Microsismic and Acoustic Activity Associated with Hydraulic Fracture Propagation
Sismic and acoustic sources activated by the development of hydraulic fractures are discussed. It is shown that acoustic activity associated with crack extension should be high frequency; its existence depends upon pressure distribution at crack tip. For permeable fractured material, the increment in pore pressure in the vicinity of the hydraulic fracture may lead to some local slips which, in turn, can generate signals.
The frequency spectrum of these signals depends on the amount of injected volume and injection duration. In situ experiments carried out to investigate the possibility of mapping this activity in order to determine orientation and extent of a hydraulic fracture are presented. By comparison with previously published results, it is concluded that hydrophones are not appropriate for monitoring this type of acoustic activity. Further no low frequency induced seismicity has been observed although up to 12 m3 meters have been injected.
KeywordsPropa Brittle Petrol Azimuth Geophysics
Unable to display preview. Download preview PDF.
- Barenblatt G.I.; 1962; “The mathematical theory of equilibrium cracks in brittle fracture”; Advanced appl. Mech. Vol. 7, p. 55, academic Press.Google Scholar
- Cornet F.H.; 1978; “Application de la fracturation hydraulique à la mesure in-situ des contraintes”; colloque scientifique J.Goguel. B.R.G.M. mémoire n°91.Google Scholar
- Griffith A.A.; 1921; “The phenomenon of rupture and flow in solids”; Phil. Trans. Roy. Soc. London. Vol. A 221.Google Scholar
- Haimson B. and C. Fairhurst; 1969; “In situ stress determination at great depth by means of hydraulic fracturing”, 11th Symp. on Rock Mech., Berkeley. Somerton editor, p. 559.Google Scholar
- Hubbert M.K. and D.G. Willis; 1957; “Mechanics of hydraulic fracturing Petrol”. Trans.A.I.M.E., Vol. 210, p. 153.Google Scholar
- Irwin G.R.; 1957; “Analysis of stresses and strains near the end of a crack traversing a plate”; Jou. App. Mech., Vol 24, p. 361.Google Scholar
- Los Alamos Scientific Laboratory: 1976 — L.A.S.L. Hot Dry Rock Geothermal Project, Progress Report — LA-6525-PR. 1978 — Hot dry rock Geothermal energy development project; progress report for F.Y.1977; LA — 7109 — PR.Google Scholar
- Madariaga R.; 1979; “Seismic Radiation from earthquake models based on fracture mechanics”, S.I.A.M. — Am. Math. Soc. Vol. 12, p. 59.Google Scholar
- Power D.V., Schuster C.L., Hay R. and J. Twombly; 1976; Jou. Petrol. Techn., p. 1116Google Scholar