A common tool used for coiled-tubing support, a 100-bbl open-top tank can be handy in completion operations on a semi-submersible drilling rig to handle fluids returning during reverse circulation after tubing-conveyed perforating (TCP) runs, or after a frac pack. A 2-inch Coflexip hose directs fluid from the choke manifold on the rig floor to the pipe deck. A simple gas-buster separates gas from the liquid stream. Gas is vented roughly 25-feet above the deck. Gas-free fluid passes through two adjustable weirs where solids and liquid hydrocarbons (oil or condensate) can be trapped for transfer to cuttings boxes and onshore disposal. Clean fluid is pumped back to the pit room. -- The use of open-top tanks allows the crew to keep hydrocarbons out the pit room - containing the mess to a relatively small tank section that is much easier and faster to clean. When returns are free of hydrocarbons and solids, the crew can bypass the tank and go directly back to the pits.
