Oil recovery processes at high salinity carbonate reservoirs

Patent metadata

Field	Value
Publication number	US-2016289539-A1
Application number	US-201514673604-A
Country	US
Kind code	A1
Filing date	Mar 30, 2015
Priority date	Mar 30, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A process for recovering oil from a carbonate reservoir of high salinity, wherein supercritical CO 2 floodings are combined with a fluorosurfactant in the tertiary recovery. Embodiments include alternating injection and co-injection schemes of the supercritical CO 2 and the fluorosurfactant. A stable fluorosurfactant-CO 2 foam that is not susceptible to the harsh conditions of the reservoir (temperature, pressure and salinity) can be successfully generated, leading to a reduction in the mobility of CO 2 , an increase in the mobility of the reservoir oil, higher contact between the injected fluid with the oil and a better sweep efficiency of the oil.

First claim

1 : A process for recovering hydrocarbon from a carbonate reservoir, comprising:
injecting the carbonate reservoir with a first solution to recover a first amount of hydrocarbon; injecting the carbonate reservoir with a second solution and a third solution to recover a second amount of hydrocarbon, the second solution comprising a fluorosurfactant and the third solution comprising supercritical CO 2 ; wherein the injecting with the second solution and the third solution displaces the second amount of hydrocarbon from the carbonate reservoir by pushing the second amount of hydrocarbon and reducing the viscosity of the second amount of hydrocarbon.

2 : The process of claim 1 , wherein the first solution is an aqueous solution having a salinity of 20,000 ppm to 200,000 ppm.

3 : The process of claim 1 , wherein the first solution is natural sea water having a salinity of from 55,000 to 60,000 ppm.

4 : The process of claim 1 , wherein the second solution is an aqueous solution having a fluorosurfactant concentration of 0.05-0.3 vol. % and a salinity of 20,000 ppm to 200,000 ppm.

5 : The process of claim 1 , wherein the second solution is an aqueous solution having a fluorosurfactant concentration of 0.1 to 0.2 vol. % and a salinity of 55,000 to 60,000 ppm.

6 : The process of claim 1 , wherein the fluorosurfactant is amphoteric and comprises a hydrophobic chain having no more than 12 carbon atoms.

7 : The process of claim 1 , wherein the second solution is substantially free of a non-fluorinated cosurfactant compound.

8 : The process of claim 1 , wherein the third solution has a supercritical CO 2 of at least 70 vol. % and a salinity of no higher than 1000 ppm.

9 : The process of claim 1 , wherein the second solution and the third solution are injected alternately in a plurality of cycles, each cycle comprising one discontinuous fluorosurfactant slug and one discontinuous supercritical CO 2 slug, each discontinuous slug comprising 0.1 to 2.5 pore volumes of the second solution or the third solution.

10 : The process of claim 1 , wherein the second solution and the third solution are injected simultaneously in one continuous fluorosurfactant slug and one continuous supercritical CO 2 slug, each continuous slug comprising 1.5 to 5.0 pore volumes of the second solution or the third solution.

11 : The process of claim 9 , wherein the discontinuous surfactant slug is injected before the discontinuous supercritical CO 2 slug in each of the plurality of cycles at a volume ratio of x:y, where x and y are independently an integer of 1 to 9.

12 : The process of claim 9 , wherein the discontinuous surfactant slug is injected before the discontinuous supercritical CO 2 slug in each of the plurality of cycles at a volume ratio of 1:3.

13 : The process of claim 1 , wherein the viscosity of the oil is reduced by 65-80%.

14 : The process of claim 1 , recovering at least 50% of the original oil in place in the carbonate reservoir.

15 : The process of claim 1 , wherein the injecting with the second saline solution and the third solution recovers at least 30% of the oil left in the carbonate reservoir after the injecting with the first saline solution.

16 : The process of claim 1 , wherein the injecting with the second saline solution and the third solution provides at least 15% incremental oil recovery after the injecting with the first saline solution.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Jangda Zaid Zaffar
• Sultan Abdullah S

Classifications

• E21B43/24

  using heat, e.g. steam injection · CPC title

• Y02P90/70

  Combining sequestration of CO2 and exploitation of hydrocarbons by injecting CO2 or carbonated water in oil wells · CPC title

• C09K8/584 Primary

  characterised by the use of specific surfactants · CPC title

• E21B43/20

  Displacing by water · CPC title

• C09K8/594

  Compositions used in combination with injected gas {, e.g. CO2 orcarbonated gas}(C09K8/592 takes precedence) · CPC title