Study on well and layer selection for refracturing in Ansai Oilfield

Deep research on well and layer selection was performed to improve refracturing effect in Ansai Oilfield. Starting with a review of previous refracturing effect, this paper selected these parameters having obvious influence on refracturing effect as the parameters of sample database.Then evaluation method for various parameters in sample database.was presented. Finally sample database of well and layer selection for refracturing was set up in Ansai Oilfield. By the use of fuzzy pattern recognition model, multivariate non-linear statistics method and artificial neural network model, the paper analyzed the sample database separately, and intersection of three results was selected as optimal well and layer. Checked by the testing data, the optimization results are consistent with the actual effect, so the method can be used to direct the well and layer selection for refracturing in the future in Ansai Oilfield.