Novel water shut off method based on temporary plugging agent and gel composition

Abstract

This article presents the laboratory development of a novel rigless, self-selective water shut-off technique. The technique involves the design and pumping of three different fluids through fractured core plugs in a specific sequence. The first fluid serves to temporarily block porous medium while moving freely through fractures. The second fluid is a cross-linking polymer gelant, which is injected immediately after the first fluid at a pressure below the fracture pressure of the formation to block fractures. An enzyme-based chemical breaker solution, serving as the third fluid, is evaluated for removing the filter-forming materials. The treatment and flow studies are conducted using a high-pressure, high-temperature core flow setup. In conclusion, the developed water control technology presented in this study offers a low-cost solution for fractured and high-anomaly wells. The technology is particularly effective when there is a significant permeability contrast between the oil-bearing matrix and water-conductive fractures. The results demonstrate a successful blockage of fracture, with minimal contamination of porous medium. The study also highlights important factors to consider for the field application of this technology. It is recommended to conduct customized laboratory investigations under simulated reservoir conditions prior to implementing the technology in the field. This will help optimize the treatment design and ensure its effectiveness in real-world applications. Keywords: water shut-off; temporary blocking agent; gel composition; coreflood; permeability contrast.