ESS Reverse Expansion: Solving a Bottle-Neck Problem

Abstract

The switch from gravel pack to expandable sand screen as the sand-face completion of choice for Chevron within its Joint Venture Offshore Operation in the Niger Delta region was performed due to significant amounts of non-productive time incurred while gravel-packing. These could be attributed to the required gravel pack equipment when compared to the space available on the rig as well as operational complexities. Therefore, the engineering and operations teams carried out studies on other feasible sandface completion options suitable for the reservoir sand control needs. An expandable sand screen completions type was risk assessed and qualified for use, and several wells have so far been completed using this lower / sandface completion method with great results.

Further optimizations were carried out in the planning and design phases to ensure flawless execution in terms of ensuring that the hole is open to screen deployment and expansion. The associated best practices and lessons learnt were implemented in the recent campaigns. However, during a recent execution, a different and new challenge was encountered. The expandable sand screens deployed, experienced some low to medium-level operational challenges which included the inability to run in hole to bottom and the inability to expand the screen to its total run depth. On that particular well, it was a combination of the aforementioned which resulted in significant operational challenges to pull the Axial Compliant Expander out of hole.

This technical paper sets out to describe the Expandable Sand Screens design philosophy, the efficiencies resulting from the improvement/optimization of the design, and the challenges experienced on "Well Z" with the action taken, which could be applied by any Operator if faced with similar obstacles.