An integrated study of cleanup efficiency of short hydraulic fractured vertical wells using response surface methodology

Abstract

In tight gas reservoirs, gas well production is impaired after Hydraulic fracturing, that is mostly due to fracturing fluid (FF) invasion into matrix and fracture and poor clean-up efficiency. The scope of this study is to investigate the clean-up efficiency in short hydraulic fracture vertical wells and observe how the effect of pertinent parameters on gas production loss (GPL) changes with the hydraulic fracture length. The impact of 12 parameters including fracture permeability, matrix permeability, End point and Exponent of Corey gas and FF relative permeability curve in both matrix and fracture, and Interfacial Tension and Pore Size Index (capillary pressure) have been studied by developing a computer code. Interactive linear surface model describing the dependency of GPL to the pertinent parameters was used. The results indicate that as fracture length decreased the effect of fracture parameters (fracture permeability and End point and Exponent of Corey gas and FF relative permeability curve in fracture) on GPL decreased and the effect of those relevant parameters in matrix on GPL increased. The effect of capillary pressure in reducing GPL is less pronounced in shorter fractures. In shorter fractures, faster fracture clean-up was observed compare to the one for longer fracture.