Abstract: Methods may include emplacing a wellbore tool in a wellbore, the wellbore tool including a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr, measuring a sample from the wellbore using the wellbore tool, and determining a molecular weight of one or more components of the sample from the measured response of the wellbore tool. Methods may also include establishing a library of one or more chemical components, emplacing a wellbore tool in a wellbore, the wellbore tool including a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr, measuring a sample from the wellbore using the wellbore tool, comparing the measured response from the wellbore tool for the sample with results from the library of one or more chemical components, and determining a molecular weight of one or more components of the sample.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: Methods may include emplacing a wellbore tool in a wellbore, the wellbore tool including a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr, measuring a sample from the wellbore using the wellbore tool, and determining a molecular weight of one or more components of the sample from the measured response of the wellbore tool. Methods may also include establishing a library of one or more chemical components, emplacing a wellbore tool in a wellbore, the wellbore tool including a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr, measuring a sample from the wellbore using the wellbore tool, comparing the measured response from the wellbore tool for the sample with results from the library of one or more chemical components, and determining a molecular weight of one or more components of the sample.

Abstract: Wellbore tools in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr. Systems in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr. Methods in accordance with the present disclosure may include emplacing a wellbore tool in a wellbore, the wellbore tool containing a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr; drawing a sample of a fluid from the wellbore into the wellbore tool; and determining a molecular weight of one or more components of the fluid.

Abstract: Wellbore tools in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr. Systems in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr. Methods in accordance with the present disclosure may include emplacing a wellbore tool in a wellbore, the wellbore tool containing a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10?2 Torr; drawing a sample of a fluid from the wellbore into the wellbore tool; and determining a molecular weight of one or more components of the fluid.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: Methods and devices for determining a plus fraction of a plus fraction of a gas chromatogram are provided. A gas chromatogram may obtained, such as from a downhole gas chromatograph module of a fluid analysis tool. The plus fraction of the gas chromatogram may be determined using one or more of a ratiometric determination, fitting an exponential decay function, and fitting a probability density gamma function.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: Methods and systems are provided for determining a gas/oil ratio using gas chromatography and optical analysis of a fluid sample obtained using a fluid sampling tool. In some embodiments, a gas/oil ratio may be determined from the mass fraction of each light component of the fluid, the mass fraction of each intermediate component of the fluid, a molecular weight of each light component of the fluid, a molecular weight of each intermediate component of the fluid, the density of stock tank oil, the vapor mass fraction of the intermediate components of the fluid, and the mass fraction of the plus fraction of the fluid. In some embodiments, a gas/oil ratio may be determined from the density of stock tank oil, the vapor mole fraction of the intermediate components of the fluid, and the molecular weight of stock tank oil.

Abstract: Methods and devices for determining a plus fraction of a plus fraction of a gas chromatogram are provided. A gas chromatogram may obtained, such as from a downhole gas chromatograph module of a fluid analysis tool. The plus fraction of the gas chromatogram may be determined using one or more of a ratiometric determination, fitting an exponential decay function, and fitting a probability density gamma function.

Abstract: A method for determining a property of a formation is described herein. The method includes positioning a wellbore tool at a location within a wellbore. A formation fluid is withdrawn from the formation using the wellbore tool. The formation fluid is passed through a flow line within the wellbore tool and a formation fluid sample is extracted from the flow line. The method further includes analyzing the formation fluid sample within the wellbore tool to determine a property of the formation fluid sample. The analysis is performed by excluding mud filtrate contamination within the flow line.