How To Maintain The Production Of The Salty Oil Wells'

Many fields in Algeria produce the salty oil. Depending on the quantity of salt contained in the oil, there are some technical solutions to improve the quality of oil by reducing its salinity. These solutions pass from the simplest washing of the crude oil by fresh water to the specific facilities. In this paper, I would like to highlight the risks associated with the two systems of assisted production (gaslift and pumping), under particular conditions, in order to ensure continuity in the production of wells. The great salinity of produced water and the salt depositing which could appear at the bottom of the wells and in the tubing are the principal concerns for which it is necessary to face to ensure a good production of these fields. The high salinities (360 to 380 g/l) exist in Triassic reservoir on the nearby fields of Hassi – Messaoud (El-Gassi, Haoud- Berkaoui, NGoussa…). The low salinities of 150 g/l, for example, are encountered on the Carboniferous in Zarzaitine field (Illizi basin). So, actions to prevent salt problems would be different, for different salty water concentration. The GOR from the Triassic reservoir is relatively high and the quantities of produced gas are important. This factor must be considered in the choice of artificial lift system. I was interested, in this paper, in the fields of Block 438 B (see map - Fig.1), for which the final choice of assisted production system is not yet fixed. These fields, scattered over an area of 4365 km², must be fully assisted in a time not exceeding six years after their first commissioning. According to reservoirs studies, only the third of production of these fields will be produced by natural flowing. The remaining reserves will be produced by artificial lift for at least 20 years. The choice of artificial lift system (gaslift or pumping) is very important to insure the maximum of oil recovery.