Development and Application of a Large-Hole Rotary Steerable System: Accelerating New Technology Introduction through Successful Collaboration

Abstract

Abstract This paper describes the successful introduction and application of a rotary steerable system for large hole sizes (17.5 and 18.25-inch.). The development of the large hole rotary steerable capability was seen to be mutually advantageous to both BP and Schlumberger. As such, this technology development was advanced as a collaborative effort. At the outset, the collaboration team identified the technology as being suitable for the intended application. Together, team members focused on the rapid development, construction, and field-testing of the rotary steerable system. Over a 9-month period, the system was designed, tested, and deployed by teams working concurrently in the UK and the USA. Prior experience gained with smaller hole sizes was used to design the system, including both the bit and the steering unit. The approach taken by BP asset teams in the Gulf of Mexico and Schlumberger contributed to accelerated initial field testing of the system in January 2002. Initial field trials proved successful. In its first application, the system was used to kick off from vertical, achieving a build rate of more than 3°/100 ft. Subsequently, the system has proven beneficial in other projects, and the value of the collaboration has been clearly demonstrated. Introduction Rotary steerable systems have progressed dramatically over the past few years as their reliability has improved and the range of applications has increased. The benefits of these systems are well documented. It has become very clear in recent years that the systems play not just a major role for drilling through the reservoir, but also, in optimizing drilling performance to the reservoir. The combination of improved rates of penetration, reduced stuck pipe incidents, enhanced hole cleaning and better hole quality have all contributed to the adoption of these systems in preference to traditional directional assemblies that use motors. Until recently, the primary hole diameters that could be drilled using rotary steerable systems ranged from 8–1/2 inch to 12–1/4 inch. As deepwater exploration and development projects have accelerated around the world, the need to improve drilling efficiencies in top hole sections has become more and more acute. It was such an application that created the impetus for the development of a rotary steerable system for hole sizes up to 18–1/4 inch. The BP Thunder Horse project is one of the most challenging to date in the Gulf of Mexico. Water depths in this deepwater development exceed 6,000 ft (1,829m). The project includes plans for a large number of wells with vertical depths approaching 25,000 ft (7,620 m). Some of these contain the further challenge of drilling significant sections of salt. Drilling teams from BP immediately recognized the potential benefits of rotary steerable systems for the Thunder Horse project, as well as, other deepwater big-hole applications below surface casing. The decision for BP to participate in the project was generally made based on the value observed in using rotary steerable technology in smaller hole salt drilling applications. The specific decision to engage Schlumberger in this effort was made based on confirmation of the ability of a pre-existing rotary steerable system to perform well in the salt. This confirmation was obtained in a very successful 12–1/4 inch salt drilling trial in a Gulf of Mexico well. This collaborative technology development project is similar to others at BP. Working together, the business unit and the Upstream Technology Group had identified rotary steerable technology as the preferred solution for salt drilling. Schlumberger, for their part, identified this addition to their rotary steerable porfolio as having commercial potential. In order to accelerate the engineering, testing and field implementation of a system, BP and Schlumberger entered a formal collaboration.