中国中西部前陆盆地生储盖组合及成藏基本要素匹配分析

A STUDY ON THE SOURCE-RESERVOIR-SEAL ASSOCIATIONS AND MATCHING OF HYDROCARBON ACCUMULATION FACTORS IN THE FORELAND BASINS IN CENTRAL-WESTERN CHINA

前陆盆地构造特点决定了前陆盆地具有一套特定的成藏地质条件,其构造和沉积控制了生储盖层的发育和储盖组合类型;受多期构造运动的影响和由于多种盆地类型叠加,中国中西部前陆盆地沉积层序多样化,具有多套储盖组合。根据构造和沉积演化特点,在中国中西部前陆盆地划分出了3大套储盖组合,即下部生储盖组合、中部生储盖组合和上部储盖组合,其中下、中部生储盖组合以自生自储组合类型为主,生储盖层相互叠置,具有好的空间配置,但时间匹配较差;上部储盖组合主要为下生上储型,空间的匹配上欠佳,但生烃期、储层成岩阶段和盖层有效封盖等因素在时间匹配上最佳,是时效最佳匹配组合类型,目前发现的油气藏多赋存于该组合。

Structures in foreland basins form a specific geologic condition of hydrocarbon accumulation. The source-reservoir-seal associations are controlled by tectonic and sedimentary evolvement. Sedimentary series and source-reservoir-seal associations in the foreland basins in central-western China are various, affected by several times tectonization and the superposition of several types of original sedimentary basins. According to the sedimentary structure evolvement, three types of source-reservoir-seal associations are divided： Lower source-reservoir-seal associations, Middle source-reservoir-seal associations and Upper reservoir-seal associations. The type of self-generating and self-preserving reservoir is mainly in the Lower and Middle source-reservoir-seal associations, because of the superposed source-reservoir-seal rocks, and the Lower and Middle source-reservoir-seal associations have the best matching of space. The type of lower-generating and upper-reservoiring is mainly in the Upper reservoir- seal associations, as it has the best matching of hydrocarbon generation stage, sandstone diagenesis stage and effective sealing time. The Upper reservoir-seal associations have the best matching of time, where a large number of oil-gas pools have been discovered presently.