artificial lift 1.0

Selection of artificial lift type

S. Raja Rajeshwary

LECTURE CONTENTS

1. Introduction and selection criteria

2. Review on artificial lift technique

3. Selection of artificial lift criteria

4. Rod pumps, electric submersible pumps,

hydraulic pumps, progressive cavity pumps,

gas lift

5. Well performance analysis2

Introduction and selection criteria

Artificial lift - Any method used to raise oil to the surface

through a well after reservoir pressure has declined to

the point at which the well no longer produces by means

of natural energy.

It may prove necessary from the beginning of production

for oil wells when the reservoir does not have enough

energy to lift the fluid to the surface process facilities or

when the productivity index is deemed inadequate.

The most common of artificial lift are: rod pumps,

electrical submersible pumps, hydraulic pumps,

progressive cavity pumps, Gas Lift. 3

ARTIFICIAL LIFT METHODS

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Gas Lift

ESP’s

PC Pumps

Hydraulic Pumps

Rod pump

6500

6000

5500

5000

4500

4000

0 3000 6000 9000 12000 15000

Outflow

Flow Rate ( STB/day )

Pw

f, ps

i

Reservoir InflowPerformance

INITIAL PRODUCTION PERFORMANCE

NATURAL FLOW

ARTIFICIAL LIFT ASSISTED PRODUCTION

6500

6000

5500

5000

4500

4000

0 3000 6000 9000 12000 15000

Outflow


Pw

f, ps

i


NOT FLOWING

FINAL PRODUCTION PERFORMANCE


6500

6000

5500

5000

4500

4000

0 3000 6000 9000 12000 15000

Outflow


Pw

f, ps

i


BACK TO PRODUCTION BY ARTIFICIAL LIFT


Review on artificial lift techniqueThe most popular forms of artificial lift are illustrated in the figure below.

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The most popular types of artificial lift

Review on artificial lift technique

Rod Pump – A downhole plunger is moved up and down by a rod connected

to an engine at the surface. The plunger movement displaces produced fluid

into the tubing via a pump consisting of suitably arranged traveling and

standing valves mounted within a pump barrel.

Electric Submersible Pump (ESP) – employs a downhole centrifugal pump

driven by a three phase, electric motor supplied with electric power via a

cable run from the surface penetrates the wellhead and is strapped to the

outside of the tubing.9

Review on artificial lift technique

10

Hydraulic Pump uses a high pressure power fluid to:

Drive a down-hole turbine or positive displacement pump

(or)

Flow through a venturi or jet, creating a low pressure

area which produces an increased drawdown and inflow

from the reservoir.

• Progressing Cavity Pump (PCP) – employs a helical, metal

rotor rotating inside an elastomeric, double helical stator. The

rotating action is supplied by down-hole electric motor or by

rotating rods.

Selection of artificial lift criteria

Factors influencing the preferred form of artificial lift –

Well and Reservoir Characteristics

Field Location

Operational Problems

Economics

Implementation on Artificial Lift Selection Techniques

Long Term Reservoir Performance and Facility Constraints

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Advantages of artificial lift methods


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Disadvantages of artificial lift methods

Rod Pumps

The first type of artificial lift introduced to oil field; most widely used for the following reasons Low cost

Mechanical simplicity

Easy installation and operation

Rod pumps can lift o moderate volumes (1000 bfpd) from shallow depths (7,000 ft)

o Small volumes (200 bfpd) from greater depths (14,000 ft)14

Rod Pumps

The surface equipment for a rod pump is illustrated in the following figure.

Prime mover – electric motor or gas engine, 600 rpm and reduces the speed to 20 strokes per minute (spm) or less.

Polished rod and sucker rods – connection between pumping unit and downhole pump.

Polished rod moves up and down through a stuffing box which seals against the polished rod and prevents surface leaks.

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Pumping Unit

Rod Pumps

16The surface equipment for a rod pump

Fig.3

Rod PumpsPump

• located near perforations at the bottom of the sucker rods string

• consists of a hollow plunger with circular sealing rings mounted on the outside circumference

• moves inside a pump barrel which is either inserted into the tubing or is part of the tubing

Standing Valve – mounted at the bottom of pump barrel

Traveling Valve – installed at the top of plunger

Standing and Traveling valves contain a ball which closes the passage in the plunger and the pump inlet.

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Rod Pumps

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Rod pump operation

Electric submersible pumps

-Electric submersible pumps are used as an

artificial lift method to produce from 150 to

60,000 bpd.

-Effective and economical means of lifting

large volumes from great depths

-Performs at highest efficiency when

pumping liquid only

-Operating life expected 1 to 3 years

-Motor and pump rotates at 2,900 rpm for 50

Hz power

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ESP completion designs with gas anchors

to aid gas separation in the casing

Vertical arrangement of gas anchors:

-makes separation of gas from liquid

-makes liquid entering into the bottom of pump


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ASSIGNMENT Compare and contrast the following artificial

methods in terms of (a) taking space, (b) handling capability of viscous oil, (c) requirement of power source, (d) maintenance and (e) operational procedures

1. Rod pumping 2. ESP(Electrical Submersible Pump)

3. GL(Gas Lift) 4. PCP(progressing Cavity Pump) 5. Hydraulic Pumping