论文部分内容阅读
为了研究不同类型原油和源内残余沥青在高演化阶段的甲烷产率,明确天然气成因类型,系统整理了不同类型原油及源岩的金管模拟实验结果,统计了甲烷产率随模拟温度的变化,发现原油性质对生气过程和生气量都有明显控制,重质油起始生气温度低于轻质油和正常油,在原油裂解成气初期,甲烷产率变化为重质油>正常原油>轻质油,重质油对天然气成藏贡献较大;在原油大量裂解过程中,轻质油的甲烷产率很快超过正常原油和重质油,最终成为天然气成藏的主力。重质油产气早是因为其富含非烃和沥青质,裂解活化能低,产气率低与H/C值(原子比)低有关,轻质油产气晚是因为其富含饱和烃,裂解活化能高,产气率高与H/C值(原子比)高有关。轻质油开始裂解对应成熟度约为Easy%R_O=1.5%。干酪根及源内分散沥青生气与原油裂解受相同的因素控制,H/C值高低控制了不同类型干酪根的生气量,在各成熟阶段上甲烷产率始终是Ⅰ>Ⅱ>Ⅲ型有机质。源内分散沥青在化学组成上接近重质油,但比重质油更容易裂解,除活化能低外,还受到黏土矿物催化的影响,其起始裂解成熟度大体为Easy%R_O=1.0%。这种差异对热演化程度极高的四川盆地天然气成因类型确定和潜力评价有非常重要的地质意义。
In order to study the methane production rate of the residual bitumen in different types of crude oil and source in the high evolution stage and clarify the type of gas genesis, the gold tube simulation results of different types of crude oil and source rocks were systematically sorted out. The variation of methane yield with simulated temperature was found The nature of crude oil has obvious control on the process of gas generation and gas generation. The initial gas temperature of heavy oil is lower than that of light oil and normal oil. At the initial stage of crude oil cracking into gas, the methane yield changes from heavy oil> normal crude oil> Oil and heavy oil contributed greatly to the accumulation of natural gas. In the process of massive cracking of crude oil, the yield of methane of light oil surpassed that of normal crude oil and heavy oil and eventually became the main force of natural gas accumulation. Heavy oil gas production is due to its high content of non-hydrocarbon and asphaltene, low activation energy of cracking, low gas production rate and low H / C value (atomic ratio), and light oil gas production is due to its high saturation Hydrocarbon, high activation energy of cracking, high gas production rate and H / C value (atomic ratio) high. Light oil began to crack corresponding to the maturity of about Easy% R_O = 1.5%. The generation of kerogen and crude oil cracking in kerogen and source were controlled by the same factors. The H / C value controlled the gas generation of different types of kerogen, and the methane production rate was always> Ⅰ> Ⅱ> Ⅲ in all mature stages. In-situ dispersed bitumen is similar in chemical composition to heavy oil, but it is easier to crack than heavy oil. In addition to its low activation energy, it is also affected by the catalysis of clay minerals. The initial cracking maturity is generally Easy% R_O = 1.0%. This difference has a very important geological significance for determining the type of natural gas and for evaluating the potential of natural gas in the Sichuan Basin, which has a very high degree of thermal evolution.