Abstract
This paper describes the development and use of laboratory data to show the impact of multiphase, non-Darcy flow and gel damage upon gas production from hydraulic fractures. In the work, the percent cleanup is related to the molecular weight and concentration of the gel remaining in the proppant pack and the inertial force available from the flow of gas and liquids during cleanup and production. The impact of proppant permeability and multiphase, non-Darcy flow is further combined with inertial force and gel damage to provide a newly developed relationship to predict the degree of cleanup. The new relationship can be used to calculate the effective conductivity for various proppant types, sizes and concentrations vs. closure, temperature, gel and breaker concentration, and prevailing gas/water/oil ratios. The calculated effective conductivities can then be used to predict gas productivity and economics under various conditions of multiphase, non-Darcy flow.
The results of the testing show that multiphase, non-Darcy flow dramatically increases the difference between the effective conductivities of various proppants and fracturing fluids with different retained permeabilities. The laboratory data and field observations show that when multiphase flow is taken into account, fracturing fluids with high retained permeabilities and premium high conductivity proppants can produce at as much as twice the gas production rate of fluids with 50% cleanup in gas wells producing as little as 10 barrels of water or condensate per MMCF. Using the developed criteria, proppants and fluids can be selected to optimize gas production from wells based upon prevailing reservoir conditions.
