Downhole Tool Design Challenges for Deep Water Highly Deviated Wells

Abstract

The evolution of the offshore oil and gas industry has resulted in operators drilling multiple wells from single platforms targeting more challenging reserves in deeper waters. This progression has introduced many new technical challenges for the downhole tools used in conventional processes. These challenges must be addressed to maximize operational efficiency in these extreme service environments. This paper specifically discusses some of the shortcomings that have been identified in downhole tools currently used in offshore operations and presents a few recently released technologies specifically designed to address some of the challenges posed by the new offshore environment. Case studies including the impact of the new technologies on operational efficiency are presented.

Wringing effect prevention on a piston design in a downhole drilling tool

“…The oil and gas industry consistently requires new and improved tool designs that can address specific needs for challenging drilling applications. These designs are often operated in the hostile downhole conditions of extreme load, pressure, flow, and temperature; these conditions [1] can affect tool performance in ways which are difficult to predict [2]. More specifically, these tools are frequently used in oilfield operations such as drilling, logging, reaming, coring, and stimulation.…”

“…Therefore, it is critical to validate and verify the performance of tools under the specific operating conditions; it is also essential to understand the functional limits of the tools so that safe operating procedures can be determined. These technical challenges must be identified and addressed during the development of new downhole tools to meet design specifications for the downhole environment [1].…”

“…Intelligent downhole tools often require moving mechanism designs, such as pistons. For example, reamers use moving mechanisms to extend or retrieve cutting blocks [3, 4]; coring has moving pistons to control rock sampling barrels [5], and the packer system incorporates moving valves [1]. The moving parts or pistons rest on a mandrel, or non‐moving parts, in the default position; in downhole, after receiving a real‐time command, the moving parts initiate motion and separate from the static mandrel.…”