烃源岩中可溶有机质与粘土矿物结合关系——以东营凹陷沙四段低熟烃源岩为例

STUDY OF COMBINATION PATTERN OF SOLUBLE ORGANIC MATTERS AND CLAY MINERALS IN THE IMMATURE SOURCE ROCKS IN DONGYING DEPRESSION,CHINA

采用超临界抽提（ＳＦＥ）新技术和氯仿抽提（ＣＥ）以及粘土分离等手段对东营凹陷沙四段低熟油烃源岩进行不同处理，得到３种粘土样品：（１）含有机质的粘土原样；（２）氯仿抽提去有机质的样品；（３）不同实验条件下超临界抽提后的样品。然后，分别对这３种粘土样品进行Ｘ射线衍射分析（ＸＲＤ）和傅利叶转换红外光谱分析（ＦＴ－ＩＲ）。研究发现烃源岩中可溶有机质除了吸附于矿物表面外，还吸附于粘土矿物尤其是蒙皂石层的层间，后者主要为碳数相对较低的饱和烃类。这一发现对认识沉积岩中可溶有机质对粘土矿物结构和特性的影响有着重要意义。

The new technique of supercritical fluid extraction (SFE),chloroform extraction (CE) and acid treatment are used to remove soluble organic matters and carbonates from the immature source rocks of the Dongying depression,and three types of clay fractions are obtained:(1)intact organic matter bearing clays,(2)CE teated clays,and (3)clays treated by SFE under different pressures and temperatures.These different clays are then analyzed by X ray diffraction and Fourier transform infrared spectrometer (FT IR),and the organic extracts are measured by gas chromatography(GC).It is revealed that the soluble organic matters,especially low molecular weight hydrocarbon,could be adsorbed in interlamellar space of swelling clay minerals,and on mineral surfaces as well. This discovery could be of great significance in the resource assessment and many other research aspects,such as diagenesis of clay,hydrocarbon generation,primary migration of hydrocarbon in clayey rocks and so on.