High viscosity biopolymer gels such as Welan and Xanthan gums are routinely used in Coiled Tubing (CT) operations. These operations range from common fill cleanouts to removing excess cement during CT squeeze jobs and for other applications such as CT underreaming of cement or other tenacious fills. These gels were chosen because of their highly desirable rheology characteristics and the their extremely low biological risks1 . However, biopolymer gels have proven to be very difficult to break and process for solids removal and under some circumstances, can wreak havoc in oil processing operations.
This paper documents a test program that culminated in the identification of a process that effectively breaks these gels allowing higher solid removal efficiency and produces a liquid phase that has been shown to be compatible with oil processing.
The processing technique described in the paper has been field tested to quickly and effectively break back the difficult to clean, high viscosity biopolymers. Prior testing identified only a few chemicals such as ferric chloride and potassium permanganate that would rapidly flocculate high pH biopolymers. Unlike the aforementioned chemicals, the organic, cationic poly-electrolyte used in the process posses an extremely low health hazard and is "of low toxicity." Thus the process described is the paper is aligned with the goals of operations that pose minimal impact to the workplace and environment.