A comprehensive overview on recent developments in refracturing technique for shale gas reservoirs

Refracturing is described as hydraulic fracturing the formation which has earlier been hydraulically fractured. Presently, it is among the most widely used restimulation techniques. The technique to refracture the wells which are less productive and having poor reservoir quality has been applied since 1940s. The perception, however, is that refracturing technique is generally unsuccessful. But with the recent advancement in technology and improved refracturing techniques, many operators have now successfully implemented this technique for not only poor but also good quality reservoirs to increase production rate and to enhance ultimate gas recovery from shale gas wells. It also serves as countermeasure against the declining rate of gas price, because refracturing operation is less costly compared to drilling and completing a new well. Refracturing operation, in general, is a complex process. Additional research and development is needed for its successful implementation and higher reliability. This paper explores the attributes responsible for successful refracturing treatment and conditions limiting the application of refracturing treatment. Furthermore, it presents the procedure for candidate well identification and discusses the refracturing treatment design, treatment diagnostic techniques and economical evaluation of the treatment. In addition, it also highlights the challenges for refracturing treatment. It also presents two case studies to support the concept and demonstrate recent developments. The paper provides significant insight into the refracturing technology and the guidelines for its successful application in shale gas reservoirs.