Experience with hydraulic fracturing tests for stress measurements in the WIPP
Hydraulic fracturing tests around the WIPP in the Salado salt formation near Carlsbad, New Mexico, demonstrated that the virgin in situ stress state is isotropic and that the stress magnitude corresponds to the weight of the overburden. It was also determined, however, that hydraulic fracturing in rock salt does not render stress measurements directly because all characteristic test pressures are strongly influenced by creep. In this study, the correlation between fracturing pressures and in situ stresses was made by means of finite element analyses and by means of in situ observations of all hydraulically induced fracture patterns. Because of creep, it also appears that the shapes of the pressure-time records in rock salt will be very different from the normal shapes of hydraulic fracturing records in competent hard rock. In particular, (1) stable pressure-time signatures with no distinct change from breakdown to driving pressures are obtained under isotropic far-field loading, (2) instantaneous shut-in pressures are likely to be obscured by fracture pinching, and (3) pressure-time signatures will change with delay time between drilling and hydraulic fracturing for approximately the first 50 days. After that time, a relatively long window appears to open up during which the predicted stress fields around the drillhole are approximately constant. The present results should apply qualitatively to hydraulic fracturing at other sites. However, local differences such as brinehead pressures should be taken into account.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5800322
- Report Number(s):
- SAND-85-2273C; CONF-860609-4; ON: DE86007388
- Country of Publication:
- United States
- Language:
- English
Similar Records
Application of hydraulic fracturing to determine virgin in situ stress state around Waste Isolation Pilot Plant - in situ measurements
Hydraulic fracturing tests in anhydrite interbeds in the WIPP, Marker Beds 139 and 140
Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
COMMINUTION
DATA
EXPERIMENTAL DATA
FRACTURING
FUNCTIONAL MODELS
GEOLOGIC DEPOSITS
HYDRAULIC FRACTURING
INFORMATION
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
NUMERICAL DATA
PILOT PLANTS
RADIOACTIVE WASTE FACILITIES
SALT DEPOSITS
STRESSES
UNDERGROUND FACILITIES
US DOE
US ORGANIZATIONS
WIPP