Considering the action mechanisms of overpressure on physical changes in skeletal grains of deep reservoir rocks and the differences in physical changes of skeletal grains under overpressure and hydrostatic pressure, the sandstone of the Jurassic Toutunhe Formation in the southern margin of Junggar Basin was taken as an example for physical modeling experiment to analyze the action mechanisms of overpressure on the physical properties of deep reservoirs. (1) In the simulated ultra-deep layer with a burial depth of 6000–8000 m, the mechanical compaction under overpressure reduces the remaining primary pores by about a half that under hydrostatic pressure. Overpressure can effectively suppress the mechanical compaction to allow the preservation of intergranular primary pores. (2) The linear contact length ratio under overpressure is always smaller than the linear contact length ratio under hydrostatic pressure at the same depth. In deep reservoirs, the difference between the mechanical compaction degree under overpressure and hydrostatic pressure shows a decreasing trend, the effect of abnormally high pressure to resist the increase of effective stress is weakened, and the degree of mechanical compaction is gradually close to that under hydrostatic pressure. (3) The microfractures in skeletal grains of deep reservoirs under overpressure are thin and long, while the microfractures in skeletal grains of deep reservoirs under hydrostatic pressure are short and wide. This difference is attributed to the probable presence of tension fractures in the rocks containing abnormally high pressure fluid. (4) The microfractures in skeletal grains under overpressure were mainly formed later than that under hydrostatic pressure, and the development degree and length of microfractures both extend deeper. (5) The development stages of microfractures under overpressure are mainly controlled by the development stages of abnormally high pressure and the magnitude of effective stress acting on the skeletal grains. Moreover, the development stages of microfractures in skeletal grains are more than those under hydrostatic pressure in deep reservoir. The multi-stage abnormally high pressure plays an important role in improving the physical properties of deep reservoirs.

考虑超压对深层储集岩骨架颗粒物理变化的作用机制以及超压与静水压力下骨架颗粒物理变化的差异，以准噶尔盆地南缘侏罗系头屯河组砂岩为例进行物理模拟实验，分析超压对深层储层物性的作用机制。 (1) 在模拟埋深6 000~8 000 m的超深层中，超压下的机械压实作用使剩余原生孔隙减少了约静水压力下的一半。超压可有效抑制机械压实作用，使粒间原生孔隙得以保存。 (2) 在相同深度，超压下的线接触长度比总是小于静水压力下的线接触长度比。深层油藏超压下机械压实程度与静水压力下机械压实程度差异呈现减小趋势，异常高压抵抗有效应力增加的作用减弱，机械压实程度逐渐接近静水压力下机械压实程度压力。 (3)超压作用下深层储层骨架颗粒微裂缝细而长,而静水压力作用下深层储层骨架颗粒微裂缝短而宽。这种差异归因于含有异常高压流体的岩石中可能存在拉伸裂缝。 (4)超压下骨骼晶粒的微裂缝形成时间主要晚于静水压下的微裂缝发育程度和长度。 (5)超压微裂缝发育阶段主要受异常高压发育阶段和作用在骨架颗粒上的有效应力大小的控制。而且深层储层中骨骼颗粒微裂缝的发育阶段比静水压力下的微裂缝发育阶段要多。多期异常高压对改善深层储层物性具有重要作用。