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Review
. 2020 Jun 23;6(6):e04065.
doi: 10.1016/j.heliyon.2020.e04065. eCollection 2020 Jun.

Design and capital cost optimisation of three-phase gravity separators

Tariq Ahmed  1 , Paul A Russell  2 , Nura Makwashi  1 , Faik Hamad  2 , Samantha Gooneratne  2
Affiliations
Review

Design and capital cost optimisation of three-phase gravity separators

Tariq Ahmed et al. Heliyon. .

Abstract

The separation of produced fluids is essential once it reaches the surface. This separation is achieved in gravity separators. The design and sizing of separators can be challenging due to the number of factors involved. Improper separator design can bottleneck and reduce the production of the entire facility. This paper describes the development of a capital cost optimisation model for sizing three phase separators. The developed model uses GRG Non-linear algorithms to determine the minimum cost associated with the construction of horizontal separators subject to four sets of constraints. A numerical sizing example was solved to provide the details associated with the model and the ease with which parameters can be varied to suit the user's needs. Finally, a spreadsheet comparison between results obtained from the developed model and four other extant models is carried out. Results indicated that the developed model predicted results within an absolute error of ±5m3 in most cases and a maximum of ±12.5m3 for very high gas flows in comparison to conventional models developed based on retention time theory.

Keywords: Capital cost; Chemical engineering; Mathematical modeling; Mathematical optimisation; Oil and gas; Organic chemistry; Petroleum engineering; Petroleum industry; Three phase separator.

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Figures

Figure 1
Figure 1
Process Flow Diagram for the current Model.
Figure 2
Figure 2
Separator Outlet Section showing outlet constraints. HHLL = High-high liquid level, HLL = High liquid level, NOL = Normal operating level, LLL = Low liquid level, LLLL = Low-low liquid level, HHIL = High-high interface level, HIL = High interface level, NIL = Normal interface level, LIL = Low interface level, LLIL = Low-low interface level, BV = Vessel bottom, TV = Vessel Top.
Figure 3
Figure 3
Cylinder partially filled with liquid.
Figure 4
Figure 4
Screenshots of input page for developed model.
Figure 5
Figure 5
Daily gas, oil and water production data.
Figure 6
Figure 6
Length and diameter against Oil Flow rate at Fixed Gas and Water Flows. Where [33] is Abdel Aal, Aggour and Fahim (2003) [4], Arnold and Stewart (2008) [7], is Svrcek and Monnery (1994) and [34] is William (2015).
Figure 7
Figure 7
A graph of volume against Flowrate at Fixed Gas and Water Flows.
Figure 8
Figure 8
A graph of Slenderness ratio against Oil Flow rate at Fixed Gas and Water Flows.
Figure 9
Figure 9
Diameter and Length against water flow rate at Fixed Gas and Oil Flows.
Figure 10
Figure 10
A graph of volume against Flowrate at Fixed Gas and Oil Flows.
Figure 11
Figure 11
Slenderness ratio against Water Flow rate at Fixed Gas and Oil Flows.
Figure 12
Figure 12
Diameter and Length against Gas Flow rate at Fixed Oil and Water Flows.
Figure 13
Figure 13
A graph of volume against Flowrate at Fixed Oil and Water Flows.
Figure 14
Figure 14
Slenderness Ratio against Gas Flow rate at Fixed Oil and Water Flows.
Figure 15
Figure 15
Diameter and Length against flowrates for high gas flowrates.
Figure 16
Figure 16
A graph of volume against Flowrate at Fixed Gas and Oil Flows.
Figure 17
Figure 17
Slenderness ratio for very high gas flows.
See this image and copyright information in PMC

References

    1. IEA. Organisation for Economic Co-operation and Development; OECD: 2017. World Energy Outlook 2017.
    1. Vileiniskis M., Remenyte-Prescott R., Rama D., Andrews J. Fault detection and diagnostics of a three-phase separator. J. Loss Prev. Process. Ind. 2016;41:215–230.
    1. Song J.H., Jeong B.E., Kim H.J., Gil S.S. Offshore Technology Conference. 2010. Three-phases separator sizing using drop size distribution.
    1. Arnold K., Stewart M. In: Chapter 5 - Three-phase Oil and Water Separation. Arnold ” K., Stewart M., editors. Gulf Professional Publishing; Burlington: 2008. pp. 244–315.
    1. Ghaffarkhah A., Shahrabi M.A., Moraveji M.K. 3D computational-fluid-dynamics modeling of horizontal three-phase separators: an approach for estimating the optimal dimensions. SPE Prod. Oper. 2018;33(04):879–895.

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