Estimating Production Of Prospective New Wells With Log Derived Permeability Feet (Kh) Maps Available to Purchase

Predicting the volume of hydrocarbon production that a prospective new location will produce is essential in determining the various economic parameters necessary in executing the decision to drill at the most profitable time. A simple method is shown which effectively combines reservoir data and geologic knowledge with practical log interpretation to help estimate the productivity of prospective new wells. The technique appears to have its most useful application in the exploitation phase of field development. The literature contains a good variety of useful equations which can be used to equate log measurements to permeability. They all have their merits and can be used in the construction of Kh (permeability feet) maps. The technique takes advantage of commonplace reservoir measurements to help solve for the constant in one of the more general expressions which relates log derived porosity and water saturation to permeability. Core analysis, if available from control wells or a nearby field, can be used to establish a grain density for porosity calculations. Since an accurate comparison of wells is paramount, log responses are normalized when necessary. After a constant in the log-permeability equation has been established and Kh is computed from normalized log values, a map of Kh is constructed which utilizes current geologic knowledge of depositional trends and sedimentation patterns. Production is predicted from plots which relate log derived Kh vs. production over an appropriate initial time period. Kh vs. initial production rate (BOPD or CAOF) can also be plotted; however, due to different completion methods, this plot may show a high degree of variance. Kh values are read directly off of the Kh map and entered into the appropriate chart to estimate production. The conclusion is reached that such maps add extra value to log analysis and application because the results are used to estimate production before drilling commences. Thus, log analysis, which has been augmented with accessible reservoir data and local geologic knowledge provides the means by which log interpretation can be extended to help select new locations and estimate how much they will produce. Application of the method is shown for a South Texas gas field and a Wyoming oil field.