胜利油田石炭-二叠系煤成气生成模式

Generation models of Carboniferous-Permian coal-derived gas in Shengli Oilfield

胜利油田在所属的临清坳陷东部和济阳坳陷发现了石炭-二叠系煤成气,根据该煤系烃源岩的分布与性质、所处构造单元及其演化特征分析,发现隆起、凸起、低凸起、斜坡和洼陷深部等5个构造单元的生烃史存在明显差别。将煤岩一次和二次生烃模拟实验得到的活化能等动力学参数与不同构造单元的埋藏史相结合,建立了不同构造单元煤成气生成量与地质年代的数量关系,得到了5种煤成气生成模式:隆起区中晚期不生烃模式;凸起区晚期不生烃模式;低凸起晚期成熟—高熟生烃模式;斜坡带晚期成熟—高熟生烃模式;深洼带晚期过熟生烃模式。研究表明:临清坳陷东部洼陷带、惠民凹陷南坡、沾化凹陷罗家斜坡带、车镇凹陷东部斜坡带、埕东凸起北部斜坡带等发育高成熟气源灶,斜坡带及周边地区是最为有利的煤成气勘探区。

Coal-derived gas from the Carboniferous Permian coal-measures is discovered in east Linqing Depression and Jiyang Depression in the Shengli Oilfield. Investigation on the distribution, characteristics, structure and thermal evolution of the coal- measure source rock reveals that there are obvious differences in hydrocarbon generation histories in five structural units including high, uplift, lower uplift, slope and deep sag. The active energy of primary and secondary generations and other parameters from the thermal simulations of coal samples were calculated and associated with the burial histories of the five structural units, establishing the quantitative relations of coal-derived gas generation and geological times. There are 5 coal-derived gas generation models： no generation in the high area at middle-late stage; no generation in the uplift area at late stage; mature to highly mature generation in the lower uplift at late stage; mature to highly mature generation in the slope at late stage; over-mature generation in the deep sag at late stage. Highly mature gas source kitchens are developed in eastern sag of Linqing Depression, southern slope of Huimin Sag, Luojia slope of Zhanhua Sag, eastern slope of Chezhen Sag, and northern slope of Chengdong Uplift; the slopes and their surrounding areas are the most favorable areas for coal-derived gas.