Modeling of gas generation from the Barnett Shale, Fort Worth Basin, Texas
Modeling of gas generation from the Barnett Shale, Fort Worth Basin, Texas
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DOI：
10.1306/12060606063
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发表时间：
2007-04-01
期刊：
影响因子：
3.5
通讯作者：
Tang, Yongchun
中科院分区：
文献类型：
--
作者：
Hill, Ronald J.;Zhang, Etuan;Tang, Yongchun
采用密闭金管热解法对德克萨斯州沃斯堡盆地密西西比系巴内特页岩的生气潜力进行了定量评价。根据热解数据计算了气体生成和镜质体反射率（Ro）变化的动力学参数，并将结果用于估计地质加热速率下巴内特页岩生成的气体量。使用导出的R-o演化和气体生成的动力学，对于初始总有机碳含量为5.5%且R-o = 0.44%的样品，在R-o类似于1.1%时生成的烃气体的量为约230 L/t（7.4 scf/t），并且在R-o类似于2.0%时增加至大于5800 L/t（186 scf/t）。生成的页岩气的体积将取决于页岩的有机丰度、厚度和热成熟度，以及在迁移期间保留在页岩中的石油的量。页岩中的天然气似乎是由页岩中保留的油母岩和石油的裂解产生的，并且保留的石油的裂解开始于R-o 1.1%。这一结果表明，裂解的石油保留在源岩发生的速度比传统的硅质岩和碳酸盐岩储层预测的速度更快，并保留的石油与油母质和页岩矿物学的接触可能是页岩气生成的关键因素。页岩气系统与上覆岩层一起可以被认为是完整的含油气系统，尽管石油运移、聚集和圈闭形成的过程与常规含油气系统的定义不同。
The generative gas potential of the Mississippian Barnett Shale in the Fort Worth Basin, Texas, was quantitatively evaluated by sealed gold-tube pyrolysis. Kinetic parameters for gas generation and vitrinite reflectance (R-o) changes were calculated from pyrolysis data and the results used to estimate the amount of gas generated from the Barnett Shale at geologic heating rates. Using derived kinetics for R-o evolution and gas generation, quantities of hydrocarbon gas generated at R-o similar to 1.1% are about 230 L/t (7.4 scf/t) and increase to more that 5800 L/t (186 scf/t) at R-o similar to 2.0% for a sample with an initial total organic carbon content of 5.5% and R-o = 0.44%. The volume of shale gas generated will depend on the organic richness, thickness, and thermal maturity of the shale and also the amount of petroleum that is retained in the shale during migration. Gas that is reservoired in shales appears to be generated from the cracking of kerogen and petroleum that is retained in shales, and that cracking of the retained petroleum starts by R-o 1.1 %. This result suggests that the cracking of petroleum retained in source rocks occurs at rates that are faster than what is predicted for conventional siliciclastic and carbonate reservoirs, and that contact of retained petroleum with kerogen and shale mineralogy may be a critical factor in shale-gas generation. Shale-gas systems, together with overburden, can be considered complete petroleum systems, although the processes of petroleum migration, accumulation, and trap formation are different from what is defined for conventional petroleum systems.