松辽盆地徐家围子断陷深层区域成岩规律和成岩作用对致密储层含气性的控制

Regional Diagenetic Law and Control of Diagenesis over Gas-Bearing Capacity of Tight Reservoirs in Deep Xujiaweizi Fault Depression, Songliao Baion

为了研究松辽盆地徐家围子断陷深层的区域成岩规律及其影响因素和成岩作用对致密储层含气性的控制,本文进一步细分了成岩阶段,并分别研究了各构造单元的成岩特征,应用流体包裹体均一温度、镜质组反射率、孢粉颜色指数、热解分析、有机酸、X-衍射分析、普通薄片、扫描电镜、铸体薄片等资料分别划分了各构造单元的成岩阶段。结果表明,徐家围子断陷深层的成岩作用具有"隆起区较强、坳陷区较弱"的成岩规律,断陷中部的隆起区抬升剥蚀幅度大、地温梯度高、时代相对较老,成岩作用强;断陷两侧的坳陷区抬升剥蚀幅度小、地温梯度低、时代相对较新,成岩作用弱。储层的成岩作用对致密储层的含油气性具有明显的控制作用,砂岩、砾岩工业气层的勘探下限分别为中成岩阶段B1亚期和晚成岩阶段A期对应的深度。

In order to understand diagenetic regularity and impact factors of the deep Xujiaweizi fault depression in Songliao basin, and their controlling over gas-bearing capacity of compact reservoir, this study focused on classification of diagenesis and discussed diagenetic features of each structural unit using fluid inclusion homogenization temperatures, Ro, TAI, Rock-Eval, organic acids, XRD, thin section, SEM, blue epoxy resin-impregnated thin sections. Results show that the Xujiaweizi fault depression is characterized by diagenesis intense in uplift and weak in depression. Compared with both areas on both sides of the depression, the central depression has high magnitude of uplift exhumation, high geothermal gradient, older formation and weak diagenesis. Oil- and gas-bearing capacity of the tight sandstone is obviously controlled by reservoir diagenesis, and bottom limits of gas exploration in sandstone and conglomerate beds responds respectively to depths of the middle stage （B1） of and late stage （A） of diagenesis.