As part of Saudi Aramco's continuous commitment to conserve the ground water, this initiative will conserve more than 744 MBD of ground water. This can be achieved by reusing the abundant disposal water available onsite as power water injection for reservoir pressure maintenance. The target is to conserve the Kingdom's precious ground water while maintaining crude production.
The produced or disposal water at Qatif is untapped resource with great potential as an alternative source to replace the valuable Wasia ground water to maintain pressure in C, D and F reservoirs of Qatif field. However, this formation water separated from LPPT, HPPT, LPDT, dehydrators, desalters and other separation units in the Qatif plant contains variable amounts of oil contaminant and suspended solids.
To maintain good/long-term injectivity of disposal wells in Qatif field, water quality this formation water to be treated to meet the oil reservoir injection specifications. The Injected disposal water should be clean to avoid the adverse impact on well injectivity.
Maximum oil-in-water content to be less than 20 ppm (wt).
Maximum total oil and suspended solids (TSS) to be less than 50 ppm.
Mean particle size of suspended solid shall not exceed 5 micron.
In this study, disposal water samples collected from Qatif water-oil separation plant (WOSEP) were characterized for TSS, oil content and key ions composition. Coreflood tests were carried out on reservoir core plugs at reservoir conditions (temperature of 220 °F and a pressure of 3,000 psi) to assess the effect of this disposal water on core permeability and required filtration to improve its injectivity. Also, several water treatment proposals were identified to meet the reservoir injection specifications. The expected OPEX and CAPEX benefits of implementing the best option are:
Ground water conservation of up to 744 MBWD.
Power cost saving of up to 36 MW.
Minimize capital cost by avoiding the installation of two additional WOSEP vessels, six new large pumps, new water injection network and the drilling of 10 additional disposal wells.