November 2008
Petroleum Economist in Fundamentals of Oil and Gas in the Middle East
Publication
An holistic approach to water supply and effluent disposal
In upstream operations worldwide, oil companies produce three times as much water as oil, some 250m b/d. Determining the best option for water disposal is crucial. Water that comes to the surface in oil-producing wells is usually referred to a produced, or effluent water. Oil companies often re-inject that water back into oil reservoirs for reservoir-pressure maintenance, a technique called produced-water re-injection (PWRI). Alternatively, it may be discharged into the sea, rivers, or lakes, or into underground zones or aquifers at shallower depths than the source-oil reservoirs, known as disposal wells. In the upstream industry, water is also used for:
Water is also used in great quantities in downstream oil processing, creating large amounts of slightly contaminated wastewater, at many intermediate stages in pipeline hydro-testing and, among other uses, as tanker ballast waters.