Environmental legislation governing the disposal of drilling waste is continually restricting the discharge limits of drilling fluids and drill cuttings. Operators are charged with achieving a balance between minimizing the potential environmental impact of the drilling fluid while maintaining wellbore stability. Many reservoirs by their inherent nature, as well as the performance advantages of oil-based and synthetic-based drilling fluids, often preclude the use of a water-based fluid. The resultant oleaginous-based drilling fluid and cuttings, whether they are synthetic or diesel, present a complex and costly waste management challenge.

During the planning stages of a drilling project it is important to create an Integrated Waste Management Plan (IWMP). The IWMP takes into account the various types of waste generated by Exploration and Production (E&P) operations in a given area. The key feature of an IWMP is resource management. The use of thermal desorption technology as part of an IWMP allows the recovery and reuse of valuable liquids from the drilling waste. These recovered fluids can be reused as base fluid for reconditioning or building new drilling mud, or as a fuel source.

Spent materials from drilling, completion and workover operations represent the largest volume of waste typically included in an IWMP. These wastes include drilling fluids and/or cuttings from drilling operations. Due to more stringent environmental regulations with respect to hydrocarbon discharge limits, the use of thermal phase separation (TPS) technology helps operators meet their waste management goals in a cost effective and efficient manner. The economic benefit to the operator using TPS technology is greatly enhanced by the value and cost savings associated with the reuse of the recovered fluids.

Operator A selected TPS technology to provide drilling waste management and fluid recovery for a field development project in Blocks 10 and 12 in Ecuador. Operator B selected TPS technology for the Tengiz reservoir in Kazakhstan. TPS is a technology that recovers water, oil and other base fluids that would otherwise be transported for disposal. This paper describes the IWMP approach to the planning, designing and implementation of thermal treatment for these two distinct drilling operations in Ecuador and Kazakhstan. This paper will show how the synergistic approach to waste management enabled both operations to meet all environmental and operational objectives in terms of handling and disposing of drilling waste.

The IWMP approach has proven cost effective on many drilling projects around the world. The authors will chronicle the use of thermal treatment as part of successful waste management plans on drilling projects in an eco-sensitive area of Ecuador and in Tengiz, Kazakhstan. Similar projects are under consideration for Mexico, South America, Russia, and sites in the United States.

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