Study of thermochemical sulfate reduction of different organic matter: Insight from systematic TSR simulation experiments
Study of thermochemical sulfate reduction of different organic matter: Insight from systematic TSR simulation experiments
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DOI：
10.1016/j.marpetgeo.2018.11.009
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发表时间：
2019-02
影响因子：
4.2
通讯作者：
Heng Zhao;Wenhui Liu;Tenger Borjigin;Jianyong Zhang;Houyong Luo;Xiaofeng Wang
中科院分区：
文献类型：
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作者：
Heng Zhao;Wenhui Liu;Tenger Borjigin;Jianyong Zhang;Houyong Luo;Xiaofeng Wang
针对不同有机质（原油、固体沥青、II型干酪根、III型干酪根）和不同硫酸盐种类（硬石膏和MgSO4）进行了一系列热化学硫酸盐还原（TSR）模拟实验，以解决碳氢化合物、H2S和CO2的化学和碳同位素变化。从对照处理到相应的硫酸盐处理，残余饱和烃主峰碳的增加和气态烃的减少表明TSR促进了液态和气态烃的消耗。 δ13C1-3值通常从对照处理向硫酸盐处理正向移动，并且硫酸盐处理中的(δ13C乙烷-δ13C甲烷)值高于对照处理。 TSR 中δ13C1-3 的变化受TSR 中C1-3 生成和消耗过程中同位素分馏的控制。在 TSR 中，MgSO4 比硬石膏更具反应性。由于二次蚀变，一定量的 H2S 被掺入固体沥青中。我们认为TSR中不同有机质的反应性顺序为原油>固体沥青>II型干酪根>III型干酪根。 TSR 中有机质的反应性取决于每种有机质的生烃动力学。碳酸盐的溶解/分解和沉淀控制着酸性储层中CO2的产量。随着TSR程度的增加，δ13CO2的负移主要是由于碳氢化合物碳同位素的遗传效应。碳酸盐矿物热分解或酸溶解产生的无机CO2 对δ13CO2 有显着影响。 H2S 产率随着 CH4 产率的增加而降低，随着 δ13CH4 值的增加而增加，δ13CH4 值随着气态烷烃残留量 (1- H2S/(残留烷烃 + H2S)) 的增加而增加，表明甲烷在 TSR 中充当反应物。随着温度的升高，(δ13CO2-δ13CH4)值显着降低，且在450°C MgSO4处理的II型和Ⅲ型干酪根中，δ13CO2甚至比δ13CH4更负。因此，在我们的实验中，甲烷是 450°C 硫酸盐处理中的主要反应物。气体干燥度高的天然气在地质储层中可能会经历以甲烷为主的 TSR。
A series of thermochemical sulfate reduction (TSR) simulation experiments were carried out involving different organic matter (crude oil, solid bitumen, type II kerogen, type III kerogen) and different sulfate species (anhydrite and MgSO4) to address the chemical and carbon isotopic variations of the hydrocarbon, H2S and CO2. The increase of main peak carbons of residual saturated hydrocarbon and the decrease of gaseous hydrocarbons from control treatment to corresponding sulfate treatments suggest that TSR promote the consumption of both liquid and gaseous hydrocarbons. The δ13C1-3values generally shift positively from control treatment to sulfate treatments and the (δ13Cethane-δ13Cmethane) values in sulfate treatments are higher than that in control treatments. The variation of δ13C1-3in TSR is controlled by the isotope fractionation during the generation and consumption of C1-3in TSR. MgSO4is more reactive than anhydrite in TSR. A certain amount of H2S is incorporated into solid bitumen as the result of secondary alteration. We believe that the reactivity order of different organic matter in TSR is crude oil > solid bitumen > type II kerogen > type III kerogen. The reactivity of organic matter in TSR depends on the hydrocarbon generation kinetics of each organic matter. The dissolution/decomposition and precipitation of carbonate control the yield of CO2in sour reservoirs. The negative shift of δ13CO2with increasing TSR extent is mainly due to the inheritance effect of carbon isotope from hydrocarbons. Inorganic CO2sourced from the thermal decomposition or acid dissolution of carbonate mineral impose significant influence on δ13CO2. The H2S yields decrease with CH4yields and increase with δ13CH4value, the δ13CH4values increase with residual amount of gaseous alkane (1- H2S/(residual alkane + H2S)), suggesting that methane acted as reactant in TSR. The (δ13CO2-δ13CH4) values decrease significantly with increasing temperature, and the δ13CO2is even more negative than δ13CH4in 450 °C MgSO4treatments involving type II and type Ⅲ kerogen. Accordingly, methane acted as a predominant reactant in 450 °C sulfate treatments in our experiment. It is possible for natural gas with high gas dryness to experience methane-dominated TSR in geological reservoirs.