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IDENTIFYING HYDRAULICALLY CONDUCTIVE FRACTURES WITH A SLOW-VELOCITY BOREHOLE FLOWMETER.

January 1, 1986

The U. S. Geological Survey used a recently developed heat-pulse flowmeter to measure very slow borehole axial water velocities in granitic rock at a site near Lac du Bonnet, Manitoba, Canada. The flowmeter was used with other geophysical measurements to locate and identify hydraulically conducting fractures contributing to the very slow vertical water flow in the two boreholes selected for study. The heat-pulse flowmeter has a flow-measuring range in water of 0. 06-6m/min, and can resolve velocity differences as slow as 0. 01 m/min. This is an order of magnitude slower than the stall speed of spinner flowmeters. The flowmeter is 1. 16 m long and 44 mm in diameter. It was calibrated in columns of 76 and 152 mm diameter, to correspond to the boreholes studied. The heat-pulse flowmeter system is evaluated, and problems peculiar to the measurement of very slow axial water velocities in boreholes are discussed.

Citation Information

Publication Year 1986
Title IDENTIFYING HYDRAULICALLY CONDUCTIVE FRACTURES WITH A SLOW-VELOCITY BOREHOLE FLOWMETER.
DOI
Authors Alfred E. Hess
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Geotechnical Journal
Series Number
Index ID 70015009
Record Source USGS Publications Warehouse
USGS Organization