Evaluation of rheological properties of the exopolysaccharide of Sphingomonas paucimobilis GS-1 for application in oil exploration

Abstract

Analysis of an exopolysaccharide of Sphingomonas paucimobilis GS-1 (EPS/GS-1) with respect to its rheological properties, cross-linking ability with chrome alum and performance test at 75 ± 5°C revealed its strong suspending ability, shear thinning property, and thixotrophic nature which are required to impart desirable rheology to drilling mud. The organism fulfilled all the specified requirements and its properties were superior to those of currentlyused XC polymer (a xanthan product) for oil drilling applications. However, EPS/GS-1 was unstable in the presence of bentonite at 100 ± 5°C during performance tests, in contrast to XC polymer.