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Interpretation of Boundary Effects From Pumping Test Data
Author(s) -
Lang S. M.
Publication year - 1960
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1960.tb00499.x
Subject(s) - aquifer , aquifer test , aquifer properties , well test (oil and gas) , boundary value problem , boundary (topology) , geology , transmissibility (structural dynamics) , image (mathematics) , test data , mathematics , computer science , mathematical analysis , geotechnical engineering , petroleum engineering , groundwater , artificial intelligence , physics , groundwater recharge , programming language , vibration isolation , quantum mechanics , vibration
The hydraulic characteristics of an aquifer that define its abilities to store and transmit water are generally determined from the analysis of pumping test data by means of various formulas, of which the most widely used is the nonequilibrium formula developed by Theis. The development of the formula was based, in part, on assumptions that the aquifer pumped is of infinite areal extent and of uniform permeability. Stallman presented a modification of the Theis formula to extend its application to situations in which the pumped formation is adjacent to another formation of a vastly different transmissibility and the boundary between the formations approximates a straight line. Stallman's modification and the analytical procedures described by Brown for analyzing data from aquifer tests involving boundaries are based on the image well theory, according to which the hydraulic effects actually caused by the geologic boundaries may be theoretically ascribed to strategically placed imaginary wells. The application of the image well model makes it possible to treat a problem involving boundary conditions like one of a multiple‐well system in an infinite aquifer. Methods and procedures outlined by Stallman and Brown make possible the solution of problems involving one boundary; the hydraulic system may be balanced by the proper positioning of one image well. The resultant drawdown patterns have been described by Lang. The article presents the Theis nonequilibrium formula, along with a hypothetical example.