AN AMBITIOUS exploratory well project has entered the record books – with AGR’s Riserless Mud Recovery (RMR™) system from their Enhanced Drilling Solutions division helping to make it possible.
Woodside called a total section depth of 1,905m (6,250ft) on the Tidepole East-1 exploration well off Western Australia. It was the first time that Woodside had used the Casing While Drilling (CWD) method on one of its wells and the depth reached sets a new world record for the technique.
RMR™ (example attached) enabled Woodside to use the type of drilling mud needed to maximize the wellbore smearing effect that CWD provides, which helps keep the wellbore stable.
The system allows top-holes to be drilled using weighted mud, with fluid and cuttings returned to the rig and no discharge. It is also able to supply the low pump rates and good hole-cleaning capability required to drill efficiently, despite the relatively narrow annulus that was a feature of this project.
Thanks to RMR™ and the casing being run during the drilling process, there were no losses to the formation during that stage – an all-too-common occurrence with conventional drilling method.
AGR’s ingenuity solves the challenge
Standard internal or external wellhead adapters could not be used on this project for the RMR’s™ Suction Module (SMO) without extensive modification to the Permanent Guide Base, or without causing difficulties when it came to landing the High Pressure Well Head (HPWH) on the Low Pressure Well Head (LPWH) later on in the operation.
AGR’s ingenuity provided the solution, with an internal adapter being devised that could be split. This meant that the casing could be drilled down with the SMO in place.
General Manager EDS Asia Pacific, Bernt Eikemo, said: “When it was time for the HPWH to be landed on the LPWH, the SMO could simply be lifted off the LPWH using two ‘tugger’ winches on the rig, with an ROV performing the split.
“This of course has never been done before but, with a simple design and good communication with the ROV company, it proved to be a great solution and it took next to no time for the ROV to release the locking pins and split the adapter.”
The operation went smoothly, with an impressive Rate Of Penetration (ROP) achieved of some 60m (197ft) per hour. Bernt added: “This would have been impressive even with conventional drilling. To be able to drill these kinds of wells and others in a quick, simple way like this can potentially create great savings for operators.
“Working within areas with challenging geotechnical conditions, a proper mud system and the ability to have full returns are vital for success. RMR™ is perfect for this application.”