Controlled Solubility Phosphates - New Application Techniques Simplify Prevention In Waterfloods And Producing Wells
Authors: Sloat Ben 
Published: December 2007

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Principles which govern the selection of a particular phosphate formulation for use in each of four broad application categories are presented. The recently developed C.S.P.'s are singled out for consideration in handling the important problems of scale in waterflood producing wells and cementation of filter media in waterflood injection plants.

A new C.S.P. application technique for scale prevention known as "well packing" is described. Case Histories which illustrate the advantages as well as the practical limitations of the process are given along with a suggested method for initially sizing treatments.

A simple, inexpensive and accurate procedure for monitoring the effectiveness of "well packing" and related phosphate treatment of producing wells is shown with the standard graphical method of reporting the data.

Filter packing to prevent media fouling and cementation is a completely new approach to a problem as old as water flooding. Filter Pack Treatment considerations are discussed and a guide to the actual sizing of jobs is presented.

Introduction

Molecularly dehydrated phosphate is the workhorse of modern oilfield water treatment. Pure glassy phosphate or formulations based on glassy phosphate are used to:

Prevent deposition of calcium carbonate, calcium sulfate and barium, sulfate [Ref. 3]. Stabilize dissolved iron and manganese [Ref. 8]. Control oxygen corrosion [Ref. 4]. Clean up supply wells, injection wells and surface equipment. [Ref.9]

With four broad application categories and dozens of proprietary phosphate products from which to choose, it is not at all surprising to find a heavy degree of confusion — and even frustration — in the ranks of petroleum engineers and production men. In the past very little, if any, attempt has been made by major oilfield chemical marketers to clear up the bewilderment usually associated with the purchase of a phosphate compound for treatment of an oilfield water. Here are three important considerations:

Phosphate should always be purchased in the form of a "dry solid".