Simulation of Gel Filter-Cake Formation,Gel Cleanup, and Post-Fracture Well Performance in Hydraulically Fractured Gas Wells

摘要

Polymer and gel damage is a major issue in the cleanup of hydraulically fractured gas wells. This paper addresses the issue by using a gas/water flow model that simulates fracture propagation with gel filter cake-formation as mechanical trapping of polymer molecules on the fracture face and filtrate transport into the adjacent matrix. The model accounts for polymer as a chemical component. This approach is different than treating polymer as a highly viscous gel phase, which is the common method in most literature. In this model, the gel filter-cake thickness is calculated on the basis of experimental data. For leakoff, the model allows only the sheared polymer molecules, which are the major cause of formation permeability reduction, to cross the fracture face into the formation and adsorb on the matrix. Other features of the model include water blockage, non-Newtonian flow, non-Darcy flow, and proppant and reservoir compaction.