U.S. patent application number 11/959128 was filed with the patent office on 2008-07-03 for methods for preventing proppant carryover from fractures, and gravel-packed filters.
Invention is credited to Evgeny Borisovich Barmatov, Konstantin Mikhailovich Lyapunov, Elena Mikhailovna Pershikova.
Application Number | 20080156489 11/959128 |
Document ID | / |
Family ID | 39551485 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080156489 |
Kind Code |
A1 |
Pershikova; Elena Mikhailovna ;
et al. |
July 3, 2008 |
Methods For Preventing Proppant Carryover From Fractures, And
Gravel-Packed Filters
Abstract
This invention relates to the oil and gas industry, in
particular, to methods affecting the formation productivity at the
oil and gas production stage. A method for fracture propping in a
subsurface layer, which ensures a reliable protection of wells from
the proppant carryover from the fracture, has been proposed.
According to the proposed method, a fracturing fluid is mixed with
a propping agent and particulate binding material wherein the
particles have an average length-to-width ratio of less than or
equal to about 10; thereafter, a formation fracturing process is
implemented. Then, the particulate binding material hardens and
forms a homogenous firm mass with the propping agent, which impedes
the closing of the fracture and precludes proppant carryover from
the fracture. Or, a fracturing fluid composition obtained by mixing
a propping agent with a binding compound in the form of a powder
whose size varies from about 1 to about 500 .mu.m. A gravel-packed
filter is then constructed; the said filter is based on the
application of the working fluid comprising a propping filler and
particulate binder with a length-to-width ratio of less than or
equal to 10, or comprising a propping filler and a binding compound
in the form of a powder with a size varying from about 1 to about
500 micrometers.
Inventors: |
Pershikova; Elena Mikhailovna;
(Moscow, RU) ; Barmatov; Evgeny Borisovich;
(Sipachi, RU) ; Lyapunov; Konstantin Mikhailovich;
(Novosibirsk, RU) |
Correspondence
Address: |
SCHLUMBERGER TECHNOLOGY CORPORATION;David Cate
IP DEPT., WELL STIMULATION, 110 SCHLUMBERGER DRIVE, MD1
SUGAR LAND
TX
77478
US
|
Family ID: |
39551485 |
Appl. No.: |
11/959128 |
Filed: |
December 18, 2007 |
Current U.S.
Class: |
166/280.1 ;
166/281 |
Current CPC
Class: |
C09K 8/80 20130101 |
Class at
Publication: |
166/280.1 ;
166/281 |
International
Class: |
E21B 43/267 20060101
E21B043/267 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2006 |
RU |
2006146962 |
Claims
1. A method for preventing proppant carryover from a fracture in a
subterranean formation, the method comprising the steps of: a)
providing a treatment fluid, b) mixing the treatment fluid with a
filler component comprising at least one propping agent and at
least one particulate binder having an average particle
length-to-width ratio of no more than about 10, and c) injecting
the fluid into the formation, wherein the fluid solidifies under
subterranean formation conditions.
2. The method of claim 1, wherein the particulate binder is present
in the filler component in an amount of from about 0.1% to about
99.9%.
3. The method of claim 1, wherein the filler component comprises at
least one material selected from the group consisting of
particulates having been hardened by a hydraulic hardening, air
hardening or autoclave hardening, acid-proof binding materials and
mixtures thereof.
4. The method of claim 1, in which the filler component comprises
gypsum binding materials.
5. The method of claim 4 wherein the filler component comprises
CaSO.sub.4 crystalline hydrates and anhydrites.
6. The method of claim 1, wherein the filler component c comprises
lime binding materials.
7. The method of claim 6, wherein the filler component comprises
materials selected from calcium oxides and CaO hydration &
carbonization products.
8. The method of claim 1, wherein the filler component comprises
magnesium binding materials
9. The method of claim 8, wherein the filler component comprises
magnesium oxide or a saline sealer.
10. The method of claim 1, wherein the filler component comprises a
lime-silica material comprising a mixture of CaO or Ca(OH).sub.2
with fine-milled silica which is capable of hardening at
subterranean formation temperatures.
11. The method of claim 1, wherein the filler component comprises
lime-pozzolanic and lime-slag materials.
12. The method of claim 1, wherein the filler component comprises
lime-containing components or reactive silicic acid in the form of
amorphous silica or silicate glass, whose hardening is caused by
the interaction of lime with active silica or glass with the
formation of calcium hydrosilicates.
13. The method of claim 1, wherein the filler component comprises i
slag-alkali binders comprising a constituent that includes a
caustic alkali and slag, in a vitreous state, and whose hardening
proceeds with the formation of alcaline aluminum silicates.
14. The method of claim 1, wherein the filler component comprises
cement based on high-basic calcium silicates.
15. The method of claim 1 wherein the filler component comprises at
least cement based on calcium aluminate (CaA, CA.sub.2,
C.sub.12A.sub.7), calcium sulfoaluminates, calcium fluoroaluminates
(calcium aluminate cement, high-alumina cement, sulfoaluminate
cement) or iron & sulfur-iron cements.
16. The method of claim 1, wherein the filler component comprises
calcium ferrites or calcium sulfur ferrite cements, portland
cement, roman cement, calcareous lime or mixtures thereof.
17. The method of claim 1, wherein the particulate binding
component comprises phosphates.
18. The method of claim 1, wherein the filler component comprises
watersoluble silicates.
19. The method of claim 1, wherein the filler component comprises
polymer-cement or polymer-silicate compositions comprising organic
compounds as modifying agents and inorganic compounds as the
base.
20. The method of claim 1, wherein the filler component comprises
at least one compound selected from the group consisting of hydroxy
salts of alumina, chrome, zirconium, colloidal silica solutions,
partly dehydrated crystalline hydrates of aluminum sulfates and
calcium aluminates.
21. The method of claim 1, wherein at least one of the treatment
fluid or the filler component further comprises at least one as
additive selected from the group consisting of polymers, barite
particles, red iron ore, glass beads, porous particles, sand with
polymeric coating, ceramic particles, sand, cured or curable
proppants and sands, swollen expanded clay, vermiculite,
agloporite, deformable particles, adhesive materials and fibrous
materials.
22. The method of claim 1 wherein said filler component comprises
at least one particulate filler having an average particle size of
from 0.5 to 500 .mu.m.
23. The method of claim 1, in which the density of the particulate
binder varies from 0.5 to approximately 5 g/cm.sup.3.
24. A method of fracturing a subterranean formation, the method
comprising the steps of: a) providing a treatment fluid, b) mixing
the treatment fluid with a filler component comprising at least one
propping agent and at least one particulate binder having an
average particle length-to-width ratio of no more than about 10,
and c) injecting the fluid into the formation, and d) fracturing
the formation, wherein the fluid solidifies under subterranean
formation conditions.
25. A gravel-packed filter obtained by application of a method
according to claim 1.
Description
[0001] This application claims foreign priority benefits to Russian
Patent Application No. 2006146962, filed on Dec. 28, 2006.
FIELD OF THE INVENTION
[0002] This invention relates to the oil and gas industry, in
particular, to methods affecting the formation productivity at the
oil and gas production stage.
BACKGROUND OF THE INVENTION
[0003] The statements in this section merely provide background
information related to the present disclosure and may not
constitute prior art.
[0004] A carryover of proppant from a fracture to the well at the
post-fracturing period either during the initial cleaning or even
after completion of the well construction is a crucial issue for
the oil production sector. Up to 20% of proppant can be conveyed
into the well, which, can lead to negative consequences. In
marginal wells, proppant settles in a casing; thus, regular
washings are required and the cost of well repair operations grows.
Premature wear and failure of electrical submersible pumps is
another consequence of the carryover of unbound proppant or other
solid particles of rocks. Also, oil or gas production decreases
occur due to a significant loss of the near wellbore conductivity
caused as a result of a reduced fracture thickness or overlapping
of a production zone.
[0005] At present, several methods to decrease in the carryover of
proppant or other propping agents from the facture are known.
[0006] The most common approach is based on the application of
proppant with a hardening resin coating, which is injected into the
fracture at the end of the treatment process. However, the use of
this type of proppant produces undesired chemical reactions of the
resin coating with the fracturing fluid. This interaction causes
partial degradation and disintegration of the coating, thus
reducing the contact strength among proppant particles and,
therefore, decreasing the proppant pack strength. Further, the
interaction between the resin coating components and fracturing
fluid components causes uncontrolled changes in the rheological
properties of the fluid, which also diminishes the fracturing
process efficiency. Extended well closure periods could
significantly reduce the proppant filler strength.
[0007] In another method, fibrous materials are mixed with a
propping agent and added to limit proppant conveyance; in this
process, the combination of fibers and proppant particles increase
the proppant strength and restrict the back-flow carryover of the
proppant. The addition of fibers enables a more effective
redistribution of loads of the proppant. A fibrous structure is
more flexible as compared to cured resin proppant and allows
movements of proppant-fibrous filler without deterioration of
strength.
[0008] In another method, fiber bundles comprising about 5 to 200
separate fibers are used. In this process, the fiber bundle
structure may be fixed on one side.
[0009] Mixing proppant with deformable beads or particles is also
known. The deformable particles are polymeric and may have various
shapes; however, a maximum length-to-base ratio of equal to or less
than 5 is preferable. Deformable particles can be homogeneous
spheres formed from one compound or may be composite particles
containing a non-deformable core and a deformable coating. In
another embodiment, the core consists of deformable materials and
could include milled or crushed materials, e.g., nutshell, seed
shell, fruits kernels and processed wood.
[0010] Mixtures of proppant with adhesive polymeric materials have
also been used. The adhesive compositions contain and cover the
particles with a thin sticky layer. As a result, particles adhere
to each other as well as to sand particles or crushed fragments of
the propping agent. This completely prevents the carryover of solid
particles from the fracture. Adhesive materials can also be
combined with other chemical agents used in the formation
fracturing process, e.g., retarding agents, antimicrobial agents,
polymer gel destructors, as well as antioxidant and wax-formation
and corrosion retarding agents. Mixtures of adhesive materials with
deformable particles have also been used.
[0011] Thermoplastic materials have also been used with proppants.
When mixed with a propping agent, the thermoplastics soften upon
exposure to high temperatures, and thereafter they adhere to the
propping agent to form aggregates. Thermoplastic agents may also be
used with resin proppants.
[0012] Another method describes the application of a fracturing
fluid which is a self-degrading cement comprising an acid, which
interacts with other components to cause the formation of a cement
material, as well as a degrading component, which could
disintegrate under the fracture conditions and cause the formation
of cavities in the cement.
[0013] Another method describes the formation fracturing process
using a hydrated cement particles with average particle sizes
ranging from 5 .mu.m to 2.5 cm.
SUMMARY OF THE INVENTION
[0014] The invention provides methods for fracture propping in the
oil and gas industry, in particular, to the development of a method
for preventing carryover of proppant from fractures.
[0015] Specifically, the invention provides methods for fracture
propping in an subterranean formation which provides reliable
protection of the well from excess proppant conveyance from the
fracture.
[0016] Specifically, the invention provides a method in which a
formation fracturing fluid is mixed with a filler component
comprising at least one propping agent and at least one particulate
binder wherein the particulate binder particles have an average
length-to-width ratio of equal to or less than about 10, and
thereafter, a formation fracturing process is implemented. The
particulate binding material is then solidified to form a
homogeneous firm mass with the propping agent, which obstructs the
closure of the fracture and precludes the proppant carryover.
[0017] The invention further provides fracturing fluid compositions
obtained by mixing a propping filler and a particulate binder with
a length-to-width ratio of equal to or less than 10, which could
solidify under underground formation conditions.
[0018] The invention further provides fracturing fluid compositions
obtained by mixing a propping filler and a particulate binding
composition in the form of a powder, whose size varies from about 1
.mu.m to about 500 .mu.m. In this case, powder-like particles of
the binder get into contact with the propping filler and are then
solidified, increasing the propping filler pack strength.
[0019] In one embodiment, the fracturing fluid compositions are
obtained by mixing a propping filler and a particulate or powder
binding material as well as other components obstructing the
proppant conveyance from the fracture, including deformable
particles and adhesive and fiber-like materials.
[0020] The invention further provides a gravel-packed filter which
is based on the application of a working fluid comprising a
propping filler and a particulate binder with a length-to-width
ratio of equal to or less than 10, or comprising a propping filler
and a particulate binding composition in the form of a powder,
whose size varies from about 1 .mu.m to about 500 .mu.m.
DETAILED DESCRIPTION OF THE INVENTION
[0021] 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. The description and examples are
presented solely for the purpose of illustrating the preferred
embodiments of the invention and should not be construed as a
limitation to the scope and applicability of the invention. While
the compositions of the present invention are described herein as
comprising certain materials, it should be understood that the
composition could optionally comprise two or more chemically
different materials. In addition, the composition can also comprise
some components other than the ones already cited. In the summary
of the invention 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 of the invention 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 possession of
the entire range and all points within the range.
[0022] The compositions may contain one or more than one of the
below-listed materials as propping fillers: ceramic particles and
sand particles having different shapes, solidified and curable
proppants and sands; swollen expanded clay, vermiculite, and
agloporite. Further, proppants or polymer-coated sand can be used
as a propping filler.
[0023] Granulated and powdered binders can be added in a fracturing
fluid in a dry state, or in other forms such as suspensions in
water, working fluids, gels or other suitable solvent containing
forms, including those modified with various surfactants.
[0024] Useful binders for particulate binders include but are not
limited to the following. The components may be hardened by
hydraulic, air and autoclave hardening and may include acid-proof
binding materials and mixtures of such materials.
[0025] Useful materials include those based on of crystalline
hydrates CaSO.sub.4 and anhydrite (gypsum binding materials);
materials based on CaO, CaO hydration and carbonization products
(lime binding materials) and the like; materials based on MgO and
saline sealers (magnesium binding materials); lime-silica binding
materials comprising mixtures of CaO or Ca(OH).sub.2 with
fine-milled silica, which solidify at increased temperatures;
lime-pozzolanic and lime-cindery binding materials comprising a
lime-containing component and a reactive silicic acid in the form
of amorphous silica or silicate glass, whose hardening occurs due
to the interaction of a lime with an active silicon oxide or glass
with the formation of calcium hydrosilicates.
[0026] Other useful materials include slag-alkali binding materials
having a component comprising caustic alkali and slag, preferably
in a vitreous state, whose hardening is connected with the
formation of alcaline aluminum silicate.
[0027] Binding cements such as high-basic calcium silicates
(portland cement clinker, natural cement, calcareous cement,
hydraulic lime, and the like) are also useful. The binding
properties of these materials are essentially predefined by
hydration of tricalcium (Ca.sub.3SiO.sub.5) and dicalcium
(Ca.sub.2SiO.sub.4) silicates, including slag-portland cement,
cements based on low-basic calcium aluminates (CaA, CA.sub.2,
C.sub.12A.sub.7) and derivatives, thereof, e.g., calcium
sulfoaluminates, calcium fluoroaluminates (aluminate cement,
high-alumina cement, sulfoaluminate cement); high iron oxide
cements and sulfur high iron oxide cements. Cements based on
calcium ferrites and their derivatives such as calcium
sulfoferrites may also be used.
[0028] Phosphate binding materials (cement and binding materials),
which harden due to phosphate formation are also useful.
[0029] Watersoluble silicate materials, including but not limited
to alkali metal silicates (soluble glasses) and organic base
silicates
[0030] Also useful are polymer-cement compositions and
polymer-silicate binding compositions containing organic
compositions as modifying components and inorganic binding
materials (cement, soluble glass) as the base;
[0031] Hydroxy salts of aluminum, chrome, zirconium, colloidal
solution of silica and aluminum oxide, partially dehydrated
crystalline hydrates of aluminum sulfates and calcium aluminates
may also be used.
[0032] A particulate binder may comprise a single component, or
have a multi-component composition. In addition to binders, the
particulate binder may include components which improve required
strength properties (e.g., polymers) and density properties (e.g.,
particles of barite, red iron ore, glass beads, porous
particles).
[0033] The particulate binders can be provided in a variety of
shapes, including but not limited to, spherical, cylindrical,
sparry, cubic, oval, flaked, scaly, irregular shape, or a
combination of the above-mentioned shapes, so long as the particles
have a length-to-width ratio to be equal to or less than about
10.
[0034] The content of particulate binding filler in the total
volume of propping and particulate fillers varies in the range from
about 0.1 to about 99.9% by weight. The actual density of the
particulate binding agent varies in the range from about 0.3 to
about 5 g/cm.sup.3.
[0035] At least one of the following binders of the classes can be
used, such components may be hardened by methods such as hydraulic,
air and autoclave hardening as well as acid-proof binding materials
as well as mixtures thereof, including but not limited to materials
based on crystalline hydrates CaSO.sub.4 and anhydrite (gypsum
binding materials); materials based on CaO, CaO hydrates and
carbonization products (lime binding materials); materials on the
basis of MgO and saline sealers (magnesium binding materials)
[0036] Useful materials include those based on of crystalline
hydrates CaSO.sub.4 and anhydrite (gypsum binding materials);
materials based on CaO, CaO hydration and carbonization products
(lime binding materials) and the like; materials based on MgO and
saline sealers (magnesium binding materials); lime-silica binding
materials comprising mixtures of CaO or Ca(OH).sub.2 with
fine-milled silica, which solidify at increased temperatures;
lime-pozzolanic and lime-cindery binding materials comprising a
lime-containing component and a reactive silicic acid in the form
of amorphous silica or silicate glass, whose hardening occurs due
to the interaction of a lime with an active silicon oxide or glass
with the formation of calcium hydrosilicates.
[0037] Other useful materials include slag-alkali binding materials
having a component comprising caustic alkali and slag, preferably
in a vitreous state, whose hardening is connected with the
formation of alcaline aluminum silicate.
[0038] Binding cements such as high-basic calcium silicates
(portland cement clinker, natural cement, calcareous cement,
hydraulic lime, and the like) are also useful. The binding
properties of these materials are essentially predefined by
hydration of tricalcium (Ca.sub.3SiO.sub.5) and dicalcium
(Ca.sub.2SiO.sub.4) silicates, including slag-portland cement,
cements based on low-basic calcium aluminates (CaA, CA.sub.2,
C.sub.12A.sub.7) and derivatives, thereof, e.g., calcium
sulfoaluminates, calcium fluoroaluminates (aluminate cement,
high-alumina cement, sulfoaluminate cement); high iron oxide
cements and sulfur high iron oxide cements. Cements based on
calcium ferrites and their derivatives such as calcium
sulfoferrites may also be used.
[0039] Phosphate binding materials (cement and binding materials),
which harden due to phosphate formation are also useful.
[0040] Watersoluble silicate materials, including alkali metal
silicates (soluble glasses) and organic base silicates
[0041] Also useful are polymer-cement compositions and
polymer-silicate binding compositions containing organic
compositions as modifying components and inorganic binding
materials (cement, soluble glass) as the base;
[0042] Hydroxy salts of aluminum, chrome, zirconium, colloidal
solution of silica and aluminum oxide, partially dehydrated
crystalline hydrates of aluminum sulfates and calcium aluminates
may also be used.
[0043] The average particle size of useful particulate binding
materials or binders ranges from about 0.5 to about 500 .mu.m. The
concentration of the particulate binding materials in the propping
filler varies from about 0.1 to about 99.9% by weight.
[0044] The density of the powder-like binding materials can vary
from about 0.5 to about 5 g/cm.sup.3.
[0045] Such granulated or powder-like binding materials will be
used in a mixture with a propping agent; the concentration of the
propping agent in the mixture could vary in the range of about 0.1
to about 99.9%.
[0046] The terms granulated, powder-like, and particulate are used
interchangeably herein. Granulated or powder-like binding materials
may be added to the propping fluid either in a dry state or in
other forms such as suspensions in water, working fluids, gels or
other suitable solutions including those modified by various
surfactants.
[0047] Embodiments of the invention may use other additives and
chemicals that are known to be commonly used in oilfield
applications by those skilled in the art. These include, but are
not necessarily limited to, materials in addition to those
mentioned hereinabove, such as breaker aids, oxygen scavengers,
alcohols, scale inhibitors, corrosion inhibitors, fluid-loss
additives, bactericides, iron control agents, organic solvents, and
the like. Also, they may include a co-surfactant to optimize
viscosity or to minimize the formation of stabilized emulsions that
contain components of crude oil, or as described hereinabove, a
polysaccharide or chemically modified polysaccharide, natural
polymers and derivatives of natural polymers, such as cellulose,
derivatized cellulose, guar gum, derivatized guar gum, or
biopolymers such as xanthan, diutan, and scleroglucan, synthetic
polymers such as polyacrylamides and polyacrylamide copolymers,
oxidizers such as persulfates, peroxides, bromates, chlorates,
chlorites, periodates, and the like. Some examples of organic
solvents include ethylene glycol monobutyl ether, isopropyl
alcohol, methanol, glycerol, ethylene glycol, mineral oil, mineral
oil without substantial aromatic content, and the like.
* * * * *