大民屯凹陷成岩作用定量表征及有利区带预测

Quantitative Characterization Of Diagenesis and prediction of favorable areas in the Damintun Depression

储层实测孔隙度、普通薄片、铸体薄片和扫描电镜的资料表明,大民屯凹陷新生界储层在纵向上发育三个次生孔隙带。从而在一个普遍低孔渗背景下,形成了孔隙度相对较高的优质储层。优质储层的形成和分布主要受沉积微相和成岩作用的影响与控制。他们形成于河道、泛滥盆地、三角洲平原、三角洲前缘水下分支河道、河口坝席状砂及扇三角洲平原和前缘等相带,目前处于早成岩阶段B期~中成岩阶段A1亚期,发育溶蚀成岩相。该文通过成岩作用定量表征方法,预测了大民屯凹陷成岩阶段和成岩相的横向展布。通过成岩相图和沉积相图的叠合,预测了沙三四亚段优质储层的分布。预测结果表明,优质储层主要发育于凹陷东北部地区。

There exist three secondary porosity zones vertically in the Cenozoic reservoirs of the Damintun Depression as measured porosity data,thin sections,blue epoxy resin-impregnated thin sections and scanning electron microscope suggest.As a result,the high-quality reservoirs are developed.Sedimentary microfacies and diageneses control the formations and occurrences of the high-quality reservoirs,which are dominantly formed in the sandstones of channels,floodplains,delta plains,branch channels and channel mouth bars of the delta fronts,fan-delta plains and fan-delta fronts,little in alluvial fan and shallow lake,located in the early diagenetic stage B～middle diagenetic stage A1 and dissolution diagenetic facies.The diagenetic stages and diagenetic facies are predicted with the reservoir characterization method by modeling the paleotemperature,vitrinite reflectance,sterane isomerization rate and authigenetic quartz concentration in space and time.The high-quality reservoirs of the third forth submember of Shahejie Formation are blocked out by superposing the diagenetic facies map on the microfacies map.They are mainly in the Northeast part of the depression.