The Research On Comprehensive Evaluation And Reservoir Characteristics Of Shuangyang Formation Luxiang Faulted Depression, Yitong Basin

Yitong basin located at the south of Yitong graben, Yitong basin include Moliqing fault depression Yidan upthrust Luxiang fault depression and Chaluhe fault depression four secondary building units. Luxiang faulted depression include Danan depression Wuxing structural belt.The paper based on drilling core observe,microscope identification,well logging and seismic data analysis and mercury penetration experimentation measure etc, do the study of reservoir sedimentary facies,the feature of distribution,the type of air space,pore configuration,reservoir physical property,the type of diagenesis,diagenetic stage and diagenetic evolution model, then made a research on mathematical statistics by choosinge the key parameters which were intimatly related to develope feature and evaluation of reservoir.The main sedimentary facies are fan delta face and lake face in Shuangyang formation of this area, including eleven subfacies,sixteen microfacies.In the first member layers Shuangyang formation, eastern provenance,northern provenance and southwestern provenance vegetation fan delta; southeastern provenance of basin vegetation subsea apron;center of basin vegetation lake facies. In the second member layers Shuangyang formation, eastern provenance,northern provenance and southeastern provenance vegetation fan delta; fan delta plain scale is greater. Lake facies did not vegetation.In the third member layers Shuangyang formation, southern provenance and northern provenance vegetation fan delta. Northern provenance vegetation three fan delta ,fan delta plain and front did not vegetation ;southern provenance vegetation three fan delta and vegetation fan delta front ,but plain did not vegetation.Based on analysis of lithology characteristics, make sure that the reservoir rocks is arkose,lithic arkose and arkose quartzite, the fuller is mainly mud,carbonate mineral,autogeny quartz and clay mineral. According to the research of sandstone diagenesis, have induction that the diagenesis of reservoir are machine compaction,cementation,carbonate cemented and metasomasis,denudation and clay mineral transform acting etc. And the denumation is the main diagenesis in this area. Diagenetic stage divide into early diagenetic A,B sub-stage and late diagenetic A,B sub-stage. Late diagenetic Asub-stage is the main diagenesis sub-stage.The airspace type of reservoir in Shuangyang formation include two types: primary pore and secondary pore, the primary pore include intergranular pore and micropore, secondary pore include emposieu and fracture pore. The analysis of mercury penetration experiment characteristic parameter indicate that : the pore configuration in the first,second and third member layers Shuangyang formation is under middle (ⅡB),up middle (ⅡA) and sub-bad(ⅢA).Based on core test data analysis and mathematical statistics, established the forecast relation between porosity,permeability and acoustic travel time equation of linear regression,the result display: physical property of Shuangyang formation the second member layer reservoir is relatively better,the average value of porosity is 14.14%; the average value of permeability is 40.335×10-3um2,the type of reservoir is low porosity mid permeability. Physical property of Shuangyang formation the second and third member layers is relatively worse, is low porosity low permeability. According to the analysis of correspond relations between microfacies and physical property, from under water distributary channel,mouth bar to sand sheet ,the physical property become more and more worse.Based on research result of above-mentioned, choose ten parameters of physical property,lithologic character and pore configuration, and use obscure synthesis on reservoir evaluaterating. according to the contribution of reservoir evaluation, assign different quantity. According to the results of obscure synthesis on reservoir: the first member of Shuangyang formation ,which evaluated value was 0.621,is the better reservoir of typeⅡ1;and the evaluated value of the second and third member layers is 0.443 and 0.431,it belongs to the type of worseⅢ.