A Study On Hydrocarbon-generating Kinetics Of Source Rocks In Liaodong Bay And Its Application

Through open system and closed system thermal experiments,we studied the oil and gas generation characteristics in different heating rates and types of Paleogene source rocks in Liaodong Bay Area,and solved the kinetic parameters in closed system with parallel first order kinetic and genetic algorithm optimally,and calculated the kinetic parameters in open system with Friedman method.The results show that the oil and gas productive rates of I type organic matters are the best,those of III type organic matters are the lowest;the proportion of gaseous hydrocarbon in total hydrocarbon is related to heating rates,and the proportion of gaseous hydrocarbon in total hydrocarbon under higher heating rates is lower than that under lower heating rates;the activation energy distribution range of I type organic matter is the narrowest,that of III type organic matter is the widest,and that of II₁ and II₂ type are between both;the activation energy peak of gaseous hydrocarbon is usually a little late than that of liquid hydrocarbon;the activation energy has a trend of decreasing with increasing heating rates.Used the easyRo%method to establish geological model,we found that the kinetic parameters under high heating rates of Ro<0.5%and those under low heating rates of Ro>0.5%have better fitting effects.The oil and gas generation patterns in different sub-sags showed that the uplift and erosion in late Dongying group controlled the thermal evolution of organic matter,while the tectonic movement in late Sha-3 has little effect;the oil and gas production rates in Liaozhong Sag are higher than those in Liaoxi Sag,among them,Liaozhongbei sub-sag is the main oil and gas generating area,the oil production rates in Sha-4 and Kongdian group are 100%,the gas production rates are 85%,Liaozhongzhong sub-sag is the second main main oil and gas generating area;there is no oil and gas generated in lower Dong-2 section.The results showed in the above may be caused by the differences of geothermal gradients and buried depth and other factors,the differents of erosion thicknesses have some effects on degrees of hydrocarbon evolution of Liaoxi Sag,but have little effects on those of Liaozhong Sag.