Simulation-Based Optimization for Multi-Stage Crude Oil Production Units: Economic Evaluation and Decision-Making Process

Document Type : Research Paper


1 Department of Gas and Petroleum, Yasouj University, Gachsaran, Iran

2 Master of Chemical Engineering, National Iranian South Oil Company, Iran

3 The University of Saskatchewan, Department of Chemical and Biological Engineering Saskatoon, SK, Canada


The optimization of the operating pressure of the separators in the multistage crude oil production units has an undeniable effect on the quantity and quality of oil production. In this regard, the present study exploited a simulation-based approach to optimize a multistage crude oil production unit through determining the optimal separator pressure and number which maximizes the oil production rate, and operational flexibility while minimizing fixed and operating costs, and power consumption of the compressors. The decision-making process was performed for two cases in the National Iranian South Oil Company. The number of separation stages and their different arrangements were considered as the desired goals. According to the results, for the first case, maximum oil production can be achieved using these two-phase separators and one degasser tank, while the cold stripping method was recommended for the second case. Furthermore, economic evaluations were conducted by calculating the fixed initial investment and the total operating costs. The simulation results predicted the pressure of the production well in 2030 as 8.27 MPa. For the reservoir pressure of 7.58 MPa, the fixed project costs will be reduced by $11965307, while the oil production will decrease by about 20 barrels per day. It will result in a $58.4 million reduction in revenue over the next twenty years. Therefore, the optimal pressure of the reservoir was assumed to be about 6.89 MPa.


  1. Cho Y, Kwon S, Hwang S. A new approach to developing a conceptual topside process design for an offshore platform. Korean Journal of Chemical Engineering. 2018; 35(1):20-33.
  2. Kim IH, Dan S, Kim H, Rim HR, Lee JM, Yoon ES. Simulation-based optimization of multi-stage separation process in offshore oil and gas production facilities. Industrial & Engineering Chemistry Research. 2014;53(21):8810-20.
  3. Liu Y, Wang C, Cai J, Lu H, Huang L, Yang Q. Pilot application of a novel Gas–Liquid separator on offshore platforms. Journal of Petroleum Science and Engineering. 2019;180:240-5.
  4. Li H, Chen J, Wang J, Gong J, Yu B. An improved design method for compact vertical separator combined with the theoretical method and numerical simulation. Journal of Petroleum Science and Engineering. 2019;173:758-69.
  5. Ghaedi M, Ebrahimi AN, Pishvaie MR. Application of genetic algorithm for optimization of separator pressures in multi-stage production units. Chemical Engineering Communications. 2014;201(7):926-38.
  6. Sarvestani AD, Goodarzi AM, Hadipour A. Integrated asset management: a case study of technical and economic optimization of surface and well facilities. Petroleum Science. 2019;16(5):1221-36.
  7. Andreasen A. Applied Process Simulation-Driven Oil and Gas Separation Plant Optimization using Surrogate Modeling and Evolutionary Algorithms. ChemEngineering. 2020; 4(1):11.
  8. Le TT, Ngo SI, Lim Y-I, Park C-K, Lee B-D, Kim B-G, et al. Three-phase Eulerian computational fluid dynamics of air–water–oil separator under off-shore operation. Journal of Petroleum Science and Engineering. 2018;171:731-47.
  9. Povarchuk D, Humeniuk T, Lazoriv N. M. Gorbiychuk. Eastern-European Journal of Enterprise Technologies. 2018;1(2):91.
  10. AL-Maliki MAS. An investigation of the optimum separation conditions in the Degassing stations of one of southern Iraqi oil Field. Journal of Petroleum Research & Studies. 2019(23):E22-E41.
  11. Bahadori A, Vuthaluru HB, Mokhatab S. Optimizing separator pressures in the multi-stage crude oil production unit. Asia‚ÄźPacific Journal of Chemical Engineering. 2008;3(4):380-6.
  12. Andreasen A, Rasmussen KR, Mandø M. Plant Wide Oil and Gas Separation Plant Optimisation using Response Surface Methodology. IFAC-PapersOnLine. 2018; 51(8):178-84.
  13. Shishkin N, Maksimenko YA. Improvement of Designs of Oil and Gas Separators for Offshore Oil Production Platforms. Chemical and Petroleum Engineering. 2020:1-6.
  14. Al-Mhanna NM. Simulation of High Pressure Separator Used in Crude Oil Processing. Processes. 2018; 6 (11):219.
  15. Bakyani AE, Heidari S, Rasti A, Namdarpoor A. Development an Easy-to-Use Simulator to Thermodynamic Design of Gas Condensate Reservoir’s Separators. Modeling and Numerical Simulation of Material Science. 2018; 8(1):1-19.
  16. Okafor E, Kalagbor C, editors. Crude Oil and Associated Production Optimization: A Case Study of X Field in Nigeria's Niger Delta Region. SPE Nigeria Annual International Conference and Exhibition; 2017: Society of Petroleum Engineers.
  17. Motie M, Moein P, Moghadasi R, Hadipour A, editors. Separator Pressure Optimisation and Cost Evaluation of a Multi-stage Production Unit Using Genetic Algorithm. International Petroleum Technology Conference; 2019: International Petroleum Technology Conference.
  18. Mahmoud M, Tariq Z, Kamal MS, Al-Naser M. Intelligent prediction of optimum separation parameters in the multi-stage crude oil production facilities. Journal of Petroleum Exploration and Production Technology. 2019;9(4):2979-95.
  19. Bayoumy SH, El-Marsafy SM, Ahmed TS. Optimization of a saturated gas plant: Meticulous simulation-based optimization–A case study. Journal of Advanced Research. 2020;22:21-33.
  20. Lavenson DM, Kelkar AV, Daniel AB, Mohammad SA, Kouba G, Aichele CP. Gas evolution rates–A critical uncertainty in challenged gas-liquid separations. Journal of Petroleum Science and Engineering. 2016;147:816-28.
  21. Al-Jawad MS, Hassan OF, editors. Optimum separation pressure for heavy oils sequential separation. Abu Dhabi International Petroleum Exhibition and Conference; 2010: Society of Petroleum Engineers.
  22. Gallo WL, Gallego AG, Acevedo VL, Dias R, Ortiz HY, Valente BA. Exergy analysis of the compression systems and its prime movers for a FPSO unit. Journal of Natural Gas Science and Engineering. 2017;44:287-98.
  23. Helmy T, Hossain MI, Adbulraheem A, Rahman S, Hassan MR, Khoukhi A, et al. Prediction of non-hydrocarbon gas components in separator by using hybrid computational intelligence models. Neural Computing and Applications. 2017;28(4):635-49.
Volume 56, Issue 1
June 2022
Pages 53-75
  • Receive Date: 14 October 2021
  • Revise Date: 09 January 2022
  • Accept Date: 10 January 2022
  • First Publish Date: 15 January 2022