High-Pressure Filtration Unit for Completion and Workover Fluids

Abstract

Debris management is essential to successful completion operations. A High-Pressure Debris Unit (HPDU) was developed to maintain a solids-free environment during completion and workover operations. The HPDU protects downhole tools and equipment by keeping completion fluid and workover fluids free of damaging debris. The HPDU is utilized after the remaining drilling fluid is displaced by completion fluid. The system has repeatedly demonstrated its value in preventing foreign objects from entering the wellbore. Debris is removed from pits, valves, pumps and other equipment before those solids can enter the wellbore. The HPDU system is installed at the standpipe and comprises a skid-mounted panel of eight high-pressure filter units which may be operated at pressures up to 10,000 psi and circulation rates up to 34 BPM with a future upgrade to 15,000 psi. The operational parameters enable the unit to operate at high flow rates and the unit is suitable for deepwater applications. Eight filter units, aligned four on each side, house 8- or 12-gauge gravel-pack screens. The system is operated one side at a time to enable uninterrupted continuous filtration downstream of the rig triplex pumps in the event one side plugs. The HPDU can also be easily by-passed to enable for sand control pumping operations and viscous sweeps. This system was deployed and used in 60 different wells, primarily in the Gulf of Mexico. It has been in use since 2011 and the precursor system has been used since 2000 in 95 wells. The system can remove debris before entering the wellbore and captures damaging debris contained or dislodged in the tanks or transfer lines. In a case study, 5,286 bbls were pumped through one side and 4,329 bbls through the other side to capture 10.8 lbs and 9.2 lbs, respectively. The captured debris comprised predominantly iron-rich scale fragments, barite, calcite, sunflower seed hulls and bulk material. This paper presents the advantages of the HPDU in optimizing completion and workover operations by reducing downtime and preventing damaging material from affecting the downhole equipment operation. The HPDU acts as the final line of defense in downhole debris management, protecting downhole tools and equipment by keeping completion fluid free of damaging debris. Working in conjunction with diatomaceous earth (DE) and cartridge filtration, the system removes solids before they can enter the wellbore. Case histories of the deployment of the HPDU and the recovered debris are presented.