The Development and Application of an Environmentally Friendly Encapsulator EBA-20

Abstract

At present, the encapsulators of drilling fluids used in domestic oilfield are mainly organic polymer compounds. These encapsulators show good performance in their own drilling fluid systems. However, they also demonstrate some defects, such as narrow range of applicability, unsatisfactory temperature resistance and salt tolerance, incapability to meet the requirement of corresponding national standards for environmental protection, and so on. Using biopolymer as the main monomer and mixing with nonionic, anion, and cationic monomer, the authors develop an environmental friendly encapsulator EBA-20 with temperature resistance and salt tolerance by aqueous solution polymerization method. Laboratory test and field application show that the synthetic encapsulator EBA-20 can improve the viscosity and yield value of drilling fluid and reduce the fluid loss of drilling fluid. Meanwhile, its temperature resistance and salt tolerance are also better. The contents of main heavy metals, such as chromium and mercury, are under the standard level of GB4284-84; the value of acute biotoxicity test EC50 is greater than 30,000 mg/L, which has little influence on environment; the value of biodegradability BC is 20.1, which shows that EBA-20 is biodegradable and is useful for drilling fluid system to improve its environmental protection performance. Formulation #1, which takes environmentally friendly encapsulator EBA-20 as marine drilling fluid system, meets the requirements of drilling operation and has an excellent environmental protection performance. It could reduce environmental pollution to the operating area in the marine.