摘要
油溶释放气是济阳坳陷中浅层天然气的重要来源。文中应用盆地模拟技术 ,确定了济阳坳陷烃源岩大约在 390 0m进入大量生气窗。该坳陷烃源岩埋深较浅 ,以生油为主 ,仅在洼陷的中心进入大量生气窗 ,在此基础上阐明了油溶释放气是济阳坳陷中浅层天然气的重要来源。并从油溶解气的模型出发 ,结合油气藏实测数据 ,确定了油溶解气起始脱气点的计算方法 ,建立了典型的脱气模式。认为济阳坳陷油溶解气的起始脱气深度大约在 170 0～ 2 0 0 0m之间 ,埋深小于起始脱气深度 ,可形成气层气、气顶气和夹层气等天然气藏 ;埋深在起始脱气深度至 390 0m之间 ,气藏在油中处于欠饱和状态 ,以溶解气赋存形式为主 ;深度大于 390 0m ,烃源岩才开始进入大量游离气生成阶段 。
Gas released from dissolved gas in oil is an important source of natural gas in shallow reservoirs in Jiyang depression. Basin simulation shows that source rock in Jiyang depression is determined to reach threshold of generating a large amount of gas at the depth of about 3900m. Source rock is buried shallower and generation of oil was dominating in the basin,and only in the center of sag it reaches threshold of generating a large amount of gas. Therefore, gas released from dissolved gas in oil is an important source of natural gas in shallow reservoir in Jiyang depression. From dissolved gas model, combined with measured data of reserviors, method for calculation of the beginning degasification of dissolved gas in oil is derived and typical degasification model is constructed. It is suggested that the depth at which the dissolved gas in oil begin to degas in Jiyang depression ranges from about 1700m to 2000m, and the depth to the source rock is less than the depth at which degasification begins, and natural gas reservoir such as gas reservoir in gas cap and intercalated reservoir and so on, then can be formed; that at a depth between the depth of beginning degasification and 3900m, gas reservoir is unsaturated and accumulated as dissolved gas; that at a depth greater than 3900m, source rock begins to go into the phase of generating a large amount of free gas, and then the deep primary gas pool can be formed.
出处
《地学前缘》
EI
CAS
CSCD
2000年第4期555-560,共6页
Earth Science Frontiers
关键词
油溶解气
脱气作用
脱气模式
运移
成藏机理
dissolved gas in oil
outgassing
Jiyang depression
degasification model
