Oil and Gas Exploration History in Kenya
Petroleum Exploration in Kenya began in the 1950s within the Lamu Basin. It was until 2012 when the first commercially viable oil discovery was made in the Tertiary rift, followed by significant gas discoveries in offshore Lamu basin. To date, over 86 wells have been drilled with a majority within the Tertiary Rift. An estimate of over 4 billion barrels of crude oil reserves have been encountered in the Lokichar sub-basin by Tullow Plc and its partners, with recovery oil estimated to be 750 million barrels.
National Oil through its National Data Centre (NDC) project, has an inventory of all petroleum exploration data i.e. seismic data, well logs, well reports, other oil exploration related reports, aeromagnetic and gravity data, obtained in the country by different operators in both digital and analogue formats. In addition, the corporation has set up cores and drill-cuttings storage facility which holds samples retrieved during drilling from 1960 to date.
National Oil is currently setting up a Seismic Processing center and a Geochemical-Petrophysical analysis laboratory within the new premises in Kawi House, South C.
Exploration history in the Kenyan Sedimentary basins
LAMU BASIN
British Petroleum (BP) and Shell began exploring hydrocarbons in 1954 in the Lamu Embayment which resulted in the drilling of ten wells between 1960-1971. The consortium acquired 11,982 km of 2D seismics, 29,725 km of aeromagnetic data as well as 3,814 km of gravity. None of the wells drilled were fully evaluated or completed for production despite several indications of oil staining and untested zones with gas shows in some wells.
Texas Pacific drilled Hargaso-1 in 1975 that encountered oil and gas shows. Between 1985 and 1996, Amoco and Total drilled another ten exploration wells with no significant success though minor oil and gas shows were encountered in some of the wells.
Interest in the offshore Lamu Basin within the 1970s-1980s resulted in the drilling of three wells; Simba-1, Maridadi-1 and Kofia-1. Simba-1 was unsuccessful while the latter two encountered hydrocarbon shows. A Lamu basin study by National Oil between 1991-1995 led Kenya to subdivide the basin (both onshore and offshore) into 10 exploration blocks, with a further two created by 2001. This, followed by massive gas discoveries in Mozambique in 2003, renewed exploration interest within the region. Gazettement of new blocks in 2003 allowed Woodside Petroleum to farm into seven offshore blocks, acquiring 11,449.6 km of 2D seismic and drill Pomboo-1 well (dry) in 2007. To date, a further four wells have been drilled; Mbawa-1 (gas discovery), Kubwa-1 (dry), Kiboko-1 (dry) and Sunbird-1 (oil and gas discovery). So far, additional 2D and 3D seismic have been acquired within the region as well as additional blocks created from relinquished acreage both onshore and offshore.
TERTIARY RIFT BASIN
Before the 1980s, the tertiary rift was considered inferior exploration-wise with little activity. Shell drilled Eliye Springs-1 (dry) in 1992 and Loperot-1 (oil shows) in 1993 within the Lokichar sub-basin. This was followed by a period of exploration hiatus that lasted to 2006 when oil was discovered in the Albertine graben in Uganda. Tullow Oil Plc and Africa Oil acquired additional 2D seismic in the region and in 2012 drilled Ngamia-1 well, the first oil discovery in the basin encountering over 100m net oil pay zones. A series of 2D and 3D seismic acquisition programs have been carried out to date with over 40 exploration and appraisal wells drilled opening up the Lokichar sub-basin. Currently, joint field development studies between Tullow Oil, the Ministry of Petroleum and Mining (Petroleum Directorate) and National Oil Corporation of Kenya are ongoing to give Kenya its best development options.
National Oil operates its own exploration acreage in Block 14T which is located within the southern Tertiary Rift Basin where gravity (FTG), magnetotellurics (MT), aeromagnetic and seismic data have been acquired. Additional acquisition of 2D seismic was carried out in 2017 with two stratigraphic wells drilled by the early 2018.
MANDERA BASIN
Between the 1960s-70s, Frobisher Ltd and Burmah Oil conducted photo geological field geology, gravity, aeromagnetic and seismic surveys that did not materialize into drilling programs. Elgal 1 & 2 (1987) and were drilled by Amoco but were both dry. In 1990, Total E&P Company acquired 707 km of 2D seismics within this region. Between 2008 and 2013, EAX and Lion Petroleum acquired additional 2D seismic in the region, with Lion Petroleum drilling Badada-1 well (dry) in 2015.
ANZA BASIN
Acquisition of seismic data within the Anza Basin commenced in 1975 when Whitestone acquired 2D seismic data, with further acquisition surveys carried out by the Ministry of Energy, Chevron, Total E&P, Amoco & Shell over time. On acquiring seismics, Chevron later drilled Anza-1 and Bahati-1 (both dry), Total E&P drilled Ndovu-1 (oil and gas shows), Duma-1 (gas shows) and Kaisut-1 (dry) while Amoco drilled Sirius-1, Bellatrix-1, Chalbi-3, Hothori-1 (all three-had oil and gas shows) and Endela-1 (gas shows).
Additional 2D and 3D seismic have been acquired by Vanoil, Lion Petroleum, CNOOC, Africa Oil and Tullow in this basin from 2007 to date. The first hydrocarbon discovery was made in 2009 by CNOOC in Bogal-1 well, that encountered gas with a gross best estimate of 2500 Bcf. Tullow later drilled Paipai-1 well that encountered light hydrocarbon shows. Another gas discovery was made in the Sala-1 well in 2014 by Africa Oil within three distinct zones of interest over a 1000-meter gross interval. However, the subsequent Sala-2 well drilled to test the updip extent of this main reservoir sand in the Sala-1 gas discovery failed to find any significant hydrocarbons.