Amplitude Study For The Direct Hydrocarbon Detection In The Seismic Interpretation Of The Ofemini Prospect In The Eastern Niger Delta

A total of two wells were drilled in Ofemini field. Ofemini-2 well has resistivity, gamma ray, sonic and density logs as displayed alongside with the synthetic seismogram. The aim of the study is to interpret seismic sections for structures and possible hydrocarbon prospects. The data used for the study include seismic data, petrophysical logs and sandsfile. The log data covers the interpreted level (E8.0). The objective horizon (E8.0) shows fairly good sand development. Eleven 3-D seismic lines were used for the study. The average spacing for each shot point is 25m. The structural interpretation suggests that structural closure exists in the horizon mapped. The conformity of the amplitude anomaly supports that it is a direct hydrocarbon indicator. The amplitude study indicates high amplitudes on the structure and low amplitudes off the structure. The high amplitude is related to hydrocarbon while the low amplitude suggests brine saturants. The occurrence of strong amplitude reflection (amplitude anomaly) is as a result of low acoustic impedance of the hydrocarbon filled sand. This is indicative of gas accumulation and is evidenced by the well data Keywords: Seismic, Interpretation, Amplitude, Anomaly, Indicator.Global Journal of Geological Sciences Vol. 6 (1) 2008: pp. 75-9

Evaluation of hydrochemical characteristics and flow directions of groundwater quality in Udi Local Government Area Enugu State, Nigeria

A hydrogeological study was conducted at the Udi Local Government Area in south-eastern region of Nigeria to examine the hydrochemical constituent of groundwater and determine the quality for drinking and agricultural purposes. Results show that groundwater in the area is slightly acidic to slightly basic, soft and potable, when compared with the World Health Organisation standards for drinking water, and is suitable for agricultural purposes. The groundwater flow direction was determined to establish the implications of pollution from any water contamination. Twenty-one groundwater samples from existing boreholes were collected and analysed for various physicochemical parameters using standard field and laboratory techniques. Distribution of major ions was plotted on a Trilinear Piper diagram. Ajali Sandstone, known as major aquiferous layer in the area, outcrops predominately in sandy bed with medium to coarse-grained sediments. The aquifers are unconfined, semi-confined and with hydraulic conductivity values ranging from 9.0 x 10(-2) to 8.5 x 10(-2) m/day indicating medium transmissivity of groundwater in some areas and a flow net south to northward groundwater flow towards the coast. This explains why the aquifer does not appear to be very permeable and only provides a medium yield of good quality water in some regions of the study area