Crude oil - composition and processing

Transcription

1 Crude oil - composition and processing Tiina Komulainen Based on Morten Holmager (2010), Offshore book an introduction to the offshore industry, Offshore center Danmark.

2 Contents What is crude oil? Parameters Crude oil API-density sulfur content GOR WOR Design of oil separation (topsides) process HSE

3 What is oil? Reservoir: mixture of Gas components Oil components (light, heavy) Water Sand Separation from multi-phase mixture to crude oil (mixture of mainly oil components) Refining From crude oil to products like gasoline Source:

4 CRUDE OIL What is crude oil? Multi-phase flow from reservoir typically a mixture of: gas (C 1 C 4 ) light oil /naptha (C 5 C 9 ) paraffin oil (C 10 C 16 ) diesel oils (C 14 C 20 ) heavier oils(c 20 C 70 ) asphaltene, bitume (C 70+ ) sulphur water sand Some important properties of oil components Density ρ [kg/m 3 ] Viscosity μ [kg/ms], [cp] Molecular weight M [g/mol] Critical temperature T C [K] Critical pressure P C [Pa] Interaction with other components a i [-]

5 What is crude oil? Mixture of hundreds of oil compounds Reservoir multi-phase flow -> separation & stabilization - > crude oil, produced water, gas (,sand) Crude oil -> refinery -> products TRANSPORT TO REFINERY

6 What is oil crude oil separation Separation of multi-phase fluid (emulsion) of oil, gas, water and sand Three-phase separator with different internal equipment Typically requires multi-stage separation for acceptable crude oil quality Does not gasify under export conditions (T,P) Low water content No sand

7 Crude oil density: API gravity Density of separated oil, «crude oil» American Petroleum Institute (API) Density of crude oil ºC) compared to density of water (~1000kg/m 3 ) light crude: API >32 medium crude 22<API<32 heavy crude: API<22 API spg crude,60 F H O,60 F Source:

8 Crude oil sulfur content High temperature at refinery -> sulfur components form sulfur dioxide (SO 2 ) -> exhaust gas -> acid rain (H 2 SO 4 ) Sweet crude (Sulfur <0.5%) Sour crude (Sulfur> 0.5%) Examples Brent Blend is a light, sweet North Sea crude with a sulfur content of approximately 0.4% Russian Export Blend is a medium, sour crude oil with a sulfur content of approximately 1.2% Source:

9 Exercise 1 light/heavy, sweet/sour? Crude source Nigeria n-1 Paraffins vol% Aromatics vol% Naphtenes wt% Sulfur % API , Saudi Saudi , Venezu ela-1 Venezu ela 2 USA- Mid. USA, Texas North Sea- Brent , , , , , Naphta yield Source: Offshore book, 2010, p.9

10 Crude oil quality: impact on refining The quality of crude oil => level of processing and conversion for optimal mix of products Light, sweet crude is more expensive than heavier, sourer crude requires less processing More value-added products, such as gasoline, diesel, and aviation fuel. Heavier, sourer crude Additional pumping & diluting costs Lower percentage value-added products with simple distillation Requires additional processing (=requires more energy) to produce lighter products. Source: Offshore book

11 Petroleum production - separation Gas/oil/condensate/water separation High to low pressure Many process units oil separation (gravity separator) and treatment water treatment gas compression Products Stabilized crude oil (to refinery) Gas Condensate (Prod. water, sand) Sources:

12 Separation train - design Oil composion Heavy components hard to separate Emulsion with water Gas entrainment Reservoir pressure & temperature GOR and WOR developement over the life time of the field Gas to Oil Ratio increases Water to Oil ratio increases

13 Separation train - design Separation of components between gas and liquid: vapor liquid equilibrium (VLE) Component properties Surface between V-L Separation of liquid components between oil and water phase: gravitation Settling time -> separator length

14 Separation train - design K i Vapor-liquid equilibrium p k c, i p Temperature, pressure Properties of the components Simple calculation: Sandler s equation tot y i i k i 1 7,534 7,224 2,598ln T T L F x Fi 1 1 K i ci N i1 y i 1 T T ci Some important properties of oil components Density ρ [kg/m 3 ] Viscosity μ [kg/ms], [cp] Molecular weight M [g/mol] Critical temperature T C [K] Critical pressure P C [Pa] Interaction with other components a i [-]

15 Separation train - design Settling time Geometry of the separator Density of the different components -> gravity Breaking of the emulsion (water-sand-oil) Some important properties of oil components Density ρ [kg/m 3 ] Viscosity μ [kg/ms], [cp] Molecular weight M [g/mol] Critical temperature T C [K] Critical pressure P C [Pa] Interaction with other components a i [-]

16 Separation train - design Number of separation stages Desired crude oil composition Inlet pressure, temperature Typically 3 stages High Pressure ( atm) Medium/ Intermediate Pressure Low Pressure (1-10 atm) (coalescer 1atm) Goal: Maximal amount of stabilized crude oil Minimal amount of water and gas Condensate from scrubbers

17 Petroleum production - refining Crude oil processing at an oil refinery Distillation, cracking, separation, Energy consumption! Amount of products Depends on the crude quality and processing options available Source:

18 What is oil gasoline? Crude oil processed at a refinery => various products Most valuable products: Gasoline, diesel, kerosene Gasoline is a blend of alkanes. Mainly C 5 -C 10 Single bindings between C-atoms Name (C n H 2n+2 ) Methane CH 4 Ethane C 2 H 6 Propane C 3 H 8 Butane C 4 H 10 Pentane C 5 H 12 Heksane C 6 H 14 Heptane C 7 H 16 Octane C 8 H 18 Nonane C 9 H 20 Decane C 10 H 22 Formula C n H 2n+2 18

19 Exercise 2 separation of crude oil Why reservoir fluid needs to be processed before refining? Which factors determine the sizing of the separator? Which factors determine price of the crude oil (compared to Brent) Presentasjonens tittel

20 Petroleum production - HSE Sustainable development responsible energy production environmental protection Health Safety Environment Regulations ISO API (USA) Norsok (Norway) Source: blog.cifor.org/

21 Petroleum production - health Crude oil Mixture of over 200 different hydrocarbon compounds Extremely flammable Toxic, carsinogenic Major damage to health & environment Work environment safety precautions gloves, safety glasses, jacket, laboratory fume hood, explosion proof equipment, avoid heat, sparks, open flames tightly closed container, ventilated area Source:

22 Petroleum production safety Temperature, pressure at different parts of the production chain Quality of materials, safety and automation system, operators, all employees, local communities (pipelines, transport) Danger of explosion Material damages Case examples drilling rigs, refineries, etc

23 Petroleum production - environment Preserving the environment By improve air quality (flaring) preserve water resources (spills) protect biodiversity responsible waste management prevention and manage of accidental pollution Improving energy efficiency Development of renewable energy sources Source:

24 Petroleum production HSE What kind of experiences on HSE policies do you have? Why Health Safety and Environmental requirements are important in petroleum production plants? How can HSE awareness be improved by education / internal courses?

25 Oil producers Verdens største oljeprodusenter 2012 (kilde: Forbes): 1. Saudi Aramco - 12,5 Mbpd 2. Gazprom (Russia) 9,7- Mbpd 3. National Iranian Oil Co Mbpd 4. ExxonMobil Mbpd 5. PetroChina Mbpd 6. British Petroleum - 4.1Mbpd 7. Royal Dutch Shell - 3.9Mbpd 8. Pemex (Mexico) - 3.6Mbpd 9. Chevron - 3.5Mbpd 10. Kuwait Petroleum Corp Mbpd 11. Abu Dhabi National Oil Co Mbpd 12. Sonatrach (Algeria) - 2.7Mbpd 13. Total (France) - 2.7Mbpd 14. Petrobras (Brazil) - 2.6Mbpd 15. Rosneft (Russia) - 2.6Mbpd 16. Iraqi Oil Ministry - 2.3Mbpd 17. Qatar Petroleum - 2.3Mbpd 18. Lukoil (Russia) - 2.2Mbpd 19. Eni (Italy) - 2.2Mbpd 20. Statoil - 2.1Mbpd 21. ConocoPhillips 2.0Mbpd 22. Petroleos de Venezuela - 1.9Mbpd 23. Sinopec (China)- 1.6Mbpd 24. Nigerian National Petroleum - 1.4Mbpd 25. Petronas (Malaysia) - 1.4Mbpd

26 Petroleum production Landbased petroleum exploration and refining: ch?v=8w8sw98-sxq Production in Texas ch?v=9py8-xy9mko Subsea production: ch?v=apugpnu-pc0 Ormen Lange (gas production): ch?v=gz45mp7trmu&list=pl 3D2FA93D808614CC&index =1 Source: