraulic,
mechanical-hydraulic, and electro-mechanic jars differ from the
bumper jar in that they contain some type of tripping mechanism
which retards the motion of the impact surfaces relative to each
other until an axial strain, either tensile or compressive, has
been applied to the drill string. Mechanical jars have a mechanical
latch mechanism with a preset release force. The release force
cannot be adjusted downhole, except for one particular type of
mechanical jar whose release force can be adjusted by torque. The
jar fires (moves from latched position into the free stroke) as
soon as the applied load exceeds the jar release force. Hydraulic
drilling jars provide a wide variety of possible triggering loads,
determined by the actual tensile or compressive load at the jar.
This can be accomplished by a hydraulic mechanism and so-called
metering stroke in which oil is forced to flow through a small
orifice. At the end of the metering stroke, oil bypasses the
orifice causing the hydraulic resistance to drop to a very low
value (free stroke). The metering stroke creates a delay time,
allowing the jarring operator to set the desired release force.
This selective, wide operating range of jar release force is the
major advantage of hydraulic jars. Disadvantages can include
unintended jar firing during normal drilling operations, long
metering times for low overpull, overheating the oil during
repeated jarring and risk of overloading the jar during the
metering stroke.
[0066] Many hydraulic drilling jars have a disadvantageously long
metering stroke. The metering stroke is the amount of relative
movement between the mandrel and the housing that must occur for
the jar to trigger after it is cocked by application of an axial
load. When an ordinary hydraulic drilling jar is cocked by
application of axial load, fluid is pressurized in a chamber to
resist relative movement of the mandrel and the housing. One or
more metering orifices in the jar allow the compressed fluid to
bleed off at a relatively slow rate. As the fluid is bleeding off,
there is some relative axial movement between the mandrel and the
housing. The amount of relative axial movement between the mandrel
and the housing that occurs after the jar is cocked, but before the
jar triggers, is known as bleed off. The bleed off represents lost
potential energy that might otherwise be converted to additional
jarring force. Many hydraulic drilling jar designs have a
relatively long metering stroke of 12 inches of more and,
therefore, a significant amount of bleed off. A long metering
stroke leads to heat buildup in the hydraulic fluid, which may
require costly intervals between firings and lead to degradation of
fluid. Electro-mechanical jars utilize a magnetorestrictive
material that responds to a predetermined pressure to open one or
more orifices in a shoulder of a mandrel to allow rapid pressure
communication between the upper and lower chambers.
[0067] Mechanical-hydraulic (aka hydro mechanical) jars are hybrid
jars that combine initial mechanical release (to avoid uncontrolled
firing) with hydraulic action to provide flexibility and adjustable
release force.
[0068] In certain embodiments more jarring force than is obtainable
from jars alone is desired. Shallow depths can limit the available
pipe stretch or compression to obtain strong jarring impacts.
Friction in high angle and horizontal wells can impede drill string
rebound when the jars are tripped, thus damping the jarring
impacts. In such cases a "jar accelerator" (sometimes referred to
herein as "jar intensifier") is placed above the jar, normally with
a few drill collars between the jar and accelerator. The
telescoping accelerator serves as an elastic `spring` to store
energy until the jar is triggered. When the jar is triggered, the
accelerator quickly releases its stored energy and accelerates the
hammer of the drilling jar to a relatively high speed. The impact
force is related to the square of the velocity, thus, the
accelerator greatly increases the hammer force. The spring medium
can be steel (mechanical accelerator), compressible oil (hydraulic
accelerator) or nitrogen (gas accelerator). Jar accelerators can be
single- or double-acting.
[0069] Those of ordinary skill in the hydrocarbon exploration and
drilling arts will already be familiar with some aspects of wired
and wireless downhole networks.
[0070] Wireless systems used in a different context (time-lapsed
seismic data acquisition system) are known. Electromagnetic
transmission of signals to and from surface command devices and
jars, and other optional components such as sensors, may be
"completely wireless", wherein all wires, cables, and fibers (such
as optical fibers) for communication are substantially eliminated.
This does not rule out the use of wires, cables, or optical fibers
for example in recording station equipment and jars, for example
for power. Wireless systems and methods can offer improvements over
systems and methods that use wire or optical fiber for
communications in terms of one or more of robustness, scalability,
cost, and power-efficiency. Electromagnetic signals can be used to
transfer data to and/or from the jars, to transmit power, and/or to
receive instructions to charge and/or fire jars.
[0071] Systems and methods described in the present disclosure can
employ a wireless data network comprising one or more surface
command units transmitting commands to one or more surface nodes
18a via first wireless links, which in turn transmit commands to
downhole nodes and then jars 102 via second wireless links.
Commands can be sent from node to node via wireless links, and, to
the extent data is exchanged between nodes and surface command
units, wireless links may also be considered part of the wireless
data network.
[0072] The first wireless links can be characterized as Wireless
Personal-Area Networks (WPAN). A "WPAN" is a personal area network
(PAN) using wireless connections. WPAN is currently used for
communication among devices such as telephones, computers and their
accessories, as well as personal digital assistants, within a short
range. The second and third wireless links between nodes can be
individually selected from any wireless communication protocol that
supports point to multi-point (PMP) broadband wireless access.
[0073] As used in the context of the present disclosure
(coordinated charging and firing of downhole jars), the nodes and
surface command devices can be compared to a metropolitan area
networking (MAN), as given in the 802.16 standard, sometimes
referred to as fixed wireless. In fixed wireless, a backbone of
base stations is connected to a public network. As with a MAN, each
node 18 supports many "fixed subscriber stations" (jars, sensors,
and the like), which are akin to either public WiFi hot spots or
fire walled enterprise networks. Nodes 18 can use a media access
control (MAC) layer, and allocate uplink and downlink bandwidth to
"subscribers" (jars, sensors, etc.) as per their individual needs.
This is basically on a real-time need basis. The MAC layer is a
common interface that makes networks interoperable.
[0074] Systems and methods of this disclosure can include provision
of multi-antenna signal processing (MAS) software architectures for
implementation of the second and/or third wireless links employing
WiMAX. The WiMAX profiles support both adaptive antenna system
(AAS) and multiple-input/multiple-output (MIMO) architectures in
baseline form.
[0075] "Drilling" as used herein can include, but is not limited
to, rotational drilling, directional drilling, non-directional
(straight or linear) drilling, deviated drilling, geosteering,
horizontal drilling, and the like. Rotational drilling can involve
rotation of the entire drill string, or local rotation downhole
using a drilling mud motor, where by pumping mud through the mud
motor, the bit turns while the drillstring does not rotate or turns
at a reduced rate, allowing the bit to drill in the direction it
points. A turbodrill may be one tool used in the latter scenario. A
turbodrill is a downhole assembly of bit and motor in which the bit
alone is rotated by means of fluid turbine which is activated by
the drilling mud. The mud turbine is usually placed just above the
bit.
[0076] FIG. 16 illustrates an exemplary method 400 of the present
disclosure in flowchart form. It should be readily apparent to one
of ordinary skill in the art that the method depicted in FIG. 16
represent generalized illustration and that other steps can be
added or existing steps can be removed or modified.
[0077] First, as indicated in box 402, the drilling supervisor,
probably in conjunction with a mud engineer, geologist or other
person in charge can choose downhole network components, jars, and
optionally jar accelerators; and assemble the drill string, either
on-site or at a site removed from the well.
[0078] In box 404, drilling is then begun, drilling toward a target
formation at a known azimuth and dip angle using the selected
drilling mud, drill bit, and assembled drill string.
[0079] At box 406, upon sticking of the drill string at one or more
unknown locations in the wellbore, locate sticking point using one
or more digitally-controlled jars using one or more surface command
devices. The step also includes charging selected jars and
selecting force magnitude and direction using one or more surface
command devices, and firing the jars.
[0080] At box 408, upon locating the sticking point, charge
selected jars and select force magnitude and direction using one or
more surface command devices.
[0081] At box 410, fire the charged jars using one or more surface
command devices, selecting constructive or destructive addition of
the forces.
[0082] At box 412, analyze results using one or more surface
command devices. If drill string is unstuck, continue drilling. If
drill string is not unstuck, repeat steps 408-412 until drill
string is unstuck.
[0083] From the foregoing detailed description of specific
embodiments, it should be apparent that patentable methods and
apparatus have been described. Although specific embodiments of the
disclosure have been described herein in some detail, this has been
done solely for the purposes of describing various features and
aspects of the methods and apparatus, and is not intended to be
limiting with respect to the scope of the methods and apparatus. It
is contemplated that various substitutions, alterations, and/or
modifications, including but not limited to those implementation
variations which may have been suggested herein, may be made to the
described embodiments without departing from the scope of the
appended claims. For example, drilling jars, jar accelerators, and
downhole transmission systems other than those specifically
described above can be employed, and are considered within the
scope of the disclosure.
* * * * *