Evaluation Method for Efficiency of Primary Fracture in Refracturing

When estimating productivity of refractured well,the primary fracture is considered to be disabled and it is not coincident with actual facts and a great error of prediction result exists.Therefore,a mathematic model and corresponding solution numerically solbing method,for efficiency appraisal of fracture and productivity estimations,are provided in this paper.Based on post-refracturing production data and water cut,considering that only primary fracture exists,its efficiency is coupled by adjusting parameters.The productivity of refractred well is further calculated taking account into the interaction of refractured fracture and primary productivity and meanwhile the efficiency of primary fracture is validated.