## Abstract

In order to discuss the method for estimating the geometric characteristics of geothermal reservoir cracks, a theoretical study is performed on the dynamic response of the fluid inside a reservoir crack in a rock mass subjected to a dynamic excitation due to propagation of an elastic wave. As representative models of reservoir cracks, a penny shaped crack and a two-dimensional crack which are connected to a borehole are considered. It is found that the resonance frequency of the fluid motion is dependent on the crack size, the fluid's viscosity and the permeability of the formation. The intensity of the resonance is dependent on the fluid's viscosity when the size, the aperture and the permeability are fixed. It is also found that, at a value of the fluid's viscosity, the resonance of fluid pressure becomes strongest. The optimum value of the fluid's viscosity is found to be almost perfectly determined by the permeability of the formation. Furthermore, it is revealed that, if the fluid's viscosity is fixed to be the optimum value, the resonance frequency is almost independent of the permeability and aperture, but is dependent on the size of crack. Inversely speaking, this implies that the size of the reservoir crack can be estimated from the resonance frequency, if the fluid with the above mentioned optimum value of viscosity is employed for hydraulic fracturing.

Original language | English |
---|---|

Pages (from-to) | 577-583 |

Number of pages | 7 |

Journal | Transactions - Geothermal Resources Council |

Volume | 21 |

Publication status | Published - 1997 Dec 1 |

Event | Proceedings of the 1997 Annual Meeting of the Geothermal Resources Council - Burlingame, CA, USA Duration: 1997 Oct 12 → 1997 Oct 15 |

## ASJC Scopus subject areas

- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Geophysics