车镇凹陷古近系流体异常高压及其对深层碎屑岩储层的影响

Sandstone and conglomerate reservoir affected by fluid abnormal overpressure in deep layer is one of focuses for petroleum exploration and reservoir study. Drilling and oil production test data show that abnormal pressure is exists widely in Shahejie formation of Paleogene, and have closely relationship with oil-bearing and oil productivity. In this study, formation pressure in different formations and in different zones were calculated with equivalent depth method used logging data calibrated by oil production test data. Calculating results show that formation pressure in lower member of No.3 subsection of Shahejie formation (Es3x) is the largest, and its residual formation pressure equals 15~30Mpa. According to the statistics on sandstone and conglomerate's porosity and their residual strata pressure, the porosity increases 2% when strata pressure increased 5MPa. Therefore, the sandstone and conglomerate's porosity in Es3x may be increased by 4-10%. Integration of microcosmic reservoir characteristics and porosity interpretation of logging data, three reasons improving deep sandstone and conglomerate reservoir are listed as follows: (1) fluid abnormal pressure protect original pores and early formed second pores, (2) overpressure environment pressured acidic groundwater into reservoir and form dissolution pores, (3) fluid abnormal overpressure promote the formation of microfractures, and improve the seepage capacity.