Design and Feasibility of Creating Gas-Storage Caverns by Using Acid to Dissolve Carbonate Rock Formations

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe feasibility of creating gas-storage caverns by dissolving carbonate rock formations was examined based on process design, geologic factors, and preliminary economic analysis. The method involves drilling one or more wells, pumping acid into the formation, and then removing and treating the waste fluid. To enhance acid transport into the formation, the rock may be hydraulically fractured prior to pumping the acid.To analyze the requirements for creating storage volume, the following were examined: weight and volume of rock to be dissolved; gas storage pressure, temperature, and volume at depth; solubility of acid-rock reaction products; and acid costs. Design considerations and economic calculations indicate that the new method will be applied most advantageously to carbonate formations deeper than approximately 4000 feet, with limestone at depths between 6000 and 9000 feet preferred. In order to identify potential sites for applying the new method to creating storage volume, a large amount of data from carbonate formations was compiled for six states: Ohio,

Underground gas storage: Why and how

“…There has been a recent proposal to create caverns for gas storage in limestone formations through dissolution by acid, using solution mining techniques in a similar way to which salt caverns are created (Castle et al 2004). This process is still in the research phase and there are many factors that require further investigation, including gas tightness of the caverns, cavern stability and disposal of the large amounts of CO 2 (with attendant greenhouse gas effects) that will be generated by the dissolution of the limestone.…”

Pressure transients to characterize cavities dissolved for natural gas storage

“…New capacity is desired for storing natural gas near end-use markets, and we proposed to store the gas in cavities created in limestone (Castle et al, 2004). The basic strategy would be to inject acid in one pipe extending to the bottom of a deep boring in limestone.…”

“…The acid would first enlarge the boring, and later dissolution would expand the boring into a cavern. Dissolution products would be removed from another pipe next to the one used for injection (Castle et al, 2004). Pressure transients moving down the injection pipe would be affected by changes in the diameter of the conduits (pipes and cavern), and contrasts in density due to different solute 3 concentrations.…”

“…A new method of natural gas storage has been proposed (Castle et al, 2004), in which aqueous hydrochloric (HCl) acid is injected into a carbonate rock formation to create a storage cavern. Such a cavern could store as much as 1 billion cubic feet of natural gas (Castle et al, 2004). Natural gas storage in a solution-mined carbonate cavern has several advantages over other storage methods.…”

“…Suitable carbonate rock formations are more common than salt domes in the northeastern U.S., such as in New England and the Great Lakes region (Yang, 2004;Atteberry et al, 2005). Carbonate rock caverns require less cushion gas and are characterized by less loss than storage in porous formations, so this method is appealing (Castle et al, 2004).…”