Abstract
Due to persistent clay swelling issues leading to borehole breakouts in Field BC, the operator opted to seek alternative solutions to mitigate risks of wellbore stability (WBS) issues. Conventional drilling with drill pipe and running casing separately exposes the open hole for a long time, in between (Bottom Hole Assembly) BHA tripping out to casing running. This in turn results in significant water absorption by shallow clay dominant formations leading to cavings and collapse. To resolve this issue, Directional Casing Drilling (DCD) technology was explored in order to drill and case the hole at the same time. DCD technology is an enabler for batch top hole section drilling optimization of Field BC in Malaysia to drill and secure every foot drilled to section target depth (TD) in a single run and through the restricted wellhead design.
With extensive studies to mitigate the risk and challenge, the DCD technology was successfully implemented in Field BC for five wells. Moreover, several others added benefit of DCD technology such as reduced personnel head count during the operation on the rig floor and improved rig safety throughout the operation by eliminating the manual pipe, minimal chemical consumption during DCD technology with seawater and hi-vis instead of Pump and Dump (PAD) mud or Synthetic Oil Based Mud (SOBM) helps reduce the impact on the sea habitat. Most importantly, with these benefits introduced by 13-3/8″ DCD technology, this drilling campaign has saved the operator 3 days with carbon emission reduction of 126 ton.