Abstract: A method of improving a field operation that comprises a gas injection may include assessing a plurality of potential injection gases against a plurality of values of a plurality of parameters associated with a plurality of samples, where each of the plurality of potential injection gases comprises an acidic component, and where the plurality of parameters comprises fluid chemistry parameters and rock properties. The method may also include determining a proposed injection gas from among the plurality of potential injection gases for the field operation that comprises the gas injection to be performed using a first wellbore in fluidic communication with a first subterranean formation, a second wellbore in fluidic communication with the first subterranean formation, a third wellbore in fluidic communication with a second subterranean formation, or any combination thereof.

Abstract: An equation state with a mixing rule that captures a multi-component layering within nanopores may be used to model (1) fluid mixture in the nanopores of the reservoir and (2) movement of fluid between the nanopores and large pores of the reservoir. Such modeling of fluid behavior in large pores and nanopores of the reservoir may enable more accurate simulation of the reservoir (e.g., for hydrocarbon recovery).

Abstract: A method for determining the concentration of asphaltenes in a solution is described. A model is first established for estimating the concentration of asphaltenes in a solution based on multiple samples of solutions of asphaltenes in the solvent in which the concentrations are known. The multiple samples have varying concentrations of asphaltenes. The diffusivity and relaxation time are measured for each sample using two-dimensional NMR. The ratio of diffusivity to relaxation time for each sample is then calculated. A linear equation is determined to fit the relationship between the ratio of diffusivity to relaxation time and the asphaltene concentration by weight for the multiple samples, thus creating the model. For a given solution sample for which the concentration of asphaltenes is desired to be determined, diffusivity and relaxation time are determined using two-dimensional NMR, and the ratio of diffusivity to relaxation time is calculated.

Abstract: A storage tank for storing liquids on the seafloor in a subsea environment is disclosed. The storage tank includes a protective enclosure having a removable cover. The storage tank has at least one compartment therein within which is a container including an outer flexible bladder and an inner flexible bladder within the outer flexible bladder. The inner flexible bladder is capable of containing an inner liquid. The space between the inner flexible bladder and the outer flexible bladder is capable of containing an outer liquid. The inner flexible bladder has a liquid inlet capable of connecting to a source of the inner liquid. The inner flexible bladder has a liquid outlet capable of connecting to a line for conveying the inner liquid to a desired location. The storage tank further includes a recirculation loop for circulating the outer liquid in the space between the inner flexible bladder and the outer flexible bladder.

Abstract: A method for determining the concentration of asphaltenes in a solution is described. A model is first established for estimating the concentration of asphaltenes in a solution based on multiple samples of solutions of asphaltenes in the solvent in which the concentrations are known. The multiple samples have varying concentrations of asphaltenes. The diffusivity and relaxation time are measured for each sample using two-dimensional NMR. The ratio of diffusivity to relaxation time for each sample is then calculated. A linear equation is determined to fit the relationship between the ratio of diffusivity to relaxation time and the asphaltene concentration by weight for the multiple samples, thus creating the model. For a given solution sample for which the concentration of asphaltenes is desired to be determined, diffusivity and relaxation time are determined using two-dimensional NMR, and the ratio of diffusivity to relaxation time is calculated.

Abstract: A method for enhancing hydrocarbon recovery in low permeability reservoirs comprises first providing a subterranean reservoir comprising one or more hydrocarbons and water therewithin and a wellbore in fluid communication with the subterranean reservoir. Next, a substantially anhydrous composition is injected into the reservoir through the wellbore. The substantially anhydrous composition comprises carbon dioxide and one or more surfactants. The composition is suitable to form a foam upon contact with the water within the reservoir. The method often results in reduced wellbore corrosion and hydrate formation, reduced reservoir fingering, and enhanced carbon dioxide sweep efficiency over conventional methods.

Abstract: Computer-implemented systems and methods are provided for optimizing hydrocarbon recovery from subsurface formations, including subsurface formations having bottom water or edgewater. A system and method can be configured to receive data indicative of by-pass oil areas in the subsurface formation from reservoir simulation, identify flow barriers in the subsurface formation based on the by-pass oil areas identified by the reservoir simulation, and predict the lateral extension of the identified flow barriers in the subsurface formation. Infill horizontal wells can be placed at areas of the subsurface formation relative to the flow barriers such that production from a horizontal well in the subsurface formation optimizes hydrocarbon recovery.

Abstract: A method for enhancing hydrocarbon recovery in low permeability reservoirs comprises first providing a subterranean reservoir comprising one or more hydrocarbons and water therewithin and a wellbore in fluid communication with the subterranean reservoir. Next, a substantially anhydrous composition is injected into the reservoir through the wellbore. The substantially anhydrous composition comprises carbon dioxide and one or more surfactants. The composition is suitable to form a foam upon contact with the water within the reservoir. The method often results in reduced wellbore corrosion and hydrate formation, reduced reservoir fingering, and enhanced carbon dioxide sweep efficiency over conventional methods.

Abstract: Computer-implemented systems and methods are provided for optimizing hydrocarbon recovery from subsurface formations, including subsurface formations having bottom water or edgewater. A system and method can be configured to receive data indicative of by-pass oil areas in the subsurface formation from reservoir simulation, identify flow barriers in the subsurface formation based on the by-pass oil areas identified by the reservoir simulation, and predict the lateral extension of the identified flow barriers in the subsurface formation. Infill horizontal wells can be placed at areas of the subsurface formation relative to the flow barriers such that production from a horizontal well in the subsurface formation optimizes hydrocarbon recovery.

Abstract: The invention relates to assisting the recovery of petroleum from vertically fractured formations utilizing carbon dioxide gas to lower the interfacial tension between the gas and the petroleum in the vertical fractures and in the formation matrix adjacent the vertical fractures to cause vertical drainage of the petroleum down the fracture system. The invention also includes a method for identifying vertically fractured formations which may be particularly susceptible to such recovery with carbon dioxide gas using the capillary to gravity ratio (1/N.sub.B) to select formations having a value for such ratio of 0.2 or less.