A dual-site Langmuir equation for accurate estimation of high pressure deep shale gas resources

作者：Tang Xu^*; Ripepi Nino; Stadie Nicholas P; Yu Lingjie; Hall Matthew R

来源：Fuel, 2016, 185: 10-17.

DOI：10.1016/j.fuel.2016.07.088

• Shale gas
• Methane
• Absolute adsorption
• Langmuir

Adsorbed methane makes up a large portion of the total shale gas-in-place (GIP) resource in deep shale formations. In order to accurately estimate the shale GIP resource, it is crucial to understand the relationship between the adsorbed methane quantity and the free methane quantity of shale gas in shale formations (under high pressure conditions). This work describes and accurately predicts high pressure methane adsorption behavior in Longmaxi shale (China) using a dual-site Langmuir model. Laboratory measurements of high pressure methane adsorption (303-355 K and up to 27 MPa) are presented. Our findings show that for depths greater than 1000 m (>15 MPa) in the subsurface, the shale gas resources have historically been significantly overestimated. For Longmaxi shale (2500-3000 m in depth), classical approaches overestimate the GIP by up to 35%. The ratio of the adsorbed phase compared to the free gas has been significantly underestimated. The methods used herein allow accurate estimations of the true shale GIP resource and the relative quantity of adsorbed methane at in situ temperatures and pressures representative of deep shale formations.

• 出版日期2016-12-1