Sand Management Practices at a Mature Field in the Deepwater Niger Delta

Abstract

Abstract Field X is a field in the Niger Delta, located at a water depth of 4,800 ft. The field development strategy includes peripheral water injection and crestal gas injection with mid-flank oil production from multiple stacked reservoirs. All of the wells (injectors and producers) are subsea wells, tied back to a Floating, Production, Storage, and Offloading (FPSO) vessel via subsea flowlines. The production wells were completed with Frac-Packs for sand control and Intelligent Well Completion (IWC) systems to provide zonal information and control for effective simultaneous production of multiple zones per well. Several years after the start of production at Field X, failure of the Frac-pack sand control equipment were observed on several wells, resulting in sand production. This change in operating conditions was of significant concern because the Basis of Design (BOD) for the field hinged on sand-free production. Sand production could negatively impact the asset integrity of the field by increasing erosion on subsurface, subsea, and topsides equipment, causing damage to topsides production and water injection equipment, and causing process upsets from sand build-up in process vessels. In response to this new condition, a cross-functional team was assembled to review the root causes of the sand control failure, recommend operational changes to prevent future sand control failures, recommend options to mitigate the impacts of sand production to the field infrastructure and process systems, recommend strategies for performing surveillance of equipment to assure asset integrity, and maximize the value of the asset within the context of the new paradigm created by the failed sand control. This paper will highlight the strategies and methodologies adopted to manage sand production at Field X, which include maintaining production from wells with failed sand control at curtailed rates to achieve sand free production, preventing additional completion failures through enhanced flux modeling and by proactively performing acid stimulations to reduce velocities and erosion through the completions and help preserve completion integrity, and maintaining subsea and surface facilities integrity and operability through increased surveillance and solids management programs. These mitigation measures have helped to maintain production and minimize negative impacts to field EUR while maintaining asset integrity and operability.