Assessment of Transmissivity of the Weathered Upper Part of Horizontally Layered Bedrock

Abstract

The results of flowmeter tests of wells in the upper part of a layered rock massif indicate a model of the permeability medium in the form of separate horizontal thin fracture zones, separated by layers with a thickness of several meters. Pumping was studied with a model in cylindrical coordinates for two thin aquifers. The upper one works with a constant pressure in pumping a well, determined by the position of the zone, and a decreasing rate, and the lower, with an increasing rate, is additional to the pump rate. The filter intervals of the central and the only observation well are the same. Processing of the pumping results with the commonly used Jacob method showed the main features: strong differences in transmissivity in different variants of well locations, unrealistically large values of the storage coefficient, and an ultrasmall calculated radius of the pumping well.