Radiogenic Heat Production from Well Logs in Part of Niger Delta Sedimentary Basin, Nigeria.

Abstract

The radiogenic heat produced from radioactive elements has been investigated in some parts of Niger Delta sedimentary basin. The heat production was computed from gamma ray logs for three oil producing wells. The major lithology observed in the gamma ray log is alternation of sand and shale. The computed value ranges between0.35 to 2.0μWm-3 for well 1, 0.34 to 1.78μWm-3 for well 2 and 0.24 to 2.0μWm-3 for well 3. The average radiogenic heat production ranges between 0.3 to 1.93μWm-3. It was observed that the heat production within the sand lithology ranges from 0.24 to 0.7μWm-3.Whilethe computed value for the shale lithology ranges from 0.8 to 2.0 μWm-3. The high radiogenic heat production in shale was as a result of high concentration of radioactive elements. The sandstone zone was deficient of radioactive elements and this resulted in the low value. The plot of depth against radiogenic heat production was scattered and it also showed an increase with depth. The increase was due to high shale lithology at greater depth of the Agbada Formation and the shale in the Akata Formation. A linear relationship was established for the radiogenic heat production and the product of gamma ray and density logs for the study Area. The relationship can be used if gamma ray spectral logs are not available.