U.S. patent application number 13/675181 was filed with the patent office on 2014-03-06 for fracturing a well formation.
This patent application is currently assigned to North Schlumberger Oilfield Technologies (Xi'an) Co., Ltd.. The applicant listed for this patent is NORTH SCHLUMBERGER OILFIELD TECHNOLOGIES (X'AN) C. Invention is credited to Guofu Feng, Senyuan Li, Baoxing Wang, Changshuan Wang, Feng (Rock) Wang, Yuanwen Yao.
Application Number | 20140060839 13/675181 |
Document ID | / |
Family ID | 47367649 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140060839 |
Kind Code |
A1 |
Wang; Changshuan ; et
al. |
March 6, 2014 |
FRACTURING A WELL FORMATION
Abstract
A fracturing tool includes a container structure, and a puncher
charge arranged in the container structure, where the puncher
charge if detonated is configured to extend an opening through the
container structure without creating a perforation tunnel in a
formation surrounding the well. An energetic material is to be
initiated by detonation of the puncher charge, where the energetic
material upon initiation creates an increased pressure in the well
to perform fracturing of the formation.
Inventors: |
Wang; Changshuan; (Xi'an,
CN) ; Yao; Yuanwen; (Xi'an, CN) ; Li;
Senyuan; (Xi'an, CN) ; Feng; Guofu; (Xi'an,
CN) ; Wang; Feng (Rock); (Xi'an, CN) ; Wang;
Baoxing; (Xi'an, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NORTH SCHLUMBERGER OILFIELD TECHNOLOGIES (X'AN) C |
Xi'an |
|
CN |
|
|
Assignee: |
North Schlumberger Oilfield
Technologies (Xi'an) Co., Ltd.
Xi'an
CN
|
Family ID: |
47367649 |
Appl. No.: |
13/675181 |
Filed: |
November 13, 2012 |
Current U.S.
Class: |
166/299 ;
166/63 |
Current CPC
Class: |
E21B 43/117 20130101;
E21B 43/263 20130101 |
Class at
Publication: |
166/299 ;
166/63 |
International
Class: |
E21B 43/263 20060101
E21B043/263 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2012 |
CN |
201210327368.X |
Claims
1. A fracturing apparatus for use in a well, comprising: a
container structure; a puncher charge arranged in the container
structure, where the puncher charge if detonated is configured to
extend an opening through the container structure without creating
a perforation tunnel in a formation surrounding the well; and an
energetic material to be initiated by detonation of the puncher
charge, where the energetic material upon initiation creates an
increased pressure in the well to perform fracturing of the
formation.
2. The fracturing apparatus of claim 1, further comprising an outer
housing, wherein the container structure is located inside the
outer housing.
3. The fracturing apparatus of claim 2, wherein the energetic
material is between the outer housing and the container
structure.
4. The fracturing apparatus of claim 2, further comprising a
loading tube carrying the puncher charge, the loading tube being
inside the container structure, wherein the container structure is
to provide protection of an assembly including the loading tube and
puncher charge from well pressure.
5. The fracturing apparatus of claim 2, wherein the outer housing
has an opening that exists prior to detonation of the puncher
charge, wherein the opening provides for fluid communication
between an inner chamber of the outer housing and the well.
6. The fracturing apparatus of claim 1, wherein the container
structure is an outer housing of the fracturing apparatus.
7. The fracturing apparatus of claim 6, wherein the container
structure has a scalloped region through which an explosive force
of the puncher charge is to extend to create an opening in the
container structure.
8. The fracturing apparatus of claim 6, further comprising a
loading tube carrying the puncher charge, where the energetic
material is between the loading tube and the container
structure.
9. The fracturing apparatus of claim 1, wherein the energetic
material is selected from the group consisting of a propellant, a
high explosive, a gun powder, a combustible metallic powder,
thermite, or a combination thereof.
10. The fracturing apparatus of claim 1, wherein the well is lined
with a casing or liner, and wherein the puncher charge if detonated
is configured to extend the opening through the container structure
without perforating the casing or liner.
11. The fracturing apparatus of claim 1, wherein the energetic
material is part of a mixture that further includes at least one
selected from the group consisting of proppants, a solid acid, a
bactericide, and a combination thereof.
12. A method of forming a fracturing apparatus for use in
fracturing a formation around a well, comprising: providing a
container structure; arranging puncher charges inside the container
structure, wherein the puncher charges if detonated extend openings
through the container structure without creating perforation
tunnels in the formation; and providing an energetic material in
the fracturing apparatus to be initiated by detonation of the
puncher charges.
13. The method of claim 12, further comprising ballistically
connecting a detonating cord to the puncher charges.
14. The method of claim 12, further comprising arranging the
puncher charges within a loading tube that is inside the container
structure.
15. The method of claim 12, further comprising providing the
container structure and the energetic material inside an outer
housing that has pre-configured openings to allow fluid
communication between the well and an inner chamber of the outer
housing.
16. The method of claim 12, wherein the container structure is a
scalloped outer housing having thinned wall regions through which
the puncher charges are to extend openings upon detonation of the
puncher charges.
17. A system comprising: a tool string for deployment into a well,
the tool string having a fracturing tool, the fracturing tool
comprising: a container structure; a puncher charge arranged in the
container structure, where the puncher charge if detonated is
configured to extend an opening through the container structure
without creating a perforation tunnel in a formation surrounding
the well; and an energetic material to be initiated by detonation
of the puncher charge, where the energetic material upon initiation
creates an increased pressure in the well to perform fracturing of
the formation.
18. The system of claim 17, wherein the energetic material is
selected from the group consisting of a propellant, a high
explosive, a gun powder, a combustible metallic powder, thermite,
or a combination thereof.
19. The system of claim 17, wherein the fracturing tool further
comprises an outer housing in which the container structure is
located, the outer housing having an opening.
20. The system of claim 17, wherein the container structure is a
scalloped outer housing.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This claims priority under 35 U.S.C .sctn.119(e) of Chinese
Patent Application No. 201210327368.X, filed Sep. 6, 2012, which is
hereby incorporated by reference.
BACKGROUND
[0002] Fracturing can be performed in a subterranean formation to
propagate fractures in the formation. The fractures provide
passageways in the formation through which fluids can flow to or
from a well (for production or injection operations, respectively).
Fracturing the formation improves the fluid transmissivity of the
formation, such that more efficient fluid production can be
accomplished.
SUMMARY
[0003] In general, according to some implementations, a fracturing
apparatus for use in a well includes a container structure, a
puncture charge arranged in the container structure, where the
puncher charge if detonated is configured to extend an opening
through the container structure without creating a perforation
tunnel in a formation surrounding the well. Additionally, the
fracturing apparatus includes an energetic material to be initiated
by detonation of the puncher charge, where the energetic material
upon initiation creates increased pressure in the well to perform
fracturing of the formation.
[0004] Other or alternative features will become apparent from the
following description, from the claims, and from the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Some embodiments are described with respect to the following
figures:
[0006] FIGS. 1 and 3 are partial sectional views of fracturing
tools according to some implementations;
[0007] FIG. 2 is a cross-sectional view of a portion of the
fracturing tool of FIG. 1, in accordance with some
implementations;
[0008] FIG. 4 illustrates an example tool string having a
fracturing tool configured according to some implementations;
and
[0009] FIG. 5 is a flow diagram of a process of forming a
fracturing tool according to some implementations.
DETAILED DESCRIPTION
[0010] To fracture a formation surrounding a well, a fracturing
tool can be deployed into the well. The fracturing tool can have an
energetic material that upon initiation produces increased pressure
in the well, where the increased pressure is provided to perform
fracturing in the formation. Generally, fracturing the formation
helps to improve fluid communication characteristics of the
formation. Fracturing also helps to relieve plugging of
communications channels in the formation due to debris.
Additionally, formation breakdown pressure can be reduced.
[0011] Traditional fracturing tools are designed for relatively
shallow wells, such as wells with depths less than 5,000 meters
(m). At depths greater than 5,000 m (and sometimes even greater
than 7,500 m or 10,000 m), relatively high downhole temperatures
and pressures can raise various issues relating to reliability of a
fracturing tool. To withstand elevated downhole pressures in a deep
well, for example, a container structure can be provided to carry
components that may be sensitive to the elevated downhole
pressures. However, if improperly designed, the container structure
may not be properly broken apart during operation, which can
prevent initiation of an energetic material of the fracturing
tool.
[0012] In other designs, an initiating material can be provided on
the outside of the housing of a tool, such as in the form of a
sleeve formed of the initiating material that can be fitted around
the tool housing. However, such designs may suffer from inadvertent
self-ignition of the initiating material due to friction between
the initiating material and an inner wall of the well during
deployment of the tool.
[0013] In accordance with some implementations, fracturing tools
are provided that are able to operate in relatively deep wells,
such as wells having depths of greater than 5,000 m, 7,500 m, or
10,000 m. In other examples, fracturing tools according to some
implementations can also be used in relatively shallow wells. In
some implementations, a fracturing tool can use an energetic
material that is able to withstand the relatively high temperatures
and high pressures of a relatively deep well. In other
implementations, a sealed housing can be provided to protect the
energetic material from elevated downhole temperature and pressure
conditions, such that the energetic material having reduced
temperature and pressure ratings may be used. In addition, a
relatively reliable ignition mechanism can be provided in the
fracturing tool to ignite the energetic material.
[0014] In some implementations, the energetic material can include
any one or combination of the following: a propellant, a high
explosive, a gun powder, a combustible metallic powder, and
thermite. The energetic material upon initiation is designed to
burn, which produces increased pressure in a well interval
proximate the fracturing tool. In further implementations, the
energetic material can be part of a mixture that further includes
proppants, a solid acid, a bactericide (a disinfectant for
suppressing bacteria growth in a well), and other materials.
[0015] FIG. 1 is a partial sectional view of a fracturing tool 100
in accordance with some implementations. The fracturing tool 100
has a slotted outer housing 102, which has various openings 104.
The outer housing 102 can be a metallic housing or a non-metallic
housing. The openings 104 are preconfigured or pre-manufactured in
the slotted housing 102; in other words, the openings 104 are
present in the slotted housing 102 prior to detonation of an
explosive element of the fracturing tool 100, as discussed further
below.
[0016] A first end of the slotted housing 102 is connected to a
firing head 106, which can be activated to initiate detonation of
an explosive element in the fracturing tool 100. The firing head
106 can be activated by any one of various types of stimuli. For
example, the firing head 106 can be electrically activated, such as
by transmission of an electrical signal over an electrical cable
that is attached to the firing head 106. In other examples, the
firing head 106 can be activated using an optical signal provided
over an optical cable, by a pressure stimulus, by a mechanical
stimulus, and so forth.
[0017] The lower end of the fracturing tool 100 is connected to a
bottom nose 108, or to some other structure.
[0018] The slotted outer housing 102 defines an inner chamber 110.
Various components are contained in the inner chamber 110,
including an energetic material 112, and an energetic material
initiation assembly 114 according to some implementations. The
energetic material 112 can be any one of the various example
energetic materials listed above. The energetic material 112 is
positioned to surround the initiation assembly 114 inside the
chamber 110. In some examples, the energetic material 112 can
withstand high temperatures (e.g. temperatures greater than
300.degree. F.) or ultra-high temperatures (e.g. temperatures
greater than 500.degree. F.).
[0019] The energetic material 112 can be formed of a particulate or
powder material. Alternatively, the energetic material can be a
solid material having a certain shape, such as a cubic shape,
spherical shape, or other shape. In further examples, the energetic
material 112 can be formed of a liquid, which can be provided in
implementations where the outer housing 102 does not have openings
104 (such as implementations according to FIG. 3 discussed further
below).
[0020] The energetic material 112 can be formed of a
water-resistant material. Alternatively, the energetic material 112
can be non-water-resistant, which can be used in the FIG. 3
implementation, for example.
[0021] The initiation assembly 114 includes a container structure
116, a loading tube 118 inside the container structure 116, and
puncher charges 120 inside the loading tube 118. More specifically,
the container structure 116 can be a central tube, in which the
loading tube 118 is arranged. Since the central tube 116 is
provided in the slotted outer housing 102, the central tube 116 is
sealed to protect components inside the central tube 116. The
central tube 116 and the loading tube 118 can each be formed of a
metallic material or a non-metallic material.
[0022] A cross-sectional view of a portion of the fracturing tool,
along section 2-2, is depicted in FIG. 2. According to the example
of FIGS. 1 and 2, the slotted outer housing 102, central tube 116,
and loading tube 118 are generally cylindrical in shape. In other
implementations, one or more of the foregoing structures can have
other cross-sectional shapes, including non-circular
cross-sectional shapes.
[0023] The central tube 116 has a larger pressure rating than the
loading tube 118, such that the central tube 116 can withstand
larger well pressures. The central tube 116 serves to protect
components inside the central tube 116 from the increased downhole
pressures that may be present in a relatively deep well. Note that
the inner chamber 110 of the slotted outer housing 102 is in fluid
communication with the well due to presence of the openings
104.
[0024] The puncher charges 120 upon detonation are able to create
openings in the loading tube 118 and the container structure 116.
However, the puncher charges 120 have relatively low explosive
power as compared to perforating shaped charges, which are designed
to produce perforating jets that have enough power to perforate any
surrounding casing or liner and extend perforation tunnels into the
formation surrounding the well in which the fracturing tool 100 is
provided.
[0025] In contrast, the puncher charges 120 are configured without
sufficient explosive power to produce perforating jets to perforate
the surrounding casing or liner and extend perforation tunnels in
the surrounding formation. As a result, using the fracturing tool
100 according to some implementations, fracturing operations can be
performed without causing perforation damage to the casing or liner
and the surrounding formation.
[0026] As depicted in the example of FIG. 1, the puncher charges
120 can be arranged to point in various different directions. For
example, the puncher charges 120 can have a spiral pattern along
the length of the fracturing tool 100. In other examples, the
puncher charges 120 can have different arrangements.
[0027] The puncher charges 120 are ballistically connected to a
detonating cord 122. The detonating cord 122 is ballistically
coupled to the firing head 106, and the detonating cord 122 is
initiated by the firing head 106. Upon initiation of the detonating
cord 122, the puncher charges 120 are detonated, which causes the
puncher charges 120 to produce explosive forces along respective
directions to extend openings through the loading tube 118 and
central tube 116.
[0028] The explosive force of the puncher charges 120 is provided
to also initiate the energetic material 112. Initiation of the
energetic material 112 produces increased pressure in the well
interval surrounding the fracturing tool 100. For example, if the
energetic material 112 is implemented with a propellant, initiation
of the propellant causes the propellant to burn, which produces
gases that increases the pressure in the well interval surrounding
the fracturing tool 100. The increased pressure in the well
interval surrounding the fracturing tool 100 is sufficient to
extend fractures in the surrounding formation.
[0029] A relatively reliable initiation assembly 114 is thus
provided for initiating the energetic material 112, even in the
presence of relatively high downhole pressures in deep wells. Also,
since the energetic material 112 is contained within the outer
housing 102, inadvertent initiation of the energetic material 112
due to frictional contact can be avoided.
[0030] FIG. 3 depicts a fracturing tool 100-1 according to
different implementations. In FIG. 3, components that are similar
to the corresponding components in FIG. 1 are assigned the same
reference numerals. The fracturing tool 100-1 has a scalloped outer
housing 302, which is not preconfigured or pre-manufactured with
openings as is the case with the slotted outer housing 102 of FIG.
1. Instead, the scalloped outer housing 302 has scalloped regions
304, which are regions of the wall of the scalloped outer housing
302 that are thinner than remaining parts of the wall of the
housing 302. The scalloped regions 304 are designed to allow for
puncher charges 120 of the fracturing tool 300 to more easily punch
openings in the scalloped outer housing 302, upon detonation of the
puncher charges 120. The scalloped regions 304 can have various
shapes, such as a round shape, rectangular shape, oval shape, or
any other shape.
[0031] In other implementations, the outer housing 302 can be
without the scalloped regions 304 of FIG. 3 or without the openings
104 of FIG. 1. Such an outer housing 302 has a regular wall
width.
[0032] An energetic material 112 is provided in the inner chamber
of the scalloped outer housing 302. Since the scalloped outer
housing 302 is sealed against the external well fluids, the
energetic material 112 used in the fracturing tool 100-1 of FIG. 3
can have a lower pressure rating than the energetic material 112
used in the fracturing tool of FIG. 1. As a result, greater
flexibility in selection of the energetic material 112 can be
provided with the fracturing tool 100-1 of FIG. 3, since the
energetic material is no longer exposed to well fluids.
[0033] The energetic material 112 is provided around an energetic
material initiation assembly 114-1, which is similar to the
initiation assembly 114 of FIG. 1 except that the central tube 116
of FIG. 1 is omitted. Instead, the initiation assembly 114-1
includes just the loading tube 118 and puncher charges 120 and
detonating cord 122 inside the loading tube 118. The central tube
116 in the fracturing tool 100 of FIG. 1 can be omitted in the
fracturing tool 100-1 of FIG. 3 since the scalloped outer housing
302 protects the initiation assembly 114-1 from external well fluid
pressure.
[0034] Effectively, in implementations according to FIG. 3, the
scalloped outer housing 302 provides the container structure for
protecting components inside the scalloped outer housing 302 from
the elevated downhole pressures.
[0035] In operation of the fracturing tool 100-1, upon initiation
of the detonating cord 122 by the firing head 106, the puncher
charges 120 are detonated, which causes explosive forces to break
through the loading tube 118 and also to extend openings through
the scalloped regions 304 of the scalloped outer housing 302. In
addition, detonation of the puncher charges 120 causes initiation
of the energetic material 112. The energetic material 112 upon
initiation produces elevated pressure, which can be communicated
through the openings created through the scalloped regions 304 into
the surrounding well interval. The elevated pressure is designed to
fracture the surrounding formation.
[0036] FIG. 4 illustrates a tool string that is lowered into a well
402. The well 402 can be lined with casing or liner 404, which has
been previously perforated with perforations 409. The surrounding
formation also has perforation tunnels 411 that resulted from a
perforating operation. Alternatively, the tool string can be used
in an open hole section of the well 402, where the open hole
section is unlined. Although the well 402 is shown as being
deviated in the FIG. 4 example, it is noted that in other examples,
the well 402 can be a vertical well or a horizontal well. The tool
string is lowered on a deployment structure 406, which can be a
wireline, tubing (e.g. coiled tubing or other tubing), a pipe, a
slickline, and so forth. The tool string has a fracturing tool 408
(which can be the fracturing tool 100 or 100-1 depicted in FIG. 1
or 3, respectively). Activation of the firing head 106 (FIG. 1 or
3) of the fracturing tool 100 or 100-1 can be in response to
various stimuli that can be sent from equipment at the earth
surface 418 to the firing head 106.
[0037] FIG. 5 is a flow diagram of a process of forming a
fracturing tool (100 or 100-1 of FIG. 1 or 3) according to some
implementations. A container structure (116 or 302 of FIG. 1 or 3)
is provided (at 502). A puncher charge (120 in FIG. 1 or 3) is
arranged (at 504) in the container structure. In addition, an
energetic material (112 in FIG. 1 or 3) to be initiated by the
puncher charge is provided (at 506) in the fracturing tool.
[0038] In the foregoing description, numerous details are set forth
to provide an understanding of the subject disclosed herein.
However, implementations may be practiced without some or all of
these details. Other implementations may include modifications and
variations from the details discussed above. It is intended that
the appended claims cover such modifications and variations.
* * * * *