Oil and gas laboratory analysis and

tests

INTRODUCTION:

CRUDE OIL:

Chemical Composition.

Chemical and Physical

Characteristics.

Classifications of Oils.

Compatibility of Crude Oils.

Tests and Laboratory

apparatus:

Sampling.

Reservoir Surface Samples.

PVT TESTS.

Chemical Standard and

Specialized tests.

content

Refinery Distillates Tests:

Refinery Distillates.

Refinery Distillates General tests.

Refinery Distillates Special tests.

Natural Gas:

Composition

Refinery Gas

Natural gas processing

Uses of Natural Gas

Properties and Test Methods

Sampling

Calorific Value (Heat of

Combustion)Composition

Lube Oil Tests:

Lubrication Principles.

Lubrication and Lubricants

Lube Oil production.

Characteristics of Lube Oils.

Lube Oil Classifications.

Lubricating Additives.

Sudan Crude Oil

Specifications.

Oil in Sudan

Introduction

Oil industry in Sudan

Sudan Oil Blocks

Refining and Downstream

Crude Oil General Tests for

90/10 Nile / Thar Jath Blend

Fula Crude

PDOC Crude Oil Blend

Sudanese crude Oil properties

from test result

Statistics for Crude Oil &

Productions

1. INTRODUCTION

A qualitative or A quantitative

Analytical methods

yields information

about the atomic or

molecular species

or the functional

groups that exist in

the sample.

provides numerical

information as to

the relative amount

of one or more of

these components.

Classical or instrumental

Analytical methods

A- Classical Methods

1. Semimicro Qualitative Analysis

separation of the original mixture into several parts

Each part is then subjected to an analysis of a small

number of species. In summary, the analysis involves

a set of sequenced separations and identifications.

Ex.GROUPS SEPATATION

2. Gravimetric Analysis

the unknown is precipitated from solution by a

reagent and, after separation and drying, is weighed.

3. Titrimetric (Volumetric) Analysis

we obtain the volume of a standard reagent required

to consume an analyte completely.

INSTRUMENTAL

ANALYSIS

Separation Methods

Spectral Methods

Electroanalytical methods

B-Instrumental Methods

1- Classification of separation process

2. Spectral Methods:

Spectroscopy= study of the interaction of

electromagnetic radiation with matter.

When matter is energized (excited) by the

application of thermal, electrical, nuclear or

radiant energy, electromagnetic radiation is

often emitted as the matter relaxes back to its

original (ground) state.

• The spectrum of radiation emitted by a

substance that has absorbed energy is

called an emission spectrum and the

science is appropriately called emission

spectroscopy.

Electroanalytical methods:

• Electroanalytical methods are study an analyte by

measuring the potential (volts) and/or current (amperes)

in an electrochemical cell containing the analyte.

The three main categories are:

potentiometry (the difference in electrode potentials is

measured),

coulometry (the cell's current is measured over time),

voltammetry (the cell's current is measured while

actively altering the cell's potential).

SAMPLING

• The value of any product is

judged by the characteristics

of the sample as determined

by laboratory tests.

•The sample used for the test(s)

must be representative of the bulk material,

SAMPLING

• In addition, the type and

cleanliness of sample

containers are important:

• In addition, adequate records of

the circumstances and

conditions during sampling must

be made;

SAMPLING

• Solid samples require a different

protocol might involve melting

(liquefying) of the bulk material

(thermal decomposition is not

induced) followed by

homogenization.

• the protocol used for COKE sampling

(ASTM D-346, ASTM D-2013) that

are solid, for accurate analysis is

required before sale.

• Once the sampling procedure is accomplished, the sample container should

be labeled immediately to indicate the product:

• 1. The location, from which the sample was obtained.

• 2. The identification of the location by name.

• 3. The character of the bulk material (solid, liquid, or gas) at the time of

sampling.

• 4. The means by which the sample was obtained.

• 5. The protocols that were used to obtain the sample.

• 6. The date and the amount of sample that was originally placed into

storage.

• 7. Any chemical analyses that have been determined to date.

• 8. Any physical analyses that have been determined to date.

• 9. The analysts who carried out the work.

• 10. A log sheet showing the names of the persons (with the date and the

reason for the removal of an aliquot) who removed the samples from

storage and the amount of each sample (aliquot) that was removed for

testing.

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MEASUREMENT

The issues that face Petroleum analysts

include need to provide higher quality results.

In addition,

Follow the environmental regulations, may

influence the method of choice.

The method of choice depends on the boiling

range (or carbon number) of the sample to be

analyzed.

Each test has its own limits of accuracy and

precision that must be adhered to if the data

are to be accepted.

ACCURACY

• The accuracy of a test is a measure of

how close the test result will be to the

true value of the property being

measured.

As such, the accuracy can be expressed

as the bias between the test result and

the true value.

• The absolute accuracy can only be

established if the true value is known.

• Alternatively to approach that, we pick out

the essential tests in a specification from

the specification as a whole and extract the

essential features (termed principal

components analysis).

• Which involves an examination of set of data

as points in n-dimensional space

(corresponding to n original tests) and

determines (first) the direction that accounts

for the biggest variability in the data (first

principal component).

• The process is repeated until n principal

components are evaluated, but not all of

these are of practical importance because

some may be attributable purely to

experimental error.

• In the short term, selecting the best of the

existing tests to define product quality is the

most beneficial route to predictability.

PRECISION

The precision of a test method is the

variability between test results obtained on

the same material using the specific test

method.

The precision of an analytical method is the

amount of scatter in the results obtained from

multiple analyses of a homogeneous sample.

Precision is expressed as repeatability and

reproducibility.

• REPEATABILITY=The intralaboratory

precision or within-laboratory precision refers

to the precision of a test method when the

results are obtained by the same operator

in the same laboratory using the same

apparatus.

• In some cases, the precision is applied to

data gathered by a different operator in the

same laboratory using the same apparatus.

Thus intralaboratory precision has an

expanded meaning insofar as it can be

applied to laboratory precision.

• Reproducibility= The interlaboratory precision

or between-laboratory precision is defined in

terms of the variability between test results

obtained on the aliquots of the same

homogeneous material in different

laboratories using the same test method.

• The repeatability value and the reproducibility

value have important implications for quality.

METHOD VALIDATION

Method validation is the process of proving that an

analytical method is acceptable for its intended

purpose.

Many organizations, such as the ASTM, provide a

framework for performing such validations.

In general, methods for product specifications and

regulatory submission must include studies on

specificity, linearity, accuracy, precision, range,

detection limit, and quantitation limit.

The first step in the method development and validation cycle should be to set

minimum requirements, which are essentially acceptance specifications for the

method.

Once the validation studies are complete, the method developers should be

confident in the ability of the method to provide good quantitation in their own

laboratories.

2. CRUDE OIL

petroleum, oily, flammable fluid that

occurs naturally in deposits, usually

beneath the surface of the earth; it is

also called crude oil. It consists

principally of a mixture of

hydrocarbons, with some of various

nitrogenous sulfurous and

phosphorus compounds and traces

of heavy metals such as vanadium,

and nickel.

• that occur widely in the sedimentary

rocks in the form of gases, liquids,

semisolids, or solids.

• It is not known exactly when

humankind first used petroleum. It is

known, however, that ancient

peoples worshipped sacred fires that

were fuelled by natural gas seeping

to the surface through pores and

cracks.

FLUID DESTRIBUTION

CAP ROCKS

GAS = GAS CAP

GAS+SOME WATER

GAS +OIL

OIL + GAS

OIL

RESREVOIR ROCKS

OIL + WATER

WATER + OIL

WATER

OIL WELL

FLUID DESTRIBUTION CAP ROCKS

GAS

RESREVOIR ROCKS

GAS+ WATER

WATER + GAS

WATER

GAS WELL

• The exact molecular composition varies widely from

formation to formation but the proportion of chemical

elements vary over fairly narrow limits as follows:

Composition by weight.

• Element Percent range

• Carbon 83 to 87%

• Hydrogen 10 to 14%

• Nitrogen 0.1 to 2%

• Oxygen 0.05 to 1.5%

• Sulfur 0.05 to 6%

• Metals less than 1000 ppm

CHEMICAL COMPOSITION

CRUDE OIL

H.C.

SATURATED UNSATURATED

BASICS OF HYDROCARBON CHEMISTRY

HYDROCARBONS

SATURATED UNSATURATED

PARAFFINS OLEFINS

-Long Chain = normal ACETYLENS

-Cyclic = Naphthens AROMATICS

-Branched = Iso-

-Long Chain

-Cyclic

-Branched

-Long Chain

-Branched

-Branched

Composition of Crude Oil

CRUDE OIL

HYDROCARBONS NON-HYDROCARBONS

ALIPHATICS AROMATICS NAPHTHENES SULFURS NITROGENS OXYGENS METALLICS

25% 17% 50% <8% <1% <3% <100PPM

C1 - C60 (C6H5)n CYCLOALKANESSH

S

N

H

O

COOH

Crude Oil Classification

PETROLEUMSaturates

Aromatics

Asphalticsn-alkanes C5 - C44

branched alkanes

cycloalkanes (napthenes) single ring

condensed ring

nitrogen

oxygen

sulfur

containing compounds

Na pht he ne s

5 0 %

Ar oma t i c s

7 %

Aspha l t i c s

8 %

Ot he r

1 0 % S a t ur a t e s

2 5 %

API Gravity = 35o

The Xylenes

Boiling Point 144oC 139.3

oC 137-138

oC

Melting Point -25oC -47.4

oC 13-14

oC

ortho meta para

CH3

CH3

CH3

CH3

CH3

CH3

Composition by weight

Hydrocarbon Average Range

Paraffins 30% 15 to 60%

Naphthenes 49% 30 to 60%

Aromatics 15% 3 to 30%

Asphaltics 6% remainder

Four different types of hydrocarbon molecules appear in crude

oil.

The relative percentage of each varies from oil to oil, determining

the properties of each oil.

Non-hydrocarbons

Chemical and Physical Characteristics

The appearance of crude petroleum varies

From yellow low or green colored mobile liquid

to darker and often almost black syrupy fluids

and sometimes solidifying to a black paste,

this great variety in appearance is a obviously

caused by difference in composition .

Some oils may be particularly rich in

hydrocarbons with a low M. wt and others rich in

hydro carbons of complicated large molecules.

(1) Physical Properties of crude oil

Density : Mass per unit volume under specified conditions

of pressure and temperature, It is usually determined at

atmospheric pressure and at a temp of 15 ºC (60 ºF).

Specific Gravity : The ratio of the densities of a

substance and water under Specified conditions of

pressure and temperature and it's dimensionless

and at 60/60 ºF.

APIGravity : It refers to the API system and it has

empirical formula as follow :

141.5

ºAPI = 131.5 - ــــــــــــــــــــــــــــــــــــــــ

Sp. gr @ 60/60 ºF

CRUDE OIL CLASSIFICATION

ACCORDING TO API Gr.

• > 45 = Extra Light (Not Useful)

• 40 – 45 = Excellent (the highest

price)

• > 31.1 = Light

• 31.1 – 22.3 = Medium

• < 22.3 = Heavy

• < 10 Extra Heavy (Bitumen)

In physics, buoyancy is

the upward force that

keeps things afloat. The

net upward buoyancy

force is equal to the

magnitude of the weight of

fluid displaced by the

body. This force enables

the object to float or at

least seem lighter.

Buoyancy

density and specific gravity of crude oil

(ASTM D-71, ASTM D-287,

ASTM D-1217, ASTM D-1298,

ASTM D-1480, ASTM D-1481,

ASTM D-1555, ASTM D-1657,

ASTM D-4052,

IP 235, IP 160, IP 249,

IP 365)

are two properties that have found wide use

in the industry for Preliminary assessment of

the character of the crude oil.

Density and Relative Density (Specific

Gravity) of Viscous Materials by Lipkin

Bicapillary Pycnometer ASTM D-

1481

Density and Relative Density (Specific

Gravity) of Viscous Materials by

Bingham Pycnometer ASTM D-

1480

Density weighing bottle

Density, Relative Density (Specific Gravity), or API Gravity

of Crude Petroleum and Liquid Petroleum Products by

Hydrometer Method D 1298

This test method covers the laboratory determination

using a glass hydrometer, of the density, relative

density (specific gravity), or API gravity of crude

petroleum, petroleum products, or mixtures of

petroleum and nonpetroleum products normally

handled as liquids, and having a Reid vapor

pressure of 101.325 kPa (14.696 psi) or less.

Digital density meter with oscillating

U-tube installed

• The oscillating U-tube is a technique to

determine the density of liquids and gases

based on an electronic measurement of

the frequency of oscillation, from which

the density value is calculated. This

measuring principle is based on the Mass-

Spring Model.

In the digital density meter, the mechanic

oscillation of the U-tube is e.g.

electromagnetically transformed into an

alternating voltage of the same frequency. The

period τ can be measured with high resolution

and stands in simple relation to the density ρ of

the sample in the oscillator:

(B) Boiling point and Boiling Range:

• The difference in the boiling point of

individual hydrocarbons is the basis of the

dist, technique by which crude oil

fractionated into cuts of different volatility.

For all homologous series of hydrocarbons

the boiling point increases with the number

of carbon atom in the molecule. Aromatics

have, in general higher boiling point than

the corresponding apothems and paraffin's.

(C) Melting point:

• The crystatization of solid from a liquid oil

fraction seriously hampers its flow and may

give rise to blocking of lines and clogging of

filters, so melting point is very important from a

view point of oil processing and the application

of the product. The melting points of

homologues hydrocarbons increase with M.

wt. In general Iso paraffin have, in general, a

lower melting point than normal paraffins of

same number of carbon atom.

(D) Viscosity:

• Viscosity of an oil product is very important from a

technical point of view It is plays an important part in

calculation of pipelines and the design of furnaces and

heat exchangers and is further one of the leading

properties in lube oil and fuel oil and fuel oil prices are

frequently based on viscosity. Viscosity depends on the

type of components and temp. Viscosity of paraffins is

approximately a function of the density. Aromatics with a

low M .wt often have a lower viscosity than in the

corresponding paraffins, whereas the high molecular

aromatics of lube oil are more viscous than the paraffins.

Viscosity

VISCOSITY= It is a resistance of liquid layers to flow.

• F= Frictional force between two layers.

• S= Area of interface between two layers.

• dv/dx=Velocity gradient between two

layers.

F α S α dv/dx

F α S . dv/dx

F = η S . dv/dx

Viscosity coefficients(η)

• Viscosity coefficients can be defined in two

ways:

• Dynamic viscosity, also absolute

viscosity, the more usual one (typical

units Pa·s, Poise, P);

• Kinematic viscosity is the dynamic

viscosity divided by the density (typical

units cm2/s, Stokes, St).

η = Viscosity Coefficient

• The force per unit area, Vis. Dynes per

cm2, required to maintain unit difference of

velocity i.e 1 cm per Sec. between two

parrallel layers 1 cm apart.

• F = η . dv/dx

• So, if η is low Liq. Is Mobil and

• So, if η is high Liq. Is Viscous

• 1/η = φ FLUIDITY

• η= = X X F/S

dv/dx

dynes

cm2 cm/Sec

1 1/cm

1

η= Dynes cm-2 Sec = Poise “ P ”

1 cp= 10-2 P

• η= = X 1/ F/S

dv/dx

dynes

cm2

cm 1

X

Sec cm

Water at 20 °C has a viscosity of 1.0020 cP.

Kinematic viscosity • In many situations, we are concerned with the ratio of

the inertial force to the viscous force.

• This ratio is characterized by the kinematic viscosity ,

defined as follows:

• Ʋ=

• The SI unit of ν is m2/s. The SI unit of ρ is kg/m3.

• The cgs physical unit for kinematic viscosity is

the stokes (St). • It is sometimes expressed in terms

of centiStokes (cSt).

ƞ ρ

Stokes = Dynes cm-2 Sec / (g / cm3)

1 P= d X Stokes So, Stokes = P/ d

Stokes = cm2 / Sec

1 cSt= 10-2 St

Stokes = g cm Sec-2 .cm-2 Sec / (g / cm3)

1 St = 1 cm2·s−1 = 10−4 m2·s−1.

1 cSt = 1 mm2·s−1 = 10−6m2·s−1.

Water at 20 °C has a k. v. of about 1 cSt.

Cannon-Fenske Routine Viscometer

for Transparent Liquids

Zeitfuchs Cross-Arm Viscometers

for Transparent and Opaque

Liquids

(E) Solubility characteristics:

• The Solubility characteristics of the various hydrocarbons

types play an important part in the extraction processes like

extraction of aromatics which dissolve in polar solvent like

phenol much better than paraffins and naphthenes.

• Although the physical properties of petroleum and petroleum

products are often equated with those of the various related

hydrocarbons, the electrical and optical properties of pure

hydrocarbons have been investigated to a lesser degree

than the so-called typical physical properties, leaving

considerable gaps in knowledge. Thus very little is known

about the electrical and optical properties of crude oil.

(F) Electrical properties:

• The electrical properties of crude oil and

crude oil products (especially lubricating

oils) can be of considerable practical

significance.

• Electrical Conductivity: The electrical

conductivity of hydrocarbons is quite small. It is

generally recognized that hydrocarbons do not

usually have an electrical conductivity larger than

10-18 Ω/cm. Thus it is not surprising that the

electrical conductivity of crude oils or crude oil

fractions (ASTM D-3114, IP 274) is from 10-19

Ω/cm to 10-12 Ω/cm -. Available data indicate that

the observed conductivity is frequently more

dependent on the method of measurement and

the presence of trace impurities than on the

chemical type of the oil. Most oils increase in

conductivity with rising temperatures.

• Dielectric Strength: The dielectric strength, or

breakdown voltage (ASTM D-877; see also IP

295), is the greatest potential gradient or

potential that an insulator can withstand without

permitting an electric discharge. The property is,

in the case of oils as well as other dielectric

materials, somewhat dependent on the method

of measurement, that is, on the length of path

through which the breakdown occurs, the

composition, shape, and condition of the

electrode surfaces, and the duration of the

applied potential difference.

(G) OPTICAL PROPERTIES

• Color: The color test has lesser significance in the preliminary

inspection of the

black feedstock.

• Play an important role in determining the purity and/or the stability of

petroleum products,

• for example, tests for the acid or basic nature of petroleum products by

color titration (ASTM D-974, IP 139, 213, IP 431), the Doctor test for

sulfur species (ASTM D-4952), the color of aviation gasoline (ASTM D-

2392), the color of petroleum products using a color scale (ASTM D-

1500, IP 17, IP 196), and the color of petroleum products using the

Saybolt chromometer (ASTM D-156). In fact, the test for the color of

petroleum products (ASTM D-1500) can, if desired, be adapted to heavy

oil and bitumen by applying the test to specifically diluted solution of

heavy oil or bitumen in a colorless solvent such as toluene.

• Refractive Index: The refractive index (ASTM D-1218,

ASTM D-1747) is the ratio of the velocity of light in a

vacuum to the velocity of light in the substance.

• The refractive index can be used to give information

about the composition of hydrocarbon mixtures (ASTM

D-2140, ASTM E-1303, IP 346, IP 391, IP 436). As

with density, low values are typical of paraffins and

higher values are typical of aromatic compounds.

• The method (ASTM D-1218) covers the measurement

of the refractive index of liquid petroleum and

petroleum products in the range of 1.3300-1.6500.

Typically, the measurement is carried out at 20oC

(68°F).

• Optical Activity:

• Petroleum is usually dextrorotatory, that is,

the plane of polarized light is rotated to the

right, but there is known levorotatory crude

oils, that is, the plane of polarized light is

rotated to the left, and some crude oils have

been reported to be optically inactive.

• Optically active crude oils shows that the

rotatory power increases with molecular

weight (or boiling point) to pronounced

maxima and then decreases again.

(2) Chemical Properties of crude oil

It is very difficult to discuss the chemical reaction

in which various hydrocarbons can enter so, only a

few important groups of reactions will be

considered, namely:

Reaction under the influence of heat ( thermal

reactions pyrolysis )

Reaction under the influence of oxygen (

oxidation reactions )

• Thermal reactions: Thermal stability of

hydrocarbons decreases, in general, as M. wt

increase.

• Oxidation Reaction: Most pure paraffin's naphthenes

and Aromatic are not affected by oxygen under

atmospheric pressure and temp and therefore stable

in storage. It should be mentioned that olefins and

practically di-olefins are easily oxidized and converted

into polymers.

• Many so called " impurities " like nitrogen , oxygen

and Sulphur compounds occurring in relatively small

% in crude oil may give troubles when present in

certain product , especially when the product have

been aged during storage (oxidation).

Classification of Oils

• Classification as a Hydrocarbon Resource

• Classification by Chemical Composition

• To accommodate crude oils that were neither

paraffin base nor naphthene base, the term

intermediate base is applied.

Compatibility of Crude Oils.

• Petroleum fouling:

• Causes, Tools, and Mitigation methods

• With the high price of light crude oils most

refineries are driven to purchase greater quantities

of lower priced opportunity crudes that are

heavier and contain higher concentrations of sulfur

and of naphthenic acids.

• This has led to higher frequency of refinery

fouling, just when incentives for refinery

utilization and for energy conservation are at

their peak.

• Fortunately, the understanding of the causes

and mitigation methods of petroleum fouling

has greatly improved recently through the

development of tools for prediction and for

identification.

• Fouling is defined as the formation

of an unexpected phase that

interferes with processing.

• While the fouling phase is often a

solid, a liquid or it could be an

emulsion.

• Fouling make units need to be shut

down periodically for cleaning.

• Most only consider the maintenance cost of

cleaning. The insulating effect of layers of

foulant on heat exchange surfaces can cost

refineries large amounts of energy without it

being realized.

• foulants reduce the efficiency of fractionators

and reduce the reactivity in catalytic reactors.

Most will conclude that they need not wait for

a large fouling incident to justify a significant

program on fouling mitigation.

• Fouling Mitigation Strategy

• The best strategy to mitigate fouling is to

elucidate the foulant chemistry and to use this

basic knowledge to determine how and where

to eliminate its formation.

• Most Common Causes of refinery fouling

are:

• A. Organic

• B. Inorganic

• A. Organic Fouling during Crude Processing

• All organic fouling in the crude unit is due to

insoluble asphaltenes. There are three modes of

insoluble asphaltenes in crude oils:

• asphaltenes may be insoluble in the crude oil as

purchased (self-incompatible),

• the asphaltenes may precipitate when crude oils are

mixed (incompatible), and

• the asphaltenes may adsorb out of the crude oil onto

metal surfaces (nearly incompatible).

• The Oil Compatibility Model and Crude

Incompatibility • The oil compatibility model is a solubility parameter based model that enables one to

predict the compatibility or incompatibility of any mixture of any number of oils. This

is based upon testing the compatibility of the individual oils with different

proportions of a model solvent, such as toluene, and a model nonsolvent, such as n-

heptane. These tests enable measuring the solubility parameter of the mixture at

which asphaltenes just begin to precipitate. This solubility parameter on a reduced n-

heptane-toluene scale is called the insolubility number, IN. In addition, the tests

measure the solubility parameter of the oil that on a reduced n-heptane-toluene scale

is called the solubility blending number, SBN. An example -shown in Figure- where the

compatibility numbers are measured for the two crudes, Souedie and Forties, with

the minimum two tests each. One test, the heptane dilution test, involves determining

the maximum volume of n-heptane that can be added to a given volume of oilwithout

precipitating asphaltenes. Insoluble asphaltenes are most accurately detected by

observing a drop of the mixture between a glass slide and a cover slip under an

optical microscope at 100 to 200X.

3. TESTS AND LAB

APPARATUS

Sampling: Crude oil sampling in accordance with the international

sampling standards of ISO 3171, ASTM D 4177, API 8.2, IP

6.2, ASTM D 4057, ASTM D 5854 and ASTM D 5842.

• Samples:

• 1 all-levels sample—a sample obtained by submerging a stoppered

beaker or bottle to a point as near as possible to the draw-off level,

then opening the sampler and raising it at a rate such that it is

approximately three-fourths full as it emerges from the liquid.

• 2 bottom sample— a spot sample collected from the material at the

bottom of the tank, container, or line at its lowest point.

• 3 bottom water sample—a spot sample of free water taken from

beneath the petroleum contained in a ship or barge compartment or a

storage tank.

• 4 composite sample— a blend of spot samples mixed in proportion to

the volumes of material from which the spot samples were obtained.

• 5 drain sample— a sample obtained from the water draw-off valve on a

storage tank.

6 floating roof sample—a spot sample taken just below the

surface to determine the density of the liquid on which the

roof is floating.

7 flow proportional sample—a sample taken from a pipe

such that the rate of sampling is proportional throughout

the sampling period to the flow rate of the fluid in the pipe.

8 upper sample— a spot sample taken from the middle of

the upper one-third of the tank’s contents (a distance of

one-sixth of the liquid depth below the liquid’s surface).

9 middle sample— a spot sample taken from the middle

tank’s contents (a distance of one-half of the depth of liquid

below the liquid’s surface).

10 lower sample— a spot sample of liquid from the middle

of the lower one-third of the tank’s content (a distance of

five-sixths of the depth liquid below the liquid’s surface).

Reservoir Surface / Subsurface

Samples

From producing reservoirs, representative fluid

samples can usually be obtained at either

surface or subsurface locations.

surface samples are removed at either the

separator or at the wellhead, with the associated

gas and liquid subsequently recombined in

proportions to represent the actual reservoir fluid.

Subsurface samples are removed from within

the wellbore at actual reservoir conditions using

bottom hole sampling tools and techniques.

Equation of State Modelling

useful to evaluate the

quality of the surface samples

and provide a method of

recombining phases in order to

predict overall phase behavior at

reservoir conditions.

Example 1. A saturated oil reservoir

had an original pressure of 15,168

kPag (2200 psi) at 65°C (149°F). Since

that time the reservoir has been

depleted to a current reservoir

pressure of 11,032 kPag (1600 psig).

In order to perform laboratory tests on

the field it was desired to recombine

separator oil and gas samples to

represent the present in situ liquid

phase.

PVT TESTS • designed to study and quantify the phase behavior

and properties of a reservoir fluid at simulated

recovery conditions.

• The PVT tests are conducted in the absence of

water.

• The majority of tests are depletion experiments,

where the pressure of the single phase test fluid is

lowered in successive steps either by increasing the

fluid volume or removing part of it.

• The reduction of pressure results in formation of a

second phase, except in dry and wet gas mixtures.

• An important test on all reservoir fluid samples is the

determination of the fluid composition.

• The most common method of compositional analysis of high

pressure fluids is to flash a relatively large volume of the fluid

sample at the atmospheric pressure to form generally two

stabilized phases of gas and liquid.

• The two phases are individually analyzed and then

numerically recombined, using the ratio of the separated

phases. The gas and liquid phases are commonly analyzed

by gas chromatography and distillation, respectively.

• The above analysis approach, known as the "blow-down"

method, can give reliable results for large samples of high

pressure liquids, where the error involved in measurement of

the two phase ratio is relatively small. For small samples or

high pressure gases, where the condensate volume formed

by blow down is low, the technique is unreliable.

CRUDE OIL ANALYSIS

1- ELEMENTAL (ULTIMATE) ANALYSIS

2- Analysis For General Characteristics of

Crude Oil

3- Compositional Analysis:

4. Refinery Distillates Tests

http://en.wikipedia.org/wiki/File:RefineryFlow.png

+

_

Gases

L.Naphtha

H.Naphtha

Kerosene

Gas Oil

Diesel Oil

Fuel Oil (residue)

Crude

Oil

Pump

Oil Tank

Filter H.Ex.

Desalter

Pre

Flash

Tower

Atmospheric Distillation

Tow component mixture is contained in a

vessel.

When heat is add, the more volatile material

( red dotes ) start to vaporize.

The vapor contains

A higher proportion

of red dots than

dose the original

Liquid.

Oil treating requires a knowledge of

emulsions.

water-in-oil emulsion

Oil-in-water emulsion

Water-in-Oil

Emulsion Oil-in-Water

Emulsion

Separated

Oil & Water

The objective: Is to separate the oil from the water, or to break the emulsion. Generally, the emulsion must be: Heated ,and Emulsion breaking chemical added

To accomplish this.

VACUUM DISTILLATION

GAS

OIL

LIGHT W. D.

MEDIL W. D.

HEAVY W. D.

RESIDUAL W. D.

Pump Pump

hydrodesulfurization.

hydrodesulfurization.

Platforming process.

Iso. C4

5. LUBRICATING

OILS TESTS

Lubrication Principles

• 1. Friction

• Friction is a force that resists relative motion

between two surfaces in contact.

• Friction may be desirable (Tire on pavement FOR

braking)or undesirable (operation of engines).

• The energy expended in overcoming friction is

dispersed as heat and is considered to be wasted.

• This waste heat is a major cause of excessive wear

and premature failure of equipment.

• Two general cases of friction occur: sliding friction

and rolling friction.

• A. Sliding friction.

• To visualize sliding friction, imagine a steel block lying on a

steel table. Initially a force F (action) is applied horizontally in

an attempt to move the block. If the applied force F is not

high enough, the block will not move because the friction

between the block and table resists movement. If F is

increased to be sufficient to overcome the frictional

resistance force f and the block will begin to move. At this

precise instant, the applied force F is equal to the

resisting friction force f and is referred to as the force of

friction.

• B. Rolling friction.

• When a body rolls on a surface, the force resisting the motion

is termed rolling friction or rolling resistance.

Experience shows that much less force is required

to roll an object than to slide or drag it.

• 2. Wear

• Wear is defined as the progressive damage

resulting in material loss due to relative contact

between adjacent working parts.

• Although some wear is to be expected during

normal operation of equipment, excessive friction

causes premature wear, and this creates significant

economic costs due to equipment failure, cost for

replacement parts, and downtime. Friction and wear

also generate heat, which represents wasted energy

that is not recoverable.

• In other words, wear is also responsible for overall

loss in system efficiency.

Lubrication and Lubricants

a. Purpose of lubrication.

• The primary purpose of lubrication is to reduce wear

and heat between contacting surfaces in relative

motion.

• While wear and heat cannot be completely

eliminated, they can be reduced to negligible or

acceptable levels.

• Lubrication is also used to reduce oxidation and

prevent rust; to provide insulation in transformer

applications; to transmit mechanical power in

hydraulic fluid power applications; and to seal

against dust, dirt, and water.

BASE OIL PRODUCTION

Solvent Extraction Process

SOLVENT DEWAXING PROCESS

L.P. PROPANE

R.W.D.

P.+W.D

P.+BITUMEN

P.

W.D.

P.

BITUME

Greases

•Greases = OIL + Thickening AGENT

•Thickening AGENT = Soap of

Na, Al, Ba, Ca, Li, Sr

Or Mixed Soaps

•Soap = Fatty acid + M

•M = Na , Al, Ba, Ca, Li, Sr

Types of Oil

• PARAFINIC OIL

• NAPHTHENIC OIL REFINED

• MANUFACTURED SYNTHETIC

• a. Paraffinic oils.

• Paraffinic oils contain paraffin wax and are the most

widely used base stock for lubricating oils. In

comparison with naphthenic oils, paraffinic oils

have:

• ! Excellent stability (higher resistance to oxidation).

• ! Higher pour point.

• ! Higher viscosity index.

• ! Low volatility and, consequently, high flash points.

• ! Low specific gravities.

• b. Naphthenic oils.

• These oils do not contain wax and behave

differently than paraffinic oils. Naphthenic oils have:

• ! Good stability.

• ! Lower pour point due to absence of wax.

• ! Lower viscosity indexes.

• ! Higher volatility (lower flash point).

• ! Higher specific gravities.

• Naphthenic oils are generally reserved for

applications with narrow temperature ranges and

where a low pour point is required.

• c. Synthetic oils.

• Synthetic lubricants are produced from chemical

synthesis rather than from the refinement of existing

petroleum or vegetable oils.

• These oils are generally superior to petroleum

(mineral) lubricants in most circumstances.

• Synthetic oils perform better than mineral oils in the

following respects:

• ! Better oxidation stability or resistance.

• ! Better viscosity index.

• ! Much lower pour point, as low as -46 oC (-50 oF).

• ! Lower coefficient of friction.

DIS ADVANTAGES: HIGH PRICE

• Synthetic lubricant categories.

Several major categories of synthetic lubricants are available including:

• (a) Synthesized hydrocarbons. Polyalphaolefins and dialkylated

benzenes are the most common types. These lubricants provide

performance characteristics closest to mineral oils and are compatible

with them.

• Applications include engine and turbine oils, hydraulic fluids, gear and

bearing oils, and compressor oils.

• (b) Organic esters. Diabasic acid and polyol esters are the most

common types. The properties of these oils are easily enhanced through

additives. Applications include crankcase oils and compressor lubricants.

• (c) Phosphate esters. These oils are suited for fire-resistance

applications.

• (d) Polyglycols. Applications include gears, bearings, and compressors

for hydrocarbon gases.

• (e) Silicones. These oils are chemically inert, nontoxic, fire-resistant,

and water repellant. They also have low pour points and volatility, good

low-temperature fluidity, and good oxidation and thermal stability at high

temperatures.

Lubricant Additives

The SAE classification of oils

• S A E

• Society of Automotive Engineers

• The SAE classifies motor oils according to

certain viscosities and very general

temperature ranges at which they can be

used.

• Automobile and equipment manufacturers

also specify which oil should be used for a

particular ambient temperature operation.

• Today, most automobiles and trucks

use multi-viscosity oils.

• Multi-viscosity petroleum oils are

manufactured by starting with a

lower viscosity base stock oil and

blending in Viscosity Index

Improvers (VI’s).

• The purpose of the VI’s are to allow

a lower viscosity oil, such as a SAE

10W oil to flow like a 10W oil at low

ambient temperatures (such as

during cold starting) and also flow

like a SAE 30W oil at higher ambient

and operating temperatures.

• The resultant formulation is called a

multi-viscosity oil, and in this

example, would be called a

SAE 10W-30.

6. NATURAL GAS

Natural gas is commercially produced from

oil fields and natural gas fields

from oil wells is called from reservoirs that contain

(casing head gas or only gaseous constituents

associated gas), when and no (or little) petroleum

it is in solution with called (unassociated gas).

Petroleum in the

reservoir called

(dissolved gas),

Natural gas is also found in coal beds (as coalbed methane). It

sometimes contains significant quantities of ethane, propane,

butane, and pentane—heavier hydrocarbons removed prior to use

as a consumer fuel—as well as carbon dioxide, nitrogen, helium

and hydrogen sulfide.

Types of natural gas vary according to composition.

There is dry gas or lean gas, which is mostly methane, and

wet gas, which contains considerable amounts of higher-

molecular-weight and higher-boiling hydrocarbons. Sour gas

contains high proportions of hydrogen sulfide, whereas sweet

gas contains little or no hydrogen sulfide. Residue gas is the

gas remaining (mostly methane) after the higher-molecular-

weight paraffins have been extracted). Casinghead gas is the

gas derived from an oil well by extraction at the surface.

Natural gas has no distinct odor and its

main use is for fuel, but it can also be used

to make chemicals and liquefied petroleum

gas.

Composition of Associated Natural Gas from a Petroleum Well

0.08

Natural gas processing:

Uses of Natural Gas: • Power generation : Natural gas is a major source of electricity generation through

the use of gas turbines and steam turbines. Most grid peaking power plants and

some off-grid engine-generators use natural gas.

• Domestic use : Natural gas is supplied to homes, where it is used for such purposes

as cooking in natural gas-powered ranges and/or ovens, natural gas-heated clothes

dryers, heating/cooling and central heating.

• Transportation: Compressed natural gas (methane) is a cleaner alternative to other

automobile fuels such as gasoline (petrol) and diesel.

• Fertilizer: Natural gas is a major feedstock for the production of ammonia, via the

Haber process, for use in fertilizer production.

• Aviation: Recently a development programs are running to produce LNG- and

hydrogen-powered aircraft. It claims that at current market prices, an LNG-powered

aircraft would reduce cost to 60%, with considerable reductions to carbon monoxide,

hydrocarbon and nitrogen oxide emissions. The advantages of liquid methane as a jet

engine fuel are that it has more specific energy than the standard kerosene mixes do

and that its low temperature can help cool the air which the engine compresses for

greater volumetric efficiency, in effect replacing an intercooler. Alternatively, it can be

used to lower the temperature of the exhaust.

• Hydrogen: Natural gas can be used to produce hydrogen, with one common method

being the hydrogen reformer.

• Other: Natural gas is also used in the manufacture of fabrics, glass, steel, plastics,

paint, and other products.

PROPERTIES AND TEST METHODS

• SAMPLING: (ASTM D-1145, ASTM

D-1247, ASTM D-1265).

• Usually achieved

using stainless steel

cylinders, piston

cylinders (ASTM D-

3700), glass cylinder

containers or polyvinyl

fluoride (PVF)

sampling bags may

also be used

Calorific Value (Heat of Combustion)

• Various types of test methods are available for the direct determination of

calorific value (ASTM D-900, ASTM D-1826, ASTM D-3588, ASTM D-

4981). The most important of these are the Wobbe index,

[WI; or Wobbe number = calorific value / (specific gravity)

• and the flame speed, This factor can be calculated from the gas analysis.

• Another important combustion criterion is the gas modulus,

M = P/W,

• where P is the gas pressure and W is the Wobbe number of the gas.

• This must remain constant if a given degree of aeration is to be

maintained in a preaerated burner using air at atmospheric pressure.

Composition

• because of the lower-molecular-weight constituents of

these gases and their volatility, gas chromatography

has been the technique of choice for fixed gas and

hydrocarbon speciation and mass spectrometry is also

a method of choice for compositional analysis of low-

molecular-weight hydrocarbons (ASTM D-2421, ASTM

D-2650). ASTM D-1945 is a test method covers the

determination of the chemical composition of natural

gases and similar gaseous mixtures.

• Once the composition of a mixture has been

determined it is possible to calculate various

properties such as specific gravity, vapor pressure,

calorific value and dew point.

7. SUDAN

CRUDE OIL

Oil in Sudan

• Oil exploration in Sudan was first initiated

in 1959 by Italy’s Agip oil company in

the Red Sea area.

• Several oil companies followed Agip in the

Red Sea Area but none were successful

in their exploration efforts.

• The first oil discovery in Sudan was made

by Chevron in the south of Sudan in

1979, west of the Muglad.

Chevron continued its successful exploration

and made more significant discoveries in the so

called Unity and Heglig fields.

- In 1983 Chevron, Royal Dutch Shell, the

Sudanese government, and the Arab Petroleum

Investments Corporation (Apicorp) formed the

White Nile Petroleum Company in order to build

an oil pipeline from the Sudanese oil fields to Port

Sudan on the Red Sea.

- In 1999 the pipeline became operational and

carried the first Sudanese oil exports to Port

Sudan.

Oil reserves and production:

• Reserves: according to BP statistical

review of world energy 2006, Sudan has a

proved oil reserve of 6.4 thousand million

barrels. The oil exploration has been

limited to the central and south central

regions. It is estimated that the country

holds vast potential reserves in the east,

north-west and south of the country.

• Production:

• In 1999 the construction of an export pipeline,

that connected the Heglig oil fields in central

Sudan to Port Sudan on the Red Sea, was

completed. This led to a considerable increase

in oil production, and the first oil export in the

history of Sudan. Since then production has

increased steadily.

• In April 2006 another 1400 km pipeline, from

Upper Nile in Sudan’s south-east to the eastern

Port Sudan became operational. This pipeline

will raise production to 500,000 b/d in 2006 and

it is estimated that it will double the production in

2007.

Sudan Oil Blocks:

Blocks 1, 2, and 4 (Nile Blend):

Heglig and Unity fields

maximum capacity is 450,000

bbl/d.

Blocks 3 and 7 (Dar Blend):

Adar Yale and Palogue oil fields

maximum capacity is 500,000

bbl/d.

Block 5a:

Thar Jath and Mala fields

maximum capacity is 60,000

bbl/d.

Block 6:

Fula field

maximum capacity is 40,000

bbl/d

• Other Blocks:

• Block B: Block B is located in southeastern Sudan and is licensed to Total.

The company has faced several problems resulting from conflict in the

area, licensing problems, and, more significantly, the existing consortium

continues to seek a third partner to replace Marathon Oil, a U.S. company

that was forced to pull out of its 32.5 percent interest as a result of U.S.

sanctions.

• Block 5B: Block 5B is located in the southern Muglad Basin and was

initially under exploration by ONGC Videsh (23.5 percent stake) and

Lundin (Sweden 24.5 percent) in partnership with Sudapet (13 percent),

and Petronas (39 percent). In early 2009, two major stakeholders, ONGC

and Lundin pulled out after negative drilling results. In August 2009, the

National Petruleum Commision approved the participation of Ascom, a

Moldovan firm in block 5B.

• Block EA: According to the BBC, the NPC recently mapped out a new oil

concession called EA. This block is a long narrow strip that runs along

existing fields in the Muglad Basin.

Congratulations!

You have won a

million dollars!

THANK YOU

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