Preliminary Observations of Postshot Geologic Effects of Gasbuggy Nuclear Stimulation Experiment, Northeastern San Juan Basin, New Mexico

William B. Martin

Project Gasbuggy, an experiment dealing with the nuclear stimulation of low-permeability reservoir strata, was the first experiment conducted jointly by industry and government.

Postshot geologic investigations and studies suggest the alteration of physical rock properties at a greater radial distance from the shot point than was anticipated.

Investigations of pre- and postshot conditions also suggest three, rather than two, zones of rock deformation: (1) Chimney zone, radius of 80 ft, or approximately 0.5-acre drillsite equivalent, filled with rubble, (2) Shatter or crushed zone, radius of 500+ ft, or approximately a 20-acre drillsite equivalent, in which extreme changes in the reservoir conditions and the physical properties of the rock have occurred, and (3) Fracture zone, radius of 650-700 ft, or approximately a 40-acre drillsite. There is some evidence to suggest that the fracture radius extends to 1,000 ft (approximately an 80-acre drillsite equivalent) and possibly farther. The fracture zone should consist of a nearly infinite number of radial fracture systems distributed around the point of detonation.

Additional postshot investigations are continuing and as data are obtained, more precise conclusions can be made regarding the radial extent of improvement in reservoir characteristics resulting from nuclear stimulation.

AAPG Search and Discovery Article #91051©2012 AAPG Rocky Mountain Section Meeting, Albuquerque, New Mexico, 23-26 February 1969