| Abstract |
AltaRock Energy, Inc. (ARE) has collaborated with the University of Utah (UU), with a Phase I grant in 2018 from the U.S. Department of Energy’s Small Business Innovative Research (SBIR) program, to develop a unique method to permanently seal unwanted fractures in wells with elevated temperatures. This technology is covered by three issued patents owned by UU (U.S. Patent Numbers 8,091,639; 8,353,345; 8,522,872) and exclusively licensed to ARE for monetization. The Phase I work included laboratory work at the Energy and Geoscience Institute at UU to determine optimum placement conditions, research to determine the best emplacement methods, drafting of a robust field procedure and the development of a commercialization plan. The method emplaces a diversion agent into a specific region of a well to seal unwanted fractures with calcium carbonate. The calcium carbonate formation is a function of both temperature and pH, thus allowing control of where the agent is placed in the well (e.g., specific fracture locations). The technology is based upon the in-situ decomposition of urea in the presence of CaCl2 to precipitate CaCO3 (Rose et al., 2008). A series of experiments conducted at the University of Utah showed that the optimum reaction conditions to block potential fractures occur when the reaction is held at 150 °C using a buffered solution at a pH 9. Methods for field deployment include coil tubing, rig, pumping from surface and wireline bailers. Each one of these options is explored from the perspectives of wellbore risk, job success and cost. A general, but robust field procedure was written to provide AltaRock with the detailed steps to conduct these jobs in any field. Finally, a commercialization plan was drafted. The mineral grouting technology is ideally suited for geothermal industry and has the potential to be used in certain high temperature applications in the oil industry like steam floods or SAGD. Presently, unwanted fractures are sealed either mechanically with bridge plugs, packers, scab liners or by cementing. The mineral grouting solution is expected to be less expensive and lower risk than technologies currently used to seal problematic fractures in a wellbore. This paper will summarize the work and conclusions of the Phase I SBIR grant work and explain its relevance to the geothermal and petroleum industries from a commercialization perspective. |