Characteristics of fractures stimulated by supercritical carbon dioxide fracturing in shale based on acoustic emission monitoring

Wu，Shan1,2; Ge，Hongkui2; Li，Tiantai3; Wang，Xiaoqiong2; Li，Ning2; Zou，Yushi2; Gao，Ke1

2022-04-01

10.1016/j.ijrmms.2022.105065

International Journal of Rock Mechanics and Minings Sciences   影响因子和分区

1365-1609

1873-4545

In recent years, supercritical carbon dioxide (SC–CO) has been attempted in hydraulic fracturing in shale reservoirs as a new type of fracturing tool to overcome the drawback of traditional water-based fluids. Because of the unique physical and chemical properties of SC-CO, its fracturing mechanism is more complicated than traditional fluids and still unclear at present. In this paper, we hydraulically fracture a shale reservoir rock using SC-CO and monitor the fracturing process using acoustic emission (AE) data. The results show the fractures stimulated by SC-CO composite of both shear and tensile fractures. In the initiation stage, SC-CO activates the natural fractures around the wellbore and induces shear fractures. In the propagation stage, SC-CO permeates the fracture tips quickly, results in a dynamic propagation process, and generates plenty of tensile fractures. The phase change of CO could be observed during the fracture propagation process, which is accompanied by a rapid pressure change and local stress shock formations in the fractures. Additionally, the experiments also demonstrate that the existence of bedding structures in shale could constrain the propagation of fractures, thus leading to a smaller volume of fracture network and limiting the complexity of the generated fractures. This research may help understand the fracturing mechanism of SC-CO and shed light on the development of hydraulic fracturing technology in shale reservoirs.

SCI ; EI

英语

第一

Strategic Cooperation Technology Projects of CNPC and CUPB["ZLZX2020-01-08","ZLZX2020-01-07"] ; Natural Science Foundation of China[51774236]

Engineering ; Mining & Mineral Processing

Engineering, Geological ; Mining & Mineral Processing

WOS:000774190000003

PERGAMON-ELSEVIER SCIENCE LTD

20220811690208

Acoustic emission testing ; Carbon dioxide ; Fracture ; Fracturing fluids ; Hydraulic fracturing ; Reservoirs (water) ; Shale

Reservoirs:441.2 ; Petroleum Deposits : Development Operations:512.1.2 ; Acoustic Properties of Materials:751.2 ; Chemical Operations:802.3 ; Inorganic Compounds:804.2 ; Materials Science:951

2-s2.0-85124913719

Scopus

1.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,Guangdong,518055,China
2.China University of Petroleum (Beijing),Beijing,102249,China
3.Xi'an Shiyou University,Xi'an,Shanxi,710065,China

Wu，Shan,Ge，Hongkui,Li，Tiantai,et al. Characteristics of fractures stimulated by supercritical carbon dioxide fracturing in shale based on acoustic emission monitoring[J]. International Journal of Rock Mechanics and Minings Sciences,2022,152.

Wu，Shan.,Ge，Hongkui.,Li，Tiantai.,Wang，Xiaoqiong.,Li，Ning.,...&Gao，Ke.(2022).Characteristics of fractures stimulated by supercritical carbon dioxide fracturing in shale based on acoustic emission monitoring.International Journal of Rock Mechanics and Minings Sciences,152.

Wu，Shan,et al."Characteristics of fractures stimulated by supercritical carbon dioxide fracturing in shale based on acoustic emission monitoring".International Journal of Rock Mechanics and Minings Sciences 152(2022).