Zero Waste Well – the beneficial use of produced water from CSG projects

Abstract

Most onshore gas provinces in Australia are in remote locations where it is expensive to bring materials to, and take waste away from, well sites. Importantly, water is not only an input to, and a product of, the drilling, completion, construction and production process, it is also a precious resource. That is why Santos has been working towards the ‘Zero Waste Well’. Historically, separate drilling, completion, construction and operational teams were involved in sourcing and disposing of water without taking a holistic view of the water cycle. By taking a collaborative approach and looking at the complete water cycle, Santos has been able to reduce its water use and eliminate wastewater by reusing all of the produced water in its Queensland coal seam gas upstream activities for beneficial purposes. As part of the Zero Waste Well concept, Santos has identified and implemented a range of initiatives for beneficially reusing produced water. These include stock watering, construction, dust suppression, rehabilitation, and drilling and completion activities. One of the most exciting innovations is to beneficially reuse produced water for localised irrigation. This avoids or minimises the need for large centralised water gathering systems and large static centralised water storages and treatment plants. This also minimises the environmental footprint, energy intensity, carbon emissions and brine wastes from Santos’ activities. Localised irrigation not only reduces construction and operating costs, and engineering design and construction timeframes for Santos, it provides a valuable pasture irrigation source for local landholders.