Learn more about Kenya’s Block 3A Oil Exploration

Resource Type: Oil, Natural Gas
Property Size: 12,192sq km
Stage of Development: Exploration
Current Work Program: EIA, data interpretation & preparation of the 2010 seismic program
Potential: Unknown
Ownership: Production Sharing Contract(PSC) signed in October, 2007


In October 2007, Vanoil signed a Production Sharing Contract for Block 3A [12,192 km2] located mainly in the Anza Graben in northeastern Kenya.

Vanoil chose Block 3A based on its technical merits following a study conducted by the company that identified several structural and stratigraphic leads.

We believe this is a highly prospective region signified by our study and the signing of lucrative production sharing contracts by major oil corporations such as the Chinese National Offshore Oil Company [CNOOC] and Africa Oil Corp [Lundin].

In April of 2007 the Chinese National Offshore Oil company,(CNOOC) Limited, whose contracts cover a total of 115,343 square kilometers, acquired production sharing contracts for two Blocks, including block 09 located in the Anza Graben, and adjacent to Vanoil’s Block 3A. Currently, CNOOC is drilling their first exploratory well in Block 09 with primary targets being Cretaceous and Jurassic reservoirs.

Exploration History

Exploration in Block 3A dates back in 70’s when Chevron acquired seismic, gravity and magnetic data and drilled to two exploratory well [one well in Block 3A]. Subsequent exploration programs during the 80’s by Amoco included acquisition of more 2D seismic and gravity data and culminated in drilling one exploratory well.

The overall results of geological, geophysical, geochemical studies and drilling in Anza Graben including Block 3A have proved the existence of excellent quality Cretaceous oil-prone source rocks, in addition to good quality sandstone reservoirs and a multitude of structural leads. These potential targets remain to be tested in Block 3A.


The Block 3A acreage is confined to the Anza and Mochesa rift basins in northeast Kenya. Faulting in Block 3A was initiated in the Mesozoic period and has intermittently been activated through to Tertiary with creation of depo-centres filled primarily with fluvial-lacustrine, deltaic and marine sediments.

The Block 3A acreage occupies a convergence area of three sedimentary basins of Anza and Mochesa with the third rift basin of Lamu Embayment occupying the adjacent Vanoil’s block 3B to the south.

The part of the Anza basin [Graben] in Block 3A constituted the rift termination zone of the Central African Rift System in north east Kenya. Anza graben forms the south-eastern extension of the prolific Melut and Muglad rift basins of Southern Sudan where a Cretaceous working petroleum system have been proved and oil discovered.

Potential source rocks for hydrocarbon generation and evidences of a Cretaceous working petroleum system exist in Anza Graben in Chalbi sub-basin to the north-east of Block 3A. Relatively thick [locally <4,000m] prospective Cretaceous sequences are present in Block 3A.

Prolific Melut and Muglad basins have equivalent Cretaceous sequences with a proven working Cretaceous petroleum system responsible for discoveries in the two rift basins.

Hydrocarbon trapping mechanisms in Block 3A include tilted fault blocks, faulted anticlinal closures and stratigrahic traps. The Anza rift termination zone in Block 3A is structurally interesting as a play zone and the detailed interpretation of the re-processed seismic data will further increase structural clarity on faulting and horizon imaging.

Current and Future Work Programs

The initial preliminary interpretation of the re-processed seismic data including the integration with gravity and magnetic data creating a basin model and delineating structural and stratigraphic leads have been completed.

Currently Vanoil is undertaking the EIA program and also planning for 2010 seismic and gravity program in Block 3A. The final EIA report has been received by Vanoil from the Earthview Geoconsultants [EIA contractor] and presented to the Kenya National Environment Management Agent [NEMA] for issuance of the EIA licenses in accordance with legislative requirements.

The 2010 seismic program will include acquisition of 324 line-km in-fill 2D seismic and approximately 1,025 gravity stations. The 2010 Seismic and gravity program will be undertaken to precisely define the prioritized leads and mature some leads to prospects and to drillable targets.

Within the initial exploration period of three contract years and nine months, Vanoil will also drill one exploratory well to test generation and entrapment of hydrocarbons in Block 3A.

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