Production performance of horizontal wells with dendritic-like hydraulic fractures in tight gas reservoirs

Abstract

Nowadays horizontal wells, combined with hydraulic fracturing technology, have been widely used to produce tight gas at an economic rate. The production performance of the horizontal well can be predicted by analytical or numerical models. In most models, the horizontal wells are assumed to be fractured by bi-wing fractures. However, recent micro-seismic measurements depict a dendritic-like morphology of hydraulic fractures in tight gas reservoirs. This indicates the conventional fracture models are sometimes inapplicable for tight gas simulation.In this paper, a modified off-center well model was coupled in the discrete fracture model (DFM) to predict the production performance of dendritic-like stimulated horizontal wells. Finite volume method was used to discretize the partial differential equations, and the linearized equation system was solved iteratively in a fully implicit scheme. The off-center well model was verified against ECLIPSE. A field case of multi-stage fractured horizontal well from a shale gas reservoir was studied.In addition, the effects of some fracture geometric parameters (e.g., fracture angle, fracture asymmetry and fracture branch number) on well production were investigated in detail. Results show that fracture angle has high relevance to the production performance in that cumulative production tends to be higher with more evenly distributed angles. Fracture asymmetry seems to have little influence upon the production. Fracture branch number has a strong influence on enhancing gas production, but the influence becomes weaker with increasing branch number. This paper provides us a better understanding of dendritic-like fractured gas reservoirs.