Mechanical factors affecting stimulation design in Devonian gas shale

Conference · Tue Mar 01 04:00:00 EST 1983 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6419806

Gregg, W J; Mroz, T H

Oriented core samples from 23 Devonian gas shale wells in the Appalachian basin were used to determine microscopic and mesoscopic fracture patterns. The specific objectives were to note the preferred direction and nature of natural microcracks, to determine the preferred fracture propagation direction in laboratory mechanical testing, and to outline areas in the basin that are characterized by a high natural fracture density in the gas shales. This information provides a necessary background for the development of the in-situ stimulation technology which would most effectively connect natural fracture systems to a single well bore. Natural fractures were measured prior to testing. The preferred orientation of both induced and natural fractures throughout the basin was generally parallel to the trend of Paleozoic tectonic structure. The trajectory maps for in-situ stresses in the basin clearly illustrate the lack of parallelism with the mechanical fabric of the shale. However, analysis of the two patterns has been used to outline local areas in the basin where sigma/sub Hmax/ is parallel to the natural microcrack system. In these areas the natural crack array would be oriented so as to facilitate induced crack propagation. Combined with an analysis of hydrocarbon potential and the location of detachment zones related to basement deformation, these relationships offer a useful rationale for targeting areas for future unconventional gas recovery programs. In addition they provide a framework for understanding the behavior of the rock mass in response to hydrofracture stimulation in less promising areas of the basin.

• Research Organization: Michigan Tech. Univ., Houghton
• OSTI ID: 6419806
• Report Number(s): CONF-8304200-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 67:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
BOREHOLE LINKING
COMMINUTION
DEVONIAN PERIOD
ENGINEERING
FAILURES
FRACTURED RESERVOIRS
FRACTURES
FRACTURING
GEOLOGIC AGES
GEOLOGIC DEPOSITS
HYDRAULIC FRACTURING
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PALEOZOIC ERA
RESERVOIR ENGINEERING
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SHALES
STIMULATION
WELL STIMULATION