Enhancing Safety and Contingency in Well Operations: The Power of Casing Magnetization

During oil and gas drilling, ensuring safety of the well operations is paramount. Uncontrolled blowouts pose significant risks, necessitating solutions for well control and contingency planning. One such breakthrough method gaining traction is the pre-magnetization of casing, a cost-effective strategy that not only enhances safety but also streamlines the process of relief well drilling.

The Challenge

GPS signals, while invaluable on the surface, lose their effectiveness underground. Satellites do not have a clear line of sight, prompting the need for alternative methods for localizing and locating wellbore positions in case of a blowout.

The Solution for Contingency Planning and Relief Well

Enter casing magnetization—a method employed to create a detectable magnetic field around the casing. This magnetic signature becomes crucial during emergencies, particularly in scenarios involving uncontrolled blowouts. By magnetizing the casing, a strong magnetic hole is formed, providing a reliable reference point for equipment localization.

The Process of Casing Magnetization

Position measurement using a compass is possible, but the magnetized casing introduces a significant enhancement—a distinct magnetic field or “strong pole.” This enhanced magnetic signature is critical in the event of an uncontrolled blowout. In such a situation, if a new well needs to be drilled to intersect with the blowing wellbore, the magnetized casing becomes instrumental.

The process involves moving a coil onto the pipe and applying high voltage and current to magnetize the joint. Afterward, the power is turned off, and the coil is repositioned, repeating the magnetization process. Crucially, it is imperative to measure the magnetic field post-magnetization, assessing it at various positions along the pipe. This meticulous approach ensures the reliability of the enhanced magnetic field for accurate wellbore localization and subsequent well control measures in case of a blowout.

AGR experts have applied the method successfully since 2009, with approximately 40 wells benefiting from this innovative approach.

Efficiency and Low-Cost Benefits

Casing magnetization emerges as an efficient and cost-effective solution for contingency planning and relief well planning. Magnetizing the casing in advance proves to be a cost-efficient approach to amplify the detectable range when employing passive magnetic ranging (PMR) techniques. This method is particularly advantageous when dealing with challenging well conditions such as shallow wells, dense fields, salt formations, or when active magnetic ranging (AMR) is less suitable.

Enhanced Detection Range

After pre-magnetization, the detection range typically expands from less than 10 meters to 20 meters or more when ranging for a casing shoe. This range further increases when aiming for the middle of the casing. This expanded detectable range is instrumental in well-avoidance measures, shallow relief well intersects, and scenarios where PMR is the preferred ranging technique.

Documentation and Quality Assurance

Casing Magnetization Services (CMS) goes above and beyond by providing detailed documentation of magnetic field strength for each joint before and after magnetization. Every joint is properly marked, and the final report outlines the specific order in which the joints should be installed in the wellbore. This meticulous approach ensures the effectiveness of the magnetization process.

Conclusion

Casing magnetization stands as a testament to our industry’s commitment to safety. By adopting this method, drilling operations not only mitigate the risks associated with uncontrolled blowouts but also enjoy a streamlined and cost-effective approach to well control.

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