Geospatial Predictive Model for Estimating Soil Thermal Conductivity and Diffusivity of Owaza Gas Flaring Site , Southeastern Nigeria

In this study, predictive model for estimating the soil thermal conductivity and diffusivity from fourteen different sample points around a horizontal gas flaring site was employed in two depths (0 – 15 cm and 15 – 30 cm). Seven of these points were within the gas flare bond wall. In contrast, other points were located outside the bond wall at varying distances in the direction of the flaring. Soil temperature was determined in situ using a mercury-in-glass thermometer from these points. Core-samplers were driven into these points for dry bulk density and moisture determination. Simple descriptive statistics of mean, standard deviation and detailed geostatistics were employed to describe the variability and spatial distribution patterns of the soil thermal properties using ArcGIS 10.1. Results showed soil temperature increasing significantly (23.5 – 45 oC) as distance decreased towards the flare point. The predicted soil thermal conductivity and diffusivity values varied from 1.65 - 4.89 Wm-1K-1 and 0.77- 2.05 m2s-1 within the flare bond wall and 1.58 – 1.72 Wm-1K-1 and 0.56 – 0.71 m2s-1 outside the wall at 0 – 15 cm and 15 - 30 cm depths respectively. The spatial distribution maps for both soil depths showed significant variations. From the predictive soil thermal conductivity and diffusivity values, arable soil within the flare site is not suitable for agricultural activities. Therefore, for good soil health and physical characteristics, a distance of 4 km away from the flare site is recommended as soil temperature decreases with increasing distance from the site.