On the basis of previous displacement operations in the Cygnus field, M-I SWACO prepared a detailed pit management program. Spacers were prepared in advance, and the wellbore cleanout string was run in the hole. A concentration of 10.8-lbm/galUS [1,296-kg/m3] VERSAPRO invert-emulsion reservoir drill-in fluid system was circulated and conditioned.
The pill train consisted of
- 50-bbl [8-m3] base oil followed by a 60-bbl [9.6-m3] high-viscosity push pill containing 5% SAFE-SURF EU agent
- 75-bbl [12-m3] wash pill containing 10% SAFE-SURF EU agent by volume
- 50-bbl [8-m3] high-viscosity catch pill containing 5% SAFE-SURF EU agent by volume ahead of 11-lbm/galUS [1,320-kg/m3] calcium chloride brine.
The chemicals were placed directly in the pits and blended by agitators in the pits. No foaming was observed after adding the chemicals.
The pill train was pumped at 3 bbl/min [0.48 m3/min] down the 5-in drillpipe and 2 3/8-in washpipe to the no-go landing nipple located at 12,374-ft [3,772-m] MD. Once all of the pills were 500-ft [152-m] MD above the MFCT multifunction circulating tool technology, the tool was opened, and the flow was increased to 14 bbl/min [2.2 m3/min].
