A discrete element model to link the microseismic energies recorded in caprock to geomechanics

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• 作者：Cyrus Khazaei ; Jim Hazzard ; Rick Chalaturnyk
• 关键词：Caprock integrity ; Carbon capture and storage (CCS) ; Geomechanics ; Microseismic ; Particle Flow Code (PFC3D) ; Weyburn
• 刊名：Acta Geotechnica
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：11
• 期：6
• 页码：1351-1367
• 全文大小：3,152 KB
• 刊物类别：Engineering
• 刊物主题：Continuum Mechanics and Mechanics of Materials
  Geotechnical Engineering
  Soil Science and Conservation
  Granular Media
  Structural Mechanics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1861-1133
• 卷排序：11

文摘

A discrete element model is presented to study slip-induced microseismic events along weak planes and crack-induced microseismic events within the intact rock for a representative elementary volume, REV, in the caprock of Weyburn reservoir. Also, the effect of varying factors such as orientation, coefficient of friction and elasticity of the weak plane on release of microseismic energies is studied. According to the results, for the conditions studied in this paper, the magnitudes of slip-induced events range from ~−1 to −6, while crack-induced events range from ~−7 to −11. Considering the capability of geophones, this suggests that events “recorded” in the caprock are more likely to have slip origins along weak planes than having crack origins within the intact rock. In order to show the applicability of the model in practice, the events recorded in the caprock of Weyburn from September to November of 2010 are analyzed. Also, a simple model is presented that correlates the amount of consumed energy per volume of the REV with the seismic energy released due to stick–slips along a weak plane. The results show that weak planes can be emissive even long before the failure of their surrounding is reached, and therefore, there can be a level of tolerance for the observed microseismic events in the caprock.