Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

Well Performance 11

DewPo

intLin

e

Bubb

lePo

intLin

e

Pre

ssur

e

Temperature

Liquid Phase Only

Gas Phase Only

100% Liquid

80%

60%

40%

20%

5% 0% Liquid

Critical Point

(d)

(c)

(b)

(a)(PR,TR)

(Pwf,Twf)

(Psep,Tsep)

Reservoir

Wellbore

(e)

Separator

Two PhaseRegion

(f) 0.025

0.050.040.03

0.020.015

0.010.0080.0060.004

0.002

0.0010.00080.00060.0004

0.00020.00010.00005

0.00001

0.02250.0200.0175

0.0150.0140.0130.0120.0110.0100.0090.0080.0070.00650.0060.00550.0050.00450.0040.0035

0.003

0.00250.002250.002

2 3 4 5 6 8

104

2 3 4 5 6 8

105

2 3 4 5 6 8

106

2 3 4 5 6 8

107

2 3 5 6 8

108

103

Reynolds Number, Re

Rel

ativ

e R

ough

ness

, e =

k/D

Fric

tion

Fac

tor,

f

Laminar Flow

f = 64/Re

0.0000050.000001

Transition zone to fully turbulent flow Complete turbulence

Rough pipe

Smooth pipe

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

22Selection of Ar tificial Lift Types

Rod

Pump

TubingAnchor

Power Fluid

HighPressure

PowerFluidProduction

Production Production

Production

Electric Motor

Gas FlowMeter

Gas Flow

ElectricPower Cable

PumpGas Lift Valve(unloading)

Operating Valve

Stator

Rod

Rod

Motor

Fluid DrivenPump

(i) Rod Pump (ii) Hydraulic Pump (iii) Submersible ElectricPump

(iv) Gas lift (v) Progressing Cavity Pump(May also be driven by

electric submersible motor)

Production

Gas Flow RateControl Valve

Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

33Gas Lift

Injected Gas(Control and Metering)

Produced Fluid and Injected Gas to Separator

Gas Lift Valves

(c) Large Gas Bubble Displaces Liquid Slug

(b) Gas BubbleExpands as

the Hydrostatic Pressure Reduces

(a) Injected Gas ReducesAverage Fluid Density

Gas Injected at"Operating Valve"

Producing Formation

Perforations

Liquid

Gas

(a) Reduction ofFluid Density

(b) Expansion of Gas

Bubbles

Liquid

Gas

(c) Displacement of

Liquid Slugsby Gas Bubbles

Liquid

Gas

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

Formation Damage 44

Ideal Pressure Profile(Undamaged)

Actual Pressure Profile(Damaged) (kd < k)Pd

Pd

P2

P3

Prkd k

rw rd re- Extra pressure drop due to Formation Damage

ReservoirDamaged

ZoneWellboreCentreline

0 2 4 6 8 10 12 14 16 18 20 22 24

1000

100

10

1

0.1

0.01

Radius of Damaged Zone Beyond Wellbore, ft

Pro

duct

ion

Rat

e, b

bl/d

ay

kd = 50md

kd = 10md

kd = 1md

Permeability of undamaged resrervoir = 100 mdFormation thickness 10ft.Wellbore radius 0.25ft. Drainage radius 500ft.Oil viscosity 0.5 cpDrawdown 536 psi

Effect of Formation Damage on Well Production

Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

Matrix Acidising 55In

suffi

cien

t HC

I

Con

cent

ratio

n H

F (

% W

t)

Concentration HCI (% Wt)

5

4

3

2

1

0

0 5 10 15 20 25

1.45

1.45

1.401.35

OptimumAcid Formations(10% wt HCl 0.7% wt HF)

Acidized Porosity < 35 %

35 % < < 40 %

> 40 %

Contours With Constant Production Increase (Q acid / Q original)

Composition of Rock

Quartz 74.9 % wtK-Feldspar 7.0 % wtIllite 6.0 % wtKaolinite 10.0 % wtDolomite 0.1 % wtAnhydrite 0.5 % wtAlbite 1.0 % wtSiderite 0.5 % wt

Porosity (%) : 20No Drilling Impairment

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

66Hydraulic Fracturing

(Soft) Formation Fracture Face

(Soft) Formation Fracture Face

Embedment in formation

Filter cake

Fracture closure stress

N.B. Proppant grain crushing and deformation not illustrated (see Fig 30)

Original propped width fracture

Effective fracture width for flow

Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

Unstable Formations andSand Control

77

yyyyyy

yyy

yyyyyy

yyyyyyyyy

yyyyyyyyyyyy

Screen

Screen

Cement

Strengthened Zone

Producing Interval

Producing Interval

Perforation

Packer

Gravel

Gravel

Casing

SANDCONSOLIDATION

INTERNALGRAVEL

PACK

EXTERNALGRAVEL

PACK

Producing Interval

"Frac Pack"

Vertical former (for strength)

Stainless steel wirein triangular shape

Gap kept constant

Key form allows anysand grain that passes narrowest point to be flushed from slot

Spot weld

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

Water Content of Hydrocarbon Gas

Temperature F

Wat

er C

onte

nt o

f Nat

ural

Gas

(lb

wat

er/m

illio

n cu

ft. o

f wet

gas

at 6

0 F

and

14.

7 ps

ia)

80000

60000

40000

20000

10000

8000

6000

4000

2000

1000

800

600

400

200

100

80

60

40

20

10

8

6

4

2

1

80000

60000

40000

20000

10000

8000

6000

4000

2000

1000

800

600

400

200

100

80

60

40

20

10

8

6

4

2

1

0.6

20 25 30 35 40 45 50

50 F100 F

150 F

200 F

250 F

300 F

0.8 1.0

1.0

0.9

0.8

0.71.2 1.4 1.6 1.8

Molecular Weight

Correction Factor for Gas Gravity

Gas Relative Density

CG

1.00

0.98

0.96

0.94

0.92

0.900 1 2 3 4

Total Solids in Brine. %

Cs

=

H20

Fro

m B

rine

H20

Fro

m W

ater

Correction Factor for Salinity

-60 -40 -20 0 20 40 60 80 100 120 140 160 180 200 240 280

HY

DR

AT

E F

OR

MA

TIO

N L

INE

14.7

psi

a25

50

100

200

300

400

500

600

1000

1500

2000

4000

5000

6000

1000

0

80003

000

800

14.7

psi

a25

50

100

200

300

400

500

600

1000

1500 2

000

800

Position of this lineis a function of gas composition

Water contents of natural gasses with corrections for salinity and relative density.After McKetta and Wehe, Hydrocarbon Processing. August 1958

Years

Pro

du

ctio

n

1 2 3 4 5 6 7 8

Plateau

Decline

First Gas

Dis

cove

ry

Operating Expenses (Gas Equivalent)

Abandonment

Annual Peak e.g. Winter in NW Europe

88Oil and Gas Processing

Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

Water Handling 99

Oil Froth Gas Injection

Perforated Hood

Rapid Rotation of Paddle Produces Small Gas Bubble

CleanWater OutletOily Water Inlet

Oil Outlet

Gas / Oil Bubbles

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

Oil and Gas Field Operations 101019

92

1993

1994

1995

1996

16.014.012.010.0

8.06.04.02.00.0M

illio

ns o

f Ton

nes

1992

1993

1994

1995

1996

0

50.0

100.0

150.0

Mill

ions

of T

onne

s

Ref. No. PT/2, Version 1.1 Date of issue 9 / 10 / 00

Exercise 1111

Riser / Mud Line

Seabed / Well Line

Top of Reservoir

OWC

SSV

MSL

ft.

RKB / Xmas Tree

Depthft. TVD-RKB

0

Figure 2 Haggis-3 Well Schematic

Ref. No.PT/2, Version 1.1 Date of issue 9 / 10 / 00

1212Examination and ModelSolutions

Answer to Q1Answer to Q1Answer to Q1Answer to Q1Answer to Q1

1(a) (Standard) 3-phase horizontal separator diagram.

Gas

Mist Eliminator

Oil Outlet andLevel Control

Water Outlet andLevel Control To Oil Export

To ProducedWater Treatment

Inlet

Inlet Deflector/ Momentum Breaker

Pressure Control Valve

OIL and EMULSION

WATER

GAS

PC

Weir

OIL

Main componentsMain componentsMain componentsMain componentsMain components Main functionMain functionMain functionMain functionMain function

Inlet momentum breaker => to reduce inlet flow velocity (hence

helping disengage free gas)

Mist eliminator/extractor => to remove liquid drops from gas

(by allowing liquid droplets to impinge

on the wire, coalesce and flow down in

to the liquid phase)

Weir => to separate oil and water phases (oil

is collected here and skimmed off

from main settling area)

Liquid outlets under level controls => to evacuate oil and water (usually

equipped with a vortex breaker to

prevent re-entrainment of gas)

yyyyyyyyyyyyyyyy

Date:

1. Complete the sections above but do not seal until the examination is finished.

2. Insert in box on right the numbers of the questions attempted.

3. Start each question on a new page.

4. Rough working should be confined to left hand pages.

5. This book must be handed in entire with the top corner sealed.

6. Additional books must bear the name of the candidate, be sealed and be affixed to the first book by means of a tag provided

Subject:

INSTRUCTIONS TO CANDIDATES

8 Pages

PLEASE READ EXAMINATION REGULATIONS ON BACK COVER

No. Mk.

NAM

E:REGISTRATION N

O.:

COURSE:

YEAR:

SIGNATURE:Complete this section but do not

seal until the examination

is finished