Gas Cap Water Injection Enhances Waterflood Process To Improve Oil Recovery In Badri Kareem Field

Abstract

The Badri Field in the Gulf of Suez of Egypt contains two major producing reservoirs, the Miocene age Belayim and Kareem reservoirs. The Kareem reservoir with a large gas cap was the initial horizon produced in the Badri Field, beginning in May 1983. By the end of 1984, ten wells were put on production. Within two years, gas production increased rapidly from initial solution GORs of 600 to 10,000 SCF/STB. Due to concern that continued production would result in accelerated gas cap drainage and poor oil recovery, most of the Kareem wells were shut in and recompleted in the overlying Belayim horizon. In 1993, a computer simulation of past and future pressure and production performance was completed to optimize the oil column recovery in the Kareem reservoir. Based upon this model study, a waterflood development of the oil column was initiated in mid-1993 with the drilling and recompletion of six production and three injection wells. However, even this extensive program is projected to recover only about 28% of the OOIP. To further improve future oil recovery, the computer model simulation for this reservoir was used to see if an alternative method could be implemented. Gas cap water injection was identified, researched, and then simulated in the Badri Kareem reservoir model. In May 1995 gas cap water injection was initiated in four wells, so to create a wall of water along the northern, southern and western edges of the gas cap. This wall of water will separate the gas cap from much of the oil column. Introduction With a model estimated ultimate primary oil recovery of only 24% through the year 2018, the Badri Kareem reservoir contains a significant resource base which has been underdeveloped due to concerns about excessive gas cap production. With this in mind, a waterflood development project was initiated in mid-1993 to improve production. However, even the waterflood development project is anticipated to improve the ultimate recovery to only about 28% OOIP. Therefore, thought was given to what additional process could be used in this reservoir. Gas cap water injection was identified, researched, and then simulated in the Badri Kareem reservoir model. Figs. 1 and 2 are areal and cross-sectional sketches (not to scale) of how the gas cap water injection process is to work in the Badri Kareem reservoir. Fig. 1 shows how water injection into the Badri Kareem gas cap along a line of four gas cap water injection wells will create a wall of water along the western edge of the gas cap. This wall of water will separate the gas cap from much of the oil column. Little well development on the western side of the reservoir has left most of the remaining reserves in this western area. Fig. 2 is the cross-sectional sketch showing how the wall of water will limit gas production in the oil column production wells and oil intrusion into the gas cap by creating a barrier between them. This also will allow for the optimization of the water injection into the oil column and aquifer. Structure The Badri Kareem is an elongate, north-northwest trending anticline at a depth of about 6,000 feet with approximately 600 feet of closure at the top of the Kareem formation. Fig. 3 shows the Badri Kareem structure map. P. 25^