Continuous Monitoring of Crosswell Seismic Travel Time
نویسندگان
چکیده
In two separate shallow field experiments, at two distance scales, we have used continuous monitoring to estimate the effect of barometric pressure on crosswell travel time and thereby calibrated the stress sensitivity of the rock volume between the wells. In a 3 m experiment we found a stress sensitivity of 10/Pa while in a 30 m experiment the sensitivity was 5 x 10 /Pa. Results from a deeper (1 km), 2 month experiment at the San Andreas fault observation boreholes will be presented if analysis is completed.
منابع مشابه
Report 9 Crosswell Imaging with Surface Sources and Tube Waves
Conventional crosswell surveys are expensive because a source must be placed downhole, which means that the hole must be prepped and placed off-line for a number of days. We suggest an interesting but unproven alternative: place a source on the surface, drop a simple obstruction-like device downhole that scatters tube wave arrivals from the surface source, and use the scattered tube waves energ...
متن کاملExtraction of Reflections from Tube Waves
Meng (1997) used the McConnell crosswell data to show that transmitted arrival traveltimes can be extracted from common receiver gathers (CRG) where the effective source is a tube wave generator. In this report I use the McElroy crosswell data to show that reflection events can be extracted from CRG’s where the effective source is a tube wave generator. This result opens the possibility that mo...
متن کاملThe Value of Borehole -to-surface Information in Near-surface Crosswell Seismic Tomography
Detailed information about the spatial distribution of subsurface properties is important in many fields. One method that can image the seismic velocity structure of the shallow subsurface is crosswell seismic tomography. By including rays traveling from the boreholes to the surface, the angular coverage of crosswell tomograms can be significantly improved. We investigated the effects of these ...
متن کاملSharp boundary inversion in crosswell travel-time tomography
Abs tract The reconstruction of seismic images of the medium from cross we ll travel-time data is a typic al examp le of the ill-posed inverse prob lem. In order to obt ain a stable so lution and to rep lace an ill-posed problem by a well-posed one, a stabilizing functiona l (stabilizer) has to be introduced. The ro le of this functional is to select the desired stable so lution from a class of...
متن کاملTemporal Integration Of Seismic Traveltime Tomography
Time-lapse geophysical measurements and seismic imaging methods in particular are powerful techniques for monitoring changes in reservoir properties. Traditional time-lapse processing methods treat each dataset as an independent unit and estimate changes in reservoir state through differencing these separate inversions. We present a general least-squares approach to jointly inverting time-varyi...
متن کامل