The document summarizes the petroleum resources of Yemen. It outlines that Yemen has significant oil and natural gas reserves, with proven oil reserves of 4 billion barrels and natural gas reserves of 16.9 trillion cubic feet. The majority of reserves are located in two basins - the Sab'atayn Basin in the north and the Say'un Al-Masila Basin in the south. Key producing regions and blocks within these basins are discussed, along with production levels and operating companies. The main productive formations and their characteristics are also summarized.

1. The Republic of Yemen Petroleum Overview
Nedham Mohammed Darsi*
(Earth Science College of Jilin University, 130026, P. R. China)
Abstract Yemen located on the southwest corner of the Arabian Peninsula. It is
known that Yemen is important to world energy markets because of its oil and natural
gas resources as well as its strategic location at the Bab el-Mandab strait linking the
Red Sea and the Gulf of Aden. Due to the Ministry of Oil and Mineral Resources
(MOMR, 1998E) the Yemeni Oil Production was estimated to be 385,000 barrels per
day (bbl/d), Oil Consumption was 69,000 bbl/d and Net Oil Exports was 316,000
barrels per day (bbl/d). On 1999 the Yemeni Proven Oil Reserves was estimated to be
4 billion barrels and the Natural Gas Reserves was estimated to be 16.9 trillion cubic
feet (Tcf) (Ministry of Oil and Mineral Resources, 1/1/99). At this time, many
researchers, scientific expeditions and foreign companies are interested in Yemen.
This paper discussed the petroleum overview of the Republic of Yemen. In my
opinion, Yemen is not just going to attract all with its oil and gas discoveries in the
near future, but also with its new geological data and information.
Introduction
The oil and gas reserves of the Republic of Yemen were estimated at 1.738
billion (B) barrels of oil in place (Proven recoverable reserves) and about 16.7 trillion
cubic feet (Tcf) of gas. (The Yemeni Ministry of Oil and Mineral resources; 1998E,
1999)
The Republic of Yemen is highly in need of Oil and Gas for internal use and
for exporting to get the revenue. Therefore, the government had taken effective
measures to encourage local and foreign investment in the field of exploration of
hydrocarbon resources. The basis of exploration lies on the production sharing
agreements.
Based on the aeromagnetic, gravity and seismic survey and on deep drilling,
the experts in the Petroleum Exploration and Production Board (P.E.P.B) had divided
the interesting areas into blocks for exploration of Oil and Gas. (See, Fig. 1)

2. Fig. (1) The Concession Map of the Republic of Yemen
Legend:
Block 18, Marib, Al-Jawf Area, Sab’atayn Basin
Block 5, Marib, Shabwa Area, Sab’atayn Basin
Block 4, Shabwa Area, Sab’atayn Basin
Block 10A, East Shabwa Area, Sab’atayn Basin
Block 14, Al-Masila Area, Sab’atayn Basin
1.Oil and Natural Gas in Yemen
Oil is the main source of income, which stood at output of 385,000 barrels per
day (bbl/d) for 1998. It expects to increase to 500,000 bbl/d (Proven oil reserves is 4
billion barrels).
Yemen also has considerable potential as a natural gas producer and exporter,
with natural gas reserves of 16.9 trillion cubic feet (Tcf). The bulk of Yemen's gas
reserves are concentrated in the Marib-Jawf fields, operated by the Yemen
Exploration and Production Company (YEPC).
The above mentioned Oil and Gas reserves in the Republic of Yemen are
housed in about 14 onshore fields and discoveries located in two main groups:
(1) The first group located in the Marib-Al-Jawf-Shabwa area (Sab’atayn rift
basin), where 11 fields are discovered. (Fig. 1; Block 18, 5, 4, 10A and
Fig. 2)

3. (2) The second group located on the Tertiary plateau north of Mukalla and
south of Wadi Hadramawt-Masila (A part of Say’un Al-Masila basin),
where three fields with oil in place estimated at 550 MM barrels are
discovered. (Fig. 1; Block 14 and Fig. 2)
1
6
3
4
9 10
9
6 6
5 3
2
8 5
9
7
9
2
5
LEGEND
6. Intra-Basinal Highs
1. Paleozoic Basins
7. Cretaceous Basement
2. Jurassic Basins
(Thin Sedimentary Cover)
3. Jurassic / Cretaceous Basins 8. Volcanics
9. Basement
4. Cretaceous Basins
10. Fault
5. Tertiary Basins
Fig. (2) Sedimentary Basin Map of the Republic of Yemen
(Nedham, M.Darsi, 2001; after As-Saruri and Baraba, 1995)

4. 2. The Main Productive Regions
The largest producers are Canadian Oxy Company (Working in Al- Masila
area; Say’un Al-Masila Basin) and Hunt Oil Company (Working in the Marib- Al-
Jawf area; Sab’atayn Basin), accounting for 340,000 BOPD). The Commercial Oil
Discoveries were achieved in the following basins/blocks:
2.1 Say’un Al-Masila Basin:
2.1.1 Al-Masila Block 14:
(550 million barrels) in the south, operated by Canadian Occidental Petroleum
Company (CanOxy). It is the most productive oil field. Currently the oil production
only from Masila Block 14 is reaching 200,000 BOPD.
IMPORTANT NOTICE (1):
Produced oil in this basin is primarily from the Lower Cretaceous Qishn Clastics
Member sandstone, which is sourced by the Upper Jurassic Madbi Formation (Shale +
Limestone rocks), sealed by inter bedded shales and the tight carbonates at the top of
the Qishn Cretaceous (Mills, 1992) and trapped by Paleo-Horst Traps Type. Here, I
would like to give a brief on the Cap, Source and reservoir rocks characteristics
of this area:
(1) Qishn Carbonate Member: (Barremian to Aptian /? Lower Albian age)
Good Cap Rocks in Say’un Al-Masila Basin.. A main section of
Limestone-Mudstone to Limestone-Wackstone with thins streaks of Shale.
(2) Qishn Clastic Member: (Hauterivian to Lower Barremian /? Lower
Aptian age in the West) It’s the main target and the main primary reservoir
rocks in Say’un Al-Masila Basin. A main section of Sandstone, streaks of
Claystone and traces of Anhydrite (with a logged trace of Coal)
(3) Madbi Formation: (Lower Kimmeridgian to Lower and Middle
Tithonian) It is the main source rock in the Republic of Yemen, it’s made
up of marls (often bituminous) with shales and silty horizons and local
gypsiferous units. Thin interbeds of marly and fossiliferous limestones also
occur. This formation contains a rich benthonic and nektonic fauna of
bivalves, brachiopods, ammonites and belemnites suggesting slightly
deeper shelf environments
(4) Kohlan Formation: (good reservoir characteristics) Lower-Middle
Jurassic age (It’s lower part thought to be of Triassic (?)- Malm age). It has
an average thickness of ca. 70m.; it comprises sandstones and
conglomerates transgressively overlying Precambrian basement or
Paleozoic rocks.

5. 2.2 Sab’atayn Basin:
2.2.1 Marib-AL-Jawf Block 18:
(490 million barrels) in the north, operated by Yemen Hunt Oil Company.
Now the production is reaching 140,000 BOPD.
IMPORTANT NOTICE (2):
Produced hydrocarbons from Upper Jurassic sandstone (Alif Formations),
which are sourced from Upper Jurassic organic-rich units (Madbi Formations) and
mainly sealed by evaporates (Safer Formation) Maycock, 1987; Huurdeman et al.,
1989; Schlumberger, 1992). Listric type Traps (Jurassic).
2.2.2 The Jannah Block 5:
(345 million barrels) Produce at 25,000 bbl/d, (The operator is Hunt/Jannah
Oil Company).
IMPORTANT NOTICE (3):
(See the above mentioned Important Notice No.2).
2.2.3 East Shabwa Block 10A:
(180 million barrels) operated by Total Oil Company. Production is reaching
20,000 BOPD and is expected to rise to 60,000 BOPD.
IMPORTANT NOTICE (4):
Produced hydrocarbons from Upper Jurassic lesser carbonate (Sabatayn
+Shuqra Formations), which are sourced from Upper Jurassic organic-rich units
(Madbi Formation) and mainly sealed by Evaporates + Carbonate rocks (Sabatayn
+Shuqra Formations). Horst type Traps: Jurassic.
2.2.4 Ayad Block 4:
(135 million barrels) in central Yemen, operated by Nimir Petroleum Company.
Production is reaching 1,500 BOPD.
IMPORTANT NOTICE (5):
(See the above-mentioned Important Notice No.4).
To these main hydrocarbons productive region of the Republic of Yemen may
be added the single oil discovery of Sharmah in the offshore area east of Mukalla.
That’s area remains undeveloped but which houses its oil in an Eocene carbonate
reservoir sourced by Eocene shales of the Jeza ‘ Formations (Haitham and Nani, 1990;
Bott et al., 1992).

6. 1. Recommendation
It is highly recommended, that other detected basin must be more studied and
carefully, with the following main aims; to determine their boundaries, extensions and
age.
Acknowledgements
I would like to express my deep gratitude and sincere thanks to the Yemeni
Ministry of Oil and Mineral Resources, for their help and support and to the Earth
Science College of Jilin University for everything they have done for me.
Special thanks go to the editors of the JOURNAL OF GEOSCIENTIFIC
RESEARCH IN NORTHEAST ASIA for publishing this paper.
References
Beydoun, Z.R., As-Saruri, M.L., and Baraba, R.S., 1996. Sedimentary basins of the
Republic of Yemen: their structural evolution and geological characteristics. Revue de
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Haitham, F.M.S. and Nani, A.S.O., 1990. The Gulf of Aden Rift: hydrocarbon
potential of the Arabian sector. J.Petrol. Geol., 13: 211-220
Hunt Oil Company Yemen, 1992; Stratigraphic Nomenclature Chart, Marib-Jawf
basin, by Mark Sturgess, Ian Maycock and Gary Mitchell
Maycock, I.D., 1986. Oil exploration and development in Marib – Al Jawf Basin,
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Unpublished)