Methanol infrared spectral characteristics in offshore gas logging

Methanol infrared spectral characteristics in offshore gas logging. Methanol was found in the logging gases during offshore gas logging by infrared spectra. Logging gas spectra from over 300 offshore wells and 1,000 onshore wells were processed and analyzed, and methanol characteristics were prevalent in the offshore logging gases but not onshore logging gases. The spectra of instruments Alpha111829 and Alpha111834 are studied as examples. The methanol concentrations in some areas exceeded 1 vol%, seriously interfering with the other measurements of alkane gases. Moreover, there are rapid changes in the trends of methanol concentrations. It indicates that methanol does not originate from drilling fluid additives. The results of the correlation analysis show that there are no strong correlations between methanol and the other logging gas component concentrations. Therefore, methanol may be neither a judgmental indicator component gas for natural gas nor oil but a separate energy source. We believe methanol in the offshore logging gases originates from strata. The discovery and analysis of methanol in offshore logging gases are significant in atmospheric and marine environments, oil and gas exploration, geochemistry, and energy.