Ammer and Sames discuss results in the Stark-Summit/Chippewa gas storage field in East Ohio. Wells with higher non-Darcy flow components responded better to re-stimulation.
Major studies completed by the U.S. Department of Energy/National Energy Technology Laboratory (NETL) have documented or demonstrated advances for improved storage deliverability and new storage facilities. These technological advances are very important for maintaining the reliability of the natural gas infrastructure since energy forecasts predict that the Nation's demand for natural gas is likely to exceed 30 Tcf per year by 2015. The anticipated growth in electricity generation demand for natural gas will require the delivery system to be re-optimized to meet larger off-peak swing loads as well as peak-day requirements that could increase from 111 Bcf per day (1997) to 152 Bcf per day by 2015.
Four new and novel fracture stimulation technologies - liquid CO2 with proppant, propellant, tip-screenout, and extreme overbalanced fracturing - were tested in eight different storage fields. In total, 29 fracture treatments were performed as part of the project. Several of these new and novel stimulation technologies provided attractive deliverability enhancement results and addressed the special concerns of gas storage operators. Three new projects were started in the fall of 1999 to investigate improved remedial treatment technologies.
Studies of the technical and economic merits of four advanced storage concepts were also completed. Three of these new or improved storage methods can provide storage in areas where conventional storage is not available or does not meet the requirements of end-users. The large-scale projects, lined rock caverns and refrigerated-mined caverns, have been shown to be superior to LNG storage when using several cycles. A feasibility study of storing gas as hydrates found that a single formation and decomposition cycle could be achieved within 24 hours in a 2.25-MMcf process. Using an advanced constitutive model developed for nuclear waste isolation in salt, the fourth study found that minimum working gas pressure in most existing salt cavern storage facilities can be lowered 10 percent without compromising cavern stability. Extrapolating these results across the salt cavern industry would result in a 17-Bcf increase in storage capacity with no changes to existing infrastructure. A fifth study, initiated in 1999, is investigating the feasibility of storing gas in basalt aquifers.
Author(s): James R. Ammer, Gary P. Sames, U.S. Department of Energy/National Energy Technology Laboratory
Paper Number: SPE 65638