BP-Egypt utilized AGR’s RMR technology onboard the Jack-up rig Constellation II on the Rahamat-1 well in the Mediterranean Sea. On the top-hole drilling campaign, AGR’s RMR system pumped the drilling fluid and cuttings from an outlet in the conductor 10ft above sea level with returns to the rig for recirculation. The RMR has previously been used exclusively on semi-submersibles.
The conductor could not be driven below 50m BML due to firm sand. This, combined with the large 45m airgap, resulted in a shoe strength of less than 0.8 SG RKB equivalent. It was impossible to pump seawater up the conductor to the rig and the next section needed 1.2 SG inhibited mud. RMR provided a closed system with engineered mud returned to the rig while keeping the bottom hole pressure below fracture pressure. The alternative solution would have been to add an extra liner with a price in the area of $2-3million.
BP-Egypt’s Engineering Team Leader Edvin Kvalvaag commented “We have been very pleased with the technological solution AGR provided. The RMR system enabled us to eliminate the challenge of the large air gap and weak conductor shoe, it also provided better hole stability as engineered fluid could be used.”
BP-Egypt contracted AGR Drilling Services to develop a new interface and deployment procedure for mud recovery, based on their existing Riserless Mud Recovery (RMR) technology. The system collected all fluids and cuttings during the top-hole drilling process and returned them back to the flow line on the rig for recirculation.
The system incorporated a docking solution of the suction hose towards the existing conductor, a powerful subsea slurry pump and a return hose system. All components were powered and controlled electrically from the surface. There was no work-class ROV installed on the rig and all subsea connections were eliminated from the design. Despite this challenge, the project was executed successfully.
AGR’s Project Manager Kjartan Seim commented, “The new system was developed to minimise the mud column to enable a reduction of the pressure at the conductor shoe. This also allowed us to improve the mud specifications to meet the challenging well formation. We are grateful for the trust BP has placed in us, and are pleased that this project was completed successfully on time and within budget”.
(AGR Press Release)