Experience and Lessons Learned from the Jet-In and Drill-Ahead Operation During Malaysia Deepwater Drilling Operations

Surface casing jet-in and drill-ahead have become a common practice for deepwater drilling operation around the world. The main objective of the jet-in and drill-ahead operation is to set the surface conductor casing which is typically 36-inch in size and drill ahead the next hole section with the same bottomhole assembly (BHA). This paper reviewed 25 jet-in and drill-ahead BHA runs for deepwater drilling operations in Malaysia, with the intention to share the experience and findings. It is aimed to highlight the pertinent operating procedures needed for a successful jet-in and drill-ahead operation for future deepwater drilling operations, both in Malaysia and in other parts of the world. Multiple designs of BHAs in various sizes were imperative to achieve an optimum outcome for the jet-in and drill-ahead operation. The bit size, jet-in procedures, jetting speed, bit extension (stick out), assembly type, flow rate, formation and survey procedures are among other key aspects for a successful deepwater jet-in and drill-ahead operation. While all the deepwater jet-in and drill-ahead operations in Malaysia were performed with a mud motor BHA, a recent deployment of a rotary steerable system BHA in an ultra deepwater drilling operation had achieved a faster, verticality improvement to ±1°, a value-added outcome.