Optimization of Fracture Length in Gas/Condensate Reservoirs

We present an analytical expression for the optimum fracture length for a gas or gas-condensate well with or without non-Darcy effects in the fracture. It is shown that the optimum fracture length depends mainly on fracture conductivity, formation permeability, size of the condensate bank around the fracture, proppant volume per unit payzone thickness, and reservoir thickness. As the fracture length is increased at a fixed volume of proppant per unit thickness, the well productivity was found to go through a maximum at a particular fracture length. The analytical results are compared with results obtained from fine-grid numerical simulations using a compositional simulator, which are run for sufficiently long periods of time so that pseudo-steady state is reached. The numerical simulation results agree well with the analytical results. The analytical expressions presented can, therefore, be used as a simple method to obtain optimum fracture lengths for gas and gas condensate wells for a wide range of conditions.