GUIDE TO WORLD CRUDES: BP issues NWS condensate assay
Early last year, BP—whose subsidiary BP Developments Australia Pty. Ltd. holds an interest in the North West Shelf (NWS) venture off Australia—released a crude oil assay of the condensate produced in the massive project.
NWS officially dates from the opening of its Karratha natural gas processing plant in 1984 when it began receiving natural gas via the 84-mile subsea pipeline from the North Rankin A platform.
Current participants in the venture's gas interests are BHP Billiton Petroleum (North West Shelf) Pty. Ltd., BP Developments Australia Pty. Ltd., Chevron Australian Pty. Ltd., Japan Australia LNG (MIMI) Pty. Ltd., Shell Development (Australia) Pty. Ltd., and Woodside Energy Ltd., which also operates all NWS facilities.
In May 2008, Woodside acquired Shell Development (Australia) Pty. Ltd.'s 16.67% interest in NWS oil (OGJ Online, Feb. 11, 2008). China National Offshore Oil Corp. is also part of the NWS venture but holds no interest in its infrastructure, according to Woodside.
North Rankin
The North Rankin A platform serves as the central hub of the project's offshore gas production system. The platform stands about 84 miles northwest of Karratha, in about 410 ft of water, combining drilling, production, utilities, and accommodations.
The platform produces gas and condensate from North Rankin and Perseus fields and as of 2012, Woodside says, has 29 production wells: 22 intersecting North Rankin field and 7 intersecting Perseus.
Production capacity on the platform can reach 51,000 tonnes/day (tpd) of gas and 5,400 tpd of condensate, with dry gas and condensate moving through a trunkline system to the Karratha gas plant.
In March 2008, the NWS venture approved $5 billion (Aus.) funding for North Rankin redevelopment, which will access additional recoverable reserves by recovering remaining low-pressure gas from North Rankin and Perseus gas fields, thus extending field life to around 2040, according to Woodside.
The project has installed a second platform, North Rankin B, that connects by two 328-ft bridges (photo) to North Rankin A (OGJ Online, Mar. 31, 2008). North Rankin B will start up this year. Woodside will operate both platforms as a single integrated facility known as the North Rankin hub.
Goodwyn platform
The Goodwyn A platform stands about 14 miles southwest of North Rankin A to handle condensate-rich production from Goodwyn field. The platform is designed for up to 30 production wells, including 5 reinjection wells, and handles production of up to 36,000 tpd of gas and 11,000 tpd of condensate.
Dry gas and condensate from Goodwyn area reservoirs and Echo/Yodel fields (which came on line in 2001; OGJ Online, Dec. 27, 2001) and Perseus satellite field move by an interfield pipeline then by trunkline to the Karratha gas plant. In 2007, says Woodside, production began from Perseus and Searipple wells by the Perseus-over-Goodwyn pipeline that connects these wells to Goodwyn A.
Angel, Ohka
NWS's newest offshore gas production platform is Angel, which stands in 262 ft of water nearly 75 miles northwest of Karratha. The remotely operated platform is tied into the first trunkline at North Rankin A by a nearly 30-mile subsea pipeline.
Three subsea wells produce back to Angel. Woodside says hydrocarbons are produced through one "dry export" processing unit with capacity of up to 22,200 tpd of gas and 50,000 b/d of condensate and processed by the Karratha gas plant (OGJ Online, Oct. 3, 2008).
In 2011, the Okha floating production, storage and offloading vessel (FPSO) replaced the Cossack Pioneer FPSO as part of the $1.8 billion (Aus.) NWS oil redevelopment project to support oil production from Cossack, Wanaea, Lambert, and Hermes (CWLH) fields.
In December 2011, NWS participants approved the $2.5 billion (Aus.) Greater Western Flank (GWF) Phase 1, expected to start up in early 2016. GWF Phase 1 will develop Goodwyn GH and Tidepole fields by a subsea tieback to Goodwyn A (OGJ Online, Feb. 15, 2012).
Woodside says the broader GWF area consists of 16 fields to the southwest of Goodwyn A and estimates it to hold up to 3 tcf of recoverable gas and 100 million bbl of recoverable condensate.
Whole crude
API gravity at 60/60° F.: 63.0
Density at 15º C., kg/l.: 0.7272
Mercaptan sulfur, wt %: 0.0004
Viscosity at 20º C., cst: 0.68
Viscosity at 30º C., cst: 0.62
Viscosity at 40º C., cst: 0.57
Viscosity at 50º C., cst: 0.53
Viscosity at 60º C., cst: 0.50
Viscosity at 100º C., cst: 0.40
Pour point, ºC.: –60
Total nitrogen, ppm (wt): 1
Basic nitrogen, ppm (wt): 1
Acidity, mg KOH/g: 0.016
Carbon residue, wt %: 0.0004
C3, wt %: 0.3
i-C4, wt %: 0.9
n-C4, wt %: 2.92
i-C5, wt %: 5.92
n-C5, wt %: 8.99
Pentanes to 95° C.
Yield on crude, wt %: 40.49
Yield on crude, vol %: 43.37
Density at 15º C., kg/l.: 0.6768
Mercaptan sulfur, wt %: 0.0003
Total nitrogen, ppm (wt): 0.01
Acidity, mg KOH/g: 0.017
Research octane number: 70.4
Paraffins, wt %: 73.1
Naphthenes, wt %: 26.0
Aromatics, wt %: 0.9
n-Paraffins, wt %: 33.4
95-175° C.
Yield on crude, wt %: 37.853
Yield on crude, vol %: 35.97
Density at 15º C., kg/l.: 0.7633
Sulfur, wt %: 0.001
Mercaptan sulfur, wt %: 0.0006
Total nitrogen, ppm (wt): 0.05
Acidity, mg KOH/g: 0.0071
Research octane number: 39.6
Paraffins, wt %: 38.8
Naphthenes, wt %: 46.6
Aromatics, wt %: 14.6
n-Paraffins, wt %: 21.2
Pentanes to 149° C.
Yield on crude, wt %: 70.439
Yield on crude, vol %: 72.05
Density at 15º C., kg/l.: 0.7093
Mercaptan sulfur, wt %: 0.0005
Total nitrogen, ppm (wt): 0.02
Acidity, mg KOH/g: 0.0035
Research octane number: 64.9
Paraffins, wt %: 57.7
Naphthenes, wt %: 36.2
Aromatics, wt %: 6.1
n-Paraffins, wt %: 28.1
149-232° C.
Yield on crude, wt %: 17.5
Yield on crude, vol %: 15.95
Density at 15º C., kg/l.: 0.7960
Sulfur, wt %: 0.001
Mercaptan sulfur, wt %: 0.0003
Viscosity at 40º C., cst: 1.10
Viscosity at 60º C., cst: 0.87
Total nitrogen, ppm (wt): 0.33
Acidity, mg KOH/g: 0.0166
Aromatics, vol %: 17.45
Smoke point, mm: 26
Freezing point, ºC.: –60
Cetane index
ASTM D4737-90: 38.0
Refractive index at 70º C.: 1.4201
Naphthalenes, vol %: 1.0
232-342° C.
Yield on crude, wt %: 7.099
Yield on crude, vol %: 6.09
Density at 15º C., kg/l.: 0.8456
Sulfur, wt %: 0.027
Mercaptan sulfur, wt %: 0.0003
Viscosity at 50º C., cst: 2.36
Viscosity at 100º C., cst: 1.22
Cloud point, ºC.: –13
Pour point, ºC.: –14
Wax, wt %: 3.9
Total nitrogen, ppm (wt): 7
Basic nitrogen, ppm (wt): 3
Acidity, mg KOH/g: 0.0468
Aromatics, vol %: 18.98
Smoke point, mm: 19
Freezing point, ºC.: –13
Cetane index
ASTM D4737-90: 48.3
Refractive index at 70º C.: 1.4442
Aromatics, wt %: 21.7
Naphthalenes, vol %: 5.8
342-369° C.
Yield on crude, wt %: 0.401
Yield on crude, vol %: 0.33
Density at 15º C., kg/l.: 0.8725
Sulfur, wt %: 0.098
Viscosity at 50º C., cst: 7.1
Viscosity at 100º C., cst: 2.59
Cloud point, ºC.: 11
Pour point, ºC.: 10
Wax, wt %: 11.9
Total nitrogen, ppm (wt): 48
Basic nitrogen, ppm (wt): 22
Acidity, mg KOH/g: 0.0988
Aniline point, vol %: 86.4
Cetane index
ASTM D4737-90: 63.8
Refractive index at 70º C.: 1.462
369-509º C.
Yield on crude, wt %: 0.408
Yield on crude, vol %: 0.34
Density at 15º C., kg/l.: 0.8802
Sulfur, wt %: 0.107
Viscosity at 60º C., cst: 10.4
Viscosity at 100º C., cst: 4.07
Pour point, ºC.: 22
Wax, wt %: 13.2
Total nitrogen, ppm (wt): 169
Basic nitrogen, ppm (wt): 81
Acidity, mg KOH/g: 0.132
Carbon residue, wt %: 0.0389
Asphaltenes, wt %: 0.0015
Aniline point, vol %: 93.6
Refractive index at 70º C.: 1.4702
509-550º C.
Yield on crude, wt %: 0.003
Density at 15º C., kg/l.: 0.9233
Sulfur, wt %: 0.165
Viscosity at 60º C., cst: 83.6
Viscosity at 100º C., cst: 16.5
Wax, wt %: 11.3
Total nitrogen, ppm (wt): 482
Basic nitrogen, ppm (wt): 472
Acidity, mg KOH/g: 0.184
Carbon residue, wt %: 3.79
Asphaltenes, wt %: 0.257
Aniline point, vol %: 106.8
Refractive index at 70º C.: 1.493
550-585º C.
Yield on crude, wt %: 0.001
Density at 15º C., kg/l.: 0.9423
Sulfur, wt %: 0.19
Viscosity at 60º C., cst: 222.0
Viscosity at 100º C., cst: 31.10
Wax, wt %: 9.7
Total nitrogen, ppm (wt): 805
Basic nitrogen, ppm (wt): 665
Acidity, mg KOH/g: 0.179
Carbon residue, wt %: 8.01
Asphaltenes, wt %: 0.719
Aniline point, vol %: 109.4
