An Application of Mathematical Modeling of Dissolved Gas Reservoirs with Minimum Available Data
Authors: Vest Gary L. , Agnew J.B. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion 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 discusses estimation of future recovery from a dissolved-gas reservoir where it is generally necessary to assume various reservoir data that have not been taken, that are not available or whose accuracy is questionable. In this study, past production performance is matched on an individual well performance is matched on an individual well basis through the use of a two-dimensional two-phase, mathematical reservoir model. By obtaining a production history match, it was found that a reliable estimate of future performance may be obtained performance may be obtaine

Introduction
With the discovery in recent years of the ultra-deep, large volume non-associated gas reservoirs, there may be a tendency to minimize the contribution of casinghead or dissolved gas in satisfying the total U.S. gas requirements. However, in Texas Railroad Commission Districts 7C and 8 during 1966 approximately 785 Bcf of casinghead gas was reported to have been produced. This volume represents about 53 percent of the total gas produced in this area. Much of this casinghead produced in this area. Much of this casinghead gas is sold to gas pipeline companies for transmission to various parts of the U. S. To anticipate future needs, a gas transmission company must be able to forecast the future gas availability from all present sources. Therefore, since casinghead gas is supplying a significant percent of the total gas requirements, a need percent of the total gas requirements, a need has developed for a method that will accurately forecast the future availability of gas from these sources.
Many methods for predicting the future gas availabilities from dissolved-gas drive reservoirs have been presented in the literature. However, the amount and quality of pertinent reservoir data necessary to their solution may somewhat restrict their use. Also, these solutions are generally on a total reservoir basis, assume homogeneity, and do not forecast individual well performance.