Introduction to oil and gas exploration and processing

Introduction to Oil & Gas
Exploration and Processing
info@ifluids.com www.ifluids.com

iFluids Engineering
On-Line Webinar Session 2020
“Introduction to Oil & Gas Exploration
and Processing”
PRESENTER
N. NAGARAJAN, M.E.(Chemical)
Technical Director, iFluids Engineering
Chairman, IIChE – CRC.
iFluids Engineering Webinar Presentation, 19th July 2020

OIL & GAS INDUSTRY – AN OVERVIEW
The dependency on Oil & Gas products, are evident in
all aspects of our daily life -
•How they were formed ?
•How are oil and gas deposits located?
•How are they safely and efficiently extracted for
onward processing without creating detrimental
environmental impacts ?
This is a comprehensive presentation designed to give
an overview and to introduce oil & gas operations.
Introduction to Oil & Gas sector 19th July 2020

Fossil Fuels
What is a fossil fuel?
➢ Fossil fuels are hydrocarbons such as Coal, Oil and Natural gas.
➢ Sourced from the organic remains of prehistoric organisms.
How do fossil fuels form?
❖ Oil and Gas are formed from the organic remains of marine organisms.
❖ Coal is typically formed in non-marine settings from the remains of land
vegetation.
Oil & Gas formation
▪ Oil and Gas formation begins with the accumulation of organics on the sea-
floor.
▪ The sediment pile becomes deeper and the organics within it are
subjected to Heat and Pressure which leads to formation of Oil and then
Gas.
▪ The geometry of the reservoir and cap-rock bodies must be such that the
hydrocarbons become trapped; usually folding will suffice.

Exploration methods
Visible surface features
❖ Oil Seeps.
❖ Natural Gas Seeps.
❖ Pock marks (Under water craters made by escaping gas).
Exploration Geo-Physics
➢ Gravity Survey (Gravity meter).
➢ Magnetic Survey (Magnetometer).
➢ Passive Seismic or Seismic Reflection Surveys.
➢ A significant amount of Geological, Structural and Seismic
investigation must first be completed to redefine the
potential Hydrocarbon drill location from a Lead to a
Prospect.

Oil & Gas Exploration Economics
•Oil exploration is an expensive, High-risk operation.
•Exploration is generally only undertaken by very large
Corporations or National Governments.
Cost of Oil Exploration :
➢ Shallow shelf oil wells cost USD$10 – 30 Million.
(e.g. North sea)
➢ Deep water wells can cost up to USD$100 million plus.

Definition of Oil Reserves
Oil reserves are primarily a measure of geological Risk of the Probability of oil
existing and being producible -
(A) Under current economic conditions.
(B) Using current technology at current prices.
(C) With current commercial terms and Government consent.
Three categories of reserves are : Proven, Probable, and Possible Reserves
-
◼ Proven reserves - Defined as oil and gas "Reasonably Certain" to be producible
satisfying (A),(B) & (C) - also known in the industry as 1P. e.g.,P90 - i.e. having
a 90% certainty of being produced.
◼ Probable reserves - Defined as oil and gas "Reasonably Probable" of being
produced satisfying (A),(B) & (C) - Industry specialists refer to this as P50 - i.e.
having a 50% certainty of being produced. This is also known in the industry
as 2P or Proven plus probable.
◼ Possible reserves - i.e. “Having a chance of being developed under favourable
circumstances" - Some industry specialists refer to this as P10 - i.e. having a
10% certainty of being produced. This is also known in the industry as 3P or
Proven plus probable plus possible.

PDC bit for well drilling
Tricone rock bit
Well drilling is the process of drilling a hole in the ground for the extraction of Natural
Resources such as
❖ Water , Natural gas or Crude Oil.
Drilling for the exploration of the natural Resources underground (such as Oil & Gas) is
best described as borehole drilling, or “Drilling”.
Well drilling can be done either manually or mechanically and the nature of required
equipment varies from Simple and cheap to very Sophisticated.
Drill bits are made of Diamond (due to it’s hardness).
Drilling Equipment

Step 1: Gathering Seismic information
The existence of oil and natural gas may be determined by using sound waves
(Process called 3-D seismic). Vibrations are sent underground and reflected back to
a listening device on the surface. Different zones and formations below the earth
reflect these vibrations at different speeds, allowing operators to generate a
picture or cross section of the potential zones and structures located beneath the
surface.
Step 2: Signing the Leasing Agreement
Standard Oil and Natural gas lease forms establish partnership between the
mineral Owner and Operator for the drilling and production of oil and natural gas.
The mineral owner bears no risk, but in return receives regular royalty payments
based on the well’s production revenue. The operator incurs all risks and costs
associated with drilling and producing the well.
Step 3: Preparing the Drill site
After a lease agreement is signed, Operator builds drill sites, utilizing as small an
area as possible that will safely accommodate the drilling Rig and associated
equipment. Once drilling is completed, the drill site is typically downsized to a
minimum area for the surface production equipment.
Drilling and Production Process

Step 4: Drilling
Once the drilling rig and other necessary equipment are in place, the drilling
process begins. The depths of wells vary greatly depending on the formation and
play. Some operators specializing in horizontal drilling techniques, begin with
vertical hole before drilling horizontally into the potential productive zone to
recover the maximum reserves.
Step 5: Completing
As a well reaches the completion phase, the original drilling rig is removed and a
smaller completion rig is moved-in to perforate and treat the potentially
productive zones. These high-technology “fracing” completion processes stimulate
production by pressuring completion fluids and materials into the zone and creating
cracks for the gas to flow up into the wellbore.
Step 6: Producing
A wellhead or “Christmas tree” is placed on top of the existing well site to control
and regulate the flow of gas into a pipeline in order for the gas to be transported
to market through a regional pipeline system.
Drilling and Production Process (Contd.)

In Petroleum and Natural gas extraction, a Christmas tree, or "tree", (not “Wellhead"
as sometimes incorrectly referred to) is an assembly of Valves, Spools, and Fittings
used for an Oil well, Gas well, Water injection well, Water disposal well, Gas
injection well, Condensate well and other types of wells. It was named for its
resemblance to a “Decorated Tree”
Drillin
g
Wellhead Equipment - Christmas Tree

TYPES OF WELLS

History of Off-Shore Oil & Gas Exploration
When did the Offshore Industry begin?
 First Submerged Oil Well around 1891 at Grand Lake, St. Marys in Ohio, USA.
 Submerged Oil well in Salt water 1896 at Santa Barbara channel in California, USA.
 The First platform out of sight of land was built at Louisiana Offshore in 1947, USA.
 Initial Platforms developed in Shallow waters at depths of 14 to 20 ft.
 The offshore industry has moved from the First Platform to the present stage of
safely producing at 7000 feet (2100 meters) of water and safely drilling at 10000
feet (3050 meters) of water.
 The industry is still learning & there is more to come !!

Louisiana : Sep.9,1947 Ship Shoal Block 32

Lake Maracaibo, Venezuela in 1920

Caspian Sea - Soviet Era Up To 100 KM Offshore
➢ The Oil Rocks, a
full town created
in 1947 on the
Azerbaijani side
of the Caspian
Sea
➢ The pearl of
Soviet and
Azerbaijani
ambition in the
1950s.

Types of Off- Shore Facilities
 Fixed Platforms – up to 520 m water depth
 Compliant Towers – 450 to 900 m water depth
 Semi-Submersible Platforms – 60 to 3050 m water depth
 Jack-up Platforms – 120 to 170 m water depth
 Drill Ships – Can drill in water depths up to 3660 m
 Tension-leg Platforms – 200 to 1300 m water depth
 Spar Platforms – 588 to 2438 m water depth
 Floating Production systems - FPSO, FSO

Fixed Platform - Installation

Jacket Load-out (Transportation)

Completed Production Platform
A typical offshore
Oil / Gas platform.

Concrete Piled Platform

Typical Fixed Platforms in operation

Semi – Submersible Platform

Semi – Submersibles in Operation

Platform P-51 off the Brazilian coast is a
semi-submersible platform

Jack-up Platform – Different types

Transportation of Jack-up Unit

Operating Jack-up Unit

Drill Ships – Earlier and Modern versions
Zapata Sidewinder Offshore Malaysia,1963

Floating Production Systems

Foinaven FPSO

Summary of Deep Water Production Systems

World’s first Advanced Floating Gas Refinery

Crude oil / Natural gas Characteristics
➢ A mixture of hundreds of hydrocarbon compounds
(including Oil and Gas).
➢ Components range from Methane to Asphalts.
➢ Also contains emulsified salt water (Formation water).
➢ Hydrocarbons are Lighter than water.
➢ Crude types range from very Light such as Condensate to
very Heavy as Asphalt.
➢ Can be Sweet (no sulfur) or Sour (with Sulfur).
➢ Characterized by Density, expressed in degrees API
gravity.

API Gravity
API gravity is a measure of Oil Density
Given by the formula -
❑ Degrees API = (141.5/SG at 60 °F) - 131.5
❑ Water has an API gravity of 10 degrees
➢ Light Crude Oil > 31, API Gravity
➢ Intermediate = 22-31, API Gravity
➢ Heavy crude < 22, API Gravity

Hydrocarbon Chemistry – Paraffins
CH4 : Methane , BP (-161 deg C)
C2H6 : Ethane , BP (- 88 deg C)
C3H8 : Propane , BP (- 40 deg C)
C4H10 : Butane (normal and iso-) ,
BP (0 deg C/ -12 deg C)
Hydrocarbon Families - Paraffins

Hydrocarbon Families - PONA
Types of Hydrocarbon Compounds
➢ Paraffins : straight or branch chain : CnH2n+2 > Saturated
➢ Cycloparaffins (Naphthenes) : CnH2n > Saturated
➢ Alkenes (Olefins) : Mono-olefins : CnH2n > Unsaturated
➢ Aromatics : Stable Benzene : CnH2n-6 > Unsaturated
➢ Diolefins, Dienes or Alkenes : CnH2n- 2 > Unsaturated
➢ Alkynes : CnHn > Unsaturated
ACETYLENE
1,3-BUTADIENE

FUNDAMENTALS OF OIL AND GAS
Oil bearing layer
Impervious layer above
oil bearing rock layer
Water layer below oil
Gaseous layer at
top of oil field
Ground or sea bed level
Diagram of Oil and Gas bearing deposits or fields

Overall Block Diagram - Oil and Gas Industry

CRUDE OIL CONSTITUENTS
CRUDE OIL : From the Well
❖ Mixed Hydrocarbon Oils
❖ Gases
❖ Water
❖ Dirt (Minerals) / Contaminants (Metals)
Field separation
➢ May be several stages of pressure letdown and stilling
➢ Separates Hydrocarbon Mixture into
❑ Gas (Re-injected, Flared or sent to Processing)
❑ Oil (Crude Oil - for Shipment and/or Storage)
❑ Water (for Treatment & then Disposal)
❑ Solids ( Sand, Dirt - for Disposal)

GAS TO EXPORT
OR REINJECTION
OIL TO EXPORT
WATER TO DISCHARGE
OR REINJECTION
REJECT OIL
DEOXYGENATION
FILTRATION
CHEMICAL
INJECTION
CHEMICAL
INJECTION
DISINFECTION
COMPRESSIONDEW POINT
CONTROL
GAS DEHYDRATION
AND DEWPOINTINGGAS
SWEETENING
❖ WELL HEAD SEPARATION
❖ PRIMARY SEPARATION
❖ PARTIAL PROCESSING
PRODUCED
WATER
TREATMENT
ELECTROSTATIC COALESCENCE
Typical processing requirements for well fluids
prior to export
Introduction to Oil & Gas sector
19th July 2020

Typical Field Separation Scheme
From the
Well FIRST STAGE
SECOND
STAGE
THIRD
STAGE
Water and
solids
Water and
solids
Water and solids
Associated Gas to
Shipment or Re-injection
Crude Oil to
Desalting or
Shipment or StorageHEATING
(Optional)
To HP
Flare
To MP
Flare
To LP Flare

Typical Gas Processing Steps
Gas Processing
❖ At the well : Remove dirt, free water, condensate etc. and make
it ready to transport.
❖ Gas to be stable and at a high enough pressure to reach its
destination. Minimal processing is normally done close to the
well.
Typical operations (Simple clean-up)
➢ Glycol or Methanol injection - to absorb water vapour and
prevent hydrate formation.
➢ Corrosion Inhibitor injection - to prevent gas contaminants from
damaging the pipeline.
➢ Heating - so that frictional pressure drop and associated
temperature decrease does not result in condensate fallout.
➢ Compression - to ensure the gas will reach its destination.

Typical Glycol (TEG) Drying System
Lean Glycol
Cooler
Lean-Rich
Exchanger
Rich Glycol Lean Glycol
Wet
Gas In
Dry Gas Out
Glycol
Contactor
Glycol
Pumps
Surge Drum
TEG Reboiler
Glyco
l Still
Water
vapor out
Flash Tank
Glycol
Filters Stripping column
Burner
Flash
Gas
Introduction to Oil & Gas sector
19th July 2020

Produced Water Treatment
❖ De-oiling
❖ Filtration
Typical Processes
1. Dissolved Air Flotation
(DAF)
2. Induced Gas Flotation
(IGF)
3. Hydro cyclone

Typical Oil & Gas Field Equipment
Typical Vessel type Slug Catcher
Pipeline Fluids in
Gas Out
Condensate
out
Glycol/Methanol/Water/Dirt
out
Vortex Breaker on
raised pipe
Demister
Pad
Liquid level
Baffle plate

A Typical Finger type Slug Catcher
80 -100 meters long or more, and sloped
towards liquid outlet end
Gas Out
Pipeline Fluids in
Liquids Out

Water/Dirt
Out
Oil Out
Gas Out
Inlet pipe with
baffle device
Perforated Inlet
Calming Baffle
plate
Overflow
Weir Plate
Coalescer
Plate Pack
(optional)
Demister Pad
or Vane pack
(optional)
Vortex
Breakers
Typical Three Phase Separator

Typical Oil Processing Facility Schematic
Manifold
Crude from
Wellhead
Water
Conditioner
Dehydration/d
esalting
To Fuel
Gas
To Flare
Crude Oil to Shipping
Water to Re-injection
or Disposal
Heat
Exchanger
Heating
Fluid

Final Oil Processing prior to Shipment
Dehydration / Desalting
❖ Primary water removal
❖ Electrostatic DEHYDRATION / DESALTING
Stabilisation
❖ Mild heating to boil off the last of the light fractions
(mostly i and n-butanes)
❖ Pressure reduction to allow last of light ends to evaporate
❖ Stabilisation Column

Electrostatic Crude Desalter / Dehydrator
1. Vessel is liquid full.
2. Salt is dissolved in water phase.
3. Water is emulsified in small droplets.
4. Alternating electrical field acts on
conductive salt water droplets.
5. Droplets vibrate as a result, collide,
coalesce and fall out of emulsion.

Crude Stabilization
Crude Oil
Stabilized Oil
Light Gas
Re-boiler
Feed /
Effluent
Exchanger
Water Draw-off

Pipeline – Launcher / Receiver

Gauge PlateCylindrical Brush Pig
Brush
Foam Pig
Gauging Pig
Sphere Pig - Used for
separation or displacement
Typical Pigs

Introduction to Oil & Gas Exploration / Processing
➢ Questions ?
❖ Thank You !

Introduction to oil and gas exploration and processing

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