Exploration strategies based on a coalbed methane producibility model

Conference · Mon Jan 01 04:00:00 EST 1996 · AAPG Bulletin

OSTI ID:6567075

Scott, A R; Kaiser, W R; Hamilton, D S; Tyler, R; Finley, R J ^[1]

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1. Univ. of Texas, Austin, TX (United States)

Knowing geologic and hydrologic characteristics of a basin does not necessarily lead to a determination of its coalbed methane producibility because it is the synergy among key hydrogeologic controls that governs producibility. Detailed studies performed in the San Juan, Piceance, and Sand Wash Basins determined that the key hydrogeologic factors affecting producibility include depositional setting and coal distribution, tectonic and structural setting, coal rank and gas generation, hydrodynamics, permeability, and gas content. The conceptual model based on these factors provides a rationale for exploration and development strategies for unexplored areas or in basins having established or limited production. Exceptionally high productivity requires good permeability; thick, laterally continuous high-rank and high-gas-content coals; dynamic flow of ground water through those coals; generation of secondary biogenic gases; and migration and conventional trapping of thermogenic and biogenic gases. Higher coalbed methane producibility commonly occurs in areas of upward flow associated with permeability barriers (no-flow boundaries). Fluid migration across a large gathering area orthogonal to permeability barriers and/or in situ generation of secondary biogenic gases concentrate the coal gas, resulting in higher gas contents. Low coalbed methane production is typically associated with very low permeability systems; the absence of conventional or hydrodynamic traps; and thin, low-rank coals below the threshold of thermogenic gas generation. Production from relatively low-gas-content coals in highly permeable recharge areas may result in excessive water and limited coalbed methane production. Thus, high permeability can be as detrimental to coalbed methane producibility as is low permeability.

• OSTI ID: 6567075
• Report Number(s): CONF-960527--
• Conference Information: Journal Name: AAPG Bulletin Journal Volume: 5
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
011000 -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
ALKANES
COAL DEPOSITS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
HYDROCARBONS
METHANE
MINERAL RESOURCES
NATURAL GAS
NATURAL GAS DEPOSITS
ORGANIC COMPOUNDS
PRODUCTION
RESERVES
RESOURCE DEVELOPMENT
RESOURCES
SEDIMENTARY BASINS