ghawar fall 08
DESCRIPTION
Oil FieldTRANSCRIPT
Left top: A July 25, 1948, lab report strongly indicated the presence of hydrocarbons. Left middle: A June 12, 1951, flow-test report onGhawar’s first well at ’Ain Dar was very promising. Left bottom: Legendary Bedouin guide Khamis bin Rimthan was instrumental in guiding Aramco geologists to potential well sites throughout the Eastern Province. Above: a map showing the location of Ghawar“discovery” wells west of the Arabian Gulf.
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22 Saudi Aramco Dimensions
The debut discoveries, following the signing of an
exploration concession agreement between Saudi Arabia
and Standard Oil Of California (Socal) in 1933, were
at Dammam (1938), Abu Hadriyah (March 1940) and
Abqaiq (December 1940).
These successes led in less than a decade to the astound-
ing realization that a number of
apparently independent, commer-
cially viable oil fields were, in
fact, all part of one mind-bending
mega-field — Ghawar.
Ghawar is divided into five
areas, discovered individually:
’Ain Dar (1948), Haradh (1949
— located in the southernmost
part of the field), ‘Uthmaniyah
(1951), Shedgum (1952) and
Hawiyah (1953).
The giant reservoir is 280 kilo-
meters long and 40 km wide,
encompassing 1.3 million acres.
Saudi Aramco continues to pump
about 5 million barrels of Arabian
Light crude oil from Ghawar
reservoirs every day. It also pumps
2.5 billion cubic feet per day (cfd)
of natural gas from the field in
association with the production
of oil, and another 4 billion cfd
of non-associated gas, produced
from independent gas reservoirs
beneath but not part of Ghawar’s
oil-bearing formations.
So, by all measures, Ghawar
— the “crown jewel” for Saudi
Aramco and the Kingdom —
is an awesome asset.
Ghawar has all the right stuff to
be a super producer: high porosity
of its reservoir rock, which means
there’s an abundance of rock pores, or spaces, for holding
oil; high permeability, meaning many natural channels
allowing oil to flow through the rock; valuable light rather
than heavy oil; and high recovery potential.
The original realization of Ghawar’s existence was
a kind of educated hunch.
In 1940, while the Abqaiq
prospect was being drilled, a
young geologist — Ernie Berg
— was spending his second field
season mapping adjacent quad-
rangles on the edge of the great
Rub‘ Al-Khali desert, or “Empty
Quarter.” Berg mapped the dry
river bed known as Wadi Sahaba
in the Haradh area and noticed
that it took a sharp turn to the
south from its normal east-west
course for no reason apparent
to the naked eye.
After measuring and plotting
a large enough area to see a
trend, it became apparent that
the wadi was diverted by a
broad, low-relief dome, the sur-
face expression of a much larger
subsurface dome or anticline.
Aramco geologist Max Steineke,
who was the driving force behind
the company’s first commercial
discovery two years earlier at
Well No. 7 in Dammam, came
into camp the next day and
agreed with Berg that the
Haradh structure was poten-
tially significant.
In fact, it turned out that
Berg’s map was the first to delin-
eate a structure in the Ghawar
field and was therefore what
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Above: Saudi Arabia’s King Abdulaziz Al Saud ushered in atransformational era by fully sup-porting the search for oil in hisKingdom starting in 1933. Topleft: Ernie Berg, at right, with fel-low geologist Tom Barger in the1930s, is credited with discover-ing the desert outcrops thathinted at giant Ghawar’s exis-tence. Middle left: ’Ain Dar No. 1,an early production well. Bottomleft: a desert exploration party inthe Ghawar area in the 1940s.
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Legendary Aramco geologistMax Steineke, above, backed the intuitions of fellow geolo-gist Ernie Berg that ultimatelyproved well-founded, as a seriesof seemingly independent fieldsproved to be one giant field,Ghawar. Top right and middle:Aerial views of ‘Udhailiyah, thenthe new base for South Ghawarfield operations, 1956. Bottomright: the Ghawar field’sHawiyah Gas Plant, 1999.
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geologists would call the “discovery map” for that field. With
the onset of World War II, the difficulties of getting supplies
and the loss of men to the war effort, wildcat drilling was
suspended. However, a shallow-drilling campaign designed
to confirm geologic structures based on Berg’s and other geol-
ogists’ maps was continued. The shallow drilling confirmed
Berg’s subsurface anticline at Haradh and was continued
northward, confirming a continuous anticline stretching from
Haradh to ’Ain Dar and Shedgum. This anticline was dubbed
the En Nala anticline, meaning “The Slippers.”
After World War II and with the resumption of drilling,
the most obvious location to resume wildcat drilling was
the ’Ain Dar structure because of its proximity to producing
facilities at Abqaiq. ’Ain Dar No. 1 was completed in July
1948 and put on production in early 1951 at an extraordi-
nary rate of 15,600 barrels per day (bpd) of dry oil, mean-
ing without water contamination. ’Ain Dar No. 1 was a
significant discovery for Aramco, but nobody knew how
significant it would become.
Although a number of structures with apparent closure
had been delineated, and at least ’Ain Dar had proven to be
oil-filled, nobody openly suggested that the En Nala anticline
would prove to be one continuous field. Aramco engineers
wanted to drill a step-
out well, ’Ain Dar No.
2, about 12 km south
of ’Ain Dar No. 1, but
Steineke argued that
the next well should
be 185 km to the
south on the Haradh
structure first mapped
by Ernie Berg nine
years earlier. Steineke
prevailed.
Haradh No. 1 was
a successful wildcat
drilled in 1949. Next
came ‘Uthmaniyah
No. 1, which was
drilled in 1951. The Shedgum No. 1 discovery well was
drilled in 1952, followed by Hawiyah No. 1 in 1953. ’Ain
Dar No. 1, Shedgum No. 1, Haradh No. 1 and Hawiyah
No. 1 are still producing today.
These discoveries pointed toward the existence of one
continuous reservoir with a common oil/water contact,
which was designated as Ghawar Field in 1952.
Ghawar — the Bedouin originally called the pasturage
area “El Ghawar” — remains the largest single oil field on
Earth. Not only is Saudi Aramco getting most of its daily
oil production from Ghawar but also most of its daily raw-
gas feed.
The field’s production reached a zenith of 5.7 million
bpd by 1981 — a world record for continuous production
in a single field — but output was reduced later that decade
due to declining demand. Still, the field’s current, sustained
5 million bpd output is unrivaled.
Since its discovery, enormous Ghawar has kept oil ex-
perts on their toes. In mid-2007, the Ghawar Integrated
Assessment and New Technology (GIANT) team, an inter-
departmental group working on a long-term, visionary
endeavor to better understand and characterize the oil field,
came across an interesting finding while looking at ways
to maximize the
reservoir’s oil recov-
ery percentage. The
researchers found an
extensive micro-pore
system of hidden
passages in carbon-
ate rock, where a sig-
nificant percentage
of unrecovered oil
resides. Today, the
GIANT team is ana-
lyzing this newfound
potential and finding
ways to tap into the
as-yet untapped
world below. ■
Chart above shows the accumulative oil production over the years ofGhawar’s five discovery wells.
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After World War II and with
the resumption of drilling, the
most obvious location to re-
sume wildcat drilling was the
’Ain Dar structure because of its
proximity to producing facilities
at Abqaiq. ’Ain Dar No. 1 was
drilled in 1948 and flowed oil to
the surface during drillstem testing.
’Ain Dar No. 1 was put on
production in early 1951 at an
extraordinary oil rate of 15,600
barrels per day (bpd) — and is still
producing today more than 57 years
later, with the original well casings
and with the aid of best-in-class
reservoir management practices.
The well, amazingly, produced
“dry oil” for 49 years, before pro-
ducing its first water in 1999. Over
the years, this magnificent well has
produced 152 million barrels of oil
and is still producing 2,100 bpd
in 2008.
In 1949 Aramco engineers wanted
to drill a step-out well, ’Ain Dar
No. 2, about 12 km to the south
of ’Ain Dar 1; instead, a second
wildcat was drilled 185 km to the south at
Haradh. At that time, no one openly suggested that
the En Nala anticline would prove to be one con-
tinuous field. This possibility became very real
when the Haradh No. 1 wildcat struck oil in 1949.
However, because Haradh well was nearly
200 km south of ’Ain Dar production facilities
and therefore impractical to produce at the
time, Aramco had to wait 15 years to bring
it on-stream. In 1964, Haradh No. 1 was
finally put on production at an oil rate of
6,400 bpd. The well was shut in during the
mid-1980s due to low demand but resumed
production in 1990 at 6,700 bpd of dry
oil, after acid stimulation. Haradh No. 1
has produced more than 24 million bar-
rels of oil in its career, and continues to
produce in 2008 at an oil rate of 2,300
bpd with a watercut of only 1 percent.
‘Uthmaniyah No. 1 was important in establish-
ing that the En Nala anticline was oil-filled between
’Ain Dar and Haradh. This wildcat well was drilled
in 1951 and tested initially at 9,200 bpd. As with
the other Ghawar wells, oil gravity was in the range
of 33 degrees API (Arabian
Light Crude).
‘Uthmaniyah No. 1 was
brought onstream in 1956
and produced at an oil rate
of 11,300 bpd in its first
year. Located on the eastern
flank of ‘Uthmaniyah, this
well was the first of the
discovery wells to employ
a water shutoff to extend
dry oil production. This
discovery well has pro-
duced more than 20 mil-
lion barrels of oil.
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The Shedgum No. 1 discovery well was drilled
in 1952 to delineate the En Nala anticline to
the east of ’Ain Dar. The well struck oil in
the Arab-D carbonate and was later brought
on-stream in 1954 at an outstanding oil pro-
duction rate of 12,400 bpd, comparable to
’Ain Dar No. 1.
In 1968 the wellbore rock matrix was
acidized to improve the flow of oil from the
carbonate formation. In 1989 liners were
run across the open hole to proactively
address future water encroachment.
Recently, the oil production rate
was enhanced greatly for Shedgum No. 1
by recompleting the well with a horizon-
tal sidetrack complemented by inflow con-
trol device (ICD) technology. Not only was
the oil rate increased from about 1,000 bpd
to over 3,700 bpd, the watercut has also
been lowered significantly.
Shedgum No. 1 has produced more than 98
million barrels of oil over the last 55 years, and
the application of new technologies will keep
the well producing for years to come.
The final discovery well was Hawiyah No. 1,
which confirmed that Ghawar held oil be-
tween ‘Uthmaniyah and Haradh. Drilling
was completed in 1953, and the well came
on-stream in 1966 at 4,800 bpd of dry oil.
The well received an acid stimulation
treatment in 1977, with subsequent pro-
duction of 7,600 bpd. Hawiyah No. 1
has produced 51 million barrels of oil, and
continues to produce today at 4,600 bpd.
Since the discovery of the Ghawar field in
1948, Saudi Aramco has implemented
best-in-class field management practices
and leading technologies that have
evolved over the years. As a result,
Ghawar’s “magnificent five” discovery
wells have demonstrated extraordinary
performance with extended lifecycles and
outstanding oil recovery.
One of the first reservoir management
initiatives was gas re-injection in ’Ain Dar.
In 1958, King Sa’ud Ibn ‘Abd al-Aziz inau-
gurated the Gas Injection facilities in ’Ain
Dar. The primary purpose of this program
was to re-inject produced gas to sustain reser-
voir pressure. Gas injection commenced in
1959 and continued for 20 years.
Water injection began in Ghawar in 1964
to provide additional pressure support (i.e.
maintaining reservoir capacity to push oil
to the surface). This technology, known as
secondary recovery, provided a stepwise
improvement in pressure support, and
began the displacement of oil from the
outer edges of the Ghawar field toward
the central regions to sustain oil produc-
tion, as demonstrated by the phenomenal
performance of the discovery wells.
In 1995, a comprehensive 3-D seismic
campaign was conducted across the
Ghawar field. The seismic profiles pro-
vided vital information on
reservoir structure and distri-
bution of fractures, guiding
development and re-comple-
tions across Ghawar. This
information, for example, was
used in guiding the placement
of the horizontal well trajectory
for Shedgum No. 1.
The Ghawar discovery wells
are still producing today with
their original well casings. This
highlights the outstanding quality
of workmanship and materials.
Combined, the five Ghawar dis-
covery wells have produced nearly
350 million barrels of oil.
The discovery wells will con-
tinue producing oil, and at the
appropriate time Saudi Aramco will apply the latest best-in-
class technologies to further extend producing life and curtail
water production. ■
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(1) 1948 Letter to His Excellency Finance Minister Abdullah Sulaiman reporting that wildcat well ’Ain Dar No. 1 successfully flowed oil to the surface. (2 through 5) Original well completion drawings for Haradh No. 1, ‘Uthmaniyah No. 1,Shedgum No. 1 and Hawiyah No. 1. (6) The original Hawiyah No. 1 well resistivity log showing large oil column.
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