The Development and Evaluation of an Environmentally Friendly Drilling Flocculant

Solids in a drilling fluid greatly affect its properties and are generally kept to an appropriate level by chemical flocculation and solids control equipment, A high performance environmentally friendly drilling flocculant, which is a cationic gelatin, has recently been developed for solids removal from drilling fluids. In laboratory experiment, HNMR and electric potential measurement were used to chemically characterize the gelatin samples synthesized; turbidity experiment, particle size analyzation and electric potential measurement were used to evaluate and analyze the working mechanisms of the final product of the cationic gelatin. It was found that the cationic gelatin has good flocculation effect on kaolinite particles; 20 mg/L of cationic gelatin in a kaolinite suspension decreased its percent residual turbidity to 4.0%. The cationic gelatin is able to effectively encapsulate and bridge clay particles, remarkably increasing the sizes of kaolinite particles. The cationic gelatin is also able to remarkably increase the sizes of solid particles in a drilling fluid, and can reduce the solids content of the drilling fluid from 22.5% to 12.6% when used in conjunction with solids control equipment. The flocculating performance of the cationic gelatin developed is better than the commonly used flocculants such as hydrolyzed polyacrylamide.