THERMAL SIMULATING EXPERIMENT OF SOURCE ROCK AND GASSOURCE CORRELATION IN THE KUQA DEPRESSION OF THE TARIM BASIN

9 samples from the Kuqa Depression of the Tarim Basin were collected and thermal simulated with a step of 40℃ from 260℃ to 540℃.The components and ethane carbon isotopic compositions of gases generated from simulated samples were analyzed.The drying coefficients(C₁/(C₂+C₃)) were figured out.Using drying coefficient of natural gas from Well Ku-1 as parameter for interpolation method,the possible thermal maturities of source rock as well as temperatures are calculated.According to geological background and the possible maturity range,the study showed that only the gas generated at about 420℃ from sample YM-4 of Jurassic coal formation is consistent with Well Ku-1 both in hydrocarbon components and ethane isotopic composition.That means Jurassic coal formation is the main source rock of natural gas from Well Ku-1.Combined with ethane carbon isotope,component and maturity data,the simulating gas drying coefficient can be used in gas-source correlation.The interpolation method overcomes the influence caused by organic thermal maturity and provides a new way for study of oil-gas-source correlation.