Performance Prediction of Refractured Wells Based on Embedded Discrete-Fracture Modeling Method

Abstract

In unconventional reservoirs, the production rate of the initially fractured well will decrease rapidly as the development proceeds. In order to maintain economic well productivity of the initial fracture, the industries can create refractures to prevent the well production rate from decreasing. However, the production of the initial fracture can induce the stress field to reorientate, which will cause the refracture to propagate along a different direction from the initial fracture. Thus, the refracturing treatment can result in a complex fracture system which raises a stringent challenge for one to evaluate the performance of the refractured well. In this paper, the authors utilize the embedded discrete fracture model (EDFM) to characterize the performance of the refractured wells. The calculated results in this paper show that, for the same equivalent matrix permeability, a larger permeability component parallel to the initial fracture can lead to a higher increase ratio of the refracturing treatment but lower cumulative production. If the reoriented section of the refracture is orthogonal to the initial fracture, the productivity of the refracture system can be the highest. The length of the reoriented section plays a more important role than the length of the initially oriented section in influencing the refracturing treatment. The refracturing treatment can lead to a higher increase of cumulative production if the initial fracture has a lower permeability.