Fraturamento hidráulico de aquíferos – medição, modelagem e sua relação com o aumento da produtividade dos poços

Abstract

Population's demand for water has compelled the development of techniques to improve the use of all forms of water resources. In some parts of the United States hydraulic fracturing has been used to enhance the yield of wells drilled in bedrock. In Brazil's Northeast region, wells drilled in this kind of formation often exhibit low water yield that sometimes results in these wells being deactivated or abandoned. The main objective of this research is to study the effects that hydraulic fracturing causes in a fractured rock aquifer's transmissivity and flow. To this end, a model was developed that describes the propagation of fractures in a shallow, impermeable rock matrix. As a test of the methodology, data collected from two pumping wells drilled at the University of New Hampshire were used for verification. These data include pre- and postfracturing pumping tests and records of the fracturing operation. A combined analysis of pumping test results and propagating fracture model concluded that the hydraulic fracturing increased the transmissivity of one well more than 10 times and in the other the transmissivity increased 190 fold. The practical information was that one well yielded 10 times more water and the other 18 times more.