Advancements in drilling control system technologies enable gains in efficiency and repeatability. Recent developments also frequently include automation. To achieve these improvements, the industry is developing and introducing new control tools with rapid speed. However, not all drilling contractors are able to leverage these new advancements in machine controls.

Capitalizing on the new technologies requires that drilling rigs are running current generation Alternating Current (AC) drawworks and are fitted with controls system architecture suitable for this generation of hardware. Simply put, the industry is not developing Digital and Automated Drilling Control technology for dated, legacy drawworks run by direct current (DC) silicon-controlled rectifier (SCR) systems. This is a problem for many rigs in the fleet.

Because these rigs have antiquated hardware, they cannot be outfitted with the latest control systems without being upgraded with AC hardware platforms and equipment. This leaves many rigs lacking features and technologies that make them more capable and more competitive. Upgrades require an investment, and the cost and time associated with making hardware changes has been a barrier to entry for drilling contractors eager to capitalize on the new controls system technologies.

Historically, converting an SCR rig to AC technology required that the rig be rebuilt entirely. There are obvious incentives for upgrading ageing rigs, but the traditional approach to carrying out an upgrade is too time- and cost-intensive. The industry needs an affordable way to upgrade outmoded assets that can be implemented without resulting in extensive non-productive time (NPT) or lost revenue.

A new approach has been introduced to simplify the process. By swapping the existing direct current (DC) top drive and DC drawworks with AC models and adding a compact driller's cabin equipped with built-in drives to power and control the top drive and drawworks, an upgrade can be performed during a rig move. Using this upgrade method, an older rig can be outfitted to interface with new technologies to capture efficiency gains within a significantly shortened timeline.

This solution is feasible, but to enable execution, all upgrades must be tailored specifically to the rig layout. Before any work can be undertaken, thorough pre-planning discussions must take place among the parties involved, including management, finance, engineering, operations, and project execution teams.

A recent upgrade carried out during a rig move for a 2,000-horsepower class rig working in Saudi Arabia demonstrates how a field- retrofit solution makes it possible to quickly and cost-effectively convert any SCR drilling rig to AC without incurring extensive NPT.

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