Abstract: After reservoir fracturing,it is easy to form elliptic seepage field around two wings of the wellbore.Based on this mechanism,by acquiring the start-up pressure gradient and the fracture azimuth of low permeability reservoirs,the radius of pressure relief can be determined.And therefore,the well pattern,well spacing and row spacing which fully control the hydrocarbon reservoirs can be obtained.With this method,the drainage radius of Lengxi oil reservoir has been determined and the new development well location has been deployed.This method can not only effectively solve the problem of great difficulty in controlling reserves of low-permeability oil reservoir with regular well pattern,but also has a certain guiding significance for the determination of later water injection parameters.