Application of Gas Logging Hydrocarbon Index in Xihu Sag

Traditional oil and gas discrimination methods by gas survey logging, such as P1XLER and hydrocarbon triangular plot, has great limitations, and can not be directly used to evaluate hydrocarbon characteristics in Xihu Sag. By collecting lots of hydro-carbon component data of test formation in study area, we figure out the hydrocarbon humidity index and hydrocarbon density index and finally establish the hydrocarbon gas index plot for Xihu Sag. 9 test layers of 8 wells are used to test the validity and the number is 77.8%, indicating that the index illustration method is effective and can be a good guide for field assessment of oil and gas layers.