appendix 169
168 appendix
Appendix
Upstream
Downstream
Operations Data
Top of reservoir
dammam dome
A 3-D reservoir model of the Dammam
Dome from 2008 is aligned with the
corresponding area from the first map
of the Dammam Dome, drawn in 1934.
Geological fault
Reservoir porosity
reflected in different
colors
reservoir quality
The 3-D model illustrates the reservoir,
roughly 1,500 meters below ground.
Poor
Good
Excellent
appendix 171
170 appendix
Upstream
The origins of hydrocarbons
Upstream encompasses all the activities from the drill bit to the refinery: the
Land
Sea
exploration for, and development, production and processing of, oil and gas.
Water injection, oil stabilization, gas processing and pipelines are included
within the scope of upstream operations.
Upstream begins with earth scientists searching for oil and gas by examin-
Tiny forms of sea life such
as plankton die and accumulate
on the ocean floor.
ing rock outcrops on the surface to try to understand the subsurface strata.
They integrate their interpretations with data collected from inside the well:
from drill cuttings (bits of rock that rise to the surface as a well is drilled),
core samples and wire-line logs (instruments that record electrical values,
Layers of sediment form as the
accumulation process continues
over time.
radioactivity, temperature and other rock properties). The integrated data
are used to identify prospects—areas likely to contain petroleum.
Once a prospect has been identified, geoscientists acquire and interpret
seismic data to develop integrated geological and geophysical models that
are used to select the best drilling locations. After a discovery is made, drilling
to delineate and develop a field takes place, and reservoir engineers design
production plans. Improvements in technology continue to increase recovery
rates, enabling geoscientists and petroleum engineers to manage reservoirs
efficiently and for the long term. Saudi Aramco also places significant emphasis
on operations safety and environmental protection.
The Origins of Oil and Gas
Oil and gas originate almost entirely from the remains of ancient
plants and animals as shown in the diagram on the facing page. The solar energy absorbed by
Parts of the dead material change
to hydrocarbons mixed with other
sedimentary materials.
Layers become more and more
compresssed as further layers
settle on top.
these organisms and stored as carbon molecules in their bodies has been recycled into petroleum
energy in the form of organic compounds composed mostly of hydrogen and carbon. These
hydrocarbon compounds were created when microscopic marine organisms and plant matter
were buried by layers of sediment and, over millions of years, transformed through bacteria, heat
and pressure into oil and gas, which gradually seeped up through layers of rock, collecting in
underground structures called traps.
The fossilized remains of ancient marine
organisms, seen in the core samples
pulled up from wells thousands of
meters deep and collected from rock
outcrops on the surface, yield a wealth
of clues to geologists searching for
oil and gas. These specimens, as seen
by a scanning electron microscope in
EXPEC, are acritarchs, fossil marine
organisms of unknown biological
affinity, and date to the early Silurian
age, about 430 million years ago.
New material–depositing sediment
forms an impervious layer called
cap rock.
Gas
Oil
Gas, oil and water
Earth movements cause folds
in the crust.
appendix 173
172 appendix
Stratigraphy of Eastern Saudi Arabia
The rich oil and gas fields of Saudi Arabia, located
mainly in the Eastern Province, are linked to the region’s long history of relative tectonic stability
in its subsurface. The virtually flat platform of the Arabian Shelf, which underlies the middle and
siberia
eastern side of the Arabian Peninsula and its shallow eastern offshore area, enabled an almost
uninterrupted accumulation of sediments, which provided both the source for oil and gas and
the reservoirs in which these hydrocarbons accumulated.
europe
china
turkey
iran
generalized cross section
of saudi arabia
tibet
north
america
indochina
southeast
asia
in millions of years
africa
sea level
arabia
south
america
–304.8m
india
The final 10 million years of the late
Jurassic Period witnessed significant
environmental changes, as shallow
seas receded and advanced, leaving
behind alternate layers of nonporous
anhydrite and porous and permeable
limestone. The latter layers formed the
Arab Zone, which contains the world’s
largest petroleum reserves. Over the
course of millions of years, infrequent
tectonic events led to the formation of
structural traps, capped by anhydrite,
which captured the hydrocarbons.
e a r ly j u r a s s i c 1 9 5 m i l l i o n y e a r s a g o
key
The enormous hydrocarbon reservoirs
in what became Saudi Arabia
accumulated in carbonate sedimentary
rocks deposited in the late Jurassic
Period, around 150 million years ago.
ancient Landmass
–609.6m
cretaceous period
67–140 million years ago
australia
a n ta r c t i c a
limestone
–914.4m
120
The Earth’s interior, composed of semi-molten
rock, is in constant motion. The outer rigid layer, the lithosphere, consists of large plates
Zubair
Zone
130
Upper
Ratawi Zone
135
Lower
Ratawi Zone
140
Manifa
Zone
collide with each other in a process called plate tectonics, forming mountains, basins and the
continents themselves.
Arab B
Member
Arab C
Member
animals appeared in great numbers.
About 100 million years later, in the early Devonian Period, the Paleozoic oceans began to
close, and eventually the supercontinents of Gondwana and Euramerica collided to form Pangea.
jurassic period
which included the landmass of Arabia, stretched from the Equator to the South Pole, and it and
the other continents were flooded by shallow seas. Algae were dominant, and hard-shell marine
140–204 million years ago
Around 1.1 billion years ago in the Precambrian, the Earth’s landmasses formed one
of Gondwana formed around 514 million years ago, in the late Cambrian Period. Gondwana,
150
In the last 20 million years, the Red Sea opened, rifting Arabia away from Africa.
–2,133.6m
–2,438.4m
Hanifa
Zone
Hadriya
Zone
Fadhili
Zone
Jurassic Period, about 180 million years ago. This age was dominated by the giant dinosaurs,
Jurassic Period, enormous layers of organic matter accumulated in what became Saudi Arabia.
–1,524m
Arab D
Member
Mid-Jubaila
Zone
Pangea began to break apart in three main episodes, with the first occurring in the middle
the first appearance of birds and extensive inland seas where, 30 million years later, in the late
porous limestone
–1,219.2m
–1,828.8m
Arab A
Member
supercontinent, Rodinia, which, some 250 million years later, broke apart. The supercontinent
sandstone
Bahrain
Zone
that slide over the semi-molten layer. These plates pull apart from, slip past, dive under and
anhydrite
shale
Modern Landmass
seafloor spread ridge
A Brief Geological Timeline of Saudi Arabia
sand and mud
100
subduction zone (triangles point
in the direction of subduction)
key
165
–2,743.2m
appendix 175
174 appendix
Petroleum Traps
Niyashin
Rimthan
As Sayd
El Haba
Reservoir rock and water
Juraybi‘at
Abu Hadriya
Duhaynah
Jaladi
Bakr
Faridah
Manifa
Kurayn
Sharar
Habari
Watban
Cap rock
Maharah
Ribyan
Harqus
Namlan
Wari‘ah
Gas
Marjan
Lawhah
Hasbah
Dibdibah
Jauf
Suban
An anticline trap is an upward fold
in the layers of rock shaped like an
arch. Petroleum migrates into the
highest part of the fold and is prevented from escaping by an overlying
bed of impermeable cap rock. The
great majority of oil reservoirs are
found in anticline traps.
Zuluf
Safaniya
Dhib
Karan
Jana
Jurayd
Rabib
Berri
Khursaniyah
Fadhili
Samin
Hamur
Arabiyah
Abu Sa‘fah
Qatif
Oil
bahrain
Dammam
Dhahran
Fazran
Jaham
a
Abqaiq
r
a
b
ia
‘Ain Dar
n
g
ul
f
Shedgum
Khurais
Riyadh
Gas
Oil
Reservoir rock
and water
Shiblah
Hilwah
Manjurah
Farhah
Awtad
Warid
Mazalij
Sirayyan
Sahba
Dilam
Arsan
Abu
Sanaman
Shidad
Raghib
Wudayhi
Midrikah
Duayban
Haradh
Jufayn
Dirwazah
Niban
Nujayman
Halfa
Nuayyim
Muraiqib
Abu Sidr
Kassab
Qamran
Maghrib
Sham‘ah
‘Amad
Kahla
Shaybah
Shutfah
North
Ramlah
Tukhman
Waqr
Ghinah
Marzouk
Jawb
Zimlah
Shaden
Hawtah
Lughfah
Yabrin
Abu Markhah
Nisalah
united arab
e m i r at e s
Tinat
Mulayh
Burmah
Hazmiyah
Harmaliyah
Abu Rakiz
Khuzama
q ata r
Ghawar
Qirdi
Hawiyah
Abu Jifan
Cap rock
A fault is the result of horizontal layers
of rock being folded or deformed,
creating a fracture. When the rocks
on the two sides of a fracture move in
opposite directions, a fault is created.
A fault trap occurs when formations
on either side of a fault prevent
further migration of petroleum.
‘Uthmaniyah
Kidan
Umm Jurf
Usaylah
South
Layla
Cap rock
Gas
Oil
Stratigraphic traps occur when a
reservoir layer, also called a bed,
is sealed by other beds or by a
change in porosity or permeability
within the reservoir bed itself.
Reservoir rock
and water
key
Nearly all of Saudi Aramco’s oil and
gas fields are located in the Eastern
Province. Other fields are located in
the Central Province, south of Riyadh,
and in the Western Province, on the
Red Sea coast. Total recoverable crude
oil reserves are roughly 260 billion
barrels—the largest in the world.
Reserves of natural gas are roughly
279 trillion cubic feet, fourth largest
in the world.
Jalamid
Towns
C a p i ta l
oil field
Kahf
gas field
scale in kilometers
0
50
Sidr Midyan
Barqan
100
scale in kilometers
100
200
se
0
d
Oil and gas are formed in organic-rich layers of rock exposed to heat and
Tabuk
re
Petroleum Traps
oil and gas fields
of saudi arabia
a
pressure, called source rock. The oil and gas will migrate upward through the rock layers where,
Umluj
Al Wajh
if conditions are favorable, they will accumulate in reservoirs, layers of porous and permeable
rock such as limestone or sandstone. The migration of hydrocarbons to the surface is stopped
by an impermeable layer of rock that acts as a seal, or cap. Oil and gas accumulate only where
the reservoir and cap rock form traps.
Geologists classify petroleum traps into two basic types: structural traps, formed by Earth
movements and rock folds, and stratigraphic traps, the result of the deposition of layers favorable to the formation and trapping of petroleum. Two common examples of structural traps are
anticline and fault traps.
e s t i m at e d w o r l d w i d e c r u d e o i l r e s e r v e s
e s t i m at e d w o r l d w i d e g a s r e s e r v e s
(billion barrels) as of january 1, 2010
(trillion cubic feet) as of january 1, 2010
260
saudi arabia
211
VENEZUELA
175
137
115
CANADA
IRAN
IRAQ
1,680
Russia
1,045
Iran
895
qatar
279
saudi arabia
265
TURKMENISTAN
appendix 177
176 appendix
Exploration
The professionals in Saudi Aramco’s Exploration organization cover Saudi Arabia
on a scale that extends from wide swaths of desert, basins and mountains to the micron level.
They also consider a fourth dimension in their quest: time, which they measure in the hundreds
of millions of years.
A new road, cut through a hill, allows
a young geologist to map rock layers
near al-‘Ula, Saudi Arabia.
The Fossil Record
Core samples, drill cuttings, plugs (a kind of mini-core pulled from the
Sedimentologists and carbonate
geologists in Saudi Aramco’s Core
Lab study the separate layers, or
beds, within hydrocarbon reservoirs as revealed by core samples.
Thin sections are cut from the core
samples and examined by company
micropaleontologists, who look for
fossils of marine and land organisms, and by palynologists, who
look for ancient pollens and spores.
This short interval of a core sample,
pulled from 1,468 meters deep in the
Shaybah field, shows the contact
between crude oil and gas. The light
brown section of the core is filled
with Arabian Super Light crude oil
while the gray section is from the
gas column of the reservoir, above
the oil column. The limestone core
is composed of fragments of an
ancient bivalve, and the oil and gas
are stored in the inter-particle pore
spaces between the shell fragments.
larger core) and thin sections mounted on slides are examined by geoscientists. The rock yields a
wealth of knowledge about the reservoir: porosity and permeability, basic and structural geology,
petroleum physics, stratigraphy, sedimentology and other data.
Geoscientists are especially interested in microfossils such as pollens, spores, protists
(one-celled organisms, including algae, dinoflagellates and others) and Foraminifera—organisms
with calcium carbonate shells. The fossil record illustrates the historical environment of Arabia:
from shallow, warm seas during the Jurassic Period to glaciers and ice sheets when Arabia, in its
continental wandering, was located near the South Pole.
Fossil remains of the single-celled
aquatic organisms known as
Foraminifera serve as excellent
records of the environment and
geologic age of the rock layers in
which they are found. Foraminifera,
with their hard exoskeletons, small
size, short reproductive cycles,
prolific numbers and wide distribution over marine environments, are
especially valuable fossil clues.
A hydrocarbon reservoir is similar
to a sponge soaked with oil and
gas. Two key factors in a reservoir’s
potential productivity are how big
the holes in the sponge are and how
they connect, known as porosity
and permeability. Using a scanning
electron microscope, company
scientists can examine the reservoir
rock at the 2- to 5-micron level, close
enough to see the individual pores
in the stone, and better understand
the porosity and permeability of the
reservoir. The rock on the left reveals
poor reservoir quality, while the
sample on the right shows excellent
porosity and good permeability.
appendix 179
178 appendix
Company earth scientists and
petroleum engineers use the
latest in 3-D reservoir simulation
technology in the Upstream
Professional Development Center in
Dhahran. Such technology provides
a better understanding of prospects
before an exploratory drilling program
begins, and in reservoir development, it helps delineate fields and
place wells to optimize production.
Seismic Imaging
Seismic surveying is used in conjunction with structure drilling in the search
for oil and gas. Sound waves, produced by mechanical vibrators mounted on the underside
Reservoir Characterization
Reservoir characterization plays a critical role throughout the
productive life of an oil or gas field. Every producing reservoir has a reservoir simulation model that
of large trucks, penetrate layers of rock thousands of meters beneath the Earth’s surface. The
is continually updated with new drilling and production data and is used to develop and evaluate
sound waves are reflected back to the surface where their altered waveforms are recorded as
alternative reservoir management strategies. Because of the huge size and large well spacing of
raw seismic data. This information is manipulated by powerful computers to produce an image
Saudi Arabia’s hydrocarbon resources, Saudi Aramco has developed its own reservoir simulator,
of the underground rock formations.
POWERS (Parallel Oil Water and Gas Reservoir Simulator), to produce 3-D geo-cellular models,
comprising billions of individual cells. These reservoir models are used in reserves estimation and
reservoir simulation models, which are also used to evaluate proposed well locations.
appendix 181
180 appendix
Reservoir Nano-agents: Resbots™
One promising avenue of research in reservoir manage-
ment is the development of nano-scale reservoir robots, called Resbots. Company researchers
are studying the feasibility of deploying Resbots, 1/1,000th the size of a human hair, with the
fluids injected into a hydrocarbon reservoir. Resbots would gather information about reservoir
properties, including pressure, temperature and fluid type, in onboard memory. The Resbots
would be retrieved through production wells and the data downloaded and analyzed, helping
delineate the extent of the reservoir, map fractures and faults in the rock, define areas of higher
permeability, identify bypassed oil, optimize well placement and help design even more precise
A multilateral well extends multiple
branches within the hydrocarbon
reservoir. Multilateral wells improve
well productivity and reduce field
development costs by requiring fewer
wells to produce a field.
geological models of the reservoir. For the Resbots concept, the Exploration and Petroleum
Engineering Center (EXPEC) Advanced Research Center won the prestigious New Horizons Idea
Award at the 2008 World Oil Awards.
Drilling and Reservoir Engineering
Drilling is conducted for both exploration and production
purposes. Structure drilling is used to determine key subsurface strata. Wildcat wells are drilled
to test whether oil or gas is present in the structures that geologists have recommended. Once a
new field has been discovered, a number of delineation wells are drilled some distance apart in
order to outline the configuration and size of the field. Finally, the field is put into production by
drilling development wells in a pattern recommended by petroleum engineers. Water injection
wells inject treated seawater to maintain reservoir pressure.
Drilling technology has come a long way since the early days of the industry. Directional
drilling was first introduced in the 1920s, driven by the need to drill from difficult onshore sites
Geologists direct well drilling from
Saudi Aramco’s Geosteering Center
in Dhahran as real-time information
is transmitted from sensors near the
drill bits. The center operates 24 hours
a day, seven days a week.
and, later, from offshore platforms. Horizontal wells became popular in the 1980s and were
developed for deeper wells in the 1990s. A horizontal well penetrates a reservoir bed across the
target zone, rather than down through it, improving recovery rates. More recent developments
include multilateral wells, with multiple junctions like the branches of a tree.
Drilling wells, whether for exploration,
delineation, production or water
injection, is at the heart of the petroleum industry.
A maximum reservoir contact (MRC) well is a multilateral horizontal well with more than
five kilometers of total contact with the reservoir rock. Such wells also employ “smart” well
features that enable a reservoir management team to intervene remotely. For example, the
team can shut off one lateral without disturbing the remaining laterals. Smart wells also include
downhole sensors, which provide real-time monitoring of the well, helping optimize production
and reservoir management.
A further refinement of the MRC is the extreme reservoir contact (ERC) well, a smart
multilateral well that does not require individual control lines from the wellhead on the surface to
each lateral. This allows an unlimited number of smart laterals, which can be remotely controlled
using real-time data.
The Geosteering Operations Center (GOC) in Dhahran is staffed by teams of geologists and
engineers who monitor drilling operations anywhere in the field. They analyze downhole data
in real time to remotely guide drilling activities and ensure that each well is optimally placed.
appendix 183
182 appendix
Oil & Gas Production and Processing
Gas Production and Processing
Natural gas is processed to produce clean fuel (methane, or
For a diagram of Saudi Aramco’s oil and gas production operations and a map of production
sales gas) and feedstock (methane, ethane, propane, butane and natural gasoline). Sales gas and
facilities, see the Operations Data section.
ethane are consumed entirely by Saudi Arabia’s utilities and industry. Excess propane, butane and
natural gasoline (collectively known as NGL) that are not used by the domestic petrochemicals
Saudi Aramco’s oil and gas production operations encompass Saudi Arabia, including
territorial waters in the Arabian Gulf and the Red Sea. Totaling more than 1.5 million square
industry are exported to world markets.
kilometers, this area is larger than the combined areas of Texas, California, Oklahoma and Utah,
or of France, Spain and Germany.
gas production
Oil Production and Processing
Most oil-producing wells are free-flowing with a typical oil
Sales Gas
NGL
flow rate of 5,000 bpd. Once the oil is extracted, it is piped to a gas-oil separation plant (GOSP)
Gas Plant
where water and the majority of dissolved gases are extracted. The remaining oil is then sent to
a stabilization facility, such as the Abqaiq Plants, for final gas separation and removal of hydrogen
Sulfur
sulfide. The extracted gas is sent to Gas Operations facilities for additional processing, while the
water is injected back into the ground. This oil is now dry (no water), sweet (no hydrogen sulfide)
Oil
Gas
GOSP
Condensate
and stabilized (no gas), and can be refined or exported.
This gas-oil separation plant
(GOSP) is one of four that
perform the initial processing
of oil from the Shaybah field.
Gas
Gas
Oil
Saudi Aramco’s Master Gas System
(MGS) is fed with two types of gases:
the gases associated with crude
oil that are removed by the gas-oil
separation plants (GOSPs), and the
non-associated gases that come from
gas wells that do not produce crude
oil. Gas processing involves removing
the hydrogen sulfide (H2S) and carbon
dioxide (CO2) to produce sweet gas,
and separating sales gas (methane)
from the heavier components. The
heavier products are liquefied and
pumped to NGL plants for fractionation and final delivery to customers.
The H2S is converted to elemental
sulfur and sold to domestic and
export markets.
Water
Water
Associated Gas
Non-Associated Gas
Basic process of Gas Plants
Condensate
Sour Associated Gas
Sour Non-Associated Gas
Condensate
Stripper
Low Pressure
Amine
High Pressure
Amine
Acid
Gas
Sweet
Gas
Fluids produced from an oil well
are typically under pressure and
comprise oil, dissolved gas, salty
water and some hydrogen sulfide.
This mixture is sent to a gas-oil
separation plant (GOSP) for initial
processing. At the GOSP, a pressure
step-down process releases most
of the dissolved gas. A desalting
process then removes the salt
water. The resulting sour crude
oil is then sent for stabilization.
Inlet for oil/water/gas mixture
Sulfur
Recovery
Unit
Compression
Gas outlet
Water
Gas
Liquid
Sulfur
Dehydration
Foam
Oil
Cooling
Emulsion
Water
NGL
Recovery
Water outlet
Oil outlet
NGL
Sales Gas
In the gas plant, gas is received at slugcatchers, which separate condensate
and water from gas and capture
liquid ”slugs.“ These slugs, traveling
at high velocity, may damage piping
systems. Condensate liquids go to the
stripping section, where H2S and water
are removed. The separated sour gas
feed goes to the gas treating modules,
where, via contact with alkylamine,
the H2S and CO2 are stripped away,
creating sweet gas. The sweet gas is
compressed and chilled to separate
ethane and heavier gases. The H2Sand CO2-rich gas, now referred to as
acid gas, is sent to the sulfur plants
where H2S is converted to elemental
sulfur, recovered and made into solid
pellets for domestic and export sales.
appendix 185
184 appendix
Pipelines
Saudi Aramco operates a pipeline network nearly 20,000 kilometers long—roughly
equivalent to the flying distance between Rome and Sydney—including flow lines from oil and
gas wells, water injection pipelines and systems for refined products distribution. Major crosscountry pipelines include the Saudi Arabia–Bahrain Pipeline and the East-West Crude Oil and
NGL pipelines to Yanbu‘ on the Red Sea. The NGL pipeline linking Yanbu‘ and Shedgum is the
longest and most advanced gas line ever built—1,170 kilometers long.
Downstream
Downstream encompasses all the activities that occur after crude oil and gas
have been produced and initially processed. The fractionation of natural gas
liquids (NGL), the refining of crude oil and the petrochemical industry are
downstream activities. Shipping and distribution of crude oil and refined
products are also included within this scope.
OSPAS
The Oil Supply Planning and Scheduling (OSPAS) organization is the nerve center for the
movement of all of Saudi Aramco’s crude oil, natural gas and refined products. OSPAS plans,
schedules, coordinates and monitors the quantity—and quality—of millions of barrels of crude
oil every day of the year from the wellhead to company terminals.
OSPAS also tracks refined product movements from seven refineries, 19 bulk plants, 18 air
refueling sites, five strategic storage facilities and 1,600 kilometers of refined products pipeline.
It also tracks gas and NGL from six gas plants, three fractionation centers and more than 5,000
kilometers of pipeline. Saudi Aramco also operates 44 export berths at five marine ports, loading
millions of barrels of oil and refined products each day onto supertankers destined for ports in
the world’s three major energy markets: Asia, North America and Europe.
Within OSPAS, the “Big Board” of the Operations Coordination Center (OCC) tracks the
movement of oil, gas, NGL and refined products, and also oversees terminal operations and
electrical power distribution.
Operators in the Operations Coordination Center can, at a glance, see
the entire scope of the company’s
hydrocarbon production and distribution operations. With the click of a
mouse, operators can check the status
of individual pipeline valves, the feed
rate of a distillation column at a refinery,
the volume of a storage tank or the
loading status of a supertanker.
Terminals
Saudi Aramco’s enormous storage tank farms and shipping terminals supply crude oil,
NGL and refined products to customers around the globe. Every year, more than 9,000 tankers
call at company terminals at Ras Tanura and Ju‘aymah on the Arabian Gulf, and at Yanbu‘, Jiddah
and Rabigh on the Red Sea.
The Ras Tanura Terminal consists of the South Pier, the North Pier and the Sea Islands.
The South Pier, currently abandoned, is where Saudi crude oil was first loaded onto the
tanker D. G. Scofield in May 1939. The North Pier, connected to the mainland by a 1,200-meterlong causeway and trestle, operates six berths for the loading of crude oil, refined products and
refined liquid petroleum gasses (RLPG).
The Ras Tanura Sea Islands are a complex of man-made islands approximately 1½ kilometers
northeast of the North Pier. The four Sea Islands (one of which is decommissioned) each feature
a loading station for crude oil and bunker fuel (to power marine vessels) and two berths. Six
supertankers of up to 500,000 deadweight tons can load simultaneously.
In addition to linking wells to
processing plants, Saudi Aramco’s
pipeline system delivers crude oil,
gas, NGL and refined products to
domestic industries and utilities
and to company export terminals.
appendix 187
186 appendix
Refining
Crude oil is a mixture of hydrocarbon molecules, the simplest of which, methane, is
one carbon atom linked with four hydrogen atoms. The three principal groups of hydrocarbon
compounds that occur naturally in crude oil are paraffins, aromatics and naphthenes.
The refining process begins with the distillation, or fractionation, of crude oil into separate
hydrocarbon groups. Each hydrocarbon fraction has its own boiling point. The light fractions,
CH4– Methane (Natural Gas)
such as kerosene, have low boiling points while heavier fractions, such as fuel oil, have high
boiling points.
In the refining process, crude oil is heated in a distillation column, and the vapors resulting
from the boiling are drawn off and condensed. The fractions produced by a distillation column are
only the products that are in the crude oil to begin with—to produce more of a desired fraction,
such as gasoline, refineries must add conversion processes.
The earliest conversion process was thermal cracking, in which the heavy fractions of
crude oil are heated to a high temperature and the hydrocarbon molecules “cracked” to release
C 3H8– Propane
the lighter fractions, gasoline, for example. In visbreaking, residual (heavy oils leftover from the
distillation process) is heated, cooled with gas oil and rapidly burned or flashed. Visbreaking
reduces the viscosity of heavy oils and produces tar. Coking involves heating residual, but at
higher temperatures than visbreaking, until it cracks into heavy oil, gasoline and naphtha. The
heavy, almost pure carbon residue left behind is called coke and is also a commercial product.
Gas
Naphtha*
Reflux
Crude Oil Distillation Column
* For processing into gasoline or petrochemicals
** For further processing into jet fuel
Kerosene**
A crude oil loading line is lifted into
place aboard a supertanker calling
at the Ju‘aymah Offshore Terminal
in the Arabian Gulf.
The Ju‘aymah Offshore Terminal is a crude oil and bunker fuel loading facility designed
Light
Diesel Oil
for loading and topping off deep-draft tankers. The loading facilities are roughly 29 kilometers
north-northwest of Ras Tanura and 11 kilometers offshore. The largest supertankers afloat
C16H34– Diesel
take on cargo from six single-point moorings (SPM), each with a crude oil loading rate of up to
130,000 barrels per hour. There is also a two-berth RLPG loading facility at Ju‘aymah, accessible
from the shore via a 10-kilometer trestle.
Light fractions of crude oil, such as
methane and butane, are drawn from
the top of the distillation column,
while heavier molecules, such as diesel,
come from lower in the column.
Heavy
Diesel Oil
The Yanbu‘ crude oil terminal consists of four loading berths, two of which can be used
Furnace
simultaneously for a combined loading rate of 300,000 barrels per hour. Ships taking on cargo at
Yanbu‘ for Europe or North America can save about 7,400 kilometers (4,000 nautical miles) per
round trip, compared with sailing around the Arabian Peninsula from Ras Tanura or Ju‘aymah.
The Yanbu‘ NGL Plant has an associated two-berth RLPG terminal that can also handle
natural gasoline tankers. The nearby Yanbu‘ Refinery also has its own terminal, consisting of four
berths for loading fuel oil and marine diesel for cargo or bunker, motor diesel oil, regular and
premium gasoline, jet fuel, kerosene, naphtha and RLPG.
Fuel Oil
The Jiddah Terminal imports crude oil for the Jiddah Refinery and exports finished and
unfinished naphtha, kerosene, jet fuel, diesel, premium gasoline and fuel oil from four crude oil
and refined product berths and five bunker loading berths.
Steam
Saudi Aramco also operates smaller bulk plant marine terminals at Jazan and Duba.
Asphalt
Crude Oil
The fractional distillation of crude oil
is the first step in the refining process,
which yields a range of products, including petroleum gas (methane, ethane,
propane and butane); naphtha; gasoline; kerosene; gas oil or diesel distillate,
used to make diesel fuel and heating
oil; lubricating oil; fuel oil; and residuals
such as coke, asphalt, tar and waxes.
appendix 189
188 appendix
The Saudi Aramco Shell Refinery Co.
(SASREF), a joint venture between
Saudi Aramco and Shell, operates
this refinery complex in Jubail.
Catalytic cracking involves the use of a solid material, called a catalyst, mixed with the oil to help
Company (SATORP), a venture with Total of France, will be located in Jubail, and the Red Sea Refining
crack the heavier fractions. The process of hydrocracking adds high-pressure hydrogen gas to catalytic
Co., a subsidiary of Saudi Aramco, will be located in Yanbu‘. The third project is a company-owned
cracking, producing additional volumes of gasoline and other light fractions. Catalytic reforming uses
refinery and terminal in the Jazan region of southwestern Saudi Arabia. Internationally, Saudi Aramco,
a catalyst to combine low-weight naphtha into aromatics, which are used in blending gasoline and
through subsidiary offices, is a joint or equity venture partner in refineries in the United States, the
making chemicals.
Republic of Korea, China and Japan.
The various products from the distillation and cracking processes must be treated to remove
The Ras Tanura Refinery is the most complex refinery in the company’s domestic portfolio. The
undesirable compounds, such as sulfur, and to meet various performance and environmental specifica-
refinery includes facilities for crude oil stabilization and distillation, NGL processing, gas condensate
tions.
distillation, hydrocracking, visbreaking and catalytic reforming.
Saudi Aramco operates four domestic refineries, at Riyadh, Ras Tanura, Yanbu‘ and Jiddah,
and owns 50 percent of two domestic joint-venture refineries, with ExxonMobil in Yanbu‘ (SAMREF)
The Yanbu‘ Refinery is a hydroskimming plant, which is more complex than a topping refinery,
and it produces liquefied petroleum gas, gasoline, jet fuel, diesel oil and fuel oil, mainly for the domestic
and with Shell in Jubail (SASREF). Saudi Aramco also has a 37.5 percent stake in Petro Rabigh, with
market. The Jiddah Refinery features catalytic cracking and a catalytic reformer, and is a key supplier
Sumitomo Chemical Co. holding 37.5 percent and the Saudi public 25 percent. Work is also under
of fuel to the Jiddah and Makkah areas, especially during peak demand periods such as Ramadan and
way on three additional refining complexes. Two of the projects are 400,000-bpd full-conversion
Hajj. The Riyadh Refinery, like the Jiddah facility, contains a vacuum column, which permits processing
refineries integrated with petrochemical facilities: The Saudi Aramco Total Refining and Petroleum
of the heavier crude fractions. The Riyadh plant also features a hydrocracker and a catalytic reformer.
appendix 191
190 appendix
Gas Fractionation
Natural gas liquids recovered at the gas plants are sent to the NGL frac-
Distribution
In addition to the giant storage tank farms that feed shipping terminals with crude
tionation plants at Yanbu‘, Ju‘aymah and Ras Tanura for further processing. Typically, NGL plants
oil, NGL and refined products, Saudi Aramco operates a vast network of bulk plants and air fueling
receive ethane plus NGL in a combined feed from the gas plants via pipelines. The NGL is then
units strategically located throughout Saudi Arabia. Overall capacity of the company’s storage
pumped to the de-ethanizer columns in the fractionation modules, where the ethane is separated
facilities for all hydrocarbons is roughly 200 million barrels. Pipelines, marine crude oil tankers,
overhead as a vapor product. The ethane is sent to consumers as petrochemical feedstock or
product carriers and trucks are the principal delivery systems for the company’s petroleum and
injected into the sales gas system. The heavier gas at the bottom of the de-ethanizer column is
petroleum products.
fractionated in additional steps, yielding propane, butane, natural gasoline, hexane and pentane.
Through its 19 bulk plant operations, Saudi Aramco annually supplies around 375 million
Natural gasoline and pentane are blended and sent to refining, while the hexane and heavier
barrels of refined products to about 5,000 domestic bulk customers. Compliance reviews and
components are used as feedstock for petrochemical plants.
periodic spot checks are conducted to assist in maintaining product quality and to assure operations compliance with established safety and environmental policies and procedures.
Approximately 2,000 trucks are used to transport refined products over the Kingdom’s
150,000 kilometers of highways. The use of these trucks, which are subject to strict safety and
quality standards, is being minimized as Saudi Aramco replaces them with new pipeline systems.
Shipping vessels account for almost all of Saudi Aramco exports of crude oil, NGL and
refined products and are also used to transport hydrocarbons to supply and distribution facilities
on the Red Sea.
The company’s shipping subsidiary, Vela International Marine Limited, was established in
1984, when rights to Vela’s name and four existing tankers were acquired. Vela currently operates
a fleet of 17 very large crude carriers (VLCCs), each capable of carrying 2.1 million barrels of crude
oil. Vela also owns and operates five product tankers that perform coastal trade in the Red Sea
and the Arabian Gulf. Overall, Vela ships make roughly 1,000 voyages per year—83 percent of
which are international, with the remainder domestic—safely transporting roughly 2 million bpd.
The Master Gas System, which
handles more than 9 billion standard
cubic feet per day of gas, provides
fuel and feedstock to domestic industries, such as this plant in Jubail.
The sales gas (methane) system is extensive, covering large areas of Saudi Arabia from
coast to coast. Adding to its complexity is the integration and interdependence of the three main
systems: oil, gas and NGL.
The sales gas system depends greatly on oil production, since associated gas represents a
significant part of the system feed. It is also fully integrated into the NGL system, since any NGL
component recovered during processing causes a reduction in the sales gas supply. Sales gas is
piped to more than 54 industrial customers, including power, desalination and petrochemical
plants, throughout the Eastern, Central and Western provinces of Saudi Arabia.
The Ju‘aymah and Yanbu‘ gas plants receive ethane (C2) plus NGL, and Ras Tanura receives
propane (C3) plus NGL for fractionation and sweetening. The Ju‘aymah plant also receives C3 plus
NGL streams from the Berri Gas Plant and the Qatif and Abqaiq crude stabilization facilities. The
Ju‘aymah and Yanbu‘ gas plants produce ethane, propane, butane and natural gasoline products,
while the Ras Tanura Refinery produces all but ethane. The Ju‘aymah facility also has a depentanizer
column and associated facilities necessary for the delivery of a hexane (C6) stream to petrochemical
customers in Jubail. Propane is primarily used as petrochemical feedstock in the industrial cities of
Yanbu‘ and Jubail and the excess is exported. Butane is used as domestic petrochemical feedstock
and is also exported as a liquid. NGL products are used to produce more than 50 petrochemical
products and are sold to customers in more than 100 countries worldwide.
The Saiph Star, a doublehull crude oil carrier, joined
the Vela fleet in 2009.
appendix 193
192 appendix
Petrochemicals
The petrochemical industry traces its roots to World War II, when the demand
The next year, Saudi Aramco and The Dow Chemical Co. began exploring the possibility of
for synthetic materials rose due to shortages of, and lack of access to, natural resources. Before
building a petrochemical complex. The proposed joint venture, to be located in the Jubail industrial
the war, petrochemicals were an experimental sector: synthetic rubbers were developed in the
area, is perhaps the largest and most complex project in Saudi Aramco’s downstream portfolio.
early 1900s; Bakelite, the first petrochemical-derived plastic, in 1907; and polystyrene in the
The project proposal includes chemicals and plastics production units and an associated conversion
1930s. Today, petrochemicals are found in furniture, kitchen appliances, medical equipment,
park for local and foreign private-sector companies to build industries to use the products.
automobiles, airplanes and ships, soaps and detergents, solvents, drugs, fertilizers, pesticides,
computers, paints, epoxies, clothing and shoes, flooring and insulating materials, cosmetics,
luggage, and recording disks and tapes.
The final destination of most crude
oil is the fuel tank of a vehicle, whether
a motorcycle, car, truck, airplane or
train. Saudi Aramco exports of crude
oil power the transportation industries
in Europe, North America and Asia—
in this case, China.
Natural Gas
Crude Oil
NGL
Methane
Xylenes
Benzene
petrochemical products: olefins (mainly ethylene, propylene and the C4 derivatives, including
butadiene) and aromatics (benzene, toluene, xylene and naphthalene).
A significant proportion of the basic petrochemicals are converted into polymers: polyethylene,
polyvinyl chloride and polystyrene, all derived from ethylene, and polypropylene, derived from
propylene. Polymers are used in plastics, synthetic rubbers and synthetic fibers, such as polyester,
nylon and acrylic.
Beginning in the 1990s with a series of international joint and equity ventures in refining and
marketing, Saudi Aramco has been transforming itself from a crude oil producing and exporting
company into an integrated petroleum enterprise, with activities all along the value chain. The
Ethane
C4 box*
Propylene
Ethylene
Olefins
Xylenes
Toluene
Benzene
Pygas
C4 box*
Propylene
Ethylene
Solvents, dyes, fibers
and films used in
products such as
polyester fibers
and plastics and in
plasticizers, substances that make
plastics more flexible and are used
in medical tubing
and blood bags,
toys and footwear.
Industrial chemicals
used in coatings,
sealants, adhesives,
paints and the foam
used in furniture,
bedding, car seats
and building
insulation.
Plastics used in boats,
cars, computers, food
containers and packaging, construction
materials, nylon, toys,
carpets, shampoo,
cleaning products,
emulsifiers and
pharmaceuticals.
Used for gasoline
blending or as
feedstock.
Synthetic rubbers
and plastics used in
such products as
automotive parts,
tires, aviation gasoline and the gasoline
additive MTBE.
Resins, fibers and
plastics used in
such products
as detergents,
solvents, varnishes,
super-absorbent
materials, acrylic
fibers, pharmaceuticals, cosmetics and
food packaging.
Plastics, polyesters
and synthetic rubber
used in products
such as luggage,
appliances, automotive parts, footwear,
flooring and tires.
most recent development in the company’s transformation is the petrochemical sector. The
goal is to create more value from Saudi Arabia’s hydrocarbon resources, principally by bringing
petrochemicals processing and manufacturing to the Kingdom rather than exporting commodity
petrochemicals
petrochemicals to foreign markets where they are used in associated industries.
The petrochemical industry converts
crude oil and natural gas into basic
petrochemical building blocks that,
in turn, are used to produce consumer
goods ranging from heart valves
to raincoats.
Pygas
LPG
a r o m at i c s
among others. These feedstocks are then further cracked to create the basic building blocks for
Toluene
Methane
Petrochemical facilities receive their raw material, known as feedstocks, from refineries
and NGL and gas plants. Feedstocks include ethane, naphtha, propane, butane and hexane,
Associated
Gases
Naphtha
In March 2006, Saudi Aramco and Sumitomo Chemical Co. of Japan broke ground on the
Petro Rabigh joint venture, one of the world’s largest integrated refining and petrochemical facilities.
The complex commenced operations in early 2009 and has the capacity to produce 18.4 million
tons of high-value petroleum products and 2.4 million tons of ethylene- and propylene-based
petrochemical derivatives per year. An associated industrial city will use the materials produced by
Petro Rabigh to manufacture a wide range of products for local and international consumption.
*Butylene, butadiene
and derivatives
appendix 195
194 appendix
Safaniya
Jubail
Tanajib
Nariya
Ju‘aymah
Ras Tanura
Qatif
Dammam
Dhahran
Khursaniyah
Berri
iraq
Operations Data
Domestic Operations Map
■
International Operations Map
■
Oil and Gas Operations
■
Production and Workforce History
Shedgum
Turaif
Badanah
jordan
■
Abqaiq
al-Jawf
al-Hasa
Khurais
Sakaka
Dawmat
al-Jandal
kuwait
Hafar al-Batin
Qaisumah
Tayma
Duba
‘Udhailiyah
‘Uthmaniyah
Rafha
Tabuk
al-Wajh
Qurayyah
Safaniya
Tanajib
Hayil
Haradh
al-Khafji
Jubail
Nariya
al-‘Ula
Buraydah
Ras Tanura
Qatif Dammam
Abqaiq
Dhahran
Hofuf
al-Zilfi
‘Unayzah
Khaybar
al-Hasa
Yanbu‘
il pi pel ine
Riyadh
crude o
east-west
al-Dawadimi
ine
al-Kharj
ngl pipel
east-west
Madinah
Khurais Hawiyah
Salwah
Haradh
saudi arabia
united arab
e m i r at e s
Rabigh
Layla
Jiddah
Makkah
Tayif
oman
al-Sulayyil
al-Bahah
Bishah
Tathlith
Abha
Khamis Mushayt
Najran
ash-Sharawrah
Jazan
yemen
d o m e s t i c o p e r at i o n s
key
Towns
d o m e s t i c r e f i n e ry
major crude oil pipeline
C a p i ta l
j o i n t / e q u i t y v e n t u r e r e f i n e ry
major ngl pipeline
s e a w at e r t r e at m e n t p l a n t
crude oil terminal
trans-Arabian pipeline
gas processing plant
refined products terminal
S h ay b a h - a b q a i q p i p e l i n e
I n t e g r at e d r e f i n e r y a n d
petrochemical plant
domestic refined products terminal
major oil processing complex
domestic refined products
d i s t r i b u t i o n fa c i l i t y
ngl terminal
oil field
gas field
scale in kilometers
0
200
appendix 197
196 appendix
>S-Oil Corporation
Seoul
republic
of korea
>Saudi Petroleum
Overseas Ltd.
>Aramco
Overseas
Company B.V.
London
Toyko
>Saudi Petroleum Ltd.
>Aramco Overseas
Company B.V.
>Showa Shell Sekiyu K.K.
j a pa n
The Hague | Aramco Overseas Company B.V.
Rotterdam
>Texaco Esso AOC Maatschap
>TEAM Terminal B.V.
at l a n t i c O c e a n
Saudi
Petroleum Ltd.
Beijing
> Aramco
Overseas
Company B.V.
New Delhi
Aramco Overseas Company B.V.
Shanghai
> Fujian Refining and
Petrochemical Co. Ltd.
Pa c i f i c O c e a n
> Sinopec SenMei (Fujian)
Petroleum Co. Ltd.
Fujian
Okinawa
Hong Kong
> Aramco Overseas Company B.V.
> Saudi Aramco Sino Co. Ltd.
New York City
Saudi Petroleum International Ltd.
Washington, D.C.
Aramco Services Company
Singapore
Saudi Petroleum Ltd.
indian Ocean
u n i t e d s tat e s
> Aramco Services Company
> Saudi Refining Inc.
> Motiva Enterprises LLC
Sidi Kerir
Houston
Ain Sukhna
SUMED Arab
Petroleum
Pipelines Co.
LOOP
Aramco Gulf
Operations Co. Ltd.
al-Khafji
> Luberef
> Saudi Aramco Mobil
Refinery Co. Ltd. (SAMREF)
> MARAFIQ
Yanbu‘
> MARAFIQ
Jubail | > Saudi Aramco Shell
Refinery Co. (sasref)
Dhahran
Ju‘aymah
Ras Tanura
Rabigh | Petro Rabigh
Thuwal
saudi arabia
Jiddah
> Luberef
> Jiddah Oil Refinery Co.
i n t e r n at i o n a l o p e r at i o n s
key
Towns
Saudi Aramco Headquarters
a f f i l i at e , s u b s i d i a r y o r
joint/equity venture
long-term storage and
t e r m i n a l fa c i l i t i e s
m a r a f i q : E l e c t r i c i t y a n d W at e r
U t i l i t y f o r J u b a i l a n d Ya n b u
‘
Luberef: Saudi Aramco
L u b r i c at i n g O i l R e f i n e r y C o .
loop: Louisiana offshore oil port
lightering areas
ports
p r i n c i pa l e x p o r t r o u t e s
v e l a s h i pp i n g r o u t e s
Dubai
Vela International
Marine Limited
appendix 199
198 appendix
Abu
Hadriya
Zuluf
Qatif
Shaybah
Khursaniyah
Ghawar
Berri
Marjan
Abu Sa‘fah
Safaniya
Berri
Abqaiq
Khursaniyah
Haradh
Hawiyah
Harmaliyah
Qatif
Qatif
‘Uthmaniyah
Shedgum
Ras Tanura
Abqaiq
Hawiyah
Yanbu‘
Jubail
Abqaiq
Tapline
MARAFIQ
Dhahran
Tanks
Jubail***
Ras Tanura
Khurais
Bahrain*
Ras Tanura
Ju‘aymah
Yanbu‘
Ras Tanura
Ju‘aymah
Yanbu‘
Central
Arabian
Fields
Yanbu‘
Ras Tanura
Ju‘aymah
Riyadh
Yanbu‘**
Petro
Rabigh
Jiddah
SWCC
MARAFIQ
key
g a s o p e r at i o n s
o i l o p e r at i o n s
The crude oil produced by Saudi Aramco
from both onshore and offshore fields
first goes to gas-oil separation plants for
removal of gases, water and salt, after
which it is sent for further processing
at stabilizers or refineries. Most of
the crude oil is delivered to tankers at
Ras Tanura, Ju‘aymah or Yanbu‘.
key
oil Field
r e f i n e ry
gosp: gas-oil
s e pa r at i o n p l a n t
i n t e g r at e d r e f i n e r y a n d
petrochemical plant
s ta b i l i z e r
plant
terminal
Local customer
*The refinery in Bahrain is not
a Saudi Aramco facility.
**Two Yanbu‘ refineries
(one joint venture)
*** Joint venture
Gas produced with crude oil is
collected from gas-oil separation plants
and fed to gas processing plants. There,
impurities are removed, hydrogen
sulfide is recovered for conversion into
elemental sulfur, and sweet, dry gas is
extracted for use as an industrial fuel or
feedstock. From gas processing centers
at Shedgum, Hawiyah, Khursaniyah and
‘Uthmaniyah, NGL (natural gas liquids)
and ethane are piped to plants at
Yanbu‘ and Ju‘aymah for fractionation.
After removal of the ethane, the NGL is
further fractionated into LPG (propane
and butane) and natural gasoline.
Gas produced independently of crude
oil (non-associated gas) is processed at
the Haradh and Hawiyah gas plants
for delivery into the sales gas system.
The Hawiyah NGL Plant processes
sweet gas from the Hawiyah and
Haradh gas plants. NGL from the
Berri Gas Plant goes to Ju‘aymah or
Ras Tanura for fractionation. LPG is
exported from Yanbu‘ and Ju‘aymah.
From the fractionation plants,
ethane is delivered to the industrial
complexes at Yanbu‘ and Jubail for
use as a petrochemical feedstock.
n o n - a s s o c i at e d
gas wells
gosp: gas-oil
s e pa r at i o n p l a n t
Gas Plant
marafiq:
electricity
a n d w at e r u t i l i t y
for jubail and
ya n b u
‘
N G L : n at u r a l g a s
liquids plant
swcc: saline
w at e r c o n v e r s i o n
c o r p o r at i o n
industrial complex
terminal
f r a c t i o n at i o n p l a n t
o t h e r i n d u s t ry
saudi electric
c o m pa n y
Average daily production
of crude oil and NGL
s a u d i a r a m c o p r o d u c t i o n h i s t o ry
1 9 3 8 – 2 0 1 0 (thousands of barrels)
key
crude oil
N at u r a l G a s L i q u i d s
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
1955
1954
1953
1952
1951
1950
1949
1948
1947
1946
1945
1944
1943
1942
1941
1940
1939
1938
6,826.94
141.42
8,343.95
184.78
9,016.95
219.45
8,066.11
253.11
9,251.08
309.26
9,631.37
369.23
9,623.83
448.17
6,327.22
429.50
4374.30
330.10
3,922.08
355.07
3,041.10
316.31
4,689.80
304.18
3,991.00
344.92
4,928.10
416.21
4,863.53
420.95
6,257.56
533.23
8,053.40
586.74
8,156.57
622.06
7,854.74
639.76
7,833.28
687.93
7,807.63
731.85
7,864.83
756.15
7,751.93
767.45
8,006.24
764.83
7,274.05
737.35
7,800.07
778.71
7,570.64
801.05
6,792.32
868.32
8,103.45
945.43
8,610.58
1,058.14
9,064.62
1,096.94
8,912.17
1,093.24
8,531.91
1,081.00
8,924.14
1,098.92
7,912.56
1,123.96
7,910.20
1,219.30
1,520.70
2.90
1,629.02
5.80
1,716.11
11.01
2,024.87
13.87
2,392.74
15.56
2,597.56
20.40
2,829.98
38.47
2,992.66
46.17
3,548.87
52.12
4,497.58
52.07
5,733.40
54.07
7,334.65
97.12
8,209.71
137.63
1,392.52
1,247.14
1,095.40
1,015.03
992.11
986.13
965.04
953.00
844.64
824.76
761.54
546.70
476.74
390.31
246.17
164.23
58.39
21.30
13.34
12.41
11.81
13.87
10.78
1.36
200 appendix
appendix 201
key
saudi
e x pat r i at e
t o ta l w o r k f o r c e
s a u d i a r a m c o w o r k f o r c e h i s t o ry
1 9 3 5 – 2 0 1 0 ( at y e a r - e n d )
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
1955
1954
1953
1952
1951
1950
1949
1948
1947
1946
1945
1944
1943
1942
1941
1940
1939
1938
1937
1936
1935
48,053
7,013
47,741
7,057
10,636
3,334
12,432
4,390
14,931
5,451
15,187
6,543
16,740
8,787
17,894
16,755
21,839
20,413
26,321
24,260
29,753
27,885
33,067
28,165
34,226
24,736
34,882
23,273
33,382
18,209
31,906
13,958
31,623
12,555
32,085
12,399
31,712
12,216
32,106
11,582
32,900
12,948
33,847
13,008
34,615
14,107
44,938
12,548
46,180
11,596
12,216
5,408
46,133
10,347
46,172
9,360
45,586
8,490
46,315
8,186
45,869
8,208
46,496
7,991
46,365
7,589
45,505
7,015
44,991
6,852
44,702
6,654
45,464
6,629
47,502
6,939
115
26
1,076
62
548
54
2,745
340
3,178
463
2,668
382
1,647
193
1,654
171
2,692
190
7,585
1,475
8,087
3,379
7,297
2,684
12,018
4,879
12,226
7,379
10,026
6,099
10,767
6,734
13,786
8,852
14,819
10,273
14,051
9,393
14,665
8,782
13,844
8,091
13,671
7,535
13,222
6,635
12,572
6,076
12,216
5,408
11,660
4,296
11,442
3,558
11,341
3,124
10,892
2,998
10,805
2,999
10,793
2,958
10,761
2,848
10,294
2,678
9,894
2,483
9,438
2,213
9,133
2,099
9,109
2,225
9,590
2,575
54,798
55,066
54,441
52,093
51,356
51,843
52,520
53,954
54,487
54,077
54,501
54,076
55,532
56,345
56,480
57,776
57,486
48,722
46,855
45,848
43,688
43,928
44,484
44,178
45,864
51,591
58,155
58,962
61,232
57,638
50,581
42,252
34,649
25,527
21,730
20,382
16,822
13,970
12,165
11,334
11,232
11,651
12,377
12,972
13,609
13,751
13,804
13,890
14,465
15,000
15,956
17,624
18,648
19,857
21,206
21,935
23,447
23,444
25,092
22,638
17,501
16,125
19,605
16,897
9,981
11,466
9,060
2,882
1,825
1,840
3,050
3,641
3,085
602
1,138
141
202 appendix
appendix 203