Difference between excess and absolute adsorption capacity of shale and a new shale gas reserve calculation method

被引：0
作者：
Zhou S. [1 ,2 ,3 ]
Wang H. [1 ,2 ,3 ]
Xue H. [1 ,2 ,3 ]
Guo W. [1 ,2 ,3 ]
Lu B. [1 ,2 ,3 ]
机构：
[1] Langfang Branch of PetroChina Exploration & Development Research Institute, Langfang, 065007, Hebei
[2] National Energy Shale Gas R&D <Experimental> Center, Langfang, 065007, Hebei
[3] CNPC Key Laboratory of Unconventional Oil & Gas, Langfang, 065007, Hebei
来源：
Natural Gas Industry | 2016年 / 36卷 / 11期
关键词：
Absolute adsorption capacity; Adsorbed phase density; Excess adsorption capacity; Geological reserves; Gravimetric method; Isothermal adsorption; New calculation method; Shale gas; Supercritical condition;
D O I：
10.3787/j.issn.1000-0976.2016.11.002
中图分类号：
学科分类号：
摘要：
The accurate measurement of adsorbed shale gas content is quite significant to reserve evaluation and development plan preparation. However, the difference between excess and absolute adsorption capacity was not taken into account before when the adsorbed gas content in reservoir conditions was calculated. In this paper, a series of analysis was carried out according to isothermal adsorption experiment principles based on gravimetric method. It is shown that, when adsorbed phase volume is taken into account, the absolute methane adsorption capacity cannot be measured directly through the isothermal adsorption experiment, and the measured value is actually the excess adsorption capacity; and that the excess adsorption capacity reaches the maximum value when the pressure is up to about 10 MPa, and then it decreases with the increase of pressure. This phenomenon is the essential characteristic of excess adsorption capacity of supercritical methane. An improved method for calculating the adsorbed phase density of methane was proposed to convert the excess adsorption into the absolute adsorption. The improved method is better fitted with the adsorption experiment data, and the calculated adsorbed phase density is more reasonable. Then, the absolute adsorption capacity was corrected. It is demonstrated that the difference between the absolute and excess adsorption capacity enlarges along with the pressure. If the experimental adsorption curve under low pressure is directly used for shale adsorption capacity evaluation, the actual adsorption capacity of a shale gas reservoir will be significantly underestimated. In view of this, a new method was proposed to calculate the original shale gas in place by using the excess adsorption capacity and the free gas volume. It is concluded that the shale gas content calculated by the old method is much higher than that of the new method, so the original shale gas in place may be previously overestimated. © 2016, Natural Gas Industry Journal Agency. All right reserved.
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页码：12 / 20
页数：8
相关论文
共 29 条
[1]  
Curtis J.B., Fractured shale-gas systems, AAPG Bulletin, 86, 11, pp. 1921-1938, (2002)
[2]  
Ambrose R.J., Hartman R.C., Diaz-Campos M., Akkutlu I.Y., Sondergeld C.H., Shale gas-in-place calculations part I: New pore-scale considerations, SPE Journal, 17, 1, pp. 219-229, (2012)
[3]  
Gasparik M., Bertier P., Gensterblum Y., Ghanizadeh A., Krooss B.M., Littke R., Geological controls on the methane storage capacity in organic-rich shales, International Journal of Coal Geology, 123, 2, pp. 34-51, (2014)
[4]  
Li Y., Qiao D., Jiang W., Zhang C., Gas content of gas-bearing shale and its geological evaluation summary, Geological Bulletin of China, 30, 2, pp. 308-317, (2011)
[5]  
Nie H., Zhang J., Shale gas accumulation conditions and gas content calculation: A case study of Sichuan Basin and its periphery in the Lower Paleozoic, Acta Geologica Sinica, 86, 2, pp. 349-361, (2012)
[6]  
Liang B., Jiang H., Li J., Mi L., Wang L., Calculation model of multi-factor shale gas adsorption capacity, Special Oil & Gas Reservoirs, 22, 1, pp. 121-123, (2015)
[7]  
Liu H., Wang H., Adsorptivity and influential factors of marine shales in South China, Natural Gas Industry, 32, 9, pp. 5-9, (2012)
[8]  
Jiang G., Fan J., Li Y., Wu L., Zhang Z., Study on new system used for acceleration of shale gas desorption, Special Oil & Gas Reservoirs, 21, 3, pp. 116-119, (2014)
[9]  
Guo W., Xiong W., Gao S., Hu Z., Isothermal adsorption/desorption characteristics of shale gas, Journal of Central South University: Science and Technology, 44, 7, pp. 2836-2840, (2013)
[10]  
Guo W., Xiong W., Gao S., Hu Z., Liu H., Yu R., Impact of temperature on the isothermal adsorption/desorption characteristics of shale gas, Petroleum Exploration and Development, 40, 4, pp. 481-485, (2013)
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