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

摘要

Excessive water production adversely affects the economics ofrngas wells and often leads to their premature shut-in.rnProduction of high salinity water represents a major corrosionrnconcern for casing, tubing, flow lines, and productionrnfacilities. Water production from gas wells can be significantlyrnreduced by using water-soluble polymers or by blocking thernflow of water using a suitable gel system.rnA non-associate gas is being produced from the UpperrnPermian gas wells (Khuff carbonate gas reservoirs). Some ofrnthese wells produce large amount of very saline water (217rng/l). A chemical treatment is needed to reduce the amount ofrnwater produced.rnAn experimental study was conducted to screen variousrnpolymer solutions and gelling systems to treat gas-producingrnwells in the Khuff gas reservoirs. Experimental work includedrncompatibility of two-water soluble polymers with Khuffrnreservoir brine, adsorption of these polymers on reservoirrnrocks, rheology of polymer solutions, injectivity and flow ofrnthese polymers into core plugs obtained from Khuff formation,rnat reservoir conditions.rnThe two polymers examined were compatible with Khuffrnreservoir brine under reservoir conditions. The amount ofrnpolymer adsorbed on reservoir rocks increased at higherrnpolymer concentrations. Core flood tests showed that anrnorganically cross-linked polyacrylamide-based polymerrndemonstrated the best performance for treating highrnpermeability streaks where the gel treatment reduced therneffective permeability to brine without affecting that to gas.rnRheological measurements indicated that this gelling systemrncould be placed into the target zone by bull heading or byrnusing coiled tubing.