Discussion on the Method of Land Quality Geochemical Evaluation Database : A Case Study of Diao Town and Xinzhai Town of Zhangqiu City

The land quality geochemical evaluation database was mainly based on soil geochemical surveys.During its construction process,geochemical survey data involving atmospheric dry(wet)sediments,irrigation water,fertilizers and crops was simultaneously collected,analyzed and compiled into result maps using MAPGIS.ACCESS was used to manage standardized result data to establish an evaluation database.The database included a basic spatial database involving regional geography,topography,soil type and land use,a spatial evaluation database centered on the sampling layout of the work areas of soil,irrigation water,crops and other media,the distribution and changes of soil chemical elements,the classification of soil pollution and the classification of soil element environment and nutrients,and an evaluation database of various result maps such as land planning map,characteristic agricultural product planting plan suggestion map and fertilization suggestion map.The database realized the scientific and effective management of the samples and corresponding numerous laboratory analysis data,and provides basic information for the geochemical survey and evaluation of the land quality in the evaluation areas and the overall comprehensive research,and an important basis for promoting the adjustment of agricultural economic planning,the development of modern green agriculture and the development and utilization of high-quality characteristic land resources.

Geochemical Evaluation for the Hydrocarbon Potential of Source Rocks in the Anza Basin

Anza basin is located in the extensional arm of the central African rift system in the North-Eastern part of Kenya. Cretaceous sedimentary rocks were sampled from the four wells namely, Chalbi-3, Sirius-1, Ndovu-1 and Kaisut-1. Anza basin occurs on a fault block within a Paleocene-Cretaceous rift basin. The methodological approach used for the evaluation of source rocks included petrophysical and geochemical methods to ascertain their potential. Well sections with a higher shale-volume ratio were sampled for geochemical screening to determine the organic richness and thermal maturity of potential source rocks, respectively. Source rock with organic richness ≥ 0.5% were evaluated further for their petroleum potential using Rock-Eval pyrolysis to determine their thermal maturity, organo-facies and in-situ generated hydrocarbons present in sedimentary facies. The geochemical evaluation of rock samples from the drilled wells’ sections of Chalbi-3 and Sirius-1 confirmed both oil and gas potential. Gas Chromatography and Mass Spectrometry (GCMS) were used to characterize the biomarker signatures and oil-oil correlation of Sirius-1 samples. A predictive model was developed to integrate the petrophysical and geochemical data to reveal hydrocarbons’ potential in the Anza basin.