Publications

ELG-X was drilled from an existing platform, necessitating the wellpath to pass within close proximity of an adjacent well with an SF of 0.79. An SF below 1 poses a risk of collision due to overlapping Ellipsoid of Uncertainty (EOU), jeopardizing drilling and company's business plan. Hence, effective mitigation and directional planning were crucial for safe well execution.
A comprehensive strategy was crafted for effective risk mitigation, involving two key activities in the drilling process. Firstly, endorsing the use of a 12-1/4” pilot hole, typically employed for mitigating shallow gas risks, aimed to minimize top-hole interval hole contact. Engineering measures included GWD utilization, a high bend-degree mud motor, passive rock bit usage, subject and adjacent well monitoring, and well integrity placement. Secondly, the 17-1/2” hole enlargement process focused on maintaining drilling parameters and utilizing a less aggressive hole opener to safeguard against adjacent well damage.

Utilizing a 12-1/4” rock bit and a 1.83-degree bend mud motor, controlled drilling in the collision risk interval was conducted. Rigorous control parameters and survey monitoring revealed no major collision indications. ELG-X trajectory safely separated from the adjacent well, achieving an SF above 1. Positive signs persisted during the 17-1/2” hole enlargement, ensuring smooth upcoming operations like running 13-3/8” casing and cementing. In summary, the top-hole section is secure with no safety incidents or related NPT concerns.

This paper details the implementation of a collision mitigation strategy in the ELG-X well, Offshore North West Java Operation, serving as a valuable reference for future drilling. It showcases a successful case of top-hole drilling in a dense fixed platform with a minimum SF. The strategy is anticipated to provide insights for unlocking idle wells facing similar challenges as ELG-X.