The Scent of Oil amongst Gas
In the last decade several large Gas discoveries have been in East Africa, with up to 200 tcf of gas, equivalent to more than 30 Bbbl of oil reserves, have been discovered in Mozambique and Tanzania in recent years.
These huge discoveries are currently being queued up for development and are seeking an export market.
It is then with great excitement that Spectrum’s new seismic data, collected between 2014-2016 offshore Somalia, has revealed what has been previously missing from the East African margin – the scent of oil.
As Somalia announces plans to open its first offshore exploration license round, (orange, left) explorers analysing new seismic data have recognized the potential of finding reserves to match those of its neighbours in East Africa.
Beyond that, critically, they are discovering that Somalia’s potential is not just gas: Here lies a gem of an unexplored oil basin.
Round Timeline Set in place
A date of 7 February 2019 has been set for an auspicious launch event in London at Claridges Hotel when the Ministry of Petroleum and Mineral Resources will unveil the final block delineation, expected to consist of up to 50 blocks covering a total area of over 173,000 km^2. During this launch they also plan to reveal the legal & regulatory framework, petroleum laws, local capacity, fiscal terms, round timings and other conditions. This event is also expected to include geological presentations gained through insight provided by Spectrum’s 2D seismic data across the open blocks. The round is set to close on 11 July 2019.
The Oil Source Question
This 2D seismic data is being interrogated by geoscientists to demonstrate the presence of the three critical factors for oil to be trapped underground. There must be a source rock – shale containing organic material that is buried at the right temperature and pressure conditions for generation. The oil that is formed must then flow through pores and fractures to a reservoir where it collects, displacing water between grains of sand, and then this oil must be trapped – where it is held underground by impermeable strata. Analysis of the new seismic data offshore Somalia has allowed the critical factors of this puzzle to be identified.
In Somalia, indeed, in any unexplored basin, an explorer’s first question is whether there is a source rock that has been buried deep enough to be mature. If the source rock is too cold (i.e. buried insufficiently) then no oil forms. If the source rock is too hot (i.e. buried too deep) then the oil is cracked or broken down to methane gas. Yet like good-tasting porridge, if the temperature is just right, the source rock will produce oil product in what is called the Goldilocks Zone.
Basin Structure
Broadly, the geology of the Somalian margin can be divided into a northern zone (the Obbia and Coriole basins) underlain by highly stretched continental crust (sands, shales, limestones, and old metamorphic rocks), and a southern zone (Juba-Lamu basin) underlain by oceanic crust (volcanics). In the northern area, the temperature in the earth increases rapidly with depth such that the main source rocks (Jurassic) lying a modest 2-3 km (1.2-1.8 mi) below the seabed, are mature for generating oil rather than gas today. In the south, the underlying colder oceanic crust lets the temperature rise only slowly with depth such that the main source rocks that are more deeply buried (3-4 km/1.8-2.4 mi) in this region are serendipitously still generating oil today. Oil as the primary hydrocarbon phase offshore Somalia is supported by observation on satellite data of clusters of repeating natural oil slicks on the ocean surface.
Conclusions
The announcement of the country’s upcoming license round is perfectly timed to coincide with the availability of new seismic data. This excites international geoscientists by demonstrating a clear oil-prone series of prospects offshore the whole length of the Somalian margin. In the north, large tilted fault blocks, reefal buildups, and huge anticlinal folds of rock are seen to lie next to oil generative source kitchens. In the south, huge structures similar to those seen in the super giant Rovuma basin (Mozambique) discoveries have been observed sitting over oil-prone rather than gas-prone kitchens. Additionally, large, well-defined fold belts are found in the near-shore section offering targets that are cheap to drill with very attractive potential.
The first drilling in this exciting basin is expected to occur as early as 2018, and should open the door to this new oil province bringing much needed benefit to Somalia and a new economic stability to the region. Somalia exploration has been dormant for a generation. In those 25 years of sleep, the international exploration industry has transformed the technology available for seismic acquisition, processing, interpretation, and drilling.
Now Somalian exploration awakens to a new world with incredible new technologies and the capability to reduce exploration risk and ensure early success. It awakens not only to a stable government with capability and intent to rapidly develop Somalian natural resources, but also to the recognition that this is the part of East Africa where hydrocarbon wealth will not just be defined by the development of long-term gas projects, but from the discovery of earth’s richest natural resource prize – oil.
Click the links to see the full report and a detailed map.
- Created by
Phil Hargreaves and Robert Macdonald- Supported by
The Somalian Ministry of Petroleum and Mineral Resources
http://spectrumgeo.maps.arcgis.com/apps/Cascade/index.html?appid=c25e07e456f0414abcb54abfc1f896b0
http://www.arcgis.com/apps/webappvi...,-408877.5424,6214667.8259,827567.8271,102100