Properties of Chitosan-based pH-Sensitive Superabsorbent Polymer Modified Oil Well CementAuthor(s): Chunyu Wang, Yuhuan Bu and Zhonghou Shen
Poor zonal isolation due to microcracks in cement sheath is a common problem that affects oil and gas exploration and also impacts the environment. Chitosan-based superabsorbent polymer (CSAP) was synthesized and was used as a self-healing agent for sealing microcracks of cement sheath. CSAP was prepared by solution polymerization. The effect of glutaraldehyde (GA) dosage and chitosan (CS) concentration on the stability of CSAP was studied. It was determined that GA addition should be greater than 0.15% and the CS concentration should be less than 3%. The water absorbing performance of CSAP was pH sensitive and had a pH-sensitive threshold of 10. The pH sensitivity of CSAP ensured that the stability of the cement slurry was less affected, and the properties of cement slurry met the requirements of cementing construction. The CSAP modified oil well cement would guarantee the health, safety and high efficiency in the process of oil and gas production.