Method of controlling salinity of a low salinity injection water

Patent metadata

Field	Value
Publication number	US-11648511-B2
Application number	US-201816645426-A
Country	US
Kind code	B2
Filing date	Sep 12, 2018
Priority date	Sep 12, 2017
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

A method includes producing a first blended low salinity injection water for injection into at least one injection well that penetrates a first region of an oil-bearing reservoir and producing a second blended low salinity injection water for injection into at least one injection well that penetrates a second region of an oil-bearing reservoir. The reservoir rock of the first and second regions has first and second rock compositions, respectively, that present different risks of formation damage. The first and second blended low salinity injection waters comprise variable amounts of nanofiltration permeate and reverse osmosis permeate. The compositions of the first and second blended low salinity injection waters are maintained within first and second predetermined operating envelopes, respectively, that balance improving enhanced oil recovery from the first and second regions while reducing formation damage upon injecting the first and second blended low salinity injection waters into the oil-bearing reservoir.

First claim

We claim:

1. A method comprising:
producing, with a desalination plant and blending system, a first blended low salinity injection water for injection into at least one injection well penetrating a first region of an oil-bearing reservoir;
producing, with the desalination plant and blending system, a second blended low salinity injection water for injection into at least one injection well penetrating a second region of the oil-bearing reservoir,
wherein the first region and the second region have a first rock composition and a second rock composition, respectively,
wherein the first rock composition and the second rock composition have different risks of formation damage when exposed to a low salinity injection water, and
wherein the first blended low salinity injection water and the second blended low salinity injection water each comprise variable amounts of nanofiltration permeate and reverse osmosis permeate,
injecting the first blended low salinity injection water into the first region while maintaining a composition of the first blended low salinity injection water within a first predetermined operating envelope by adjusting the amounts of the nanofiltration permeate and the reverse osmosis permeate in the first blended low salinity injection water in response to a decrease in injectivity; and
injecting the second blended low salinity injection water into the second region while maintaining a composition of the second blended low salinity injection water within a second predetermined operating envelope by adjusting the amounts of the nanofiltration permeate and the reverse osmosis permeate in the second low salinity injection water in response to a decrease in injectivity,
wherein maintaining the first blended low salinity injection water within the first predetermined operating envelope and maintaining the second blended low salinity injection water within the second predetermined operating envelope comprises controlling an amount of the reverse osmosis permeate and the nanofiltration permeate available for blending in real time by changing an amount of the reverse osmosis permeate discharged from the desalination plant and blending system into a body of water via a reverse osmosis permeate dump line and an amount of nanofiltration permeate discharged from the desalination plant and blending system into the body of water via a nanofiltration permeate dump line, wherein maintaining the first blended low salinity injection water within the first predetermined operating envelope and maintaining the second blended low salinity injection water within the second predetermined operating envelope improves an enhanced oil recovery from the first region and the second region, respectively, and wherein maintaining the first blended low salinity injection water within the first predetermined operating envelope and maintaining the second blended low salinity injection water within the second predetermined operating envelope reduces formation damage upon injection of the first blended low salinity injection water into the first region and injection of the second blended low salinity injection water into the second region, respectively.

2. The method of claim 1 , wherein the first blended low salinity injection water and the second blended low salinity injection water each further comprise variable amounts of seawater.

3. The method of claim 1 , wherein the first blended low salinity injection water and the second blended low salinity injection water each further comprise variable amounts of a fines stabilizing additive.

4. The method of claim 1 , further comprising:
injecting the first blended low salinity injection water into the at least one injection well penetrating the first region of the oil-bearing reservoir;
injecting the second blended low salinity injection water into the at least one injection well penetrating the second region of the oil-bearing reservoir contemporaneously.

5. The method of claim 1 , further comprising:
injecting the first blended low salinity injection water into the at least one injection well penetrating the first region of the oil-bearing reservoir;
injecting the second blended low salinity injection water into the at least one injection well penetrating the second region of the oil-bearing reservoir, wherein the first blended low salinity injection water is injected prior to the injection of the second blended low salinity injection water.

6. The method of claim 1 , wherein the oil-bearing reservoir further comprises a third region of the reservoir, wherein the third region of the oil-bearing reservoir has a different risk of formation damage when exposed to a low salinity injection water than the first region and the second region, wherein the method further comprises:
producing a third blended low salinity injection water for injection into the at least one injection well that penetrates the third region of the oil-bearing reservoir; and
injecting the third blended low salinity injection water into the at least one injection well penetrating the third region of the oil-bearing reservoir,
maintaining a composition of the third blended low salinity injection water within a third predetermined operating envelope,
wherein the third predetermined operating envelope improves an enhanced oil recovery from the third region and reduces formation damage upon injection of the third blended low salinity injection water.

7. The method of claim 6 , wherein the first blended low salinity injection water, the second blended low salinity injection water, and the third low salinity injection water are injected into the at least one injection well simultaneously.

8. The method of claim 6 , wherein the first blended low salinity injection water, the second blended low salinity injection water, and the third low salinity injection water are injected into the at least one injection well sequentially.

9. The method of claim 6 , wherein at least one of the first predetermined operating envelope, the second predetermined operating envelope, or the third predetermined operating envelope defines a sulfate level of less than 100 mg/L.

10. The method of claim 1 , wherein the first predetermined operating envelope and the second predetermined operating envelope comprise one or more boundary values for the composition of the first blended low salinity injection water and the composition of the second blended low salinity injection water, respectively, wherein the one or more boundary values comprise an upper limit and a lower limit for parameters comprising: a total dissolved solids content, a salinity, an ionic strength, a concentration of one or more individual ions, the concentrations of one or more types of individual ions, a ratio of a type of individual ion, and a ratio of an individual ion.

11. A method comprising:
determining an overriding operating envelope for a single blended low salinity injection water, wherein the operating envelope defines boundary values for a region of overlap for a plurality of predetermined operating envelopes for compositions of the blended low salinity injection waters for a first region and a second region of an oil-bearing reservoir, wherein the plurality of predetermined operating envelopes improve enhanced oil recovery from the first region and the second region of the oil-bearing reservoir while reducing formation damage in the first region and the second region,
wherein at least one injection well penetrates the first region, and at least one injection well penetrates the second region,
wherein a reservoir rock of the first region has a first rock composition, wherein a reservoir rock of the second region has a second rock composition, wherein the

Assignees

• Bp Exploration Operating Co Ltd

Inventors

• Collins Ian Ralph
• Couves John William
• Crouch John Henry
• Williams John Dale

Classifications

• B01D61/029 Primary

  Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration · CPC title

• B01D61/08

  Apparatus therefor · CPC title

• B01D2317/04

  Elements in parallel · CPC title

• C02F2209/40

  Liquid flow rate · CPC title

• B01F23/49

  Mixing systems, i.e. flow charts or diagrams · CPC title