Case Study: Remote Monitoring of a Solids-Management System in the UKCS
Authors: Heradstveit Øyvind 
Published: April 2023

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A well in the Southern North Sea was shut in due to clay and proppant production. Before it was shut in, it had been producing 1,199 B/D. The challenge presented by the operator was to clean out the well and reestablish production. The operator wanted to boost sustainability metrics and reduce emissions as much as possible.
Adding further complexity to the project, the platform in use was a normally unmanned installation (NUI). This type of platform meant no crew could stay overnight and resulted in several new challenges being considered upfront.
1. Remote monitoring abilities were crucial.
2. A reliable, accurate information flow was key for planning workflow during the day.
3. The work window was reduced to 12 hours per day, so maintenance and the emptying of solids had to be carried out during the day.
4. Limited crane capacity was available for the rig-up and assembly.
The above considerations, coupled with the ability to remove personnel on board (POB), the efficiency of solids handling, and compact footprint, meant the DualFlow 5K PSI desander was selected as the equipment of choice by the operator.

Advance Planning
A 7-week wellbore cleanup was planned to reinstate production while also removing the clay/proppant solids. During this time, the FourPhase team also monitored the well performance.
Understanding the space constraints offshore was key. To kick off the project, a feasibility report was developed to capture basic well data, which included flow rates, oil/gas properties, pressure, temperature, expected solids production, and expected erosional rates. A site visit was arranged to identify laydown areas, pipework routing, connections, utilities, and rig-up possibilities. Simulations were also carried out to assess the flow and erosional performance and to ensure the planned work was within the operational window of the desander. By creating a 3D rig-up simulation in advance, it was determined that an efficient rig-up could be achieved. This stage also created logistical efficiencies, as accurate measurements for equipment and piping ensured that minimum excess material was shipped offshore. This approach further boosted the ESG metrics of the projects.

Implementation
The desander contains two patented, single-liner cyclones in one unit. As one vessel is isolated and flushed, production continues through the other, delivering a proven separation efficiency of 99.8% and a dynamic range of 20-μm to 10-mm solids up to 20,000 B/D and 20 MMscf/D. The result is continuous production and better asset management because the data allow early stages of erosion to be managed. Due to its design, it was uniquely able to tackle the specific challenges posed by this project.
The system was monitored by the operator’s nearby control platform, where the well could be shut in if there was an emergency. The Operations and Technology Centre in Bergen, along with the FourPhase Aberdeen facilities, remotely monitored the system’s key operating parameters.
From a POB perspective, the solution removed traditionally labor-intensive manual operations such as valve manipulation and flushing operations. These operations were run automatically or with a click of a button remotely. Removal of such operations directly reduced POB and associated emissions.