Dro/4 Production Chemistry Division

Report No. ENV02/99

DRO/4 PRODUCTION CHEMISTRY DIVISION

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BELAIT – 4

GAS / WATER / SOIL

ANALYTICAL REPORT

MARCH 1999

Sampling Team / Ang S.L / Ahmad / Bohari / Ramblee / Samsuddin
Analyst / Isiah / Chiew / Hassan / Hazliana

Our own analyses interpretations or opinions expressed represent the best judgement of DRO/4 Production Chemistry Division. This document is confidential. Neither the whole nor any part of this document may be discussed to any third party without the prior written consent of DRO/4 Production Chemistry.

Introduction

Eighteen Belait wells have been drilled in the Labi area between 1912 and 1988. Belait 4 was initially drilled on 1-June-1914 to a depth of 1490 ft. In November 1914 work was abandoned after derrick and casing troubles. Drilling resumed in April 1915 to a depth of 2132 ft.

The gas production began from the well in April 1924 and stopped in April 1929 , the casing apparantly collapsed or rotten away.

Background

An environmental survey on the chemical parameters in Belait-4 was carried out in February 1999. The well was found to produce gas which bubbles through a small pool of water at its base and the water from the well is released to the Telingan river.

Two gas and water samples were taken from the well site respectively. H2S measurements were also directly taken to the bubbling water at the base of the conductor of the well. Soil samples were collected at different points from the well. Water samples were also taken from the waterfalls on the upstream and downstream of the river to check any likely contamination from the discharged water.

Methodology

Sampling -

Gas samples were collected by water displacement inside 150ml glass bottles.
Water samples from the well were taken by using a hand pump sampler.
Soil samples were taken one foot from the surface by a hand power tool auger.

Analysis -

Gas composition was determined by using a Gas Chromatograhy unit.
H2S measurement was detected by a hand pump drager tube.

Water

API RP-45
ASTM D3921
Hach
Inductive Couple Plasma , ICP

Soil

Sittingbourne method
Drying
Wet Decomposition
Inductive Couple Plasma , ICP

Conclusion

1.Gas samples collected from the bubbling water contain a mixture of air and hydrocarbon mainly 25% by volume of methane , C1.

Hydrogen sulphide measured near the conductor was 9 ppm but likely to be diluted at the open atmosphere.

Total hydrocarbons content in water released from the well was measured at 24 ppm but the values were decreasing at the points of waterfalls.

No major hydrocarbons contamination has been found in all the soil samples. Total Petroleum Hydrocarbons (TPH) measured in soil samples at three differents points were <1% by weight thus land treatment is not required.

LABORATORY ANALYTICAL REPORTS

I. Belait-4 Gas Analysis

Sampling Location / Bubbling water at the base of BL-4 conductor
Sampling Date / 13-02-99
Sampling Time / 1156 hrs
Gas Composition / unit / Run #1 / Run #2 / Average
Carbon Dioxide ( CO2) / %vol / 1.50 / 1.35 / 1.43
Nitrogen ( N2) / %vol / 58.46 / 58.60 / 58.53
Oxygen ( O2) / %vol / 15.12 / 15.06 / 15.09
Methane ( C1) / %vol / 24.80 / 24.86 / 24.83
Ethane ( C2) / %vol / 0.12 / 0.13 / 0.12
H2S (g) / ppm / 9 / 9 / 9

II.Belait-4 Soil Analysis

Sampling Point

/ /

Sample #1

Near casing /

Sample #2

0.5m from casing /

Sample #3

5m from casing

Sampling Date

/ /

13-02-99

Sampling Time , hrs

/ /

1124

1155

1200

Analysis

/ / / /

Total Petroleum Hydrocarbons

mg/kg

7154

5479

Liquid Content

% wt

68.3

64.9

40.7

/ /

5.2

4.7

4.1

Barium , Ba

mg/kg

14.4

19.3

3.4

III. Belait-4 Water Analysis

i. Analysis - A

Sampling Point

/ /

Casing

Tubing

Waterfall #01

Waterfall #02

Waterfall #03

Sampling Date

/ /

13-02-99

Sampling Time , hrs

/ /

1150

1155

1030

1110

1230

Analysis

/ / / / / /

/ /

7.3

8.1

7.7

6.9

4.8

Carbonate, CO3

mg/l

Nil

Bicarbonate, HCO3

mg/l

436.2

2205.8

46.4

68.3

11.6

Chloride, Cl

mg/l

*192.3

**355.0

230.8

301.8

177.5

Sulphate, SO4

mg/l

7.5

20.0

50.0

10.0

15.0

Calcium, Ca

mg/l

75.8

20.2

9.9

13.1

7.0

Magnesium, Mg

mg/l

29.3

12.5

18.3

20.8

17.2

Sodium & Potassium , Na

( calc.) /

mg/l

150.4

992.9

123.4

171.9

86.0

Total Petroleum Hydrocarbons

ppmv

24.0

17.0

4.0

2.6

7.4

Resistivity @ 21 °C

ohm-m

18.5

3.1

95.0

120.0

185.0

Total Dissolved Solids , CaCO3

/ mg/l / 215.0 / 1350.0 / - / - / -
Remarks : The resistivity test has been repeated and the results are confirmed.
* Repeated readings : 177.5 mg/l and 159.75 mg/l
** Repeated readings : 319.5 mg/l and 337.25 mg/l

ii. Analysis - B

Sampling Point

/ /

Casing

Tubing

Waterfall #01

Waterfall #02

Waterfall #03

Sampling Date

/ /

13-02-99

Sampling Time , hrs

/ /

1150

1155

1030

1110

1230

Analysis

/ / / / / /

Salinity

mg/l

300

1600

<100

Barium

mg/l

0.09

0.10

0.01

Water samples taken at the waterfalls.

waterfall #01 waterfall #02

Waterfall #03

Water sample taken from the tubing.

Gas bubbling through the water inside the outer casing where gas and water samples were taken.

Water displacement technique was used to collect a gas sample.

Map showing the route to Belait-4