V.C. Kelessidis, G. Roberts, J. Williams, ‘New System Provides Continuous Quantitative Analysis of Gas Concentration in the Mud During Drilling’, in 1991 Annual Technical Conference, pp. 219 - 224, doi: http://dx.doi.org/10.2118/19562-PA
Continuous monitoring of hydrocarbon gases in drilling fluids at the surface is essential for identification of prospective reservoir zones as well as for safety. This paper describes a new gas-analysis system that determines the total amount of gas in this mud below the bell nipple. The system is continuous, consistent, and fully quantitative (unlike a gas trap) but not labor-intensive (like a steam still). It also recovers and analyzes gas liberated into the air at the bell nipple, which test results have shown to be almost 50% of the total gas in the mud below the bell nipple.