| Abstract |
The concept of wellhead generators is to realize early generation and supply of electricity for various purposes. At Olkaria, units of 5MW have been installed at well OW-37, 12.8MW at OW-43, 27.8MW at OW-914, 10MW at OW-915 and 2MW at Eburru. All are operational and there are plans to install more units of 10MW at OW-37, 5MW at OW-39, 5MW at OW-905 and another 5MW at OW-919. The process of drilling geothermal wells uses diesel fuel as a means of generating the required power for the several equipment in the rig. Diesel is used by generators to produce the required electric power for both the DC and AC equipment on the rig. Diesel is also used by the air compressor machines used during aerated drilling process. The total diesel used at the KenGen new rigs during drilling is estimated at 70% by the electric generators and 30% by the aerated system. The generating sets supply power to the SCR module which powers the mud pumps, draw works and the rotary table DC motors. It also supplies AC power to the top drive system, the drilling fluid circulation system and the rig lighting system. The aerated system in each rig comprise of five (5) primary compressors and two (2) booster compressors which are purely diesel engine driven. The average diesel consumption per rig per 24-hour drilling operation is 4000 litres. Part of the electrical power from wellhead units can therefore be used at the rigs to substitute electrical power from the generators and hence save 70% of the total fuel consumed by the rigs. This is possible when drilling on the same pad as the wellhead units or when the rig is drilling on a pad near a wellhead generator. The remaining 30% of the fuel will continue to be used by the rig aerated system since the equipment are engine driven. This paper will analyse and demonstrate the benefits and savings that will be realized by using wellhead power to drill geothermal wells. These include reduced carbon emissions, noise levels, fuel spillages at the rigs and importantly improved profits for the Company. |