Research Of Reservoir Characters, Classification And Evaluation Of Laojunmiao Paleogene System L Reservoir

Laojunmiao oil field locates in the middle of Laojunmiao anticline belt in JiuxiBasin, which is the earliest use of modern technology to develop oil fields. The field has 70 years of development history since 1939, and leaves us with a lot of valuable information and experience. But with the increase in the development period, the situation underground became more complicated and the development of reservoir became more difficult. In order to maintain stable oil production, the paper chose Laojunmiao L reservoir as the research target. With geology, core logging, laboratory analysis, and the development of dynamic analysis, Layer of fine-grained comparison group, microfacies, four property relationships, characteristics and classification were studied. With further understanding of reservoir geological characteristics, these studies lay a solid foundation for reservoir water flooding further adjust and extend the oilfield EOR vitality.According to LaojunmiaoL reservoirlayered sandstonereservoir characteristics, and the former researchresults, L reservoir was classificated and correlated with the layer identification and the "combination of well and seismic, cycle control, classification comparison" principle. The L formation was divided into 5 layers and 15 sublayers, which were named L1, L2, L3, L4, L5. The isochronous stratigraphic frame was established. The results corrected the channeling layer problem caused by the unified comparison previously and determined L4+5 formation developed in the whole region, but sand body developed in the western and pinchout in the eastern reservoir. Based on theestablishment of stratigraphic framework,through the research of regionaltectonic movement and sedimentary background,theLaojunmiaoL reservoirsourcewas determined to come from thesoutheast. Sedimentary system distributed from southeast to North West. With the help of coring wells, standard logging facies were established, and reservoir L was considered as braided river-braided river delta sedimentary system, where braided river,braided delta plain,braided riverdelta front subfaciesdeveloped. The sedimentation type of L3, L4, L5 layers were braided river, L2 was delta plain, and L1 was delta front facies. Through the study of sedimentary facies and sedimentary microfacies type, the deposition model of L reservoir facies was established, showing temporal evolution characteristics of Laojunmiao L formation sedimentary system. With the analysis of reservoir petrology characteristic, reservoir four property relationship was studied. The L reservoir lithology had greater impact on reservoir properties, and porosity had a better correlation with permeability. Through the research of relations among reservoir lithology, physical property, electrical property and oil-bearing property, the interpretation model was established, and gotthe overall understanding ofreservoir from thecoring well.Research on reservoir characteristics showed that the reservoir rock type was relatively single, mainly quartz sandstone. Cements are complex, mainly calcareous and argillaceous, and types are complex especially the montmorillonite, illite and calcite. L reservoir space was mainly intergranular pores, belonging to the high permeability and high saturation reservoir. L3 layer had the best property among the three mainlayersand L1 wasthe worst, which has fine lithology, high shale content and low permeability. Using the physical properties and pore structure as the classification parameters, classification standard was established, and the L reservoir was divided into three categories. With the analysis of the new integrated coring wells and the dynamic development of new drilling wells, producing condition was analyzed for three kinds of reservoir. Part of class Ⅱ and class Ⅲreservoirs will be the next focus on tapping the potential of the target reservoir.