U.S. patent application number 14/231607 was filed with the patent office on 2015-01-08 for open hole casing run perforating tool.
The applicant listed for this patent is John T. Hardesty, Charles E. Lancaster, Michael D. Wroblicky. Invention is credited to John T. Hardesty, Charles E. Lancaster, Michael D. Wroblicky.
Application Number | 20150007994 14/231607 |
Document ID | / |
Family ID | 52132030 |
Filed Date | 2015-01-08 |
United States Patent
Application |
20150007994 |
Kind Code |
A1 |
Lancaster; Charles E. ; et
al. |
January 8, 2015 |
Open Hole Casing Run Perforating Tool
Abstract
Disclosed is an open-hole casing perforation tool having
projecting fins around the circumference of a mandrel that have
firing mechanisms and shape charges to allow flexible operation of
geological formation fracturing at desired predetermined locations
in an oil or gas well bore.
Inventors: |
Lancaster; Charles E.;
(Willis, TX) ; Wroblicky; Michael D.; (Milsap,
TX) ; Hardesty; John T.; (Milsap, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lancaster; Charles E.
Wroblicky; Michael D.
Hardesty; John T. |
Willis
Milsap
Milsap |
TX
TX
TX |
US
US
US |
|
|
Family ID: |
52132030 |
Appl. No.: |
14/231607 |
Filed: |
March 31, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61843003 |
Jul 4, 2013 |
|
|
|
Current U.S.
Class: |
166/297 ;
89/1.15 |
Current CPC
Class: |
E21B 43/1185 20130101;
E21B 43/263 20130101 |
Class at
Publication: |
166/297 ;
89/1.15 |
International
Class: |
E21B 43/1185 20060101
E21B043/1185; E21B 29/02 20060101 E21B029/02 |
Claims
1. A tool for perforating or shock loading a geological formation
comprising: a mandrel, a series of projections, fins, located
around the outer circumference of the mandrel, wherein at least one
of the fins houses a firing head assembly.
2. The tool of claim 1 wherein the ends of the mandrel are threaded
to connect to a threaded end of casing or enlarged to be fitted
over the end of casing and secured by locking rings or pins.
3. The tool of claim 1 wherein the fins are oriented
longitudinally, laterally, and helically in reference to the
orientation of the casing string.
4. The tool of claim 1 wherein the fins are disposed on a skeletal
frame that is constructed to slide over a casing and is held in
place with locking rings.
5. The tool of claim 1 wherein shape charges are disposed in the
fins and wherein one or more directed inward toward the well.
6. The tool of claim 5 also comprising a detonation cord that is
connected to ignition port(s) of shape charges located in a manner
to explode in a predetermined direction.
7. The tool of claim 5 wherein the shaped charges are selected from
the group consisting of; deep penetrating charges, big hole charges
designed for optimal hole size, punch charges designed for limited
penetration, charges that incorporate reactive liner technology and
linear shaped charges that produce slot shaped holes.
8. The tool of claim 1 wherein the firing head assembly comprises a
pressure activated release mechanism, a firing pin, an initiator
percussion unit that ignites a detonation cord, housed in a
suitable body that can be attached to fins of the perforating tools
in a configuration to allow the initiation of detonation of shape
charges located in the fins.
9. The tool of claim 8 wherein the pressure activated release
mechanism is a rupture disc or a shear pin retained firing
system.
10. The tool of claim 8 wherein the pressure activated release
mechanism for each fin has a release mechanism set at a
predetermined release setting that may be the same or different for
individual fins.
11. The tool of claim 8 wherein the pressure activated release
mechanism is comprised of a reverse acting rupture disc.
12. The tool of claim 8 wherein the firing head assembly is modular
and interchangeable from one tool assembly to another and
configured to be easily removable from the tool.
13. The tool of claim 8 wherein the firing head assemblies are
configured to allow interchange of initiation means.
14. The tool of claim 8 wherein the firing head assembly also
comprises a time delay means to delay the time from activation to
release.
15. The tool of claim 14 wherein the firing head assembly time
delay means is selected from the group consisting of a time delay
fuse, a mechanical means, a hydraulic means, a delay mechanism that
is configured to interact with the fracture treatment, and a delay
mechanism configured to preferentially orient banks of charges to
fire in conjunction with the fracture treatment.
16. A firing head assembly for a tool comprising a pressure
activated release mechanism, a firing pin assembly, and an
initiator percussion unit that ignites a detonation means.
17. The firing pin assembly of claim 16 wherein the pressure
release mechanism comprises a reverse acting rupture disc.
18. The firing head assembly of claim 16 also comprising a shear
pin located between the release mechanism and the percussion
unit.
19. A method of perforating or shock loading a geological formation
comprising; providing a tool comprising a mandrel having a series
projections, fins disposed around the outer circumference, wherein
each projection houses a firing head assembly connected to a
detonation means that is connected to an ignition port(s) of shape
charges located in the projections in an manner to explode outward
the mandrel surface, locating the tool in a desired location of a
well casing; and activating the firing head assembly so as to
initiate the shape charges.
20. The method of claim 19 wherein the firing head assembly
comprises a pressure activated release mechanism, a firing pin, an
initiator percussion unit that ignites a detonation means, attached
to fins of a tool in a configuration to allow the initiation of
detonation of shape charges located in the fins.
21. The method of claim 19 wherein the pressure activated release
mechanism is a rupture disc and the activating means is
pressure.
22. The method of claim 19 wherein the firing head assembly has at
least one firing initiator set at a lower activation level than the
remaining assemblies so that when activated the pressure produced
activated the remaining firing head assemblies;
23. The method of claim 19 wherein there is a first and secondary
firing assembly on separate fins and detonation is initiated in a
secondary firing assembly by means of a secondary mechanism.
24. The method of claim 23 wherein the detonation means is
initiated in a secondary firing assembly by means of pressure
transmission from a first firing assembly.
25. The method of claim 19 wherein a plurality of perforating tools
are arranged in one or more stages in which the tools are disposed
in a casing string sealed by packers and wherein there is a first
and second tool and wherein activation of a first tool acts to
initiate the function of the second tool.
26. The method of claim 19 wherein perforating tools are arranged
in one or more stages in which the tools in each stage are disposed
in a casing string sealed by packers and wherein activation of a
first tool in one stage acts to activate a tool in another separate
stage.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of Provisional Application
Ser. No. 61/843,003 filed Jul. 4, 2013. The contents and
disclosures of the application is incorporated herein by reference
in its entirety for all purposes.
BACKGROUND
[0002] 1. Field of Invention
[0003] This invention relates to an oil well perforating tool and
methods in which explosive shape charges are activated by well
pressure in order to fracture surrounding geological formations
adjoining the well bore casings at predetermined locations.
[0004] 2. Background
[0005] In the oil well drilling and completion industry
hydrofracturing, or "fracing", operations can be beneficial for a
number of reasons. For example, fracturing operations help to
stimulate the production of hydrocarbons from earth geological
formations. In such operations, portions of the formation are
fractured to increase fluid flow from the formation into a
borehole. Fracturing generally includes isolating (as with packers)
a portion of the borehole and pressurizing fluid therein to a
pressure sufficient to cause a fracture in the formation. Boreholes
may include both vertical and horizontal sections, such as long
horizontal wells commonly used in shale gas and other tight
formations. In recent years many methods have been used to allow
multiple fractures to be induced along the length of a lateral
section.
[0006] These wellbore fractures are initiated by applying pressure
to the annulus of the wellbore once a sliding sleeve has been
opened either hydraulically or with a ball. The only fractures that
will occur are the ones where the formation is weaker in its
natural state. These hydraulically induced fractures may not be in
an area of the formation that has been determined to be the best
locations for removing all or as much of the hydrocarbons. It
should be common practice to explosively fracture well casings at
preferred locations in the geological formations that are
considered most promising. Open hole casing shock loading or
perforating tools should be are used for such fracturing.
[0007] We disclose an improved pre-fracturing energetic tool and
methods for using it.
SUMMARY
[0008] The apparatus (tool) of this invention allows perforations
or shock loading to help allow induced fracture to be placed
wherever it is determined to have the best results. Perforations
are mechanically applied to the formation where needed compared to
just using applied pressure to initiate a natural fracture. There
is no limit to the number of tools that can be placed in a single
stage (group of individual tools). By perforating the formation
with multiple tools, the number of fractures is increased in the
wellbore. Pumping pressures are reduced because the breakdown
pressures of the formation have been reduced. Stage spacing can be
lengthened by installing more perforating tools in a stage and
reducing the number of open hole packers and reducing the risk of
packer failure. Shorter fracing times are achieved due to reduced
number of stages preformed.
DESCRIPTION OF THE FIGURES
[0009] The Figures represent embodiments of the invention and are
not intended to be limiting of the scope of the invention.
[0010] FIG. 1 is a cutaway drawing of the tool of the invention to
illustrate the internal components.
[0011] FIG. 2A is a partial end view of the tool of the invention.
There can be as many or as few blades (fins) as is desired.
[0012] FIG. 2B is a partial end view of the tool of the invention.
There can be as many or as few blades (fins) as is desired.
[0013] FIG. 3 is a transparent cutaway view illustrating the radial
positions of the components of an embodiment of the invention.
[0014] FIG. 4 is a drawing that represents a tool of the invention
as it would be run in a well hole before being threaded to a liner
string.
[0015] FIG. 5 is a schematic drawing of a tool that is an
embodiment of the invention.
[0016] FIG. 6 is an end view of the tool of FIG. 5.
[0017] FIG. 7 is a schematic drawing of a firing head component of
the tool of FIG. 5.
[0018] FIG. 8 is an illustration of a typical down-hole perforating
tool arrangement using three tools and a single frac sleeve in a
shorter stage configuration.
[0019] FIG. 9 is an illustration of a typical down-hole arrangement
using six tools and a single frac sleeve in a longer stage
configuration.
DESCRIPTION
[0020] In broad aspect the invention is a geologic formation
perforation (or energetic) tool that allows a formation to be
pre-fractured (or shock loaded) prior to high pressure liquid
hydro-fracture (fracing) and includes methods of employing the tool
in geologic formation fracturing.
[0021] The tool comprises, a mandrel having a series of
projections, fins, located around the outer circumference, at least
one of which fins houses a firing head assembly that may be
connected to a detonation means (such as detonating cord). The
detonating means are connected to ignition port(s) on shape charges
that may be located on the fins. The mandrel body may be
constructed with threaded ends for threading into a casing string.
It may also be enlarged to fit over the casing and attached to the
casing by fitting the mandrel body over casing and securing it with
locking rings or pins.
[0022] In general, most but not necessarily all, of the fins will
have a firing head assembly disposed in it. The fins are oriented
longitudinally, laterally, and/or helically in reference to the
orientation of the casing string. The fins are preferable disposed
on the mandrel body in a customary array such as shown in FIG. 1.
However, they may also be disposed on a skeletal frame that slides
over the conveyed casing and held in place with locking rings or
other suitable means.
[0023] The shaped charges, if used, are, in most applications,
located in a manner to explode outward of the mandrel surface into
the geological formation. The charges may be positioned in the
mandrel so that one or more of the shaped charges produce a jet
that constructively interact--that is produces jets that intersect
in the formation. In some applications one or more of the shaped
charges may be directed inward towards the well to create an
additional communication port between the wellbore and the
annulus.
[0024] The firing head assembly may be configured to incorporate a
time delay mechanism. The firing head assembly time delay means can
be any suitable means, including but not limited to, a time delay
fuse, a mechanical means, a hydraulic means, a delay mechanism that
is configured to interact with a fracture treatment (injection into
the well of high pressure water to fracture the formation), and a
delay mechanism configured to preferentially orient banks of
charges to fire in conjunction with a fracture treatment. The
mechanism interacts with the fracture by providing delay that would
detonate the charges during or after a fracing treatment operation
has occurred.
[0025] The shaped charges may be of any type utilized in wellbore
perforation. They be deep penetrating charges, big hole charges,
punch charges designed for limited penetration, reactive liner
technology charges or linear charges that produce slot shaped
holes. These type charges are well known to those skilled in the
art. For example there are Razor deep penetrating charges.
Interactive charges are described in publications available at
http://www.perf.com/publications/. See also
http://www.perf.com/chart.
Schlumberger describes its PowerJet Omega.TM. charge at
http://www.slb.com/services/completions/perforating/gun
systems/hollow carrier/powerjet omega deep charge.aspx.
[0026] Halliburton describes a variety of shaped charges at
http://www.halliburton.com/en-US/ps/wireline-perforating/wireline-and-per-
forating/perforating-services/shaped-charges/perforating-shaped-charges.
It should be appreciated by those skilled in the art that the shock
loading or perforating charges may be replaced with propellant or
some other energetic materials to shock load the geological
formation in a manner to induce initial fractures that the
hydraulic fractures will follow. It is not always necessary to
perforate the formation, shock loading will be sufficient to direct
the hydraulic fracture. Shape charges may be too large for some
open hole applications and other propellants can be effectively
used. It will in some applications, be sufficient to fill the body
of the tool with propellant that when detonated will provide the
necessary shock loading.
[0027] Punch charges are also referred to as circulation charges
and are selected for a specific tubing/casing thickness. Puncher
charges are designed to minimize/avoid outer casing damage and loss
of integrity.
http://www.dynaenergetics.com/EN/shaped-charges/puncher-charges-en.html
[0028] In one embodiment the invention is a firing head assembly
that comprises a pressure activated release mechanism, a firing
pin, an initiator percussion unit that ignites a detonation means
(such as a detonation cord), housed in a suitable body that can be
attached to or disposed in fins of perforating tools in a
configuration to allow the initiation of detonation of shape
charges located in the fins. The firing head is preferably easily
detachable from the tool, such as that shown at 240 in FIGS. 5 and
FIG. 7. The pressure activated release mechanism may be a rupture
disc, a shear pin retained firing system or other means that will
be apparent to those skilled in the art. The pressure activation
release mechanism has a preset pressure for release. In a single
tool with a multiplicity of fins the preset pressure may be set at
the same or different release pressure settings for the mechanisms
on the individual fins. They may be set at different pressure
settings for different fins. They may be set to fire at a given
pressure thereby allowing control of the orientation of the
perforation to the well bore. For example, If orientation and reset
pressure of the firing assembly on the fins is known the operator
can run at such pressure to only activate the desired fins such as
only the fins orientated on the upper or lower half, or any
combination thereof.
[0029] The firing heads may be modular and interchangeable from one
tool assembly to another and they may be configured to allow
different initiation means other than detonation cords such as
transmission from another fin firing head assembly.
[0030] Referring to FIG. 1 the tool of an embodiment of the
invention, 100, comprises a mandrel, 120, with couplings 110 A and
B on each end, a series of projections (blades or fins), 112,
disposed around the circumference of the mandrel. Disposed in each
of the fins is a firing mechanism means 101, a shear screw, 102,
mechanical blasting cap, 103, and a linear shape charge or a row of
perforating shape charges (such as the Razor.TM. line of charges,
see http://www.perf.com/razor/) 104, (see also FIG. 6). FIG. 2
shows a top and bottom view of the tool, 100, Illustrating the way
the blades are disposed around the outside circumference of the
mandrel. FIG. 4 is a perspective view of the tool, 100.
[0031] In another embodiment, shown in more detail in FIGS. 5-7,
the tool comprises a mandrel 201, having a firing head assembly,
240, disposed on each a plurality of fins 204, located around the
circumference of the mandrel. FIG. 6 is an end view of FIG. 5. FIG.
7 shows the components of the firing head. Item 242 is a reverse
acting rupture disc, 244 is a shear pin, 246 is a firing pin, 245,
is a firing head body that contains a firing pin. Item 248 is an
initiator percussion that ignites the detonation cord 210 that in
turn ignites the shape charges 206. The firing head assembly is an
embodiment of the invention.
[0032] The tool firing head mechanism is activated by predetermined
pressure (set point selected for the rupture disc). When the preset
pressure is reached, rupture disc 242 burst in each of the
assemblies, allowing increased pressure into the firing head
sub-assembly 240. At approximately the same time (a slight delay is
caused by shear pins 244 retaining the firing pin, 246) the firing
pin begins to travel towards a percussion initiator 248. Upon
impact of the percussion initiator, a detonator cord booster, 243,
is ignited which in turn ignites the detonator cord, 210. The
detonator cord passes underneath each shape charge ignition port
(206) causing the charge to detonate. The charge bursts through the
port plug 207 and into the geological formation.
[0033] In a given tool the pressure setting of the individual
rupture disc settings may be set at different pressure levels as
explained herein.
[0034] An important aspect of the tool of the invention (FIGS. 5-7)
is the ability to assemble the tool with the least amount of risk
as well as having a method of disassembly that does not involve
destructive means, thus providing a tool with great design
flexibility. The tool provides several options to make it well
suited for many different applications and operations. The
activation of the firing pin primarily relies on an accurate and
precisely controlled pressure reactive device (burst disc). The
pressure rating on the disc allows the tool to be set-up for many
options. With the proper set-up of rupture discs a system can be
held a constant annulus pressure (below the pressure that would be
required to hydraulically fracture), and still successfully
detonate all tools within a fracturing stage, either by precisely
controlling the rupture disc rating for the burst discs or setting
one rupture disc marginally lower than all others in either the
remaining fins on a single tool or the remaining tools in a stage.
The latter setup would utilize the pressure generated from the
initial fin's detonation providing a delayed detonation of a
majority of the charges. The tool also, preferably, uses a
detachable firing head that contains the initiation mechanism that
allows it to easily be replaced with other means of initiation.
Those additional initiation methods can incorporate time delays and
other improvements. The fin design itself can also be altered to
best create various perforation patterns into the well bore. The
design alterations include, but are not limited to, the orientation
of the fins (longitudinally, laterally, or helically), the number
of fins on a tool (only confined by the amount of available space
in the well annulus), and which of fins are installed to the tool
(as each fin is independent of the others). An additional feature,
depending on the casing size and well bore geometry, is that the
tool can be made as an integrated part of the casing string or as a
slip over system held in place by lock collars.
Operation
[0035] In operation the tool is, for example, set in line inside a
single stage of casing that contained two packers (142) and a
sliding sleeve (144) (FIGS. 8 and 9). Once the sliding sleeve is
actuated the tool is exposed to the now higher wellbore pressure.
Once a high enough annulus pressure is reached, a firing pin held
in place by shear screws or firing head assembly would release the
pin, impact a detonator and finally ignite perforating shaped
charge(s).
[0036] In an embodiment of the invention, the tool is activated by
annulus pressure around a liner string. In FIG. 1 the firing piston
(101) is held in place by shear screws (102) pinned higher than the
bottom hole (wellbore) pressure. When the frac sleeve is actuated
either by a ball or hydraulic pressure, the frac sleeve opens and
pressure is allowed to enter into the annulus of the wellbore. When
the frac pressure is increased above the bottom hole pressure, the
firing piston (101) will shear free and slide through a polished
bore and strike a mechanical blasting cap (103) which initiates the
detonation of a linear or round shape charge (104) that are located
in fins (112) that surround the circumference of the Tool. FIGS. 2
and 3 show end views of the tool shown in FIG. 1.
[0037] The method of which the first fin assembly would transfer
detonation in a secondary fin is accomplished by means of a
connection line that contains secondary detonation cord (see FIG.
6, item 145) thereby continuing a line of detonation transmission
to a secondary fin or by means of a pressure retaining line that
would use the blast pressure of the initial fin transferred through
the pressure retaining line into the firing head assembly of the
next fin.
[0038] The first tool that is set at the lowest activation
pressure, when it is initiated at its designed pressure to detonate
its shaped charges, creates blast pressure that will propagate
through the annulus of the well and initiate the function of
another similar tool in a stage; a secondary type tool inside the
same stage. In a similar fashion if two separate stages have
pressure communication between them the first tool's blast pressure
is used to initiate a similar tool in another stage. Likewise the
first tool's blasting pressure can be used to initiate the function
of a different tool in a different stage.
[0039] The tool is configured to be included into a well casing
string as shown in FIGS. 4, 8 and 9. FIGS. 8 and 9 illustrate how
the tool may be deployed in oil or gas wells. Packers, 142, seal
the space between them and that space constitutes a stage as the
term is used herein. Item 144 is a sliding sleeve. The tools may be
spaced as desired and located at predetermined location to achieve
perforations in desired locations.
[0040] In the foregoing specification, the invention has been
described with reference to specific embodiments thereof. It will,
however, be evident that various modifications and changes can be
made thereto without departing from the broader spirit and scope of
the invention as set forth in the appended claims. The
specification is, accordingly, to be regarded in an illustrative
rather than a restrictive sense. Therefore, the scope of the
invention should be limited only by the appended claims.
* * * * *
References