中国陆相油页岩特征及成因类型

Characteristics and genetic types of continental oil shales in China

中国油页岩资源丰富,以陆相沉积为主,主要赋存于中新生界,颜色通常为黑色—深灰色和灰褐色—棕褐色,且富矿油页岩一般比贫矿油页岩的颜色深。油页岩中矿物成分以石英、长石和黏土矿物为主,黏土矿物中高岭石含量相对较高。中国陆相油页岩总体质量特征为中等偏好,含油率大于5%的页岩油资源占67.64%,灰分产率一般为53.27%～84.35%,多属高灰分油页岩。发热量各地区差别较大,最小值为4.19MJ/kg,最大值可达34.60MJ/kg,而且同一地区不同层位的油页岩发热量也不相同。就伴生元素而言,油页岩中富含大量的稀土元素和微量元素,使油页岩具有巨大的综合利用潜力。从有机成因角度,中国陆相油页岩可以分为腐泥型油页岩、腐殖腐泥型油页岩和腐泥腐殖型油页岩;从油页岩的沉积环境成因角度,可以划分为拗陷湖成油页岩、断陷湖成油页岩和断陷湖泊—沼泽油页岩;从油页岩形成的水体性质角度,可以划分为淡水油页岩和半咸水油页岩。中国陆相油页岩中湖泊—沼泽油页岩一般与煤伴生,多为腐殖腐泥型油页岩和腐泥腐殖型油页岩;而湖成油页岩一般单独存在或为煤层顶板,多为腐泥型油页岩和腐殖腐泥型油页岩。

China is rich in oil shale resource with the oil shale being dominated by the continental deposition. Oil shale is mainly deposited in the Meso-Cenozoic times and it has black gray-dark gray, grayish brown-brown colors. In most cases, the color of rich oil shale is darker than that of poor oil shale. The mineral compositions of oil shale mainly include quartz, feldspar and clay minerals, and the content of kaolinite in clay minerals is relatively high. The quality of oil shale in China are generally good and the oil shale resource, whose oil yield is more than 5% , makes up 67.64% of the whole oil shale resource. The content of ash is usually between 53.27% and 84.35%, so oil shale belongs to high-ash oil shale. The caloric values of oil shale in each area are different. The minimum caloric value is 4. 19 MJ/kg and the maximum caloric value is 34.60 MJ/kg. Even in the same area, the caloric values of oil shale in different formations are different. As far as associated elements are concerned, oil shale is rich in a lot of rare-earth and trace elements, which makes oil shale having great comprehensive utilization potential. From the perspective of organic genesis, continental oil shale in China can be divided into sapropelic, humosapropelic and saprohumolic oil shale. As for sedimentary environment of oil shale, it can be divided into depressional lacustrine, rift lacustrine and fault limnic oil shale. According to the characteristics of waters where oil shale was deposited, it can be divided into fresh water and brackish water oil shale. Generally, in continental oil shale in China, limnic oil shale usually coexsits with coal, and is mostly humosapropelic and saprohumolic oil shale, while lacustrine oil shale usually exsits alone or as the top layer of coal measure and is mostly sapropelic and humosapropelic oil shale.