Application of Material Balance Techniques in Matching and Predicting Performance of the Heterogeneous Multilayer Hassi Messaoud Field
Authors: Miesch E.P. , Khelil Chakib 
Published: December 2007

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. 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 OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, 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 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
Material balance techniques were used to calculate the active oil represented by the build-up pressures of the individual wells in the heterogeneous multi-layer Hassi Messaoud field. The technique of Amyx, Bass, Whiting, Havlena, and Odeh were used.
This application improved the history matching phase of a reservoir simulation project that was being conducted on the field. project that was being conducted on the field. The material balance results were used as a criteria for selecting a combination of "grids" to represent each well in the mathematical model that in turn would be used to obtain volumetric average pressures for comparison with the measured data.
The study indicated areas of the Hassi Messaoud field that were obtaining vertical and horizontal oil influx. Subsequent drilling has concerned the location of this additional oil in many parts of the field.

Introduction
This study was made in conjunction with a reservoir simulation study that was recently conducted on Algeria's largest oil field, the heterogeneous, multi-layer Hassi Messoud. The field was discovered in December 1957 and is located in the Algerian Sahara Desert about 375 miles southeast of Algiers as shown in Figure 1. At this time of this study, 1971, the oil productive area was approximately 23,000 acres. Production is from the Cambrian Ri-Ra zone. The original reservoir pressure was approximately 6855 psi and the maximum saturation pressure was approximately 2900 psi. It is at a depth of about 10,500 feet subsea, and it has approximately 245 feet of net pay with an average porosity of eight percent. The average permeability to air of percent. The average permeability to air of 41.7 md was obtained by averaging the values for all samples with kair greater than 0.1 md. Reservoir rock and fluid properties are shown in Tables I and II respectively.
The Ri-Ra formation is underlain by the R2-R3, which is also oil bearing. The R2-R3 member was penetrated by only a few of the wells because of the lack of commercial production from this member. Consequently, the available data for the zone are limited.