Abstract: In general, in one aspect, embodiments relate to a method that includes varying at least a concentration of one or more components of a multi-component sample gas across at least a concentration range while introducing the multi-component sample gas into a gas chromatograph that includes one or more chromatographic columns, measuring concentrations of the one or more components with the gas chromatograph at a first calibration setting, determining one or more non-linearities of the measured concentrations at the first calibration setting, forming a second calibration setting based at least in part on the one or more non-linearities, and measuring concentrations of one or more components of another sample gas with the gas chromatograph at the second calibration setting.

Abstract: A system can displace a headspace associated with a drilling fluid sample with a hydrocarbon blend with a first volume a hydrocarbon gas. The system can also extract the hydrocarbon blend from the head space associated with the drilling fluid sample. The system can further determine a concentration over time of the hydrocarbon gas of the hydrocarbon blend and generating a gas decay curve of the concentration over time of the hydrocarbon gas. Additionally, the system can determine, based on the gas decay curve, a second volume of the at least one hydrocarbon gas. The system may then determine an extraction efficiency correction factor based on a ratio of the first volume to the second volume. The system can correct bias caused by a gas extraction and sampling system during subsequent gas extraction and system operations using the extraction efficiency correction factor.

Abstract: Described herein are systems and techniques for improving operation of equipment that identify compounds included in a slurry that exits a wellbore during a drilling operation. Mass flow rates, volumetric data, wellbore equipment data, and other information may be used to identify a total volumetric density of the slurry. Calculations and/or other evaluations may be performed to identify a volumetric density of materials other than a gas included in the slurry. The volumetric density of the other materials may be subtracted from the total volumetric density to identify a volumetric density of the gas included in the slurry. Estimates of percentages of hydrocarbons and molar mass equations may be used to estimate masses of combined sets of hydrocarbons included in the gas. When a volumetric density of a combined set of hydrocarbons matches the gas volumetric density, the gas may be classified as including the set of hydrocarbons.

Abstract: Described herein are systems and techniques for improving operation of a gas chromatograph or a computer that identifies compounds that correspond to peaks in a graph of gas chromatograph data (chromatogram). Each of the peaks included in the chromatogram may be associated with retention times that are measured amounts of time that correspond to how long it took for respective compounds included in a sample to move through the gas chromatograph. Measured retention times may be compared to standard retention times to identify retention time shifts. These retention times shifts may correspond to a function that may be used to predict retention times of other compounds that could be included in the sample. When a measured retention time that is associated with an unclassified peak in the chromatogram matches a predicted retention time of a specific compound to a threshold level, the unclassified peak may be identified the specific compound.

Abstract: Embodiments of multi-column gas chromatography for analysis of a formation sample are disclosed. In one embodiment, an apparatus comprises a gas chromatography instrument and a controller. The gas chromatography instrument comprises a sample injector; a primary column to separate out a hydrocarbon subset; a secondary column valve coupled to the primary column; a primary detector configured to analyze the hydrocarbons of the subset; a heart cutting unit coupled to the secondary column valve and configured to cut, from the subset, at least one isomer having a weight greater than a threshold; a secondary column coupled to an output of the heart cutting unit configured to separate out the at least one isomer; and a secondary detector configured to analyze the at least one isomer. The controller controls the secondary column valve to output the hydrocarbons to the heart cutting unit in response to at least one trigger event.