A Comparative Study Of Succinoglycan Gravel Pack Gel Properties To Those Of HEC

Abstract

SPE Members Abstract This paper contrasts the many different characteristics of hydroxyethyl cellulose polymer gels (HEC) with those of succinoglycan (SGC), a polysaccharide biopolymer. The properties included in this study are those related to gravel packing. All data and opinions are based on a comparison of HEC gels that had been properly hydrated, sheared, and filtered against SGC gels that were not sheared but were also filtered through 3.2-micron rated paper. This paper does not dwell on previously published shortcomings of HEC polymer, but by directly comparing HEC to SGC, it reveals unique new advantages that could improve the quality of gravel packs. Introduction Historically, HEC is the most used polymer for preparing gravel-pack carrier fluids, mostly because it was the best polymer available and the easiest to use. Even though other gelling agents are now available, many operators still consider HEC the best choice for gravel packing, probably because of past familiarity. However, during the past five years, research has revealed some problems with the HEC polymer that have led to changes in its preparation procedures, such as the use of exact shearing techniques and filtration to help eliminate micro-fisheyes present because of incomplete hydration. As a result, most companies now have quality control (QC) standards for HEC gels that must be met before the gels are used. Meeting these QC standards has complicated the use of HEC to a point that it is being challenged as the "polymer of choice." Dispersion and Hydration A major difference between HEC and SGC is the form in which the polymers are supplied. Instead of being in powder form as HEC, SGC is a viscous, paste-like liquid. The bulk of the liquid is water, as expected, with the amount of active polymer being about 8% by weight. The water in the SGC is essentially its fermentation broth. The polymer has never been heated for the purpose of drying it to form a powder. The SGC polymer is fully hydrated when it reaches the user. Mixing is simply a dilution process. P. 167^