Study On Fluid Properties And Fracture Identification Method Of Tight Sandstone Reservoir In The Second Member Of Xujiahe Formation In Western Sichuan Depression By Using The Logging Data

As an unconventional oil and gas resource,tight sandstone gas plays an important role in the field of oil and gas resources in China and even the world.However,due to the poor physical properties and strong heterogeneity of tight sandstone reservoirs in the study area,it is very difficult to explore and develop them,and it is also very difficult to carry out research on fluid property discrimination and fracture identification methods.Therefore,it is of great significance to carry out research on fluid property discrimination and fracture identification methods in the study area.In this paper,the tight sandstone reservoir of the second member of Xujiahe Formation in the A gas field of the Western Sichuan Depression is taken as the research object.The reservoir characteristics of the study area are analyzed according to various data such as rock slices and core porosity and permeability experiments.On this basis,conventional logging,array acoustic logging,electrical imaging logging,gas testing,gas logging and other data are used to carry out research on the fluid property discrimination and fracture identification methods in the study area.Firstly,the petrological characteristics and physical properties of the reservoir in the study area are analyzed by using rock slice data and core porosity and permeability experimental data.Then,the conventional logging response characteristics of different fluid reservoirs in the study area are analyzed.On this basis,the porosity logging and resistivity crossplot method,three porosity difference and ratio method,Poisson ’s ratio and volume compression coefficient overlap method and normal distribution method are used to study the reservoir fluid property discrimination method in the study area.The fluid property discrimination effect of the normal distribution method is better,and the fluid property discrimination accuracy reaches 83.3%.Finally,according to the core description,electrical imaging logging and conventional logging data in the study area,the fracture identification method is studied.The core observation method and electrical imaging logging are used to identify the fractures of the reservoir in the study area.Then,based on the analysis of the conventional logging response characteristics of the fractures,the microsphere focusing resistivity change rate method,the reconstruction characteristic parameter method and the logging curve reconstruction method are used to study the conventional logging fracture identification method in the study area.The logging curve reconstruction method proposed in this paper has achieved good application results in the study area,and the accuracy of fracture identification reaches85.62 %.