Enhanced surfactant polymer flooding processes for oil recovery in carbonate reservoirs
AssigneeSaudi Arabian Oil Company
InventorsSubhash AYIRALA, Abdulkareem M. AL-SOFI, Jinxun WANG, Ali Abdallah AL-YOUSEF
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Abstract
A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising a surfactant, the surfactant operable to reduce interfacial tension, a polymer, the polymer operable to increase the viscosity of the composition, and a tailored water, the tailored water operable to alter a wettability of the in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm, where the total dissolved solids comprises a salt, where the composition has a viscosity between 3 cP and 100 cP.
Claims20
A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising:
- a surfactant, the surfactant operable to reduce interfacial tension;
- a polymer, the polymer operable to increase a viscosity of the composition;
- and
- a tailored water, the tailored water operable to alter a wettability of in-situ rock in the carbonate reservoir,
- where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm,
- where the total dissolved solids comprises a salt,
- where the composition has a viscosity between 3 cP and 100 cP.
A method of recovering oil from in-situ rock in a carbonate reservoir, the method comprising the steps of:
- injecting a first injection into an injection well, where the first injection comprises a slug of a tailored water with a polymer, where the first injection has a viscosity between 3 cP and 100 cP;
- injecting a second injection into the injection well, where the second injection comprises a slug of a tailored water formulation, where the tailored water formulation has a viscosity between 3 cP and 100 cP;
- injecting a third injection into the injection well, where the third injection comprises a slug of the tailored water with the polymer, where the first injection has a viscosity between 3 cP and 100 cP;
- injecting a fourth injection into the injection well, where the fourth injection comprises a slug of the tailored water;
- and
- allowing the slugs to interact with the in-situ rock to produce mobilized oil, where the interaction between the slugs and the in-situ rock is operable to free oil from pores of the in-situ rock, where the mobilized oil comprises the freed oil.
The method of 10, where a total volume of the slug of the tailored water with polymer in the first injection is between 0.01 pore volumes (PV) and 0.1 PV.
The method of 10, where a total volume of the slug of the tailored water formulation in the second injection is between 0.1 PV and 0.5 PV.
The method of 10, where a total volume of the slug of the tailored water with polymer in the third injection is between 0.3 PV and 1.0 PV.
The method of 10, where a total volume of the slug of the tailored water in the fourth injection is between 1.0 PV and 2.0 PV.
A method of making a tailored water formulation, the method comprising the steps of:
- treating a seawater with a water chemistry alteration technology to produce a tailored water, where the tailored water is operable to alter a wettability of in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm;
- adding a polymer to the tailored water;
- adding a surfactant to the tailored water to form the tailored water formulation;
- and
- mixing the tailored water formulation, where the tailored water formulation has a viscosity between 3 cP and 100 cP.
Dependencies are inferred from the claim text.