Geological Factors Influencing Well Productivity on the Georgia Piedmont

摘要

Within the crystalline rocks of the Georgia Piedmont and Mountain districts the probability of obtaining a high productivity well is greater in schists, quartzites, mafic and ultramafic rocks, and graywackes than in granites, gneisses, phyllites, cataclastic, and volcanic rocks. In all rock types well specific capacities and productivities are negatively correlated with well depth, which explains 35% of the variation in the productivities of 250 wells. Analysis of a sample of 30 wells indicates that well depth increases and specific capacity and productivity decreases significantly with increasing distance from a fracture trace intersection mapped from aerial photographs. Some 70% of the variation in well productivity is explained by a model.