Numerical simulation on overall fracturing of fault block Tai 27 in Wuliyasitai Oilfield

Fault block Tai 27 in Wuliyasitai Oilfield is a typical low-permeability oil reservoir, and it has a certain production capacity after fracturing stimulation. To optimize the overall fracturing parameters of fault block Tai 27, history matching of production wells was carried out by means of numerical simulation to verify the reliability of non-Darcy flow model with starting pressure gradient and mathematical model of overall fracturing. Then, the overall fracturing design of inverted nine-spot well pattern in fault block Tai 27 in Wuliyasitai Oilfield was optimized. The effects of fracture length ratio and conductivity on oil well productivity were analyzed. Development schemes for different combinations of fracture parameters were designed and optimized by using the orthogonal design method. The simulation results show that the fracture parameters suitable for fault block Tai 27 are as follows. The fracture semi-length in well injectors is 44 m. The conductivity is 10 D·cm in well injectors and 20 D·cm in corner wells. The ratio of fracture length to distance between wells is 0.3 (semi-length of fractures 66 m) in edge wells and 0.45 (fracture semi-length 99 m) in corner wells. It is indicated that in a given well pattern, there is an optimal fracture length and an optimal conductivity, but the highest may not be the best. The researchresults can be used as the reference for the overall fracturing of other low-permeability oil reservoirs.