Removal of Water Soluble Organics from Produced Brine without Formation of Scale

摘要

Water Soluble Organics (WSO) are included in themeasurement of Oil and Grease (O&G), a conventionalpollutant controlled by the Clean Water Act. WSO partition tothe produced brine at the production pH but to the extractionsolvent used to measure the O&G at the test pH of < 2. Thepredominant chemical species comprising WSO in Gulf ofMexico crude oil brines are medium chain carboxylic acids.Chemicals can be added to desolubilize these species inconjunction with treatments to remove the resultant emulsion.For a variety of reasons, the most reliable and cost effectivedesolubilization agents have proven to be the non-volatile,multi-protic oxy acids (e.g. HxSOx and HxPOx). However, inthe presence of divalent cations in the brine, these forminsoluble scale deposits. Moreover, in the presence of WSO inmixed production, this scale becomes oil wet anduninhibitable. A new treatment comprising a new class ofdesolubilizer in conjunction with certain polymers has nowbeen shown to be equally reliable and cost effective withoutthe formation of scale even at extreme concentrations ofdivalent cations. The chemistry is explained and case historieschronicled to illustrate its effectiveness in the field.