定量评价五峰-龙马溪组页岩游离气和吸附气含量

Advances in Geo-Energy Research, 2019, 3(3): 258-267

原文网址: https://www.yandy-ager.com/index.php/ager/article/view/139 

       定量评价页岩储层中的游离气和吸附气含量是实现页岩气高效勘探开发的基础。基于甲烷等温吸附的Langmuir体积模型，通过温度和压力的校正可以定量计算游离气和吸附气含量。然而，页岩储层矿物成分非均质性较强，且不同矿物组分对页岩吸附能力影响较大，因此在未考虑矿物组分情况下计算的页岩含气性与实际的页岩气含量差异较大。

       基于灰色关联法，中国地质大学(武汉)苟启洋和徐尚在综合考虑页岩吸附量与温度，压力，有机碳含量，石英和粘土矿物含量关系的基础上，动态校正了Langmuir体积和Langmuir压力等关键参数，建立了计算吸附气体和游离气含量的新模型。结果表明，该模型不仅适用于构造稳定区，还适用于构造运动强烈地区的含气量分析，可作为页岩气井勘探开发潜力分析和预测的指标。

Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China

Qiyang Gou, Shang Xu

(Published: 2019-06-16)

Corresponding Author and Email:

Shang Xu, xushang0222@163.com; 

ORCID: https://orcid.org/0000-0001-6783-3961

Citation: Gou, Q., Xu, S. Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China. Advances in Geo-Energy Research, 2019, 3(3): 258-267, doi: 10.26804/ager.2019.03.04.

ArticleType: Original article

Abstract：

    Quantitative analysis of free gas and adsorbed gas contents in shale reservoirs are great significance for efficient exploration and development of shale gas. Based on the isothermal adsorption experiment of shale samples from Wufeng-Longmaxi Formation of JYA well in Jiaoshiba area and Langmuir volume model, the relationship between shale adsorption capacity and temperature, pressure, organic carbon content, quartz and clay mineral content is analyzed. Besides, the key parameters such as Langmuir volume and Langmuir pressure are dynamically calibrated by combining grey correlation method. A new model for calculating adsorbed gas and free gas is established, which takes fully into account the formation temperature, pressure, total organic carbon and shale mineral components. The results showed that the gas content of shale calculated by the new dynamic modified model is in good agreement with the actual gas content characteristics of shale reservoirs. The new model fully takes into account the vertical and horizontal heterogeneity of mineral components and its influence on shale adsorption capacity. That is not only suitable for the tectonic stability area but also for the gas content analysis in the area with strong tectonic movement. It is concluded that the modified calculation model can effectively predict the adsorbed gas, free gas and total gas content of shale reservoirs under formation conditions, which can be used as an indicator for the analysis and prediction of the exploration and development potential of shale gas wells.

Keywords: Shale gas, free gas, adsorbed gas, gas content, isothermal adsorption, Jiaoshiba area.

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