UNIVERSITI TEKNOLOGI PETRONAS
PCB4113 PCB4113 Enhanced Oil Recovery (EOR)
JAN 2015 Dr. Mohamm Mohammed ed Abdalla Abdalla Ayoub Ayoub Introduction to EOR Processes Section 1-1
Class Outlines Lea Le arn rnin ing g Ob Obje ject ctiv ives es an and d ou outc tcom omes es At the end of this class, students should be able to:
1. Get fami familiar liarize ized d with with EOR Process Processes. es. 2. Underst Understand and the the general general rules for each each EOR EOR methods. methods. 3. Underst Understand and the key differe differences nces between between IOR/W IOR/WF F and EOR. EOR.
4. Get aware aware abou aboutt the the used used termin terminolog ologies. ies.
Future Energy Consumption
Oil: transportation Coal: china and India growth Gas: Electra and heating
i. ii.
actual supply and demand, and partly by expectations
*As of 5/1/2015
Shale oil and shale gas potential •
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Enhanced oil recovery processes include all methods that use external sources of energy and/or materials to recover oil that cannot be produced economically by conventional means.
These recovery processes can be broadly classified as given in the following: •
steam flooding, hot water flooding, and insitu combustion.
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chemical flood, miscible flood, and gas drive.
The natural driving mechanisms of primary recovery are outlined as follows: Rock and liquid expansion drive Depletion drive Gas cap drive Water drive Gravity drainage drive Combination drive The most common primary oil recovery factors range from 20% and 40%, with an average around 34%,while the remainder of hydrocarbon is left behind in the reservoir.
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Secondary hydrocarbon (oil and/or gas) involves the introduction of artificial energy into the reservoir via one wellbore and production of oil and/or gas from another wellbore.
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Usually secondary recovery include the immiscible processes of waterflooding and gas injection or gaswater combination floods, known as water alternating gas injection (WAG), where slugs of water and gas are injected sequentially.
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Simultaneous injection of water and gas (SWAG) is also practiced, however the most common fluid injected is water because of its availability, low cost, and high specific gravity which facilitates injection.
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is implemented by injecting water into a set of wells while producing from the surrounding wells.
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Waterflooding projects are generally implemented to accomplish any of the following objectives or a combination of them: Reservoir pressure maintenance.
Dispose of brine water and/or produced formation water. As a water drive to displace oil from the injector wells to the producer wells.
Reasons for the success of waterflooding include the following: •
Water is an efficient agent for displacing oil of light to medium gravity.
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Water is relatively easy to inject into oilbearing formations.
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Water is generally available and inexpensive.
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Waterflooding involves relatively lower capital investment and operating costs, leading to favorable economics
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Waterflooding is generally implemented by following various types of well flooding arrangements such as:
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pattern flooding, peripheral flooding, and crestal flooding, among others.
In this figure, Waterflood operation was initiated using an inverted 9-spot pattern that was gradually transformed to a regular 5-spot pattern at later stages of waterflooding through well conversion and infill drilling Modifications of the injector/producer pattern and well spacing over the life of a waterflooding project to optimize the recovery of oil: (a) Early stage and (b) Late stage (Satter et al., 2008).
The injector wells are placed down dip to take advantage of gravity segregation, thus the injected water either enters the aquifer or enters near the aquiferreservoir interface.
Anticlinal reservoir The injected water either enters the aquifer or is near the aquiferreservoir interface displacing oil towards the producer wells located at the upper part of the reservoir.
Lesson Outcomes (
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To explain the principles of immiscible and miscible fluid displacement.
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To better describe the fluid Movement in Waterflooded Reservoirs, the displacement mechanism are to be explained.
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To introduce fundamental concepts of EOR processes using simple mathematical models that retain important features of more complex models.
To describe the frontal-advance theory (Buckley Leverett).
To understand the mathematical relationships that relate Welge analysis approach and recovery calculations.
To apply the concepts on immiscible water drive and gas cycling operations.
To understand factors to consider in Waterflooding
Immiscible Displacement water displacing oil or gas displaces oil. Objective: to understand the mechanisms rather than blindly using the ‘black box’. •
Revision of these properties: rock wettability, capillary pressure, relative permeability, mobility and mobility ratio, fluid displacement.
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efficiency, volumetric displacement efficiency, and total recovery efficiency.
Useful texts; G. Paul Willhite
Don W. Green &
Introduction Drive
mechanisms are means of providing energy to
move hydrocarbon from reservoirs. There
are drive mechanisms that involve the immiscible
displacement of oil “Immiscible displacement ”
means that there is no mixing
of injected and displaced phases at the pore level (through mass transfer of components)
Introduction •
Natural water drive gives highest recovery factor therefore water drive by injection is the most common method of secondary recovery.
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Nowadays, water drive system is modelled using numerical reservoir simulation to understand its displacement behavior and the recovery of oil.
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We want to understand the important properties and analytical techniques used to predict behavior of immiscible displacement process.
