Estimation of Primary Oil Reserves for Lansing-Kansas City Reservoirs

Kansas Waterflood Symposium of the Society of Petroleum Engineers of AIME,19 November, Great Bend, Kansas Abstract The purpose of this paper is to present a method of making initial primary reserve estimates for Lansing-Kansas City reservoirs occurring within the confines of the Central Kansas Uplift. Hypothetical charts presenting reservoir fluid characteristics were prepared, based upon the comparison of a reservoir fluid sample and previously published fluid correlations. The method of predicting primary reserves is based upon the past performance of a number of Lansing-Kansas City wells. Also presented are formulae which permit the calculation of reservoir saturation conditions during, or at the end of the reservoirs primary life, which are necessary before reliable secondary estimates can be made. Introduction The initial estimation of primary oil reserves for a Lansing-Kansas City reservoir is in most instances a difficult problem for the petroleum engineer to solve. This difficulty arises not from a difference in production or reservoir energy concepts, but from the fact that the reserves discovered do not justify the collection of sufficient engineering data such as core analysis, relative permeability ratios, reservoir fluid samples, pressure histories, etc., to permit a reserve evaluation of these predominately undersaturated solution gas drive reservoirs, by normal material balance methods. Therefore the purpose of this paper is to present correlations of the various reservoir fluid properties of the Lansing-Kansas City crude in conjunction with a method of making initial primary reserve estimates that is based on the past performance of a number of Lansing-Kansas City reservoirs. Reservoir Fluid Correlations Prior to making reservoir calculations a knowledge of the physical properties of the reservoir fluid is required. This data is best obtained from the PVT analysis of a sample of the reservoir fluid, which in the case of Lansing-Kansas City reservoirs is a rarity. We are therefore forced to rely upon a correlation of some easily obtainable surface parameters with these reservoir fluid properties to permit reliable reserve calculations. Various authors have presented correlations concerned with the prediction of oil viscosity, solubility and shrinkage of numerous crude samples with various reservoir properties. In order to obtain a relationship between this published data and an available Lansing-Kansas City reservoir fluid sample, the original data presented by Katz and Beal was plotted in conjunction with this data and the published correlation curves were shifted to match the sample, as stated in the following discussion.