Application of Simulation Techniques to Low Permeability Reservoirs

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract This paper represents an effort to apply simulation techniques to low permeability gas reservoirs. Problems encountered are illustrated by an actual field example. Techniques normally employed for gas reservoirs are not easily extended to the low permeability case. The results show that it is permeability case. The results show that it is possible to rigorously calculate the possible to rigorously calculate the performance of such reservoirs, but to do performance of such reservoirs, but to do so requires data that make application to large fields impractical. However, certain adjustments can be made that approximate performance of such reservoirs, making large performance of such reservoirs, making large applications possible under some restricted conditions. Introduction Natural gas transmission companies must invest millions of dollars in surface pipeline systems and compression facilities in pipeline systems and compression facilities in order to produce natural gas and transport it thousands of miles to the market area. These surface systems are designed to fit the specific reservoirs with which they are connected. In the mid-continent gas supply area, and specifically the Anadarko Basin, many gas reservoirs are characterized by low permeability. Reasonable gas rates that permeability. Reasonable gas rates that satisfy both the transmission company's market requirements and the producer's economics result in large pressure transients existing over extended periods of time. While the pipeline company is basically interested in stabilized well performance, the individual well rates are often determined by short term transient well tests. This makes it necessary to calculate both highly transient and stabilized flow. Numerical simulation techniques would appear to offer the best solution to such a problem. This paper deals with experience gained from simulating a low permeability reservoir and is illustrated with an actual field example. THE PROBLEM AND DATA AVAILABLE The simulation of gas reservoirs in the Anadarko Basin requires consideration of low permeability. The extension of techniques permeability. The extension of techniques used for high permeability fields has proved to be not entirely adequate. This study represents an effort to calculate the complete performance of a reservoir that is characterized performance of a reservoir that is characterized by low permeability, then to develop a technique to evaluate such reservoirs in a routine manner.