U.S. patent application number 15/524304 was filed with the patent office on 2017-11-23 for method for well completion.
The applicant listed for this patent is SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Grant GEORGE, Derek INGRAHAM, Shane SARGENT.
Application Number | 20170335667 15/524304 |
Document ID | / |
Family ID | 55909728 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170335667 |
Kind Code |
A1 |
SARGENT; Shane ; et
al. |
November 23, 2017 |
METHOD FOR WELL COMPLETION
Abstract
The disclosure pertains to methods for completing a well
comprising locating a production tubing having a plurality of
sleeve valves, each having a sliding sleeve therein within a well
bore and locating a tool operable to open said plurality of sleeve
valves within said production tubing. The method further comprises
repeating for at least one of said plurality of sleeve valves the
steps of opening a one of said plurality of sleeve valves with said
tool, performing a fracturing operation and closing said one of
said plurality of sleeve valves.
Inventors: |
SARGENT; Shane; (Calgary,
CA) ; GEORGE; Grant; (Calgary, CA) ; INGRAHAM;
Derek; (Aberdeen, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHLUMBERGER TECHNOLOGY CORPORATION |
Sugar Land |
TX |
US |
|
|
Family ID: |
55909728 |
Appl. No.: |
15/524304 |
Filed: |
November 4, 2015 |
PCT Filed: |
November 4, 2015 |
PCT NO: |
PCT/US2015/058924 |
371 Date: |
May 4, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62075027 |
Nov 4, 2014 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/14 20130101;
E21B 43/26 20130101; E21B 2200/06 20200501; E21B 34/14 20130101;
E21B 43/14 20130101 |
International
Class: |
E21B 43/26 20060101
E21B043/26; E21B 34/14 20060101 E21B034/14; E21B 43/14 20060101
E21B043/14; E21B 33/14 20060101 E21B033/14 |
Claims
1. A method for performing a fracturing operation on a rock
formation surrounding a wellbore, the method comprising: locating a
production tubing having a plurality of sleeve valves, each having
a sliding sleeve therein within a well bore; locating a tool
operable to open said plurality of sleeve valves within said
production tubing; and repeating for at least one of said plurality
of sleeve valves the steps of: opening a one of said plurality of
sleeve valves with said tool, performing a fracturing operation;
and closing said one of said plurality of sleeve valves.
2. The method of claim 1 wherein said tool is located within said
sleeve valve before opening said sleeve valve.
3. The method of claim 1 wherein said opening of one of a plurality
of sleeve valves comprises extending at least one key from said
tool into engagement with said sliding sleeve and slidably shifting
said sliding sleeve longitudinally within said well to open said
one of said plurality of sleeve valves.
4. The method of claim 1 wherein said closing of one of a plurality
of sleeve valves comprises slidably shifting said sliding sleeve
longitudinally within said well to close said one of said plurality
of sleeve valves and retracting at least one key from said tool
into engagement with said sliding sleeve.
5. The method of claim 1 wherein said plurality of sleeve valves
are opened, have a fracturing operation performed therethrough and
closed starting at the top most sleeve valve and ending with a
bottom most sleeve valve.
6. The method of claim 5 further comprising opening all of said
plurality of sleeve valves as said tool is retracted from said well
for subsequent production of said well.
7. The method of claim 1 wherein said tool remains within said
production casing during said fracturing operation.
8. The method of claim 7 wherein said tool remains within said
sleeve valve during said fracturing operation.
9. The method of claim 1 further comprising cementing said
production casing within said well.
10. The method of claim 9 wherein an annular cavity between said
production casing and said well is clear of packers.
Description
CROSS REFERENCE PARAGRAPH
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/075,027, entitled "WELL COMPLETION," filed Nov.
4, 2014, the disclosure of which is hereby incorporated herein by
reference.
BACKGROUND
Field
[0002] The present disclosure relates to well completion in general
and in particular to a method for performing a fracture operation
on a well.
Description of Related Art
[0003] Hydrocarbon fluids such as oil and natural gas are obtained
from a subterranean geologic formation, referred to as a reservoir,
by drilling a well that penetrates the hydrocarbon-bearing
formation. Once a wellbore is drilled, various forms of well
completion components may be installed in order to control and
enhance the efficiency of producing the various fluids from the
reservoir.
[0004] Fracturing is used to increase permeability of subterranean
formations. A fracturing fluid is injected into the wellbore
passing through the subterranean formation. A propping agent
(proppant) is injected into the fracture to prevent fracture
closing and, thereby, to provide improved extraction of extractive
fluids, such as oil, gas or water.
[0005] The disclosure pertains to methods of treating an
underground formation penetrated by either vertical wells or wells
having a substantially horizontal section. Horizontal well in the
present context may be interpreted as including a substantially
horizontal portion, which may be cased or completed open hole,
wherein the fracture is transversely or longitudinally oriented and
thus generally vertical or sloped with respect to horizontal. The
following disclosure will be described using horizontal well but
the methodology is equally applicable to vertical wells.
[0006] The industry has privileged, when it comes to hydraulic
fracturing, what is known as being "plug-and-perf" technique.
Horizontal wells may extend hundreds of meters away from the
vertical section of the wellbore. Most of the horizontal section of
the well passes through the producing formation and are completed
in stages. The wellbore begins to deviate from vertical at the
kickoff point, the beginning of the horizontal section is the heel
and the farthest extremity of the well is the toe. Engineers
perform the first perforating operation at the toe, followed by a
fracturing treatment. Engineers then place a plug in the well that
hydraulically isolates the newly fractured rock from the rest of
the well. A section adjacent to the plug undergoes perforation,
followed by another fracturing treatment. This sequence is repeated
many times until the horizontal section is stimulated from the toe
back to the heel. Finally, a milling operation removes the plugs
from the well and production commences.
[0007] The common practice in the art is to perforate 4-6 clusters,
and push a slickwater laden fluid at or above fracture pressure to
create fractures; it is estimated that 30 to 60% of these
perforations do not produce due to for example screen out,
geological constraint, etc., and thus for every 100 perforations in
a wellbore, commonly only 30 to 70 of the conventional perforations
are useful for production.
[0008] To respond to that, some operations now involve what is
known as pin-point fracturing, which may be defined as the
operation of pumping a fluid above the fracturing pressure of the
formation to be treated through a single entry. The entry may be a
perforation, a valve, a sleeve, or a sliding sleeve. Generally,
sliding sleeves in the closed position are fitted to the production
liner. The production liner is placed in a hydrocarbon formation.
An object is introduced into the wellbore from surface, and the
object is transported to the target zone by the flow field or
mechanically, for example using a wireline or a coiled tubing. When
at the target location, the object is caught by the sliding sleeve
and shifts the sleeve to the open position. A sealing device, such
as a packer or cups, is positioned below the sleeve to be treated
in order to isolate the lower portion of the wellbore. The sealing
device is set, fluid is pumped into the fracture and then the
sealing device is unset and moved below the next zone (or sleeve)
to be treated. Representative examples of sleeve-based systems are
disclosed in U.S. Pat. No. 7,387,165, U.S. Pat. No. 7,322,417, U.S.
Pat. No. 7,377,321, US 2007/0107908, US 2007/0044958, US
2010/0209288, U.S. Pat. No. 7,387,165, US2009/0084553, U.S. Pat.
No. 7,108,067, U.S. Pat. No. 7,431,091, U.S. Pat. No. 7,543,634,
U.S. Pat. No. 7,134,505, U.S. Pat. No. 7,021,384, U.S. Pat. No.
7,353,878, U.S. Pat. No. 7,267,172, U.S. Pat. No. 7,681,645, U.S.
Pat. No. 7,066,265, U.S. Pat. No. 7,168,494, U.S. Pat. No.
7,353,879, U.S. Pat. No. 7,093,664, and U.S. Pat. No. 7,210,533,
which are hereby incorporated herein by reference. A fracturing
treatment is then circulated down the wellbore to the formation
adjacent the open sleeve.
[0009] Improvements in completing these unconventional formations
would be welcome by the industry.
SUMMARY
[0010] In embodiments the disclosure pertains to methods for
completing a well comprising completing at least a zone of a first
well using a pin-point fracturing technique without using a sealing
element.
[0011] According to a first embodiment there is disclosed a method
for performing a fracturing operation on a rock formation
surrounding a wellbore, the method comprising locating a production
tubing having a plurality of sleeve valves, each having a sliding
sleeve therein within a well bore and locating a tool operable to
open said plurality of sleeve valves within said production tubing.
The method further comprises repeating for at least one of said
plurality of sleeve valves the steps of opening a one of said
plurality of sleeve valves with said tool, performing a fracturing
operation and closing said one of said plurality of sleeve
valves.
[0012] The tool may be located within the sleeve valve before
opening the sleeve valve. The opening of one of a plurality of
sleeve valves may comprise extending at least one key from the tool
into engagement with the sliding sleeve and slidably shifting the
sliding sleeve longitudinally within the well to open the one of
the plurality of sleeve valves. The closing of one of a plurality
of sleeve valves may comprise slidably shifting the sliding sleeve
longitudinally within the well to close the one of the plurality of
sleeve valves and retracting at least one key from the tool into
engagement with the sliding sleeve.
[0013] The plurality of sleeve valves may be opened, may have a
fracturing operation performed therethrough and closed starting at
the top most sleeve valve and ending with a bottom most sleeve
valve. The method may further comprise opening all of the plurality
of sleeve valves as the tool is retracted from the well for
subsequent production of the well.
[0014] The tool may remain within the production casing during the
fracturing operation. The tool may remain within the sleeve valve
during the fracturing operation. The method may further comprise
cementing the production casing within the well. An annular cavity
between the production casing and the well may be clear of
packers.
[0015] Other aspects and features of the present disclosure will
become apparent to those ordinarily skilled in the art upon review
of the following description of specific embodiments of the
invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Certain embodiments of the disclosure will hereafter be
described with reference to the accompanying drawings, wherein like
reference numerals denote like elements. It should be understood,
however, that the accompanying drawings illustrate only the various
implementations described herein and are not meant to limit the
scope of various technologies described herein. The drawings show
and describe various embodiments of the current disclosure.
[0017] FIG. 1 is a cross-sectional view of a wellbore having a
plurality of flow control valves according to a first embodiment of
the present invention located therealong.
[0018] FIG. 2 is a cross sectional view of a control valves of for
use in the system of FIG. 1.
[0019] FIG. 3 is a longitudinal cross-sectional view of the control
valve of FIG. 2 as taken along the line 3-3.
[0020] FIG. 4 is a detailed cross-sectional view of the extendable
ports of the valve of FIG. 2 in a first or retracted position.
[0021] FIG. 5 is a detailed cross-sectional view of the extendable
ports of the valve of FIG. 2 in a second or extended position with
the sleeve valve in an open position.
[0022] FIG. 6 is a cross sectional view of the valve of FIG. 2 as
taken along the line 3-3 showing a shifting tool located
therein.
[0023] FIG. 7 is an axial cross-sectional view of the shifting tool
of FIG. 6 as taken along the line 7-7.
[0024] FIG. 8 a lengthwise cross sectional view of the shifting
tool of FIG. 6 taken along the line 8-8 in FIG. 7 with a control
valve located therein according to one embodiment with the sleeve
engaging members located at a first or retracted position.
[0025] FIG. 9 is a cross sectional view of the shifting tool of
FIG. 6 taken along the line 8-8 with a control valve located
therein according to one embodiment with the sleeve engaging
members located at a second or extended position
[0026] FIG. 10 is a perspective view of a shifting tool according
to a further embodiment.
[0027] FIG. 11 is a side view of a well at a first step of engaging
a first sleeve valve according to the present method.
[0028] FIG. 12 is a side view of a well at a second step of opening
and performing a fracturing operation through a first sleeve valve
according to the present method.
[0029] FIG. 13 is a side view of a well at a third step of engaging
a second sleeve valve according to the present method.
[0030] FIG. 14 is a side view of a well at a final step of drawing
the tool out of a bottom of the well according to the present
method.
DETAILED DESCRIPTION
[0031] At the outset, it should be noted that in the development of
any such actual embodiment, numerous implementation--specific
decisions must be made to achieve the developer's specific goals,
such as compliance with system related and business related
constraints, which will vary from one implementation to another.
Moreover, it will be appreciated that such a development effort
might be complex and time consuming but would nevertheless be a
routine undertaking for those of ordinary skill in the art having
the benefit of this disclosure. In addition, the composition
used/disclosed herein can also comprise some components other than
those cited. In the summary and this detailed description, each
numerical value should be read once as modified by the term "about"
(unless already expressly so modified), and then read again as not
so modified unless otherwise indicated in context. Also, in the
summary and this detailed description, it should be understood that
a concentration range listed or described as being useful,
suitable, or the like, is intended that any and every concentration
within the range, including the end points, is to be considered as
having been stated. For example, "a range of from 1 to 10" is to be
read as indicating each and every possible number along the
continuum between about 1 and about 10. Thus, even if specific data
points within the range, or even no data points within the range,
are explicitly identified or refer to only a few specific, it is to
be understood that inventors appreciate and understand that any and
all data points within the range are to be considered to have been
specified, and that inventors possessed knowledge of the entire
range and all points within the range.
[0032] The statements made herein merely provide information
related to the present disclosure and may not constitute prior art,
and may describe some embodiments illustrating the disclosure.
[0033] In the specification and appended claims: the terms
"connect", "connection", "connected", "in connection with", and
"connecting" are used to mean "in direct connection with" or "in
connection with via one or more elements"; and the term "set" is
used to mean "one element" or "more than one element". Further, the
terms "couple", "coupling", "coupled", "coupled together", and
"coupled with" are used to mean "directly coupled together" or
"coupled together via one or more elements". As used herein, the
terms "up" and "down", "upper" and "lower", "upwardly" and
downwardly", "upstream" and "downstream"; "above" and "below"; and
other like terms indicating relative positions above or below a
given point or element are used in this description to more clearly
describe some embodiments of the disclosure.
[0034] Embodiments herein relate to methods of completing an
underground formation using multi-stage pin-point fracturing for
treating a well without using any sealing element.
[0035] Referring to FIG. 1, a wellbore 10 is drilled into the
ground 8 to a production zone 6 by known methods. The production
zone 6 may contain a horizontally extending hydrocarbon bearing
rock formation or may span a plurality of hydrocarbon bearing rock
formations such that the wellbore 10 has a path designed to cross
or intersect each formation. As illustrated in FIG. 1, the wellbore
includes a vertical section 12 having a valve assembly or Christmas
tree 14 at a top end thereof and a bottom or production section 16
which may be horizontal or angularly oriented relative to the
horizontal located within the production zone 6. After the wellbore
10 is drilled the production tubing 20 is of the hydrocarbon well
is formed of a plurality of alternating liner or casing 22 sections
and in line valve bodies 24 surrounded by a layer of cement 23
between the casing and the wellbore. The valve bodies 24 are
adapted to control fluid flow from the surrounding formation
proximate to that valve body and may be located at predetermined
locations to correspond to a desired production zone within the
wellbore. In operation, between 8 and 100 valve bodies may be
utilized within a wellbore although it will be appreciated that
other quantities may be useful as well.
[0036] Turning now to FIG. 2, a perspective view of one valve body
24 is illustrated. The valve body 24 comprises a substantially
elongate cylindrical outer casing 26 extending between first and
second ends 28 and 30, respectively and having a central passage 32
therethrough. The first end 28 of the valve body is connected to
adjacent liner or casing section 22 with an internal threading in
the first end 28. The second end 30 of the valve body is connected
to an adjacent casing section with external threading around the
second end 30. The valve body 24 further includes a central portion
34 having a plurality of raised sections 36 extending axially
therealong with passages 37 therebetween. As illustrated in the
accompanying figures, the valve body 24 has three raised sections
although it will be appreciated that a different number may also be
utilized.
[0037] Each raised section 36 includes a radially movable body or
port body 38 therein having an aperture 40 extending therethrough.
The aperture 40 extends from the exterior to the interior of the
valve body and is adapted to provide a fluid passage between the
interior of the bottom section 16 and the wellbore 10 as will be
further described below. The aperture 40 may be filled with a
sealing body (not shown) when installed within a bottom section 16.
The sealing body serves to assist in sealing the aperture until the
formation is to be fractured and therefore will have sufficient
strength to remain within the aperture until that time and will
also be sufficiently frangible so as to be fractured and removed
from the aperture during the fracing process. Additionally, the
port bodies 38 are radially extendable from the valve body so as to
engage an outer surface thereof against the wellbore 10 so as to
center the valve body 24 and thereby the production section within
the wellbore.
[0038] Turning now to FIG. 3, a cross sectional view of the valve
body 24 is illustrated. The central passage 32 of the valve body
includes a central portion 42 corresponding to the location of the
port bodies 38. The central portion is substantially cylindrical
and contains a sliding sleeve 44 therein. The central portion 42 is
defined between first or entrance and second or exit raised
portions or annular shoulders, 46 and 48, respectively. The sliding
sleeve 44 is longitudinally displaceable within the central portion
42 to either be adjacent to the first or second shoulder 46 or 48.
At a location adjacent to the second shoulder, the sliding sleeve
44 sealably covers the apertures 40 so as to isolate the interior
from the exterior of the bottom section 16 from each other, whereas
when the sliding sleeve 44 is adjacent to the first shoulder 46,
the sliding sleeve
[0039] The central portion 42 includes a first annular groove 50 a
therein proximate to the first shoulder 46. The sliding sleeve 44
includes a radially disposed snap ring 52 therein corresponding to
the groove 50 a so as to engage therewith and retain the sliding
sleeve 44 proximate to the first shoulder 46 which is an open
position for the valve body 24. The central portion 42 also
includes a second annular groove 50 b therein proximate to the
aperture 40 having a similar profile to the first annular groove 50
a. The snap ring 52 of the sleeve is receivable in either the first
ore second annular groove 50 a or 50 b such that the sleeve is held
in either an open position as illustrated in FIG. 5 or a closed
position as illustrated in FIG. 4. The sliding sleeve 44 also
includes annular wiper seals 54 which will be described more fully
below proximate to either end thereof to maintain a fluid tight
seal between the sliding sleeve and the interior of the central
portion 42.
[0040] The port bodies 38 are slidably received within the valve
body 24 so as to be radially extendable therefrom. As illustrated
in FIG. 3, the port bodies are located in their retracted position
such that an exterior surface 60 of the port bodies is aligned with
an exterior surface 62 of the raised sections 36. Each raised
section may also include limit plates 64 located to each side of
the port bodies 38 which overlap a portion of and retain pistons
within the cylinders as are more fully described below.
[0041] Each raised section 36 includes at least one void region or
cylinder 66 disposed radially therein. Each cylinder 66 includes a
piston 68 therein which is operably connected to a corresponding
port body 38 forming an actuator for selectably moving the port
bodies 38. Turning now to FIGS. 4 and 5, detailed views of one port
body 38 are illustrated at a retracted and extended position,
respectively. Each port body 38 may have an opposed pair of pistons
68 associated therewith arranged to opposed longitudinal sides of
the valve body 24. It will be appreciated that other quantities of
pistons 68 may also be utilized for each port body 38 as well. The
pistons 68 are connected to the valve body by a top plate 70 having
an exterior surface 72. The exterior surface 72 is positioned to
correspond to the exterior surface 62 of the raised sections 36 so
as to present a substantially continuous surface therewith when the
port bodies 38 are in their retracted positions. The exterior
surface 72 also includes angled end portions 74 so as to provide a
ramp or inclined surface at each end of the port body 38 when the
port bodies 38 are in an extended position. This will assist in
enabling the valve body to be longitudinally displaced within a
wellbore 10 with the vertical section 12 under thermal expansion of
the production string and thereby to minimize any shear stresses on
the port body 38.
[0042] The pistons 68 are radially moveable within the cylinders
relative to a central axis of the valve body so as to be radially
extendable therefrom. In the extended position illustrated in FIG.
5, the exterior surface 72 of the port bodies are adapted to be in
contact with the wellbore 10 so as to extend the port body 38 and
thereby enable the wellbore 10 to be placed in fluidic
communication with the central portion 42 of the valve body 24. The
pistons 68 may have a travel distance between their retracted
positions and their extended positions of between 0.10 and 0.50
inches although it will be appreciated that other distances may
also be possible. In the extended position, it will be possible to
frac that location without having to also fracture the concrete
which will be located between the valve body 24 and the wellbore
wall thereby reducing the required frac pressure. Additionally,
more than one port body 38 may be utilized and radially arranged
around the valve body so as to centre the valve body within the
wellbore when the port bodies are extended therefrom.
[0043] The pistons 68 may include seals 76 therearound so as to
seal the piston within the cylinders 66. Additionally, the port
body 38 may include a port sleeve 78 extending radially inward
through a corresponding port bore 81 within the valve body. A seal
80 may be located between the port sleeve 78 and the port bore 81
so as to provide a fluid tight seal therebetween. A snap ring 82
may be provided within the port bore 81 adapted to bear radially
inwardly upon the port sleeve 78. In the extended position, the
snap ring 82 compresses radially inwardly to provide a shoulder
upon which the port sleeve 78 may rest so as to prevent retraction
of the port body 38 as illustrated in FIG. 5. The pistons 68 may be
displaceable within the cylinders 66 by the introduction of a
pressurized fluid into a bottom portion thereof. It will also be
appreciated that other sleeve valves may be utilized which do not
include extendable pistons as illustrated herein as are commonly
known in the art.
[0044] With reference to FIG. 3, the entrance bore 94 intersect the
central passage 32 of the valve body 24. As illustrated each
entrance bore 94 may be covered by a knock-out plug 102 so as to
seal the entrance bore until removed. In operation, as concrete is
pumped down the bottom section 16, it will be followed by a plug so
as to provide an end to the volume of concrete. The plug is
pressurized by a pumping fluid (such as water, by way of
non-limiting example) so as to force the concrete down the
production string and thereafter to be extruded into the annulus
between the horizontal section and the wellbore. The knock-out
plugs 102 are designed so as to be removed or knocked-out of the
entrance bore by the concrete plug passing thereby. In such a way,
once the concrete has passed the valve body 24, the concrete plug
removes the knock-out plugs 102 so as to pressurize the entrance
bore 94 and fluid bore 90 and thereafter to extend the pistons 68
from the valve body 24 once the pressurizing fluid has reached a
sufficient pressure.
[0045] Turning now to FIG. 6, a shifting tool 200 is illustrated
within the central passage 32 of the valve body 24. The shifting
tool 200 is adapted to engage the sliding sleeve 44 and shift it
between a closed position as illustrated in FIG. 4 and an open
position in which the apertures 40 are uncovered by the sliding
sleeve 44 so as to permit fluid flow between and interior and an
exterior of the valve body 24 as illustrated in FIG. 5. The
shifting tool 200 comprises a substantially cylindrical elongate
tubular body 202 extending between first and second ends 204 and
206, respectively. The shifting tool 200 includes a central bore
210 therethrough (shown in FIGS. 7 through 9) to receive an
actuator or to permit the passage of fluids and other tools
therethrough. The shifting tool 200 includes at least one sleeve
engaging member 208 radially extendable from the tubular body 202
so as to be selectably engageable with the sliding sleeve 44 of the
valve body 24. As illustrated in the accompanying figures, three
sleeve engaging members 208 are illustrated although it will be
appreciated that other quantities may be useful as well.
[0046] The sleeve engaging members 208 comprise elongate members
extending substantially parallel to a central axis 209 of the
shifting tool between first and second ends 212 and 214,
respectively. The first and second ends 212 and 214 include first
and second catches 216 and 218, respectively for surrounding the
sliding sleeve and engaging a corresponding first or second end 43
or 45, respectively of the sliding sleeve 44 depending upon which
direction the shifting tool 200 is displaced within the valve body
24. As illustrated in FIGS. 8 and 9, the first and second catches
216 and 218 of the sleeve engaging member 208 each include and
inclined surface 220 and 222, respectively facing in opposed
directions from each other. The inclined surfaces 220 and 222 are
adapted to engage upon either the first or second annular shoulder
46 or 48 of the valve body as the shifting tool 200 is pulled or
pushed there into. The first or second annular shoulders 46 or 48
press the first or second inclined surface 220 or 222 radially
inwardly so as to press the sleeve engaging members 208 inwardly
and thereby to disengage the sleeve engaging members 208 from the
sliding sleeve 44 when the sliding sleeve 44 has been shifted to a
desired position proximate to one of the annular shoulders. In an
optional embodiment, one or both of the catches 216 or 218 may have
an extended length as illustrated in FIG. 10 such that the sleeve
engaging members are disengaged from the sliding sleeve at a
position spaced apart from one of the first or second annular
shoulders 46 or 48 and thereby adapted to position the sliding
sleeve at a third or central position within the valve body 24.
[0047] Turning to FIG. 7, the sleeve engaging members are
maintained parallel to the tubular body 202 of the shifting tool
200 by a parallel shaft 230. Each parallel shaft 230 is linked to a
sleeve engaging member 208 by a pair of spaced apart linking arms
232. The parallel shaft 230 is rotatably supported within the
shifting tool tubular body 202 by bearings or the like. The linking
arms 232 are fixedly attached to the parallel shaft 230 at a
proximate end and are received within a blind bore 234 of the
sleeve engaging members 208. As illustrated in FIG. 6, the linking
arms 232 are longitudinally spaced apart from each other along the
parallel shaft 230 and the sleeve engaging member 208 so as to be
proximate to the first and second ends 212 and 214 of the sleeve
engaging member 208.
[0048] Turning now to FIG. 8, the tubular body 202 of the shifting
tool includes a shifting bore 226 therein at a location
corresponding to each sleeve engaging member. The shifting bore 226
extends from a cavity receiving the sleeve engaging member to the
central bore 210 of the shifting tool 200. Each sleeve engaging
member 208 includes a piston 224 extending radially therefrom which
is received within the shifting bore 226. In operation, a fluid
pressure applied to the central bore 210 of the shifting tool will
be applied to the piston 224 so as to extend the piston within the
shifting bore 226 and thereby to extend the sleeve engaging members
208 from a first or retracted position within the shifting tool
tubular body 202 as illustrated in FIG. 8 to a second or extended
position for engagement on the sliding sleeve 44 as discussed above
as illustrated in FIG. 9. The parallel shafts also include helical
springs (not shown) thereon to bias the sleeve engaging members to
the retracted position.
[0049] The first end 204 of the shifting tool 200 includes an
internal threading 236 therein for connection to the external
threading of the end of a production string or pipe (not shown).
The second end 206 of the shifting tool 200 includes external
threading 238 for connection to internal threading of a downstream
productions string or further tools, such as by way of non-limiting
example a control valve as will be discussed below. An end cap 240
may be located over the external threading 238 when such a
downstream connection is not utilized.
[0050] With reference to FIGS. 8 and 9, a first control valve 300
according to a first embodiment located within a shifting tool 200
for use in wells having low hydrocarbon production flow rates. The
low flow control valve 300 comprises a valve housing 302 having a
valve passage 304 therethrough and seals 344 therearound for
sealing the valve housing 302 within the shifting tool 200. The low
flow control valve 300 includes a central housing extension 306
extending axially within the valve passage 304 and a spring housing
portion 320 downstream of the central portion 310. The central
housing extension 306 includes an end cap 308 separating an
entrance end of the valve passage from a central portion 310 of the
valve passage and an inlet bore 322 permitting a fluid to enter the
central portion 310 from the valve passage 304.
[0051] The central portion 310 of the valve passage contains a
valve piston rod 312 slidably located therein. The valve piston rod
312 includes leading and trailing pistons, 314 and 316,
respectively thereon in sealed sliding contact with the central
portion 310 of the valve passage. The leading piston 314 forms a
first chamber 313 with the end cap 308 having an inlet port 315
extending through the leading piston 314. The valve piston rod 312
also includes a leading extension 318 having an end surface 321
extending from an upstream end thereof and extending through the
end cap 308. The valve piston rod 312 is slidable within the
central portion 310 between a closed position as illustrated in
FIG. 8 and an open position as illustrated in FIG. 9. In the closed
position, the second or trailing piston 316 is sealable against the
end of the central portion 310 to close or seal the end of the
central passage and thereby prevent the flow of a fluid through the
control valve. In the open position as illustrated in FIG. 9, the
trailing piston 316 is disengagable from the end of the central
portion 310 so as to provide a path of flow, generally indicated at
319, therethrough from the central passage to the spring
housing.
[0052] A spring 324 is located within the spring housing 320 and
extends from the valve piston rod 312 to an orifice plate 326 at a
downstream end of the spring housing 320. The spring 324 biases the
valve piston rod 312 towards the closed position as illustrated in
FIG. 8. Shims or the like may be provided between the spring 324
and the orifice plate 326 so as to adjust the force exerted by the
spring upon the valve piston rod 312. In other embodiments, the
orifice plate may be axially moveable within the valve body by
threading or the like to adjust the force exerted by the spring. In
operation, fluid pumped down the production string to the valve
passage 304 passes through the inlet bore and into the central
portion 310. The pressure of the fluid within the central portion
310 is balanced upon the opposed faces of leading and trailing
pistons 314 and 316 such that the net pressure exerted upon the
valve piston rod 312 is provided by the pressure exerted on the end
surface 321 of the leading extension 318 and on the leading piston
314 from within the first chamber 313. The resulting force exerted
upon the end surface 321 is resisted by the biasing force provided
by the spring 324 as described above.
[0053] Additionally, the orifice plate 326 includes an orifice 328
therethrough selected to provide a pressure differential
thereacross under a desired fluid flow rate. In this way, when the
fluid is flowing through the central portion 310 and the spring
housing 320, the spring housing 320 will have a pressure developed
therein due to the orifice plate. This pressure developed within
the spring housing 320 will be transmitted through apertures 330
within the spring housing to a sealed region 332 around the spring
housing proximate to the shifting bore 226 of the shifting tool
200. This pressure serves to extend the pistons 224 within the
shifting bores 226 and thereby to extend the sleeve engaging
members 208 from the shifting tool. The pressure developed within
the spring housing 320 also resists the opening of the valve piston
rod 312 such that in order for the valve to open and remain open,
the pressure applied to the entrance of the valve passage 304 is
required to overcome both the biasing force of the spring 324 and
the pressure created within the spring housing 320 by the orifice
328.
[0054] The valve 300 may be closed by reducing the pressure of the
supplied fluid to below the pressure required to overcome the
spring 324 and the pressured created by the orifice 328 such that
the spring is permitted to close the valve 300 by returning the
valve piston rod 312 to the closed position as illustrate in 11 as
well as permitting the springs on the parallel shaft 230 to retract
the sleeve engaging members 208 as the pressure within the spring
housing 320 is reduced. Seals 336 as further described below may
also be utilized to seal the contact between the spring housing 320
and the interior of the central bore 210 of the shifting tool
200.
[0055] A shear sleeve 340 may be secured to the outer surface of
the valve housing 302 by shear screws 342 or the like. The sheer
sleeve 340 is sized and selected to be retained between a pipe
threaded into the internal threading 236 of the shifting tool 200
and the remainder of the shifting tool body. In such a way, should
the valve be required to be retrieved, a spherical object 334, such
as a steel ball, such as are commonly known in the art may be
dropped down the production string so as to obstruct the valve
passage 304 of the valve 300. Obstructing the flow of a fluid
through the valve passage 304 will cause a pressure to develop
above the valve so as to shear the shear screws 342 and force the
valve through the shifting tool. The strength of the sheer screws
342 may be selected so as to prevent their being sheered during
normal operation of the valve 300 such as for pressures of between
1000 and 3000 psi inlet fluid pressure. The valve illustrated in
FIGS. 8 and 9 is adapted for use in a low hydrocarbon flow rate
well. In such well types, the flow of fluids such as hydrocarbons
or other fluids is low enough that the fluid pumped down the well
to pressurize the central portion 310 is sufficient to overcome the
flow of the fluids up the well so as to pass through the orifice
328. It will be appreciated that for wells of higher well pressure
or flow rates, such a valve will be limited in its application.
[0056] In some embodiments, a cased-hole is provided with a
production tubing (or casing) fitted with sliding reclosable
sleeves as set out above at the desired location and quantity. As
illustrated in FIGS. 11 through 14, after the completion (desired
amount of sleeves and casing) is installed into the well, the well
would be set up for fracture/stimulation operations. Using, for
example, a coil tubing or stick pipe an actuation device would be
conveyed into the well and positioned within a first sleeve 23a as
illustrated in FIG. 11.
[0057] The actuation device, indifferently mentioned here as
shifting tool, such as illustrated herein and described above by
way of non-limiting example, as apparent from FIG. 11, a tool that
is equipped with a sleeve engaging member selectably extendable
from the shifting tool in parallel to a central axis of the
shifting tool and engagable upon the sleeve wherein the shifting
tool is moveable so as to cause the sleeve to selectably cover and
uncover the apertures. A suitable combination sliding sleeve and
shifting tool may be found in US2012/0125627 incorporated herein by
reference in its entirety. As illustrated in FIG. 12, the shifting
tool 200 may be engaged upon the first sleeve 44 and thereafter
shifted to uncover the apertures 40a or ports through the first
valve 23a. Thereafter a fracing operation may be performed
therethrough. After the fracturing operation is complete, the tool
200 may be utilized to shift the first sleeve 44a back to the
closed position and thereafter disengaged therefrom as set out
above. As illustrated in FIG. 13, the shifting tool 200 may then be
positioned to subsequent valves 23b and 23c to perform similar
operations thereon.
[0058] Fracturing operations would then start at any location in
the well; for example from toe-to-heel, or from heel-to-toe or at
any preferred location by opening the sleeve corresponding to the
chosen zone to be fracture; then, the fluid pressure would be
increased until reaching the fracturing pressure of the formation.
The created fracture may then be propped with the fracturing fluid
and when the operator decides to move to another zone, the
activation device will then be used to reclose the opened sleeve,
thus isolating the treated zone.
[0059] Accordingly, each zone may be fractured independently and
then isolated after the fracture is complete. The reclosing sleeve
enables to fracture and isolate each specific zone without using
any isolation (or sealing) elements such as packer, isolation plug,
or cups. This would make the pin-point fracturing technique much
more efficient and reliable than the current one involving setting
and unsetting a packer for each zone. Questions about reliability
of sealing element will be avoided and one of the many further
advantages is that it would also not require having a toe valve or
opening to run in equipment. The sleeve is reclosed after
fracture/stimulation to provide pressure integrity back to the
casing string. This opens up the opportunity to fracture/stimulate
the wellbore in any fashion. A further advantage would be that the
length of the tool string could be reduced; this would not only
allow easier handling but also reduce the torque and drag forces
and may even enable penetrating wells having high inclination
angles. Then, by removing the sealing element, there will no longer
needs to be a washing step for cleaning said sealing elements thus
reducing fluid consumption, suppressing overflush which will
contribute to better fracturing jobs.
[0060] In embodiment, the actuation device is mounted on a coiled
tubing element. The coiled tubing may remain in the wellbore during
the fracture/stimulation. Once all the zones are
fractured/stimulated the coil tubing may be lowered to the toe of
the well. During this time, a clean out of the well can be
performed without having to change any part of the Bottom Hole
Assembly (BHA) to ensure all debris and sand are washed from the
wellbore.
[0061] Once the cleanout is completed as illustrated in FIG. 14,
the shifting tool 200 is located at a bottom of the well, by way of
non-limiting example and, the actuation device is put is opening
position and the coil tubing is pulled out of the well in a
direction generally indicated at 400. The upward motion would open
all the sleeves coming out of the well leaving the well clean and
ready for production.
[0062] While the present disclosure has been disclosed with respect
to a limited number of embodiments, those skilled in the art,
having the benefit of this disclosure, will appreciate numerous
modifications and variations there from. It is intended that the
appended claims cover such modifications and variations as fall
within the true spirit and scope of the disclosure.
* * * * *