A novel production data analysis method for multi-fractured horizontal wells with infill well-caused fracture interference

Tightening the well spacing for unconventional tight reservoirs is an efficient technique to enhance oil and gas recoveries. Infill well-caused fracture connection between wells is widely reported in the field with small well spacing. This will make it difficult to make formation evaluation and fracture characterization between wells compared to single well cases. In this paper, a novel production data analysis(PDA) method is proposed for fracture characterization with the consideration of interwell fracture connections after the hydraulic fracturing of the infill. The PDA method is based on a semianalytical model, in which the small-scaled fractures are treated with the concept of stimulated reservoir volume(SRV). Thus, the fracture connections between wells are classified into three types, including SRV, fractures, and both SRV and fractures. The physical model is discretized into several linear flow regions, so the mathematical model can be solved semianalytically. An integrated workflow is proposed to analyze the production data for the wellpad, and three steps are mainly included in the workflow, including PDA for the parent well before infill, PDA for the parent well after infill, and PDA for the infill well. In each step, the production performance in the early linear and bilinear flow regimes are analyzed with approximate solutions in the square and fourth root-of-time plots. Because only the relationship between unknown model parameters can be obtained with the approximate solutions, history matching to the production data in log-log plots is further used to determine each unknown parameter. The PDA method is benchmarked with a synthetic case generated by the numerical simulator t Navigator and a field case from Southwestern China. The results show that both good matches and precise parameters can be obtained with the proposed PDA method. The connected fracture number will not be sensitive in PDA when the wells are connected with high-conductive dSRV. The innovation of this paper is that a practical method is provided for PDA analysis of well groups with fracture connection, and it will be a good technique for fracture characterization and well-interference analysis for tight formations.