So you’ve been hearing about BLOCK 10BB, BLOCK 10A, BLOCK L-10B, but how were these blocks named?

Take a look at the map below and keep it in mind it will be the focus of this post.

Initially Kenya had seven oil blocks, segmented originally from the county of Mandera on the Somali – Kenya border. Block one was in Mandera extending north to south from Mandera to Lamu. You can see remnants of the initial blocks one to three in the map above. Before I explain where the rest of the Blocks went to let me explain where the letters came from.

According to the PSC, contractors have a 3-2-2 program with the government. The first 3 years is for Geology & Geophysical Survey (GNG), followed by detailed study and production. After the Initial 3 years, acreage that isn’t in use is to be surrendered back to the govt which forms a new block to be given to another contractor. After the blocks are reassigned a letter is added to the original block number for example BLOCK 2A, BLOCK 2B et cetera.

The initial Blocks four to seven were done away with and the area renamed afresh with the “L” prefix showing they are in the Lamu Basin. Lamu Basin is the biggest exploration basin in Kenya and includes both onshore and offshore blocks and covers all of the Kenyan coast extending inwards into the former Eastern and North Eastern provinces.


For the Tertiary rift the suffix “T” is given but only for blocks 14T, 13T and a new block 15T to be placed next to Blocks 13T- and Block 10BB after being divided.

As much as the Tertiary rift cuts from Turkana to Magadi, there are numerous sub basins and these sub basins have a number of prospects. So different wells are named according to the prospect target e.g Ekales, Ngamia, Bogal, Paipai etc. Then the wells are given numbers to differentiate different wells in the same prospects so Ngamia I, Twiga South I, Pate I and so on were the first wells drilled. In case they are to drill more wells in the area Ngamia II is a probable name. This is however left to the discretion of the contractors.

(Pictures courtesy of NOCK)