Establishment Of Discrete Fracture Network Model Of Dina 2 Gas-field In Tarim Basin

In this paper,through the description of core fractures identification and the interpretation of FMI data,analyzing the fractures of the single well in the research area.The result of the fractures' parameters,such as density,aperture,length,dip angle and strike,found that the fracture strike of Dina 2 gas-field is mainly NNW-SSE or NW-SE,and the length of fractures in the core is mostly less than 20 cm.Dina 2 gas-field develops a large number of high-angle fractures and vertical fractures,and some sections of the wells can be seen with reticular seams,the fractures are mainly distributed in the form of en echelon or oblique crossing.According to the relationship between the fractures and genetic mechanism or palaeotectonic stress field,dividing the fractures into large-scale seam,mesoscale seam and small-scale seam.According to the development of fractures in different stratums,lithology and structural areas,analyzing the main influencing factors of fractures development in this area,found that faults,curvature,petrophysical,rock formation's thickness,interbedded structure and lithofacies are the most important factors.The geomechanical method was used to invert and simulate the paleo-tectonic stress field in the study area,and the 3D distribution model of the paleo-stress field in the Dina 2 area was obtained.The fracture development zone was quantitatively predicted,and the control effect of stress on the fracture development was further analyzed.Finally,based on the entropy weight method,the correlation analysis is carried out on various geological factors controlling fracture development and distribution,and the weights of each factor are determined.On this basis,the geological grid model of Dina 2 gas field is established,and the frog tracking technology is used to obtain the fracture distribution of the study area.The fault degree is controlled by fault structure degree,fault scale and genetic mechanism to identify the fault.Articles,26 secondary faults,72 third-order faults,and 14 fourth-order faults,finally construct a fault model.Using the multi-point geologic statistical simulation method and the sequential Gaussian simulation method,the phase control model and the porosity and permeability models of the Dina 2 region were generated in Petrel software.Combined with the fracture parameter properties of the study area,different fracture attribute models are established,and the discrete network model of large,medium and small scale fractures in Dina 2 gas field is constructed.Finally,the Oda-Block algorithm is used to roughen the large-scale fracture network and the small-scale fracture network respectively.Finally,the multi-scale calculation is performed into a property map by using the calculation of fracture properties to realize the synthesis of multilevel fracture network.The two-hole double-permeability model of Dina 2 gas field was established by combining with the model parameters such as porosity,permeability and saturation of the Dina 2 gas field matrix model.