Exploitation Study and Impact on the Kareem Formation, South EI Morgan Field, Gulf of Suez, Egypt

Abstract

ABSTRACT An integrated geological, petro physical, geophysical and reservoir evaluation was conducted on the Kareem Formation of South El Morgan Field. Results were directed toward developing a reservoir management/depletion program to optimally recover the field's reserves. The Kareem reservoir consists of two vertical performance compartments. The upper compartment is further subdivided by an erosional channel cut, while the lower compartment is laterally continuous. Field exploitation will involve changing the present peripheral water flood by moving the peripheral injection wells up dip and placing a pattern water flood across portions of the reservoir. Each reservoir compartment will be treated separately. INTRODUCTION South El Morgan field is located in the southern Gulf of Suez along a 100-mile trend of established offshore oil fields (Figure 1). It is one of three fields that comprise the Morgan-Badri Complex. Oil is found in two Miocene sand reservoirs, the Belayim and the Kareem (Figure 2). This study focuses on the more prolific Kareem Formation of South El Morgan which occurs at an approximate depth of 6100'. Since discovery in 1964, the Kareem sands of South El Morgan have produced over 890 MMBO. The fields are operated by the Gulf of Suez Petroleum Company (GUPCO), a partnership between the Egyptian General Petroleum Corporation and Amoco Egypt Oil Company. Subsurface logs from over 185 boreholes, limited core data, and seismic data were used to evaluate the stratigraphic and structural components of the field. Production performance, pressure surveys, open-hole log analysis and production log analysis were used in the reservoir engineering evaluation. DEPOSITIONAL SETTING The depositional setting for the South El Morgan Kareem Formation is interpreted to be a coastal fan delta. This interpretation is adopted from a field core study by Rine et al (unpublished company report). Miocene environmental conditions closely approximated the desert conditions present today in the Gulf of Suez. Sparse vegetation in the dry climate left a loose sediment cover which was easily transported in wadi or deltaic systems to the marine coast. STRATIGRAPHY The Kareem Formation is a thick clastic interval (maximum 1300') which overlies the Rudeis and is unconformably overlain by the Baba Evaporites of the Belayim Formation (Figure 2). Generally, the Kareem is composed of stacked coarsening upward sequences which represent the progradation of deltaic sand lobes over open marine mudstones. The Kareem was divided into nine stratigraphic zones. These were correlated across the field using E-log marker beds (A through I, youngest through oldest, respectively, Figure 3). Pressure? data from RFT, static and buildup surveys indicates that the Kareem reservoir functions as two vertical performance compartments. The upper compartment consists of Zones A-C, the lower compartment consists of Zones D-I. Pressures in Zones A-C range from 800 to 2000 psi; while pressures in Zones D-I range from 2000 to 3000 psi. These values vary over the field but generally Zones A-C have pressures 500-1000 psi lower than Zones D-I. The pressure differences are probably not controlled by depth alone as the formation pressures typically change abruptly at the Zone C-D boundary.