Abstract:
Chemical Water shut-off appears as an effective tool for blocking unwanted water zones; the techniques require chemical placement or injection into the reservoir to treat fluids in the target zone. Many types of chemicals were presented in the market includes Inorganic gels, Polymer gels, Biopolymers and Viscous flooding. Polymer is a chain of molecules made up of many repeating units. It has Linear, Branched, or Cross- linked Structure. The synthetic polymers cannot completely meet the requirements under high temperature or high salinity they also non-environmentally friendly and have poor shear resistance.
Although Natural Polymers are abundant in Sudan; recently, no detailed study has been performed for our indigenous natural polymers for potential use in chemical shut off. Through this study, a new discovered natural polymer named as STLK – 4 have been primarily evaluated for potential use in chemical shut off.
Moisture content, critical concentration and insoluble materials were first evaluated according to SY/T 6376 (2008). Aqueous solution was then evaluated under different temperature and shear rate for fluid concentration of 0.5, 1.0, 1.5, and 2.0% using Cannon and Fan 6 speed combined with KINEXUS rheometers.
Moisture content was found to be 11.56%, which is acceptable, according to SY/T 6376 (2008). While the insoluble materials was found to be 19% for fluid concentration of 2%, and was classified in the third category of the category of SY/T 5764. Critical concentration was estimated as 1%.
Aqueous solution presented a Non-Newtonian pseudo plastic (shear thinning) behavior; the viscosity decreased with shearing with power law relationship. The fluid has slight thermal degradation, and a very low biodegradation was observed in low concentrations; while increment was achieved in viscosity after 24 hr, which indicates fully polymer hydration, occur with time.
