Adopting Subsea Separation Technologies for Deepwater West-Africa: A Review Study

Recent developments in offshore oil and gas production indicate a trend of deployment of subsea separation technologies in a reasonable number of offshore oil and gas fields in the Northsea and Offshore Brazil. Although Pazflor field Offshore Angola has adopted a vertical gravity separator, there is still a slow acceptance of this technology in Offshore West-Africa. This work reviewed over ten technical papers and also captured expert views; identifying some of the challenges and potential benefits of subsea separation technologies to deepwater West-Africa. Subsea separation of gas and liquid phase for instance creates the opportunity to overcome hydrostatic pressure in lifting the produced fluid to the topside Floating Production Storage and Offloading (FPSO) vessel using single phase or hybrid pumps. Gas/liquid phase separation could also reduce possibility of flow assurance challenges like hydrates formation and slugging. In spite of these potential advantages, there are also challenges facing the deployment of subsea separation, especillay in West Africa oil fields. This work reviewed current trends, opportunities, challenges and best practices with respect to subsea separation. Also, possibility of a future driven by compact separators in deepwater environments was explored in this work. Strengths, weakness, opportunities and threats (SWOT) analysis was conducted to identify the key technical challenges and opportunities of already deployed subsea separation technologies in Pazflor and Shell BC 10 field. Improved phase separation was identified as one of the key benefits of compact separators. The challenges in accessing installation vessels for deployment of gravity based subsea separators in West-Africa was also highlighted as one of the key technical challenge in the deployment of subsea separators in Offshore West-Africa. Recommendations for future subsea separation technologies application in Deepwater West-Africa was also done in this work.