Practical Experience with Water Control in Gas Wells by Polymer Treatments

Abstract

The paper deals with the appraisal and applicaiion detayed. lnjectivity and produtivity of the welis of waxer control technologies for gas wells and were improved by a rcduction in friction Ioss m gas storage welis. A laboratory evaluation of the vicrnity of the well bore, presumably due to different polymer products for a variety of polymer adsorption. reservoir conditions -temperaxure, salinity of reseoir brine, rock peeability was performed. For the numencal characterization of polymers, the performance factor, which is the residual resistance factor for water divided by the resistance factor of the polymer solution, was used to select the best suited products for 4 caiididate welis. The investigations were performed by 3 mdependent laboratones DBI-GUT m Freiberg, IFP m Paris and ITE in Clausthal. Twa examples of field application are presented:The high temperature gas well Salzwedel 85, which suffered from secondary water migration through a depletcd gas layer and the gas storage well Buchholz P 17 with moderate depth and temperaxure, in which water production penodicily occurred at the end of theproduction period. Successful treatments could be performed in both cases and the results have shown that secondary water influx could be stopped and water break-through in a storage welt couid be 48 IiictionWater influx m production wells is a generaf problem whîch dominates the cost side of production. Exccssive water production can resuk in reduced well productivity, extra corrosion sand production and increased envîronmental protection costs. On the other side, water injection and aquifer expansion are vital mechanisms for oil production and pressure maintin2nce in reservoiis. Measurcs to separate the formation water from oil and gas m the reservoir have been tried for many years at dîfl'erent reservoir conditions, with different methods and products, J. Morgan /1/ from BP Exptoration concludes from an analysis of various interventions m existing wells to slow the passage of water, that ,,there is no cure -alt proccss at present and what is successful in one field, may be inappropriaxe elsewhere". Y. Guerrini, N. Kohler and A. Zaitoun /2/ classify the water control methods, depending on the structure of the reservoir rock into -permanent barner methods -selective barner methods lf waler and hydrocarbon zones are clearly separated, processes using permanent barners which can be ptaced m the water bearing zones, generaily give good results. They can be formed by injection of cements, resins or silicate gels. However, when oil, gas and water are fiowing simultaneously, potymer solutions and/or getants are injected which can biock the water phase, but remain permeabte to oil and gas, Depending on the type of reservoir rock, reservoir temperature and salinity of the reservoir brine, different potymer substances can be used for biocking the water. For Iow salinity conditions and moderate telnperatures, polyacrylaniides have been often used together with crosslinking agents to fonn gels whereas for higher sairn...

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Relative Permeability Modifier Treatments on Gulf of Mexico Frac-packed and Gravel-packed Oil and Gas Wells

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