Solubility and Density Limitations of Solutes for Clear High Density Fluids and Some Economic Consequences
Authors: Anderson Jerre T. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for International Symposium on Oilfield Chemistry of the Society of Petroleum Engineers of AIME, to be held in Dallas, Texas, Jan. 16–17, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

The techniques described in this paper were evolved in an effort to use paper were evolved in an effort to use handbook data of the solubility and density of pure compounds to screen compounds for possible use in high density clear completion fluids. While solutes were found that met the physical criteria developed, they were physical criteria developed, they were all too expensive to be practical in large volumes. Curves developed for use in the screening process illustrate solubility and density limitations.

Introduction

The solids in drilling muds can settle out on packers, form a filter cake on the wall of a hole, or penetrate and damage a formation. penetrate and damage a formation. Because they are solutions containing little or no suspended solids, clear completion fluids are often used downhole behind packers and during perforation or packers and during perforation or workover.

For some time aqueous solutions of such salts as sodium carbonate and the chlorides of sodium, calcium and zinc have been used singly and in combination in completion fluids. Recently mixtures of calcium chloride and calcium bromide have appeared. The maximum density attainable with such systems is about 2 gm/cc (16.7 lb/gal) which limits the bottomhole pressure that they can control. pressure that they can control. Furthermore, some of these systems are corrosive. The work reported here was part of an effort to develop a clear part of an effort to develop a clear completion fluid with a density of 2.16 gm/cc (18 lb/gal) for use in gas wells producing a high percentage of hydrogen producing a high percentage of hydrogen sulfide.

A search of solution density tables in commonly available compilations failed to reveal any desirable candidates for a high density completion fluid. It appeared that any further search could involve an extensive program of laboratory screening or an program of laboratory screening or an extensive literature search or both. The procedures reported here were evolved in an attempt to eliminate the need for the extensive literature search and to reduce the number of compounds selected for laboratory tests to a manageable level. Although evolved to solve a specific problem, these procedures are of general applicability. procedures are of general applicability.