The Kowe Block, approximately 20 km offshore Gabon with a water depth of 100m, contains three fields, Tchatamba Marin, Tchatamba South and Tchatamba West, together the `Tchatamba Complex`. Discovered between 1993-1997, production from the fields started in 1998. A peak production of 43 Kbopd was reached in 2001.
Production proved to be stronger than originally planned and with additional reserves proven, the facilities were extended in 2003 and a permanent pipeline was constructed directly to the onshore Cap Lopez terminal.
Production in all three fields is from the Lower Cretaceous Madiela, Cap Lopez, Azile and Anguille reservoirs, consisting of high permeable quartz and carbonate shallow marine sands.
Due to the excellent reservoir quality and aquifer strength, no water injection is required. Pressure support is through natural water drive and produced water is treated before disposal. High quality sweet crude (40 API) from the Madiela and Cap Lopez reservoirs is mixed with the slightly sour hydrocarbons from the Azile and Anguille reservoirs. For lifting and export, all crude is currently blended as part of Oguendjo blend.
In late 2009, Perenco took over the operation from Marathon. Perenco, present in Gabon since 1992, has been actively expanding its business in recent years and has been able to improve the overall uptime of the facilities. In 2014 a drilling campaign was started. Since then five new wells have been drilled on Tchatamba Marin and two new ones on Tchatamba South. Three of those were drilled horizontally, which led to high initial rates of up to 6,000 bopd per well.
By development drilling, the addition of new perforations in existing wells and production optimization, it has proven possible to maintain overall field production at a level of 20 Kbopd even today.
In Q4 2014 a new export line to the Fernan Vaz FPSO was operational, making the Tchatamba crude part of the Oguendjo Blend. To counter limitations in H2S treatment, water handling and power generation, and to allow further development drilling, a second MOPU is currently being installed on Tchatamba Marin. It will be commissioned in April 2017.
Since 2016 a new lifting contract with Perenco has been established with monthly oil liftings and a net production of almost 4,000 bopd. This brings ONE a steady source of revenues during the year.