Open Access Original Research Article

A Numerical Hazard Rating Method for Debris Slide Susceptibility Mapping in Turkana, Kenya

I. E. Osumgborogwu, C. N. Chibo

Journal of Geography, Environment and Earth Science International, Page 1-14
DOI: 10.9734/JGEESI/2016/30548

This study presents a numerical rating method for mapping debris slide susceptibility in               Turkana, Kenya. The use of remotely sensed data; 31 m digital elevation model (DEM) 1.5 m SPOT 6 image of study area, and an exploratory soil and agro-climatic zone map of Kenya, (1:1,000,000) were adopted. Numerical hazard rating scheme for testing relationship between debris slide and five event controlling parameters; slope angle, friction angle of soil, soil drainage, soil thickness and proximity to drainage is described. Corresponding thematic data layers were generated for these parameters in ArcGIS. Numerical hazard ratings were assigned to these parameters on a scale of 0 – 5 with 0 being the least susceptible class and 5 having the greatest susceptibility to debris slide. These hazard ratings were justified with the use of the Coulomb Equation of stability analysis. Debris slide susceptibility map indicates that areas close to drainage channels had the highest susceptibility value ranging from 3 – 5. On the hand, areas with no surface material, i.e., bedrock outcrop, and low slope angles had minimal susceptibility value of zero (0). There was no landslide data for the study area and hence the debris slide susceptibility map could not be validated. This study therefore has developed a method for debris slide susceptibility assessment that can be adopted in an inaccessible terrain, or in an environment with no landslide data.

 

Open Access Original Research Article

Integrated Reservoir Characterization of “XOX” Field in the Southern Niger Delta, Nigeria

Aigbedion Isaac, Dawodu Francis

Journal of Geography, Environment and Earth Science International, Page 1-10
DOI: 10.9734/JGEESI/2016/29980

3D seismic sections, composite well logs and check-shot data were used for four wells in this study. The wells were drilled to the depths of (i) 1627-2541 m, (ii) 1726-2804 m, (iii) 1788-2994 m and (iv) 1955-3409 m. All data were loaded in the petrel software. The in-line (dip) is 1281 and cross-line (strike) 5382 covering a total area of 164,019 m2 with a line spacing of 25 m. Five hydrocarbon producing reservoirs (A1, A2, A3, A4, and A5) were identified. Well-to-seismic tie revealed that hydrocarbon bearing reservoirs were associated with direct hydrocarbon indicator. Five horizons were studied and four faults mapped for the purpose of carrying out 3-D subsurface structural interpretation. The study showed that the ‘XOX’-field bears a considerable amount of 129,931,627.6 million square cubic feet (MMSCF) of gas in-place and about 173,579,727.3 million barrels (MMBSTB) of oil reserve which could be exploited for commercial purpose.

 

Open Access Original Research Article

Simple Model for the Antropogenically Forced CO2 Cycle Tested on Measured Quantities

Horst- Joachim Lüdecke, Carl Otto Weiss

Journal of Geography, Environment and Earth Science International, Page 1-12
DOI: 10.9734/JGEESI/2016/30532

The carbon dioxide information analysis center ( CDIAC ) provides a remarkable 163 years of data on atmospheric CO2 concentrations, man-made CO2 emissions, and from 1959 onwards CO2 net-fluxes into oceans and biosphere. Currently, half of the anthropogenic CO2 emissions remain in the atmosphere. Predominantly the ocean and the biosphere absorb the second half in about equal parts. We describe the anthropogenically forced CO2 dynamics by a linear model of only two parameters which represent physics and biological laws. Our model reproduces the CDIAC measurements perfectly, and allows thus predictions for the future. It does not deal with the equilibrium exchanges of CO2 between atmosphere, oceans and biosphere, but treats merely the net-fluxes resulting from the perturbation of the equilibrium by the anthropogenic emissions. Details as yielded by tracer measurements or ocean chemistry are not required. We applied the model for a tentative projection of the future COcycle based on prospective anthropogenic emission scenarios from the literature. As a result, the increase of atmospheric CO2 will gradually come to an end and the ocean as well as the biosphere will be the primary sinks of future CO2 emissions of mankind.

Open Access Original Research Article

Computer Processed Interpretation of Geophysical Logs of an Oil Field Niger Delta Sedimentary Basin, Onshore, Nigeria

L. I. Nwosu, G. O. Emujakporue

Journal of Geography, Environment and Earth Science International, Page 1-19
DOI: 10.9734/JGEESI/2016/31088

The computer processed log interpretation allows analysing and evaluating numerous types of logs with ease and presenting the results as functions of depth in graphical forms for visualisation. Computer processed interpretation of geophysical logs from five deep oil wells has been carried out for Niger Delta Sedimentary Basin. The composite wire line logs consisting of gamma ray, resistivity, density and neutron have been used for the study. The qualitative interpretation of the gamma ray log showed alternation of sandstone and shale lithologies which is an indication that the interval logged is within Agbada Formation of the Niger Delta. Four reservoirs were delineated and correlated across the five oil wells. The density and neutron logs were used for differentiating the hydrocarbon fluid into oil and gas. The delineated reservoirs were labelled as R1, R2, R3 and R4.  The R1 is a gas bearing reservoir while R2, R3 and R4 reservoirs are oil bearing. The results of the formation evaluation showed that porosity and water saturation of the reservoirs range from 19.0 to 22.7 percent and 0.19 to 0.286 respectively. The computed permeability ranges from 516 to 1662 milliDarcy (mD). The Net to Gross ratio for the four reservoirs ranges from 0.844 to 0.947. The computed values of the porosity, water saturation, Net to Gross ratio and permeability show that the four reservoirs have good to excellent quality.

 

Open Access Original Research Article

Potential Environmental Impact of Chemical and Microbial Characteristics of the Sewage Generated in Kakamega County, Kenya

Ibrahim O. Barasa, Donald N. Siamba

Journal of Geography, Environment and Earth Science International, Page 1-8
DOI: 10.9734/JGEESI/2016/30568

Sewage disposal poses serious environmental challenges yet it is largely full of organic compounds that store usable energy in their chemical bonds. A study was carried out on potential environmental impact of chemical and microbial characteristics of sewage generated in Kakamega County, Kenya. Samples of sewage from 75 schools were collected in July 2013 using bottles. The samples were taken to Water Resource and Management Authority (WRMA) and Bora laboratories for the analysis of microbes, organic nutrients and heavy metals. The research design was experimental. The results showed that the microbial characteristics of the sewage generated in secondary schools have a potential negative impact on the environment by causing pollution of the soils and water. However, the chemical characteristics of the sewage, notably the P2O5, TKN and pH have a potential positive impact on the environment by being beneficial to the soils. From the results, it is recommended that an alternative waste management technique of anaerobic digestion be used sustainably to generate bioenergy from sewage for contribution to future global energy demands and minimize its adverse environmental impact.