Integrated Reservoir Description and Flow Performance Evaluation of Self Unit, Glenn Pool Field

Abstract

Abstract This paper presents reservoir characterization results of a mature oil field followed by a successful flow simulation. The study area is the Self Unit (160 Ac) in part of the Glenn Pool field, which was discovered in 1905. Since discovery, the Glenn Sand reservoir has only produced 20% of the original in place. Under the sponsorship of the Department of Energy, a methodology is being established to produce additional oil from the reservoir in a cost effective manner. The first step of this process is to generate an integrated reservoir description followed by a successful comparison between historical performance and the simulated performance. The details of this step are presented in this paper. Introduction A successful reservoir description requires that all the available information be integrated in characterizing reservoir properties. Although the ultimate goal may be to describe the petrophysical properties on a grid block scale, it is imperative that these properties be consistent with the geological interpretation of the reservoir. Various methods of stochastic conditional simulation have been used for reservoir description. The required information for simulation is obtained from well logs and cores. The data collected represent but a fraction of the enormous volume of the reservoir. The simulation carried out just on the basis of petrophysical information does not contain any information provided by a geologist. It is fairly common to analyze the well bore data without considering different sedimentary facies that might be represented in the zone of interest. Disregarding sedimentary facies may be tantamount to mixing two populations, and this may yield erroneous estimates. A better reservoir model can be developed if the reservoir properties are described based on geological architecture 9 Geological information should be made a part of the conditioning data. By using this information a more accurate reservoir description can be constructed which is geologically defensible. This is a parallel approach where qualitative and quantitative constraints are imposed on the reservoir by combining geologic and engineering information. This work involves the use of geostatistical techniques to combine geological and petrophysical information for reservoir description. The study was conducted on the Self Unit" (Fig. 1) located in southern part of Glenn Pool field in northeastern Oklahoma. The description was used as an input in a flow simulator to compare the simulated performance with the historical performance of the unit. The project is jointly sponsored by the DOE and Uplands Resources Inc., an independent operator, as a part of the Class I program. Background Glenn Pool oil field produces from Middle Pennsylvanian (Desmoinesian) age Bartlesville sandstone. P. 127^