Softening of Oilfield Produced Water by Ion Exchange for Alkaline Flooding and Steamflooding

Abstract

ABSTRACT Oilfield "produced" waters usually contain high hardness, and high dissolved solids along with some alkalinity. The problem of disposing of these waters and the need for huge volumes of water for alkaline water flooding and steam generation for steam floods, necessitate the softening and reinjection of softened produced water. Water for alkaline and steam flooding needs to be softened to almost zero hardness to prevent plugging during injection and to prevent scaling on boiler tubes. Softening of high TDS and high hardness waters requires a very selective resin with high operating capacity such as a weak carboxylic acid-type ion exchange resin. Conventional softening with strong acid resins would not work under these conditions. This paper discusses the different processes in softening oilfield produced water. Data obtained in softening varieties of produced waters from different oilfields in California will be presented. Performance characteristics of weak cation exchange resins and their chemical regenerant requirements will also be discussed.