Study On The Brittleness Characteristics Of Tight Sandstone Reservoir Of ShanXi1 Member In SuiDe-WuBu Block

In this paper,the tight sandstone reservoir of the Shanxi1 membe in Sui De-Wu Bu area in the east of ordos basin is taken as the research object,based on the theories and methods of mineral petrology,rock mechanics and geophysical logging,the study on the material composition,structure,rock mechanics and brittleness of the sandstone reservoir in the first member of the target area was carried out systematically.Based on the mechanical experiment and well logging interpretation,this paper conducted a quantitative study on the dynamic and static transformation analysis of rock mechanical parameters.Based on the rock mechanics parameters,the brittle continuity evaluation model of single well is established,and the influencing factors of reservoir brittleness are discussed.Based on the XRD experiments,SEM analysis and thin section identification,it is concluded that the sandstone reservoir of shan 1 in the study area is rich in quartz and cuttings,and lacks feldspar,and the rock types are mainly lithic quartz sandstone and lithic sandstone.The average content of brittle minerals is 72.3%,dominated by quartz,and 20%by clay minerals,dominated by illite.The average porosity of sandstone is6.19%?10.18%,and the average permeability is 0.1578×10^-3?m²?0.5146×10^-3?m²,which is a tight sandstone reservoir with low porosity and low permeability.Uniaxial stress tests were carried out on the tight sandstone samples in the first member of the mountain in the study area to obtain the static rock mechanical parameters such as poisson's ratio,young's modulus and compressive strength;The longitudinal wave time difference and rock density parameters extracted by conventional logging are calculated with the empirical formula to obtain the dynamic rock mechanics parameters;The transformation relations of dynamic and static young's modulus,poisson's ratio and compressive strength were established,and the rock mechanics parameter profiles of 6 single Wells in the study area were established based on logging data.The results showed that the poisson's ratio and young's modulus of the tight sandstone reservoir in shan 1 were mainly between 0.2-0.5 and 10-60 Gpa.Through the rock mechanics parameters to calculate the brittle index of the reservoir,combined with the rock mechanics parameters of single well section,single-well brittleness continuity evaluation,and analyze the factors such as reservoir mineral composition and physical properties of the influence of brittleness,think rigid detrital mineral content is higher,low plastic mineral content,good reservoir physical property has high elastic modulus and compressive strength,namely has great brittleness index.Combined with the production examples in the research area,to evaluate the frac ability of reservoir was based on the rock brittleness and put forward some suggestions on the optimum selection of frac section.There are 62 figures,14 tables and 83 references in this dissertation.