Propagation Characteristics of Supercritical Carbon Dioxide Induced Fractures under True Tri-Axial Stresses

Energies

Jiawei Liu¹  Feng Liu¹  Hao Chen¹  Yong Kang¹  Yi Hu²  Yuqiang Hu³ 

[1] Hubei Key Laboratory of Waterjet Theory and New Technology, Wuhan University, Wuhan 430072, China;State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;Underground Gas Store Management Agency of Huabei Oilfield Company, Renqiu 062550, China;

关键词: sc-co₂ fracturing;    fracture propagation;    acoustic emission;    shale;   

DOI  :  10.3390/en12224229

来源: DOAJ

【 摘 要 】

Supercritical carbon dioxide (SC-CO₂) fracturing is a non-aqueous fracturing technology, which has attracted considerable attention on exploiting shale gas. In this study, shale specimens and artificial sandstone specimens were used to conduct SC-CO₂ fracturing and water fracturing experiments to investigate the characteristics of SC-CO₂ induced fractures. An acoustic emission (AE) monitoring device was employed to monitor the AE energy release rate during the experiment. The experiment results indicate that the breakdown pressure of SC-CO₂ fracturing is lower than that of water fracturing under the same conditions, and the AE energy release rate of SC-CO₂ fracturing is 1−2 orders of magnitude higher than that of water fracturing. In artificial sandstone, which is homogeneous, the main fracture mainly propagates along the directions perpendicular to the minimum principal stress, no matter if using SC-CO₂ or water as the fracturing fluid, but in shale with weak structural planes, the propagation direction of the fracture is controlled by the combined effect of a weak structural plane and in-situ stress.

【 授权许可】

Unknown