Based on porosity and permeability measurements, mercury porosimetry measurements, thin section analyses, SEM observations, X-ray diffraction （XRD） analysis and granulometric analyses, diagenetic features of reservo...Based on porosity and permeability measurements, mercury porosimetry measurements, thin section analyses, SEM observations, X-ray diffraction （XRD） analysis and granulometric analyses, diagenetic features of reservoir sandstones taken from the Zhuhai formation in the Panyu low-uplift of the Pear River Mouth Basin were examined. This study shows that chlorite cements are one of the most important diagenetic features of reservoir sandstones. The precipitation of chlorite was controlled by multiple factors and its development occurred early in eo-diagenesis and continued till Stage A of middle diagenesis. The precipitation of chlorite at the early stage was mainly affected by the sedimentary environment and provenance. Abundant Fe- and Mg-rich materials were supplied during the deposition of distributary channel sediments in the deltaic front setting and mainly in alkaline conditions. With the burial depth increasing, smectite and kaolinite tended to be transformed into chlorite. Smectite cements were completely transformed into chlorite in sandstones of the studied area. Volcanic lithics rich in Fe and Mg materials were dissolved and released Fe2＋ and Mg 2＋ into the pore water. These cations precipitated as chlorite cements in middle diagenesis in an alkaline diagenetic environment. Chlorite coatings acted as porosity and permeability, thus helping preserve cements in the chlorite cemented sandstones. The reservoir quality of chlorite cemented sandstones is much better than sandstones without chlorite cements. Chlorite cements play an important role in the reservoir evolution that was mainly characterized by preserving intergranular porosity and forming better pore-throat structures of sandstones.展开更多
Ecological security of arable land is closely related to grain security and social stability. This paper took 12 typical indexes from the aspects of ecological pressure, state and response of arable land considering n...Ecological security of arable land is closely related to grain security and social stability. This paper took 12 typical indexes from the aspects of ecological pressure, state and response of arable land considering natural, social and economic conditions to construct the ecological index system of arable land in Panyu District, Guangzhou City, and adopted objective weighting method and comprehensive analysis method to analyze the dynamic change of ecological security and security level of arable land in the study area. The results showed that ecological security pressure value and response value of arable land in Panyu District from 2008 to 2013 increased and the overall ecological security level was low, manifesting the level of "sensitive–risky–sensitive". Specifi cally, ecological security of arable land in 2008 was sensitive, risky from 2009 to 2011, and the security level rose to the sensitive level again in 2012 and 2013. Ecological restoration and rebuilding of arable land should be enhanced, and ecological security early warning system should be established by protecting quantity and quality of arable land, so as to protect arable land resources effectively, and promote sustainable development of arable land.展开更多
基金supported by the China National Science & Technology Project(2008ZX05025-006)the China 973 Key Foundation Research Development Project(2009CB219400)
文摘Based on porosity and permeability measurements, mercury porosimetry measurements, thin section analyses, SEM observations, X-ray diffraction （XRD） analysis and granulometric analyses, diagenetic features of reservoir sandstones taken from the Zhuhai formation in the Panyu low-uplift of the Pear River Mouth Basin were examined. This study shows that chlorite cements are one of the most important diagenetic features of reservoir sandstones. The precipitation of chlorite was controlled by multiple factors and its development occurred early in eo-diagenesis and continued till Stage A of middle diagenesis. The precipitation of chlorite at the early stage was mainly affected by the sedimentary environment and provenance. Abundant Fe- and Mg-rich materials were supplied during the deposition of distributary channel sediments in the deltaic front setting and mainly in alkaline conditions. With the burial depth increasing, smectite and kaolinite tended to be transformed into chlorite. Smectite cements were completely transformed into chlorite in sandstones of the studied area. Volcanic lithics rich in Fe and Mg materials were dissolved and released Fe2＋ and Mg 2＋ into the pore water. These cations precipitated as chlorite cements in middle diagenesis in an alkaline diagenetic environment. Chlorite coatings acted as porosity and permeability, thus helping preserve cements in the chlorite cemented sandstones. The reservoir quality of chlorite cemented sandstones is much better than sandstones without chlorite cements. Chlorite cements play an important role in the reservoir evolution that was mainly characterized by preserving intergranular porosity and forming better pore-throat structures of sandstones.
基金Sponsored by National Natural Science Foundation of China(41101078)Natural Science Foundation of Guangdong Province(S2013010014526)+5 种基金General Program of Humanities and Social Science Researches of the Ministry of Education(13YJA790074)Characteristic Innovation Program of Guangdong Provincial Department of Education(2014KTSCX090)2013 Program of the"Twelfth Five-year Plan"of Guangdong Provincial Education and Scientifi c Research(2013JK134)(Second-package)Program of the"Twelfth Five-year Plan"of Guangzhou Municipal Education Science(12A037)the"Twelfth Five-year Plan"of Guangzhou Municipal Philosophy and Social Science(15Q28)2014 Provincial Undergraduate Innovative Training Program of Guangdong Provincial Department of Education(201411078056)
文摘Ecological security of arable land is closely related to grain security and social stability. This paper took 12 typical indexes from the aspects of ecological pressure, state and response of arable land considering natural, social and economic conditions to construct the ecological index system of arable land in Panyu District, Guangzhou City, and adopted objective weighting method and comprehensive analysis method to analyze the dynamic change of ecological security and security level of arable land in the study area. The results showed that ecological security pressure value and response value of arable land in Panyu District from 2008 to 2013 increased and the overall ecological security level was low, manifesting the level of "sensitive–risky–sensitive". Specifi cally, ecological security of arable land in 2008 was sensitive, risky from 2009 to 2011, and the security level rose to the sensitive level again in 2012 and 2013. Ecological restoration and rebuilding of arable land should be enhanced, and ecological security early warning system should be established by protecting quantity and quality of arable land, so as to protect arable land resources effectively, and promote sustainable development of arable land.
