Wireline Well Logging: An Underutilized Technique in Reservoir Evaluation

Abstract

Wireline well logs have three general uses in geothermal exploration and reservoir evaluation: reservoir parameter analysis, lithologic column determination, and reservoir size resolution. Reservoir flow testing data are acquired to understand the flow rate, life, and production potential of the geothermal reservoir. These data are a coarse subsurface measurement of the geothermal prospect. Wireline logs acquired from wells in a geothermal prospect are used to define in detail, or estimate the reservoir parameters of temperature, thickness, lateral size, amount of fracture and intergranular pore space, and the quantity and quality of fluid that might be produced. Laboratory measurements can be made on core samples and drill cutting samples to define the intrinsic behavior of the materials and fluid that compose the geothermal reservoir. Wireline log measurements are needed to correlate and link the reservoir testing an core analysis, reduce the amount of time needed for flow testing's, and predict the production life (amount of heat and fluid available) in a geothermal field.