Production Performance Modeling of Shale Gas Wells with Non-Uniform Fractures Based on Production Logging

Abstract

Abstract China is the first country achieving shale gas breakthrough outside the North America. Fuling shale gas play is one of the most successful shale gas reservoirs by far in China. However, production loggings in more than ten wells illustrate that only about one third to one half of hydraulic fractures produces. Meanwhile, the productive fractures contribute differently to the production rate. Therefore, models with non-uniform fracture properties like fracture half-length and distance between fractures are needed to model the production performance considering the production logging information. In this paper, Models with non-uniform fracture properties are built to take into the consideration of production logging results. In these models, the fractures can be with un-even distance, un-even half-length while combing specific flowing features of shale gas play like desorption, diffusion and stress dependent permeability. Production logging operations of one case well in Fuling shale gas play are reviewed. In order to honor the production logging results, Interpretation models with non-uniform facture and the ones with uniform fractures are compared. Rate and pressure transient data are used to interprete the formation permeability, fracture half-length and stimulated reservoir volume (SRV) by rate normalized pressure (RNP) method. On the basis of understanding of formation properties from rate and pressure transient analysis and non-uniform fractures properties from production logging, production rate and estimated ultimate recovery (EUR) are predicted by the models with non-uniform fractures for the case well. Results show that only about one third to one half of hydraulic fractures produces and the productive fractures have different contribution to total production rate of shale gas wells. Rate and pressure transient analysis with non-uniform fractures model gets higher formation permeability than the one with uniform fractures model. However, the fractures may have more severe interference between fractures in the non-uniform model and weaken the positive effect of higher permeability on shale gas well's production, or the dominant fractures may affect the less productive fractures adversely. Field applications show that the wells with non-uniform fractures will achieve about 21 percent less EUR than the one with equivalent uniform fractures. Production performance modeling for shale gas wells with non-uniform factures obtained from production logging is the highlight. The research may partly help the design of horizontal laterals and fractures scenarios.