Debottlenecking Approach Revitalizes Aging Platform by Increasing Production 30%
Authors: Carpenter Chris 
Published: October 2021

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203321, “Integrated Debottlenecking Approach Revitalizes Aging Platform by Increasing Production 30% in Gulf of Mexico,” by Ankur Gandhi, Sara L. McConkey, and Jeremy Kimbrough, SPE, Occidental, et al., prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed.
Successful identification, evaluation, and management of bottlenecks in a complex offshore production processing system is challenging but can increase daily production significantly. The Constitution platform in the Green Canyon area of the Gulf of Mexico, which was commissioned in 2006 with a nameplate capacity of 70,000 BOPD, is a complex system with four fields in varying stages of development. The complete paper focuses on a multidisciplinary process developed to identify, evaluate, and eliminate interdependent bottlenecks on the platform and its flowline network during a 16-month period; this synopsis details some of these findings.

Integrated Process
A study and field trial during 2016–17 demonstrated the ability to separate fluids above the design capacity, but the team faced challenges in terms of flow reliability even at lower production rates. Therefore, in 2017, an effort was launched to understand and mitigate this issue. The underlying process used for the effort stemmed from principles of Six Sigma and Gemba walks. The steps of the process, detailed in the complete paper, are as follows:
1. Define
2. Measure and analyze
3. Design
4. Verify and execute
5. Review
The process allows the team to see the variance between perception and reality. The results-driven, continuous-improvement approach also increases visibility among leaders, giving them a chance to interact with subject-matter experts (SMEs) and to understand key bottlenecks.

Platform Bottlenecks and Responses
Reservoir and Subsea Network Deliverability. The rate uplift from the debottlenecking efforts was estimated using a reservoir simulation model that included a fully integrated subsea flow net-work model, which solved the reservoir and flow network equations in the same Newtonian iteration. This type of simulation model particularly is suited for the problem at hand, provided that the reservoir model adequately matches historical well performance and the network model matches historical friction pressure losses as a function of rate. The simulation model predicted that the reservoir should be able to deliver a rate uplift of 30% above the production rate before debottlenecking.
Topsides Fluids Processing Debottlenecking: General. The late-life debottlenecking of the platform posed many process engineering challenges, some of which stemmed from the inherent flexibility for which the platform was designed. The multitude of gas paths available led to many viable operating alignments of sources to separators and then separators to compressor stages. One initial exercise for debottlenecking was to develop a matrix of potential future operating modes, which would account for the required operator flexibility, as well as to address compressor downtime and the resulting temporary rerouting of sources. Once this matrix was developed, topsides process simulations were developed for each to identify capacity requirements for each equipment item.
As detailed in the complete paper, topsides fluids processes involving the oil-cooling system and oil-system hydraulics were also debottlenecked.