BP Oil International Ltd., a subsidiary of BP PLC, published an updated assay for Skarv Blend crude oil based on a sample taken Dec. 17, 2020 (OGJ, Jan. 2, 2017, p. 58).
BP Norge AS began production from Skarv oil and gas field on Dec. 31, 2012, from four reservoirs (Skarv A, BC, Idun, and Tilje) in 350-450 m of water on the Norwegian Continental Shelf, 210 km off Sandnessjoen, Norway, between Norne field, 35 km to the north, and Heidrun, 45 km to the south (OGJ Online, Jan. 4, 2013).
The development includes a 295-m long, 51-m wide floating production, storage, and offloading (FPSO) vessel that produces medium 52.0° gravity, low-sulfur (0.056 wt %) oil and condensate as well as rich gas from 18 operating production and injection wells drilled through five subsea templates.
With an oil storage capacity of 875,000 bbl and oil and gas production capacities of 85,000 b/d and 22 million cu m/day, respectively, the Skarv FPSO in 2020 produced 21 million boe, including 810,000 cu m of oil, 3.24 million cu m of gas, and 710,000 cu m of NGLs.
Skarv had an estimated ultimate recovery of around 111 million cu m of oil equivalent—including 25.2 million cu m of oil, 70.6 million cu m of gas, and 15.2 million of NGLs—upon its discovery in 1998, according to the Norwegian Petroleum Directorate. By yearend 2020, estimated remaining reserves stood at 8.8 million cu m of oil, 41.8 million cu m of gas, and 8.9 million cu m of NGLs.
The revised Skarv assay follows Aker BP’s late-2020 start of production from Ærfugl gas and condensate field development just west of Skarv field in 350-450 m of water. Tied to Skarv FPSO, the first phase of the two-phased Ærfugl development—which came on stream in November 2020—includes three wells, to be followed another three wells upon startup of Phase 2 in late 2021, all producing from Ærfugl gas reservoir. Ærfugl, at more than 60 km long and 2-3 km wide—holds about 300 million producible boe in Lysing formation sandstone of Cretaceous age at a depth of 2,800 m (OGJ Online, Nov. 13, 2020; Apr. 22, 2020). Alongside lowering Skarv FPSO’s carbon dioxide emissions by 30-40%, Aker BP said it expects Ærfugl Phases 1 and 2 will return Skarv to a plateau production of more than 170,000 b/d.
Aker BP ASA, which took ownership of BP Norge on Dec. 1, 2016, operates and holds a 23.8350% interest in Skarv and Ærfugl. Other interests in the two fields are held by Equinor Energy AS (36.1650%), Wintershall Dea Norge AS (28.0825%), and PGNiG Upstream Norway AS (11.9175%).
Whole crude
API gravity at 60/60° F.: 52.0
Density at 15° C., kg/l.: 0.7709
Total sulfur, wt %: 0.056
Mercaptan sulfur, ppm (wt): 2
Total nitrogen, ppm (wt): 88.0
Basic nitrogen, ppm (wt): 28.9
Acidity, mg KOH/g: 0.030
Vis. at 20° C., cst: 1.303
Vis. at 30° C., cst: 1.143
Vis. at 40° C., cst: 1.014
Vis. at 50° C., cst: 0.907
Pour point, °C.: –42
Wax, wt %: 2.0
Carbon residue, wt %: 0.20
Asphaltenes, wt %: 0.05
Vanadium, ppm (wt): < 2
Nickel, ppm (wt): < 2
Iron, ppm (wt): < 1
Ethane, wt %: 0.03
Propane, wt %: 0.34
Isobutane, wt %: 0.38
n-Butane, wt %: 1.24
Isopentane, wt %: 1.50
n-Pentane, wt %: 2.11
Cyclopentane, wt %: 0.16
C6 paraffins, wt %: 5.38
C6 naphthenes, wt %: 3.63
Benzene, wt %: 0.29
Light naphtha, C5 to 95° C.
Yield on crude, wt %: 17.25
Yield on crude, vol %: 19.15
Density at 15° C., kg/l.: 0.6900
Total sulfur, wt %: < 0.001
Mercaptan sulfur, ppm (wt): 1
Acidity, mg KOH/g: 0.008
Paraffins, wt %: 68.13
Naphthenes, wt %: 30.15
Aromatics, wt %: 1.71
n-Paraffins, wt %: 28.13
Research octane no.: 68
Heavy naphtha, 95-149° C.
Yield on crude, wt %: 24.85
Yield on crude, vol %: 25.40
Density at 15° C., kg/l.: 0.7527
Total sulfur, wt %: 0.001
Mercaptan sulfur, ppm (wt): 1
Total nitrogen, ppm (wt): 0.2
Acidity, mg KOH/g: 0.012
Paraffins, wt %: 45.84
Naphthenes, wt %: 41.32
Aromatics, wt %: 12.83
n-Paraffins, wt %: 22.72
Research octane no.: 53
149-175° C.
Yield on crude, wt %: 10.85
Yield on crude, vol %: 10.90
Density at 15° C., kg/l.: 0.7651
Total sulfur, wt %: 0.002
Mercaptan sulfur, ppm (wt): 1
Total nitrogen, ppm (wt): 0.3
Acidity, mg KOH/g: 0.014
Paraffins, wt %: 58.97
Naphthenes, wt %: 28.08
Aromatics, wt %: 12.96
n-Paraffins, wt %: 34.21
Kerosine, 175-232° C.
Yield on crude, wt %: 16.55
Yield on crude, vol %: 16.00
Density at 15° C., kg/l.: 0.7952
Total sulfur, wt %: 0.006
Mercaptan sulfur, ppm (wt): 2
Total nitrogen, ppm (wt): 0.5
Acidity, mg KOH/g: 0.020
Vis. at 40° C., cst: 1.292
Vis. at 60° C., cst: 1.017
Smoke point, mm: 28.5
Aromatics, vol %: 16.3
Naphthalenes, wt %: 1.06
Freezing point, °C.: –48.0
Cetane index (ASTM D4737-90): 47.4
Refractive index at 70° C.: 1.4168
Light gas oil, 232-342° C.
Yield on crude, wt %: 19.45
Yield on crude, vol %: 18.00
Density at 15° C., kg/l.: 0.8295
Total sulfur, wt %: 0.056
Mercaptan sulfur, ppm (wt): 3
Total nitrogen, ppm (wt): 9.6
Basic nitrogen, ppm (wt): 8.0
Acidity, mg KOH/g: 0.030
Vis. at 50° C., cst: 2.603
Vis. at 100° C., cst: 1.218
Aromatics, wt %: 21.60
Smoke point, mm: 21.2
Aromatics, vol %: 18.0
Naphthalenes, wt %: 4.73
Pour point, °C.: –15
Cloud point, °C.: –12
Freezing point, °C.: –11.5
Cetane index (ASTM D4737-90): 58.8
Refractive index at 70° C.: 1.4418
Wax, wt %: 4.5
Heavy gas oil, 342-369° C.
Yield on crude, wt %: 2.05
Yield on crude, vol %: 1.85
Density at 15° C., kg/l.: 0.8575
Total sulfur, wt %: 0.221
Total nitrogen, ppm (wt): 130.0
Basic nitrogen, ppm (wt): 53.0
Acidity, mg KOH/g: 0.030
Vis. at 50° C., cst: 7.241
Vis. at 100° C., cst: 2.549
Pour point, °C.: 15
Cloud point, °C.: 17
Cetane index (ASTM D4737-90): 71.8
Refractive index at 70° C.: 1.4573
Aniline point, °C.: 88.8
Wax, wt %: 15.0
Light vacuum gas oil, 369-509° C.
Yield on crude, wt %: 4.90
Yield on crude, vol %: 4.25
Density at 15° C., kg/l.: 0.8871
Total sulfur, wt %: 0.373
Total nitrogen, ppm (wt): 530.0
Basic nitrogen, ppm (wt): 180.0
Acidity, mg KOH/g: 0.020
Vis. at 60° C., cst: 17.010
Vis. at 100° C., cst: 5.881
Pour point, °C.: 33
Refractive index at 70° C.: 1.4722
Aniline point, °C.: 96.0
Wax, wt %: 16.3
Carbon residue, wt %: 0.02
Heavy vacuum gas oil, 509-550° C.
Yield on crude, wt %: 0.70
Yield on crude, vol %: 0.60
Density at 15° C., kg/l.: 0.9292
Total sulfur, wt %: 0.700
Total nitrogen, ppm (wt): 1,600.0
Basic nitrogen, ppm (wt): 435.0
Acidity, mg KOH/g: 0.020
Vis. at 60° C., cst: 141.300
Vis. at 100° C., cst: 26.300
Refractive index at 70° C.: 1.4958
Aniline point, °C.: 104.1
Wax, wt %: 17.2
Carbon residue, wt %: 1.02
550-585° C.
Yield on crude, wt %: 0.45
Yield on crude, vol %: 0.35
Density at 15° C., kg/l.: 0.9513
Total sulfur, wt %: 0.866
Total nitrogen, ppm (wt): 2,200.0
Basic nitrogen, ppm (wt): 605.0
Acidity, mg KOH/g: 0.020
Vis. at 60° C., cst: 406.900
Vis. at 100° C., cst: 55.690
Aniline point, °C.: 106.1
Wax, wt %: 16.8
Carbon residue, wt %: 3.18
Atmospheric residue (369°-FBP)
Yield on crude, wt %: 7.00
Yield on crude, vol %: 5.90
Density at 15° C., kg/l.: 0.9095
Total sulfur, wt %: 0.554
Total nitrogen, ppm (wt): 1,200.0
Basic nitrogen, ppm (wt): 374.0
Acidity, mg KOH/g: 0.020
Vis. at 60° C., cst: 38.030
Vis. at 100° C., cst: 11.060
Vis. at 120° C., cst: 7.11
Pour point, °C.: 36
Wax, wt %: 16.0
Carbon residue, wt %: 2.92
Asphaltenes, wt %: 0.50
Vanadium, ppm (wt): 3
Nickel, ppm (wt): < 2
Iron, ppm (wt): 4
Vacuum residue, 509°-FBP
Yield on crude, wt %: 2.10
Yield on crude, vol %: 1.65
Density at 15° C., kg/l.: 0.9673
Total sulfur, wt %: 0.984
Total nitrogen, ppm (wt): 2,800.00
Basic nitrogen, ppm (wt): 834.0
Acidity, mg KOH/g: 0.020
Vis. at 100° C., cst: 118.800
Vis. at 120° C., cst: 54.47
Vis. at 150° C., cst: 22.15
Pour point, °C.: 30
Wax, wt %: 14.4
Carbon residue, wt %: 9.78
Asphaltenes, wt %: 1.70
Vanadium, ppm (wt): 10
Nickel, ppm (wt): 4
Iron, ppm (wt): 15
550°-FBP
Yield on crude, wt %: 1.40
Yield on crude, vol %: 1.05
Density at 15° C., kg/l.: 0.9878
Total sulfur, wt %: 1.130
Total nitrogen, ppm (wt): 3,300.0
Basic nitrogen, ppm (wt): 1,036.0
Acidity, mg KOH/g: 0.020
Vis. at 100° C., cst: 334.700
Vis. at 120° C., cst: 131.90
Vis. at 150° C., cst: 45.20
Pour point, °C.: 30
Wax, wt %: 12.9
Carbon residue, wt %: 14.20
Asphaltenes, wt %: 2.40
Vanadium, ppm (wt): 14
Nickel, ppm (wt): 5
Iron, ppm (wt): 22
585°-FBP
Yield on crude, wt %: 0.95
Yield on crude, vol %: 0.70
Density at 15° C., kg/l.: 1.0057
Total sulfur, wt %: 1.250
Total nitrogen, ppm (wt): 3,900.0
Basic nitrogen, ppm (wt): 1,236.0
Acidity, mg KOH/g: 0.020
Vis. at 100° C., cst: 1,684.000
Vis. at 120° C., cst: 521.60
Vis. at 150° C., cst: 135.70
Pour point, °C.: 33
Wax, wt %: 11.1
Carbon residue, wt %: 19.30
Asphaltenes, wt %: 3.10
Vanadium, ppm (wt): 20
Nickel, ppm (wt): 8
Iron, ppm (wt): 30
