Evaluation Of Reservoir-permeability Unit Of Shuang3 Block In Shenmu Area

Evaluation of Reservoir-permeability unit is important to predict oil and gas reservoirs,which can be researched to effective understand the heterogeneity of oil and gas reservoirs.The study can analyze the distribution of remaining oil and provide some suggestions and guidance for the subsequent dynamic exploitation of oil and gas fields.The main content of this paper is to evaluate and research the Reservoir-permeability unit in the Shuang3 block of Shenmu area in the Ordos Basin.Shenmu gas field is a typical representative of low permeability-low abundance gas reservoir.By combining with the geological characteristics of the study area and researching Partition Method of Reservoir-permeability unit at Home and Abroad,this paper selects two methods of cluster analysis to divide Reservoir-permeability unit in the Shanxi-Taiyuan formation reservoirs.Compare the results of two methods.then,choose the results of the support vector machine as the final result and build the 3D Reservoir-permeability unit model.The following research results are mainly obtained:1.The marker layer method is used as the method of stratigraphic division and contrast.Two sets of coal seams developed in the whole study area are selected as the main marker layer,and the stable and widely developed camel neck sandstone is used as an auxiliary marker layer to establish a link profile.23 contrast profiles are established,thus creates a stratigraphic framework of small layer contrasting.2.The results of the comprehensive analysis of the coring well data,drilling data and predecessors' understanding indicate that the source direction of the Shanxi-Taiyuan Formation in the study area is north-northeast.On the basis of stratigraphic division,regional geological background,sedimentary environment and source supply direction,,the sedimentary facies type and distribution pattern of Shanxi-Taiyuan Formation reservoir in Shuangsan block of Shenmu gas field are determined by using coring well data and logging curve characteristics.According to the study,the sedimentary facies of Shanxi-Taiyuan in the study are delta plain,and there are mainly three kinds of microfacies: the distributary channel microfacies,the distributary depression microfacies and the marsh microfacies.Among them,the distributary channel microfacies is dominated by sand deposits due to the action of rivers,and the sediments of the distributary depression microfacies are dominated by mudstone deposits and coal deposits.3.Through the optimization of various parameters,the porosity,permeability,shale content,gas saturation and deflation radius were eventually selected as the parameters to divide Reservoir-permeability unit into three types of Reservoir-permeability unit by two methods of clustering analysis.The accuracy of the two methods is verified by comparing the results with the manual ones.Finally,the support vector machine with higher coincidence rate is selected as the optimum selection method of reservoir,and the plane distribution of Reservoir-permeability unit is determined.4.The sedimentary microfacies model is established by multipoint geostatistics simulation,and then the physical property model is established by sequential Gaussian simulation on the basis of the sedimentary microfacies model.Finally,the Reservoir-permeability unit model is established by using sequential indicator simulation and taking sedimentary facies as constraint condition.