US4412925A — Assisted oil recovery with use of fermentation fl…

Claim 1

Independent Claim 147 words

An aqueous composition suitable for direct use in waterflood oil recovery processes, which comprises a clarified and stabilized fermentation fluid containing at least one bactericidal agent, said clarified and stabilized fermentation fluid being obtained by a process consisting essentially of the steps of: (a) culturing a polysaccharide-producing microorganism in an aqueous culture medium to produce an aqueous culture containing dissolved polysaccharide therein; and (b) clarifying and stabilizing the resultant aqueous culture from step (a), the clarification being effected by at least one of centrifugation and filtration, and the stabilization being effected by introducing therein at least one bactericidal agent, and recovering the resultant clarified and stabilized fermentation fluid containing said at least one bactericidal agent; whereby said aqueous composition is obtained without precipitation and recovery of a solid polysaccharide and dissolution thereof in an aqueous medium and is suitable for direct use in waterflood oil recovery processes.

Claim 2

Dependent Claim 147 words

An aqueous composition suitable for direct use in waterflood oil recovery processes, which comprises a clarified and stabilized fermentation fluid containing at least one bactericidal agent, said clarified and stabilized fermentation fluid being obtained by a process consisting essentially of the steps of: (a) culturing a polysaccharide-producing microorganism in an aqueous culture medium to produce an aqueous culture containing dissolved polysaccharide therein; and (b) clarifying and stabilizing the resultant aqueous culture from step (a), the clarification being effected by at least one of centrifugation and filtration, and the stabilization being effected by introducing therein at least one bactericidal agent, and recovering the resultant clarified and stabilized fermentation fluid containing said at least one bactericidal agent; whereby said aqueous composition is obtained without precipitation and recovery of a solid polysaccharide and dissolution thereof in an aqueous medium and is suitable for direct use in waterflood oil recovery processes.

Claim 3

Dependent Claim 13 words

A composition according to claim 1, wherein the bactericidal agent is sodium azide.

Claim 4

Dependent Claim 28 words

A composition according to claim 2, wherein sodium azide is used in an amount of 10 to 2,000 parts per million by weight of the clarified fermentation fluid.

Claim 5

Dependent Claim 19 words

A composition according to claim 1, wherein the clarification treatment is effected by centrifugation at at least 4,000 g.

Claim 6

Dependent Claim 17 words

A composition according to claim 1, wherein the polysaccharide-producing microorganism is a microorganism of the Xanthomonas type.

Claim 7

Dependent Claim 30 words

A composition according to claim 1, which has a polysaccharide concentration of 0.005 to 1% by weight and a viscosity of from 2 to 30 centipoises at the reservoir temperature.

Claim 8

Dependent Claim 17 words

A composition according to claim 1, wherein the bactericidal agent is a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one.

Claim 9

Dependent Claim 23 words

A composition according to claim 7, wherein said mixture is used in an amount of 10 to 1,000 parts per million by weight.

Claim 10

Dependent Claim 12 words

A composition according to claim 5, wherein the microorganism is Xanthomonas campestris.

Claim 11

Dependent Claim 36 words

A composition according to claim 1, wherein the clarification treatment is effected by centrifugation at from 6,000 to 60,000 g, followed by passage through at least one 3μ filter, and thereafter passage through a 0.8μ filter.

Claim 12

Dependent Claim 20 words

A composition according to claim 1, wherein the clarification treatment is effected by passage through a bed of diatomaceous earth.

Claim 13

Dependent Claim 28 words

A composition according to claim 1, wherein the clarification treatment is effected by passage through a filter whose pores have an average diameter of at most 3 microns.

Claim 14

Dependent Claim 177 words

In a method for the assisted recovery of oil from an underground oil containing formation, wherein an aqueous polysaccharide solution is flooded through the formation and oil is recovered from said formation; the improvement comprising employing as said aqueous polysaccharide solution a composition comprising a clarified and stabilized fermentation fluid containing at least one bactericidal agent, said clarified and stabilized fermentation fluid being obtained by a process consisting essentially of the steps of: (a) culturing a polysaccharide-producing microorganism in an aqueous culture medium to produce an aqueous culture containing dissolved polysaccharide therein; and (b) clarifying and stabilizing the resultant aqueous culture from step (a), the clarification being effected by at least one of centrifugation and filtration, and the stabilization being effected by introducing therein at least one bactericidal agent, and recovering the resultant clarified and stabilized fermentation fluid containing said at least one bactericidal agent; whereby said aqueous composition is obtained without precipitation and recovery of a solid polysaccharide and dissolution thereof in an aqueous medium and is suitable for direct use in waterflood oil recovery processes.

Claim 15

Dependent Claim 177 words

In a method for the assisted recovery of oil from an underground oil containing formation, wherein an aqueous polysaccharide solution is flooded through the formation and oil is recovered from said formation; the improvement comprising employing as said aqueous polysaccharide solution a composition comprising a clarified and stabilized fermentation fluid containing at least one bactericidal agent, said clarified and stabilized fermentation fluid being obtained by a process consisting essentially of the steps of: (a) culturing a polysaccharide-producing microorganism in an aqueous culture medium to produce an aqueous culture containing dissolved polysaccharide therein; and (b) clarifying and stabilizing the resultant aqueous culture from step (a), the clarification being effected by at least one of centrifugation and filtration, and the stabilization being effected by introducing therein at least one bactericidal agent, and recovering the resultant clarified and stabilized fermentation fluid containing said at least one bactericidal agent; whereby said aqueous composition is obtained without precipitation and recovery of a solid polysaccharide and dissolution thereof in an aqueous medium and is suitable for direct use in waterflood oil recovery processes.

Claim 16

Dependent Claim 30 words

The method of claim 13, wherein said composition has a polysaccharide concentration of 0.005 to 1% by weight and a viscosity of 2 to 30 centipoises at the reservoir temperature.

Claim 17

Dependent Claim 29 words

The method of claim 13, wherein the bactericidal agent is sodium azide in an amount of 10 to 2,000 parts per million by weight of the clarified fermentation fluid.

Claim 18

Dependent Claim 18 words

The method of claim 13, wherein the clarification treatment is effected by centrifugation at at least 4,000 g.

Claim 19

Dependent Claim 16 words

The method of claim 13, wherein the polysaccharide-producing microorganism is a microorganism of the Xanthomonas type.

Claim 20

Dependent Claim 32 words

The method of claim 13, wherein the bactericide is a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, wherein said mixture is used in an amount of 10 to 1,000 parts per million by weight.

Claim 21

Dependent Claim 11 words

The method of claim 17, wherein the microorganism is Xanthomonas campestris.

Claim 22

Dependent Claim 35 words

The method of claim 13, wherein the clarification treatment is effected by centrifugation at from 6,000 to 60,000 g, followed by passage through at least one 3μ filter, and thereafter passage through a 0.8μ filter.

Claim 23

Dependent Claim 19 words

The method of claim 13, wherein the clarification treatment is effected by passage through a bed of diatomaceous earth.

Claim 24

Dependent Claim 27 words

The method of claim 13, wherein the clarification treatment is effected by passage through a filter whose pores have an average diameter of at most 3 microns.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-10-31	1987-05-02	1987-11-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-10-31	1991-05-02	1991-11-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-10-31	1995-05-02	1995-11-01	$7700.00	Window Closed / Lapsed

Assisted oil recovery with use of fermentation fluids

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