Abstract
During a hydraulic fracturing treatment, the injected fracture fluid usually leaks off into the formation around the fracture to some degree. This leakoff results in absolute and relative permeability reduction around the fracture. This dissertation summarizes a study of the fracture fluid cleanup behavior and well production performance after a fracture treatment and presents, in more detail, new methods to analyze well test data for hydraulically fractured wells. The research originated from the observation that poor fracture fluid cleanup might help explain disappointing well production performance for certain hydraulically fractured gas wells. We studied both single- and multi- layer gas reservoirs and we identified factors associated with gas production and fracture fluid cleanup in low-permeability, low-pressure reservoirs. We found key factors which dominate fracture fluid cleanup and gas production behavior. We also discuss possible incorrect simplifications for multilayer, anisotropic reservoirs. The major effort in this study was to develop new solutions for finite conductivity fractures including wellbore storage and fracture-face skin damage. The infinite conductivity fracture solution is included as a limiting case. The new solutions are obtained numerically by modeling a general elliptical wellbore in an elliptically-composite reservoir, including the effects of wellbore storage and infinitesimal fracture-face skin. The new solutions agree with analytical solutions. The time span studied (dimensionless time to) was from 10^-8 to 10^5. These new solutions provide new perspectives for finite conductivity fractures with wellbore storage and fracture-face skin. Both pressure and pressure derivatives are presented in type curves. New techniques, which are based on the new solutions, were used to analyze post-fracture welltest data. We could not analyze these data accurately with published solutions. The solution techniques presented here are directly applicable to all elliptical flow problems...
Liao, Yizhu (1993). Well production performance and well test analysis for hydraulically fractured wells. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1474638.