GUIDE TO WORLD CRUDES: New Statfjord assay reveals light, low-sulfur crude oil
Statfjord Blend 2010 crude is a light, low-sulfur North Sea oil is similar to Brent Blend, according to Statoil's web site, with a slightly lower sulfur content and less atmospheric residue. It results from a commingling of Statfjord, Snorre, Sygna, and satellites Statfjord North and East fields.
Statfjord field was discovered by Mobil in 1974; Statoil took over operatorship in January 1987 and is the operator. The Norwegian share of the field lies in Blocks 33/9 and 33/12 in production license 037, while the British part is in UK Block 211/25 in licenses 104 and 293.
Current partners are Statoil (44.34%), ExxonMobil Exploration & Production Norway AS (21.37%), ConocoPhillips Skandinavia AS (10.33%), AS Norske Shell (8.55%), ConocoPhillips (UK) Ltd. (4.84%), Centrica Resources Ltd. (9.68%), and Enterprise Oil Norge AS (0.89%).
The hydrocarbon reservoir formations on Statfjord lie at depths of 2,500-3,000 m and consist of sandstones with the oil and gas held in pores between the individual sand grains, says Statoil. These hydrocarbon-bearing sediments were all deposited in the Jurassic era, about 150 million years ago.
The field, which Statoil says one of the oldest producing fields on the Norwegian continental shelf and the largest oil discovery in the North Sea, is likely to remain in production until 2019-20.
Production
The field was developed with the Statfjord A, B, and C production platforms, all of which have concrete gravity-base structures that incorporate storage cells.
Statfjord A, which weighs 600,000 tonnes and stands 270 m tall, began production in November 1979. Statfjord B weighs 816,000 tonnes, stands 271 m, and began production in November 1982. And Statfjord C weighs 643,700 tonnes, stands 290 m, and began production in June 1985.
Roughly 140,000 b/d of oil are produced from the three platforms by the Statfjord unit, which unites all the licenses.
Oil is also produced from satellite fields tied back to Statfjord, bringing total output from the platforms to 470,000-480,000 b/d.
The production record for a single day on Statfjord was set on Jan. 16, 1987, when 850,204 bbl were produced.
Roughly 6 million cu m/day of gas are exported by the Statfjord unit.
Transport, storage
Statfjord oil production is loaded into shuttle tankers at the field and shipped to several ports in Northwest Europe with a new consignment departing about every other day.
The Norwegian share of gas from the field is piped for processing to Karsto north of Stavanger and on to continental Europe.
Britain's 14.53% of the gas travels by pipeline via Brent field to Scotland. Cargoes are allocated between the field licensees in proportion to their interests in the respective licenses.
Storage cells on Statfjord A hold 206,000 std. cu m (1.3 million bbl) of oil. Storage cells on the Statfjord B hold 302,000 std. cu m (1.9 million bbl) of oil, and storage cells on Statfjord C hold 302,000 std. cu m (1.9 million bbl) of oil.
Legend: 1ND = not detectable; HPLC = high performance liquid chromatography; DVPE = dry vapor pressure equivalent. 2Corrected in accordance with EN 228. 3Calculated density for 525o+ C. fraction. 4Not possible to distinguish between 3-Methylheptane and 1,3-Dimethylcyclohexane. |
Whole crude
Density at 15° C., kg/l.: 0.8270
Specific gravity at 60/60° F.: 0.8273
API gravity at 60/60° F.: 39.5
Dry oil density at 15° C.: 0.8269
Sulfur, mass %: 0.22
Total acid no., mg KOG/g: 0.05
Reid vapor pressure, kPa: 61.6
Pour point, °C.: 3
Kin. vis. at 20° C., cst: 4.87
Kin. vis. at 40° C., cst: 3.06
Nitrogen, mg/kg: 890
Hydrogen sulfide, mass %: ND1
Vanadium, mg/kg: 1.6
Nickel, mg/kg: 1.1
Sodium, mg/kg: 7.0
Salt as NaCl, mg/l.: 19.5
Wax content, mass %: 7.0
Flash point, °C.: <10
Water content, mass %: 0.06
Pentanes to 65° C.
Yield on crude, mass %: 4.68
Yield on crude, vol %: 5.89
Density at 15° C., kg/l.: 0.6455
Specific gravity at 60/60° F.: 0.6455
API gravity at 60/60° F.: 87.7
Mercaptan sulfur, mg/kg: <3
n-Paraffins, mass %: 52.1
i-Paraffins, mass %: 39.1
Naphthenes, mass %: 7.3
Aromatics (incl. benzene), mass %: 1.4
n-Paraffins, vol %: 53.2
i-Paraffins, vol %: 39.6
Naphthenes, vol %: 6.2
Aromatics (incl. benzene), mass %: 1.1
Vapor pressure (DVPE), kPa: 113.1
Research octane no. (RON): 73.3
Motor octane no. MON: 71.7
Research octane no. (RON): 273.1
Motor octane no. (MON): 271.5
65-90° C.
Yield on crude, mass %: 4.00
Yield on crude, vol %: 4.48
Density at 15° C., kg/l.: 0.7259
Specific gravity at 60/60° F.: 0.7261
API gravity at 60/60° F.: 63.4
Sulfur, mass %: <0.001
Mercaptan sulfur, mg/kg: 8
n-Paraffins, mass %: 28.2
i-Paraffins, mass %: 24.1
Naphthenes, mass %: 42.2
Aromatics (incl. benzene), mass %: 5.5
Benzene, mass %: 4.7
n-Paraffins, vol %: 30.5
i-Paraffins, vol %: 25.5
Naphthenes, vol %: 39.4
Aromatics (incl. benzene), mass %: 4.6
Benzene, vol %: 3.9
Vapor pressure (DVPE), kPa: 33.4
Research octane no. (RON): 65.4
Motor octane no. MON: 64.5
Research octane no. (RON): 265.2
Motor (MON): 264.3
90-150° C.
Yield on crude, mass %: 12.64
Yield on crude, vol %: 13.61
Density at 15° C., kg/l.: 0.7547
Specific gravity at 60/60° F.: 0.7549
API gravity at 60/60° F.: 55.9
Sulfur, mass %: 0.001
Mercaptan sulfur, mg/kg: 8
n-Paraffins, mass %: 20.9
i-Paraffins, mass %: 22.1
Naphthenes, mass %: 42.5
Aromatics (incl. benzene), mass %: 14.5
Benzene, mass %: 0.3
n-Paraffins, vol %: 22.6
i-Paraffins, vol %: 23.3
Naphthenes, vol %: 41.5
Aromatics (incl. benzene), mass %: 12.6
Benzene, vol %: 0.3
Flash point, °C.: <10
150-180° C.
Yield on crude, mass %: 5.51
Yield on crude, vol %: 5.82
Density at 15° C., kg/l.: 0.7827
Specific gravity at 60/60° F.: 0.7830
API gravity at 60/60° F.: 49.2
Sulfur, mass %: 0.012
Mercaptan sulfur, mg/kg: <3
Copper corrosion: 1a
Total acid no., mg KOH/g: <0.01
n-Paraffins, mass %: 19.8
i-Paraffins, mass %: 25.1
Naphthenes, mass %: 35.8
Aromatics, mass %: 19.3
n-Paraffins, vol %: 21.4
i-Paraffins, vol %: 26.3
Naphthenes, vol %: 35.0
Aromatics, vol %: 17.4
Aromatics (HPLC)
Total, mass %: 17.9
Monoaromatics, mass %: 17.9
Diaromatics, mass %: <0.1
Polycyclic aromatics, mass %: <0.1
Naphthalenes, vol %: 0.02
Aniline point, °C.: 52.0
Smoke point, mm: 25.0
Flash point, °C.: 38.0
Freezing point, °C.: <-60
Cetane index (D-976): 31.3
Calculated cetane index (D-4737): 36.0
Kin. vis. at 20° C., cst: 1.10
Kin. vis. at 50° C., cst: 0.77
Nitrogen, mg/kg: 2
Distillation D-86 (50%), °C.: 160.3
180-240° C.
Yield on crude, mass %: 10.85
Yield on crude, vol %: 11.10
Density at 15° C., kg/l.: 0.8087
Specific gravity at 60/60° F.: 0.8090
API gravity at 60/60° F.: 43.4
Sulfur, mass %: 0.095
Total acid no., mg KOH/g: 0.01
Aromatics (HPLC)
Total, mass %: 19.3
Monoaromatics, mass %: 15.7
Diaromatics, mass %: 3.6
Polycyclic aromatics, mass %:<0.1
Naphthalenes, vol %: 2.24
Aniline point, °C.: 60.0
Smoke point, mm: 23.0
Freezing point, °C.: –50.5
Cloud point, °C.: <–51
Cold-filter plugging point, °C.: <–47
Pour point, °C.: <–48
Cetane no.: 47.4
Cetane index (D-976): 43.1
Calculated cetane index (D-4737): .43.6
Kin. vis. at 20° C., cst: 1.86
Kin. vis. at 50° C., cst: 1.19
Nitrogen, mg/kg: 2
Distillation D-86 (50%), °C.: 204.9
240-320°+ C.
Yield on crude, mass %: 15.73
Yield on crude, vol %: 15.44
Density at 15° C., kg/l.: 0.8426
Specific gravity at 60/60° F.: 0.8430
API gravity at 60/60° F.: 36.4
Sulfur, mass %: 0.095
Total acid no., mg KOH/g: 0.03
Aromatics (HPLC)
Total, mass %: 24.7
Monoaromatics, mass %: 14.7
Diaromatics, mass %: 9.8
Polycyclic aromatics, mass %: 0.2
Aniline point, °C.: 70.3
Cloud point, °C.: –17
Cold-filter plugging point, °C.: –21
Pour point, °C.: –18
Cetane no.: 55.6
Cetane index (D-976): 50.8
Calculated cetane index (D-4737): 52.7
Kin. vis. at 20° C., cst: 4.99
Kin. vis. at 50° C., cst: 2.53
Nitrogen, mg/kg: 15
Basic nitrogen, mass %: 0.001
Distillation D-86 (50%), °C.: 272.1
320-375° C.
Yield on crude, mass %: 8.96
Yield on crude, vol %: 8.54
Density at 15° C., kg/l.: 0.8678
Specific gravity at 60/60° F.: 0.8682
API gravity at 60/60° F.: 31.5
Sulfur, mass %: 0.276
Total acid no., mg KOH/g: 0.06
Aromatics (HPLC)
Total, mass %: 27.1
Monoaromatics, mass %: 16.6
Diaromatics, mass %: 7.9
Polycyclic aromatics, mass %: 2.6
Aniline point, °C.: 80.1
Watson K-factor: 11.9
Cloud point, °C.: 9
Cold-filter plugging point, °C.: 10
Pour point, °C.: 9
Cetane no.: 60.3
Cetane index (D-976): 51.7
Calculated cetane index (D-4737): 63.6
Conradson carbon residue (CCR), mass %: <0.10
Kin. vis. at 20° C., cst: 16.73
Kin. vis. at 50° C., cst: 6.27
Kin. vis. at 100° C., cst: 2.31
Nitrogen, mg/kg: 210
Basic nitrogen, mass %: 0.009
Refractive index @ 67° C.: 1.464
Distillation D-86 (50%), °C.: 334.6
375-420° C.
Yield on crude, mass %: 6.93
Yield on crude, vol %: 6.45
Density at 15° C., kg/l.: 0.8887
Specific gravity at 60/60° F.: 0.8892
API gravity at 60/60° F.: 27.6
Sulfur, mass %: 0.314
Total acid no., mg KOH/g: 0.05
Aniline point, °C.: 89.7
Watson K-factor: 12.0
Pour point, °C.: 27
Conradson carbon residue (CCR), mass %: <0.10
Kin. vis. at 50° C., cst: 17.1
Kin. vis. at 100° C., cst: 4.98
Vanadium, mg/kg: <0.1
Nickel, mg/kg: <0.1
Nitrogen, mg/kg: 580
Basic nitrogen, mass %: 0.023
Refractive index @ 67° C.: 1.475
375-420° C.
Yield on crude, mass %: 6.93
Yield on crude, vol %: 6.45
Density at 15° C., kg/l.: 0.8887
Specific gravity at 60/60° F.: 0.8892
API gravity at 60/60° F.: 27.6
Sulfur, mass %: 0.314
Total acid no., mg KOH/g: 0.05
Aniline point, °C.: 89.7
Watson K-factor: 12.0
Pour point, °C.: 27
Conradson carbon residue (CCR), mass %: <0.10
Kin. vis. at 50° C., cst: 17.1
Kin. vis. at 100° C., cst: 4.98
Vanadium, mg/kg: <0.1
Nickel, mg/kg: <0.1
Nitrogen, mg/kg: 580
Basic nitrogen, mass %: 0.023
Refractive index @ 67° C.: 1.475
420-525° C.
Yield on crude, mass %: 14.10
Yield on crude, vol %: 12.86
Density at 15° C., kg/l.: 0.9070
Specific gravity at 60/60° F.: 0.9075
API gravity at 60/60° F.: 24.4
Sulfur, mass %: 0.393
Total acid no., mg KOH/g: 0.04
Aniline point, °C.: 96.1
Watson K-factor: 12.0
Pour point, °C.: 39
Conradson carbon residue (CCR), mass %: <0.11
Kin. vis. at 50° C., cst: 50.12
Kin. vis. at 100° C., cst: 9.14
Vanadium, mg/kg: <0.1
Nickel, mg/kg: <0.1
Nitrogen, mg/kg: 1,190
Basic nitrogen, mass %: 0.040
Refractive index @ 67° C.: 1.486
375° C.
Yield on crude, mass %: 34.75
Yield on crude, vol %: 30.95
Density at 15° C., kg/l.: 0.9289
Specific gravity at 60/60° F.: 0.9294
API gravity at 60/60° F.: 20.7
Sulfur, mass %: 0.506
Total acid no., mg KOH/g: 0.07
Aniline point, °C.: 93.0
Watson K-factor: 11.9
Pour point, °C.: 33
Conradson carbon residue (CCR), mass %: 4.89
Asphaltenes, mass %: <0.5
n-Pentanes insolubles, mass %: 1.8
Ash, mass %: 0.025
Kin. vis. at 50° C., cst: 164
Kin. vis. at 100° C., cst: 20.8
Vanadium, mg/kg: 4.2
Nickel, mg/kg: 3.3
Nitrogen, mg/kg: 2,390
Basic nitrogen, mass %: 0.074
Refractive index @ 67° C.: 1.504
525°+ C.
Yield on crude, mass %: 13.71
Yield on crude, vol %: 11.64
Density at 15° C., kg/l.: 30.9745
Specific gravity at 60/60° F.: 0.9751
API gravity at 60/60° F.: 13.6
Sulfur, mass %: 0.708
Aniline point, °C.: 95.8
Watson K-factor: 11.7
Pour point, °C.: 42
Conradson carbon residue (CCR), mass %: 12.6
Asphaltenes, mass %: 0.70
n-Pentanes insolubles, mass %: 5.6
Ash, mass %: 0.068
Kin. vis. at 80° C., cst: 785
Kin. vis. at 100° C., cst: 251
Vanadium, mg/kg: 10.8
Nickel, mg/kg: 8.9
Nitrogen, mg/kg: 4,600
Basic nitrogen, mass %: 0.134
Penetration at 25° C.: 290
Composition, mass %
Normal paraffins
Methane: <0.01
Ethane: 0.02
Propane: 0.53
Butane: 1.58
Pentane: 1.70
Hexane: 1.44
Heptane: 1.28
Octane: 1.20
Nonane: 1.00
Total n-paraffins: 8.76
C4 hydrocarbons
i-Butane: 0.32
C5 hydrocarbons
Isoparaffins
2,2-Dimethylpropane: <0.01
i-Pentane: 1.04
Total C5 i-paraffins: 1.04Naphthenes
Cyclopentane: 0.23
C6 hydrocarbons
Isoparaffins
2,2-Dimethylbutane: 0.02
2,3-Dimethylbutane: 0.07
2-Methylpentane: 0.74
3-Methylpentane: 0.45
Total C6 i-paraffins: 1.27Naphthenes
Methylcyclopentane (incl. 2,2-Dimethylpentane): 0.83
Cyclohexane: 0.87
Total C6 naphthenes: 1.70Aromatics
Benzene: 0.29
C7 hydrocarbons
Isoparaffins
2,2,3-Trimethylbutane: <0.01
3,3-Dimethylpentane: 0.01
2,4-Dimethylpentane: 0.05
2-Methylhexane: 0.42
2,3-Dimethylpentane: 0.10
3-Methylhexane: 0.47
Total C7 i-paraffins: 1.05Naphthenes
cis-1,3-Dimethylcyclopentane: 0.19
trans-1,3-Dimethylcyclopentane: 0.18
trans-1,2-Dimethylcyclopentane: 0.40
Methylcyclohexane: 1.52
Ethylcyclopentane: 0.14
1,1-Dimethylcyclopentane: 0.10
Total C7 naphthenes: 2.53
Aromatics
Toluene: 0.81
C8 hydrocarbons
Isoparaffins
2,2,4-Trimethylpentane: <0.01
2,5-Dimethylhexane: 0.05
2,4-Dimethylhexane: 0.06
3,4-Dimethylhexane: 0.01
3,3-Dimethylhexane: 0.01
2,3-Dimethylhexane (incl. naphthenic compound): 0.09
2-Methyl-3-ethylpentane: 0.02
2-Methylheptane: 0.45
4-Methylheptane: 0.15
3-Methylheptane: 4<0.01
2,3,4-Trimethylpentane: 0.02
Total C8 i-paraffins: 0.87Naphthenes
1,1,3-Trimethylcyclopentane (incl. 2,2-Dimethylhexane): 0.10
trans, cis-1,2,4-Trimethylcyclopentane: 0.11
trans,cis-1,2,3-Trimethylcyclopentane: 0.13
trans-1,4-Dimethylcyclohexane: 0.13
1,1-Dimethylcyclohexane: 0.05
trans-1-Methyl-3-ethylcyclopentane: 0.06
cis-1-Methyl-3-ethylcyclopentane: 0.05
trans-1-Methyl-2-ethylcyclopentane: 0.16
trans-1,2-Dimethylcyclohexane: 0.18
2-Propylcyclopentane: 0.02
cis-1,2-Dimethylcyclohexane: 0.11
Ethylcyclohexane: 0.51
1-Propylcyclopentane: 0.18br /cis,cis-1,2,4-Trimethylcyclopentane: 0.02
1-Methyl-1-ethylcyclopentane: 0.02
cis-1,3-Dimethylcyclohexane (incl. naphthenic compound): 40.62
Total C8 naphthenes: 2.44Aromatics
Ethylbenzene: 0.27
m-Dimethylbenzene (m-xylene): 0.48
p-Dimethylbenzene (p-xylene): 0.25
o-Dimethylbenzene (o-Xylene): 0.33
Total C8 aromatics: 1.33
C9 hydrocarbons
Isoparaffins
3,5-Dimethylheptane: 0.11
4-Methyloctane: 0.13
2-Methyloctane: 0.17
3-Methyloctane: 0.23
2,3,4-Trimethylhexane: <0.01
Unidentified paraffin: 0.10
Total C9 i-paraffins: 0.75Naphthenes
1,1,3-Trimethylcyclohexane: 0.19
1-Methyl-2-propylcyclopentane: 0.10
1-Methyl-3-ethylcyclohexane: 0.16
1-Methyl-4-ethylcyclohexane: 0.11
1,1,4-Trimethylcyclohexane: 0.07
Unidentified naphthenes: 0.11
Total C9 naphthenes: 0.72
Total identified: 24.09
Total unidentified: 0.22
Total C10+: 75.69
Editor's note: Statoil's assay report contained the following: "A commercial assay was carried out on a representative sample of the crude. The contents of this report are for guidance only and Statoil accepts no responsibility for any errors that it may contain."
More Oil & Gas Journal Current Issue Articles
More Oil & Gas Journal Archives Issue Articles
View Oil and Gas Articles on PennEnergy.com
