Study On Productivity Evaluation Technology Of Low Permeability Tight Reservoir

In recent years,with the general improvement of people's life quality around the world,h?man daily life is increasingly inseparable from the demand for energy,especially oil and gas,which is a kind of high-quality resource,has become a necessity of h?man life.The accurate prediction of oil and gas field production capacity can not only evaluate the early stage of oil and gas field development,provide reliable development basis,but also have a great influence on the layout of well pattern,the development of reservoir oil and gas and the economic benefits of oil and gas wells.With the development of global oil and gas fields,the proportion of low permeability reservoirs is higher and higher,and the development difficulty is becoming more and more difficult.In order to accurately predict the reservoir capacity of oil and gas fields,the following research work is carried out in this paper.In this paper,a block of a large oil and gas field is taken as the main research object.Based on the conventional physical property data,test data,logging data,mercury injection data,rock electrical experiment data,combined with gas-water permeability and thin section identification information,the reservoir characteristics,micro pore structure characteristics and logging response characteristics of the study area are analyzed.After the data analysis,it is found that the research area contains a certain proportion of micro pores,which is very complex in pore structure and poor in physical properties of reservoir,which makes it difficult to calculate reservoir parameters and predict reservoir productivity.Therefore,on the basis of previous studies,the calculation model of porosity and shale content based on optimization theory,permeability calculation model based on flow unit index(FZI)reservoir classification and variable m-value water saturation calculation model based on high temperature and high pressure rock electrical parameters are established.Based on the shape of capillary pressure curve and FZI classification of reservoir types,the lower limits of reservoir physical properties are studied by porosity and permeability relationship method,empirical statistics method,maxim?m curvature radius method,minim?m flow pore throat method and cross plot method.The lower limits of porosity,permeability,shale content and gas saturation are 7.29%,0.29 md,38% and 40%.Finally,according to the basic theory of productivity prediction,the relationship between the meter gas production index and the productivity influencing parameters is analyzed.The main influencing factors of reservoir productivity in the study area are water saturation,porosity,shale content and effective permeability.The comprehensive evaluation index prediction model of productivity is established,and the meter gas production index predicted by the prediction model is compared with the actual meter gas production index.The results show that the predicted results of the model are in good agreement with the actual test productivity,the relative error of the model is small,and the coincidence rate is about 80%.Therefore,the model can be used as a productivity evaluation method in the study area,which provides an effective technical basis for gas field development in the study area.