In an industry where the technical demands on a drilling fluid are ever increasing, the use of invert emulsion fluids has been seen as a necessity to meet required drilling performance criteria. At the same time there is increasing pressure to comply, and even exceed, the tightening environmental demands on our industry which has made the use and associated waste treatment of these invert fluids complex and costly. A drilling fluid, which has the drilling performance characteristics of an invert emulsion fluid, but can exhibit the benign environmental characteristics of a simple water-based fluid, has long been the goal of fluids development.
This paper describes the development and application of a unique water-based fluid that utilizes a triple inhibition approach to delivering invert emulsion-like drilling performance. Each component of the fluid system has also been designed to ensure compliance with some of the world's most demanding environmental requirements. The resulting fluid is flexible in formulation such that it can be utilized in freshwater on land wells to meet chloride discharge requirements, can be formulated in seawater for shelf wells to meet low toxicity and logistics requirements, and can be formulated in saturated salt water to meet toxicity and performance requirements for deepwater environments.
The applications of this fluid on a global basis will be evaluated, comparing the drilling performance and economics to offset wells which have utilized both conventional water-based fluids and invert emulsion fluids.