Utilization of Waste Water Stream for Heavy Oil Recovery

ABSTRACT Objective/Scope The extraction of Heavy Oil (HO) from the soon-to-be developed Lower Fares South Ratqa field requires steam injection to enhance HO recovery. The amount of water required for this facility is quite high, up to 210,000 barrels/day (in excess of 33 million liters per day), and the availability of suitable water is problematic, particularly in a dry country such as Kuwait. Enhancement of Heavy Oil (HO) recovery can be effected via cyclic steam stimulation and steam flood techniques. However, steam generation is highly dependent on the availability of sufficient quantities of suitable water. Potential water sources for steam generation include seawater, rivers, lakes or underground bodies of water. The last three are unavailable in sufficient quantities in Kuwait and specifically in North Kuwait. Methods / Procedures / Process Seawater was initially considered as a source water option for the Lower Fares Heavy Oil (LFHO) project but further investigation identified another potential water source – a Reverse Osmosis (RO) reject water stream from the Sulaibiya Sewage Treatment Plant (SWWTP) – as a feasible option. After careful assessment, KOC selected the RO reject water stream from the SWWTP as the optimal solution. This innovative application utilizes a currently discarded resource and eliminates the environmental concerns associated with discharging this resource to the sea. KOC requires up to 210,000 barrels/day water to feed the Once-Through Steam Generators (OTSG's) to produce 80% quality of steam for injection into the wells. The water treatment technologies available in the market were evaluated to ensure that the RO reject stream could be successfully treated to achieve a suitable water quality for steam generation. Results, Observations, Conclusion The LFHO Project will utilize the SWWTP RO reject stream to enhance HO recovery in North Kuwait. The discharge of this stream to the sea is currently considered as an environmental concern. The use of this reject stream was previously not considered possible as no potential usage opportunities were identified. This paper covers the usage of this RO reject stream as the source water for steam generation for enhanced HO recovery. Novel/ Additional Information The use of RO treated water streams in the petroleum industry as make-up water for cooling water towers and cleaning applications is fairly common. The use of an RO reject water stream for steam generation to enhance HO recovery is a novel application for the petroleum industry.