Transcript Introduction to Artificial Lift Methods

Advanced Artificial Lift Methods
Advanced Artificial Lift Methods – PE 571
Introduction
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Class Schedule
Instructor: Tan Nguyen
Class: Tuesday & Thursday
Time: 09:30 AM - 10:45 AM
Room: MSEC 367
Office: MSEC 372
Office Hours: Tuesday & Thursday 2:00 – 4:00 pm
Phone: ext-5483
E-mail: [email protected]
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
References
Brown, Kermit E. (1980). The Technology of Artificial Lift Methods, Volumes 1,
2a and 2b. Tulsa, OK: PennWell Publishing Co.
Brown, Kermit E. (1982). “Overview of Artificial Lift Systems.” Journal of
Petroleum Technology, Vol. 34, No. 10. Richardson, TX: Society of Petroleum
Engineers.
Clegg, J.D., Bucaram, S.M. and Hein, N.W. Jr. (1993). “Recommendations and
Comparisons for Selecting Artificial Lift Methods.” Journal of Petroleum
Technology (December), p. 1128. Richardson, TX: Society of Petroleum
Engineers.
Moineau, Rene (1930). “Un Nouveau Capsulisme.” Extracts from doctoral
thesis, University of Paris.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
References
Takács, Gabor (2005). Gas Lift Manual. Tulsa , OK : PennWell Publishing.
Weatherford International Ltd. (2003, 2005). Artificial Lift Products and
Services . Houston : Weatherford International Ltd.
Schmidt, Z. and Doty, D.R (1989): "System Analysis for Sucker-Rod Pumping."
SPE Production Engineering (May), p. 125. Richardson , TX : Society of
Petroleum Engineers.
Zaba, J., (1968), Modern Oil Well Pumping. Tulsa, OK: PennWell Publishing Co.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Course Outline
Chapter 1: Electrical Submersible Pump
Chapter 2: Rod Sucker Pump
Chapter 3: Gas Lift
Chapter 4: Plunger Lift
Chapter 5: Progressive Cavity Pump
Chapter 6: Hydraulic Pump
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Course Outline
Introduction to Artificial Lift Methods
Homework
15 %
Quizzes
20 %
Project
30 %
Final
35 %
Advanced Artificial Lift Methods
Introduction to Artificial Lift
IPR vs. OPR
q = PI × (Pavg - Pwf)
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Inflow Performance Relationship (IPR)
A well never actually attains its absolute flow potential, because in order for it to
flow, Pwf must exceed the backpressure that the producing fluid exerts on the
formation as it moves through the production system. This backpressure or
bottomhole pressure has the following components:
•
Hydrostatic pressure of the producing fluid column
•
Friction pressure caused by fluid movement through the tubing, wellhead and
surface equipment
•
Kinetic or potential losses due to diameter restrictions, pipe bends or
elevation changes.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Artificial Lift
Artificial lift is a means of overcoming bottomhole pressure so that a well can
produce at some desired rate, either by injecting gas into the producing fluid
column to reduce its hydrostatic pressure, or using a downhole pump to provide
additional lift pressure downhole.
We tend to associate artificial lift with mature, depleted fields, where Pavg has
declined such that the reservoir can no longer produce under its natural energy.
But these methods are also used in younger fields to increase production rates
and improve project economics.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Gas Lift
Gas lift involves injecting high-pressure gas from the
surface into the producing fluid column through one or
more subsurface valves set at predetermined depths
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Gas Lift
There are two main types of gas lift:
Continuous gas lift, where gas is injected in a constant, uninterrupted stream.
This lowers the overall density of the fluid column and reduces the hydrostatic
component of the flowing bottomhole pressure. This method is generally
applied to wells with high productivity indexes.
Intermittent gas lift, which is designed for lower-productivity wells. In this type
of gas lift installation, a volume of formation fluid accumulates inside the
production tubing. A high-pressure “slug” of gas is then injected below the
liquid, physically displacing it to the surface. As soon as the fluid is produced,
gas injection is interrupted, and the cycle of liquid accumulation-gas injectionliquid production is repeated.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Gas Lift
Advantages: Gas lift can be used in deviated or crooked wellbores, and in hightemperature environments that might adversely affect other lift methods, and it
is conducive to maximizing lift efficiency in high-GOR wells. Wirelineretrievable gas lift valves can be pulled and reinstalled without pulling the
tubing, making it relatively easy and economical to modify the design.
Disadvantages: the availability of gas and the costs for compression and
injection are major considerations. Lift efficiency can be reduced by corrosion
and paraffin. Another disadvantage of gas lift is its difficulty in fully depleting
low-pressure, low-productivity wells. Also, the start-and-stop nature of
intermittent gas lift may cause downhole pressure surges and lead to increased
sand production.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift
Downhole pumps are used to increase pressure at the bottom of the tubing
string by an amount sufficient to lift fluid to the surface. These pumps fall into
two basic categories: positive displacement pumps and dynamic displacement
pumps.
A positive displacement pump works by moving fluid from a suction chamber to
a discharge chamber. This basic operating principle applies to reciprocating
rod pumps, hydraulic piston pumps and progressive cavity pumps (PCPs).
A dynamic displacement pump works by causing fluid to move from inlet to
outlet under its own momentum, as is the case with a centrifugal pump.
Dynamic displacement pumps commonly used in artificial lift include electrical
submersible pumps (ESPs) and hydraulic jet pumps.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – Reciprocating Rod Pump
Beam pumping is the most common artificial lift
method. It can be used for a wide range of
production rates and operating conditions, and rod
pump systems are relatively simple to operate and
maintain. However, the volumetric efficiency
(capacity) of a rod pump is low. its initial
installation may involve relatively high capital
costs. Its application is very limited for deep,
inclined and horizontal wells.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – PCP
As the rotor turns, cavities between the rotor and
stator move upward.
Progressive cavity pumps are commonly used for
dewatering coalbed methane gas wells, for
production and injection applications in waterflood
projects and for producing heavy or high-solids oil.
They are versatile, generally very efficient, and
excellent for handling fluids with high solids
content. However, because of the torsional
stresses placed on rod strings and temperature
limitations on the stator elastomers, they are not
used in deeper wells.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – Hydraulic Pump
Hydraulic pump systems use a power fluid—
usually light oil or water—that is injected from the
surface to operate a downhole pump. Multiple
wells can be produced using a single surface
power fluid installation
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – Hydraulic Pump
With a reciprocating hydraulic pump, the injected power fluid operates a
downhole fluid engine, which drives a piston to pump formation fluid and spent
power fluid to the surface.
A jet pump is a type of hydraulic pump with no moving parts. Power fluid is
injected into the pump body and into a small-diameter nozzle, where it becomes a
low-pressure, high-velocity jet. Formation fluid mixes with the power fluid, and
then passes into an expanding-diameter diffuser. This reduces the velocity of the
fluid mixture, while causing its pressure to increase to a level that is sufficient to
lift it to the surface
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – Hydraulic Pump
Used at depths from 1000 to 17,000 feet and are capable of producing at rates
from 100 to 10,000 B/D. They can be hydraulically circulated in and out of the well,
thus eliminating the need for wireline or rig operations to replace pumps and
making this system adaptable to changing field conditions. Another advantage is
that heavy, viscous fluids are easier to lift after mixing with the lighter power fluid.
Disadvantages of hydraulic pump systems include the potential fire hazards if oil is
used as a power fluid, the difficulty in pumping produced fluids with high solids
content, the effects of gas on pump efficiency and the need for dual strings of
tubing on some installations.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – ESP
An electric submersible pumping (ESP)
assembly consists of a downhole centrifugal
pump driven by a submersible electric
motor, which is connected to a power
source at the surface
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – ESP
Advantages:
The most efficient lift methods on a cost-per-barrel basis.
High rate: 100 to 60,000 B/D, including high water-cut fluids.
Work in high-temperature wells (above 350°F) using high-temperature motors
and cables.
The pumps can be modified to lift corrosive fluids and sand.
ESP systems can be used in high-angle and horizontal wells if placed in
straight or vertical sections of the well.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Pump-Assisted Lift – ESP
Disadvantages:
ESP pumps can be damaged from “gas lock”. In wells producing high GOR
fluids, a downhole gas separator must be installed. Another disadvantage is
that ESP pumps have limited production ranges determined by the number and
type of pump stages; changing production rates requires either a pump change
or installation of a variable-speed surface drive. The tubing must be pulled for
pump repairs or replacement.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Selecting an Artificial Lift Method – Reservoir Characteristics
Artificial lift considerations should ideally be part of the well planning process.
Future lift requirements will be based on the overall reservoir exploitation
strategy, and will have a strong impact on the well design.
Some of the key factors that influence the selection of an artificial lift method.
IPR: A well’s inflow performance relationship defines its production potential
Liquid production rate: The anticipated production rate is a controlling factor
in selecting a lift method; positive displacement pumps are generally limited to
rates of 4000-6000 B/D.
Water cut: High water cuts require a lift method that can move large volumes
of fluid
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Selecting an Artificial Lift Method – Reservoir Characteristics
Gas-liquid ratio: A high GLR generally lowers the efficiency of pump-assisted lift
Viscosity: Viscosities less than 10 cp are generally not a factor in selecting a lift
method; high-viscosity fluids can cause difficulty, particularly in sucker rod
pumping
Formation volume factor: Ratio of reservoir volume to surface volume
determines how much total fluid must be lifted to achieve the desired surface
production rate
Reservoir drive mechanism: Depletion drive reservoirs: Late-stage production
may require pumping to produce low fluid volumes or injected water.
Water drive reservoirs : High water cuts may cause problems for lifting systems
Gas cap drive reservoirs : Increasing gas-liquid ratios may affect lift efficiency.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Selecting an Artificial Lift Method – Hole Characteristics
Well depth: The well depth dictates how much surface energy is needed to move
fluids to surface, and may place limits on sucker rods and other equipment.
Completion type: Completion and perforation skin factors affect inflow
performance.
Casing and tubing sizes: Small-diameter casing limits the production tubing size
and constrains multiple options. Small-diameter tubing will limit production rates,
but larger tubing may allow excessive fluid fallback.
Wellbore deviation: Highly deviated wells may limit applications of beam
pumping or PCP systems because of drag, compressive forces and potential for
rod and tubing wear.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Selecting an Artificial Lift Method – Surface Characteristics
Flow rates: Flow rates are governed by wellhead pressures and backpressures in
surface production equipment (i.e., separators, chokes and flowlines).
Fluid contaminants: Paraffin or salt can increase the backpressure on a well.
Power sources: The availability of electricity or natural gas governs the type of
artificial lift selected. Diesel, propane or other sources may also be considered.
Field location: In offshore fields, the availability of platform space and placement
of directional wells are primary considerations. In onshore fields, such factors as
noise limits, safety, environmental, pollution concerns, surface access and well
spacing must be considered.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
Selecting an Artificial Lift Method – Field Operating Characteristics
Long-range recovery plans: Field conditions may change over time.
Pressure maintenance operations: Water or gas injection may change the
artificial lift requirements for a field.
Enhanced oil recovery projects: EOR processes may change fluid properties
and require changes in the artificial lift system.
Field automation: If the surface control equipment will be electrically powered, an
electrically powered artificial lift system should be considered.
Availability of operating and service personnel and support services: Some
artificial lift systems are relatively low-maintenance; others require regular
monitoring and adjustment. Servicing requirements (e.g., workover rig versus
wireline unit) should be considered. Familiarity of field personnel with equipment
should also be taken into account.
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
General Guidelines (Weatherford 2005)
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
General Guidelines (Weatherford 2005)
Introduction to Artificial Lift Methods
Advanced Artificial Lift Methods
Introduction to Artificial Lift
General Guidelines (Weatherford 2005)
Introduction to Artificial Lift Methods