The present disclosure provides compositions, methods, and systems for identifying marked hydrocarbon fluids. These compositions, methods, and systems utilize a gas chromatography marker including a pyrrolidinone. The methods and systems can identify the presence or absence of the gas chromatography marker and/or the pyrrolidinone. The compositions, methods, and systems can optionally utilize a spectroscopic marker.

A reversible enrichment material, its preparation and application thereof are provided. The reversible enrichment material includes an inorganic carrier; and an active metal salt, a first metal salt promoter and a second metal salt promoter supported on the inorganic carrier. The active metal salt is a soluble silver salt, a soluble copper salt, or a combination thereof. The first metal salt promoter is one or more selected from the group consisting of soluble salts of Group IA, Group IIA and Group IIIA metals, and the second metal salt promoter is one or more selected from the group consisting of soluble salts of transition metals other than Group IB metals. The reversible enrichment material can realize effective separation of saturated hydrocarbon from unsaturated hydrocarbon and has good reversibility.

A method to simulate distillation of a petroleum stream by gas chromatography can include separating the petroleum stream with a gas chromatograph as a function of boiling point; passing the separated petroleum stream through a vacuum ultraviolet detector to yield data comprising a vacuum ultraviolet signal as a function of boiling point; integrating the vacuum ultraviolet signal as a function of boiling point over two or more wavelength ranges to derive relative concentrations of two or more components of the separated petroleum stream that correspond to the two or more wavelength ranges.

A system includes a phase behavior analysis unit having a housing, a heating system connected to the housing and arranged to heat an interior of the housing, a pressure cell positioned in the interior of the housing, and a three-way valve with one inlet fluidly connected to a chamber in the pressure cell and two outlets. The system also includes a gas chromatograph that is fluidly coupled to the chamber in the pressure cell via the three-way valve.

A method for determining corrosion inhibitor residual concentration of a hydrocarbon sample is described. The hydrocarbon sample is mixed with a standard solution to form a first mixture. The standard solution includes a corrosion inhibitor in a known concentration. The first mixture is mixed with an aqueous saline solution to form a second mixture. The aqueous saline solution includes about 1% salt concentration or greater. The second mixture is agitated for about 1 hour or longer and at a temperature of about 50 degrees Celsius (° C.) or greater. After agitation, a hydrocarbon phase and an aqueous phase of the second mixture are allowed to separate. A portion of the aqueous phase is obtained. The portion of the aqueous phase is analyzed to determine a corrosion inhibitor residual concentration of the hydrocarbon sample.

Methods and a system for determining a composition of a fluid from a reservoir are provided. An exemplary method includes depressurizing a single-phase fluid to atmospheric pressure to separate a gas phase from a liquid phase, recording the volume of the gas phase, determining the weight of the liquid phase, and determining an atmospheric gas-oil ratio (GOR) from the volume of the gas phase and the weight of the liquid phase. The method also includes determining the composition of the gas phase to C9+, measuring the density of the liquid phase, determining the molecular weight of the liquid phase, and determining the composition of the liquid phase to C45+. The total hydrocarbon composition of the fluid is calculated from the amount of the gas phase, the amount of the liquid phase, the composition of gas phase, the composition liquid phase, and the atmospheric GOR.

One or more embodiments of the present disclosure include a gas-analysis system. The gas-analysis system may include a first valve, a gas-measurement device, and a second valve. The first valve may be between a sample-gas line and a sample-gas outlet. The first valve may be configured to either allow or prevent gas movement between the sample-gas line and the sample-gas outlet. The gas-measurement device operatively coupled to a testing-gas line. The second valve may be between the sample-gas line, a flushing-gas inlet, and the testing-gas line. The second valve may be configured to allow gas movement from one of the sample-gas line or the flushing-gas inlet to the testing-gas line.

Method for adapting the concentration of a sample gas in a gas mixture to be analysed by a gas chromatograph assembly, the assembly comprising a sample gas inlet, a secondary gas inlet, a gas chromatograph sensor, a gas chromatograph column, and a gas chromatograph bypass parallel to the column, characterized by a) introducing sample gas through the sample gas inlet, b) introducing secondary gas through the secondary gas inlet, c) mixing the sample gas and the secondary gas to a gas mixture and conducting the mixture via the bypass, d) circulating the mixture in a gas conducting loop comprising the bypass and the sensor, e) repeating steps b), c) and d) without step a) to gradually reduce the concentration of sample gas within the mixture until the concentration reaches a desired predetermined level, f) analysing the mixture by means of gas chromatography employing the column and the sensor.

A method for evaluating a degree of transformation ratio of kerogen to oil and/or gas and/or gas to oil generation index using a pyrolysis gas chromatography is disclosed. The method comprises providing a rock sample in powdered form; determining, by a source rock analysis instrument, total organic carbon in said rock sample, remaining hydrocarbon generation potential in rock sample, and a maturity of rock sample; feeding said sample in a pyrolyzer if said sample satisfies a pre-defined condition; analyzing, said sample in said pyrolyzer, by heating said sample at a pre-specified pyrolysis temperature in pre-specified pyrolysis steps and for pre-specified pyrolysis time; determining, by a gas chromatograph, a peak area of hydrocarbons present in said sample analyzed; evaluating, in a said degree of transformation ratio of said sample to oil and/or gas and/or said gas to oil generation index.

The present invention relates to systems and methods for finding and sampling hydrocarbons from seeps in water or from artificial sources of water. The present invention related to systems and methods for in situ analyzing fluid samples in a body of water. The systems and methods can be used to find hydrocarbons and associated non-hydrocarbons from seeps in water. Such seeps may come from natural sources in deep water, possibly as deep as 3000 m or even more.