GUIDE TO WORLD CRUDES: Enterprise assays fields in Norway, the UK, and Italy

Except where otherwise noted, Table 1 lists the test methods used to determine the assay properties.

Jotun, Norwegian North Sea

Jotun crude is a light, low-sulfur crude. Fig. 1 shows a true boiling point (TBP) distillation curve of the crude.

The Jotun oil field came on stream in October 1999, starting with production from Block 25/8a of the Norwegian sector of the North Sea. It consists of the Elli discovery made in 1994 and the Tau discovery made in 1995. Enterprise holds a 45% interest in the field, which is operated by Esso Norway.

Production has reached rates of more than 140,000 bo/d.

An FPSO (floating, production, storage, and offloading) unit produces the oil, and Enter prise's share is transported via shuttle tankers provided un der a contract of affreightment with Navion AS, Stavanger, Norway.

SGS Redwood Ser vices, Ellesmere Port, prepared the following assay from a preproduction sample ta ken in September 1999:

Whole crude

Density at 15° C., kg/cu m: 835.8
Gravity, °API: 37.7
Sulfur, wt %: 0.25
Viscosity at 20° C., sq mm/sec: 6.495
Viscosity at 30° C., sq mm/sec: 5.008
Pour point, °C.: -3
Acidity, mg KOH/g (IP 123): 0.09
Microcarbon residue, wt %: 1.3
Asphaltenes, wt %: 0.12
Vanadium, mg/kg: 2.7
Nickel, mg/kg: 0.7
Sodium, mg/kg: 6.6
Molybdenum, mg/kg: 0.1
Hydrogen sulfide, ppm: <1
Salt content (NaCl), wt %: 0.0062
Water content, wt %: 0.182
Light ends recovery, wt %
Methane: <0.01
Ethane: <0.01
Propane: 0.16
iso-Butane: 0.14
n-Butane: 0.43
Total C₁ to C₄: 0.73
iso-Pentane: 0.55
n-Pentane: 0.90

Naphthas and kerosine

Boiling range, °C.: IBP-95
Yield, wt %: 7.6
Yield, vol %: 9.3
Density at 15° C., kg/cu cm: 680.7
Sulfur, wt %: 0.0003
Mercaptan sulfur ppm: <3
Paraffins, wt %: 71.9
Olefins, wt %: <0.1
Naphthalenes, wt %: 26.9
Aromatics, wt %: 1.2
Polynaphthenes, wt %: <0.1
>200° C., wt %: <0.1

Boiling range, °C.: 95 -175
Yield, wt %: 13.8
Yield, vol %: 15.4
Density at 15° C., kg/cu cm: 750.7
Sulfur, wt %: 0.0010
Mercaptan sulfur, ppm: <3
Paraffins, wt %: 52.5
Olefins, wt %: 0.1
Naphthalenes, wt %: 37.8
Aromatics, wt %: 8.6
Polynaphthenes, wt %: 0.9
>200° C., wt %: 0.1

Boiling range, °C.: IBP-150
Yield, wt %: 16.8
Yield, vol %: 19.7
Density at 15° C., kg/cu cm: 718.3
Sulfur, wt %: 0.0004
Mercaptan sulfur, ppm: <3
Paraffins, wt %: 59.4
Olefins, wt %: <0.1
Naphthalenes, wt %: 36.2
Aromatics, wt %: 4.3
Polynaphthenes, wt %: 0.1
>200° C., wt %: <0.1

Boiling range, °C.: 150-230
Yield, wt %: 14.9
Yield, vol %: 15.8
Density at 15° C., kg/cu cm: 788.9
Sulfur, wt %: 0.0043
Mercaptan sulfur, ppm: <3
Viscosity at 40° C., sq mm/sec: 1.098
Viscosity at 60° C., sq mm/sec: 0.8725
Acidity, mg KOH/g: 0.022
Smoke point, mm: 29
Freeze point, °C.: -59.5
Aniline point, °C.: 61.4
Cetane index: 43.5
Hydrogen content, wt %: 13.1
Color stability: <0.5
Naphthalenes, vol %: 0.71

Gas oil and distillates

Boiling range, °C.: 230-350
Yield, wt %: 25.1
Yield, vol %: 25.1
Density at 15° C., kg/cu m: 837.3
Sulfur, wt %: 0.08
Viscosity at 50° C.: sq mm/sec: 2.667
Cloud point, ° C.: -12
Pour point, ° C.: -12
Wax content, wt %: 0.55
Total nitrogen, mg/kg: 14
Acidity, mg KOH/g: 0.056
Aniline point, °C: 73.4
Cetane index: 53.5
Color stability: 0.5

Boiling range, °C.: 350-375
Yield, wt %: 4.7
Yield, vol %: 4.5
Density at 15° C., kg/cu m: 864.6
Sulfur, wt %: 0.23
Viscosity at 50° C., sq mm/sec: 6.628
Cloud point, ° C.: +18
Pour point, ° C: +15
Wax content, wt %: 15.0
Total nitrogen, mg/kg: 122
Aniline point, °C.: 82.7
Cetane index: 53.0

Boiling range, °C.: 375-550
Yield, wt %: 23.4
Yield, vol %: 21.8
Density at 15° C., kg/cu m: 897.0
Sulfur, wt %: 0.37
Viscosity at 60° C., sq mm/sec: 19.28
Viscosity at 80° C., sq mm/sec: 10.39
Viscosity at 100° C: sq mm/sec: 6.417
Wax content, wt %: 15.9
Total nitrogen, mg/kg: 529
Basic nitrogen, mg/kg: 167
Acidity, mg KOH/g: 0.081
Aniline point, °C.: 94.0
Refractive index at 60° C.: 1.4822

Residues

Boiling range, °C.: 350+
Yield, wt %: 43.1
Yield, vol %: 39.2
Density at 15 ° C., kg/cu m: 914.2
Sulfur, wt %: 0.56
Viscosity at 50° C., sq mm/sec: 73.64
Viscosity at 60° C., sq mm/sec: 46.21
Viscosity at 80° C., sq mm/sec: 21.72
Viscosity at 100° C., sq mm/sec: 12.14
Viscosity at 120° C., sq mm/sec: 6.9
Viscosity at 150° C., sq mm/sec: 3.9
Pour point, °C.: +39
Wax content, wt %: 12.7
Total nitrogen, mg/kg: 1,535
Acidity, mg KOH/g: 0.22
Microcarbon residue, wt %: 3.4
Asphaltenes, wt %: 0.36
Vanadium, mg/kg: 6
Nickel, mg/kg: 2

Boiling range, °C.: 550+
Yield, wt %: 15.0
Yield, vol %: 12.9
Density at 15° C., kg/cu m: 973.2
Sulfur, wt %: 0.94
Viscosity at 80° C., sq mm/sec: 394.0
Viscosity at 100° C., sq mm/sec: 143.1
Viscosity at 120° C., sq mm/sec: 65
Viscosity at 150° C., sq mm/sec: 26
Penetration at 25° C.: >560
Softening point, °C.: too soft
Total nitrogen, mg/kg: 3,195
Microcarbon residue, wt %: 10.5
Asphaltenes, wt %: 1.08
Vanadium, mg/kg: 16
Nickel, mg/kg: 6

Dewaxed oil

Density at 15° C., kg/cu m: 916.8
Sulfur, wt %: 0.45
Viscosity at 40° C., sq mm/sec: 73.70
Viscosity at 60° C., sq mm/sec: 28.33
Viscosity at 100° C., sq mm/sec: 8.033
Viscosity index: 66
Pour point, °C.: -33

Pierce, UK North Sea

Pierce crude oil is a light, low-sulfur content crude with good refining properties. It is suitable for lube oil production. Fig. 2 shows a TBP distillation curve of the crude.

The Pierce oil field began production in February 1999 from Blocks 23/27 and 23/22a of the UK sector of the North Sea. Enterprise is the operator of the field and has a 74% equity interest. Enterprise markets 100% of its production, however.

In late 1999, the field reached peak production rates of 55,000 bo/d. Since completion of a debottlenecking project in February 2000, the field has produced peak rates in excess of 68,000 bo/d.

Enterprise produces the oil through a leased FPSO, the Berge Hugin, which is operated by the Pierce Production Co. Like production from the Jotun field, Pierce oil is transported via shuttle tankers provided under a contract with Navion (Fig. 3).

The following crude assay was prepared by SGS based on September 1999 production:

Whole crude

Density at 15° C., kg/cu m: 835.4
Gravity, °API: 37.8
Sulfur, wt %: 0.15
Viscosity at 20° C., sq mm/s: 9.498
Viscosity at 30° C., sq mm/s: 7.002
Pour point, °C.: zero
Acidity, mg KOH/g (IP 123): 0.14
Microcarbon residue, wt %: 1.8
Asphaltenes, wt %: 0.21
Vanadium, mg/kg: 0.3
Nickel, mg/kg: 0.9
Sodium, mg/kg: 3.5
Molybdenum, mg/kg: <0.1
Hydrogen sulfide, ppm: <1
Salt content (NaCl), wt %: 0.0008
Water content, wt %: 0.069
Light ends recovery, wt %
Methane: <0.01
Ethane: <0.01
Propane: 0.29
iso-Butane: 0.21
n-Butane: 0.75
Total C₁ to C₄: <0.01
iso-Pentane: 0.65
n-Pentane: <0.01

Naphthas and kerosine

Boiling range, °C.: IBP-95
Yield, wt %: 9.5
Yield, vol %: 11.6
Density at 15° C., kg/cu cm: 684.2
Sulfur, wt %: 0.0002
Mercaptan sulfur, ppm: <3
Paraffins, wt %: 68.7
Olefins, wt %: <0.1
Naphthalenes, wt %: 26.4
Aromatics, wt %: 4.9
Polynaphthalenes, wt %: <0.1
>200° C., wt %: <0.1

Boiling range, °C.: 95-175
Yield, wt %: 13.3
Yield, vol %: 14.6
Density at 15° C., kg/cu cm: 763.6
Sulfur, wt %: 0.0009
Mercaptan sulfur, ppm: <3
Paraffins, wt %: 42.0
Olefins, wt %: <0.1
Naphthalenes, wt %: 38.3
Aromatics, wt %: 18.1
Polynaphthalenes, wt %: 1.0
>200° C., wt %: 0.5

Boiling range, °C.: IBP-150
Yield, wt %: 18.6
Yield, vol %: 21.7
Density at 15° C., kg/cu cm: 716.0
Sulfur, wt %: 0.0002
Mercaptan sulfur, ppm: <3
Paraffins, wt %: 57.6
Olefins, wt %: <0.1
Naphthalenes, wt %: 30.4
Aromatics, wt %: 12.0
Polynaphthalenes, wt %: <0.1
>200° C., wt %: <0.1

Boiling range, °C.: 150-230
Yield, wt %: 13.7
Yield, vol %: 14.5
Density at 15° C., kg/cu cm: 789.8
Sulfur, wt %: 0.0032
Mercaptan sulfur, ppm: <3
Viscosity at 40° C., sq mm/sec: 1.084
Viscosity at 60° C., sq mm/sec: 0.8572
Acidity, mg KOH/g: 0.04
Smoke point, mm: 28
Freeze point, °C.: -52.5
Aniline point, °C.: 59.5
Cetane index: 42.0
Hydrogen content, wt %: 11.8
Color stability: <0.5
Naphthalenes, vol %: 1.76

Gas oil and distillates

Boiling range, °C.: 230-350
Yield, wt %: 21.3
Yield, vol %: 21.2
Density at 15 °C., kg/cu m: 837.9
Sulfur, wt %: 0.06
Viscosity at 50° C., sq mm/sec: 2.768
Cloud point, °C.: -11
Pour point, °C.: -15
Wax content, wt %: 1.8
Total nitrogen, mg/kg: 16
Acidity, mg KOH/g: 0.10
Aniline point, °C.: 75.8
Cetane index: 54.0
Color stability: 0.5

Boiling range, °C.: 350-375
Yield, wt %: 4.6
Yield, vol %: 4.5
Density at 15° C., kg/cu m: 863.5
Sulfur, wt %: 0.15
Viscosity at 50° C., sq mm/sec: 6.914
Cloud point, °C.: +18
Pour point, °C.: +15
Wax content, wt %: 13.7
Total nitrogen, mg/kg 116
Aniline point, °C.: 85.4
Cetane index: 53.5

Boiling range, °C.: 375-550
Yield, wt %: 24.6
Yield, vol %: 23.0
Density at 15 °C., kg/cu m: 895.3
Sulfur, wt %: 0.22
Viscosity at 60° C., sq mm/sec: 20.07
Viscosity at 80° C., sq mm/sec: 10.73
Viscosity at 100° C., sq mm/sec: 6.620
Wax content, wt %: 13.9
Total nitrogen, mg/kg: 489
Basic nitrogen, mg/kg: 170
Acidity, mg KOH/g: 0.17
Aniline point, °C.: 97.0
Refractive index at 60° C.: 1.4793

Residues

Boiling range, °C.: 350+
Yield, wt %: 46.3
Yield, vol %: 42.4
Density at 15° C., kg/cu m: 911.2
Sulfur, wt %: 0.31
Viscosity at 50° C., sq mm/sec: 80.67
Viscosity at 60° C., sq mm/sec: 50.07
Viscosity at 80° C., sq mm/sec: 23.46
Viscosity at 100° C., sq mm/sec: 13.09
Viscosity at 120° C., sq mm/sec: 8.0
Viscosity at 150° C., sq mm/sec: 4.6
Pour point, °C.: +27
Wax content, wt %: 15.5
Total nitrogen, mg/kg: 911
Acidity, mg KOH/g: 0.39
Microcarbon residue, wt %: 3.1
Asphaltenes, wt %: 0.40
Vanadium, mg/kg: 0.4
Nickel, mg/kg: 1.7

Boiling range, °C.: 550+
Yield, wt %: 17.1
Yield, vol %: 14.9
Density at 15° C., kg/cu m (IP 190): 959.4
Sulfur, wt %: 0.46
Viscosity at 80° C., sq mm/sec: 353.5
Viscosity at 100° C., sq mm/sec: 140.4
Viscosity at 120° C., sq mm/sec: 67
Viscosity at 150° C., sq mm/sec: 28
Penetration at 25° C.: >560
Softening point, °C.: too soft
Total nitrogen, mg/kg: 2,296
Microcarbon residue, wt %: 9.5
Asphaltenes, wt %: 0.78
Vanadium, mg/kg: 2.0
Nickel, mg/kg: 6.0

Dewaxed oil

Density at 15° C., kg/cu m: 911.7
Sulfur, wt %: 0.26
Viscosity at 40° C., sq mm/sec: 74.48
Viscosity at 60° C., sq mm/sec: 28.37
Viscosity at 100° C., sq mm/sec: 8.140
Viscosity index: 69
Pour point, °C.: -33

Tempa Rossa, Italy

Tempa Rossa crude oil is a heavy, high-sulfur crude oil. As such, the oil is better suited for asphalt or gasification plant feedstock than refinery feedstock.

Fig. 4 shows a TBP distillation curve of the crude. Tempa Rossa crude has more than twice as much residue volume, 36.6% vs. 12.9% and 14.9%, than the Jotun and Pierce crudes.

Oil is available for purchase from Agip Petroli's oil refinery in Taranto, Italy.

Enterprise has a 25% equity interest in the Tempa Rossa field, located in Italy. TotalFinaElf, ENI, and ExxonMobil Corp. also each owns a 25% interest.

The owners are working towards approval of the project development plan this year. The long production test commenced on March 2000.

SGS provided the following production assay in September 2000 to Enterprise. Enterprise plans to update this assay later this year with an assay from a different production area.

Whole crude

Density at 15° C., kg/cu m: 930.9
Gravity, °API: 20.4
Sulfur, wt %: 5.44
Viscosity at 20° C., sq mm/sec: 123.1
Viscosity at 30° C., sq mm/sec: 89.56
Pour point, ° C.: -36
Acidity, mg KOH/g (IP 213): 0.05
Microcarbon residue, wt %: 13.5
Asphaltenes, wt %: 9.3
Vanadium, mg/kg: 29
Nickel, mg/kg: 31
Sodium, mg/kg: 0.2
Molybdenum, mg/kg: 1.4
Hydrogen sulfide, ppm: 9
Salt content (NaCl), wt %: 0.0008
Water content, wt %: 0.048
Light ends recovery, wt %
Methane: <0.01
Ethane: <0.01
Propane: 0.29
iso-Butane: 0.18
n-Butane: 0.85
iso-Pentane: 0.72
n-Pentane: 1.19

Naphthas and kerosine

Boiling range, °C.: IBP-95
Yield, wt %: 7.5
Yield, vol %: 10.7
Density at 15° C., kg/cu cm: 654.7
Sulfur, wt %: 0.02
Mercaptan sulfur, ppm: 133
Paraffins, wt %: 88.8
Olefins, wt %: <0.1
Naphthalenes, wt %: 8.7
Aromatics, wt %: 2.5
Polynaphthenes, wt %: <0.1
>200° C., wt %: <0.1

Boiling range, °C.: 95-175
Yield, wt %: 9.6
Yield, vol %: 11.9
Density at 15° C., kg/cu cm: 754.5
Sulfur, wt %: 0.33
Mercaptan sulfur, ppm: 106
Paraffins, wt %: 55.1
Olefins, wt %: 0.1
Naphthalenes, wt %: 24.6
Aromatics, wt %: 19.4
Polynaphthenes, wt %: 0.1
>200° C., wt %: 0.6

Boiling range, °C.: IBP-150
Yield, wt %: 14.3
Yield, vol %: 19.2
Density at 15° C., kg/cu cm: 692.6
Sulfur, wt %: 0.11
Mercaptan sulfur, ppm: 90
Paraffins, wt %: 78.2
Olefins, wt %: <0.1
Naphthalenes, wt %: 13.1
Aromatics, wt %: 8.7
Polynaphthenes, wt %: <0.1
>200° C., wt %: <0.1

Boiling range, °C.: 150-230
Yield, wt %: 9.3
Yield, vol %: 10.9
Density at 15° C., kg/cu cm: 792.9
Sulfur, wt %: 0.86
Mercaptan sulfur, ppm: 27
Viscosity at 40° C., sq mm/sec: 1.077
Viscosity at 60° C., sq mm/sec: 0.8547
Acidity, mg KOH/g: 0.04
Smoke point, mm: 25
Freeze point, °C.: -55.0
Aniline point, °C.: 54.6
Cetane index: 41.5
Hydrogen content, wt %: 14.4
Color stability: stable <0.5
Naphthalenes, vol %: 0.23

Gas oil and distillates

Boiling range, °C.: 230-350
Yield, wt %: 14.9
Yield, vol %: 15.9
Density at 15° C., kg/cu m: 870.5
Sulfur, wt %: 3.26
Viscosity at 50° C., sq mm/sec: 2.760
Cloud point, °C.: -12
Pour point, °C.: -12
Wax content, wt %: 0.7
Total nitrogen, mg/kg: 140
Acidity, mg KOH/g: 0.05
Aniline point, °C.: 56.4
Cetane index: 43.0
Color stability: 1.0 stable

Boiling range, °C.: 350-375
Yield, wt %: 3.3
Yield, vol %: 3.3
Density at 15° C., kg/cu m: 929.3
Sulfur, wt %: 4.75
Viscosity at 50° C., sq mm/sec: 9.100
Cloud point, °C.: +16
Pour point, °C.: +15
Wax content, wt %: 13.3
Total nitrogen, mg/kg: 665
Aniline point, °C.: 53.8
Cetane index: 37.5

Boiling range, °C.: 375-500
Yield, wt %: 14.8
Yield, vol %: 14.1
Density at 15° C., kg/cu m: 977.6
Sulfur, wt %: 5.10
Viscosity at 60° C., sq mm/sec: 50.40
Viscosity at 80° C., sq mm/sec: 21.22
Viscosity at 100° C., sq mm/sec: 11.05
Wax content, wt %: 6.5
Total nitrogen, mg/kg: 1,140
Basic nitrogen, mg/kg: 429
Acidity, mg KOH/g: 0.03
Aniline point, °C.: 55.8
Refractive index at 60° C.: 1.5248

Residues

Boiling range, °C.: 350+
Yield, wt %: 61.4
Yield, vol %: 54.0
Density at 15° C., kg/cu m (IP 190): 1,058.2
Sulfur, wt %: 7.38
Viscosity at 50° C., sq mm/sec (extrapo-lated): 85,000
Viscosity at 60° C., sq mm/sec (extrapo-lated): 27,000
Viscosity at 80° C., sq mm/sec: 4,190
Viscosity at 100° C., sq mm/sec: 919.5
Viscosity at 120° C., sq mm/sec: 310
Viscosity at 150° C., sq mm/sec: 85
Penetration at 25° C.: 304
Softening point, °C.: 33.9
Pour point, °C.: +42
Wax content, wt %: 5.0
Total nitrogen, mg/kg: 3,045
Acidity, mg KOH/g: 0.32
Microcarbon residue, wt %: 22.2
Asphaltenes, wt %: 15.9
Vanadium, mg/kg: 55
Nickel, mg/kg: 60

Boiling range, °C.: 500+
Yield, wt %: 43.3
Yield, vol %: 36.6
Density at 15° C., kg/cu m (IP 190): 1,101.4
Sulfur, wt %: 8.32
Viscosity at 80° C., sq mm/sec: no flow
Viscosity at 100° C., sq mm/sec: no flow
Penetration at 25° C.: 8
Softening point, °C.: 85.5
Total nitrogen, mg/kg: 4,195
Microcarbon residue, wt %: 32.0
Asphaltenes, wt %: 23.3
Vanadium, mg/kg: 80
Nickel, mg/kg: 85

Dewaxed oil