Improvement of Conductor Driving Operation for Deeper Penetration to Prevent Drive-Drill Operation: Cost-Effective and Efficient Conductor Installation in Offshore East Java, Indonesia

Abstract In December 2021, Husky-CNOOC Madura Limited (HCML) commenced the ten (10) wells development drilling campaign of three (3) fields (Field M1, Field M2, and Field M3) in the East Java Basin, Indonesia. This paper aims to elaborate the 20in conductor driving operations in the first two wells of Field M1. Various valuable lessons learned were established, including the drive-sub modification to improve driving performance that leads to the success of 20″ conductor driving operations in the subsequent five wells of Field M2. Multidisciplinary approach including geotechnical, drilling engineering, and marine structure projects worked collaboratively in evaluating the geotechnical survey data, assessing subsurface risk and hazard, selecting suitable driving equipment and conductor casing. The safe conductor setting depth area were determined based on the assessed axial-lateral loads and soil parameter, platform structure and piles depth, conductor drive-ability study and driving refusal, and subsurface formation layers. Conductor casing provides the structural integrity of the wellbore. This casing is crucial, as it will bear the static and dynamic load above and under the conductor casing and support the integrity for the subsequent drilling section by correctly setting the conductor depth. Based on actual operational data, proactive measures were taken to apply lessons learned from the driving operations of the first two wells to the subsequent well. During the planning phase for the next well, these lessons were further incorporated into equipment design improvements, including modifications to self-manufactured drive-subs according to hammer design specifications and operational requirements. This optimization aimed to reduce the need for the drive-drill option, enhancing operational efficiency, safety, and reducing complexity. By establishing the comprehensive conductor-driving plan, contingency plan, particularly the modification self-design of equipment, the conductor casing was successfully driven to the desired depth in subsequent five wells of Field M2 effectively. All these efforts resulted in approximately one-day operation time, which is equivalent to approximately USD 250,000 cost savings. The novelty of this paper is the comprehensive design and operational improvement of conductor driving operation. By having these design and operational improvements, HCML successfully managed to drive 20″ conductor deeper than section target depth, which lead to the operation time efficiency, since no drive-drill operation required. The lesson learned and optimization reported herein can be used as a reference for driving conductor operation, particularly in a similar area.