Coalbed methane research. Annual report, FY82

Technical Report · Tue Mar 01 04:00:00 EST 1983

OSTI ID:6033558

Towse, D F; Hanson, M E; Costantino, M S; Kusubov, A; Qualheim, B J; Thorson, L D

During FY82, the Lawrence Livermore National Laboratory conducted field experiments, laboratory tests, and mathematical modeling directed toward the safe production of methane from mineable coal seams. Sampling and in-situ stress tests at three sites in the east and sampling at one mine in the west were followed by hydraulic stimulation treatments in vertical drill holes. Subsequent mining to the drill holes and underground mapping were completed at one eastern site only. At that location, the in-situ stress tests by hydraulic minifracturing have a food indication of the expected fracture response during stimulation. In particular, the minifrac records indicated a shut-in pressure that was comparable to the expected vertical stress. This raised the possibility of the hydrofracture becoming horizontal away from the wellbore. The mineback revealed both vertical and horizontal fracturing due to stimulation. Stress measurements both in coal and adjacent coal-measure rocks at two sites showed the coal stress to be markedly lower at both sites: the difference in horizontal stresses was estimated from 1.9 MPa (260 psi) in Pennsylvania, to over 8 MPa (1160 psi) in Kentucky. This indicated that the stimulation fracture should be contained in the coal if proper care were exercised during pumping. The single mineback in Pennsylvania showed fracture containment. A more complete analysis of these experiments will be possible when additional test-pressure records and mineback data are available.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6033558
• Report Number(s): UCRL-53421; ON: DE83015301
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012000* -- Coal
Lignite
& Peat-- Mining
ALKANES
CARBONACEOUS MATERIALS
COAL
COAL DEPOSITS
COAL SEAMS
COMMINUTION
DATA BASE MANAGEMENT
DEGASSING
ENERGY SOURCES
FOSSIL FUELS
FRACTURING
FUELS
GEOLOGIC DEPOSITS
HYDRAULIC FRACTURING
HYDROCARBONS
MANAGEMENT
MATERIALS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
METHANE
MINERAL RESOURCES
ORGANIC COMPOUNDS
PRESSURE MEASUREMENT
RECOVERY
RESOURCES
ROCKS
SITE SELECTION
STIMULATION
WELL LOGGING
WELL STIMULATION