Woodside Petroleum recently reached a total section depth of 6,250 ft on the Tidepole East-1 exploration well offshore Western Australia with the help of AGR’s riserless mud recovery (RMR) technology.
It was the first time that Woodside had used the casing while drilling (CWD) method on one of its wells, and the company believes the depth reached sets a world record for the technique. RMR 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 with 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. There were no losses to the formation during that stage.
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 wellhead on the low-pressure wellhead later in the operation.
AGR provided a solution involving an internal adapter being devised that could be split. This meant that the casing could be drilled down with the SMO in place.
The operation went smoothly, achieving a rate of penetration of approximately 197 ft/hr.
“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,” said Bernt Eikemo, general manager of AGR’s Enhanced Drilling Solutions division in the Asia Pacific.
RMR is a trademark of AGR.