【作者】 徐庆霞；

【导师】 卢双舫；

【作者基本信息】 大庆石油学院 ， 地球化学， 2008， 硕士

【摘要】 为了分析水在有机质热裂解成气过程中的作用,考察加水量和水介质性质对烷烃气碳同位素分馏的影响,本文采用黄金管热模拟装置,选取纯化合物正十八烷加不同比例的蒸馏水和加水比例相同但不同的水介质进行热模拟实验,通过新的实验和系统的分析,得到一些认识和结论:(1)热模拟实验中水的存在增加了烃气的产率和稳定性,十八烷加水实验中生成大量CO2和H2,排除含水实验中CO和H2O发生水煤气反应及C与H2O发生反应造成CO2和H2产率增加的可能,证明水参与了十八烷热裂解生烃的反应。反应物中加水比例越大,上述效应越明显;(2)水介质中溶解的无机盐类能够催化有机质热裂解生烃气和CO2、H2;(3)加水与无水条件下n-C18H38裂解生成的甲烷碳同位素分馏整体差别较小,因此用有机质无水与加水热裂解模拟地质条件下的有机质热裂解生甲烷的碳同位素分馏或将其外推到地质情况下进行应用,二者的差别可能很小;(4)水介质性质对十八烷热裂解生成的烷烃气碳同位素分馏基本没有影响;(5)加水实验的CO2在生成过程中相对其他烷烃气碳同位素分馏来说不存在明显的动力学碳同位素分馏现象。为避免反应母质同位素分布的非均质性对有机质热裂解生气态烃碳同位素分馏的影响,选取含不同官能团的纯化合物n-C18H38、十八酸、十八胺、十氢化萘、9-苯基蒽进行热模拟实验,从实验的角度得出影响热成因甲烷碳同位素分馏的因素主要有:(1)温度;(2)各化合物热裂解生甲烷过程中存在的反应机制;(3)反应有机质的初始碳同位素组成。最后,将有机质热裂解生甲烷碳同位素分馏的化学动力学模拟在徐家围子断陷地区进行了简单的地质应用,得到徐深1井区源岩对该井区气藏的贡献比例约占66%,沉降中心源岩的贡献比例约为34%。更多还原

【Abstract】 In order to analyze the role of water playing in the pyrolysis process of organic matter and investigate how the added water quantity and quality affect the alkane gas carbon isotope fractionation, this paper adopts the gold tube pyrolysis setting, and select the pure n-C18H38 to add distilled water in different n-C18H38 to water ratio and to add three kinds of water with different quality in the same n-C18H38 to water ratio to perform experiments. Through new experiments and systematic analyses, we get something new and conclusions.(1)The added water increases the yield of hydrocarbon gas and stabililty. The increase yield of CO2 and H2 caused by reactions between CO and H2O and between C and H2O are excluded. Quantity of CO2 and H2 reflect that water reacts with the organic matter in the pyrolysis process. The more the water occupies in the reactants, the more obvious of the above effect. (2)The resolved inorganic salt in water can catalyze the organic matter to pyrolyze into alkane gases, CO2 and H2. (3)Water can affect methane isotope fractionation in the process of n-C18H38 pyrolysis, and the influence is small. So the difference is very small whether use organic thermally cracking experiments without water or with water to simulate carbon isotope fractionation of methane in geological condition, and the difference is also small if the kinetic parameters of carbon isotope fractionation were applied to geological conditions. (4)The carbon isotope fractionation of alkane gas is almost not changed by different quality water. (5)Compared to carbon isotope ration of alkane gas, the carbon isotope fractionation phenomena of CO2 does not exist obviously in the hydrous thermally cracking process.In order to avoid the influence to carbon isotope fractionation of alkane gas by the isotopic heterogeneity of reactants, five kinds of pure compounds that are n-C18H38, stearic acid, octadecylamine, decahydronaphthalene dekalin,9-phenyl anthrecene are selected to do thermally cracking experiments. By comparing and analyzing the influencing factors to carbon isotope fractionation of thermal cracking methane of organic matters are summarized as follows: (1)temperature. (2)the existing reaction mechanisms in the thermal cracking process of different compounds. (3)the carbon isotope ratio of the reactant.At the end the kinetic parameters of carbon isotope fractionation of methane calculated from the organic thermally cracking into methane experiments are simply applied to Xujiaweizi fault depression. The result is that 66% of the gas reservoir of Xushen 1 well is from the source rock near Xushen 1 well, and 34% is from the depocenter stratum.更多还原