Comparative evaluation of vertical and horizontal drainage wells for the degasification of coal seams

Journal Article · Sun May 01 00:00:00 EDT 1988 · SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States)

DOI:https://doi.org/10.2118/13091-PA· OSTI ID:6685061

King, G R; Ertekin, T

A two-phase, single-well, numerical simulator capable of modeling the performance of either vertical or horizontal wells (drilled from a shaft bottom) has been developed. For vertical wells, the model allows for the prediction of postfracture performance. The hydraulically induced fractures can be specified as either infinite conductivity or finite (constant) conductivity, so that conventional, as well as massive, treatments can be modeled. Although the simulator allows for multiple fracture wings, only the classic, two-wing, hydraulic fracture is considered in this paper. For coal seams, the formation to be modeled is a dual-porosity reservoir. The natural fracture network of the coal seam (the butt and face cleat) has been assigned an effective porosity and permeability. A time-dependent, quasisteady-state sorption term has been included to describe the phenomenon of gas desorbing from the formation matrix and diffusing into the fracture network. The model was used to sift through the many parameters associated with the two production schemes to determine those that affect production most significantly. Where possible, these parameters, along with their effects, are put into dimensionless form. Type curves for estimating recovery were generated from these dimensionless groups. Finally, a comparison between the performance of vertical and horizontal boreholes was made with actual field data.

• Research Organization: Chevron Geosciences Co., Houston, TX (US)
• OSTI ID: 6685061
• Journal Information: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Vol. 3:2
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL SEAMS
DEGASSING
BOREHOLES
COAL MINING
COMPARATIVE EVALUATIONS
DIRECTIONAL DRILLING
DRAINAGE
FLOW MODELS
GEOLOGIC FRACTURES
HYDRAULIC FRACTURING
HYDRAULICS
INCLINATION
MATHEMATICAL MODELS
UNDERGROUND MINING
CAVITIES
COAL DEPOSITS
COMMINUTION
DRILLING
FLUID MECHANICS
FRACTURING
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
MECHANICS
MINERAL RESOURCES
MINING
RESOURCES
012030* - Coal
Lignite
& Peat- Underground Mining- (1987-)