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 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: 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: Downhole drilling tools and methods for drilling and detecting carbon dioxide leakage in a subsurface reservoir are disclosed. The tools include a cylindrical body; a sensor module including a plurality of sensors including a first conductive electrode, a second conductive electrode, and a plurality of TiO2 nanotubes, and an electric line located between and connecting the first and the second conductive electrodes; and a communication device communicatively connected to the sensor module; wherein the sensor module and the communication device are attached to an outer surface of the cylindrical body.

Abstract: Certain implementations of the subject matter can be implemented as a method of screening demulsifiers for live crude oil-water emulsions. A live emulsion of a hydrocarbon sample and a water sample is flowed through a capillary viscometer. The live emulsion includes dissolved gases retrieved from a hydrocarbon-carrying reservoir. While flowing the live emulsion through the capillary viscometer, a demulsifier sample is flowed through the capillary viscometer. The demulsifier sample causes breakdown of the live emulsion. Using the capillary viscometer, change in a viscosity of the live emulsion over time resulting from the breakdown of the live emulsion due to the demulsifier sample is measured. Multiple images of the breakdown of the live emulsion over time are captured. A strength of the live emulsion is classified based, in part, on the change in the viscosity of the live emulsion over time and on the plurality of images.

Abstract: Certain implementations of the subject matter can be implemented to screen demulsifiers. A live emulsion of a live hydrocarbon sample and a water sample is flowed through a capillary viscometer. The live hydrocarbon sample includes dissolved gases retrieved from a hydrocarbon-carrying reservoir. While flowing the live emulsion through the capillary viscometer, a demulsifier sample is flowed through the capillary viscometer. The demulsifier sample is capable of causing breakdown of the live emulsion. Using the capillary viscometer, change in a viscosity of the live emulsion over time resulting from the breakdown of the live emulsion due to the demulsifier sample is measured. Multiple images of the breakdown of the live emulsion over time are captured. A strength of the live emulsion is classified based, in part, on the change in the viscosity of the live emulsion over time and on the plurality of images.

Abstract: A method for treating a subterranean formation with a foamed acid system is disclosed. The method includes introducing a treatment fluid into the formation. The treatment fluid includes a first solution and a second solution. The first solution includes an ammonium containing compound and an acid. The second solution includes a nitrite containing compound. One or both of the solutions further include a foaming agent. The solutions are mixed within the formation to generate a nitrogen gas. The method further includes, allowing the compounds to generate nitrogen in the presence of the foaming agent to form a foam and generate the foamed acid system within the formation. The acid present in the foamed acid system reacts with soluble substances in the subterranean formation to increase permeability of the subterranean formation and enable enhanced production of reservoir fluids.

Abstract: A method for treating a subterranean formation with a foamed system is disclosed. The method includes introducing a fracturing fluid into the formation. The fracturing fluid includes a first solution and a second solution. The first solution includes an ammonium containing compound. The second solution includes a nitrite containing compound. One or both of the solutions further include a foaming agent. The solutions are mixed within the formation to generate a nitrogen gas. The method further includes, allowing the compounds to generate nitrogen in the presence of the foaming agent to form a foam and generate the foamed system within the formation. Generation of the foamed system produces sufficient pressure from volumetric expansion to generate fractures in the formation. The fractures are held open with a proppant provided with the fracturing fluid to create a conductive path for production of fluids from the formation to the wellbore.

Abstract: A method for treating a subterranean formation with a foamed acid system is disclosed. The method includes introducing a treatment fluid into the formation. The treatment fluid includes a first solution and a second solution. The first solution includes an ammonium containing compound and an acid. The second solution includes a nitrite containing compound. One or both of the solutions further include a foaming agent. The solutions are mixed within the formation to generate a nitrogen gas. The method further includes, allowing the compounds to generate nitrogen in the presence of the foaming agent to form a foam and generate the foamed acid system within the formation. The acid present in the foamed acid system reacts with soluble substances in the subterranean formation to increase permeability of the subterranean formation and enable enhanced production of reservoir fluids.

Abstract: A method for treating a subterranean formation with a foamed system is disclosed. The method includes introducing a fracturing fluid into the formation. The fracturing fluid includes a first solution and a second solution. The first solution includes an ammonium containing compound. The second solution includes a nitrite containing compound. One or both of the solutions further include a foaming agent. The solutions are mixed within the formation to generate a nitrogen gas. The method further includes, allowing the compounds to generate nitrogen in the presence of the foaming agent to form a foam and generate the foamed system within the formation. Generation of the foamed system produces sufficient pressure from volumetric expansion to generate fractures in the formation. The fractures are held open with a proppant provided with the fracturing fluid to create a conductive path for production of fluids from the formation to the wellbore.

Abstract: Certain implementations of the subject matter can be implemented to screen demulsifiers. A live emulsion of a live hydrocarbon sample and a water sample is flowed through a capillary viscometer. The live hydrocarbon sample includes dissolved gases retrieved from a hydrocarbon-carrying reservoir. While flowing the live emulsion through the capillary viscometer, a demulsifier sample is flowed through the capillary viscometer. The demulsifier sample is capable of causing breakdown of the live emulsion. Using the capillary viscometer, change in a viscosity of the live emulsion over time resulting from the breakdown of the live emulsion due to the demulsifier sample is measured. Multiple images of the breakdown of the live emulsion over time are captured. A strength of the live emulsion is classified based, in part, on the change in the viscosity of the live emulsion over time and on the plurality of images.

Abstract: Certain implementations of the subject matter can be implemented as a method of screening demulsifiers for live crude oil-water emulsions. A live emulsion of a hydrocarbon sample and a water sample is flowed through a capillary viscometer. The live emulsion includes dissolved gases retrieved from a hydrocarbon-carrying reservoir. While flowing the live emulsion through the capillary viscometer, a demulsifier sample is flowed through the capillary viscometer. The demulsifier sample causes breakdown of the live emulsion. Using the capillary viscometer, change in a viscosity of the live emulsion over time resulting from the breakdown of the live emulsion due to the demulsifier sample is measured. Multiple images of the breakdown of the live emulsion over time are captured. A strength of the live emulsion is classified based, in part, on the change in the viscosity of the live emulsion over time and on the plurality of images.