Abatement of Water Production from Upper Permian Gas Wells in Saudi Arabia Using a New Polymer Treatment

Abstract

Abstract Excessive water production adversely affects the economics of gas wells and often leads to their premature shut-in. Production of high salinity water represents a major corrosion concern for casing, tubing, flow lines, and production facilities. Water production from gas wells can be significantly reduced by using water-soluble polymers or by blocking the flow of water using a suitable gel system. A non-associate gas is being produced from the Upper Permian gas wells (Khuff carbonate gas reservoirs). Some of these wells produce large amount of very saline water (217 g/l). A chemical treatment is needed to reduce the amount of water produced. An experimental study was conducted to screen various polymer solutions and gelling systems to treat gas-producing wells in the Khuff gas reservoirs. Experimental work included compatibility of two-water soluble polymers with Khuff reservoir brine, adsorption of these polymers on reservoir rocks, rheology of polymer solutions, injectivity and flow of these polymers into core plugs obtained from Khuff formation, at reservoir conditions. The two polymers examined were compatible with Khuff reservoir brine under reservoir conditions. The amount of polymer adsorbed on reservoir rocks increased at higher polymer concentrations. Core flood tests showed that an organically cross-linked polyacrylamide-based polymer demonstrated the best performance for treating high permeability streaks where the gel treatment reduced the effective permeability to brine without affecting that to gas. Rheological measurements indicated that this gelling system could be placed into the target zone by bull heading or by using coiled tubing.