The standard well-completion method in the Valhall field has evolved since 1996 to include multiple proppant fractures along the horizontal laterals. Coiled tubing (CT) has been used since then to perform over 200 post-fracture proppant cleanout operations. Field practices were developed from these jobs but the process in different stages of proppant cleanout operations had not been systematically optimized to realize best performance until the launch of a new process to optimize CT proppant cleanouts.

In May 2004, a study of proppant cleanout process optimization was completed by analyzing historical cleanout performance and incorporation of a new, integrated wellbore-cleanout system to improve operational efficiency through optimized processes, improve safety and reliability by implementing standardized procedures, and reduce stuck-pipe potential through improved design. This study analyzed the whole process of proppant cleanout, captured best practices through validation of field experience, introduced innovations to routine operations, and engineered a new, more efficient cleanout procedure for field operations.

The field implementation of this new process optimization on the first three wells, a total of 22 zones, indicated a significant performance improvement. The optimized process saved a total of 6 days’ working time and encountered zero incidents that might have led to stuck pipe. The new cleanout procedure was followed by different operational crews on the job and has been adopted as a best practice for future wells.

This paper details the engineering and implementation of CT post-fracture proppant cleanout process optimization in the Valhall field and demonstrates a step-change improvement in Valhall CT cleanout performance during the past 9 years.

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