Passive characterization of hydrofracture properties using signals from the hydraulic pumps
- Univ. of Berkeley, CA (United States)
In this study we utilize conical shear wave arrivals recorded in geophone observation wells to characterize a hydrofracture performed in the South Belridge Diatomite oil field. The conical wave arrivals are initially created by the hydraulic pumps on the surface, which send tube waves down the treatment borehole. Since the tube wave velocity in the Diatomite is greater than the shear formation velocity (the shear velocity in the diatomite is about 2,200 ft/s) cortical shear waves are radiated into the formation by the tube waves traveling down the treatment borehole. We use the decrease in amplitude of the tube wave as it passes through the fracture zone to image changes in hydraulic conductivity of the fracture. By combining this information with estimates of the fracture height we obtain estimates of fracture width changes over time using the model of Tang and Cheng (1993). We find an excellent qualitative agreement between tube wave attenuation and pump pressure over time. Fracture widths estimated from the Tang and Cheng model appear to be consistent with the volume of injected fluid and the known length of the hydrofracture. Provided a monitor well can be instrumented, this technique holds potential for obtaining a relatively inexpensive real-time characterization of hydrofracs.
- OSTI ID:
- 542842
- Report Number(s):
- CONF-951013-; TRN: 97:004463-0030
- Resource Relation:
- Conference: SEG `95: 65. annual meeting and international exposition of the Society of Exploration Geophysicists (SEG), Houston, TX (United States), 8-13 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of SEG/Houston `95 - technical program; PB: 1623 p.
- Country of Publication:
- United States
- Language:
- English
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