ESTIMATING THE STORATIVITY OF THE ARBUCKLE-SIMPSON AQUIFER FROM THE ANALYSIS OF NATURALLY-INDUCED STRESSES-STRAINS

The objective of this research is to estimate the storativity of the Arbuckle-Simpson aquifer using transducer data. The aquifer is located in South-Central Oklahoma, United States of America. The Arbuckle-Simpson aquifer consists of fractured limestone, dolomite, and sandstone of the Arbuckle and Simpson Groups of late Cambrian to middle Ordovician age. The thickness of the water-bearing formations is approximately 3000 ft. The surface area of the aquifer is over 500 square miles.

Aquifers are subjected to mechanical stresses from natural, non-anthropogenic, processes such as atmospheric pressure loading or mechanical forcing of the aquifer by ocean tides and earth tides. Fluctuations of ground water pressure due to these stresses are often reflected in the records of water level monitoring wells. Analyzing the aquifer water level or pressure fluctuation to determine storativity constitute an attractive alternative to pumping tests and other traditional methods to study aquifers. The research is based on the analysis of the aquifer-well system problem, in which pressure oscillations causes macroscopic water movement into and out of the well. The pressure oscillation is the product of the atmospheric-pressure fluctuation and the dilatation caused by the earth tides. Water level fluctuations from an open well penetrating a confined aquifer are analyzed and its amplitude and phase angle is resolved. The amplitude and the phase angle of the water level fluctuation along with those of the theoretical tide potential are the basis for the computation of storage coefficient.