U.S. patent application number 15/051431 was filed with the patent office on 2016-09-01 for methods of modifying formation properties.
The applicant listed for this patent is Schlumberger Technology Corporation. Invention is credited to Cengiz Esmersoy, Andrew Mark Hawthorn.
Application Number | 20160251947 15/051431 |
Document ID | / |
Family ID | 56798189 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160251947 |
Kind Code |
A1 |
Hawthorn; Andrew Mark ; et
al. |
September 1, 2016 |
Methods of Modifying Formation Properties
Abstract
A method for modifying formation properties is disclosed. The
method may include drilling a first wellbore into a first geologic
layer. The first geologic layer may be in proximity to a second
geologic layer. The method may also include removing material from
the first geologic layer using a first material removal process.
The properties of the first geologic layer may be changed and the
properties of the second geologic layer may be changed.
Inventors: |
Hawthorn; Andrew Mark;
(Missouri City, TX) ; Esmersoy; Cengiz; (Sugar
Land, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Family ID: |
56798189 |
Appl. No.: |
15/051431 |
Filed: |
February 23, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62121911 |
Feb 27, 2015 |
|
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Current U.S.
Class: |
166/307 |
Current CPC
Class: |
E21B 43/00 20130101 |
International
Class: |
E21B 43/16 20060101
E21B043/16; E21B 43/285 20060101 E21B043/285; E21B 43/26 20060101
E21B043/26 |
Claims
1. A method for modifying formation properties, comprising:
drilling a first wellbore into a first geologic layer in proximity
to a second geologic layer; removing material from the first
geologic layer using a first material removal process; changing
properties of the first geologic layer; and changing properties of
the second geologic layer.
2. The method for modifying formation properties of claim 1,
wherein the first geologic layer includes a salt formation and the
first material removal process includes solution mining the salt
formation.
3. The method for modifying formation properties of claim 1,
wherein the changing of the properties of the first geologic layer
induces the changing of the properties of the second geologic
layer.
4. The method for modifying formation properties of claim 1,
further comprising: drilling a second wellbore into the first
geologic layer; and removing material from the first geologic layer
using a second material removal process.
5. The method for modifying formation properties of claim 4,
wherein the first material removal process is the same as the
second material removal process.
6. The method for modifying formation properties of claim 1,
wherein the first material removal process includes acidizing the
first geologic layer.
7. The method for modifying formation properties of claim, 1
further comprising: pressurizing the first geologic layer after
removing the material from the first geologic layer using the first
material removal process.
8. The method for modifying formation properties of claim 1,
wherein changing the properties of the second geologic layer
includes inducing fractures within the second geologic layer.
9. The method for modifying formation properties of claim 1,
further comprising: hydraulically fracturing the second geologic
layer.
10. The method for modifying formation properties of claim 9,
wherein the hydraulic fracturing of the second geologic layer
occurs after the changing the properties of the second geologic
layer.
11. A method for modifying formation properties, comprising:
drilling a wellbore into a mineral layer in proximity to a
hydrocarbon reservoir; removing material from the mineral layer
using a material removal process; changing properties of the
mineral layer; and changing properties of the hydrocarbon
reservoir.
12. The method for modifying formation properties of claim 11,
wherein the mineral layer includes a salt formation and the
material removal process includes solution mining the salt
formation.
13. The method for modifying formation properties of claim 11,
wherein the changing of the properties of the mineral layer
includes inducing the changing of the properties of the hydrocarbon
reservoir.
14. The method for modifying formation properties of claim 13,
wherein the changing of the properties of the hydrocarbon reservoir
increases completion quality of the hydrocarbon reservoir.
15. The method for modifying formation properties of claim 14,
further comprising extracting hydrocarbons from the hydrocarbon
reservoir.
16. The method for modifying formation properties of claim 11,
wherein changing the properties of the hydrocarbon reservoir
includes inducing fractures within the hydrocarbon reservoir and
increasing permeability of the hydrocarbon reservoir.
17. The method for modifying formation properties of claim 15,
wherein removing material from the mineral layer using a material
removal process occurs while extracting hydrocarbons from the
hydrocarbon reservoir.
18. The method for modifying formation properties of claim 15,
wherein changing the properties of the hydrocarbon reservoir occurs
while extracting hydrocarbons from the hydrocarbon reservoir.
19. The method for modifying formation properties of claim 11,
wherein the mineral layer is located below the hydrocarbon
reservoir.
20. The method for modifying formation properties of claim 11,
wherein the mineral layer includes a carbonate formation and the
material removal process includes acidizing the carbonate
formation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 62/121,911 filed on Feb. 27, 2015 entitled,
"Methods of Modifying Formation Properties," the contents of which
are incorporated herein in its entirety.
FIELD OF THE INVENTION
[0002] Some embodiments described herein generally relate to
systems, apparatuses, and methods for use in modifying the
properties of a formation.
BACKGROUND
[0003] Reservoir quality and completion quality are two aspects of
evaluating oil and gas reservoirs. Reservoir quality is a
characterization of the amount and type of hydrocarbons within a
reservoir, and completion quality is a characterization of the
prospects for extracting the hydrocarbons within a reservoir. For
example, some reservoirs may have a very high relative reservoir
quality, with a large amount of valuable hydrocarbons, while other
reservoirs may have a low relative reservoir quality because they
have very few or low value hydrocarbon content. Some reservoirs may
also have a high relative completion quality, meaning, for example,
that the hydrocarbons within the reservoir may be extracted using
conventional drilling and extraction techniques or other low cost
drilling and extraction techniques. Some reservoirs may have a low
completion quality, and unconventional mining and extraction
techniques or other relatively high cost drilling and extraction
techniques may be used to extract the hydrocarbons within the
reservoir. Some high reservoir quality, but low completion quality,
reservoirs are left untouched, because the high quality of their
hydrocarbon content does not outweigh the low completion quality
and high extraction costs of extracting the hydrocarbons using
currently available extraction techniques.
SUMMARY
[0004] This summary is provided to introduce a selection of
concepts that are further described below in the detailed
description. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used as an aid in limiting the scope of the claimed
subject matter.
[0005] In one non-limiting embodiment, a method for modifying
formation properties is disclosed. The method may include drilling
a first wellbore into a first geologic layer. The first geologic
layer may be in proximity to a second geologic layer. The method
may also include removing material from the first geologic layer
using a first material removal process. The properties of the first
geologic layer may be changed and the properties of the second
geologic layer may be changed.
[0006] In another non-limiting embodiment, a method for modifying
formation properties is disclosed. The method may include drilling
a wellbore into a mineral layer. The mineral layer may be in
proximity to a hydrocarbon reservoir. The method may also include
removing material from the mineral layer using a material removal
process. The properties of the mineral layer may be changed and the
properties of the hydrocarbon reservoir may be changed.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0007] FIG. 1 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein;
[0008] FIG. 2 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein;
[0009] FIG. 3 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein;
[0010] FIG. 4 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein;
[0011] FIG. 5 depicts a plurality of drilling rigs and wellbores in
a formation according to one or more embodiments disclosed
herein;
[0012] FIG. 6 depicts a plurality of drilling rigs and wellbores in
a formation according to one or more embodiments disclosed
herein;
[0013] FIG. 7 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein;
[0014] FIG. 8 depicts a drilling rig and wellbore in a formation
according to one or more embodiments disclosed herein; and
[0015] FIG. 9 depicts a method of modifying a formation according
to one or more embodiments disclosed herein.
DETAILED DESCRIPTION
[0016] FIG. 1 depicts an embodiment of a drilling system 100 for
aiding in the exploration of a formation 10 and the extraction of
hydrocarbons, including oil and gas, from a hydrocarbon reservoir
220. The formation 10 may include one or more geologic layers. For
example, the formation 10 includes a first geologic layer 210, the
hydrocarbon reservoir 220, a second geologic layer that may be a
shale layer 230, a mineral layer 240, and a third geologic layer
250.
[0017] The first geologic layer 210 may begin at a ground surface
12 and extend through the formation to the hydrocarbon reservoir
220 and the shale layer 230. In some embodiments, the first
geologic layer may itself include one or more additional geologic
layers. For example, the first geologic layer 210 may include one
or more porous and/or non-porous layers between the ground surface
12 and the hydrocarbon reservoir 220 and the shale layer 230. In
some embodiments, the first geologic layer 210 may include one or
more additional hydrocarbon reservoirs 220.
[0018] The formation 10 may also include the hydrocarbon reservoir
220. The hydrocarbon reservoir 220 may be located within the
formation 10 between the first geologic layer 210 and the shale
layer 230. The hydrocarbon reservoir 220 may include oil, natural
gas, or a combination of both oil and natural gas. Although
depicted as a separate layer, in some embodiments the hydrocarbon
reservoir 220 is incorporated into other geologic layers within the
formation 10. For example, the hydrocarbon reservoir 220 may be
held within a shale layer. Although depicted in FIG. 1 as having a
single hydrocarbon reservoir 220, in some embodiments the formation
10 may include more than one hydrocarbon reservoir 220.
[0019] The shale layer 230 is a geologic layer of non-porous or
semi-porous shale. In some embodiments, the shale layer 230 is
located below the hydrocarbon reservoir 220, as shown in FIG. 1,
or, in some embodiments, the shale layer 230 may be located above
the hydrocarbon reservoir 220, or the formation 10 may not have a
shale layer 230. As shown in FIG. 1, the shale layer 230 separates
the hydrocarbon reservoir 220 from the mineral layer 240.
[0020] The mineral layer 240 may be located in proximity to or near
the hydrocarbon reservoir 220. In proximity to or near the
hydrocarbon reservoir 220 means that a geologic layer, in this
embodiment, the mineral layer 240, is close enough to the
hydrocarbon reservoir 220 that changes in the properties of the
mineral layer 240 may have an effect on the properties of the
hydrocarbon reservoir 220. For example, the mineral layer 240 may
be adjacent or directly adjacent to the hydrocarbon reservoir 220,
or the mineral layer 240 may be separated from the hydrocarbon
layer 220 by hundreds or thousands of meters.
[0021] The mineral layer 240 may be below the shale layer 230 and
the hydrocarbon reservoir 220 and above the third geologic layer
250. The mineral layer 240 may include deposits of one or more
minerals and may include other deposits, such as, for example,
water. In particular, the mineral layer 240 may include one or more
of salt, limestone, dolomite, and other minerals. Although depicted
as being located below the hydrocarbon reservoir 220, in some
embodiments, the mineral layer 240 may be located above, or may
partially or completely surround, the hydrocarbon layer 220.
Although depicted as having a single mineral layer 240, in some
embodiments, the formation 10 may include more than one mineral
layer 240. In embodiments with more than one mineral layer 240, the
mineral layers 240 may be located above, below, and/or around the
hydrocarbon deposit 220.
[0022] The formation 10 may also include a third geologic layer
250. The third geologic layer 250 may begin at the mineral layer
240 and the shale layer 230 and extend through and to the bottom of
the formation 10. In some embodiments, the third geologic layer 250
may itself include one or more additional geologic layers. For
example, the third geologic layer 250 may include one or more
porous and/or non-porous layers and one or more additional
hydrocarbon reservoirs 220.
[0023] FIG. 1 also illustrates a land-based drilling system 100
positioned over a wellbore 120, and a drill string 130 for
exploring formation 10. In the illustrated embodiment, the wellbore
120 is formed by drilling. Those of ordinary skill in the art given
the benefit of this disclosure will appreciate that the subject
matter of this disclosure also finds application in rotary drilling
and directional drilling applications, and is not limited to
land-based rigs.
[0024] The drill string 120 may be rotated by a rotary table which
engages a kelly at the upper end of the drill string 130. The drill
string 130 may be suspended from a hook, and attached to a
travelling block through the kelly and a rotary swivel which
permits rotation of the drill string relative to the hook. In some
embodiments, the drill string 130 may be rotated using other
methods, such as by using a topdrive.
[0025] The drill string 130 is suspended within the wellbore 120
and includes a downehole tool 132 as part of a bottom hole assembly
at its lower, terminal, or bottom end. The downhole tool 132 may
include a drill bit. The drill string 130 can also include a
variety of other downhole tools 132, for example, reamers, logging
while drilling tools, or other drilling tools. In some embodiments,
the drill string may be a wireline tool or other tool, such as the
tool associated with acidizing minerals, removing water for the
formation 10, solution mining, or vibratory tools.
[0026] The wellbore 120 may include one or more sections. For
example the wellbore 120 depicted in FIG. 1 includes three
sections, a first or vertical section 122, a second or transition
section 124 and a third or horizontal section 126. The vertical
section 122 may be substantially vertical and is the section of the
wellbore that penetrates through the depth of the formation 10. A
conventional wellbore may have a vertical section 122 without the
transition section 124 or the horizontal section 126. An
unconventional wellbore may also include the transition section 124
and the horizontal section 126.
[0027] The transition section 124 of the wellbore 120 transitions
the wellbore from a substantially vertical section to a
substantially horizontal section. The horizontal section 126
penetrates through the mineral layer 240. Geologic layers in the
formation 10, such as the mineral layer 240, may be formed in
substantially horizontally arranged layers. By drilling a
horizontal or substantially horizontal wellbore section, the
wellbore may penetrate a greater portion of the geologic layer than
if the wellbore penetrated the layer vertically.
[0028] For example, as shown in FIG. 1, the horizontal section 126
of the wellbore 120 enables the wellbore 120 to penetrate a
majority of the cross section of the mineral layer 240. Although
depicted as penetrating a majority of the cross section of the
mineral layer 240, the horizontal section 126 of the wellbore 120
may be extended though additional horizontal drilling, such that
the wellbore 120 extends through more of the mineral layer 240, for
example, the wellbore 120 may extend through the entirety of or
substantially the entirety of the cross section of the mineral
layer 240.
[0029] Although depicted as a land-based drilling system, drilling
system 100 may be an off-shore drilling system. In an offshore
drilling system, the drilling system 100 may include a drilling
platform or ship, and the ground surface 12 may be a sea floor.
[0030] FIG. 1 also depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. The process includes assembling a drilling system
100, including erecting the drilling rig 110, and drilling a
wellbore 120 using, for example, a drill string 130. The wellbore
120 is drilled into the formation 10 to a depth near the depth of
the mineral layer 240. The wellbore 120 may be drilled to include a
transition section 124 that transitions the wellbore 120 from the
vertical section 122 of the wellbore 120 to a horizontal section
126 of the wellbore 120. The wellbore 120 may be further extended
to include the horizontal section 126 that penetrates through the
cross section of the mineral layer 240.
[0031] Other drilling and formation exploration processes may also
occur. For example, a wellbore casing may be installed in the
wellbore, the wellbore may be enlarged, for example through
reaming, formation imaging processes may take place to further
understand the properties and makeup of the formation 10, and other
processes may be performed.
[0032] FIG. 2 depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. The drill string 130 has been removed for clarity.
In some embodiments, the drill string 130 may be located within the
wellbore 120 during the portions of the process depicted in FIG. 2,
while in some embodiments, the drill string 130 may be removed from
the wellbore 120. In some embodiments, the mineral layer 240 may be
a salt deposit layer. In FIG. 2, the wellbore 120 is drilled into
the salt deposits of the mineral layer 240 and the salt may be
solution mined from the mineral layer 240. The solution mining
creates a void, represented by the void 242. Although depicted as a
singled large void, the void 242 may represent smaller voids within
the mineral layer 240 or the removal of material, such as salt,
from the mineral layer 240.
[0033] In a solution mining process, one or more wellbores are
drilled into the mineral layer 240. Some of the wellbores inject
water into the salt deposits in the mineral layer 240 to create a
salt solution or brine which can then be pumped out of the
formation through, for example, the horizontal section 126 of the
wellbore 120 as represented by the flow arrows 131. In some
embodiments the salt deposits may be mined via underground salt
mining techniques whereby the salt deposits are removed through
mechanical or mechanized equipment.
[0034] By removing the salt within the mineral layer 240, the
solution mining process may change the properties of the mineral
layer, for example the solution mining process may change the
stress regime within the mineral layer, may weaken the mineral
layer 240, or may reduce the support the mineral layer 240 may
provide to the rest of the formation 10, in particular the shale
layer 230 and the hydrocarbon reservoir 220. As discussed in more
detail below, the solution mining of the mineral layer 240 may also
change the stress regime within the hydrocarbon reservoir 220.
[0035] In some embodiments, rather than or in addition to including
salt deposits, the mineral layer 240 may be or include a layer or
layers of limestone, dolomite, or other carbonate or deposit that
can be acidized. In an acidizing process, one or more wellbores are
drilled into the mineral layer 240, for example wellbore 120. Acid
is injected into the formation 10 through the wellbore 120 and the
acid reacts with the limestone, dolomite or other material within
the mineral layer 240 of the formation 10 to clean, dissolve, and
remove the minerals within the mineral layer 240.
[0036] By removing the carbonates, such as the limestone or
dolomite within the mineral layer 240, the acidizing process may
change the properties of the mineral layer 240, for example the
acidizing process may change the stress regime within the mineral
layer 240, may weaken the mineral layer 240, or may reduce the
support the mineral layer 240 may provide to the rest of the
formation 10, in particular the shale layer 230 and the hydrocarbon
reservoir 220. As discussed in more detail below, the acidizing of
the mineral layer 240 may also change the stress regime within the
hydrocarbon reservoir 220.
[0037] In some embodiments, the mineral layer 240 of formation 10
may be or include water or other liquids. In such embodiments, the
water may be pumped out or otherwise removed from the mineral layer
240. Removing the water may change the properties of the mineral
layer 240. For example, water held within the mineral layer 240 may
provide support to the mineral layer 240. By removing the water,
the properties of the mineral layer 240 may be changed, for example
the stress regime within the mineral layer may change such that the
mineral layer 240 is weaker, or the mineral layer 240 may provide
less support to the rest of the formation 10, in particular the
mineral layer 240 may provide less support to the shale layer 230
and the hydrocarbon reservoir 220. As discussed in more detail
below, removing water from the mineral layer 240 may also change
the stress regime within the hydrocarbon reservoir 220.
[0038] In some embodiments, vibrator tools may be used within the
mineral layer 240 in addition to or alternatively to one or more of
removing water from the mineral later 240, acidizing the mineral
layer 240, and salt mining the mineral layer 240. The vibratory
tools may cause mechanical waves, such as seismic waves, to
propagate through the formation 10 and in particular within the
mineral layer 240 and/or the hydrocarbon reservoir 220. The
mechanical waves may change the stress regime within the formation
10 by, for example, causing fractures within the formation 10, or
causing one or more of the geologic layers to settle or compact and
other geologic layers to stretch or expand.
[0039] Although the processes described above are discussed in the
context of the mineral layer 240, in some embodiments, the
processes may be carried out on one or more of the portions of the
formation 10 that are not the mineral layer 240, for example, the
first geologic layer 210, the shale layer 230, or the third
geologic layer 250.
[0040] The processes described above, including salt mining,
acidizing, water removal, and vibration, collectively referred to
as removal processes, may be performed before, during, or after
removal of hydrocarbons from the hydrocarbon reservoir 220. In some
embodiments, removing oil from the hydrocarbon reservoir 220 with a
low completion quality may be expensive or very technically
difficult; therefore, a well operator may perform one or more of
the removal processes described above to change the stress regime
within the hydrocarbon reservoir 220.
[0041] In some embodiments, a well operator may have already
completed initial extraction of hydrocarbons from the hydrocarbon
reservoir 220 using conventional or unconventional oil drilling
techniques, and extracted some of the hydrocarbons within the
hydrocarbon reservoir 220. The hydrocarbon reservoir 220 may still
hold hydrocarbons within low porosity regions of the hydrocarbon
reservoir 220. The cost to extract the remaining hydrocarbons
without modifying the formation 10 using one or more of the removal
techniques described above may exceed the value of the remaining
hydrocarbons, therefore a well operator may use one or more of the
material removal processes described above to increase the
completion quality of an existing or partially depleted hydrocarbon
reservoir.
[0042] In some embodiments, a well operator may have begun
extraction of hydrocarbons from the hydrocarbon reservoir 220 using
conventional or unconventional oil drilling techniques and
extracted some of the hydrocarbons within the hydrocarbon reservoir
220 which may be producing hydrocarbons at a low rate. In such an
embodiment, a well operator may use one or more material removal
processes in the formation 10 to change the stress regime within
the formation 10, which may increase the hydrocarbon extraction
rate from the hydrocarbon reservoir 220.
[0043] FIG. 3 depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. The drill string 130 has been removed for clarity.
In some embodiments, the drill string 130 may be located within the
wellbore 120 during the portions of the process depicted in FIG. 3,
while in some embodiments, the drill string may be removed from the
wellbore 120.
[0044] In the embodiment shown in FIG. 3, one or more of the
material removal processes has been carried out on the mineral
layer 240. The one or more material removal processes has changed
the stress regime within the formation 10. In particular, in FIG. 3
the mineral layer 240 of the formation 10 has been weakened such
that it provides less support for the shale layer 230 and the
hydrocarbon reservoir 220. The weight of the shale layer 230 and
hydrocarbon reservoir 220, having less support from the mineral
layer 240, may begin to stretch and/or collapse. The force caused
by the weight of the formation 10 above the mineral layer 220 and
the movement of the shale layer 230 and the hydrocarbon reservoir
220 is represented by the arrows 232. The stretching or collapsing
of the hydrocarbon reservoir 220 may cause a change in the stress
regime within the hydrocarbon reservoir 220, and cracks, such as
cracks 222, may form within the hydrocarbon reservoir 220. The
relative movement or displacement of the hydrocarbon reservoir 220,
the shale layer 230, and the mineral layer 240 are not shown to
scale. The movement or displacement has been exaggerated for
clarity.
[0045] The cracks 222 in the hydrocarbon reservoir may increase the
porosity in the hydrocarbon reservoir 220. The increase in porosity
of the hydrocarbon reservoir 220 may cause an increase in the
permeability of the hydrocarbon reservoir 220 such that the
hydrocarbons within the hydrocarbon reservoir 220 flow from the
formation 10 and into the wellbore 120 with less resistance as
compared to the flow from the formation 10 and into the wellbore
120 before the one or more material removal processes were carried
out on the formation 10. This increase in porosity and permeability
may increase the completion quality of a hydrocarbon reservoir 220,
such as, for example, a hydrocarbon reservoir 220 with an initially
low completion quality, such that extraction using conventional or
unconventional drilling techniques without using one or more of the
above discussed material removal processes would be technically or
cost prohibitive, but may not be technically or cost prohibitive
after using one or more of the above discussed material removal
processes.
[0046] The cracks 222 in the hydrocarbon reservoir 220 may remain
open after their formation because the properties of the formation
10 and, in particular, the stress regime within the formation 10,
have been changed by the material removal processes such that the
cracks 222 do not close. For example, when the mineral layer 240
included salt that was solution mined and removed from the
formation 10, the support provided by the salt is removed and the
hydrocarbon reservoir 220 may settle. The settling may cause the
cracks 222 to form and the cracks 222 may stay open until, for
example, the mineral layer 240 is pumped back up to provide support
back to the hydrocarbon reservoir 220, or further settling and
geologic action closes the cracks 222.
[0047] The cracks 222 may not form immediately after a material
removal process begins. In some embodiments, the cracks 222 take
days, months, or years after the completion of the material removal
process has completed to form, such that the completion quality of
the hydrocarbon reservoir 220 increases. For example, in some
embodiments, after starting material removal, natural geologic
processes such as settling, stretching, and compacting of portions
of the formation may cause the cracks 222 to form. In some
embodiments, the cracks 222 may begin forming during the material
removal process such that the completion quality of the hydrocarbon
reservoir 220 increases before completion of the material removal
processes.
[0048] In some embodiments, proppants may be injected into the
hydrocarbon reservoir 220 during or after the formation of the
cracks 222 within the hydrocarbon reservoir 220. The proppants may
become lodged in the cracks 222 and may aid in keeping the cracks
open, which may maintain porosity and permeability of the
hydrocarbon reservoir 220. The proppants may be injected into the
hydrocarbon reservoir 220 though an additional wellbore, such as a
wellbore 320 in FIGS. 5 and 6, or through a secondary wellbore,
such as the secondary wellbore 140 in FIG. 6.
[0049] FIG. 4 depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. The drill string 130 has been removed for clarity.
In some embodiments, the drill string 130 may be located within the
wellbore 120 during the portions of the process depicted in FIG. 4,
while in some embodiments, the drill string may be removed from the
wellbore 120. In FIG. 4 the mineral layer 240 is pumped up, whereby
fluid and/or other material is injected from the wellbore 120 and
into the mineral layer 240, as represented by arrows 128, to
pressurize the mineral layer 240.
[0050] The injection of fluid and/or other material may cause an
increase in pressure within the mineral layer or may otherwise
cause movement or displacement of the shale layer 230 and/or the
hydrocarbon reservoir 220, as represented by the arrows 234. The
movement or displacement of the hydrocarbon reservoir 220 may
increase or lengthen the existing cracks 222 within the hydrocarbon
reservoir 220, or may cause additional cracks 222 to form.
[0051] Pumping up of the mineral layer 240 may occur before or
after the material removal processes discussed above. In some
embodiments, after one or more of the material removal processes
are conducted on the mineral layer 240, proppants may be injected
into the cracks 222 of the hydrocarbon reservoir 220 before pumping
up the mineral layer 240. The proppants may act to increase the
stress within the hydrocarbon reservoir 220 during the pumping up
process and may cause further cracking within the hydrocarbon
reservoir. After pumping up the mineral layer 240, at least some of
the liquid or other material used in the pumping up process may be
removed from the mineral layer 240. Removing the liquid or other
material may reduce the pressure within the mineral layer 240.
[0052] Multiple material removal processes and pumping up processes
may occur. For example, after a first material removal process,
such as acidizing the mineral layer 240, a well operator may pump
up the mineral layer 240, and then acidize the mineral layer 240
again. Repetition of material removal processes and/or pumping up
processes may change the stress regime in the formation 10 and, in
particular, the hydrocarbon reservoir 220, through fatigue, e.g.,
the application and removal of a load or force on the hydrocarbon
reservoir 220. As with the material removal processes, the pumping
up process may take place before, during, or after initial
extraction of hydrocarbons from the hydrocarbon reservoir 220.
[0053] FIG. 5 depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. FIG. 5 depicts a formation 10 after one or more
material removal processes and/or pumping up processes have been
carried out on the mineral layer 240, and cracks 222 have been
formed in the hydrocarbon reservoir 220. In some embodiments,
hydraulic fracturing processes may be carried out within the
hydrocarbon reservoir 220.
[0054] The embodiment for FIG. 5 includes an additional land-based
drilling system 300 includes a drilling rig 310 positioned over a
wellbore 320 and a drill string 330 for exploring formation 10. In
the illustrated embodiment, the wellbore 320 is formed by drilling.
Those of ordinary skill in the art given the benefit of this
disclosure will appreciate that the subject matter of this
disclosure also finds application in rotary drilling and
directional drilling applications, and is not limited to land-based
rigs.
[0055] The drill string 330 is suspended within the wellbore 320
and includes a bottom hole assembly 312. The bottom hole assembly
312 may include one or more tools for hydraulically fracturing the
hydraulic reservoir 220 through the wellbore 320.
[0056] The wellbore 320 may include one or more sections. For
example the wellbore 320 depicted in FIG. 5 includes three
sections, a first or vertical section, a second or transition
section and a third or horizontal section. The transition section
of the wellbore 320 transitions the wellbore from a substantially
vertical section to a substantially horizontal section. The
horizontal section penetrates through the hydrocarbon reservoir
220. By drilling a horizontal or substantially horizontal wellbore
section, the wellbore 320 may penetrate a greater portion of the
hydrocarbon reservoir 220 than if the wellbore included a single,
vertical section.
[0057] Hydraulic fracturing of the hydrocarbon reservoir 220,
indicated by the arrows 314, may further increase the porosity and
permeability of the hydrocarbon reservoir 220 by inducing
additional cracks 222 within the hydrocarbon reservoir 220. The
hydraulic fracturing process may take place before, during, or
after the material removal processes and/or the pumping up
processes discussed above.
[0058] FIG. 6 depicts portions of a process for modifying the
properties of the formation 10 and, in particular, the hydrocarbon
reservoir 220. FIG. 6 depicts a formation 10 after one or more
material removal processes and/or pumping up processes have been
carried out on the mineral layer 240, and cracks 222 have been
formed in the hydrocarbon reservoir 220. In some embodiments,
hydraulic fracturing processes may have also been carried out
within the hydrocarbon reservoir 220.
[0059] An additional land-based drilling system 400 includes a
drilling rig 410 that may be positioned over a wellbore 420 and a
drill string 430 for exploring formation 10. In the illustrated
embodiment, the wellbore 420 is formed by drilling. Those of
ordinary skill in the art given the benefit of this disclosure will
appreciate that the subject matter of this disclosure also finds
application in rotary drilling and directional drilling
applications, and is not limited to land-based rigs.
[0060] The drill string 430 is suspended within the wellbore 420
and includes a downhole tool 412. The downhole tool 412 may include
one or more tools for drilling into the formation, such as a drill
bit, or tools for extracting hydrocarbons from the hydrocarbon
reservoir 220.
[0061] Although the wellbore 420 is depicted as a conventional
wellbore including a single vertical section, in some embodiments
the wellbore 420 may be an unconventional wellbore that includes
one or more transition and horizontal sections. The wellbore 420
may be used for additional hydraulic fracturing of the hydrocarbon
reservoir, hydrocarbon extraction from the hydrocarbon reservoir,
or other drilling processes.
[0062] The wellbore 120 may include a secondary wellbore 140. The
secondary wellbore 140 may be used in addition to or in place of
one or more of the wellbore 420 and wellbore 320 for exploring the
formation 10 and/or extracting hydrocarbons from the hydrocarbon
reservoir 220. For example, rather than drilling wellbore 420 and
wellbore 320 to hydraulically fracture the hydrocarbon reservoir
220 and to extract the hydrocarbons, a well operator may use the
wellbore 120 for material removal or other processes in the mineral
layer 240 and hydraulically fracture the hydrocarbon reservoir 220
and extract the hydrocarbons therein through the secondary wellbore
140.
[0063] FIG. 7 depicts portions of a process for modifying the
properties of the formation 20 and, in particular, the hydrocarbon
reservoir 290. The formation 20 may include one or more geologic
layers. For example, the formation 20 includes a first geologic
layer 260, a hydrocarbon reservoir 290, a second geologic layer
that may be a shale layer 280, a mineral layer 270, and a third
geologic layer 295.
[0064] The first geologic layer 260 may begin at a ground surface
22 and extend through the formation to the mineral layer 270 and
the shale layer 280. In some embodiments, the first geologic layer
260 may include one or more additional geologic layers. For
example, the first geologic layer 260 may include one or more
porous and/or non-porous layers between the ground surface 22 and
the hydrocarbon reservoir 220 and the shale layer 280. In some
embodiments, the first geologic layer 260 may include one or more
additional hydrocarbon reservoirs 290.
[0065] The mineral layer 240 may be located above the shale layer
280 and the hydrocarbon reservoir 290 and above the third geologic
layer 295. The mineral layer 270 may include deposits of one or
more minerals and may include other deposits, such as, for example,
water. In particular, the mineral layer 270 may include one or more
of salt, limestone, dolomite, and other minerals.
[0066] The shale layer 280 is a geologic layer of non-porous or
semi-porous shale. In some embodiments, the shale layer 280 is
located below the mineral layer 270, as shown in FIG. 7. In some
embodiments, the formation 20 may not have a shale layer 280. As
shown in FIG. 7, the shale layer 280 separates the hydrocarbon
reservoir 290 from the mineral layer 270.
[0067] The formation 20 may also include the hydrocarbon reservoir
290. The hydrocarbon reservoir 290 may be located within the
formation 20 between the shale layer 280 and the third geologic
layer 295. The hydrocarbon reservoir 290 may include oil, natural
gas, or a combination of both oil and natural gas. Although
depicted as a separate layer, in some embodiments, the hydrocarbon
reservoir 290 is incorporated into other geologic layers within the
formation 20. Although depicted as having a single hydrocarbon
reservoir 290, in FIG. 7, in some embodiments the formation 20 may
include more than one hydrocarbon reservoir 290.
[0068] The formation 20 may also include a third geologic layer
295. The third geologic layer 295 may begin at the hydrocarbon
reservoir 290 and the shale layer 280 and extend through and to the
bottom of the formation 20. In some embodiments, the third geologic
layer 295 may itself include one or more additional geologic
layers. For example, the third geologic layer 295 may include one
or more porous and/or non-porous layers and one or more additional
hydrocarbon reservoirs 290.
[0069] FIG. 7 also illustrates a land-based drilling system 500
includes a drilling rig 510 positioned over a wellbore 520, and a
drill string 530 for exploring formation 20. In the illustrated
embodiment, the wellbore 520 is formed by drilling. Those of
ordinary skill in the art given the benefit of this disclosure will
appreciate that the subject matter of this disclosure also finds
application in rotary drilling and directional drilling
applications, and is not limited to land-based rigs.
[0070] The drill string 130 is suspended within the wellbore 120
and includes a downhole tool 512 as part of a bottom hole assembly
at its lower, terminal, or bottom end. The downhole tool 512 may
include a drill bit. The drill string 530 can also include a
variety of other tools, for example, reamers, logging while
drilling tools, or other drilling tools. In some embodiments, the
drill string may be a wireline tool or other tool, such as the tool
associated with acidizing minerals, removing water for the
formation 20, solution mining, or vibratory tools.
[0071] FIG. 7 also depicts portions of a process for modifying the
properties of the formation 20 and, in particular, the hydrocarbon
reservoir 290. The process includes assembling a drilling system
500, including erecting the drilling rig 510, and drilling a
wellbore 520 using, for example, a drill string 530. The wellbore
520 is drilled into the formation 20 to a depth near the depth of
the mineral layer 270. The wellbore 520 may be drilled to include a
transition section that transitions the wellbore 520 from the
vertical section of the wellbore to a horizontal section. The
wellbore 520 may be further extended to include the horizontal
section that penetrates through the cross section of the mineral
layer 270.
[0072] Other drilling and formation exploration processes may also
occur. For example, a wellbore casing may be installed in the
wellbore, the wellbore may be enlarged, for example through
reaming, formation imaging processes may take place to further
understand the properties and makeup of the formation 20, and other
processes make take place.
[0073] In the embodiment depicted in FIG. 7, the mineral layer 270
is above the hydrocarbon reservoir 290. Material removal processes
may be carried out on the mineral layer 270 such that that stress
regime within the formation 20, and in particular the hydrocarbon
reservoir 290, is changed. Changes in the stress regime may cause
movement or displacement of the shale layer 280 and/or the
hydrocarbon reservoir 290. Changes in the stress regime may also
cause cracks, not shown, to form in the hydrocarbon reservoir 290.
The cracks may increase the porosity and permeability of the
hydrocarbon reservoir 290.
[0074] Changes in the stress regime and increase in the porosity
and permeability of the hydrocarbon reservoir 290 may also cause
some of the hydrocarbons within the hydrocarbon reservoir 290 to
move into the mineral layer 270. The shale layer 280 may resist
movement of hydrocarbons from the hydrocarbon reservoir 290 to the
mineral layer 270. Formations without shale layer 280 or other
impermeable or semi-impermeable layer between the hydrocarbon
reservoir 290 and the mineral layer 270 may have greater movement
of hydrocarbons between the hydrocarbon reservoir 290 and the
mineral layer 270. The movement of hydrocarbons from the
hydrocarbon reservoir 290 to the mineral layer 270 may decrease the
difficulty in extracting the hydrocarbons as compared to
embodiments wherein the hydrocarbons remained within a lower
hydrocarbon reservoir.
[0075] FIG. 8 depicts portions of a process for modifying the
properties of a formation 30 and, in particular, the hydrocarbon
reservoir 720. The formation 30 may include one or more geologic
layers. For example, the formation 30 includes a first geologic
layer 710, a hydrocarbon reservoir 720, a mineral layer 740, and a
second geologic layer 750.
[0076] The first geologic layer 710 may begin at a ground surface
32 and extend through the formation to the second geologic layer
750. In some embodiments, the first geologic layer 710 may itself
include one or more additional geologic layers. For example, the
first geologic layer 710 may include one or more porous and/or
non-porous layers between the ground surface 32 and the second
geologic layer 750. In some embodiments, the first geologic layer
710 may include one or more additional hydrocarbon reservoirs
720.
[0077] The formation 30 may also include a second geologic layer
750. The second geologic layer 750 may begin at the bottom of the
first geologic layer and extend through and to the bottom of the
formation 30. In some embodiments, the second geologic layer 750
may itself include one or more additional geologic layers. For
example, the second geologic layer 750 may include one or more
porous and/or non-porous layers and one or more additional
hydrocarbon reservoirs 720 and/or one or more mineral layers
740.
[0078] The mineral layer 740 may be located within the second
geologic layer and adjacent, around or partially around the
hydrocarbon reservoir 720. The mineral layer 740 may include
deposits of one or more minerals and may include other deposits,
such as, for example, water. In particular, the mineral layer 740
may include one or more of salt, limestone, dolomite, and other
minerals.
[0079] The formation 30 may also include the hydrocarbon reservoir
720. The hydrocarbon reservoir 720 may be located within the
formation 20 and within the second geologic layer 750. The
hydrocarbon reservoir 720 may include oil, natural gas, or a
combination of both oil and natural gas. Although depicted as a
separate layer, in some embodiments the hydrocarbon reservoir 720
is incorporated into other geologic layers within the formation 30.
Although depicted as having a single hydrocarbon reservoir 720, in
FIG. 8, in some embodiments the formation 30 may include more than
one hydrocarbon reservoir 720.
[0080] FIG. 8 also illustrates a land-based drilling system 600
that may include a drilling rig 610 positioned over a wellbore 620,
and a drill string 630 for exploring formation 30. In the
illustrated embodiment, the wellbore 620 is formed by drilling.
Those of ordinary skill in the art given the benefit of this
disclosure will appreciate that the subject matter of this
disclosure also finds application in rotary drilling and
directional drilling applications, and is not limited to land-based
rigs.
[0081] The drill string 630 is suspended within the wellbore 620
and includes a downhole tool 612 as part of a bottom hole assembly
at its lower, terminal, or bottom end. The downhole tool 612 may
include a drill bit. The drill string 630 can also include a
variety of other tools, for example, reamers, logging while
drilling tools, or other drilling tools. In some embodiments, the
drill string may be a wireline tool or other tool, such as the tool
associated with acidizing minerals, removing water for the
formation 30, solution mining, or vibratory tools.
[0082] FIG. 8 also depicts portions of a process for modifying the
properties of the formation 30 and, in particular, the hydrocarbon
reservoir 720. The process includes assembling a drilling system
600, including erecting or assembling the drilling rig 610, and
drilling a wellbore 620 using, for example, a drill string 630. The
wellbore 620 is drilled into the formation 30 to a depth near the
depth of the mineral layer 740.
[0083] In the embodiment depicted in FIG. 8, the mineral layer 740
is adjacent the hydrocarbon reservoir 720. Material removal
processes may be carried out on the mineral layer 740 such that
that stress regime within the formation 30, and in particular the
hydrocarbon reservoir 720, is changed. Changes in the stress regime
may cause movement or displacement of the hydrocarbon reservoir
720, for example in a direction towards the mineral layer 740.
Changes in the stress regime may also cause cracks, not shown, to
form in the hydrocarbon reservoir 720. The cracks may increase the
porosity and permeability of the hydrocarbon reservoir 720. The
increase in porosity and permeability of the hydrocarbon reservoir
720 may increase the rate at which hydrocarbons may be extracted
from the hydrocarbon reservoir 720.
[0084] In addition to material removal processes, the mineral layer
740 may also be pumped up. One or more of the material removal
processes and pumping up of the mineral layer 740 may be repeated
to further change the stress regime within the hydrocarbon
reservoir. In addition, these processes may be carried out in
combination with other processes, such as hydraulic fracturing, for
further increasing the extraction of hydrocarbons from the
hydrocarbon reservoir 720.
[0085] FIG. 9 depicts an embodiment of a method for modifying a
formation 800. At block 810, a drilling rig is assembled.
Assembling a drilling rig, such as drilling rig 110, may include
erecting a mast, assembling a drilling platform, moving a drilling
boat or offshore rig over the location for the wellbore, and other
tasks associated with preparing a drill site and preparing to drill
a wellbore.
[0086] At block 820, a wellbore is drilled into a formation. The
wellbore may be a convention wellbore, for example, as depicted by
the wellbore 620 in FIG. 8, or an unconventional wellbore, for
example, as depicted by the wellbore 120 in FIG. 1. The wellbore
may include one or more horizontal, vertical, and transition
section and may be drilled into a geologic layer of the formation.
For example, the wellbore may be drilled into the mineral layer 240
of the formation 10, as depicted in FIG. 1.
[0087] Drilling a wellbore into the formation may also include
drilling a plurality of wellbores into a formation. For example, in
some embodiments, a first wellbore may be drilled into a mineral
layer, such as mineral layer 240, a second wellbore may be drilled
horizontally into a hydrocarbon reservoir, such as wellbore 320
into hydrocarbon reservoir 220, and third wellbore may be drilled
vertically into a geologic layer, such as wellbore 420 into the
hydrocarbon reservoir 220, shown in FIG. 6. In some embodiments,
the wellbore may include a secondary wellbore such as secondary
wellbore 140.
[0088] At block 830, material is removed from the formation.
Material may be removed from a geologic layer of the formation, for
example the mineral layer 240 of the formation 10. The mineral may
be removed through one or more material removal processes. For
example, in some embodiments, the mineral layer 240 may include a
salt deposit. The salt in the salt deposit may be removed using
solution mining processes or through mechanical mining processes.
In some embodiments, the geologic layer may be a mineral layer that
includes carbonate, such as limestone or dolomite. The carbonates
within the mineral layer may be removed using an acidizing process,
for example, as described in more detail above. In some
embodiments, the geologic layer may include water or other liquid
that may be removed though pumping or other liquid removal
processes.
[0089] At block 840, the formation is pressurized. In some
embodiments, the formation, and in particular, a geologic layer of
a formation, such as a mineral layer 240, may be pressurized or
pumped up, whereby fluid and/or other material is injected from a
wellbore, such as wellbore 120, and into the mineral layer, for
example, as shown and described with respect to FIG. 4, above.
[0090] At block 850, the formation is vibrated. In some
embodiments, the formation may be vibrated, for example, by using
vibrator tools within the formation. As with the material removal
processes and the pressurizing process, the vibratory process may
be used in addition to one or more of removing water from the
formation, acidizing the formation, salt mining the formation, and
other processes. The vibratory tools may cause mechanical waves,
such as seismic waves to propagate through the formation and in
particular a hydrocarbon reservoir, such as the hydrocarbon
reservoir 220.
[0091] At block 860, the properties of the formation are changed.
In some embodiments, the vibration, material removal, and/or
pressurization of the formation cause or induce changes in the
formation. For example, the mechanical waves caused by the
vibration of the formation may travel through the formation and
change the stress regime within the formation by, for example,
causing fractures within the formation, or causing one or more of
the geologic layers to settle or compact and other geologic layers
to stretch or expand. In some embodiments, during or after removal
of material from a mineral layer in proximity to a hydrocarbon
reservoir, the hydrocarbon reservoir may stretch, settle, or expand
such that cracks are formed within the hydrocarbon reservoir and
the porosity and permeability properties of the reservoir are
changed. Changing the properties of the formation may also include
increasing the completion quality of a hydrocarbon reservoir within
the formation.
[0092] At block 870, the formation is hydraulically fractured.
Hydraulic fracturing of formation, and in particular a hydrocarbon
reservoir, such as the hydrocarbon reservoir 220, may further
change the properties of the formation by increasing the porosity
and permeability of the hydrocarbon reservoir by inducing
additional cracks within the hydrocarbon reservoir.
[0093] At block 880, hydrocarbons are extracted from the formation.
In hydrocarbon extraction, the hydrocarbons within a hydrocarbon
reservoir, such as the hydrocarbon reservoir 220, may be extracted
from the formation. Hydrocarbon extraction may occur before,
during, or after the pressurization process, the vibratory process,
and the hydraulic fracturing process.
[0094] A few example embodiments have been described in detail
above; however, those skilled in the art will readily appreciate
that many modifications are possible in the example embodiments
without materially departing from the scope of the present
disclosure or the appended claims. Accordingly, such modifications
are intended to be included in the scope of this disclosure.
Likewise, while the disclosure herein contains many specifics,
these specifics should not be construed as limiting the scope of
the disclosure or of any of the appended claims, but merely as
providing information pertinent to one or more specific embodiments
that may fall within the scope of the disclosure and the appended
claims. Any described features from the various embodiments
disclosed may be employed in combination. In addition, other
embodiments of the present disclosure may also be devised which lie
within the scope of the disclosure and the appended claims.
Additions, deletions and modifications to the embodiments that fall
within the meaning and scopes of the claims are to be embraced by
the claims.
[0095] Certain embodiments and features may have been described
using a set of numerical upper limits and a set of numerical lower
limits. It should be appreciated that ranges including the
combination of any two values, e.g., the combination of any lower
value with any upper value, the combination of any two lower
values, or the combination of any two upper values are
contemplated. Certain lower limits, upper limits and ranges may
appear in one or more claims below. Numerical values are "about" or
"approximately" the indicated value, and take into account
experimental error, tolerances in manufacturing or operational
processes, and other variations that would be expected by a person
having ordinary skill in the art.
[0096] The various embodiments described above can be combined to
provide further embodiments. These and other changes can be made to
the embodiments in light of the above-detailed description. In
general, in the following claims, the terms used should not be
construed to limit the claims to the specific embodiments disclosed
in the specification and the claims, but should be construed to
include other possible embodiments along with the full scope of
equivalents to which such claims are entitled. Accordingly, the
claims are not limited by the disclosure.
* * * * *