Abstract: A method and a system for oil recovery are provided. An exemplary method includes injecting thickened carbon dioxide (CO2) into the top of a reservoir containing oil. An interface is formed between the thickened CO2 and the oil. The oil is mobilized by the thickened CO2. The mobilized oil is recovered with a recovery well drilled below the reservoir.

Abstract: A method for recovering hydrocarbons from a hydrocarbon bearing formation includes introducing a first solution having a first salt into the hydrocarbon bearing formation. A second solution is also introduced into the hydrocarbon bearing formation, wherein the second solution has a second salt and a foaming agent. The first salt and the second salt produces a nitrogen gas, and the nitrogen gas and the foaming agent produces a foam formed in-situ within the formation. The foam forms a foam barrier, and carbon dioxide is introduced into the formation to form a gas cap, wherein the carbon dioxide gas cap has a gas front that is separated from the hydrocarbons by the foam barrier.

Abstract: A method for enhanced oil recovery from a hydrocarbon bearing subterranean formation includes withdrawing hydrocarbons from a production well extending into the formation, identifying a high permeability streak in the formation, and injecting a dense CO2 composition from an injection well into the high permeability streak. The dense CO2 composition includes dense CO2 and a thickener soluble in the dense CO2. The thickener includes copolymer. The method includes, after injecting the dense carbon dioxide composition into the high permeability streak, injecting an aqueous treatment fluid into the formation.

Abstract: A method and a system for oil recovery are provided. An exemplary method includes injecting thickened carbon dioxide (CO2) into the top of a reservoir containing oil. An interface is formed between the thickened CO2 and the oil. The oil is mobilized by the thickened CO2. The mobilized oil is recovered with a recovery well drilled below the reservoir.

Abstract: A method includes developing a lab-scale representative correlation between wettability index and tracer test return curve data for core samples, obtaining tracer test return curve data for rock at a well of interest, and determining a wettability index of the rock in situ using the representative correlation and the tracer test return curve data for the well. A method includes obtaining core samples of a rock representative of a formation of interest, determining a wettability index of each of the core samples, performing a tracer test on each of the core samples and obtaining tracer return curve data for each of the core samples, building a correlation between the wettability index and the tracer return curve data of the core samples, running a single-well tracer test at a well, obtaining tracer return curve data for the well, and determining a wettability index for the rock of the well.

Abstract: A method includes receiving, by a processing device and from one or more sensors coupled to a water reservoir storing water received from a separator, fluid information. The fluid information includes a water level of the water reservoir. The separator is fluidically coupled to a wellbore string disposed within a wellbore. The method also includes determining, based on the fluid information, operation mode instructions. The method also includes transmitting, to a controller communicatively coupled to at least one flow regulation device fluidically coupled to the wellbore string, the operation mode instructions. The controller controls, based on the instructions, the at least one flow regulation device to regulate, during a production mode of the wellbore string, a flow of production fluid from the wellbore string to the separator or regulating, during a water injection mode of the wellbore string, a flow of water from the water reservoir into the wellbore string.

Abstract: A method for reducing water production from a hydrocarbon bearing subterranean formation includes identifying a high permeability zone in the formation and injecting a dense CO2 composition from a production well into the high permeability zone. The dense CO2 composition includes dense CO2 and a thickener soluble in the dense CO2. The thickener includes a copolymer that is the polymerized reaction product of monomers that include at least one alkenyl ether or dialkenyl ether monomer, at least one acrylate or methacrylate monomer, at least one structural monomer, and at least one allyl ester monomer. After injecting the dense CO2 composition into the high permeability zone, the method includes withdrawing hydrocarbons from the hydrocarbon bearing subterranean formation through the production well. The dense CO2 composition blocks pores in the high permeability zone to reduce or prevent flow of water from the high permeability zone into the production well.

Abstract: A method for recovering hydrocarbons from a hydrocarbon bearing formation includes introducing a first solution having a first salt into the hydrocarbon bearing formation. A second solution is also introduced into the hydrocarbon bearing formation, wherein the second solution has a second salt and a foaming agent. The first salt and the second salt produces a nitrogen gas, and the nitrogen gas and the foaming agent produces a foam formed in-situ within the formation. The foam forms a foam barrier, and carbon dioxide is introduced into the formation to form a gas cap, wherein the carbon dioxide gas cap has a gas front that is separated from the hydrocarbons by the foam barrier.

Abstract: Compositions and methods for treating a subterranean formation. The compositions can include positively and negatively charged divalent ions and a total dissolved solids concentration between 2000 and 3000 ppm. In some implementations, the composition includes calcium and magnesium ions. In some implementations, the composition includes sodium, chloride, and bicarbonate ions. In some implementations, the composition includes iodide, phosphate, or borate ions, or any combination thereof. Methods for treating the subterranean formation can include flowing a first aqueous solution that includes sodium ions into the subterranean formation and flowing a second aqueous solution that has a lower salinity than the first aqueous solution into the subterranean formation, where the second aqueous solution includes positively charged divalent ions, negatively charged divalent ions, and a total dissolved solids concentration between 2000 and 30000 ppm.

Abstract: A method includes receiving, by a processing device and from one or more sensors coupled to a water reservoir storing water received from a separator, fluid information. The fluid information includes a water level of the water reservoir. The separator is fluidically coupled to a wellbore string disposed within a wellbore. The method also includes determining, based on the fluid information, operation mode instructions. The method also includes transmitting, to a controller communicatively coupled to at least one flow regulation device fluidically coupled to the wellbore string, the operation mode instructions. The controller controls, based on the instructions, the at least one flow regulation device to regulate, during a production mode of the wellbore string, a flow of production fluid from the wellbore string to the separator or regulating, during a water injection mode of the wellbore string, a flow of water from the water reservoir into the wellbore string.

Abstract: A method for reducing water production from a hydrocarbon bearing subterranean formation includes identifying a high permeability zone in the formation and injecting a dense CO2 composition from a production well into the high permeability zone. The dense CO2 composition includes dense CO2 and a thickener soluble in the dense CO2. The thickener includes a copolymer that is the polymerized reaction product of monomers that include at least one alkenyl ether or dialkenyl ether monomer, at least one acrylate or methacrylate monomer, at least one structural monomer, and at least one allyl ester monomer. After injecting the dense CO2 composition into the high permeability zone, the method includes withdrawing hydrocarbons from the hydrocarbon bearing subterranean formation through the production well. The dense CO2 composition blocks pores in the high permeability zone to reduce or prevent flow of water from the high permeability zone into the production well.

Abstract: A method for enhanced oil recovery from a hydrocarbon bearing subterranean formation includes withdrawing hydrocarbons from a production well extending into the formation, identifying a high permeability streak in the formation, and injecting a dense CO2 composition from an injection well into the high permeability streak. The dense CO2 composition includes dense CO2 and a thickener soluble in the dense CO2. The thickener includes copolymer. The method includes, after injecting the dense carbon dioxide composition into the high permeability streak, injecting an aqueous treatment fluid into the formation.