Abstract
Subsea separation refers to separating the production flow into its different phases (gas/liquid or liquid/liquid), mainly based on density differences between components, at the seabed.
The implementation of a subsea separation system allows for reduced back pressure on the subsea wellheads resulting to the increase of oil recovery and to the extension of production field lifetime while optimizing surface or onshore facilities.
Subsea Gas/Liquid separation allows to develop deepwater oil and gas fields with improved Flow Assurance philosophy while optimizing the overall production operability and fluid processing on topside.
As the industry needs to tackle challenges of deeper and higher-pressure fields, the subsea Gas/Liquid separation systems need to fulfil many requirements to allow for effective developments.
The paper focuses on Gas/Liquid separation providing a comparison of different separation technologies that could be applied subsea. A systematic approach is proposed to cover process performances, operational robustness, flexibility, and maintenance requirements.
An initial description of available technologies is presented. Gravity based separation vessels cyclones, including Gas Liquid Cylindrical Cyclone technology (GLCC) and inline cyclonic devices, and the subsea Vertical MultiPipe (VMP) are discussed.
The main parameters evaluated for each technology with respect to their potential subsea use is listed.
Also, to guide the assessment of separation technologies, a notional reference case, featuring typical specifications for a deepwater development, is proposed.
Based on the relevant parameters, especially identified for subsea applications, and reference case data, a ranking of technologies is presented. Moreover, a sensitivity allows to extend the considerations beyond the studied case showing where the various technologies are advantageous. Additionally, maturity and technology gaps for subsea applications is discussed.
Finally, the results show that, compared with the other technologies, the VMP provides a simpler and reliable design while providing a maintenance free solution.
The paper presents a thorough analysis of Gas/Liquid separation technologies applicable to subsea deepwater field development based on qualitative and quantitative results.
It gives an overview of advantages and limitations of each solution to support proper selection to any specific field.
