Single-Trip Multistage Proppant Fracturing System Reduces Operational Time and Cost to Enable Cost-Effective Production of Tight and Low-Permeability Reservoirs on the Norwegian Continental Shelf

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Abstract As part of a strategic initiative to increase production from low-permeability mature assets on the Norwegian Continental Shelf, a single-trip, multistage proppant fracturing system was developed. A frac service tool assembly (STA) is deployed on a dedicated work string, and the fracs are pumped before installing the upper completion. With a new frac head concept, the system set a record for stage-to-stage frac time, achieving targets for reduced costs, operational time, and health, safety, and environmental (HSE) exposure. Following several successful single-stage frac jobs in the field, a horizontal well was planned in the lower part of a low-permeability formation. A higher permeability formation at the top of the reservoir would be drained through multiple transverse fractures. An uncemented liner with frac sleeves and open-hole packers was designed for the completion. Detailed pre-job meetings were held with all involved parties to establish the requirements for the multistage frac system and fracturing program and to build procedures and contingencies for various stages of the operation. The well was completed and stimulated in autumn 2022, with three proppant fracs placed in a single trip. The three stages were pumped as per the frac program. The under displaced slurry volume was reversed out before moving to the next zone. After stimulation, the upper completion was installed, and a wireline tractor was used to shift open the frac sleeves in a single trip. The new frac head stand was rigged-up and down in only 30 minutes, compared to 10 hours with a conventional frac head design. This greatly reduced time between stages and working at height and in the red zone. In addition, there were fewer potential leak paths, reducing the potential for downtime. The well was a successful proof of concept for stage efficiency, exceeding the target of performing two frac stages within a 24-hour period. Further efficiency gains could see stage time reduced to achieve up to four stages within a 24-hour period. A new well with seven stages is planned to be drilled and completed in the summer of 2024 using the same concept. This paper presents the successful use of a newly developed single-trip multi-frac system. The system demonstrated a proof of concept for the further development of tight and low-permeability mature assets. Several new wells, including subsea wells, are expected to use this technology.