渤海湾盆地中南部上古生界天然气资源潜力

渤海湾盆地上古生界煤系烃源岩经历了复杂的埋藏史、热史和生烃史，具有多期次的生烃过程，该区上古生界天然气具有晚期成藏特征，古近纪以来所生成的天然气具有较大的资源意义。为此，建立了渤海湾盆地中南部地区上古生界烃源岩的生烃史地质模型，据此对生烃过程进行了数值模拟，通过生成生烃强度随地理坐标和时间变化的三维数据体，实现了对任意平面范围、任意时间段生烃量的定量计算。依据越晚期的生烃量其资源贡献率越高的原理，结合对天然气成藏条件的深入分析，预测了渤海湾盆地中南部地区上古生界天然气资源量的分布规律，进而提出了勘探建议：惠民凹陷的滋镇洼陷、阳信洼陷，东营凹陷南部，东濮凹陷东部次洼、中央隆起带和西部次洼是寻找上古生界天然气的远景区；沾化凹陷孤北地区、东濮凹陷中央隆起带、东营凹陷南坡、惠民凹陷的滋镇洼陷南坡则可作为近期寻找天然气资源的重点区带。

Volume of Natural Gas Resources of the Upper Paleozoic in South-central Bohai Bay Basin

Source rocks in the Upper Paleozoic coal bearing formations in the Bohai Bay basin, which are characterized by complex burial history, thermal history and hydrocarbon generation history, have experienced a multi stage hydrocarbon generation process. The Upper Paleozoic gas pools are characterized by late hydrocarbon accumulation and the volume of gas generated since the Paleogene is relatively large in the study area. A geologic model of hydrocarbon generation history is built for the Upper Paleozoic source rocks in the study area and is used to perform numerical simulation of hydrocarbon generation history. Quantitative calculation of the volume of hydrocarbons generated in any areas and in any time intervals is realized by generating a 3D data set with hydrocarbon generation intensity changing along with geographical coordinates and time. Based on the theory that later hydrocarbon generation contributes more to gas resources and in combination with the analysis of conditions of gas accumulation, this paper predicts the distribution patterns of the Upper Paleozoic gas resources in the study area and presents some proposals for gas exploration. The Zizhen sub sag in Huimin sag, Yangxin sub sag, Southern Dongying sag, and the eastern sub sag, the central uplift zone and the western sub sag in Dongpu sag are recognized as the prospects of the Upper Paleozoic gas pools, while the Gubei area of Zhanhua sag, the central uplift zone of Dongpu sag, the southern slope of Dongying sag and Zizhen sub sag of Huimin sag are identified as the key areas for gas exploration in the near term.