Chapter 25 - Formation and completion damage problems in tight reservoirs: conventional or unconventional

Abstract

Most unconventional and some conventional reservoirs have extremely tight formations, and therefore, involve various types of complicated formation and completion damage problems. Economic production of tight and unconventional reservoirs requires the completion of multistage proppant-packed hydraulically fractured multilateral wells. Various undesirable formation damage problems can arise because of interactions of fracturing fluids with reservoir formations, clay swelling and migration, adsorption of polymers contained in fracturing fluids, buildup of filter cake of gel of fracturing fluids over the fracture face, aqueous phase trapping, and reduction of relative permeability by irreducible fracturing fluid. Proppant deformation and embedment over the hydraulic fracture surfaces in soft or unconsolidated and deformable formations can cause proppant pack porosity and conductivity loss. This chapter presents a review of some special issues of formation and completion damage problems important for tight and unconventional reservoirs which were not covered in previous chapters. Impairment of hydraulic-fracture conductivity by proppant diagenesis, embedment, and compaction in hydraulically fractured tight reservoirs, fracturing fluid-induced formation damage involving multistage hydraulically fractured horizontal wells completed in tight gas reservoirs, aqueous phase trapping damage, and prevention and mitigation of aqueous phase trapping damage are reviewed.