渤海湾盆地北部深层碎屑岩储层孔隙度影响因素探讨

A discussion on factors to control porosity of deep-buried clastic reservoirs in the northern Bohai Bay basin

讨论了影响渤海湾盆地北部深层(埋深>3500m)碎屑岩储层孔隙度的地质因素,认为沉积相带控制着深层储层的物性,河流和三角洲砂体储层的孔隙度经后期改造后仍相对较高;生烃潜力大的坳陷,其烃源岩有机酸排放量大,储层次生孔隙相对发育;高加热速率有利于油气的早生、早排和早期充注,从而抑制胶结作用,有利于储层孔隙的保护,孔隙度相对较高;超压可以增加化学反应的活化能,延迟烃源岩有机酸的生成和储层的溶蚀作用,减小机械压实作用对储层孔隙的影响,可起到保护储层孔隙的作用。

The factors to control porosity of deepburied （〉3 500 m） clastic reservoirs are discussed in the northern Bohai Bay basin, resulting in several conclusions. These deep-buried reservoirs petrophysical property is still controlled by their sedimentary facies, and the sandbodies of fluvial and delta facies are still higher in porosity after their later modification. In depressions with high potential of hydrocarbon generation, secondary porosity is relatively developed in reservoirs because large amounts of organic acids are expelled from source rocks. The high rate of heating iS favorable to early generation, expulsion and charge of hydrocarbon, which may inhibit cementation and maintain porosity in reservoirs. Overpressures may play a role in protection of reservoir porosity because they can increase active energy of chemical reactions, retard generation and expulsion of organic acids from source rocks and solution of reservoirs, and decrease effects of mechanical compaction on reservotr porosity.