CA1134300A - Process for treating xanthomonas fermentation broth for use in displacement of oil from partially depleted reservoirs - Google Patents
Process for treating xanthomonas fermentation broth for use in displacement of oil from partially depleted reservoirsInfo
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- CA1134300A CA1134300A CA339,181A CA339181A CA1134300A CA 1134300 A CA1134300 A CA 1134300A CA 339181 A CA339181 A CA 339181A CA 1134300 A CA1134300 A CA 1134300A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/84—Compositions based on water or polar solvents
- C09K8/86—Compositions based on water or polar solvents containing organic compounds
- C09K8/88—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
- C09K8/90—Compositions based on water or polar solvents containing organic compounds macromolecular compounds of natural origin, e.g. polysaccharides, cellulose
- C09K8/905—Biopolymers
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- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P19/00—Preparation of compounds containing saccharide radicals
- C12P19/04—Polysaccharides, i.e. compounds containing more than five saccharide radicals attached to each other by glycosidic bonds
- C12P19/06—Xanthan, i.e. Xanthomonas-type heteropolysaccharides
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Abstract
P.C. 6096A
PROCESS FOR TREATING XANTHOMONAS FERMENTATION
BROTH FOR USE IN DISPLACEMENT OF OIL FROM
PARTIALLY DEPLETED RESERVOIRS
Abstract A process for preparing an oil recovery mobility control solution having activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore*filter with a pore size of 1.2 microns which process comprises heating an aqueous solution of Xanthomonas biopolymer at an equivalent xanthan concen-tration of 0.05 to 2.0% and a salt content of less than 0.2% for a period of from about 2 to 60 minutes at a temperature of about 60-98°C, and when the equivalent xanthan concentration exceeds 3000 ppm diluting the solution to an equivalent xanthan concentration of from about 100 to 3000 ppm.
Also disclosed is such a process which comprises the steps of:
(a) diluting a whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating said broth for a period of from about 2 to 60 minutes at a temperature of about 77-98°C; and (c) filtering said broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore*filter with a pore size of 1.2 microns.
*Trade Mark
PROCESS FOR TREATING XANTHOMONAS FERMENTATION
BROTH FOR USE IN DISPLACEMENT OF OIL FROM
PARTIALLY DEPLETED RESERVOIRS
Abstract A process for preparing an oil recovery mobility control solution having activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore*filter with a pore size of 1.2 microns which process comprises heating an aqueous solution of Xanthomonas biopolymer at an equivalent xanthan concen-tration of 0.05 to 2.0% and a salt content of less than 0.2% for a period of from about 2 to 60 minutes at a temperature of about 60-98°C, and when the equivalent xanthan concentration exceeds 3000 ppm diluting the solution to an equivalent xanthan concentration of from about 100 to 3000 ppm.
Also disclosed is such a process which comprises the steps of:
(a) diluting a whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating said broth for a period of from about 2 to 60 minutes at a temperature of about 77-98°C; and (c) filtering said broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore*filter with a pore size of 1.2 microns.
*Trade Mark
Description
3~
P~C. 6096A
PROCES5 FOR TREATING XANT~IOMONAS FERMENT~TION
BROTH FOR IISÆ IN DISP~ACEMENT OF OIL FROM
PARTIALLY DEPLETED_RESERV0 ~S
The hydrophilic colloids produced by Xanthomonas species are polysaccharides which contain mannose, glucose, glucuronic acid, 0-acetyl radicals and acetal-linked pyruvic acid. These gums and their derivatives have found wide food and industrial applioations. Of special interest is the increasing focus on the use of Xanthomonas gums in displacement of oil from partially depleted reservoirs.
Typically, oil is recovered from underground reser-voirs via a series of sequential operations. A new well will senerally produce a limited amount of oil as a result of release of internal pressure in the well.
As this pressure becomes depleted, it is necessary to pump further quantities of oil by mechanical means.
These measures recover only about 25% or less of the total oil stored in the reservoir. A great deal of oil is still trapped within the pores of the ~ormation.
Further enhancement of recovery can then be eff~cted by secondary methods. In one method of recovery, a waterflood is ~arried out by pumping water into a well or series o~ wells, displacing part of the trapped oil from the porous rock and collecting the displa~ed oil - ~3.~
P~C. 6096A
PROCES5 FOR TREATING XANT~IOMONAS FERMENT~TION
BROTH FOR IISÆ IN DISP~ACEMENT OF OIL FROM
PARTIALLY DEPLETED_RESERV0 ~S
The hydrophilic colloids produced by Xanthomonas species are polysaccharides which contain mannose, glucose, glucuronic acid, 0-acetyl radicals and acetal-linked pyruvic acid. These gums and their derivatives have found wide food and industrial applioations. Of special interest is the increasing focus on the use of Xanthomonas gums in displacement of oil from partially depleted reservoirs.
Typically, oil is recovered from underground reser-voirs via a series of sequential operations. A new well will senerally produce a limited amount of oil as a result of release of internal pressure in the well.
As this pressure becomes depleted, it is necessary to pump further quantities of oil by mechanical means.
These measures recover only about 25% or less of the total oil stored in the reservoir. A great deal of oil is still trapped within the pores of the ~ormation.
Further enhancement of recovery can then be eff~cted by secondary methods. In one method of recovery, a waterflood is ~arried out by pumping water into a well or series o~ wells, displacing part of the trapped oil from the porous rock and collecting the displa~ed oil - ~3.~
-2-from surrounding wells. However, waterflooding st.ill leaves about 55-60~ of the available oil trapped in the formation. The e~planation for this is thak the water haæ a very low Vi3C05i ty comp~red to the c~udie oil and teinds to follow the path o~ least resistance, fingering through the oil and leaving large pockets untouched. In addition, surface forces in the forma-tion tend to bind the oil and prevent itsi displacement.
A number of processes have been developed in recent years to recover further quantities of oil from these reservoirs by the use of mobility control 501u-tion~ which enhance oil displacement by increasing the viscosity or permeability of the displacing fluid. Of interest are those enhanced recovery processes employing polymer ~looding with a polysaccharide or polyacrylamide to increase the vi~cosity of the displacing fluid.
Varia~ions of this process include the use of surfactants and co-surfactants to release the oil from the rock formation. Polyacrylamides have been found to suffer such deficiencies as visco~ity loss in brines and severe shear sensitivity. Since, as was well documented in the prior art, xanthan gum is relatively insensitive to salts (does not precipitate or lose v~scosity under normal conditions), is shear stable, thermostable and viscosity stable over i~ wide p~ range, xanthan gum is a good displacing agent. Moreover, the gum is poorly adsorbed on the elements of the porous rock formations and it yives viscosities useful in enhanced oil recovery (5 to 90 centipoise units at 1.32 sec. 1 shear rate) at 10~J concentrations (100 to 3000 ppm). The use of solu-tions of xanthan gum or derivatives of xanthan gum for oil recovery is described in U.S. Patents 3,243,000;
A number of processes have been developed in recent years to recover further quantities of oil from these reservoirs by the use of mobility control 501u-tion~ which enhance oil displacement by increasing the viscosity or permeability of the displacing fluid. Of interest are those enhanced recovery processes employing polymer ~looding with a polysaccharide or polyacrylamide to increase the vi~cosity of the displacing fluid.
Varia~ions of this process include the use of surfactants and co-surfactants to release the oil from the rock formation. Polyacrylamides have been found to suffer such deficiencies as visco~ity loss in brines and severe shear sensitivity. Since, as was well documented in the prior art, xanthan gum is relatively insensitive to salts (does not precipitate or lose v~scosity under normal conditions), is shear stable, thermostable and viscosity stable over i~ wide p~ range, xanthan gum is a good displacing agent. Moreover, the gum is poorly adsorbed on the elements of the porous rock formations and it yives viscosities useful in enhanced oil recovery (5 to 90 centipoise units at 1.32 sec. 1 shear rate) at 10~J concentrations (100 to 3000 ppm). The use of solu-tions of xanthan gum or derivatives of xanthan gum for oil recovery is described in U.S. Patents 3,243,000;
3,198,268, 3,532rl66; 3,305,016; 3,251,417; 3~319,606;
3,319,715, 3,373,810; 3,434,542, 3,729~460 and 4,119,546 , .. .,. , ;. ., : : .:
3~3~
It is suggested in U.S. Patent 3,305,016 that aqueous solutions containing heteropolysaccharide in sufici~-n~
q~antity to increase the viscosity be employed as the thickening agent in preparing viscous waterflooding solutions. The polysaccharide may be prepared, separated, purified and then added~ Alternatively, according to this reference, the entire culture after adding a bactericide (e.g., formaldehyde) to kill the bacteria, may be added to the flood water.
It has been found that various hea tr~atments result in enhanced viscosities or filterability of whole and diluted Xanthomonas fermentation broths.
U.S. Patent 3,501,~78 provides ~hat a heat step is carried out prior to the precipitation of xanthan.
Viscosity increases of 1.5 to 3.5 fold are obtained in the h~at-treated broth. ~.S. Patent 3,773,752 describes a process for heating diluted fermentation broth after addition of an alkali metal salt until coagulation occurs and filtering the hot solution preferably after the addition of a coagulating agent such as alum. The process of U.S. Patent 3,801,502 calls for the addition of an alcohol, phenol, ketone or non-ionic surfactant during the heating process. In the process of U.S.
Patent 3,355,447, the heat-treated fermentation broth is diluted, filtered and the xanthan removed by alcohol precipitation.
This invention is concerned with an improved process for preparing an oil reco~ery mobility control solution having activity enhancement of greater than 15 and a filter ra~io of less than 3 through a Millipoxe~
filter with a pore size of 1.2 microns which process .
` ~39~3~
comprises heating an aqueous solution of Xanthomonas biopolymer at an equîvalent xanthan concentration of 0.14 to 1.5 and a salt con-tent of less than 0.2~ for a period of from about 5 to 20 minutes a-t a -temperature of about 80-98C, and when the equivalent xanthan concentration exceeds 3000 ppm diluting the solution to an e~ui-valent xanthan concentration of from about 100 to 3000 ppm, the solution of Xanthomonas biopolymer being substantially free of insoluble matter having a particle size greater than about 3 microns. Preferably said solution is a fermentation broth.
The present invention likewise embraces a process for preparing an oil recovery mobility control solution which comprises the steps of:
(a) diluting a whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating the broth for a period of from about 5 to 20 minutes at a temperature of about 77-98C; and (c) filtering the broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore* filter with a pore size of 1.2 microns or even finer, said broth being substantially free of in~oluble matter having a particle size greater than about 3 microns, and the process being carried out in the absence of an alkali metal hydroxide.
Preferably step (c) is conducted at from 77 to 98~, and preferably also the heat treated solution is diluted to an equivalent xanthan concentration of from about 100 to 3000 ppm when the equivalent xanthan concentration exceeds 3000 ppm.
~ -4-.
;:, .
l3 In all cases final dilution of the heat-treated solution to use concentration, where required, i5 preferably effected with water haviny a salt cvnt~nt of at le~st about 0.6%.
Whereas previously described heat treatments were individually concerned with enhancing either vis~osity or filterability of whole Xanthomona~ fermentation broths, ., _ the present invention is concerned with an integrated process for preparing mobility control solutions charac~
terize~ by each of these desirable properties, i.e.
enhanced viscosity and improved filterability, as well as enhanced injectability and good thermal stability.
Methods are described for treating Xanthomonas biopolymer solutions or broths of two types: those substantially lS ~ree of insolubles having a particle size greater than about 3 microns, and those containing such insolubles.
For solutions of the former type, the process of the invention provides a product suitable for direct injection without filtration, although for use in oil fields of low permeability, filtration may be resorted to. For Xanthomonas pol~mer solutions of the latter type, the ~;
process of the invention includes a fil~ration step.
For purposes of describing the process of the present invention, the following terminology is used. As a measuxe of xanthan activity, solution viscosity in centi-poises is determined at 6 P~PM and 25C using a Brookfield viscometer with UL adaptor, corresponding to a shear rate of 7.3 sec 1. For a given solution, the degree of dilution ~with 500 ppm salt solution, NaCl: CaC12 = 10~
necessarY to ~rield a viscosity of 10 cp. is determined.
With untreated Xanthomonas polymer this viscosity is .
observed at a polymer concentration of 0.05~ (500 ppm).
~.~3~
The dilution factor observed with a given solu~:ion, multiplied by 0.05%~ yields the e~uivalent xankhan concentration of that solution (also termed th~ acti~e Xanthomonas polymer aoncentrAtion).
Injectability (not used interchangeably h~rein with the term filterability) is an important property of mobility control solutions. It is coxrelated with a Millipore test, as described later in detail, a procedure that measures flow rate through a Millipore filter (0.45 to 3.0 micron pore size) as a function of volume under a constant pressure of 40 psig. The filter ratio (F.R~) is the ratio of the time required to collect the fourth 250 ml. of mobility control solution to the time to collect the first 250 ml. of mobility control solution.
A filter ratio of 1.0 indicates that the solution has no plugging tendencies. An acceptable mobility control solution generally has a filter ratio of 1 to 3 (0.45 to 3 micron Millipore filter~, and preferably below 1.7.
The desirable filter ratio and filter pore size for a particular mobility control solution are dependent on the permeability of the subterran~an stratum of the oil field ~or which oil displacement is planned.
Xanthan mobility control solutions may be subjected to subterranean temperatuxes of 80C. or higher. The thermal stability of these solutions is affected by their salt concentrations as well as other factors.
Thermal stability is measured as the viscosity ratio of the diluted broth after 7 days storage at 80C. to that before storage (10 cps)~
Studies of heat treatment of whole Xanthomonas fermentation broths show that the temperature required for achieving enhanced viscosity of whole broth is con~iderably higher than that for diluted broth~
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The wnol~ hroth is far more stable and resistant to ~anthan polymer reconfiguration by heating ~han is diluted broth.
This can be ~plained by the presence of a higher salt concentration (.ionic strength) in the whol~ ~ro~h, as well as by reduced mol~culax mo~ility.
Further st~dies demonstrate that although enhance~
ment of xanthan activity is achieved by heating, heat-treated whole broth does not retain its injectability (measured as filter ratio). The injectability decreases as the heating temperature and holding time are increased.
Further investigations indicated that neither chemical (surfactants, phenols, etc~) nor physical (shear rate) treatments were effective in improving the injectability of heat-treated whole Xanthomonas fermenta-tion broths.
Studi~s leading to the present invention show thatXanthomonas polymer reconfiguration is the main reason for the injectability change on heat treatment.
Xanthomonas polymer configuration i~ dependent upon the trea~ment temperature, time and salt concentrationO
In turn, the configuration determines the viscosity, injectability and thermal stability of the Xanthomonas solutior..
The novelty and ad~ance over the prior art o~ the present invention reside in the findings that (a) - significant enhancement of xanthan activity is obtained by the moderate (60-~8C.) heat treatment ~or a brief period of time, ~rom about 2 to 60 minutes, of a Xanthomonas fermentation broth diluted with deionized water or water of low salinity, (b) that the moderate heat treatment of diluted whole Xanthomona fermentation broth causes minimum Xanthomonas cell deterioration and so does not materially affect the injectability of the mobility control solution and (c3 final dilution of the mobility control solution to use xan-~han concentration with water of high salinity favors thermal stability.
3~
In one preferred embodiment of the present in~en~ion a whole Xant omonas fermentation bro~h subst~tially free of insoluble matter having a par~icle ~iz~ greater than about 3 microns is treated to provide mobility control solutions with favorable filter ratios such as described in U.S. 4,119,546~
Whole Xanthomonas fermentation broth substantially free of insoluble matter having a particle size greater than about 3 microns is diluted to a xanthan concentra-tion of ahout 0.05 to 2% with deionized water or with field water having a salt content below 0.2%. The diluted broth is then heated with agitation at a temp-erature of 60-98C. for about 2 to 60 minutes, pre~erably about 5 20 minutes. The heat-treated broth is then if necessary diluted to use level (lO0 to 3000 ppm xanthan), preferably with water having a salt content of at least about 0.6%. The diluent may also contain other additives such as preservatives, surfactants and scale inhibitors.
Thus, the inte~rated process of the present invention offers a method for preparing mobility control solutions for use in oil recovery having the following practical and economic advantages:
1. Increased xanthan activity.
2. Improved thermal stability ~when salt water is used for use dilution).
3. Elimination of need for Xanthomona cell f~ltration with retention of good injectability.
Mobility control solutions prepared from the whole fermentation broths by the process of the present inven-tion have filter ratios suitable for use in most oil fields.
~ ~ 3~3~
Where subterranean s~rata are highly impervlous, mobility control solutions with low filter ratios (1-3) through finer Millipore~filters l0.45-0.65 micron pore size) must be used. Under such circumstances, mobility control solutions free of Xanthomonas cells and other insoluble matter must be employed.
For this limited alternative process, the fermenta-tion medium can be selected from any of those described in the literature for the production of xanthan. A simple and useful medium containing an extract of distillers' solubles (Stimufla ~ H.iram ~alker), dipotassium hydrogen phosphate, glucose and magnesium sulfate is described in Biotech. & Bioeng., XII, 75-83 (1970~. The whole Xanthomonas fermentation broth is dilu~ed with water having a salt content below 0.2% to a xanthan concentra-tion of 0.05 to 2.0~, preferably 0.14%-1.5%. The pH
is optionally ad~usted to 6.5 with an alkali metal base.
The solution is stirred (preferably using low shear mixin~) until the xanthan i5 uniformly dispersed (approxi-mately l hour). Low sheax mixing gives a higher solutionviscosity after heat treatment than does high shear mixing.
The diluted broth is heated to a temperature of 60-98C., pre~erably 77-g8C, and filtered. A filter aid, e.g., diatomaceous earth (Dicalite Superaid), at a level of about 4 times the xanthan concentration per liter of diluted broth is added with stirring at 77-98C. and the broth filtered through a pressure leaf ~ilter heated during the run to 77-g~C. Total time at the elevated temperature, including filtration time, should be from about 2 to 60 minutes. Filtration can also be done at ambient temperature after holding at the elevated temperature for the time period selected.
` ~343~0 Final dilution to use xanthan concentration (100-3000 ppm) can be made with water, preferably having a salt content of at least about 0.6%. The filtration step may optionally be conducted after final dilution if desired.
Typical sparkling filtrates with doubled viscosities have filter ratios of 1.5 to 2 through a Millipore filter with a pore size of 0.45 micron. In addition, 1000 ml.
of ~illipore filtrate is collected within 20 minutes.
Thus, this alternative process provides mobility control solutions that have enhanced viscosities and that are injectable into the strata of highly impervious oil fields.
Millipore Injectability Test Prepare 1050 ml of S00 ppm xanthan solution in 500 ppm salt solution (10:1 - NaCl:CaC12) as follows:
In a Waring type blender equipped with a rheostat, measure sufficient broth (based on xanthan content) to provide 0.525g. xanthan solids. Dilute 1 to 6 with salt solution. Shear this mixture at 50 volts for 2 minutes.
Dilute in the blender to 1050 ml with salt solution and shear at 50 volts for 1 minute. Use an experi-mental set-up that allows measurement of the flow rate through a Millipore filter disc (47 mm, 0.45-30 microns pore size) as a function of volume under a constant pressure of 40 psig. Use a reservoir that will accomodate at least 1000 ml. filtrate~
Ch~rge the reservoir with 1050 ml of xanthan solution (500 ppm). Set the pressure at 40 psig. Open the valve and start recording filtrate volume vs. time (seconds).
time to collect the 4th 250 ml of solution Fllter ratlo =
time to collect the 1st 250 ml of solution ~, . .
.:
::
.
,: . :
- ~ .
~ 3~3~0 The following examples are provided for illustrative purposes and should not be deemed to limit the invention, the scope of which is defined by the appended claimsO
_ Xanthomonas fermentation broth substantially free of insoluble matter having a particle size greater than about 3 microns may be prepared in the following way:
Cells of Xan~homonas cam~estris NRRL B-1459a from -a YM agar slant are transferred to 300 ml o~ YM broth contained in a 2.8-liter Fernbach flask and shaken on a rotary shaker for about 31 hours at 28C. A 25 ml aliquot `
is transferred to a 2.8-liter Fernbach flask containing 500 ml of a medium of the followin~ composition:
Ingredient Gram/liter Glucose-fructose (Isosweet 100, Corn Products) 10.1 Crude glucose ~Cerelose) 25.7 ~;
NH4NO3 ' 1.0 MgSO4 7~2 0.10 MnS4-H2 0~03 FeSO 47H2O 0.01 AnhydrGus citric acid 1.0 X2HPO4 4.1 KH2PO4 0.69 The Cerelose and Isosweet 100 are dissolved in distilled water and autoclaved separately. The rest of the ingredients are combined, adjusted to pH 6.4 and autoclaved. The separately autoclaved materials are then combined.
A~ter shaking at 28C. for about 33 hours a 200 ml portlon is transferred to a 4-liter mechanically agitated fermentor containing 2 liters ~f the following medium:
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.: : : , :;,. ,:.: . : :. .. :
3 ~ 3~3~
Ingredient Grams/liter Cerelose (autoclave separately) 25.7 Isosweet 100 (autoclave separately~ 10.1 NH4NO3 1.0 g 4 7H2 0.10 MnS4 H2 0-03 FeSO 7H 0 0.01 Anhydrous citric acid 1.0 CaCl 2H O 0.20 Na2 4 2 4 0.70 The sugars dissolved in 30Q ml of water are auto-claved separately. The rest of the ingredients dissolved in 1700 ml of water are autoclaved, and the two solutions then combined. Aeration is at a rate to provide 1.5 millimoles of o~ygen per liter per minute. The fermen-tation is conducted at 30C. for 48 hours during which time the pH of the medium is maintained between 5.9 and 7.5 by the addition of a sodium phosphate buffer made up with tap water. Ethylenediaminetetraacetic acid is also added to the sodium phosphate buffer to prevent the precipitation of calcium phosphate salts. At the end of the fermentation, the viscosity of the broth exceeds 7800 centipoise units at 5.~7 sec. 1 shear rate and the xanthan concentration is above 1.5~.
EXAMPLiE 2 Xanthomonas whole fermentation broths substantially .
free o~ insoluble matter having a particle size greater than about 3 microns were treated by the process of the invention. A portion of each was diluted with deionized water to a xanthan concentration of 0.6% and heated for 5 minutes at 80C. Th heat-treated solutions wexe then further diluted to a viscosity of about 10 cps. and com-pared with similarly diluted samples which were not heat treated~ The test results were as follows: -: ' , ' ` '" ', ` .,.", ', , ' - : .:'`, ~ , .3~3~
-13- :~
Broth Heat 1.2 micron Activity Thermal No. Treatment Filter Ratio Enhancement (c) Stabil_ty 1 (a) - 1.06 - 0.77 1 (a) + 1.07. ~70~ 0.82 1 (b) - _ _ 0.22 2 (b) - 1.01 2 (b) ~ 1.01 +65%
(a) Final dill1kion with 0.6% sodium chloride (b) Final dilution with 500 ppm sodium chloride ~c) Activity enhancement = Ratio of dilution required ~ -to give 10 cps. at 6 RPM on the Brook~ield viscometer after heat treatment to the dilution required to give 10 cps at 6 RPM on the Brook- :
~ield viscometer before heat treatment, multiplied by 100. :
A series of Xanthomonas broths with xanthan concen- :
trations above about 3% were diluted with deionized water to a xanthan concentration of 0.75%, heated for 5 minutes at a temperatuxe of 85C and diluted to lD cps. visco~ity.
The results are summarized as follows:
1.2 micron Activity Broth Number Heat Treatment Filter Ratio Enhancemen~
1 - 1.22 + 1.15 ~56~ ;
2 - 1.12 ~ 1.13 +67 ~:
3 - 1.12 + 1.22 +67
3,319,715, 3,373,810; 3,434,542, 3,729~460 and 4,119,546 , .. .,. , ;. ., : : .:
3~3~
It is suggested in U.S. Patent 3,305,016 that aqueous solutions containing heteropolysaccharide in sufici~-n~
q~antity to increase the viscosity be employed as the thickening agent in preparing viscous waterflooding solutions. The polysaccharide may be prepared, separated, purified and then added~ Alternatively, according to this reference, the entire culture after adding a bactericide (e.g., formaldehyde) to kill the bacteria, may be added to the flood water.
It has been found that various hea tr~atments result in enhanced viscosities or filterability of whole and diluted Xanthomonas fermentation broths.
U.S. Patent 3,501,~78 provides ~hat a heat step is carried out prior to the precipitation of xanthan.
Viscosity increases of 1.5 to 3.5 fold are obtained in the h~at-treated broth. ~.S. Patent 3,773,752 describes a process for heating diluted fermentation broth after addition of an alkali metal salt until coagulation occurs and filtering the hot solution preferably after the addition of a coagulating agent such as alum. The process of U.S. Patent 3,801,502 calls for the addition of an alcohol, phenol, ketone or non-ionic surfactant during the heating process. In the process of U.S.
Patent 3,355,447, the heat-treated fermentation broth is diluted, filtered and the xanthan removed by alcohol precipitation.
This invention is concerned with an improved process for preparing an oil reco~ery mobility control solution having activity enhancement of greater than 15 and a filter ra~io of less than 3 through a Millipoxe~
filter with a pore size of 1.2 microns which process .
` ~39~3~
comprises heating an aqueous solution of Xanthomonas biopolymer at an equîvalent xanthan concentration of 0.14 to 1.5 and a salt con-tent of less than 0.2~ for a period of from about 5 to 20 minutes a-t a -temperature of about 80-98C, and when the equivalent xanthan concentration exceeds 3000 ppm diluting the solution to an e~ui-valent xanthan concentration of from about 100 to 3000 ppm, the solution of Xanthomonas biopolymer being substantially free of insoluble matter having a particle size greater than about 3 microns. Preferably said solution is a fermentation broth.
The present invention likewise embraces a process for preparing an oil recovery mobility control solution which comprises the steps of:
(a) diluting a whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating the broth for a period of from about 5 to 20 minutes at a temperature of about 77-98C; and (c) filtering the broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore* filter with a pore size of 1.2 microns or even finer, said broth being substantially free of in~oluble matter having a particle size greater than about 3 microns, and the process being carried out in the absence of an alkali metal hydroxide.
Preferably step (c) is conducted at from 77 to 98~, and preferably also the heat treated solution is diluted to an equivalent xanthan concentration of from about 100 to 3000 ppm when the equivalent xanthan concentration exceeds 3000 ppm.
~ -4-.
;:, .
l3 In all cases final dilution of the heat-treated solution to use concentration, where required, i5 preferably effected with water haviny a salt cvnt~nt of at le~st about 0.6%.
Whereas previously described heat treatments were individually concerned with enhancing either vis~osity or filterability of whole Xanthomona~ fermentation broths, ., _ the present invention is concerned with an integrated process for preparing mobility control solutions charac~
terize~ by each of these desirable properties, i.e.
enhanced viscosity and improved filterability, as well as enhanced injectability and good thermal stability.
Methods are described for treating Xanthomonas biopolymer solutions or broths of two types: those substantially lS ~ree of insolubles having a particle size greater than about 3 microns, and those containing such insolubles.
For solutions of the former type, the process of the invention provides a product suitable for direct injection without filtration, although for use in oil fields of low permeability, filtration may be resorted to. For Xanthomonas pol~mer solutions of the latter type, the ~;
process of the invention includes a fil~ration step.
For purposes of describing the process of the present invention, the following terminology is used. As a measuxe of xanthan activity, solution viscosity in centi-poises is determined at 6 P~PM and 25C using a Brookfield viscometer with UL adaptor, corresponding to a shear rate of 7.3 sec 1. For a given solution, the degree of dilution ~with 500 ppm salt solution, NaCl: CaC12 = 10~
necessarY to ~rield a viscosity of 10 cp. is determined.
With untreated Xanthomonas polymer this viscosity is .
observed at a polymer concentration of 0.05~ (500 ppm).
~.~3~
The dilution factor observed with a given solu~:ion, multiplied by 0.05%~ yields the e~uivalent xankhan concentration of that solution (also termed th~ acti~e Xanthomonas polymer aoncentrAtion).
Injectability (not used interchangeably h~rein with the term filterability) is an important property of mobility control solutions. It is coxrelated with a Millipore test, as described later in detail, a procedure that measures flow rate through a Millipore filter (0.45 to 3.0 micron pore size) as a function of volume under a constant pressure of 40 psig. The filter ratio (F.R~) is the ratio of the time required to collect the fourth 250 ml. of mobility control solution to the time to collect the first 250 ml. of mobility control solution.
A filter ratio of 1.0 indicates that the solution has no plugging tendencies. An acceptable mobility control solution generally has a filter ratio of 1 to 3 (0.45 to 3 micron Millipore filter~, and preferably below 1.7.
The desirable filter ratio and filter pore size for a particular mobility control solution are dependent on the permeability of the subterran~an stratum of the oil field ~or which oil displacement is planned.
Xanthan mobility control solutions may be subjected to subterranean temperatuxes of 80C. or higher. The thermal stability of these solutions is affected by their salt concentrations as well as other factors.
Thermal stability is measured as the viscosity ratio of the diluted broth after 7 days storage at 80C. to that before storage (10 cps)~
Studies of heat treatment of whole Xanthomonas fermentation broths show that the temperature required for achieving enhanced viscosity of whole broth is con~iderably higher than that for diluted broth~
~, .. .
.3~
The wnol~ hroth is far more stable and resistant to ~anthan polymer reconfiguration by heating ~han is diluted broth.
This can be ~plained by the presence of a higher salt concentration (.ionic strength) in the whol~ ~ro~h, as well as by reduced mol~culax mo~ility.
Further st~dies demonstrate that although enhance~
ment of xanthan activity is achieved by heating, heat-treated whole broth does not retain its injectability (measured as filter ratio). The injectability decreases as the heating temperature and holding time are increased.
Further investigations indicated that neither chemical (surfactants, phenols, etc~) nor physical (shear rate) treatments were effective in improving the injectability of heat-treated whole Xanthomonas fermenta-tion broths.
Studi~s leading to the present invention show thatXanthomonas polymer reconfiguration is the main reason for the injectability change on heat treatment.
Xanthomonas polymer configuration i~ dependent upon the trea~ment temperature, time and salt concentrationO
In turn, the configuration determines the viscosity, injectability and thermal stability of the Xanthomonas solutior..
The novelty and ad~ance over the prior art o~ the present invention reside in the findings that (a) - significant enhancement of xanthan activity is obtained by the moderate (60-~8C.) heat treatment ~or a brief period of time, ~rom about 2 to 60 minutes, of a Xanthomonas fermentation broth diluted with deionized water or water of low salinity, (b) that the moderate heat treatment of diluted whole Xanthomona fermentation broth causes minimum Xanthomonas cell deterioration and so does not materially affect the injectability of the mobility control solution and (c3 final dilution of the mobility control solution to use xan-~han concentration with water of high salinity favors thermal stability.
3~
In one preferred embodiment of the present in~en~ion a whole Xant omonas fermentation bro~h subst~tially free of insoluble matter having a par~icle ~iz~ greater than about 3 microns is treated to provide mobility control solutions with favorable filter ratios such as described in U.S. 4,119,546~
Whole Xanthomonas fermentation broth substantially free of insoluble matter having a particle size greater than about 3 microns is diluted to a xanthan concentra-tion of ahout 0.05 to 2% with deionized water or with field water having a salt content below 0.2%. The diluted broth is then heated with agitation at a temp-erature of 60-98C. for about 2 to 60 minutes, pre~erably about 5 20 minutes. The heat-treated broth is then if necessary diluted to use level (lO0 to 3000 ppm xanthan), preferably with water having a salt content of at least about 0.6%. The diluent may also contain other additives such as preservatives, surfactants and scale inhibitors.
Thus, the inte~rated process of the present invention offers a method for preparing mobility control solutions for use in oil recovery having the following practical and economic advantages:
1. Increased xanthan activity.
2. Improved thermal stability ~when salt water is used for use dilution).
3. Elimination of need for Xanthomona cell f~ltration with retention of good injectability.
Mobility control solutions prepared from the whole fermentation broths by the process of the present inven-tion have filter ratios suitable for use in most oil fields.
~ ~ 3~3~
Where subterranean s~rata are highly impervlous, mobility control solutions with low filter ratios (1-3) through finer Millipore~filters l0.45-0.65 micron pore size) must be used. Under such circumstances, mobility control solutions free of Xanthomonas cells and other insoluble matter must be employed.
For this limited alternative process, the fermenta-tion medium can be selected from any of those described in the literature for the production of xanthan. A simple and useful medium containing an extract of distillers' solubles (Stimufla ~ H.iram ~alker), dipotassium hydrogen phosphate, glucose and magnesium sulfate is described in Biotech. & Bioeng., XII, 75-83 (1970~. The whole Xanthomonas fermentation broth is dilu~ed with water having a salt content below 0.2% to a xanthan concentra-tion of 0.05 to 2.0~, preferably 0.14%-1.5%. The pH
is optionally ad~usted to 6.5 with an alkali metal base.
The solution is stirred (preferably using low shear mixin~) until the xanthan i5 uniformly dispersed (approxi-mately l hour). Low sheax mixing gives a higher solutionviscosity after heat treatment than does high shear mixing.
The diluted broth is heated to a temperature of 60-98C., pre~erably 77-g8C, and filtered. A filter aid, e.g., diatomaceous earth (Dicalite Superaid), at a level of about 4 times the xanthan concentration per liter of diluted broth is added with stirring at 77-98C. and the broth filtered through a pressure leaf ~ilter heated during the run to 77-g~C. Total time at the elevated temperature, including filtration time, should be from about 2 to 60 minutes. Filtration can also be done at ambient temperature after holding at the elevated temperature for the time period selected.
` ~343~0 Final dilution to use xanthan concentration (100-3000 ppm) can be made with water, preferably having a salt content of at least about 0.6%. The filtration step may optionally be conducted after final dilution if desired.
Typical sparkling filtrates with doubled viscosities have filter ratios of 1.5 to 2 through a Millipore filter with a pore size of 0.45 micron. In addition, 1000 ml.
of ~illipore filtrate is collected within 20 minutes.
Thus, this alternative process provides mobility control solutions that have enhanced viscosities and that are injectable into the strata of highly impervious oil fields.
Millipore Injectability Test Prepare 1050 ml of S00 ppm xanthan solution in 500 ppm salt solution (10:1 - NaCl:CaC12) as follows:
In a Waring type blender equipped with a rheostat, measure sufficient broth (based on xanthan content) to provide 0.525g. xanthan solids. Dilute 1 to 6 with salt solution. Shear this mixture at 50 volts for 2 minutes.
Dilute in the blender to 1050 ml with salt solution and shear at 50 volts for 1 minute. Use an experi-mental set-up that allows measurement of the flow rate through a Millipore filter disc (47 mm, 0.45-30 microns pore size) as a function of volume under a constant pressure of 40 psig. Use a reservoir that will accomodate at least 1000 ml. filtrate~
Ch~rge the reservoir with 1050 ml of xanthan solution (500 ppm). Set the pressure at 40 psig. Open the valve and start recording filtrate volume vs. time (seconds).
time to collect the 4th 250 ml of solution Fllter ratlo =
time to collect the 1st 250 ml of solution ~, . .
.:
::
.
,: . :
- ~ .
~ 3~3~0 The following examples are provided for illustrative purposes and should not be deemed to limit the invention, the scope of which is defined by the appended claimsO
_ Xanthomonas fermentation broth substantially free of insoluble matter having a particle size greater than about 3 microns may be prepared in the following way:
Cells of Xan~homonas cam~estris NRRL B-1459a from -a YM agar slant are transferred to 300 ml o~ YM broth contained in a 2.8-liter Fernbach flask and shaken on a rotary shaker for about 31 hours at 28C. A 25 ml aliquot `
is transferred to a 2.8-liter Fernbach flask containing 500 ml of a medium of the followin~ composition:
Ingredient Gram/liter Glucose-fructose (Isosweet 100, Corn Products) 10.1 Crude glucose ~Cerelose) 25.7 ~;
NH4NO3 ' 1.0 MgSO4 7~2 0.10 MnS4-H2 0~03 FeSO 47H2O 0.01 AnhydrGus citric acid 1.0 X2HPO4 4.1 KH2PO4 0.69 The Cerelose and Isosweet 100 are dissolved in distilled water and autoclaved separately. The rest of the ingredients are combined, adjusted to pH 6.4 and autoclaved. The separately autoclaved materials are then combined.
A~ter shaking at 28C. for about 33 hours a 200 ml portlon is transferred to a 4-liter mechanically agitated fermentor containing 2 liters ~f the following medium:
: ,: :: . :, . :,, . : ::, : . : ; :
.: : : , :;,. ,:.: . : :. .. :
3 ~ 3~3~
Ingredient Grams/liter Cerelose (autoclave separately) 25.7 Isosweet 100 (autoclave separately~ 10.1 NH4NO3 1.0 g 4 7H2 0.10 MnS4 H2 0-03 FeSO 7H 0 0.01 Anhydrous citric acid 1.0 CaCl 2H O 0.20 Na2 4 2 4 0.70 The sugars dissolved in 30Q ml of water are auto-claved separately. The rest of the ingredients dissolved in 1700 ml of water are autoclaved, and the two solutions then combined. Aeration is at a rate to provide 1.5 millimoles of o~ygen per liter per minute. The fermen-tation is conducted at 30C. for 48 hours during which time the pH of the medium is maintained between 5.9 and 7.5 by the addition of a sodium phosphate buffer made up with tap water. Ethylenediaminetetraacetic acid is also added to the sodium phosphate buffer to prevent the precipitation of calcium phosphate salts. At the end of the fermentation, the viscosity of the broth exceeds 7800 centipoise units at 5.~7 sec. 1 shear rate and the xanthan concentration is above 1.5~.
EXAMPLiE 2 Xanthomonas whole fermentation broths substantially .
free o~ insoluble matter having a particle size greater than about 3 microns were treated by the process of the invention. A portion of each was diluted with deionized water to a xanthan concentration of 0.6% and heated for 5 minutes at 80C. Th heat-treated solutions wexe then further diluted to a viscosity of about 10 cps. and com-pared with similarly diluted samples which were not heat treated~ The test results were as follows: -: ' , ' ` '" ', ` .,.", ', , ' - : .:'`, ~ , .3~3~
-13- :~
Broth Heat 1.2 micron Activity Thermal No. Treatment Filter Ratio Enhancement (c) Stabil_ty 1 (a) - 1.06 - 0.77 1 (a) + 1.07. ~70~ 0.82 1 (b) - _ _ 0.22 2 (b) - 1.01 2 (b) ~ 1.01 +65%
(a) Final dill1kion with 0.6% sodium chloride (b) Final dilution with 500 ppm sodium chloride ~c) Activity enhancement = Ratio of dilution required ~ -to give 10 cps. at 6 RPM on the Brook~ield viscometer after heat treatment to the dilution required to give 10 cps at 6 RPM on the Brook- :
~ield viscometer before heat treatment, multiplied by 100. :
A series of Xanthomonas broths with xanthan concen- :
trations above about 3% were diluted with deionized water to a xanthan concentration of 0.75%, heated for 5 minutes at a temperatuxe of 85C and diluted to lD cps. visco~ity.
The results are summarized as follows:
1.2 micron Activity Broth Number Heat Treatment Filter Ratio Enhancemen~
1 - 1.22 + 1.15 ~56~ ;
2 - 1.12 ~ 1.13 +67 ~:
3 - 1.12 + 1.22 +67
4 - 1~12 + 1.07 +67 - 1.16 + 1.08 +67 - 1.27 + 1.16 +57 .
~:
~ ~ ~3~3~
1.~ micron Activity Broth Number ~eat Treatment Filter Ratio Enhancement 7 - 1.21 + 1.11 l67%
8 - 1.22 + 1.09 ~4 9 - 2.11 ~ 1.31 ~67 - 1.28 ~ 1.10 +67 11 1.37 ~ l.OS ~84 12 - 1.13 + 1.04 ~78 Averaye - 1.28 ~ 1013 ~70 , ~ sample of whole Xanthomonas fermentation broth having an initial 0.65 micron FR of 2.59 was treated using the invention to improve its viscosi~y and mobility r ;
characteristics. A 1% solution of xanthan in 500 ppm salt solution (10:1 Na:Ca) was heated to 85C. for 5 minutes, then cooled to room temperature, diluted to 0.14% using the same salt solution, 5600 ppm diatomaceous earth bodyaid was added, and the heat-treated diluted solu-tion was filtered at room temperature on a precoated pressure leaf filter. The sparkling filtrate exhibited a 40% activity enhancement and an improved 1.71 filter ratio at 0.65 microns filter pore size.
~343~
-15- ~, ,~
A sample of whole Xanthomonas fermentation broth -which initially plugged a 0.45 micron Millipore filter, was treated to improve its viscosity and injectivity characteristics. The broth was diluted ~o 1% with 500 ppm salt solution, heated to 85C and then diluted to 0.14%
by adding 500 ppm salt solution at 85C. containing sufficient diatomaceous eaxth bodyaid to s~eed ~ubse-quent filtrations. The heat-treated solutien was then filtered on a precoated pressure leaf filter at about 85C. and a flux of 13.1 gal/hr ft2 obtained. Total time at 85C. was about 20 minutes. The sparkling filtrate exhibited an activity enhancement in excess of 18~i and improved injectivity as demonstrated by Millipore filter ratios of 1.94 at 0.45 micron and 1.23 15 at 0.65 micron pore size. `
Xanthomonas fermentation broth containing insoluble matter having a particle size greater than 3 microns may be prepared in the following way:
Cells of Xanthomonas campestris NRRL B-1459a from a YM agar sfant are transferred to 300 ml of YM Broth contained in a 2.8 liter Fexnbach flask and shaken on a rotary shaker for about 31 hours at 28C. A 25 ml aliquot is transferred to a 2.8 liter Fernbach flask containing 500 ml of a medium of the following composition:
Ing'redie'nt Grams/100 ~rams Part A
*Distillers' soluble extract 18 2EIP4 0.5 Antifoam (GE 60) 0.08 Distilled water 57 p~ ~.1 Autoclave separately `
,.
Grams~100 grams Part B
G1UCOSQ 2.5 MgSO4 0.01 Distilled water 2 p~ 4.~5 * The extract is prepared by boiling a 10~ w/w aqueous slurry of distillers' dried solubles for 5 minutes, cooling, making up evaporation losses with fresh water, adding 4% diatomaceous filter aid, and vacuum filtering.
After shaking at 28C. for about 33 hours, a 200 ~1 portion is transferred to a 4-liter mechanically agitated fermen~or containing 2 liters of the above medium.
Aeration is at a rate to provide 1.5 to 3.5 millimoles of oxygen per liter per minute. The fermentation is conducted at 30C. until the level of reducing sugar is 0.3% and a viscosity of at least 4500 centipoise units and a xanthan concentration of at least 1.0~ is obtainedO
Treatment of the Xanthomonas fermentation broth by the present process is illustrated by the following:
The whole brcth is diluted to 750 ppm xanthan with water containing 500 ppm sod~ium chloride and calcium chloride in a 10:1 ratio. The diluted broth is stirred for about an hour using low shear mixing until the xanthan is uniformly dispersed and is then heated for about 5 minutes at a temperature of about 95 4C ~ Dicalite Superaid ~3 grams p~r liter of diluted broth) is stirred in at a temperature of about 95C. and the broth filtered through a vertical leaf test filter with a cotton duck , . .
~' cloth filter medium and no precoat. The filter area is 0O025 square feet. The filter is heated with an electric tape before and during the run to 93-98C. :~
The filtration is done at a constant pressure of 40 psi. The first filtrate is recycled until it becomes clear. The filtrate is cooled to 20-30C.
This treatment ~ill typically yield a filtrate having ~:
a viscosity of about 30 cps~ and a filter ratio below 2 thorugh Millipore filters with pore sizes of 0.45 :
and 1.2 microns.
~:
~ ~ ~3~3~
1.~ micron Activity Broth Number ~eat Treatment Filter Ratio Enhancement 7 - 1.21 + 1.11 l67%
8 - 1.22 + 1.09 ~4 9 - 2.11 ~ 1.31 ~67 - 1.28 ~ 1.10 +67 11 1.37 ~ l.OS ~84 12 - 1.13 + 1.04 ~78 Averaye - 1.28 ~ 1013 ~70 , ~ sample of whole Xanthomonas fermentation broth having an initial 0.65 micron FR of 2.59 was treated using the invention to improve its viscosi~y and mobility r ;
characteristics. A 1% solution of xanthan in 500 ppm salt solution (10:1 Na:Ca) was heated to 85C. for 5 minutes, then cooled to room temperature, diluted to 0.14% using the same salt solution, 5600 ppm diatomaceous earth bodyaid was added, and the heat-treated diluted solu-tion was filtered at room temperature on a precoated pressure leaf filter. The sparkling filtrate exhibited a 40% activity enhancement and an improved 1.71 filter ratio at 0.65 microns filter pore size.
~343~
-15- ~, ,~
A sample of whole Xanthomonas fermentation broth -which initially plugged a 0.45 micron Millipore filter, was treated to improve its viscosity and injectivity characteristics. The broth was diluted ~o 1% with 500 ppm salt solution, heated to 85C and then diluted to 0.14%
by adding 500 ppm salt solution at 85C. containing sufficient diatomaceous eaxth bodyaid to s~eed ~ubse-quent filtrations. The heat-treated solutien was then filtered on a precoated pressure leaf filter at about 85C. and a flux of 13.1 gal/hr ft2 obtained. Total time at 85C. was about 20 minutes. The sparkling filtrate exhibited an activity enhancement in excess of 18~i and improved injectivity as demonstrated by Millipore filter ratios of 1.94 at 0.45 micron and 1.23 15 at 0.65 micron pore size. `
Xanthomonas fermentation broth containing insoluble matter having a particle size greater than 3 microns may be prepared in the following way:
Cells of Xanthomonas campestris NRRL B-1459a from a YM agar sfant are transferred to 300 ml of YM Broth contained in a 2.8 liter Fexnbach flask and shaken on a rotary shaker for about 31 hours at 28C. A 25 ml aliquot is transferred to a 2.8 liter Fernbach flask containing 500 ml of a medium of the following composition:
Ing'redie'nt Grams/100 ~rams Part A
*Distillers' soluble extract 18 2EIP4 0.5 Antifoam (GE 60) 0.08 Distilled water 57 p~ ~.1 Autoclave separately `
,.
Grams~100 grams Part B
G1UCOSQ 2.5 MgSO4 0.01 Distilled water 2 p~ 4.~5 * The extract is prepared by boiling a 10~ w/w aqueous slurry of distillers' dried solubles for 5 minutes, cooling, making up evaporation losses with fresh water, adding 4% diatomaceous filter aid, and vacuum filtering.
After shaking at 28C. for about 33 hours, a 200 ~1 portion is transferred to a 4-liter mechanically agitated fermen~or containing 2 liters of the above medium.
Aeration is at a rate to provide 1.5 to 3.5 millimoles of oxygen per liter per minute. The fermentation is conducted at 30C. until the level of reducing sugar is 0.3% and a viscosity of at least 4500 centipoise units and a xanthan concentration of at least 1.0~ is obtainedO
Treatment of the Xanthomonas fermentation broth by the present process is illustrated by the following:
The whole brcth is diluted to 750 ppm xanthan with water containing 500 ppm sod~ium chloride and calcium chloride in a 10:1 ratio. The diluted broth is stirred for about an hour using low shear mixing until the xanthan is uniformly dispersed and is then heated for about 5 minutes at a temperature of about 95 4C ~ Dicalite Superaid ~3 grams p~r liter of diluted broth) is stirred in at a temperature of about 95C. and the broth filtered through a vertical leaf test filter with a cotton duck , . .
~' cloth filter medium and no precoat. The filter area is 0O025 square feet. The filter is heated with an electric tape before and during the run to 93-98C. :~
The filtration is done at a constant pressure of 40 psi. The first filtrate is recycled until it becomes clear. The filtrate is cooled to 20-30C.
This treatment ~ill typically yield a filtrate having ~:
a viscosity of about 30 cps~ and a filter ratio below 2 thorugh Millipore filters with pore sizes of 0.45 :
and 1.2 microns.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for preparing an oil recovery mobility control solution having activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore* filter with a pore size of 1.2 microns which process comprises heating an aqueous solution of Xanthomonas biopolymer at an equivalent xanthan concentration of 0.14 to 1.5% and a salt content of less than 0.2% for a period of from about 5 to 20 minutes at a temperature of about 80-98°C., and when the equivalent xanthan concentration exceeds 3000 ppm diluting the solution to an equivalent xanthan concentration of from about 100 to 3000ppm, said solution of Xanthomonas biopolymer being substantially free of insoluble matter having a particle size greater than about 3 microns.
2. The process of claim 1 wherein said solution of Xanthomonas biopolymer is a fermentation broth.
3. The process of claim 1 wherein said dilution is effected with water having a salt content of at least about 0.6%.
4. A process for preparing an oil recovery mobility control solution which comprises the steps of:
(a) diluting whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating said broth for a period of from about 5 to 20 minutes at a temperature of about 77-98°C; and (c) filtering said broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore* filter with pore size of 1.2 microns, said whole fermentation broth being substantially free of insoluble matter having a particle size greater than about 3 microns, and the process being carried out in the absence of an alkali metal hydroxide.
(a) diluting whole Xanthomonas fermentation broth to an equivalent xanthan concentration of 0.14-1.5% with water having a salt content of less than 0.2%;
(b) heating said broth for a period of from about 5 to 20 minutes at a temperature of about 77-98°C; and (c) filtering said broth to yield a filtrate with activity enhancement of greater than 15% and a filter ratio of less than 3 through a Millipore* filter with pore size of 1.2 microns, said whole fermentation broth being substantially free of insoluble matter having a particle size greater than about 3 microns, and the process being carried out in the absence of an alkali metal hydroxide.
5. The process of claim 4 wherein step (c) is carried out at a temperature of from 77 to 98°C.
6. The process of claim 4 wherein the heat-treated solution is diluted to an equivalent xanthan concentration of from about 100 to 3000 ppm when the equivalent xanthan concentration exceeds 3000 ppm.
7. The process of claim 6 wherein the dilution of said heat-treated solution is effected with water having a salt content of at least about 0.6%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95789578A | 1978-11-06 | 1978-11-06 | |
| US957,895 | 1978-11-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1134300A true CA1134300A (en) | 1982-10-26 |
Family
ID=25500314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA339,181A Expired CA1134300A (en) | 1978-11-06 | 1979-11-05 | Process for treating xanthomonas fermentation broth for use in displacement of oil from partially depleted reservoirs |
Country Status (12)
| Country | Link |
|---|---|
| BR (1) | BR7907164A (en) |
| CA (1) | CA1134300A (en) |
| DE (1) | DE2944634C2 (en) |
| EG (1) | EG14372A (en) |
| ES (1) | ES485743A1 (en) |
| FR (1) | FR2440992A1 (en) |
| GB (1) | GB2036056B (en) |
| IE (1) | IE48744B1 (en) |
| IL (1) | IL58633A (en) |
| IT (1) | IT1126314B (en) |
| NL (1) | NL7907884A (en) |
| NO (1) | NO148866C (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4425246A (en) | 1981-09-18 | 1984-01-10 | Exxon Research & Engineering Co. | Oil recovery using stabilized saline heat-treated heteropolysaccharide solutions |
| GB8428348D0 (en) * | 1984-11-09 | 1984-12-19 | Shell Int Research | Degrading of viscous microbial polysaccharide formulation |
| FR2600664B1 (en) * | 1986-06-27 | 1988-09-23 | Schlumberger Cie Dowell | PROCESS FOR IMPROVING THE PHYSICO-CHEMICAL PROPERTIES OF POLYMER SOLUTIONS USED IN OIL SERVICES |
| CN115873570B (en) * | 2021-09-27 | 2024-02-02 | 中国石油化工股份有限公司 | Microbial oil extraction profile control agent and application thereof |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3355447A (en) * | 1964-04-28 | 1967-11-28 | Kelco Co | Treatment of xanthomonas hydrophilic colloid and resulting product |
| FR1575756A (en) * | 1968-04-29 | 1969-07-25 | ||
| US3773752A (en) * | 1971-02-25 | 1973-11-20 | Phillips Petroleum Co | Recovery of microbial polysaccharides |
| US3966618A (en) * | 1974-03-11 | 1976-06-29 | Merck & Co., Inc. | Clarification of xanthan gum |
| US4010071A (en) * | 1974-10-10 | 1977-03-01 | Merck & Co., Inc. | Clarification of xanthan gum |
| CA1073384A (en) * | 1975-07-23 | 1980-03-11 | Kenneth S. Kang | Enhancement of viscosity imparting properties of xanthan gum |
| CA1070629A (en) * | 1975-11-10 | 1980-01-29 | Allen I. Laskin | Process for modifying biopolymers |
| US4119546A (en) * | 1976-08-05 | 1978-10-10 | Pfizer Inc. | Process for producing Xanthomonas hydrophilic colloid, product resulting therefrom, and use thereof in displacement of oil from partially depleted reservoirs |
| NO150965C (en) * | 1976-08-05 | 1985-01-16 | Pfizer | PROCEDURE FOR PREPARING A XANTAN SOLUTION |
| JPS5366496A (en) * | 1976-11-22 | 1978-06-13 | Merck & Co Inc | Rapidly dispersible vegetable gum |
-
1979
- 1979-10-26 NL NL7907884A patent/NL7907884A/en not_active Application Discontinuation
- 1979-10-29 EG EG665/79A patent/EG14372A/en active
- 1979-10-31 GB GB7937783A patent/GB2036056B/en not_active Expired
- 1979-11-05 CA CA339,181A patent/CA1134300A/en not_active Expired
- 1979-11-05 DE DE2944634A patent/DE2944634C2/en not_active Expired
- 1979-11-05 IE IE2114/79A patent/IE48744B1/en not_active IP Right Cessation
- 1979-11-05 NO NO793561A patent/NO148866C/en unknown
- 1979-11-05 FR FR7927190A patent/FR2440992A1/en active Granted
- 1979-11-05 IL IL58633A patent/IL58633A/en unknown
- 1979-11-05 BR BR7907164A patent/BR7907164A/en not_active IP Right Cessation
- 1979-11-05 IT IT27040/79A patent/IT1126314B/en active
- 1979-11-06 ES ES485743A patent/ES485743A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2944634A1 (en) | 1980-05-14 |
| BR7907164A (en) | 1980-10-21 |
| ES485743A1 (en) | 1980-10-01 |
| IT1126314B (en) | 1986-05-21 |
| NO148866B (en) | 1983-09-19 |
| EG14372A (en) | 1984-03-31 |
| IL58633A0 (en) | 1980-02-29 |
| NO793561L (en) | 1980-05-07 |
| NO148866C (en) | 1983-12-28 |
| NL7907884A (en) | 1980-05-08 |
| IT7927040A0 (en) | 1979-11-05 |
| DE2944634C2 (en) | 1983-06-30 |
| IL58633A (en) | 1982-08-31 |
| GB2036056B (en) | 1983-04-13 |
| IE792114L (en) | 1980-05-06 |
| GB2036056A (en) | 1980-06-25 |
| FR2440992B1 (en) | 1985-05-24 |
| FR2440992A1 (en) | 1980-06-06 |
| IE48744B1 (en) | 1985-05-01 |
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