Characteristics Of Carboniferous-Permian Hydrocarbon Source Rocks In The Bohai Bay Basin And Their Evaluation

In recent years, with deep-going research and ongoing exploration, China's various petroleum companies have successively completed a number of special research projects such as integrated assessments of deep-seated petroleum geological conditions, early evaluation of Paleozoic blocks and deep-seated natural gas and coal gas in major petroleum-bearing areas of eastern China, and major advances have been made in the evaluation of the hydrocarbon-generating conditions of deep-seated hydrocarbon sources rocks. This study was conducted to meet the requirements of the research on hydrocarbon generation in Upper Paleozoic coal measures in relation to the Sinopec-Chinese Academy of Geological Sciences cooperative project "Constraints of the Tanlu fault zone on petroleum-bearing basins on its two sides and petroleum prospects". On the basis of previous research and according to an analysis of main core samples from the Upper Paleozoic in the Bohai Bay basin, combined with a wealth of data, the author has performed an integrated analysis of the types and content of maceral, abundance, types and maturity of organic matter and sediment organic phase in hydrocarbon source rocks of Carboniferous-Permian coal measures in the study region, revealed the spatial distribution of effective hydrocarbon source rocks of Carboniferous-Permian coal measures in the Bohai Bay basin and delineated favorable hydrocarbon-generating blocks.According to the evaluation conditions for favorable hydrocarbon-generating blocks, an integrated evaluation of favorable petroleum-generating areas in the Bohai Bay basin has been made from the distribution of hydrocarbon source rocks, abundance, types and maturity of organic matter and sediment organic phase. In the Jiyang block depression, the hydrocarbon source rocks are thinner than those in central Hebei and the Huanghua area, the organic matter abundance is low and the organic matter is of III type; so the area has poor hydrocarbon-generating potential. Generally the Huanghua block depression is a rather favorable area, and the most favorable hydrocarbon-generating blocks are the Kongxi buried hill and Xuhei buried hill, followed by the Qikou subbasin and Nanpi subbasin. The Suqiao-Wen'an area in the Wen'an block depression, where various conditions are suitable for petroleum formation, is a good area for the formation of oil/gas accumulations. The Linqing block depression, where the maturity is moderate and the organic matter abundance is high, is also a favorable area for oil and gas generated from coal.