LOGGING TECHNIQUES FOR GAS DRILLING IN SICHUAN BASIN

New gas drilling techniques have significant influences on the outlet engineering parameters of traditional logging, conventional geologic logging and mud logging. In particular, they weaken useful information and complicate cutting discrimination, making it more difficult to determine lithology, to divide layers, to make geologic engineering prediction, and to recognize oil/gas shows. This paper studies the typical characteristics of engineering logging, determination of lag time of conventional geologic logging, methods of cutting sampling and discrimination, common cutting features and fluorologging techniques for gas drilling, as well as gas sampling and analysis and monitoring of oil, gas and water during mud logging. It presents a set of logging techniques that are adapted to gas drilling. Their application to over 20 gas wells in Sichuan Basin shows that the logging data are complete and accurate. It also presents proposals for improving current acquisition methods of logging information and developing logging while drilling techniques.