The Dual Gradient Drilling Lab is designed to help the industry better understand what will happen in the junction between the marine drilling riser and the subsea pump. The equipment is currently set up to model a deepwater dual gradient riser/subsea pump/return line system utilized in ultra-deepwater drilling.  We hope to determine how much gas entering the riser is diverted to the subsea pump and how much continues upward and accumulates at the top of the riser, and how we can maximize the gas that exits through the subsea pump.

Part of this study will develop procedures where the riser itself can be utilized in handling this gas from kicks.  This type of research will help future drilling operations recognize and avoid the dangerous pressure situations that led to the Macondo blowout, and possibly create safer equipment to further reduce risk.

The lab system consists of clear PVC pipe (six inches in diameter) to simulate the marine drilling riser, small diameter clear PVC inner pipe to simulate the drillstring and a six-inch outlet approximately six feet from the bottom of the “marine riser” to act as the outlet of the riser (inlet of the subsea pump).  There are two centrifugal pumps: one to act as the mud pump where they can pump straight up from the bottom of the riser or down the drillpipe and up the riser annulus, and one connected to the riser outlet to act as the subsea pump (either for the enhanced drilling EC Drill pump or the SMD Mudlift pump).  Finally there is an air compressor used to pump air into the bottom of the riser to simulate gas entering the system.  The clear pipe is mounted to a steel frame which can be lifted from horizontal to vertical by a winch attached to a beam in the building.  The lab can run experiments at any angle from horizontal to vertical. 

Videos from the experiments can be viewed here.