The Study Of Fracablity And Correspond Fracturing In West Gaotaizi Reservoir

The thin oil reservoirs in the old oilfields have many small layers in the longitudinal direction,thin interlayers,and large differences in physical properties between layers.There are large differences in the development of sand bodies on the plane and serious heterogeneities.Therefore,the contradiction between layers and the plane conflict cause poor results in waterflooding development,and the remaining reserves are difficult to tap.The high platform oil layer in the western part of Central District contains a number of thin-difference oil layers,which have poor physical properties and low percolation.They can only rely on stratum energy and water flooding to produce industrial oil flow.It is necessary to increase stimulation measures such as fracturing and acidification in order to have a certain capacity..Therefore,it is necessary to have a clear understanding of its reservoir properties so that targeted development plans can be formulated,effective stimulation measures and enhanced oil recovery technologies can be adopted,and scientific and rational development can be carried out to achieve good development results.In this paper,the west gaotaizi reservoir is taken as the research object,based on the combination of rock mechanics parameters and reservoir physical property parameters measurement and theoretical analysis.By using the parameters of brittleness index,fracture toughness and tensile strength,the reservoir compressible properties are evaluated.Based on the experimental data of electrical simulation,the increase ratio of different geological characteristics,different injection production wells and fracturing scale is measured,and a comprehensive analysis is made for the increase of yield and effect of reservoir fracturing.The optimization method of fracturing fracture parameters is corresponding to the mining well.The research methods and knowledge are as follows:(1)Experiments such as triaxial compression and brazilian cleft were carried out to determine the mechanical parameters of the high-thin subsidence reservoirs in the western part of Central District.The results show that the Young's modulus of the target zone is between 3.5?60GPa,with an average of 31.5GPa;the Poisson's ratio is between 0.21?0.39,the average is 0.28;the brittleness index is between 0.11 and 0.62.The average brittleness index is 0.31;the fracture toughness is distributed between 0.05 and 0.18,and the average fracture toughness is 0.155.(2)A comprehensive evaluation method for compressibility was established.The influence weight of each factor was calculated using the analytic hierarchy process method.The weight coefficients of brittleness index,fracture toughness,and tensile strength were 0.53,0.29,and 0.18,respectively.Based on statistical logging data,a map of the compressibility distribution of the Gaotaizi oil reservoir group in the west of the Central District was obtained,providing the basis for fracturing well selection.(3)Conduct electric fracturing electric simulation experiments on the target block to optimize the fracture parameters of the corresponding fracturing.The experimental results show that the optimal combination of fracturing scales for a fracturing group is:fracture penetration ratio of oil wells is 25%?30%,crack penetration ratio of wells is about 15%,and the corresponding pressure of the anti-nine point well group is The optimal fracturing scale combination for cracking is:the fracture penetration ratio of oil wells is 55%-60%,and the fracture penetration ratio of wells is 10%-15%.