Chevron Texaco assays Doba crude

The Doba blend is a combination of crudes from the Miandoum and Kome oil fields (Fig. 1). The project was on target to achieve full production in first quarter 2004 (OGJ, Feb. 23, 2004, p. 8)

The operator, Esso Exporation & Production Chad Inc., reported that the first oil shipped through the 1,070-km pipeline from southern Chad arrived at Kribi in September 2003 (OGJ Online, Oct. 13, 2003).

Doba blend crude was initially only oil from the Miandoum field; production from the Kome field started in first quarter 2004. ChevronTexaco expects that total production will reach 225,000 b/d in second quarter 2004.

The Doba blend will eventually include crude from the Bolobo field.

Fig. 2 shows a true boiling point curve for the whole crude. These data are from ExxonMobil Corp., which conducted an assay independent of ChevronTexaco's assay. Other data from the two assays were similar.

The project is jointly owned by:

• Esso Exploration & Production Chad Inc., a subsidiary of ExxonMobil, 40%.
• Petronas Carigali Sdn. Bhd., 35%.
• ChevronTexaco, 25%.

Whole crude

Gravity, °API: 20.5

Specific gravity: 0.9308

Sulfur, wt %: 0.16

Nitrogen, ppm: 2,190

Hydrogen, wt %: 12.1

Viscosity at 40° C., cst: 360

Viscosity at 50° C., cst: 185

Viscosity at 100° C., cst: 21.0

Viscosity at 135° C., cst: 8.34

Pour point, °C.: –4

Total acid number, mg KOH/g: 4.1

Characterization factor (K factor): 12.0

Molecular weight: 471

Gross heating value,

MMbtu/bbl: 6.24

Heptane asphaltines, wt %: 0.2

Microcarbon residue, wt %: 5.9

Ramsbottom carbon, wt %: 5.6

Vanadium, ppm: 0

Nickel, ppm: 9

Iron, ppm: 58

This floating storage and offloading vessel, stationed permanently off of Cameroon, holds the Chadian crude oil for arriving tankers. Photo courtesy of Esso Chad Inc.

Naphthas

Boiling range, °C.: 10-80

Yield, wt %: 0.1

Yield, vol %: 0.1

Gravity, °API: 75.2

Specific gravity: 0.6847

Sulfur, wt %: 0.00

Mercaptan sulfur, ppm: 5

Nitrogen, ppm: 0

Hydrogen, wt %: 15.8

Viscosity at 40° C., cst: 0.664

Viscosity at 50° C., cst: 0.595

Viscosity at 100° C., cst: 0.388

Viscosity at 135° C., cst: 0.314

Freeze point, °C.: –122

Pour point, °C.: –131

Smoke point, mm: 23

Aniline point, °C.: 54

Total acid number, mg KOH/g: 0.0

Diesel index: 98

Characterization factor (K factor): 12.4

RON, clear: 73.8

MON, clear: 69.5

Paraffins, vol %: 69.3

Naphthenes, vol %: 30.7

Aromatics, vol %: 0.0

Molecular weight: 100

Gross heating value, MMbtu/bbl: 4.96

Boiling range, °C.: 80-150

Yield, wt %: 0.9

Yield, vol %: 1.1

Gravity, °API: 48.9

Specific gravity: 0.7842

Sulfur, wt %: 0.00

Mercaptan sulfur, ppm: 10

Nitrogen, ppm: 0

Hydrogen, wt %: 14.5

Viscosity at 40° C., cst: 0.799

Viscosity at 50° C., cst: 0.711

Viscosity at 100° C., cst: 0.455

Viscosity at 135° C., cst: 0.365

Freeze point, °C.: –118

Pour point, °C.: –124

Smoke point, mm: 21

Aniline point, °C.: 49

Total acid number, mg KOH/g: 0.0

Diesel index: 59

Characterization factor (K factor): 11.5

RON, clear: 62.6

MON, clear: 61.6

Paraffins, vol %: 22.0

Naphthenes, vol %: 75.1

Aromatics, vol %: 2.8

Molecular weight: 120

Gross heating value, MMbtu/bbl: 5.49

Boiling range, °C.: 150-200

Yield, wt %: 1.1

Yield, vol %: 1.2

Gravity, °API: 38.7

Specific gravity: 0.8315

Sulfur, wt %: 0.01

Mercaptan sulfur, ppm: 6

Nitrogen, ppm: 1

Hydrogen, wt %: 13.3

Viscosity at 40° C., cst: 1.42

Viscosity at 50° C., cst: 1.23

Viscosity at 100° C., cst: 0.700

Viscosity at 135° C., cst: 0.532

Freeze point, °C.: –102

Pour point, °C.: –109

Smoke point, mm: 18

Aniline point, °C.: 46

Total acid number, mg KOH/g: 0.1

Cetane index: 26

Diesel index: 45

Characterization factor (K factor): 11.3

Paraffins, vol %: 17.7

Naphthenes, vol %: 61.9

Aromatics, vol %: 20.4

Molecular weight: 143

Gross heating value, MMbtu/bbl: 5.73

Kerosine

Boiling range, °C.: 200-260

Yield, wt %: 4.1

Yield, vol %: 4.4

Gravity, °API: 31.0

Specific gravity: 0.8708

Sulfur, wt %: 0.01

Mercaptan sulfur, ppm: 4

Nitrogen, ppm: 3

Hydrogen, wt %: 13.0

Viscosity at 40° C., cst: 2.63

Viscosity at 50° C., cst: 2.18

Viscosity at 100° C., cst: 1.07

Viscosity at 135° C., cst: 0.767

Freeze point, °C.: –83

Pour point, °C.: –91

Smoke point, mm: 15

Aniline point, °C.: 51

Total acid number, mg KOH/g: 0.2

Cetane index: 32

Diesel index: 38

Characterization factor (K factor): 11.2

Paraffins, vol %: 13.2

Naphthenes, vol %: 67.0

Aromatics, vol %: 19.8

Molecular weight: 168

Gross heating value, MMbtu/bbl: 5.92

Gas oils

Boiling range, °C.: 260-340

Yield, wt %: 11.8

Yield, vol %: 12.1

Gravity, °API: 25.1

Specific gravity: 0.9037

Sulfur, wt %: 0.08

Mercaptan sulfur, ppm: 1

Nitrogen, ppm: 75

Hydrogen, wt %: 12.7

Viscosity at 40° C., cst: 7.48

Viscosity at 50° C., cst: 5.62

Viscosity at 100° C., cst: 2.02

Viscosity at 135° C., cst: 1.26

Freeze point, °C.: –45

Pour point, °C.: –54

Smoke point, mm: 11

Aniline point, °C.: 59

Total acid number, mg KOH/g: 0.2

Cetane index: 37

Diesel index: 35

Characterization factor (K factor): 11.2

Paraffins, vol %: 10.9

Naphthenes, vol %: 56.9

Aromatics, vol %: 32.2

Molecular weight: 215

Gross heating value, MMbtu/bbl: 6.08

Boiling range, °C.: 340-450

Yield, wt %: 21.0

Yield, vol %: 21.1

Gravity, °API: 21.9

Specific gravity: 0.9227

Sulfur, wt %: 0.15

Mercaptan sulfur, ppm: 1

Nitrogen, ppm: 556

Hydrogen, wt %: 12.4

Viscosity at 40° C., cst: 51.5

Viscosity at 50° C., cst: 31.2

Viscosity at 100° C., cst: 5.82

Viscosity at 135° C., cst: 2.85

Freeze point, °C.: –8

Pour point, °C.: –14

Aniline point, °C.: 79

Total acid number, mg KOH/g: 2.7

Diesel index: 38

Characterization factor (K factor): 11.5

Paraffins, vol %: 4.7

Naphthenes, vol %: 52.7

Aromatics, vol %: 42.7

Molecular weight: 307

Gross heating value, MMbtu/bbl: 6.18

Boiling range, °C.: 450-570

Yield, wt %: 20.9

Yield, vol %: 21.0

Gravity, °API: 21.2

Specific gravity: 0.9264

Sulfur, wt %: 0.15

Mercaptan sulfur, ppm: 0

Nitrogen, ppm: 1,347

Hydrogen, wt %: 12.1

Viscosity at 40° C., cst: 288

Viscosity at 50° C., cst: 148

Viscosity at 100° C., cst: 16.9

Viscosity at 135° C., cst: 6.91

Pour point, °C.: 6

Aniline point, °C.: 98

Total acid number, mg KOH/g: 6.6

Diesel index: 44

Characterization factor (K factor): 12.1

Molecular weight: 479

Gross heating value, MMbtu/bbl: 6.23

Resids

Boiling range, °C.: 570+

Yield, wt %: 40.2

Yield, vol %: 39.0

Gravity, °API: 15.8

Specific gravity: 0.9605

Sulfur, wt %: 0.22

Nitrogen, ppm: 4,432

Hydrogen, wt %: 11.4

Viscosity at 40° C., cst: 28,766

Viscosity at 50° C., cst: 10,800

Viscosity at 100° C., cst: 467

Viscosity at 135° C., cst: 115

Pour point, °C.: 32

Characterization factor (K factor): 12.2

Molecular weight: 984

Gross heating value, MMbtu/bbl: 6.38

Boiling range, °C.: 340+

Yield, wt %: 82.1

Yield, vol %: 81.1

Gravity, °API: 18.7

Specific gravity: 0.9418

Sulfur, wt %: 0.18

Nitrogen, ppm: 2,658

Hydrogen, wt %: 11.9

Viscosity at 40° C., cst: 1,074

Viscosity at 50° C., cst: 505

Viscosity at 100° C., cst: 44.1

Viscosity at 135° C., cst: 15.5

Pour point, °C.: 9

Characterization factor (K factor): 12.0

Molecular weight: 568

Gross heating value, MMbtu/bbl: 6.29