Laboratory Pulse Test of Hydraulic Fracturing on Granitic Sample Cores from Äspö HRL, Sweden
- 289 Downloads
An extensive hydraulic fracturing monitoring experiment in hard rock is conducted at 410 m depth in the Äspö Hard Rock Laboratory (HRL), Sweden, and details are described by Zang et al. (2017). Three different water injection schemes (continuous, progressive and pulse injection) are used to propagate fractures from a horizontal, ca 30-m-deep, 4-inch-diameter diamond-drilled borehole starting at the wall of the experimental tunnel TASN and drilled in the direction of the least horizontal stress. An extensive array of acoustic emission and micro-seismic instruments is installed in long boreholes surrounding the injection borehole. From totally six hydraulic tests with different injection schemes, fracture are generated and extended 20–40 m2into the hard fractured rock mass. Results from three water injection tests and one pulse test show that fracture breakdown pressure becomes lower and the number of fluid-induced seismic events becomes less compared to conventional...
KeywordsHydraulic fracturing Pulse hydraulic fracturing Bi-axial testing Granitic rocks
We acknowledge the technical assistance of O Vanecek, Industrial Safety Assessment Technique, ISATech, Prague, Czech Republic.
- Ask D (2003) Evaluation of measurement-related uncertainties in the analysis of overcoring rock stress data from Äspö HRL, Sweden: a case study. Int J Rock Mech Min Sci 40(7–8):1173–1187Google Scholar
- Jiráková H, Frydrych V, Vintera J, Krasny O, Vanecek M (2015) Results of the rock hydraulic fracturing research project. Tunel Undergr Constr Mag Czech Tunn Assoc Slovak Tunn Assoc 24(4):57–64Google Scholar
- Klee G, Rummel F (2002) IPR-02-02 Rock stress measurements at the Äspö HRL Hydraulic fracturing in boreholes, Tech. rep., SKB, Stockholm, SwedenGoogle Scholar
- Patel SM, Sondergeld CH, Rai CS (2017) Laboratory studies of hydraulic fracturing by cyclic injection. Int J Rock Mech Min Sci 95:8–15Google Scholar
- Zang A, Stephansson O, Stenberg L, Plenkers K, Specht S, Milkereit C, Schill E, Kwiatek G, Dresen G, Zimmermann G, Dahm T, Weber M (2017) Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array. Geophys J Int 208(2):790–813CrossRefGoogle Scholar
- Zhuang L, Kim K, Jung S, Diaz M, Park S, Zang A, Stephansson O, Yoon JS (2016) Laboratory study on cyclic hydraulic fracturing of Pocheon granite in Korea. In: 50th US rock mechanics/geomechanics symposium, 26–29 June 2016. pp 16–163, American Rock Mechanics Association, Houston, Texas, USAGoogle Scholar