C3.1.0. Topside Intro 2020

1. Offshore Production Technology
Topside (Production) Systems
Marine & Offshore Technology

2. Learning Outcomes
1. Explain the functions and design considerations of the
processing facility
2. Understand the types of reservoirs, fundamental
organic chemistry, fluid types and product
specifications
3. Explain, with a diagram, the essential components and
processes on the topside of the FPSO

3. 1. Explain the functions and design
considerations of a processing facility

4. Functions of a Processing Facility
• Separate the reservoir fluids, oil, gas and water from each
other
• Treat the fluids as necessary
• Store fluids (dead crude and produced water) in tanks
• Export (dead crude) or dispose (produced water) of them
efficiently and safely
Key Knowledge

5. Design of a Processing Facility
Design of a processing facility requires:
• knowledge and understanding of the composition (organic
chemistry),
• physical properties of the reservoir fluids to be produced
(both on start-up and with time) and
• specification of the product to be produced.
Key Knowledge

6. 2. Understand the types of reservoirs,
fundamental organic chemistry, fluid types
and product specifications

7. Types of Reservoirs
1. Crude Oil Well:
The reservoir contains predominantly Black Oil (Crude) with
amounts of Associated Gas (Natural Gas and Condensate)
2. Dry Gas Well
The reservoir contains predominantly Raw Gas or non-associated
gas
3. Condensate Well
The reservoir contains Raw Gas and Gas Liquids (heavier alkanes)
Key Knowledge

8. Fundamental Organic Chemistry
• Oil & Gas fluids – fundamentally hydrocarbon (HC)
• Main constituents are from Alkanes (HC with single molecular
bonds)

9. Conversion Factors
Volume and Production rate
1 barrel = 0.1589873 m3
1 bpd = 0.0066239 m3/h
1,000,000 bpd = 6623.875 m3/h
1 scf/bbl = 0.178 (m3/m3) Gas to Oil ratio
1 bbl/mmcf = 5.61 (cm3/m3) Liquid to Gas ration
Heating value
1 btu/scf = 39.3807 kJ/Nm3

10. Relative Composition of Well Fluid Types
Mol %
Component Black Oil Volatile Oil Condensate Gas
Methane CH4 48.83 64.36 87.02 95.85
Ethane C2H6 2.75 7.52 4.15 2.67
Propane C3H8 1.93 4.74 2.20 0.34
Butane C4H10 1.60 4.12 1.70 0.52
Pentane C5H12 1.15 2.97 0.83 0.08
Hexane C6H14 1.59 1.38 0.60 0.12
Heptanes C7
+ 42.15 14.91 3.50 0.42
TOTAL 100.00 100.00 100.00 100.00

11. Properties of Well Fluid
Property Black Oil Volatile Oil Condensate Gas
Mol Wt of C7
+ 225 181 112 157
GOR
(SCF/BBL)
625 2,000 182,000 185,000
Liquids/Gas Ratio
(BBL/MMSCF)
1,600 500 55 95
Oil Gravity
(API)
34.3 50.1 60.8 54.7
Colour Black Brown Straw

12. Typical composition of Black Oil
from North Sea (example)
Mole %
Nitrogen 0.12
Carbon Dioxide 0.92
Methane 37.61
Ethane 8.22
Propane 6.13
Isobutane 1.05
N Butane 3.44
Iso Pentane 1.14
N-pentane 1.87
Hexane’s 2.42
Heptanes 4.42
Octanes 4.85
Nonances 3.65
Decanes 2.92
Undecanes+ 21.31
Total 100.00
Molecular Weight 106.3

13. Physical Properties of North Sea Black Oil
Arrival Pressure 12 bara
Arrival temperature max oil, no water 60C
Arrival temperature oil, max water 80C
Arrival temperature, minimum 50C
Wellhead flowing pressure 35 to 80 bara
Wellhead flowing temperature 70C to 90C
Wellhead shut in pressure 160 bara
Pour point range  15C to  12C
Cloud point Range 40C to 50C
Gas to Oil Ratio (GOR) Range 500 to 700 scf/bbl
API Gravity Range 35 to 38 @15C
Example

14. Typical Product Specifications
• Crude Oil Product Specification (on-loading)
• Associated Gas Export Specification
• Water Injection Specification
• Produced Water Specification
• Fuel Gas Specification

15. Typical Specification of (Dead) Crude Oil
Flow rate : 60,000 BOPD
Temperature : 50C minimum @ shuttle tanker
Pressure : 10 bara
TVP : 0.73 bara @ 38C (10.6 psia @ 100F)
RVP : 0.46 bara (6.7 psi)
BS&W : 0.5%
Salt Content : 1900 milligramme/litre (mg/l)
H2S Content : 1.0 ppm
Total sulphur : 0.3% wt
CO2 Content : 0.005 mole %

16. Typical Specification of Export Gas
Flowrate : 40 mmscfd (No fuel gas take off)
Gas Lift Flowrate : 5.0 mmscfd/well
Temperature : 51C
Pressure : 175 bara
Water dewpoint :  26C @ 76 bara
Hydrocarbon dewpoint :  1C @ 97 bara
H2S Content : < 1.0 ppm
CO2 Content : 1.7 mole %

17. Specification for Water Injection
Flowrate : 80,000 BWPD
Temperature : 10 to 30C
Pressure : 205 bara at FPSO
Pressure 201 bara at well
O2 concentration : 0.10 mg/I (without O2 Scavenger)
O2 concentration : 0.01 mg/I (with O2 Scavenger)
Solids content : 95% removal of  microns

18. Specification for Produced Water
Handling capacity : 70,000 BWPD
Discharge temperature range : 50 to 80C
Oil content : 40 ppm (free oil)

19. Specification of Fuel Gas
Flowrate (average) : 5 mmscfd
Temperature range : 50C to 80C
Pressure : 7.9 bara
MW range 27 to 29
Gross heating value : 1595 BTU/SCF
Net Heating value : 1456 BTU/SCF

20. 3. Explain, with a diagram, the essential
components and processes on the topside
of the FPSO

21. FPSO Layout

22. Oil & Gas Production Facilities
Production Facilities
• Oil Separation System
• Gas Compression System
• Water Injector System
• Produced Water System
Supporting Facilties
• Cooling Medium System
• Heating Medium System
• Fuel Gas System
• Flare and Vent System
• Diesel Fuel System
• Drains System
• Chemical Injection System
• Compressed Air System
• Inert Purge Gas System
• Fresh / Potable Water System
• Fire Water System
• VOC Recovery System

23. Primary Recovery
Key Diagram to draw

24. Essential Processes on the Topside
1. Three-phase Separation
a. To separate the reservoir fluids into 3 phases: oil, gas and water by
gravity. Residence time (time for settling) is typically 20 min.
2. Separate phase treatment for export, disposal, injection and
support production
a. Oil Phase: Dehydrated and Stored. Subsequently, exported via
shuttle tankers or subsea pipelines
b. Gas Phase: Compressed and Dehydrated for export, onboard
consumption, gas lift and gas injection (enhanced oil recovery -
EOR)
c. Water Phase: Treated and Disposed/Reinjected into wells for EOR
Key Explanation

25. Primary Recovery

26. http://tiny.cc/DEOPT_FPSO

28. Key Questions
1. Explain the (a) functions and (b) design considerations
of the processing facility
2. Explain the three types of oil & gas wells.
3. Explain, with a diagram, the essential components and
processes on the topside of the FPSO.

29. 4. Other Diagrams

30. FPSO Layout
http://tiny.cc/DEOPT_FPSO

31. Falcon FPSO - Layout

32. Main Processing Systems on FPS

33. Block Diagram of Systems Onboard

34. Schematic Layout of Processing Systems
FPSO Anasuria