U.S. patent application number 12/501203 was filed with the patent office on 2011-01-13 for fracturing system and method.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. Invention is credited to Yang Xu.
Application Number | 20110005759 12/501203 |
Document ID | / |
Family ID | 43426618 |
Filed Date | 2011-01-13 |
United States Patent
Application |
20110005759 |
Kind Code |
A1 |
Xu; Yang |
January 13, 2011 |
FRACTURING SYSTEM AND METHOD
Abstract
A telescoping unit for a downhole tool including an innermost
portion of the telescoping unit; a block defining a restriction
disposed within the innermost portion of the telescoping unit; and
an erodable coating on the block to segregate the block from
downhole fluids and method.
Inventors: |
Xu; Yang; (Houston,
TX) |
Correspondence
Address: |
CANTOR COLBURN LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
43426618 |
Appl. No.: |
12/501203 |
Filed: |
July 10, 2009 |
Current U.S.
Class: |
166/308.1 ;
166/317 |
Current CPC
Class: |
E21B 43/114 20130101;
E21B 43/112 20130101; E21B 43/26 20130101 |
Class at
Publication: |
166/308.1 ;
166/317 |
International
Class: |
E21B 43/26 20060101
E21B043/26; E21B 34/06 20060101 E21B034/06; E21B 43/267 20060101
E21B043/267 |
Claims
1. A telescoping unit for a downhole tool comprising: an innermost
portion of the telescoping unit; a block defining a restriction
disposed within the innermost portion of the telescoping unit; and
an erodable coating on the block to segregate the block from
downhole fluids.
2. A telescoping unit as claimed in claim 1 wherein the block
comprises a dissolvable material.
3. A telescoping unit as claimed in claim 2 wherein the dissolvable
material is responsive to downhole fluids.
4. A telescoping unit as claimed in claim 1 wherein the coating is
resistant to dissolution by downhole fluids.
5. A telescoping unit as claimed in claim 1 wherein the coating is
chemically impervious to downhole fluids.
6. A telescoping unit as claimed in claim 2 wherein the dissolvable
material is at least in part an aluminum alloy.
7. A telescoping unit as claimed in claim 2 wherein the dissolvable
material is at least in part a magnesium alloy.
8. A telescoping unit as claimed in claim 1 wherein the coating is
erodable by fluid flow.
9. A telescoping unit as claimed in claim 1 wherein the coating is
erodable by proppant in a proppant laden fluid flowing
therethrough.
10. A telescoping unit for a downhole tool comprising: an innermost
portion of the telescoping unit; and a block defining a restriction
disposed within the innermost portion of the telescoping unit, the
block being resistant to dissolution and susceptible to rapid
erosion by flowing proppant to remove the block from the
telescoping unit substantially entirely within minutes of a start
of proppant fluid flowing therethrough.
11. A fracturing system comprising: at least a portion of a tubing
string; one or more telescoping units in the at least a portion of
a tubing string; one or more barriers in operable communication
with the one or more telescoping units; and a restriction disposed
in an inside dimension of the one or more telescoping units.
12. A fracturing system as claimed in claim 11 wherein the
restriction is defined by a block disposed within the innermost
portion of the one or more telescoping units.
13. A fracturing system as claimed in claim 12 wherein the block is
formed at least in part of a dissolvable material.
14. A fracturing system as claimed in claim 12 wherein the block
includes a coating that is resistant to chemical effects of
downhole fluids.
15. A fracturing system as claimed in claim 14 wherein the coating
is erodable.
16. A fracturing system as claimed in claim 14 wherein the coating
is erodable by flowing fluid.
17. A fracturing system as claimed in claim 14 wherein the coating
is erodable by proppant entrained in a flowing proppant laden
fluid.
18. A method for fracturing a formation adjacent a borehole
comprising: shifting one or more barriers to expose to tubing fluid
one or more telescoping units disposed within a tubing string;
pressuring up on the tubing string to deploy the one or more
exposed telescoping units; pressuring further to fracture the
formation in the vicinity of the one or more exposed telescoping
units; flowing a fluid from the tubing through the one or more
exposed telescoping units into the formation; eroding a coating
covering a block defining a restriction in the one or more exposed
telescoping units; and dissolving the block with downhole fluids to
which it is exposed pursuant to the eroding of the coating.
19. A method as claimed in claim 18 wherein the eroding is by
flowing fluid.
20. A method as claimed in claim 19 wherein the fluid is proppant
laden.
21. A method for fracturing a formation adjacent a borehole
comprising: shifting one or more barriers to expose to tubing fluid
one or more telescoping units disposed within a tubing string;
pressuring up on the tubing string to deploy the one or more
exposed telescoping units; pressuring further to fracture the
formation in the vicinity of the one or more exposed telescoping
units; flowing a fluid from the tubing through the one or more
exposed telescoping units into the formation; and eroding a block
defining a restriction thereby removing the block from the one or
more exposed telescoping units.
Description
BACKGROUND
[0001] In the downhole drilling and completion industry, downhole
fracturing processes generally include openings in a tubing string
in a borehole in which the tubing string is deployed. Pressure is
applied to the tubing string, for example, from a surface location.
The pressure applied to the inside of the tubing string is allowed
to propagate to outside of the tubing string through the openings
noted. The pressure is contained in zones using seals between the
tubing string and the formation so that the applied pressure has
nowhere to go but into the formation. This results in fractures in
the formation and a rush of fluid into the fracture point. Proppant
entrained in the fluid will keep the fracture open when the
pressure is relieved. While the method works well and is used
widely in the art, the fracture will generally occur at the weakest
point of the interval being fractured so that there is little
specificity or distribution of fractures. The inventor hereof
believes that greater control of the location and distribution of
fracturing would be well received by the art.
SUMMARY
[0002] A telescoping unit for a downhole tool including an
innermost portion of the telescoping unit; a block defining a
restriction disposed within the innermost portion of the
telescoping unit; and an erodable coating on the block to segregate
the block from downhole fluids.
[0003] A telescoping unit for a downhole tool including an
innermost portion of the telescoping unit; and a block defining a
restriction disposed within the innermost portion of the
telescoping unit, the block being resistant to dissolution and
susceptible to rapid erosion by flowing proppant to remove the
block from the telescoping unit substantially entirely within
minutes of a start of proppant fluid flowing therethrough.
[0004] A fracturing system including at least a portion of a tubing
string; one or more telescoping units in the at least a portion of
a tubing string; one or more barriers in operable communication
with the one or more telescoping units; and a restriction disposed
in an inside dimension of the one or more telescoping units.
[0005] A method for fracturing a formation adjacent a borehole
including shifting one or more barriers to expose to tubing fluid
one or more telescoping units disposed within a tubing string;
pressuring up on the tubing string to deploy the one or more
exposed telescoping units; pressuring further to fracture the
formation in the vicinity of the one or more exposed telescoping
units; flowing a fluid from the tubing through the one or more
exposed telescoping units into the formation; eroding a coating
covering a block defining a restriction in the one or more exposed
telescoping units; and dissolving the block with downhole fluids to
which it is exposed pursuant to the eroding of the coating.
[0006] A method for fracturing a formation adjacent a borehole
including shifting one or more barriers to expose to tubing fluid
one or more telescoping units disposed within a tubing string;
pressuring up on the tubing string to deploy the one or more
exposed telescoping units; pressuring further to fracture the
formation in the vicinity of the one or more exposed telescoping
units; flowing a fluid from the tubing through the one or more
exposed telescoping units into the formation; and eroding a block
defining a restriction thereby removing the block from the one or
more exposed telescoping units.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Referring now to the drawings wherein like elements are
numbered alike in the Figures:
[0008] FIG. 1 is a schematic view of a telescopic fracturing tool
as described herein in a pre-deployment position;
[0009] FIG. 2 is a schematic view of the tool depicted in FIG. 1
but in the deployed position;
[0010] FIG. 3 is an enlarged view of the circumscribed area 3-3 in
FIG. 2; and
[0011] FIG. 4 is another embodiment depicted, as is FIG. 3.
DETAILED DESCRIPTION
[0012] Referring to FIG. 1, a fracturing system 10 is illustrated.
It is to be understood that the illustrated configuration can be
duplicated along a tubing string 12 to provide for as many
telescoping unit(s) 14 as is/are required or desired in any
particular system. The telescoping unit(s) 14 are disposed within
the string 12 using an attachment 13 such as threads, a press fit,
welding, etc. Each of the telescoping units 14 is initially closed
from the environment inside of the tubing string by a barrier 16
such as for example a sliding sleeve. This ensures that there is no
pressure differential across the unit(s) 14 during the run in phase
of tool use.
[0013] The barrier, in one embodiment, is configured with seals 18
both uphole and downhole of the telescoping unit(s) 14 to ensure
that the barrier and not the unit(s) 14 bear any differential
pressure, which prevents fluid flow thereacross, and that any
fluidic factors present inside of tubing string 12 are not
transmitted to the telescoping unit(s) 14. One or more of the
barriers 16 may be moved to expose the telescopic unit(s) 14 when
the time to fracture the formation has arrived. This may be
accomplished using a shifting tool or a droppable plug, etc. In one
embodiment, different size drop plugs, counting plugs (such as
those described in U.S. application Ser. No. 12/437,412 filed May
7, 2009, U.S. application Ser. No. 12/470,927 filed May 22, 2009
and U.S. application Ser. No. 12/470,931 filed on May 22, 2009,
could be employed.
[0014] To render a telescoping unit 14 effective for fluid flow,
the inside diameter must be of a sufficient size D to accommodate a
sufficient amount of flow. Commonly, the size is about 0.375 inch
to about 1 inch in diameter. This size does not promote a
sufficient pressure drop thereacross to allow for effective
deployment of the unit(s) 14 based upon tubing pressure. In order
to remedy this, and as will be best understood by viewing FIGS. 3
and 4, telescoping unit(s) 14 are configured with a restriction 20
provided by a block 22 at an innermost telescopic portion 24 of the
telescoping unit 14. The restriction promotes a sufficient pressure
drop across the unit(s) 14 that they will completely radially
deploy. While the illustration of FIG. 3 is of a nozzle
configuration, it is equally effective to configure the restriction
in a tubular form such as that shown in FIG. 4. The geometry of the
restriction 20 is unimportant.
[0015] The astute reader will question the earlier statement herein
that a sufficient inside diameter of the unit(s) 14 is needed but
then that a restriction 20 is placed within this dimension D.
Referring more closely to FIGS. 3 and 4, it will be appreciated
that the block 22 defining restriction 20 comprises a structure
that has a base material 30 for structural integrity sufficient to
withstand the pressure differential created thereby and a coating
32 to protect the base material. In one embodiment the base
material 30 comprises a water based or other downhole fluid soluble
material such as aluminum or magnesium alloy, one possibility being
the commercially available "dissolvable" alloy from TAFA
Incorporated, Concord, N.H. The coating 32 comprises a water and
downhole fluid impervious (or at least dissolution resistant)
material such as Teflon, polyurethane, rubber, metal coatings such
as aluminum, copper, etc. The coating 32 is applied to the soluble
material 30 by any known and suitable process for the particular
coating selected. In an alternate embodiment, the base material and
coating can comprise all erodable material and not require
dissolution at all. In such event there could be layers of material
if desired or the block 22 can be made of one layer of erodable
material. Materials include polyurethane, copper and other
materials exhibiting properties of strength sufficient to withstand
the anticipated pressure differential in use without fracturing and
at the same time being easily erodable such that complete removal
through erosion pursuant to proppant flow therethrough will occur
within seconds to minutes after flow commences.
[0016] In the first embodiment discussed, the construction as
stated provides significant advantage in that the coating 32 will
resist the downhole fluid chemically but is erosively susceptible.
Because of this, as proppant flow begins after fracturing of the
formation through the unit(s) 14, the coating is quickly eroded
away thereby exposing the soluble material base 30 to the downhole
fluids, to which it is chemically susceptible. The base material 30
will then quickly be dissolved and thereby removed from the units
14. At this point the innermost portion 24 of the unit(s) 14 is at
dimension D. In the second embodiment discussed, the entire block
is eroded resulting similarly in the innermost portion 24 of the
unit(s) 14 being at dimension D.
[0017] In operation, once a selected number (one or more) of the
telescoping units 14 is/are exposed to tubing pressure by removing
the barrier(s) 16, the pressure in the tubing is raised from the
surface. The fluid pressure acts to deploy the unit(s) 14, taking
advantage of the pressure differential occasioned by the
restriction 20 in each "unbarriered" unit 14. Since fluid is not
actually flowing to any appreciable extent at this point, the
coating 32 (or Block 22) is not eroded. Rather, the pressure
differential simply deploys the unit(s) 14 into proximity or
contact with a formation wall. Pressure is raised higher until
fracturing occurs in the formation. At this point the fluid in the
tubing begins to flow into the formation carrying proppant with it
to maintain the fractures open. As the proppant filled fluid or
even fluid that does not contain proppant moves through the
restriction 20, it erodes the coating 32 (or simply the whole block
22) thereby exposing the base material 30 to fluids within which it
is soluble. It will be noted that erosion may be faster in the
embodiment of FIG. 3 than in the embodiment of FIG. 4 because the
nozzle-type cross-section of FIG. 3 will increase velocity of fluid
flowing therethrough, the velocity of flowing proppant particles
being directly related to impact force of the particles with the
coating, which of course is directly related to speed of erosion.
In either of the illustrated embodiments or other similar
embodiments, erosion of the coating layer occurs within a very
short time frame such as a few seconds to a few minutes of the
proppant or nonproppant fluid moving into the formation. Once this
occurs, either block is erosively removed or the protection offered
the soluble base material 30 by the coating 32 is breached and the
base material will quickly dissolve, again on the order of several
seconds to several minutes.
[0018] Finally it is to be understood while one or more embodiments
have been shown and described, modifications and substitutions may
be made thereto without departing from the spirit and scope of the
invention. Accordingly, it is to be understood that the present
invention has been described by way of illustrations and not
limitation.
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