Improved Injectability of Biopolymer Solutions
Authors: Lipton Daniel 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the 49th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Texas, Oct. 6–9, 1974. 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 paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. 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 discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
Injectability of biopolymer produced by the organism Xanthomonas produced by the organism Xanthomonas campestris can be significantly enhanced by the use of proper mixing techniques, adequate surface preservation from microbial attack, preservation from microbial attack, and the use of clean bacterial-free injection systems and source waters. An evaluation of filtration and clarification methods and costs has shown that large reduction in the number or size of cellular material can be obtained at minimal costs.

Introduction
Solutions of the microbial produced biopolysaccharide Xanflood have been studied in several field and laboratory situations to test their effectiveness as mobility control agents. It has been demonstrated that once in the reservoir Xanflood provides excellent mobility control providing certain surface treatment requirements are met. In both field and laboratory studies where the surface treatment of the Xanflood solution has been inadequate, wellbore impairment and reduced injectivity have raised questions concerning the suitability of the biopolymer for use as a mobility control agent. Examining the method of fermentation of the biopolysaccharide and microbial studies have shown the presence of bacterial cells included presence of bacterial cells included with the biopolymer during the manufacturing process. Microscopic measurement of these cells has shown dimensions of 0.3 to 0.5 micron on diameter by 0.7 to 2.0 micron length. Coulter data reported by Yost and Stokke apparently confirm these dimensions. Patton has postulated the existence of undissolved biopolymer clumps or aggregates in solution. Laboratory experiments have also shown that cellular material included with the biopolymer can provide a nutrient source for microbial growth in solutions of Xanflood which must be controlled to prevent wellbore impairment and in extreme cases degradation of the biopolymer.
The existence of microgels in biopolymer solutions and the cross-linking phenomenon with di and trivalent ions and certain complexes of boron have been seen which have a definite effect on the ultimate injectability of the polysaccharide biopolymer.