Project to test for shale gas in Ohio. Final report

Technical Report · Wed Apr 01 04:00:00 EST 1981

OSTI ID:6289594

The search for viable shale gas is the search for fractures in the shale. One possible method to find deep zones of natural fracture is the measurement of the speed of sound in the shale. This speed is expected to be lowered by the presence of fractures, particularly if the fractures contain gas. The seismic reflection method, which times the echoes from deep rock layers, can be used to measure the speed of sound (the seismic velocity) in the shale. Accordingly the present project was undertaken to make such measurements along a 125-mile line crossing SE Ohio, to search for local lowering of this speed, and to drill and test 1 to 3 shale-gas wells on such local lows. The results of the seismic velocity analysis are summarized. Several velocity lows are apparent, and two of these were proposed for test. A well was drilled on one of these anomalies in Elk Township, Noble County. Gas was obtained from two naturally-fractured zones in the Chagrin shale. The well was stimulated and tested at three separate levels: the Rhinestreet shale, the Huron shale, and the Chagrin. Initial production is of the order of 30 Mcf/d from the Rhinestreet, 35 Mcf/d from the Huron, and 110 Mcf/d from the Chagrin. Economic analyses suggest that the Rhinestreet and Huron are not in themselves commercial; the Chagrin is marginal at a gas price of $2/Mcf but commercially attractive at $5/Mcf. Practical problems remain in the preparation of seismic velocity analyses, and enigmas remain in interpreting the test well. However, velocity analysis seems to have a place among the techniques for locating shale-gas wells.

• Research Organization: Donohue, Anstey and Morrill, Boston, MA (USA)
• DOE Contract Number: AC21-79MC08339
• OSTI ID: 6289594
• Report Number(s): DOE/MC/08339-1348; ON: DE83006907
• Country of Publication: United States
• Language: English

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