油气成藏过程中的地质门限及其控制油气作用

GEOLOGIC THRESHOLDS IN THE PROCESS OF FORMING OIL AND GAS RESERVOIR AND THEIR FUNCTIONS OF CONTROLING PETROLEUM

油气在生排运聚成藏过程中须经历生烃、排烃、运烃、聚烃和资源等 5个门限。某一确定的油气运聚成藏系统进入任一个门限都将损耗一部分烃量。在实际地质条件下 ,源岩生成的烃量只有超过进入各个门限时损耗烃量之和才能大规模聚集成藏 ,并构成油气勘探的远景区。根据物质平衡原理研究油气生成量和损耗量之间的平衡关系 ,建立了相应的地质模型。在此基础上 ,提出了门限控烃作用及其计算模型。文中阐明了各门限的地质含义、判别标准及其控油气作用机理 。

A series of thresholds, such as hydrocarbon generation threshold, hydrocarbon expulsion threshold, hydrocarbon migration threshold, hydrocarbon accumulation threshold, resource threshold, may be experienced in the process of forming reservoir. A certain forming reservoir system of petroleum would consume a part of hydrocarbon and then reach a threshold. The generated hydrocarbon from source rock could be accumulated in large scale so as to form a promising exploration area only when it exceeds the amount of consumed hydrocarbon in the process of crossing every threshold in practical geologic conditions. Geologic meaning, judge standard and mechanism of controlling petroleum of every threshold are clarified and some application cases are listed. The functions of five geological thresholds for controlling oil and gas are described. Some calculation formulas are presented.