Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Introduction

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Importance of Reservoir Fluids Properties
Sour
Oil
Sour Gas
Wellhead
Reservoir
pR
pwf
pwh
Tubing
Chiller
Separator
NGL
Gas to Pipeline
Work
Delivery
Compressor
Gas
Heat
Load
Flowline
Heat Load
Gas Cooler
Gas
Sweetening
Gas
Dehydration
Oily water
Amin
Solvent
Glycol
Solvent
Gas Gas
Oil
Sweetening
Stripping
Gas Oil
Heat Load
Oil Heater Dehydrator Desalter
Fresh Water
Oil
Oil Oil
Water Treatment
Oil to Export
Water Disposal
Separator

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Hydrocarbon Formation and Migration
The exact origin of petroleum is not known, but scientific opinion is in favor of origin from the transformation of
organic material to hydrocarbon. These organic materials were deposited with mud in subsurface of the seas and
formed together the source rocks.
In the universe, the hydrocarbons are also found. Huge amount of frozen hydrocarbon are found in tale of
comets and in the atmosphere of planets.
There are two theories:
 Endogenous theory
 Exogenous theory

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Petroleum Reservoir Structure
Source Rock : Shales
Reservoir Rocks: Carbonates
(dolomite – Limestone) and
Sandstones
Base Rocks: Shales , Evaporates
and other impermeable rocks

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Petroleum Formation and Migration

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
The State of Hydrocarbons
 Gaseous state - hydrocarbons in gaseous state are referred to as
natural gas
 Liquid State – hydrocarbons occurring as liquids are known as
Oil or crude oil
 Solid (semisolid) state – solid deposits are known as tars and
asphalts

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical Composition of Petroleum
1 - The Paraffin series (Alkanes) – this series is characterized by the fact that:
 the carbon atoms are arranged in open chains (not a ring)
 the carbon atoms are joined by a single bond
 These hydrocarbons are said to be saturated since they contain all the
hydrogen possible.
2
2 
n
n H
C
Isomerism -
 normal Butane (nC4)
 Isobutane (iC4)
Under SC :
• C1 to C4 are in gaseous state
• C5 to C17 are in liquid state
• from C18 exists as wax-like solids

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical and physical properties of the paraffins
 The amount of paraffins in different petroleum is not constant.
 They are very stable (inert) components and are changed during
the time
 From C1 to C4 of this series are gases under SC (60 F and 14.7
psia). From C5 to C17 are liquids and from C18+ are colorless
waxlike solids.
Chemical Composition of Petroleum

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical Composition of Petroleum
2 – Unsaturated Hydrocarbons – These Type of hydrocarbon exists with double or
triple bonds between carbons. These hydrocarbons can add more hydrogen under
appropriate conditions and are considered as under-saturated hydrocarbons.
 Olefin series – olefin series of
hydrocarbons is characterized by
the fact that one bond in the
molecule is double. The simplest
is ETHYLENE , then PROPYLENE,
BUTYLENE
 Diolefins Series –These type of
unsaturated hydrocarbons have two
double bonds in the molecule.
BUTADIENE-1,3 and BUTADEINE 1,2
have the formula:
n
nH
C 2 2
2 
n
nH
C
 Acetylene Series –the acetylene
series have considerable
importance. These components
have a triple bond. The first
member is ACETYLENE
2
2 
n
nH
C

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical and physical properties of the unsaturated hydrocarbons
 Unsaturated hydrocarbons are very reactive. They react very rapid with chlorine to
form oily liquids.
 Under proper conditions they react with hydrogen and form corresponding
paraffin.
 Due to high reactivity they are not found in crude oil
 They are formed in large amounts in petroleum cracking processes and have
considerable industrial importance.
Chemical Composition of Petroleum

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical Composition of Petroleum
3 – The Naphthene Hydrocarbons (Cycloparaffins) – these hydrocarbons
are saturated in which the carbon chains form closed rings. The general
formula is: n
nH
C 2
The first member of this series is cyclopropane and has the following
structure: The carbon ring can
have side chains as
follow:
These components are saturated and very
stable. They are important constituent of
crude oil. Their chemical properties are
very similar to those of the paraffins

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Chemical Composition of Petroleum
4 – The Aromatic Hydrocarbons – these hydrocarbons are cyclic and
may be considered as derivatives of benzene. The structure of benzene
is as follow:
The aromatic hydrocarbons are either liquids or
solids under standard condition. Many of members
of this series are characterized by fragrant odor

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Non-hydrocarbon components or petroleum fluids
The non-Hydrocarbon components in crude oil may be small in Vol% (typically < 1%),
but their influence on quality of the produced crude oil is considerable.
Sulfur
Sulfur and its products are the most common impurity in crude oil, rating from 0.2 to
6% in some Mexican and Middle Eastern crude oils (the average is 0.65%).
Corrosive sulfur compounds:
• free sulfur
• hydrogen sulfide (H2S)
• mercaptans (ethyl mercaptans, C2H2SH), they are also formed during distillation
Crude Oil Composition

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Nitrogen
Nitrogen content of crude oil is typically < 01 wt%, but can be as high as 2%. They
can reduce the heating value of crude oil or natural gas
Oxygen
Oxygen compounds are present in some crude oils and decompose to from
naphthenic acid during distillation process. They can be very corrosive
Carbon dioxide
it is very common contaminant in hydrocarbon fluids. It is in gaseous phase
dissolved in water and crude oil
Crude Oil Composition
Non-hydrocarbon components or petroleum fluids

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Natural Gas
Natural gas is those part of hydrocarbon components which at a certain pressure
and temperature are in gas phase.
the composition of natural gas varies considerably from lean non-associated gas
to rich associated gas containing a significant intermediate components (C2 – C6) .
Associates Gas
Associated gas is produced from oil reservoirs. This gas is dissolved in oil or exists in
free gas phase. Associated gas is produced in association with oil.
Non-Associated Gas
Non-associated gas is produced from gas reservoirs. The gas reservoirs are classified as:
- Dry gas reservoirs
- gas-condensate reservoirs
- wet gas reservoirs
Terminology of Natural Gas

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Condensate
Condensate is those part of natural gas components which liquefies due to
change in operational condition (temperature and pressure)
Condensate
Gas + H2OVapor
Inlet condition:
1.0 MMMSCFD
2500 psia, 180 F
Wellhead
Slug catcher condition:
1000 psia, 75 F
Sea line
H2O liquid
Reservoir
pR
pwf
pwh
Tubing
Terminology of Natural Gas

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Natural Gas Liquids (NGL)
Natural gas liquids (NGL) is those part of natural gas components which
liquefies by a process such as refrigeration
NGL
Gas
Cold stream
Natural gas
Cooling
process
Terminology of Natural Gas

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
CNG is made by compressing natural gas (which is mainly composed of C1), to less
than 1% of the volume it occupies at standard atmospheric pressure. It is stored and
distributed in hard containers at a pressure of 200–248 bar (2900–3600 psi), usually
in cylindrical or spherical shapes.
CNG's volumetric energy density is estimated to be 42% of liquefied natural gas's,
and 25% of diesel's.
Compressed Natural Gas (CNG)
Terminology of Natural Gases

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Liquified Petroleum Gas (LPG)
Terminology of Natural Gases
• Liquefied petroleum gas (LPG) is mixture of C3 and C4 .
• The composition of LPG (ratio of C3 and C4) depends on intended use of the LPG and on the season
• LPG is generated as a by-product during crude oil refining and is also recovered from condensate,
NGL and LNG

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Liquified Natural Gas (LNG)
Terminology of Natural Gases
• Liquefied natural gas or LNG is Natural gas that has been converted
into liquid form for ease of transport and storage.
• LNG occupies only a very small fraction (1/600th) of the Volume of
natural gas and is therefore more economical to transport across
large distances. It can also be stored in large quantities that would be
impractical for storage as a gas.

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Gas to Liquids Process (GTL)
Terminology of Natural Gas
GTL has been available for long time but not economically justified
Shell has had a GTL plant in operation at Bintulu, Malaysia since 1993
One of leading companies in this arena is SASOL, which in partnership with
Chevron and Qatar Petroleum has brought a GTL plant in Qatar (Pearl GTL).
The Pearl GTL converts 1.6 MMMSCF per day of natural gas into 140 MSTB
of petroleum liquids (naphtha) and 120 MSTB of C2+.
Virtually any hydrocarbon can be synthesized form any other. The
key parameters are:
1. pressure
2. temperature
3. type of catalyst

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Adsorbed Natural Gas (ANG)
Terminology of Natural Gas
• The walls of the nano-porous carbon adsorb methane molecules
as a high-density fluid. The strong attractive force in the narrow
pores lowers the energy of the molecules so that they can be
packed much more closely than in the absence of the carbon.
Such a tank is called an adsorbed natural gas (ANG) tank.
• The target set by the US Department of Energy is 180 times the
storage a material’s own volume and is reached.

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Methane (C1)
Ethane (C2)
Propane (C3)
Butane (C4)
Pentane Plus (C5+)
Non-Hydrocarbons (water, CO2,
H2S, etc)
Natural
Gas NGL
Condensate
LNG
LPG
CNG
Terminology of Natural Gas

Introduction
Presented By: Aminshahidy B. Ph.D.
Petroleum Engineering Dept. – Ferdowsi University of Mashhad
Properties of Petroleum
Reservoir Fluids
Oil and Gas Research
Institute, FUM
Ferdowsi University of
Mashhad
Source : https://commons.wikimedia.org/wiki/File:NatGasProcessing.png
A Gas Treatment Facility