超临界流体对生油岩烃类抽提研究

EXTRACTION OF HYDROCARBONS FROM SOURCE ROCKS BY SUPERCRITICAL FLUID

超临界抽提是近年应用于有机地球化学和沉积岩中烃类抽提的一种新方法。笔者应用这一方法于东营凹陷沙四段卜部生油岩的研究结果表明，超临界抽提能有效地革取生油岩中的烃类。已见的文献报道以ＣＯ２为超监界流体对生油岩抽提的结果，超监界抽提物总量较索氏（Ｓｏｘｈｌｃｔ）溶剂抽提物总量要少、但是在笔者的实验中在ＣＯ２里加入１％的异丙醇，却得到超临界抽提物总量较索氏溶剂抽提物总量多若干倍的结果，表现在低成熟生油岩中更甚。这一实验结果在准确评价生油岩生烃能力和资源量计算上可能具有重要的意义。

Supercritical fluid extractions (EFS) ig recently a new method that is applied to organicgeochemistry and extraction of hydrocarbons from sedimemtary rocks.Authors use this method under conditions of pressure 24 MPa, temperature 50℃,extracing take 1 hour with the SFX 2- 10 extractor of ISCO corporation for studing source rocks of Dongying depresion and gain the result that forge quanities of hydrocarbons are extracted from the rocks. In published papers, the extracted quantities by using CO2 as the supercritical fluid are less than the quantities of Soxhlet extraction (SE). But in our experiments when one percent of isopropanol is added into CO2,the contrary results are gained that the extracted quantities are Several times over the amount of Soxhlet extraction. Because the experimental temperature is lower than that of the kerogen thermal degradation,authors think that a large part of hydrocabons,which Soxhlet method cannot extract from the rocks while supercritital extraction can, might not be the products of kerogen to further thermal degradation in the extracting processes whereas is original hydrocarbons easting in the micro-pore or supermicro-pore in the Tocks and being difficultly extracted by Soxhlet extraction. Authors suggest that the viscosity and diffusion coefficients of supercritical fluids are lower than these of solvent (orliquids),so that these original hydrocarbons can be extracted from the rocks. On the other hand, it is of considerable interest that the greater extracted quantities of immature hydeocarbon gource rocks by supercritical fluid extraction than by Soxhlet extraction is far over those of mature source rocks. Comparing the results of Supercritical fluid extraction with those of Soxhlet extraction,we see that superxritical fluid extraction may have an important significance in evaluating the hydrocarbon - generating potentials of sours rocks and computing the amounts of resources in oil-gasing, especially with regard to the shallow-buried and immature source rocks. Since the eatfons Of cd-gaS resources are usthay bud on the results Of Soxhlet extractal, we would say that the oil-gas eted by the resultS of supercritiCal llch (CO2+isopropanol)extractal couki be much more aPProximate to the correCt ware of the ewiuatbos than by those Of Soxhlet extraction.