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扶新隆起带南部青山口组普遍发育超压,超压与源下油气成藏关系密切。根据录井、钻测井及室内分析测试等资料,结合沉积埋藏史及生烃史,对该区青山口组超压成因、分布及控制因素进行了研究。结果表明:青山口组超压主要分布在青一段、青二段,“层控”效应明显,超压层测井响应具高声波时差、低密度、低电阻率的特征;下斜坡区超压为欠压实作用与干酪根生烃作用综合作用的结果,属二元成因型超压,而上斜坡区超压则以欠压实作用为主导,属单一成因型超压;单井压力剖面呈钟形,自上而下,压力系数与剩余压力均呈递增性变化;纵向上,青二段压力系数为1.2~1.65,剩余压力为2.5~9MPa,表现为低—中超压,青一段压力系数为1.5~1.85,剩余压力为4.5~11MPa,表现为中—高超压,超压极值分布在青一段;平面上,自长岭凹陷至扶新隆起带方向,随着埋深变浅,超压强度减弱,下斜坡区超压明显高于上斜坡区,剩余压力高值中心主要集中在R48井、R39井及R26-1井等井区;青山口组超压分布呈现较强的非均质性,这种非均质性主要受沉积埋藏速率、暗色泥岩厚度及品质、超压层埋深和断层启闭性等因素控制。超压特征研究可为扶新隆起带南部扶余油层油气成藏认识、盖层封闭性能评价等提供依据。
The Qingshankou Formation in the southern part of the Fuxin uplift zone generally developed overpressure, and the overpressure was closely related to hydrocarbon accumulation under the source. Based on the data of logging, drilling and logging, indoor analysis and testing, combined with the history of sedimentary burial and hydrocarbon generation, the causes of overpressure, distribution and controlling factors of Qingshankou Formation in this area were studied. The results show that the overpressure of the Qingshankou Formation is mainly distributed in the first and the second member of Qingqingshan Formation, and the effect of “stratum control” is obvious. The overpressure logging response is characterized by high acoustic wave time difference, low density and low resistivity. Overpressure is the result of the combined effect of under-compaction and kerogenesis, which is a dual-genotype overpressure. The overpressure in the up-slope region is dominated by under-compaction and belongs to a single genotype overpressure. The pressure profile is bell-shaped, and from top to bottom, the pressure coefficient and residual pressure show an increasing variation. In the longitudinal direction, the pressure coefficient of the second member is 1.2-1.65 and the residual pressure is 2.5-9 MPa, showing low to medium overpressure A pressure coefficient of 1.5 ~ 1.85, the remaining pressure of 4.5 ~ 11MPa, the performance of the medium - high overpressure, extreme pressure distribution in the green section; plane, from the Changling sag to Fuxin uplift zone direction, with the depth of the buried Shallow and overpressure intensity weakened. The overpressure in the lower slope was significantly higher than that in the upper slope. The centers of residual stress were mainly concentrated in well R48, R39 and well R26-1. The overpressure distribution in Qingshankou Formation was stronger Of the heterogeneity, this heterogeneity is mainly affected by sedimentary burial rate, dark mudstone thickness and quality, overburden depth Fault control opening and closing of other factors. The study of overpressure characteristics can provide the basis for the understanding of hydrocarbon accumulation in the Fuyu reservoir in the southern part of Fuxin uplift and the evaluation of seal performance of the cap rock.