Simple but Effective: A Case History Demonstrating Enhanced Performance and Simplified Logistics from New Rotary Steerable

Abstract

Based on input from key operators in the Middle East region, a new rotary steerable system (RSS) was launched after a compressed development schedule. This paper describes the development and introduction of the larger tool sizes needed for both onshore and offshore hole sections, including hole sizes from 12 in. and up, in the Middle East. It also outlines the deliberate design of the tool for local assembly and repair.

Large diameter (9-1/2 and 11 in.) RSS designs used an existing, smaller design for Middle East applications in both offshore and onshore wells as a basis. When designing these new sizes, engineers took note of lessons learned with smaller sizes of the tool and incorporated design elements for local manufacturing, assembly, and repair. The resulting simple, modular construction enables increased levels of local content and provides for significant reductions in transportation, and therefore associated emissions.

Of course, although local content and sustainability are highly desirable, performance is essential, and this paper describes case histories demonstrating how well the new tool worked in real-world Middle East applications.

In one notable example, the newly introduced 9 1/2-in. diameter RSS was used to drill an offshore section in the Gulf of Arabia. The tool was mobilized after two older generation RSS had become stuck for days. Consisting primarily of argillaceous limestone, the formation had a history of stuck-pipe events. The new RSS was recommended for this application because of a slicker construction, with a fully rotational bias unit, minimal bottom hole assembly (BHA) stabilization, and an optimized junk slot area, which together help to reduce stuck-pipe risks. The tool drilled to the target depth in a single run, thereby achieving all directional requirements. Notably, after reaching the target depth, the assembly was tripped out of the hole without any requirement for backreaming. This seamless exit, in turn, indicated achieving a smooth wellbore.

Other case histories demonstrate results with both new sizes of this tool. The paper also discusses in detail the ability to repair locally and engage the local supply chain.

Specifically with Middle East applications in mind, a new, simple RSS design in large diameter versions has demonstrated success in offshore and onshore applications across the region. The design has also proven capabilities for manufacturing and repair local to operations, which enables maximizing in-country value, optimizing use of the tools, and energizing local supply chains.