Geo-Electric Investigation of Flammable Natural Gas in Kipeto Area, Kajiado County in Kenya

Abstract

Vertical Electrical Sounding (VES) survey using Schlumberger electrode configuration was employed in Kipeto area, Kajiado County with an objective to determine the extent of natural flammable natural gas and to characterize its subsurface geo-electrical structures. Apparent resistivity was measured using a Geotron G41 terrameter. A Global Positioning System (GPS) was used to position each station in the field. A total of eight VES stations were conducted around the Gas point (BH1) with a maximum current electrode separation of 500 m. The data was qualitatively analysed with the help of computer software; IP2Win.The study provided preliminary findings of a possible displacement of water aquifer by a flammable gas in small signatures, which might be an extension of an extensive gas zone. In addition it was noted that this is enhanced by the fractured subsurface. The VES results revealed that the area has 2 to 5 geo-electric layers: Dump black cotton soil with resistivity average and thickness of 66.67 Ωm and 4.41 m; slightly weathered layer with 180.95 Ωm and 7.16 m; Fresh volcanic layer with 245.56 and 23.76 m; highly weathered volcanics with clay 11.6 Ωm and 5 m and Fresh weathered volcanics with 1146 Ωm and infinity thickness. At a depth from 200 m for VES 1,4,6 and 8, is an extensive layer of low resistivity about 6 Ωm-13 Ωm. This layer might be moist and muddy.