Seismic monitoring of hydraulic fracturing: techniques for determining fluid flow paths and state of stress away from a wellbore

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5876732

Fehler, M; House, L; Kaieda, H

Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and idependently confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional well logging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we believe that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrincis rock properties.

• Research Organization: Los Alamos National Lab., NM (USA); Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Technical Lab. No. 2
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5876732
• Report Number(s): LA-UR-86-785; CONF-860609-7; ON: DE86007365
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580203* -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ACOUSTIC MONITORING
COMMINUTION
EARTHQUAKES
FRACTURING
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
HYDRAULIC FRACTURING
MICROEARTHQUAKES
MONITORING
ORIENTATION
ROCKS
SEISMIC EVENTS
STRESSES