reservoir engineering.pdf
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PETE 301
RESERVOIR ENGINEERING
Ibrahim Kocabas Petroleum Engineering Department
King Fahd University of Petroleum & Minerals
Reservoir Engineering
Learning Objectives of Lecture 1:
n Define/describe a reservoir n Define Reservoir Engineering n Describe/list role/functions of Res. Eng. n State objectives of Res. Eng. n Pet. Res. Hyrdrocarbon (HC) fluids n Classification based on phase diagram n Types/forms reservoir energies
Reservoir Engineering
Branches of Petroleum Engineering: Drilling engineering Production engineering Reservoir engineering.
Definition of a Reservoir
A reservoir is that portion of a trap which contains oil and/or gas as a single hydraulically connected system.
-it is a rock layer -porous so that stores oil -permeable so that allows flow of oil -has a mechanism to prevent escape of
oil(trapping mechanism)
How many reservoirs?
What are the trapping mechanisms?
DEFINITIONs OF RESERVOIR ENGINEERING Craft “The application of scientific
principles to the drainage problems arising during the development and production of oil and gas reservoirs“.
DEFINITIONs OF RESERVOIR ENGINEERING Colhoun “The phase of engineering
which deals with the transfer of fluids to, from or through the reservoirs“.
Functions OF RESERVOIR ENGINEERING
To continuously monitor the reservoir and collect relevant data and interpret it to be able to
1. Determine (present conditions)) 2. Estimate ( future conditions) and 3. Control the movement of fluids through the
reservoir so that
Objectives of reservoir engineering
we can a) enhance ( increase recovery factor)
and b) accelerate ( increase production
rate) the oil recovery
Petroleum reservoir HC fluids
n Oil Reservoirs - Produce mainly oil and gas and in some cases also water
- Heavy oil - Conventional oil
- Black oil - Volatile oil
n Gas Reservoirs - Produce mainly gas and in some cases also water
- Dry gas - Wet gas
n Gas Condensate Reservoirs - Produce gas which contains hydrocarbon liquid
- Gas condensate
PHASE DIAGRAM OF RESERVOIR FLUIDS
Phase Diagram of Black Oil
Phase Diagram of Dry Gas
Phase Diagram of Wet Gas
Phase Diagram of Gas Condensate
CLASIFICATION OF OIL RESERVOIRS
n Under Saturated Oil Reservoirs - Reservoir pressure is initially above
the bubble point pressure n Saturated Oil Reservoirs - Reservoirs pressure is initially below
the bubble point pressure
STAGES OF OIL RECOVERY
Recovery (production): is the displacement of oil and gas
towards the production wells and to the surface, and divided into: – Primary recovery – Secondary recovery – Enhanced oil recovery
STAGES OF OIL RECOVERY
Primary Recovery Production is accomplished through
the use of natural energy of the reservoir.
What is(are) form(s) of natural reservoir energy?
Types of reservoir energy
1. - Energy of compression of water and rock within the reservoir
2. - Energy of compression of oil within the reservoir
3. - Energy of compression of gas within the reservoir
4. - Energy of compression of water that are in adjacent or underlying aquifers
Types of reservoir energy
5. The gravitational energy that causes oil and gas to segregate within the reservoir
6. The surface energy manifesting itself in capillary pores
Types of reservoir energy
Note: n First four are potential energies
stored in compressed constituents.
n Equivalent to the potential energy stored in a spring.
n When converted to pressure-volume work, we can produce fluids.
Types of reservoir energy
Note: As mechanisms of energy release
are provided by drilling and operation of wells the reservoir pressure declines, fluid expands, flow is induced and hence fluids are produced.
Reservoirs classified based on dominant natural energy
Can we classify reservoirs based on dominant producing energy type?
- no consensus on the definitions and classifications.
Producing mechanisms based on dominant reservoir energy being released
Expansion drive Water drive Compaction drive
Imbibition drive Oil drive Gas drive partial full
Solution Gas drive Gas cap drive Gas drive
Segregating Nonsegregating
From Lake and Walsh
Producing mechanisms based on dominant reservoir energy being released
Common special
Depletion drive
Gas cap drive
imbibition compaction
Solution Gas drive
Full Partial
Segregating Nonsegregating
Water drive Combination drive
Formation drive I.Edge
II.Bottom I.Edge
II.Bottom
gravity
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