In a deep gas wells drilling project, due to surface location limitations, predetermined target, and completion requirements, an S shape well profile is required. The well type is one of the most challenging due to the extended tangent section, increasing the risk of differential sticking, hole cleaning, extended reaming while tripping, and losses risk from the fracture-prone formation. An aggressive target at the outmost reservoir boundary is determined, requiring delivery of the furthest step-out S shape well, demanding more advanced technology and rigorous well planning.
Comprehensive well planning and strategy, utilizing cutting-edge technology to achieve the furthest step-out S shape well. –Thorough offset wells analysis, identifying best drilling practices for the most critical S shape directional section.–Modified S shape well design, dividing two directional sections to enable reaching desired reservoir target.–Latest generation of RSS technology with a more robust system and improved tool reliability, enabling the achievement of required DLS in high drilling dynamic conditions.–Optimized BHA design, improved drilling fluid design, and LCM strategy, enabling the achievement of maximum drilling parameters while minimizing differential sticking and losses risk.–Specific casing and light cementing design strategy in the extensive S shape section allowing the casing to reach the bottom smoothly and avoid losses risk while cementing due to higher ECD.
High drilling performance was achieved within the S shape well type in the field with no downhole tool failure nor drilling complexity and meeting desired well trajectory. High losses risk in the section and differential sticking was avoided, ensuring close adherence to drilling fluid parameters with bridge and seal strategy while drilling. The determined reservoir target was successfully reached with a total horizontal displacement of 3,140 ft (~1 km), resulting in the longest step-out S shape well in the deep gas well project.
No wiper trip was required prior to running casing following best drilling practices and drilling fluid design and strategy prior to POOH the BHA. The casing string was able to run smoothly in the field's longest open hole section, with less than maximum rig hoisting capacity, following low drag friction factor to the casing point. The cementing job was performed using a real-time top of cement identifier and was further performed successfully without inducing any losses using a light slurry strategy and met the objective to seal off the reservoir formation.
The novel holistic strategy encompasses cutting-edge technology utilization, Innovative well construction design, optimized BHA and drilling strategy, drilling fluid strategy, and specific measures in the casing and cementing design and execution, resulting in successfully delivering the longest step-out S Shape well in a deep gas drilling project. Collaboration from a team consisting of multi-technical expertise is also crucial to efficiently design and execute the work, leading to successful well delivery.
