松辽盆地嫩江组高有机质丰度页岩生烃特征及原位转化数值模拟OA

The shale of the Nenjiang Formation in the Songliao Basin generally exhibits a high total organic carbon content(TOC),locally exceeding 10%.However,the shale is mainly at low-to-medium maturity stage,making it a potential target stratum for in-situ conversion development.Although it is generally believed that higher TOC indicates greater hydrocarbon generation potential,there is still a lack of sufficient understanding regarding whether the in-situ conversion characteristics of different intervals depend solely on their TOC.Optimizing the most economical development intervals under a high TOC background requires additional selection criteria.In this study,two typical Nenjiang Formation shale samples with different organic abundance(with TOC of 9.63%and 5.08%respectively)are selected.Hydrocarbon generation kinetic parameters are obtained through thermal simulation experiments.By coupling the temperature field,an electric-heating in-situ conversion model is established to evaluate the in-situ development potential of the two typical Nenjiang Formation shales with varying abundances.The results indicate that both shale samples from the Nenjiang Formation predominantly generate oil.The high organic abundance shale yields more oil,whereas the low organic abundance shale has a slightly higher gas-oil ratio(GOR).With increasing heating time,the equivalent vitrinite reflectance(Easy Ro%)gradually increases from the heating well center to the periphery.By the third year,the Easy Ro%in the area within a 13 m radius from the heating well had exceeded 1.2%,indicating that the thermal maturation of organic matter in the main hydrocarbon generation zone is essentially completed.Under in-situ conversion conditions,both shales begin to generate significant amounts of oil after approximately two years of heating,reaching over 80%of their peak oil production rates in the third year.Furthermore,the cumulative oil production of the high organic abundance shale is about twice that of the low organic abundance shale.Given its higher cumulative oil production,the high organic abundance shale demonstrates superior in-situ development potential.These findings provide important theoretical support and exploration directions for the in-situ development of low-to-medium maturity shales of the Nenjiang Formation in the Songliao Basin.