GUIDE TO WORLD CRUDES: North Sea Schiehallion crude maintains steady quality

Built to replace the aging Schiehallion FPSO as part of the Quad 204 project in the west of Shetland region offshore UK, the new 270-m by 52-m Glen Lyon harsh-water FPSO is equipped to process up to 130,000 boe/d of heavy, low-sulfur Schiehallion crude. Production is exported via shuttle tanker to the Port of Rotterdam. Quad 204 is intended to redevelop and extend production from Schiehallion and Loyal fields to beyond 2035. Photo from BP PLC.

With seven new production system manifolds, overall subsea system capacity has been expanded beyond 75 wells. Equipped to store 800,000 bbl of oil, the new FPSO is connected to the seafloor via 21 new risers: 15 production, 3 gas, and 3 water injection. The 15 production risers are connected to production flowlines totaling 55 km in length. Gas risers and water injection risers are connected to existing infrastructure.

Designed to withstand winds in excess of 100 mph and waves that can reach more than 50 ft high, the FPSO is scheduled to ramp up to its plateau production rate of 130,000 boe/d by 2018.

The Glen Lyon FPSO is operated by BP with 36% interest alongside partners Royal Dutch Shell PLC 54% and Siccar Point Energy Ltd. 10%.

Schiehallion field interest is Shell 55%, BP 33%, and Siccar Point Energy 12%. Loyal field interest is split 50-50 between BP and Shell.

Schiehallion and the adjacent Loyal field have produced nearly 400 million bbl of oil since production started in 1998 (OGJ, Aug. 17, 1998, p. 38). The fields' redevelopment through the Quad 204 project targets recovery of an additional estimated 450 million bbl, extending their life beyond 2035.

Whole crude

API gravity at 60/60° F.: 25.2
Density at 15° C., kg/l.: 0.9025
Total sulfur, wt %: 0.458
Mercaptan sulfur, ppm (wt): 2
Total nitrogen, ppm (wt): 1,300.0
Basic nitrogen, ppm (wt): 418
Acidity, mg KOH/g: 0.310
Vis. at 20° C., cst: 67.41
Vis. at 30° C., cst: 38.55
Vis. at 40° C., cst: 23.96
Vis. at 50° C., cst: 15.930
Pour point, °C.: 6
Wax, wt %: 7.0
Carbon residue, wt %: 2.90
Asphaltenes, wt %: 0.30
Vanadium, ppm (wt): 8
Nickel, ppm (wt): 6
Iron, ppm (wt): 1
Ethane, wt %: 0.01
Propane, wt %: 0.02
Isobutane, wt %: 0.03
n-Butane, wt %: 0.06
Isopentane, wt %: 0.06
n-Pentane, wt %: 0.07
Cyclopentane, wt %: 0.02
C6 paraffins, wt %: 0.26
C₆ naphthenes, wt %: 0.33
Benzene, wt %: 0.01

Light naphtha, C5 to 95° C.

Yield on crude, wt %: 1.05
Yield on crude, vol %: 1.35
Density at 15° C., kg/l.: 0.7108
Total sulfur, wt %: 0.005
Mercaptan sulfur, ppm (wt): 12
Acidity, mg KOH/g: 0.030
Paraffins, wt %: 49.65
Naphthenes, wt %: 49.33
Aromatics, wt %: 1.02
n-Paraffins, wt %: 17.93
Research octane no.: 74.1

Heavy naphtha, 95-149° C.

Yield on crude, wt %: 2.55
Yield on crude, vol %: 3.00
Density at 15° C., kg/l.: 0.7743
Total sulfur, wt %: 0.006
Mercaptan sulfur, ppm (wt): 11
Total nitrogen, ppm (wt): 0.2
Acidity, mg KOH/g: 0.037
Paraffins, wt %: 21.63
Naphthenes, wt %: 67.18
Aromatics, wt %: 11.18
n-Paraffins, wt %: 3.17
Research octane no.: 72.0

149-175° C.

Yield on crude, wt %: 1.75
Yield on crude, vol %: 1.95
Density at 15° C., kg/l.: 0.8068
Total sulfur, wt %: 0.021
Mercaptan sulfur, ppm (wt): 23
Total nitrogen, ppm (wt): 0.5
Acidity, mg KOH/g: 0.037
Paraffins, wt %: 22.03
Naphthenes, wt %: 63.81
Aromatics, wt %: 14.15
n-Paraffins, wt %: 3.05
Research octane no.: -13.0

Kerosine, 175-232° C.

Yield on crude, wt %: 6.35
Yield on crude, vol %: 6.80
Density at 15° C., kg/l.: 0.8455
Total sulfur, wt %: 0.039
Mercaptan sulfur, ppm (wt): 5
Total nitrogen, ppm (wt): 1.1
Acidity, mg KOH/g: 0.029
Vis. at 40° C., cst: 1.40
Vis. at 60° C., cst: 1.081
Smoke point, mm: 17.5
Aromatics, vol %: 23.0
Naphthalenes, wt %: 1.28
Freezing point, °C.: -74.5
Cetane index (ASTM D4737-90): 29.2
Refractive index at 70° C.: 1.4438

Light gas oil, 232-342° C.

Yield on crude, wt %: 25.75
Yield on crude, vol %: 26.55
Density at 15° C., kg/l.: 0.8757
Total sulfur, wt %: 0.189
Mercaptan sulfur, ppm (wt): 3
Total nitrogen, ppm (wt): 21.0
Basic nitrogen, ppm (wt): 16
Acidity, mg KOH/g: 0.100
Vis. at 50° C., cst: 3.266
Vis. at 100° C., cst: 1.459
Aromatics, wt %: 33.60
Smoke point, mm: 13.4
Aromatics, vol %: 29.7
Naphthalenes, wt %: 9.81
Pour point, °C.: -21
Cloud point, °C.: -20
Freezing point, °C.: -17.0
Cetane index (ASTM D4737-90): 42.9
Refractive index at 70° C.: 1.4672
Wax, wt %: 1.4

Heavy gas oil, 342-369° C.

Yield on crude, wt %: 6.60
Yield on crude, vol %: 6.65
Density at 15° C., kg/l.: 0.8917
Total sulfur, wt %: 0.416
Total nitrogen, ppm (wt): 150.0
Basic nitrogen, ppm (wt): 60
Acidity, mg KOH/g: 0.250
Vis. at 50° C., cst: 8.312
Vis. at 100° C., cst: 2.744
Pour point, °C.: 9
Cloud point, °C.: 7
Cetane index (ASTM D4737-90): 55.0
Refractive index at 70° C.: 1.4774
Aniline point, °C.: 74.8
Wax, wt %: 9.8

Light vacuum gas oil, 369-509° C.

Yield on crude, wt %: 30.55
Yield on crude, vol %: 30.10
Density at 15° C., kg/l.: 0.9165
Total sulfur, wt %: 0.464
Total nitrogen, ppm (wt): 740.0
Basic nitrogen, ppm (wt): 235
Acidity, mg KOH/g: 0.410
Vis. at 60° C., cst: 24.920
Vis. at 100° C., cst: 7.445
Pour point, °C.: 27
Refractive index at 70° C.: 1.4867
Aniline point, °C.: 86.4
Wax, wt %: 10.0
Carbon residue, wt %: 0.04

Heavy vacuum gas oil, 509-550° C.

Yield on crude, wt %: 5.70
Yield on crude, vol %: 5.55
Density at 15° C., kg/l.: 0.9322
Total sulfur, wt %: 0.654
Total nitrogen, ppm (wt): 2,000.0
Basic nitrogen, ppm (wt): 570
Acidity, mg KOH/g: 0.600
Vis. at 60° C., cst: 140.000
Vis. at 100° C., cst: 25.740
Refractive index at 70° C.: 1.4994
Aniline point, °C.: 97.9
Wax, wt %: 13.1
Carbon residue, wt %: 1.10

550-585° C.

Yield on crude, wt %: 4.05
Yield on crude, vol %: 3.90
Density at 15° C., kg/l.: 0.9404
Total sulfur, wt %: 0.759
Total nitrogen, ppm (wt): 2,700.0
Basic nitrogen, ppm (wt): 775
Acidity, mg KOH/g: 0.590
Vis. at 60° C., cst: 301.700
Vis. at 100° C., cst: 44.670
Aniline point, °C.: 101.4
Wax, wt %: 14.9
Carbon residue, wt %: 2.76

Atmospheric residue, 369°-FBP

Yield on crude, wt %: 55.85
Yield on crude, vol %: 53.50
Density at 15° C., kg/l.: 0.9422
Total sulfur, wt %: 0.679
Total nitrogen, ppm (wt): 2,400.0
Basic nitrogen, ppm (wt): 733
Acidity, mg KOH/g: 0.400
Vis. at 60° C., cst: 129.900
Vis. at 100° C., cst: 25.240
Vis. at 120° C., cst: 14.24
Pour point, °C.: 30
Wax, wt %: 10.7
Carbon residue, wt %: 5.11
Asphaltenes, wt %: 0.55
Vanadium, ppm (wt): 15
Nickel, ppm (wt): 10
Iron, ppm (wt): 2

Vacuum residue, 509°-FBP

Yield on crude, wt %: 25.30
Yield on crude, vol %: 23.40
Density at 15° C., kg/l.: 0.9752
Total sulfur, wt %: 0.939
Total nitrogen, ppm (wt): 4,300.0
Basic nitrogen, ppm (wt): 1,333
Acidity, mg KOH/g: 0.390
Vis. at 100° C., cst: 224.800
Vis. at 120° C., cst: 96.29
Vis. at 150° C., cst: 36.06
Pour point, °C.: 36
Wax, wt %: 11.5
Carbon residue, wt %: 11.20
Asphaltenes, wt %: 1.20
Vanadium, ppm (wt): 33
Nickel, ppm (wt): 22
Iron, ppm (wt): 4

550°-FBP

Yield on crude, wt %: 19.55
Yield on crude, vol %: 17.85
Density at 15° C., kg/l.: 0.9885
Total sulfur, wt %: 1.020
Total nitrogen, ppm (wt): 5,000.0
Basic nitrogen, ppm (wt): 1,556
Acidity, mg KOH/g: 0.330
Vis. at 100° C., cst: 529.000
Vis. at 120° C., cst: 204.50
Vis. at 150° C., cst: 67.77
Pour point, °C.: 45
Wax, wt %: 11.1
Carbon residue, wt %: 14.20
Asphaltenes, wt %: 1.50
Vanadium, ppm (wt): 43
Nickel, ppm (wt): 28
Iron, ppm (wt): 6

585°-FBP

Yield on crude, wt %: 15.50
Yield on crude, vol %: 13.95
Density at 15° C., kg/l.: 1.0020
Total sulfur, wt %: 1.090
Total nitrogen, ppm (wt): 5,600.0
Basic nitrogen, ppm (wt): 1,761
Acidity, mg KOH/g: 0.260
Vis. at 100° C., cst: 747.600
Vis. at 120° C., cst: 281.10
Vis. at 150° C., cst: 89.76
Pour point, °C.: 54
Wax, wt %: 10.0
Carbon residue, wt %: 17.20
Asphaltenes, wt %: 1.90
Vanadium, ppm (wt): 53
Nickel, ppm (wt): 35
Iron, ppm (wt): 7