Modernization of the API recommended practice on rheology and hydraulics: creating easy access to integrated wellbore fluids engineering

Tailoring drilling-fluid hydraulics is one important key to the success of a drilling operation. Failure to do so, can result in costly problems, negatively impact equipment longevity and performance, as well as ultimately jeopardize overall well objectives. In recent years, the industry methods have deviated from American Petroleum Institute (API) RP13D standard practice (2003, 2006). This departure has been driven primarily by the increasingly onerous demands of critical wells, coupled with readily accessible computer power. In 2003, a task group was formed to modernize the existing API recommended practice (RP) bulletin on rheology and hydraulics. It comprised a cross-functional team of operators, suppliers, and academics that set an aggressive target to modernize the existing standard within 2 years. The focus was to develop simple, yet accurate, methods that could be implemented readily with basic spread-sheeting skills. This paper describes improvements made to the existing procedures and provides an illustration of how these methods can be applied to complex well designs. The paper also serves to introduce the industry to a modernized API standard that offers an ideal foundation to inform new engineers of the fundamental concepts of hydraulic design and optimization.