The Evaluation Of Deep Source Rocks In Changling Fault Depression Of Songliao Southern Basin

People found that hydrocarbon gas distribution and the distribution of source rocks are closely related during the natural gas exploration in the south of the SongLiao Basin.. People have clearly recognized that the shallow southern basin is rich in oil and gas resources ,compared to which ,the understanding of the oil and gas potential in the deep is still relatively vague. This has become the region's problems in the deep gas exploration which remains to be solved.To solve this problem,this paper starts qualitative and quantitative evaluation of deep source rocks of Changling depression in the south of the SongLiao Basin deep source rocks qualitative and quantitative evaluation,which will provide the basis for the further work of deep gas exploration.This paper estimate the abundance, type and maturity of the source rock with the measured geochemical data combined with logging geochemical methods.The results show that Shahezi of the abundance of organic matter in Changling fault is better than Yingcheng.In which the Shahezi is slightly better than the Yingcheng in Qianbei depression ,and other depressions are mainly to Shahezi.The types of organic matter in Yingcheng of Haerjin ,fulongquan and Hashituo and Shahezi of Fulongquan are mainlyⅡ1 ~Ⅱ2 type,and others are mainly typeⅡ2 ~Ⅲ.The maturity is primarily high mature to overripe.First,quantitative evaluation of hydrocarbon source rocks is to restore the earth history and thermal history,which provide temperature for hydrocarbon generation,and then establish the hydrocarbon profile of the study area according to the results of thermal simulation experiments,on the basis of which to recover the original organic carbon and hydrocarbon potential.This paper calculates the probability distribution of the geochemical parameter using Monte Carlo method and last calculate the amount of hydrocarbon generation and expulsion in different periods in conjunction with chemical dynamic method. Through quantitative calculation,the amount of gas generated of Shahezi is higher than Yingcheng in Changling depression,so we determine Shahezi as the main source rock.This paper analyse the causes of natural gas using natural gas components, carbon isotope , noble gas isotopic composition and light hydrocarbons as well as other indicators.This shows that there are oil-faulted gas, coal gas, inorganic gas, as well as one of the two mixed gas in Changling depression. The gas source comparison using the maturity of natural gas and light hydrocarbon fingerprint shows that the hydrocarbon gas is primarily from Shahezi in Changling rift.