Table 4. Headspace Gas Concentrations in Gas Hydrated Cores on the Nigerian Continental Slopea.

Sample ID

Methane (ppm)

Ethane (ppm)

Propane (ppm)

i-Butane

(ppm)

n-Butane (ppm)

C1/

(C2+C3)

N-074C3
6,250
108
8.7
2.7
1.4
54

N-074C4

35,700

116

6.0

0.7

0.2

292

N-082C3

29,600

12

3.4

0.3

0.3

1,920

N-138C2

75,100

11

0.4

0.0

0.4

6,590

N-138C3

69,800

5.6

0.5

0.0

1.5

11,400

N-138C6

77,000

6.6

0.4

0.0

0.0

11,000

PEF005

37,600

17.2

1.2

0.3

0.2

1,990

PEF013

36,000

94.3

23.8

1.5

0.3

300

PT028a

16,400

5.2

0.9

0.7

0.5

2,250

PT028b

27,100

10.2

4.5

l.7

1.0

1,560

PEX005a b

5,470

41.6

4.4

0.9

0.2

116

NCG102 b

44,500

23.3

1.6

0.4

0.5

1,720

NGC103

106,000

79.1

2.1

0.9

0.4

1,280

NGC226 b

81,500

13.6

3.6

0.9

0.4

4,440

PCO005

423,000

101

3.1

2.1

2.1

3,910

PTX004

50,200

68.3

2.3

0.1

0.1

709

PTX017

62,800

19.3

2.4

0.2

0.2

2,840

PTX026 c

1,240,000

3,340

2,080

738

125

198

PAG008

35,900

21.8

37.0

9.9

7.1

474

PAG013

59,700

55.7

3.3

5.2

0.9

917

a - Unless otherwise noted, concentrations are the average of three headspace cans distributed in the bottom half of the core generally at (1) the bottom, (2) bottom minus 1-meter, and (3) near the middle of the core.

b - Concentration represents the can from the bottom of the core.

c - The reason the headspace volume is over 100% methane is that the can was over-pressurized. This one sample is not the averaged, but the concentration in the bottom can taken from this core.

2001 TDI-Brooks International, Inc.
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