U.S. patent application number 12/817881 was filed with the patent office on 2011-12-22 for degradable material for different oilfield applications.
Invention is credited to Carlos Abad, Gregory Kubala, Hemant K.J. Ladva, Mohan K.R. Panga.
Application Number | 20110308802 12/817881 |
Document ID | / |
Family ID | 45327653 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110308802 |
Kind Code |
A1 |
Ladva; Hemant K.J. ; et
al. |
December 22, 2011 |
DEGRADABLE MATERIAL FOR DIFFERENT OILFIELD APPLICATIONS
Abstract
This invention relates to compositions and methods A method of
treating a subterranean formation including forming a fluid
comprising zein, and introducing the fluid to a subterranean
formation. A method of treating a subterranean formation comprising
a wellbore, including introducing a tubular to the wellbore wherein
the tubular comprises zein.
Inventors: |
Ladva; Hemant K.J.;
(Missouri City, TX) ; Abad; Carlos; (Richmond,
TX) ; Panga; Mohan K.R.; (Stafford, TX) ;
Kubala; Gregory; (Houston, TX) |
Family ID: |
45327653 |
Appl. No.: |
12/817881 |
Filed: |
June 17, 2010 |
Current U.S.
Class: |
166/305.1 |
Current CPC
Class: |
C09K 8/035 20130101;
E21B 43/25 20130101; C09K 8/805 20130101; C09K 8/68 20130101 |
Class at
Publication: |
166/305.1 |
International
Class: |
E21B 43/16 20060101
E21B043/16 |
Claims
1. A method of treating a subterranean formation, comprising:
forming a fluid comprising zein; and introducing the fluid to a
subterranean formation.
2. The method of claim 1, wherein the fluid further comprises
methanol, ethylene glycol, ethanol, or a mixture thereof.
3. The method of claim 1, wherein the fluid further comprises
1-butyl-3-methylimidazolium chloride or 1-ethyl-3 methylimidalolium
ethylsulfate.
4. The method of claim 1, further comprising altering the
wettability of a surface of the subterranean formation or a
particle in the fluid.
5. The method of claim 1, wherein the fluid further comprises
starch.
6. The method of claim 1, wherein the fluid is an energized fluid
or foam.
7. A method, comprising: introducing a tubular to the wellbore,
wherein the tubular comprises zein.
8. The method of claim 7, wherein the zein is uniformly distributed
across the surface of the tubular.
9. The method of claim 7, wherein the zein is distributed across
the surface of the tubular to facilitate the formation of
perforations in the tubular.
10. The method of claim 9, wherein the zein degrades over time.
11. The method of claim 7, the tubular comprises metal.
12. The method of claim 7, wherein the tubular is a non conductive,
electrically transparent tubular.
13. The method of claim 7, further comprising NMR logging and/or
resistivity measurements.
14. The method of claim 7, wherein the tubular is a canister.
15. A method of treating a subterranean formation comprising a
wellbore, comprising: forming a fluid comprising zein; and
introducing the fluid to the wellbore.
16. The method of claim 15, wherein the zein encapsulates a
chemical that is released as the zein degrades.
17. The method of claim 15, wherein the zein encapsulates a solid
particle.
18. The method of claim 17, wherein a flowback of the particle is
prevented.
19. The method of claim 17, wherein a particle transport of the
fluid is more effective than if no zein were in the fluid.
20. The method of claim 15, wherein the fluid further comprises a
crosslinker.
21. The method of claim 20, wherein the crosslinker comprises
borate or zirconium.
22. The method of claim 15, wherein the fluid has a viscosity that
is higher than if no zein were in the fluid.
23. The method of claim 15, wherein the shape and/or size of the
zein is selected to control fluid loss or diversion.
24. The method of claim 15, wherein the zein has a shape selected
from the group consisting of fibers, particulates, tubulars, rods,
containers, or a combination thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to methods and fluids used in
treating a subterranean formation. In particular, the invention
relates to the preparation and use of fluid delivery systems
comprising a biodegradable material.
[0003] 2. Description of the Related Art
[0004] The demand for degradable materials specifically for
oilfield applications has become increasingly important over the
years as cost, formation conditions, and environmental regulations
often limit the use of common polymeric materials.
[0005] There is a broad range of degradable polymers that may be
used in the oil field services industry such as polysaccharides
(e.g. starch, guar, chitosan, hydroxypropyl guar, hydroxymethyl
guar, xanthan, hydroxyethyl cellulose) and proteins (e.g. collagen,
fibrin, and gelatin). Synthetic degradable polymers derived from
polyesters, polyanhydride and polyamide have also been developed to
target specific applications. Starch is currently used in oilfield
applications such as fracturing, drilling and diversion. In
fracturing application starch is mainly used as a fluid loss
additive. Starch is also used as a viscosifier and as a fluid loss
additive in drilling fluids. In these applications the starch is
not fully solubilized and is deposited onto the fracture surface or
formation wall as part of the filtercake. Considerable effort is
placed in the cleanup of filter cakes e.g. prior to gravel packing
to ensure minimum impairment to flow of formation fluids. The mode
of degrading the polymers is through hydrolysis, oxidation or
exposure to heat. Some biopolymers may be degraded through the use
of enzymes however, it has temperature limitations. In any event, a
low cost, reliable, readily available material is desirable for use
in the oil field services industry.
SUMMARY
[0006] Embodiments of this invention relate to compositions and
methods of treating a subterranean formation including forming a
fluid comprising zein, and introducing the fluid to a subterranean
formation. Embodiments of this invention relate to compositions and
methods of treating a subterranean formation comprising a wellbore,
including introducing a tubular to the wellbore wherein the tubular
comprises zein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a plot of viscosity as a function of shear rate of
an embodiment of the invention.
[0008] FIG. 2 is a schematic view of a tubular comprising an
embodiment of the invention.
[0009] FIG. 3 is a schematic view of a tubular comprising an
additional embodiment of the invention.
[0010] FIG. 4 is a schematic view of a tubular comprising an
additional embodiment of the invention.
DETAILED DESCRIPTION
[0011] 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.
[0012] In the summary of the invention and this 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 have
disclosed and enabled the entire range and all points within the
range.
[0013] Generally, zein may be selected for a variety of oil field
services applications. Furthermore, the material properties can be
adjusted to target a wide range of specific oilfield applications.
The degradability of the material can be controlled by using
different chemistries. The applications that can be targeted ranges
from swelling packers, degradable completion hardware, degradable
canister, screenless completions, degradable bridge or temporary
plugs, degradable piping, degradable fluid loss additive, surface
modification of proppants, coatings on breakers, coated additives,
coating as barriers to oil or water, coating for controlled release
of materials with controlled delivery, reactive coating on
proppants that become sticky, diversion, lost circulation,
conformance, water control, drilling, cementing, gravel packing,
wormhole, etc. Shapes and sizes of zein particles or particles
coated with zein may be selected to control fluid loss and
diversion.
[0014] Some embodiments may benefit from using zein to coat the
proppant to change its wettability profile. Likewise, some
embodiments may benefit from using zein to change the wettability
profile of the subterranean formation.
[0015] Zein is 45-50 percent of the protein present in corn. It is
a group of alcohol soluble proteins (prolamins) found in corn
endosperm. Centrifugal separation of starch from the endosperm
leaves protein rich mass (corn gluten) from which zein is
extracted. It is rich in glutamic acid, leucine, alanine and
proline that gives it high hydrophobicity. Zein is an alcohol
soluble protein and exhibits hydrophobic properties and low water
uptake. Zein has alpha, beta, and gamma protein fractions. Alpha
accounts from 75-85 percent of the total protein and is dominated
by Z19 and Z22 protein corresponding to 19 kDa and 22 kDa molecular
weight. Zein is commercially available from Sigma-Aldrich of
Houston, Tex., Showa Sangyo Co Ltd of Japan and Freeman Industries
of Tuckahoe, N.Y.
[0016] Zein can form tough greaseproof coatings, with flexibility
and compressibility. Zein is commercially utilized due to its film
formation capability in the food and pharmaceutical industries. The
thin films of zein are formed that may be edible or may be utilized
in biodegradable packaging.
[0017] Zein films on its own are generally brittle but when the
films are plasticized they are flexible. Addition of different
plasticizers and cross linkers will give films of different
mechanical and barrier properties that could be utilized
accordingly for specific applications. Plasticization and
crosslinking affects its mechanical and barrier properties.
Polyethylene glycol and glycerol are effective plasticizer for zein
dispersion. Zein dissolves in ethyl alcohol/water 90/10 w/w
mixture. Stability of the aqueous zein dispersion is dependent on
pH and electrolyte content. The dispersion is stable at pH of 3-4.
Glass transition temperature of pure zein powder is 170.8 C. Zein
dissolves in ethanol and is hydrophobic. Water resistance of zein
can be achieved by modifying the hydrophilic side groups such
NH.sub.2, OH, COOH, and SH by hydrophobic groups.
[0018] Common plasticizers for zein include glycerol, glyceryl
monoesters, PEG and fatty acids. Zein is also plasticized by water
although it is not soluble in water. Additional plasticizers
include glycols such as triethylene glycol, propylene glycol,
ethylene glycol, polyethylene glycol, and polypropylene glycol;
sulfonamides such as benzene sulfonamide, N-ethyl benzene
sulfonamide, p-toluene sulfonamide, and N-ethyl p-toluene
sulfonamide; fatty acids such as oleic acid, palmitic acid,
myristic acid, and stearic acid; amides such as acetamide,
acetanilide, and urea; amides such as triethanolamine and
diethanolamine; glyceryl esters such as glyceryl monooleate,
glyceryl monopalmitate, and glyceryl monostearate; glycol esters
such as glycol monooleate, glycol monopalmitate, and glycol
monostearate; esters such as dibutyl tartrate, monobutyl phthalate,
monomethyl azelate, and monomethyl sebacate; ethylene glycol
monophenyl ether, tricresyl phosphate, tall oil, glycerol,
sorbitol, diphenylamine, dibutyl phthalate, dibutyl sebacate, and
triphenyl phosphate.
[0019] Zein on its own has a glass transition temperature of
139.degree. C. and its glass transition temperature decreases
rapidly with moisture content. Zein may be utilized in the oilfield
applications as a tunable glass transition temperature material
e.g. in forming a plug of zein that is later removed due to
absorption of water and lowering of glass transition
temperature.
[0020] Biodegradable fibers of zein on its own or its blend with
other polymers such as chitosan may also be used as additives in
drilling fluid, fracturing fluids or cement. These fibres could be
used to generate diversion during fracturing operations, in the
form of plugs, in the form of near wellbore screenouts, or in the
form of far field diversion pills. The fibers could be also used as
proppant suspension additives or as lost circulation material.
Fibers of zein could also be used as strengthening fillers for
materials requiring improved compressive, tensile or shear
properties, such as cement, plugs, darts for applications such as
treat and produce completions, etc.
[0021] Zein could be used to generate thermoplastic parts and
pieces, such as plugs for low temperature applications where the
material is to be insoluble in water and oil, but might be
solubilized and thus removed by injection of alcohol blends of
specific composition.
[0022] Zein can be also used in order to prepare melt composites
with polyester materials, to alter the mechanical properties and
the dissolution and degradation rate of said polyesters to acid,
base and alcohol initiated hydrolysis alcoholysis. Zein would be
used to alter the Tg and Tm (glass transition temperature, melting
temperature) of the blend resulting typically in plasticized
polymers, or polymers which would more easily swell, resulting in
materials with enhanced degradation rates. This would be used for
low temperature fiber applications.
[0023] Zein may be adsorbed preferentially on hydrophobic or
hydrophilic surfaces. Such surface modification with zein may be
used on proppant coating or targeting specific sites in the
subterranean formation. Zein may be used as binding agent e.g. in
proppant and preventing proppant flowback.
[0024] Zein may be used for some parts of conventional completions
that will eventually degrade. Zein articles are degradable with
temperature, time, and solvents. Zein articles may be made of
different size and shape including fibers, particulates, tubulars,
rods, and containers. In some embodiments, the material may be used
for casing, cementing, or general completions operations. In some
embodiments, perforating steps may benefit from using materials
comprising zein.
[0025] Zein may be used as a viscosifier. Zein may be x-linked to
give unique material properties for oilfield applications.
Crosslinkers such as borates, zirconium, or other crosslinkers
often used in fracturing fluids may also be desirable for fluids
comprising zein. Some zein compositions may benefit from further
comprising other polymers such as guar or modified guar. Some
compositions comprising zein may be used to form energized fluids
and/or foams.
[0026] In some embodiments, the material may be especially
desirable as a coating to protect from brine-based degradation. In
some embodiments, small particles and/or chemicals may be
encapsulated with the material for process steps that include the
presence of brine.
[0027] Generally, zein may be used to encapsulate acids or oils for
controlled release. Biodegradable nanospherical particles may be
formed using zein to encapsulate solids such as breakers and
liquids such as acids and alkalis. Zein may be used as an oxygen
barrier e.g. in sensors since zein has excellent resistance to
oxygen permeation. Zein may be used to protect encapsulated
material from oxidation due to its pronounced oxygen barrier
property. Zein may be used individually or blended with other
resins such as rosin or neutral resins for coating proppants. The
coated proppant may aid proppant transport during fracturing. Zein
may be used to coat tubulars to prevent corrosion. Zein coating on
tubulars to give improved cement bonding.
[0028] Zein and fatty acid resin may be used for preparing semi
solid resin plugs in oilfield applications. Zein may also be used
as a barrier to oil and grease e.g. temporary plugs made from zein
are dissolved using specific solvent such as methanol, ethylene
glycol, DEG, ethyl ether, furfuryl alcohol, ethyl alcohol/water
90/10 w/w, acetic acid, lactic acid, citric acid,
phenol+alcohol+water, ionic liquids (e.g.
1-butyl-3-methylimidazolium chloride), benzene, toluene, xylene and
acetone. Examples of solvents include acetamide, acetic acid,
2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1-propanol,
2-amino-2-methyl-1,3-propanediol, o-aminophenol, m-aminophenol,
aniline, benzyl alcohol, benzyl cellosolve, butylamine, butyl
tartrate, 1,3-butylene glycol, o-cyclohexylphenol,
1,3-diaminopropanol, di[-.beta.-hydroxyethyl]janiline,
diethanolamine, diethylene glycol, diethylene glycol monoethyl
ether (carbitol), diethylene glycol monomethyl ether (methyl
carbitol), diethylenetriamine, diglycol chlorohydrins,
diisopropanolamine, diphenylquanidine, a-diphenylthiourea,
dipropylene glycol, ethyl ether tripropylene glycol, ethyl lactate,
ethylphenylethanolamine, ethylene chlorohydrins, ethylene glycol,
ethylene glycol monoethyl ether (cellosolve), ethylene glycol
monomethyl ether (methyl cellosolve), ethylenediamine, formic acid,
furfuryl alcohol, glycerol, glycerol furfural,
glyceryl-.alpha.-.gamma.-dichlorohydrin,
glyceryl-.alpha.-.gamma.-dimethyl ether,
glyceryl-.alpha.-monochlorohydrin, glyceryl-.alpha.-methyl ether,
glyceryl-.alpha.-phenyl ether, .beta.-hydroxyethylaniline,
hydroxyethylethylenediamine, 2-hydroxymethyl-1.3-dioxolane, lactic
acid, methyl alcohol, methyl lactate, monoethanolamine,
monoisopropanolamine, morpholine, morpholine ethanol, phenol,
phenyl cellosolve, phenyldiethanolamine, phenylethanolamine,
propionic acid, propylene chlorohydrins, propylenediamine,
propylene glycol, pyridine, resorcinol monoacetate,
triethanolamine, triethylenetetramine, tetrahydrofurfuryl alcohol,
triethylene glycol, triisopropanolamine, and trimethylaminomethane.
Additional solvents include water with acetone, acetonyl acetone,
n-butanol, t-butanol, s-butanol, dioxalane, dioxane, ethanol,
isobutanol, isopropanol, methanol, or n-propanol. More examples of
solvents include a lower aliphatic alcohol with acetaldehyde,
acetone, benzene, butyl lactate, chloroform, dichloromethane,
diethylene glycol monoethyl ether, ethyl lactate, ethylene,
dichloride, ethylene glycol, ethylene glycol monoethyl ether,
furfural, methyl ethyl ketone, methylene chloride, nitroethane,
nitromethane, propylene glycol, 1,1,2,2-tetrachloroethane,
1,2,3-trichloroethane, or toluene.
[0029] The use of ionic liquids may therefore be considered for not
only the cleanup of filtercakes containing starch but also
filtercakes containing zein or other biopolymers.
1-ethyl-3-methylimidazolium ethylsulfate (EMIMEtOSO3) ionic liquid
may also be used to dissolve polymers such as guar, starch and
zein. The ionic liquid may also be used as a pre flush and post
flush fluid in gravel pack operations. Additional examples of ionic
liquids include 1-ethyl-3-methylimidazolium chloride,
1-ethyl-3-methylimidazolium methanesulfonate,
1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium
methanesulfonate, 1-ethyl-2,3-di-methylimidazolium ethylsulfate,
methylimidazolium chloride, methylimidazolium hydrogensulfate,
1-ethyl-3-methylimidazolium hydrogensulfate,
1-ethyl-3-methylimidazolium tetrachloroaluminate,
1-butyl-3-methylimidazolium hydrogensulfate,
1-butyl-3-methylimidazolium tetrachloroaluminate,
1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium
acetate, 1-ethyl-3-methylimidazolium ethylsulfate,
1-butyl-3-methylimidazolium methylsulfate,
1-ethyl-3-methylimidazolium thiocyanate,
1-butyl-3-methylimidazolium thiocyanate, choline acetate,
1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and
1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
[0030] Finally, zein may be used to suppress scaling especially
with calcium or magnesium in either high or low temperature
wells.
EXAMPLES
[0031] The following examples are presented to illustrate the
preparation and properties of fluid systems, and should not be
construed to limit the scope of the invention, unless otherwise
expressly indicated in the appended claims. All percentages,
concentrations, ratios, parts, etc. are by weight unless otherwise
noted or apparent from the context of their use.
[0032] The following Examples, unless described differently, used a
commodity grade sample of zein that is commercially available from
Sigma Aldrich with a standard moisture content.
Example 1
[0033] This example uses ionic liquid such as
1-butyl-3-methylimidazolium chloride (BMIM Cl) for filtercake
cleanup containing biopolymers such as starch and zein.
[0034] Biopolymers such as starch and zein are soluble in ionic
liquids up to 10% w/w concentration at 80.degree. C.
1-Butyl-3-methylimidazolium chloride (BMIM Cl) ionic liquid is
effective in solubilizing such biopolymers. Photographs show that
5% w/w of zein and starch that are insoluble in water and are
soluble in 20% BMIMCl/80% water mixture at 80 C.
Example 2
[0035] Zein may be used to form solid plugs e.g. degradable plugs
or it may be used as zonal isolation plugs. Photographs show that
zein is progressively more soluble as the concentration of zein
increases at 1, 5, and 10 percent zein. This shows that plugs made
from zein and utilized downhole may be dissolved using ethylene
glycol.
Example 3
[0036] Zein may be used as a viscosifier for fluids used in
subterranean formation. FIG. 1 is a plot of viscosity as a function
of shear rate of an embodiment of the invention. FIG. 1 shows the
effect of zein concentration on viscosity, as zein concentration
increases, viscosity increases. Ethylene glycol was used as a base
fluid to solubilize zein.
Example 4
[0037] Using different ratio mixtures of methanol and water zein
plugs were formed having different properties. Photographs show
that a swollen and compressible plug was formed using 10% methanol
and 90% water. In contrast a mixture with 50% methanol and 50%
water formed a competent plug. 20, 30, and 40 percent methanol
mixtures formed plugs with progressively more compact
properties.
Example 5
[0038] Photographs show that zein particles are insoluble in
ethylene glycol at 25 C however at 60 C they are completely
soluble. This property indicates that diversion and cleanup
applications may benefit from using this composition.
Example 6
[0039] A composite casing or tubular may be considered. FIG. 2
illustrates an embodiment of a tubular. Such tubular will allow
logging through casing of formation fluids. The composite
tubulars/casings have the distinct advantage over the metallic
tubular/casings since their non conductive properties makes them
electrically transparent. In additions such tubulars are also
transparent to NMR logging and/or resistivity measurements. In some
embodiments, the material may be degradable, also. In some
embodiments, the casing or tubular may comprise a canister.
Example 7
[0040] FIG. 3 is a schematic view of a tubular comprising an
additional embodiment of the invention. A metallic tubular that
includes degradable material in a specific formatted array such
that the degradable material disappears with time and creates
perforations in the tubular. This concept may be used also to form
a screen for sand control purposes. The shape and size of the
degradable material may be varied.
Example 8
[0041] FIG. 4 is a schematic view of a tubular comprising an
additional embodiment of the invention. Varying the striations may
be desirable for perforating process steps. Some embodiments of the
invention may benefit from a non conductive, electrically
transparent tubular.
ADVANTAGES
[0042] The use of ionic liquids for the cleanup of biopolymers in
the oil industry has immense economic implications on well services
business including stimulation, fracturing, diversion, cementing
and gravel packing.
[0043] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. Furthermore, no limitations
are intended to the details herein shown, other than as described
in the claims below. It is therefore evident that the particular
embodiments disclosed above may be altered or modified and all such
variations are considered within the scope and spirit of the
invention. Accordingly, the protection sought herein is as set
forth in the claims below.
* * * * *