鄂尔多斯盆地东部上古生界致密岩性气藏成藏模式

Model for tight lithologic gas accumulation in Upper Palaeozoic,east of Ordos Basin

鄂尔多斯盆地东部上古生界气藏为典型的致密砂岩岩性气藏,其特点是气源充足、多层系含气、致密砂岩储集层发育、盖层封闭条件相对较好。根据鄂尔多斯盆地东部气藏形成特征,以成藏期次为主线,以致密岩性圈闭为重点,综合考虑成藏主控因素,分别对早侏罗世末期、晚侏罗世中晚期、早白垩世末期、早白垩世末期至今4个具有代表性的阶段进行了成藏模式分析,认为晚侏罗世中晚期及早白垩世末期是盆地东部天然气成藏的关键时期。受致密岩性圈闭气藏储集层物性差的影响,输导层不同决定了天然气二次运移的方式不同,本溪组、太原组、山西组、下石盒子组形成的天然气气藏在平面上连片性好,而石千峰组及上石盒子组天然气在输导层发育的地方常形成"小而肥"的次生气藏。

The Upper Palaeozoic gas reservoirs in the east of Ordos Basin are typical tight sandstone lithologic reservoirs,which feature abundant gas source,gas contained in multiple series of strata,tight sandstone reservoirs developed and relatively good seal.According to the characteristics of the gas reservoir forming in the east of Ordos Basin,based on the forming periods,focusing on tight lithologic trap,and taking account of key factors for reservoir forming,this paper analyzed the models of gas reservoir-form...