Resrvioir Character Regularity Of Chang6Oil-bearing In Zaowan Area Of Zi Chang Oil Field

The sandstone of Chang-6oil-beairng in Zaowan area is typical low permeabilityreservoir which is the research focus today. It’s important to expolre the area effectively thatfinding the favorable exploration block basing on reservoir descirption and evaluation.By virtue of multiple expeirmental testing method and vairous data analysis, we conducta comprehensive analysis of reservoir lithology, pore throat structure, percolationcharacteirstic and reservoir heterogeneity rfom small layers division, classiifcation ofmicrofacies and research of the sandbodies distirbution. Next, select reasonable mainparameters to conduct comprehensive reservoir evaluation,and then using the test data topredict the single well production capacity，finally divide the favorable reservoir zones bycomprehensive analysis of reservoir evaluation results and productivity prediction results. Theresults are as follows:1.Make use of logging data, we make division and correlation of substrata in Zaowanoil layer. On the basis of detailed strata framework in research region, and atfer makinglogging fades analysis, the distirbutary channel, the interdistributory channel，the underwaterdistirbutary channel, the interdistirbutory bay are identiifcated.2.Reservoir rock types in the study area was ifne-grained feldspathic sandstone. Detirtalcomponents arc feldspar mainly, followed by quartz, lithic and mica. Interstitial mateiral ismainly calcite，chlorite, followed by the laumontite. Rock is more dense, and detrital grainswere once the main round? subangular, sub-degree chosen medium-good relations, withlinear contact and pore cementation mainly.3.The Chang6reservoir has entered late diagenetic stage. The diagenesises of Chang6reservoir are mainly compaction, pressure solution, cementation, metasomatism, dissolutionand transformation of clay minerals, such as recrystallization. The greatest diagenesisesimpacting on reservoir porosity are compaction-pressure solution, cementation anddissolution. 4.The major reservoir space of Chang6is pirmary intergranular pore and secondaryporosity, pore type is mainly feldspar dissolved pores, followed by intergranular porosity,grain bore.5.Combined with reservoir properties in this area, macroscopic features of reservoir space,microscopic pore structure characteristics, capillary pressure curves and reservoir thickness,Hthology, Chang6reservoir has three types: III (III b sub-categoires), IV (IV a，IV bsubclasses), V categories，is a low porosity-special permeability reservoir to the hole-thinthroat pore throat portfolio based.6-The oil accumulation has a multi-layered reservoir development features supeirmposedon the longitudinal plane northwestern developed well in the southeast.