Eco-Friendly Degradable Mechanical Diverting Agents for Combining Multiple-Staged Vertical Wells: Case History from Wasatch Formation

Abstract

Abstract The use of mechanical diverters in the oil and gas industry has been a common practice for decades, typically deploying perf ball sealers, degradeable balls, rock salt, dissolvable flakes, and incorporating downhole equipment such as sliding sleeves or straddle-packer systems. With multiple stage operations and horizontal wells becoming the industry norm, there is a need for a more permanent and reliable technology that is easily deployable and will seal previously stimulated perforations and zones from untreated perforations. This paper describes case histories from horizontal Marcellus Shale wells treated with degradable diversion materials applicable at a broad bottom-hole temperature range, maintains integrity under treating pressures and remains in place for the entire duration of well completion operations. There are a number of scenarios for which biodegradable materials are applicable: zonal isolation for horizontal wells with multiple perforation clusters, vertical wells treated through tubing where bridge plugs cannot be used, sealing off perforations for re-stimulation treatments as opposed to squeezing the perfs, and sealing off perforations after treating through coiled-tubing. The results from the case study well treated in the Uintah Basin in Utah on the Wasatch formation showed compelling evidence that temporary mechanical bridging agents can effectively replace bridge plugs and maintain zonal isolation. The concentrations of the diverter system used were optimized during the treatments and achieved typical pressure increases of 200-500 psi when deployed. The information presented in this paper will show the capabilities of using this material and the potential applications for multiple stage stimulation treatments, allowing for optimal zonal coverage and increased operational efficiency. The pressure responses from the treatments show the ability of the materials to seal the perforation clusters taking the majority of fluid and allow for diversion to understimulated perforation clusters. The production results from this candidate well additionally showed production rates higher than neighboring wells and wells typical for that area.