GASBUGGY: Preshot Summary Report
Abstract
As part of the Gasbuggy preshot work, two holes, GB-1 and GB-2, were drilled and completed naturally approximately 190 and 300 feet, respectively, from the explosive emplacement hole, GB-E. The Pictured Cliffs sandstone, extending from 3916 to 4202 ft below the surface, has the following average properties: bulk density, 2.47 g/cm3; compressional velocity, 13,500 ft/sec; porosity, 10%; and water saturation, 58% (4 to 5% water content by weight). The total gas in place is calculated to be 5.8 billion cubic feet (bcf) per 160 acres. When zones having water saturations of 60% or more are eliminated, a net volume of 4.7 bcf is obtained. While core permeabilities average 0.16 md, indicated in-situ permeabilities from buildup tests are be tween 0.01 and 0.02 md. In GB-1, about 50% of the gas came from a single fracture between 4000 and 4020 ft deep, and most of the remainder came from bedding planes in the Fruitland zone, between 3800 and 3882 ft. In GB-2, most of the gas came from a fracture near the top of the Pictured Cliffs. In view of the complex flow pattern, values of reservoir characteristics derived from flow tests must be considered apparent only. We expect the 26-kt nuclear explosion at the base of the Pictured Cliffs to create a chimney between 330 and 400 ft high with a radius of 78 ft. Fracturing should extend radially about 400 ft. No flooding of the chimney with water is expected. The chimney gas is expected to contain about 200 micro C of tritium and 2 micro C of Kr85 per cubic foot of gas at normal temperatures and pressures. Rapid flaring of three chimney volumes might reduce these concentrations by a factor of ten.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1967
- Accession Number
- ADA382461
Entities
People
- Fred Holzer
Organizations
- University of California