Wasn’t Somalia drilled for oil and gas and why new ventures now?
Petroleum exploration has extended over 60 years. The first exploratory well, the Sagaleh-1, was completed in 1956 and likewise Hobyo-1 was inscribed to have been finished in October 1956. As of the end of 2012, a total of 63 wells have been drilled. None of these wells has been commercially successful, although some have had hydrocarbon shows. The fundamental questions of finding oil in Somalia are all positive:
1. |
Has oil been generated in the area? Yes. |
· There are some large oil seeps in North Somalia (Somaliland) and in the Southwest where Ethiopia, Kenya and Somalia meet.
· In Sagaleh-1 of Agip (Puntland), oil staining was found in a porous limestone-dolomitic series of the Jurassic.
· Gira-1 of Sinclair (near Wisil in Galmudug) found a small oil show in the Jurassic
· In Cotton-1 of Agip, a good gas show was found at 91m of Cretaceous limestone.
· Auradu Paleocene limestones showed oil stains in the Sagaleh, Cotton and Gira wells.
· In Merca-1 shelf-limestones of Oligocene age of 792m showed no hydrocarbon traces but the Eocene sandstones in this well not only had good oil staining but contained gas under good pressure
· Afgoye-1 of Sinclair, north of Merca also had a good gas show.
· In Calub and Halala (Wardheer, Ethiopia), Tenneco Oil Corp discovered gas and these fields are not far from Galinsoor in Galmudug.
· Again Tenneco discovered a non-commercial oil in El Kuran near the Bakool border with Ethiopia. |
2. |
Are there suitable reservoir rocks? Yes. |
- A reservoir rock has porosity and permeability. Porous sandstone and fractured limestone are good reservoir rocks. Porous dolomitic- limestone are plenty in the sedimentary sequence of Somalia. There also basal clastics that terminated in early Jurassic. |
3. |
Are there seals or cap rocks? Yes. |
- Oil and gas accumulate only where seals occur above and around reservoir rocks so as to stop the upward migration of oil and gas and form traps. |
4. |
Are there suitable structures? Yes. |
- Structural traps: These traps hold oil and gas because the earth has been bent or deformed. The trap may be simple. Also, there are stratigraphic traps |
The Reasons why previous exploration did not reach a commercial discovery?
1. Early geologic models were incorrect – bad well location occurred in many wells.
2. Early data were of insufficient resolution – bad well location was a major problem. Many of the previous tests were drilled on old or inadequate seismic data. Better geophysical techniques and modern explorations concepts will provide improved opportunities for any exploration undertaken in the future.
3. Technological development in seismic surveying and in other areas of exploration has occurred and now exploration is more promising.
4. Favourable terms and a new petroleum law with a production sharing agreement, were passed by the parliament in 2006 and Somalia is ready for exploration, development, production and exporting.
5. Stability is slowly coming back and the country is democratically transforming.
6. Location and geographical: Not far away from the emerging markets of China and India and the production is easily exportable.
Why is Somalia under-explored and neglected for so long?
Somalia has been sparsely explored. The drilling density shows you that wells are spaced far away from each other. However, Somalia contains several exploration plays with world-class potential that remain to be tested. Just prior to the collapse of the “Somali State” in December of 1990, several concessions were held by major international petroleum companies and at least three key wells were scheduled to be drilled. Then the civil war broke out and companies have to flee.
1. Political reason and instability: Petroleum exploration began after the Second World War and the first exploratory well, the Sagaleh-1 was completed in 1956. From the early seventies to mid- eighties Somalia was roughly in the Soviet Block and slight exploration occurred. Things changed after 1985 when giant oil companies rushed to Somalia to take up concessions for exploration. However, in January 1991 the Somali government collapsed and the country went into a civil war. Then the oil companies declared force majeure to return back when the political condition stabilises. Then in 2006, the then President of Somalia, Abdullahi Yussuf, invited the companies with the lease to come back to resume their work. But none came back and the force majeure condition was revoked.
2. The boom elsewhere: There was a boom going in the Middle East and then West Africa and Somalia was considered as a frontier province that requires a lot of resources. Oil companies were very busy in West Africa, the Middle East and South America, mainly Brazil.
3. Low well-density or drilling density: To this day, there are 63 wells drilled in the various basins of Somalia and none of these wells has been commercially successful although some have had shown hydrocarbon shows. One of the reasons is that wells are spaced far from each other at distances of 50 – 100 km apart and in some cases spacing was 250 – 400 km.
Oil and Gas Potential:
Most of Somalia has a Jurassic to Miocene sedimentary section that ranges from two to five km thick and is divided into seven unconformity-or transgression-bounded sequences. Thicknesses of these sequences vary significantly within eight depositional basins. There are at least eight petroleum basins in Somalia that hold potential prospects ready for exploration and development. Some of these sedimentary basins have sediment thicknesses more than five kilometres and contain good source rocks, reservoir rocks, seals and traps necessary for oil and gas to deposit.
Inland, the Jurassic to Tertiary section consists primarily of inter-bedded platform limestones and shales, locally with evaporites. This section is transitional eastward to deeper water shelf and basinal deposits along the coastal margin. Mesozoic rifts are present in northern Somalia. The early Cretaceous was a time of widespread emergence. Deltas related to major drainages developed in the Late Cretaceous and Tertiary; subsidence led to accumulation of a thick Tertiary section of deltaic and marginal marine deposits in southeastern Somalia.
The main structural elements resulted from rifting of Gondwanaland during Carboniferous to Jurassic, separation of Madagascar-India in early Late Jurassic, and opening of the Gulf of Aden in mid-Tertiary. In central and southern Somalia, warping and down-to-the-coast faulting is Late Cretaceous to mid-Tertiary in age. In the north, most deformation is related to Gulf of Aden rifting in which Africa separated from the Arabian Peninsula.
Mature, oil-prone source beds combined with potential reservoir rocks and structures occur in a variety of geological settings. Viable exploration plays include rift basins, regional arches, carbonate platform margins, deltaic complexes, and faulted basin margins.
Conclusion:
Time has come for investors and international oil companies to aggressively consider exploring for oil and gas in Somalia. The country has a lot to offer: eight sedimentary basins with columns of 5 to 6 km in several areas and a range in age from Jurassic or Triassic to Tertiary. Tectonics for the past 200 my have been extensional, leading to these thick and varied columns. Facies changes, faults, arches, and folds associated with extensional tectonics provide many possible combinations of trap, reservoir, seal and source rock.
Many of the previous tests were drilled on old or inadequate seismic data. Better geophysical techniques and modern exploration concepts will provide improved opportunities to present ventures. The country is also located geographically in a strategic place in Africa having a long coastal line and it is easy to export to India, Japan and China and other emerging markets around the world.
We remain optimistic about Somalia’s hydrocarbon potential whether it is onshore or offshore. But companies need to be socially responsible: transparent, free of corruption and bribery. We want companies to operate safely without causing environmental degradation like in Niger Delta or in the Gulf of Mexico. Likewise companies should contribute to the communities in which they operate by creating jobs, using local supplies and supporting community development. The aim is to make an ever-lasing difference to the quality of the communities’lives.
References:
1. Barnes, S.U. ; 1976, Geology and oil prospects of Somalia, East Africa; AAPG; Bulletin; v.60; pp. 389 – 413.
2. Brady Michael J and Harms, J.C; Exploration history and hydrocarbon potential of Somalia: A technical talk; Kansas Geological Society – Technical Talk 2002.
3. Bosollini, Alfonso; 1989; The continental margins of Somalia – Their structural evolution and sequence stratigraphy; Memorie Scienze Geologiche; v. 41; pp: 373 – 458.
4. Cella, F.; Dorre, A.S and Rapolla A., 1995; Gravity study of the crustal structures of Somalia along the International Lithosphere Program Geo-transects; Journal of African Earth Sceinces; Vol. 30; pp. 263 – 274.
5. Harms, J.C and Naleye, Ali M; Petroleum exploration in Somalia; Geology and mineral resources of Somalia and the surrounding regions; First Agron; Oltremare, Firenze; Relaz e Monogr. 113, pp. 417 – 428, 1993.
6. SOEC (Somaliland Oil Exploration Company), 1954; A geological reconnaissance of the sedimentary deposits of the Protectorate of the British Somaliland: London, Crown Agents for the Colonies; p.42.
Eng. Abdulkadir Abiikar, London, UK
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