依据全岩XRD衍射、低温氮气吸附实验获取平均孔径、比表面积、绿泥石相对含量等微观储层评价参数,对辽河大民屯凹陷页岩储层分级评价.研究表明: 3 个微观参数彼此之间存在明显的线性关系;平均孔径与绿泥石含量呈线性关系,绿泥石相对含量越髙,平均孔径越大,其主要原因是绿泥石富集化学性质活泼的Fe元素,可吸附大量有机质,有机质在成熟演化阶段可生成大量的有机酸而形成溶蚀孔,并增加储层的平均孔径; 平均孔径与比表面积之间也呈现明显的线性关系,且具有明显的三分性,当平均孔径大于10nm 时比表面积均小于1 m2/ g ,当平均孔径为5~ 10nm 时,比表面积介于1 ~ 6 m2/ g ,当平均孔径小于5nm 时比表面积均大于6m2/g ; 比表面积和绿泥石相对含量两个微观参数之间也呈现出线性关系,且各个拐点之间的参数具有-致性,绿泥石相对含量为5 % 和9 % 时,对应的平均孔径为5 和10nm 、比表面积为6 ~ 1 m2/ g ,可利用该拐点对页岩储层分级评价.
Based on experimental approaches including whole-rock XRD and low-temperature nitrogen adsorption, this researchtargeted three param eters ( average pore size, specific surface area and relative content of chlorite) to establish a gradingsystem for the shale reservoirs in Damintun Depression in Liaohe Oilfield, Northeastern China. The results show that the three microscopic parameters share obvious linear relationship between each other. Higher content of chlorite is usually relatedto larger average pore size. This can be explained that chlorite is rich in Fe , which is chemically active and is capable ofattracting lots of organic matters. The organic matters can subsequently turn into organic acid during the maturing and evolutionprocesses to form numerous solution pores. The study also shows an evident trichotomy in the relationship between averagepore size and specific surface a re a: when the average pore size is more than 10nm ,the associated surface area is lessthan 1 m2/ g ; W hen the average pore size ranges between 5 and 10nm ,the specific surface area varies between 1 m2/ g and6 m-/ g ; and lastly when the average pore size is less than 5nm , the specific surface area is more than 6 m2/g . Microscopicparametersbetween specific surface areas and the relative content of chlorite also show clearly linear relation. Consistenciesare observed between turning points: relative content of chlorite(5% and 9% ) , average pore size (5 nm and 10 nm ) , andspecific surface area ( 6 - 1 m2/ g ) . The turning points can be used to grade the quality of microspore structures in shale reservoirs.