PET305 Oil Production

PET305

Petroleum Production Engineering

Lay-out of Production System

PET305 Production

• What is the role of production engineers ?

3

Roles of Production Engineering

Petroleum production engineers to monitor production operations.

They design equipment and processes to achieve the maximum

profitable recovery of oil and gas.

They develop and use various enhanced recovery methods.

These include injecting water, chemicals, gases, or steam into an oil

reservoir to force out more of the oil, or fracturing to connect a

larger area of a reservoir to a single well.

Production engineers focus on production challenges, identifying,

testing, and implementing methods for improving oil and gas

production.

They might focus on economics, helping a team determine the

optimum number of wells appropriate for a given operation.

Perforations

Packer Casing

Casing head

Tubing head

Casing valve

Master valve

Tee

Pressure gauge Wing valve

Choke

Components of a Typical Producing

Well

To production equipment

Tubing

Main parts

of

Wellhead

assembly

Wing valve

Choke assembly

Dual master valves

Casing head

Braden head

Casing strings Tubing

Tubing hanger

Tubing head

Master valve

Wellhead components

Stops fluid flow,

shutting in well

Casing valve

Wing valve

Controls

production

line

To production equipment

Pressure gauges

Choke

Wellhead components

Tee

To production equipment

Production

• Flowing Wells – Pwf > oil column Pressure

• Production Tubing

• The Well Head • Casing Heads, Tubing Head, Christmas Tree

• List of Factors Affecting Production

• Skin & Productivity Index • Wellbore Damage; +Ve Skin factor

• Acidizing : negative Skin factor

9

Production

• Production Tubing

– Steel Pipe run with

Production Packer

• The Well Head – Casing Heads, of different

diameters (20”,13 3/8th”,7”)

– Tubing Head,

– Christmas Tree

– Production choke

valve

10

Wing valve

Choke assembly

Dual master valves

Casing head

Braden head

Casing strings Tubing

Tubing hanger

Tubing head

11

Cross-section for typical producing well

Production considerations • Initial Production

– Perforation

– TCP (tubing / casing pressure)

– Wireline Perforation

– Down Hole Pressure & Flow

12

Production

• Factors Affecting Production

– Reservoir Fluid Properties

– Porosity & Permeability

– Rock/Fluid Properties (Sw. Pc; wettability … etc)

– Production Design Criteria

– Production History

13

Production

Factors Affecting Production cntd,

• Skin

– Wellbore Damage – Positive

– Acidizing –Negative

– Productivity Index (PI) , STB/Day/PSI

14

Production

Acidizing –

Negative S

15

16

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Formation damage

Skin & (Darcy’s Equation)

S. Steady state radial flow

Artificial Lift

• Non- Flowing Wells

– Pwf < Hydrocarbon Column Pressure

• Artificial Lift Systems

– Beam Pumping

– Gas Lift

– Submersible Pumps

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Walking Beam Rod Pumping Unit

20

Artificial Lift

• Gas Lift

– Gas Lift Assembly

– Annular – Tubing Pressure

Differential

– Create “Artificial Flowing Well”

– Injection Gas Recirculate

– 6 STB/Day – 80,000 STB/day

21

22

Gas Lift

Artificial Lift

• Submersible Pumps

– Attached to Tubing

– Electric/Hydraulic

– Continuous/Intermittent

– Frequent Maintenance Issues

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Electric Submersible Pump

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ESP, electric

submersible pump,

consists of downhole

equipment,

Pump

Intake

Motor

Cable

Equalizer

…plus

...

Electric Submersible Pump

25

Electric Submersible Pump

26

…some of the most important

pieces of the system are above

ground: HVAC

supply

VSD/Control

panel

Junction

box Wellhead

Transformer

440-660v 440-660v

1000-

5000v

1000-

5000v

PET305 Production- outflow Pressure losses

PET305 Production system

Well

Reservoir

Surface

equipment

Inflow & outflow

Production Pressure losses – outflow

Example on pressure heads

A well with total depth of 10,000 ft. and 4600 psi

reservoir pressure (initial) Well Gas cut flowing oil= 5 lb/gal

Calculate; pressure gradient for gas cut oil

the DP (pressure Drop)

In outflow oil well: What are the other Pressure Drop

(back Pressure ); List them

Production Pressure losses –

outflow Now, What can be done to improve the out flow rate?

Friction pressure drop in production tubing

Chock pressure losses

Production Pressure losses –

outflow Now, What can be done to improve the out flow rate?

• Gradient of the fluid: Gas LIFT

•Flowing friction pressure drop: Larger tubing or lower

friction pressure

•Choke: why is a choke needed? Is it needed here? Test it!

Production Pressure losses –

outflow Potential energy pressure drop

For example

If oil density is 53 lb/ft3. for a well of 1000 ft vertical depth then

DP = 0.433 x (53/62.4) x 1000 = 367.7 psi

Production – pressure losses Pressure friction losses –

outflow

Production – pressure losses Pressure friction losses –

outflow

Then it has been modified by Chen in 1979 to

Production Pressure friction losses –

outflow

Production Pressure losses –

outflow For laminar flow

Production Pressure losses – friction in tubing –

outflow

NRe = 2100 the begin of transition flow

Production Pressure losses – friction in tubing –

outflow

Water density = 65.5 lb/ft3

Tubing diameter = 2 7/8 inches

f = 0.0063

Production Pressure losses – friction in tubing –

outflow

f = 0.0063

u in ft/s

D in ft

Density lb/ft3

L in ft

Surface Production

Facilities

Separators

41

Separation &

Treatment

Prod.

from

Wells

Gas

Oil

Water

Contaminants

Production Process

Schematic

Foam

emulsion

salt content

scale

corrosion

paraffin – wax

sand content

liquid carry over

Factors for design

Drop size

Retention time

Re-entrainment

Separation - sizing

The separator types

Vertical

Horizontal

Spherical

Two-phase separator

Three phase separator

Horizontal three phase separator

Other designs for Three phase separator

spherical separator

Two phase vertical separator

Double-drum separator for gas condensate

production