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UBIT GAS LIFT LINE SIZEVALIDATION REPORT

This report gives a description of the Line size validation study carried out for the UBIT

GAS LIFT pipeline/piping system. The objective of the study was to validate the

pipeline/piping sizes proposed by the CLIENT, for the lines enlisted below;

i. Proposed 4 line to connect from boarding gas lift pipeline to gas lift manifold.

ii.Proposed 4 gas lift manifold at Ubit GA

iii. Proposed 2 gas lift flowlines for each of the Six (6) new candidate wells

iv. Proposed 6 production flowline from each of the six (6) new candidate

wells

v. Proposed 6 Test manifold

vi. Proposed 10 Production manifold

vii. Existing 4 Test manifold

All lines were sized in accordance to the requirements as stipulated in API RP 14E for single

phase gas & two (2) phase streams. The pressure drop and velocity criteria were employed

in the validation of all lines. For gas lines, the velocity of the stream must not exceed 60 ft/s

to avoid noise while pressure drop should be such that the outlet pressure can meet the

pressure requirement of the downstream equipment.

Two (2) phase lines were sized on the basis of their erosional velocity which serves

as the basis for determining the minimum cross sectional area of pipeline/piping required to

transport the fluid.

Summary of Results

I. 4 Boarding Gas Lift Pipeline (GN)

The table below shows a summary of the results obtained from the validation

calculations performed for the Boarding Gas Lift Pipeline.

Flow rate Pipe Size Schedule No. Fluid Velocity Pressure Drop (psi/100ft)

9 MMSCFD 4 XXS 8.8 ft/s 0.57

15 MMSCFD 4 XXS 14.7 ft/s 1.59

The 4 pipe size met the velocity criteria for both flow rates although at a flow rate of 9

MMSCFD, a velocity of 8.8 ft/s might give rise to liquid settle out in low spots. Hence, a

4 pipe size would be adequate to handle the flow rate. The pressure drop obtained is

also less than 10% of the inlet pressure.

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II. 4 Gas Lift Manifold

The table below shows a summary of the results obtained from the validation

calculations performed for the Gas Lift Manifold.

Flow rate Pipe Size Schedule No. Fluid Velocity Pressure Drop (psi/100ft)

9 MMSCFD 4 XXS 11.7 ft/s 0.76

15 MMSCFD 4 XXS 19.54 ft/s 2.11

The 4 pipe size met the velocity criteria for both flow rates. Hence, a 4 pipe size would

be adequate to handle the flow rate. The pressure drop obtained is also less than 10%

of the inlet pressure which makes it adequate.

III. 2 Gas Lift Flow lines

The table below shows a summary of the results obtained from the validation

calculations performed for the Gas Lift Manifold.

Flow rate Pipe Size Schedule No. Fluid Velocity Pressure Drop (psi/100ft)2 MMSCFD 2 XXS 11.46 ft/s 1.52

The 2 pipe size met the velocity criteria for the new gas lift flow lines. Hence, a 2 pipe

size would be adequate to handle the flow rate. The pressure drop obtained is also less

than 10% of the inlet pressure which makes it adequate.

IV. 6 Production Flowline for each candidate well

The table below shows a summary of the results obtained from the validation

calculations performed for the Gas Lift Manifold.

Gas Flow

rate

Liquid

Flow

rate

Pipe

Size

Schedule

No.

Erosional

Velocity

Minimum

Area (in2)

Minimum

inside

diameter (in)

5.65

MMSCFD

6512

BLPD6 120 40.76 ft/s 14.65 4.32

The 6 production flowline gave rise to an erosional velocity of 40.76. For this erosional

velocity, a minimum pipe inside diameter of 4.32 in is required. A 6 SCH 120 piping is

adequate for the flow rate since it provides a greater inside diameter as well as sufficient

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pressure containment since its MAWP at operating conditions is greater than the SITP of

the well it is producing from.

V. 6 Test Header

The table below shows a summary of the results obtained from the validation

calculations performed for the Test Header.

Gas Flow

rate

Liquid

Flow

rate

Pipe

Size

Schedule

No.

Erosional

Velocity

Minimum

Area (in2)

Minimum

inside

diameter (in)5.65

MMSCFD

6512

BLPD6 120 40.76 ft/s 14.65 4.32

The 6 Test Header gave rise to an erosional velocity of 40.76. For this erosional

velocity, a minimum pipe inside diameter of 4.32 in is required. A 6 SCH 120 piping is

adequate for the flow rate since it provides a greater inside diameter as well as sufficient

pressure containment since its MAWP at operating conditions is greater than the SITP of

the well it is producing from.

VI. 10 Production Manifold

The table below shows a summary of the results obtained from the validation

calculations performed for the Gas Lift Manifold.

Gas

Flow

rate

Liquid

Flow

rate

Pipe

Size

Schedule

No.

Erosional

Velocity

Minimum

Area (in2)

Minimum

inside

diameter (in)22.56

BLPD

26006

BLPD10 120 40.81 ft/s 58.55 8.63

The 6 production flowline gave rise to an erosional velocity of 40.81. For this erosional

velocity, a minimum pipe inside diameter of 8.63 in is required. A 10 SCH 120 piping is

adequate for the flow rate since it provides a greater inside diameter as well as sufficientpressure containment since its MAWP at operating conditions is greater than the SITP of

the well it is producing from.

VII. 4 Test Header

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If the existing test header is to handle the single well flow of 6512 BLPD as well as 5.65

MMSCFD for 2 phase flow, it would require a minimum inside pipe diameter of 4.32 in.

Hence, if a 4 SCH 120 is required for the test header, the corresponding inside diameter

would be less than that required (4.32 in). This implies that the existing 4 test header is

inadequate to handle the 2 phase flow rates since it gives rise to a higher erosional

velocity.