Reservoir Description And E&P Strategy Of Chang4+5and Chang6in Shijia Area, Qingpingchuan Oilfield

With the improvement of geological knowledge and exploration level, the explorationwork of Chang4+5and Chang6reservior get a breakthrough in Shijia area of Qingpingchuanoil field, and some fields have been put into development. Due to the overall degree ofexploration is low, and the geological and test data is limited, the process of exploration anddevelopment appeared some problems to be solved, the further work of exploration anddevelopment in this area is limited.Such as oil and gas enrichment regularity is not clear, theinitial production is very good but decreasing quickly, the water in part of oil well risingquickly. Based on the analysis of drilling, logging, well logging and core data of the oil fieldand comprehensive use of cast slices, scanning electron microscope, mercury injection, grainsize analysis, core analysis technology, the reservoir sedimentary facies, lithology and physicalproperties of this field were studied, finally the geology model is established. The reservoirenrichment regularity is summarized and analysised; At last, combined with the feature ofproduction performance, put forward the suggestion of exploration and development of thisarea.The conclusions are as following:(1) The result shows that the sedimentary facies of Chang4+5and Chang6reservior inthis area is delta sedimentary, sedimentary subfacies is delta plain sedimentary，sedimentarymicrofacies are distributary channel and interdistributary bay sedimentary，sand bodies aremainly delta plain distributary channel sand bodies，and the direction is NE-SW direction.(2) Chang4+5and Chang6reservior in this area have a single stable source，reservoirlithology is mainly feldspar fine sandstone，contains a small amount of siltstone. Point-linearcontact is the mainly contact relationship, cementation types is quartz overgrowth and chloritepore filling, the average pore diameter is28.3μm, the average throat radius is0.132μm,porestructure is medium hole with microthroat, The average porosity of Chang4+5reservior is9.8%, the average permeability of Chang4+5reservior is0.32×10-3μm2, The average porosityof Chang6reservior is9.6%, the average permeability of Chang6reservior is0.28×10-3μm2,itBelongs to the low porosity and low permeability reservoir. (3) The3D visualization geological model of the study area is established, Includingstructural model, sedimentary microfacies model, property model and grid graph model,through geological data and production performance data validation, accuracy of this model ishigher and in accordance with the geological situation.(4) The oil and gas enrichment of this area is mainly affected by sedimentary facies andreservoir property, favorable reservoir facies is delta plain distributary channel sand body,wells that located in the main channel have better properties, the test oil yield is higher.According to the geological model and oil and gas enrichment rules,we can determine ninefavorable areas, deploy five exploration wells; through the analysis of productioncharacteristics and reference of neighbor area,we find that this area is suitable for the irregularinverted nine spot well pattern or irregular inverted seven spot pattern water floodingdevelopment, developed regions for synchronous water injection, undeveloped area foradvanced water injection.