莺歌海盆地高温超压环境下储层物性影响因素

莺歌海盆地由于独特的沉积地层和温压场特征, 使得盆地内的储层成岩演化也具有了与众不同的过程和特点.通过对莺歌海盆地内有钻井证实的两种超压体系类型(自源型和传导型) 的对比研究, 阐明了其成因差别及其石油地质意义, 并详细论述了高温超压环境下储层物性的影响因素: (1) 储层物性主要受沉积环境和成岩作用控制; (2) 高地温梯度使砂岩的孔隙度衰减较快; (3) 超压保存了一部分原生孔隙, 这是深部储层还具有高孔隙度的最主要原因; (4) 超压通过溶解等成岩作用产生了一些次生孔隙; (5) 流体压裂突破过程中产生了大量的裂缝, 有效地提高了储层渗透性. 

Effects of High Temperature and Overpressure on Reservoir Quality in the Yinggehai Basin, South China Sea

Research into hydrocarbon basins around the world has shown that overpressure is closely connected with hydrocarbon generation and distribution. Because of unique sedimentary sequences and temperature-pressure characteristics, reservoir diagenesis has larruping processes and traits. Through comparing two types of overpressure systems (self-source type and conduction type), confirmed by core and log, this paper illustrates their origin and hydrocarbon value, and sets forth the effects of high temperature and overpressure on reservoir qualities, which include: ① reservoir characteristics are mainly determined by sedimentary environment and diagenesis; ② high geotemperature gradient decreases sandstone porosity; ③ (overpressure) conserves parts of original porosity, which causes high porosity in a deep reservoir; ④ overpressure brings out much of secondary porosity in the processes of diagenesis; ⑤ fluid breakthrough causes cracks, which effectively increase reservoir permeability.