Spalling and the development of a hydraulic-fracturing strategy for coal. Semiannual report, February-July 1988

Technical Report · Tue Nov 01 00:00:00 EST 1988

OSTI ID:6230404

Bell, G J; Jones, A H; Morales, R H

Coal blocks previously recovered from a mine near Marion Center, Pennsylvania were hydraulically fractured under controlled laboratory conditions. Six tests were completed during the period, including three at low stress and three at high stress conditions. The laboratory-scale fracture treatments behaved similar to full-scale field treatments with regard to net treatment pressures and shut-in pressure profiles. Low-stress conditions, where the coal was predicted to be mechanically stable, resulted in low net pressures (less than 100 psi) and shut-in pressures quickly declined towards the closure stress. On the other hand, high stress conditions, where the coal was predicted to mechanically fail and spall at the wellbore and near the advancing fracture tip, resulted in very high net treatment pressures ( > 500 psi) and shut-in pressures remained well above the closure pressure and showed little decline.

• Research Organization: Terra Tek, Inc., Salt Lake City, UT (USA)
• OSTI ID: 6230404
• Report Number(s): PB-89-159966/XAB; TR-89-31
• Resource Relation: Other Information: See also PB--88-181946
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
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PROGRESS REPORT
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STRESSES
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012030* - Coal
Lignite
& Peat- Underground Mining- (1987-)