Application of a dynamic exploration program in conjunction with increased prices and improved production technology can result in the recovery of production technology can result in the recovery of significant commercial quantities of the natural gas considered to be entrapped in the fractured Devonian Shales in the northern Appalachian basin.
In February, 1979, under Department of Energy Contract Number DE-AC-21-79MC10389, Tetra Tech, Inc. began work on a Morgantown Energy Technology (METC) program designed to test the natural gas productivity program designed to test the natural gas productivity of dually completed wells in the Devonian Shale and Clinton Sandstone in the northern Appalachian Basin.
To insure success of the concept, an exploration program was initiated in August, 1979, under program was initiated in August, 1979, under Modification A002, to identify prospective trends and prospects for dual completion in the Devonian and other prospects for dual completion in the Devonian and other stratigraphic zones. This work is now culminating in the drilling and testing phase to substantiate the results of the exploratory work.
A single well producing from more than a single reservoir is a multiple completion technique for handling flowing production and maximizing daily output. Factors to be considered when implementing multiple completions are:
higher producing rate,
faster payout, and
multi-reservoir control requirements.
With the exception of the commingling of production from several zones in certain localized areas, production from several zones in certain localized areas, multiple zone well completions are not used in the Appalachian basin. Of the numerous possible multiple completion configurations, the Single String-Single Packer is a simple low-cost dual completion technique Packer is a simple low-cost dual completion technique having the most practicality for use in the Appalachian region. An excellent opportunity to utilize this method is afforded in wells that are drilled to objectives overlying and underlying the Devonian Shale sequence.
Operators and industrial users that are willing to include dual completions in their drilling programs will not only realize the cost effectiveness of dual completions in the Devonian Shale and another reservoir, but provide an effective low-cost means of exploiting the Devonian Shale and other reservoirs.
Pricing requirements governing tight sands and unconventional reservoirs under the Natural Gas Policy Act, may necessitate the segregation of producing intervals.
Since both have a triangular distribution (Fig.1), low-quality gas resources are similar to low-grade mineral deposits. The quantity of gas entrapped increases as the reservoir quality deteriorates. As the price for gas increases aid extraction technology improves, exploration efforts will move towards developing the lower grade reservoirs.
Geologic and engineering evidence indicates that an enormous volume of natural gas is entrapped in the matrix and in fracture systems of the low-porosity Devonian shales in the eastern United States. By using current technology, 10 to 520 Tcf of the total gas-in-place (277–2023 Tcf) is considered to be economically recoverable to meet the projected demand. It is believed that significant undiscovered commercial accumulations of gas in the Devonian shales can be located and produced, in the shortest possible time, through the application of an intensive and thorough exploration program and by use of improved production technology.
In February 1979, under Department of Energy (DOE) Contract No. DE-AC21-79MC10389, Tetra Tech, Inc., began work on a Morgantown Energy Technology Center (METC) program designed to assess the technical and economic feasibility of stimulating and producing gas simultaneously from a reservoir in the Devonian Shale sequence and another stratigraphic zone.