The study assessed petroleum systems in the southern Bida Basin,Nigeria,focusing on the Cretaceous sediments.Reservoirs comprise Lokoja and Patti Formation sandstones,while shales,claystone,and siltstone serve as sour...The study assessed petroleum systems in the southern Bida Basin,Nigeria,focusing on the Cretaceous sediments.Reservoirs comprise Lokoja and Patti Formation sandstones,while shales,claystone,and siltstone serve as source rocks and stratigraphic traps/seals.Detailed studies delineating the key elements of the petroleum systems in the basin have not been conducted due to a lack of subsurface data.The goal of the current study was to use field observations,Scanning Electron Microscopy(SEM),X-ray diffraction(XRD),and geochemical and geomechanical data to evaluate key components of petroleum systems in the southern Bida Basin.The results presented in this investigation are intended to attain specific objectives,especially those lacking in the basin's study sections.Petrophysical analysis revealed that the Lokoja Sandstone has porosity of 37%-39.5%and moderate permeability of 23.22-42.29 mD.The Patti Formation sandstone reservoirs exhibited high porosity(38%-42%)and moderate to good permeability(31.54-66.48 mD),suggesting good potential reservoirs.SEM results revealed intragranular pores and micro-fractures in the Patti Shale,whereas the sandstone reservoirs in the Lokoja and Patti formations displayed fractures,facilitating hydrocarbon migration.Quartz was the dominant mineral in the sandstone units of both formations.XRD analysis revealed that brittle and clay minerals influenced the microstructure of Patti Shale.Geochemical analysis indicated promising petroleum potential in the Patti Shale,with a total organic carbon(TOC)content of 1.87 wt%,free hydrocarbon from kerogen(S1)of 0.41 mg/g,hydrogen index(HI)of 0.75 mg HC/g TOC,and production index(PI)of 0.17.The Patti and Lokoja formations'shale,claystone,and siltstone exhibited sealing potential,with a plasticity index of 24-35 and coefficient permeability of 2.8×10^(-4)-3.6×10^(-4)cm/s.Field studies,XRD,geochemical data,and geomechanical index values have confirmed the key components of the petroleum system,which in turn facilitate hydrocarbon generation,migration,accumulation,and entrapment in the basin.展开更多
Leaf area index(LAI)is one of the most important characteristics of forest stands that affects the fundamentals of tree physiological processes,biomass production,and mechanical stability.The LAI results obtained by t...Leaf area index(LAI)is one of the most important characteristics of forest stands that affects the fundamentals of tree physiological processes,biomass production,and mechanical stability.The LAI results obtained by the semi-direct and indirect methods(the needle technique and an LAI-2000 PCA)in three European beech(Fagus sylvatica L.)stands and one sycamore maple(Acer pseudoplatanus L.)stand were compared with LAI estimated by litter traps during the 2013 growing season.Seasonal LAI was estimated using an LAI-2000 PCA which showed similar trends among the stands and strongly corresponded to phenological phases of deciduous stands in Europe,with the fastest rate of leaf area increment occurring during the first month following bud break.During the growing season,maximum stand LAI value was on June 19th and reached 4.5–5.1,and 4.0 in the beech and maple stands,respectively.The needle technique significantly underestimated(p<0.05)direct LAI on average by 22.0% and 40.0% in the beech and maple stands,respectively.The LAI-2000 PCA insignificantly underestimated(p>05)LAI on average by 15.1%and 5.8%in the beech and maple stands,respectively.All methods for LAI estimation at the stand level could be applicable in deciduous forest stands(beech,maple)with similar site and stand characteristics.However,calibration by direct method is necessary to obtain the required precision.展开更多
文摘The study assessed petroleum systems in the southern Bida Basin,Nigeria,focusing on the Cretaceous sediments.Reservoirs comprise Lokoja and Patti Formation sandstones,while shales,claystone,and siltstone serve as source rocks and stratigraphic traps/seals.Detailed studies delineating the key elements of the petroleum systems in the basin have not been conducted due to a lack of subsurface data.The goal of the current study was to use field observations,Scanning Electron Microscopy(SEM),X-ray diffraction(XRD),and geochemical and geomechanical data to evaluate key components of petroleum systems in the southern Bida Basin.The results presented in this investigation are intended to attain specific objectives,especially those lacking in the basin's study sections.Petrophysical analysis revealed that the Lokoja Sandstone has porosity of 37%-39.5%and moderate permeability of 23.22-42.29 mD.The Patti Formation sandstone reservoirs exhibited high porosity(38%-42%)and moderate to good permeability(31.54-66.48 mD),suggesting good potential reservoirs.SEM results revealed intragranular pores and micro-fractures in the Patti Shale,whereas the sandstone reservoirs in the Lokoja and Patti formations displayed fractures,facilitating hydrocarbon migration.Quartz was the dominant mineral in the sandstone units of both formations.XRD analysis revealed that brittle and clay minerals influenced the microstructure of Patti Shale.Geochemical analysis indicated promising petroleum potential in the Patti Shale,with a total organic carbon(TOC)content of 1.87 wt%,free hydrocarbon from kerogen(S1)of 0.41 mg/g,hydrogen index(HI)of 0.75 mg HC/g TOC,and production index(PI)of 0.17.The Patti and Lokoja formations'shale,claystone,and siltstone exhibited sealing potential,with a plasticity index of 24-35 and coefficient permeability of 2.8×10^(-4)-3.6×10^(-4)cm/s.Field studies,XRD,geochemical data,and geomechanical index values have confirmed the key components of the petroleum system,which in turn facilitate hydrocarbon generation,migration,accumulation,and entrapment in the basin.
基金supported by the Specific University Research Fund of the Faculty of Forestry and Wood Technology(FFWT)at Mendel University in Brno(Grant No.LDF_VP_2016017)the Ministry of Agriculture of the Czech Republic,institutional support MZE-RO0118。
文摘Leaf area index(LAI)is one of the most important characteristics of forest stands that affects the fundamentals of tree physiological processes,biomass production,and mechanical stability.The LAI results obtained by the semi-direct and indirect methods(the needle technique and an LAI-2000 PCA)in three European beech(Fagus sylvatica L.)stands and one sycamore maple(Acer pseudoplatanus L.)stand were compared with LAI estimated by litter traps during the 2013 growing season.Seasonal LAI was estimated using an LAI-2000 PCA which showed similar trends among the stands and strongly corresponded to phenological phases of deciduous stands in Europe,with the fastest rate of leaf area increment occurring during the first month following bud break.During the growing season,maximum stand LAI value was on June 19th and reached 4.5–5.1,and 4.0 in the beech and maple stands,respectively.The needle technique significantly underestimated(p<0.05)direct LAI on average by 22.0% and 40.0% in the beech and maple stands,respectively.The LAI-2000 PCA insignificantly underestimated(p>05)LAI on average by 15.1%and 5.8%in the beech and maple stands,respectively.All methods for LAI estimation at the stand level could be applicable in deciduous forest stands(beech,maple)with similar site and stand characteristics.However,calibration by direct method is necessary to obtain the required precision.
