Application of Okra Mucilage for the Prevention of Shale Swelling

Abstract

Abstract Maintain wellbore stability is a very critical aspect of the drilling operation. The unstable wellbore provides severe loss to the drilling operators in terms of time and money. One of the significant reasons for unstable wellbore occurs due to the expansion of shale formation. Several solutions are utilized to tackle the expansion of shales, such as salts, PHPA, silicates, and oil-based drilling fluids. There are limitations associated with these solutions, such as thermal instability, limited supply, unfriendly to the environment and marine life, etc. In this study, Okra mucilage has been introduced as a shale swelling inhibitor in drilling fluids. Okra is widely used in the medical and food industries as a viscosifier as it is abundantly available in tropical and subtropical regions. Okra powder has been used as a fluid loss control additive in the literature. The application of the Okra solution as a shale swelling inhibitor in drilling fluids was not investigated in the past. In this study, Okra mucilage was extracted from the Okra plant and used as shale swelling inhibitor. Three different concentrations (5, 10 & 20) vol% of Okra mucilage mixed solutions were used for linear swell test. The test was performed using a linear swell tester at atmospheric conditions for 24 hours on bentonite wafers. Further zeta potential, particles size and capillary suction timer test (CST) were conducted. The experimental study revealed that Okra mucilage reduced the swelling of bentonite. For instance, 10 and 20% of Okra mucilage solutions reduced the swelling by 36.8% and 50.5%, respectively. The Okra mucilage decreased the zeta potential of clay and increased its particle size. CST time decreased initial at low concentration and increased with concentration. Overall, experimental investigations suggested that Okra mucilage could be an alternate green shale inhibitor in drilling fluids without compromising other drilling fluids' properties.