| Development practice of Weixinan Depression shows that the complexity of L1 reservoir distribution with multi-source,great change longitudinally and transversally,bad continuity of sandstone body,strong heterogeneity,well production is characterized by rapidly rising of the gas-oil ratio,poor connectivity,reducing the oil production greatly and low flow potentia,l slow water injection response。If being dependent on offshore Conventional Evaluation Technique,it is difficult to built up reasonable geological mode guiding field development。So it is need to strengthen working depth of servoir evaluation,develop suitable evaluation technique and Development tactics,built up dependable evaluation and development model,it provides the reference for developing economically and efficiently similar reservoirs,It is of important significance to start up the development of similar reservoirs at the same time.This paper studies L1 of WZ11-1N, which is the structural and lithologic reservoir, we synthetically use the data of seismic, core, log, production test and production performance of developed well, evaluate the reservoir, build reservoir parameters modeling, confirm lithology-electric property-physic property-oil-bearing relationship. We do high resolution sequence stratigraphy contrast of single well and well tip using the sequence stratigraphy principle, confirm sedimentary characters by logging facies and seismic facies, recognize superimposed relationship and transverse distributing of sand body by seismic-lithology inversion. All above, we do geological modeling and geological synthetical evaluate to know reservoir heterogeneities and reservoir connectivity, recalculate OIP of L1, build the modeling fixing the reservoir and make the economical and high efficiency develop plan.The results show that:(1)the reservoir quality increases with grain size. Relatively coarser grained sandstones have better quality than fine-grained sandstones. Criterias for identifying the cutoff of reservoir in study area are as follows:siltstone,oil patch,porosity of 13.6%,permeability of 1×10-3μm2,muddy content of 15% and oil saturation of 40%. Base on the character of oil reservoir in L1 segment, the author divided them into three types;(2) Systematic analysis concludes that the heterogeneity of lithology and reservoir quality (in form of porosity and permeability ) exerts a dominant influence on hydrocarbon accumulation.①Seismic facies shows that the sources of L1 segment clasts derive from the southern uplift. According to the morphology and distribution of sand body,it can conclude that the reservoir sandstones of L1 segment were deposited in fan delta system with distributary channels widely distributing. The sandstones of main stream channels generally develop in the middle of the structure,which have the best oil/gas-bearing nature.②The depositional environment during L1 segment is fan delta system. The framework sandstones are maily developed in subaqueous distributary channels of delta front subfacies,secondly in mouth bars and sand sheets. In contrast, the reservoir quality of subaqueous distributary channel are of the best among all kinds of sandstones in the fan-delta microfacies,mouth bars are of better and the sand sheets are of the worst;(3) Through above study,detailed geological modeling was carried out,in the method of inversion-controlled lithofacies modeling. Making corresponding development policy based on reservoir heterogeneity to be the point,and finally there is a perfect application on the basis of analysing practical example.
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