Microseismic noise suppression is widely used in the exploration of unconventional oil and gas resources. The effective microseismic downhole signals have extremely weak energy are contaminated by strong interference, making data processing interpretation difficult. need for high-frequency signal reservation presents a basic problem design methods. represent as continuous reflection event more ...

Receiver function is defined as the spectral ratio of the radial component and the vertical component of the ground motion. It is used to characterize converted waves. We extend the use of the receiver function to downhole data using waves recorded in a borehole, excited by an earthquake of magnitude 4.0 near San Francisco, California, on 26 June 1994. The focal depth of the event was 6.6 km an...

Approximate and exact formulations are presented for the interaction of an incident wave with a cased borehole. In the approximate method, the borehole coupling theory is used to compute pressure in the fluid at a low frequency. The results are simple and explicit. They are useful in the study of cased borehole coupling and as well as borehole radiation. In the exact method, elastic potentials ...

A three-level downhole array is being operated in a 1500-m-deep borehole within the seismically active Newport-lnglewood fault zone, Los Angeles basin. The array consists of three three-component 4.5 Hz seismometers deployed at the surface, and at 420 and 1500 m depth. An M = 2.8 earthquake that occurred 0.9 km away from the array at a depth of 5.3 km on 31 July 1986 generated rays traveling al...

S U M M A R Y A newMatched Filtering Algorithm (MFA) is proposed for detecting and analysing microseismic events recorded by downhole monitoring of hydraulic fracturing. This method requires a set ofwell-located template (‘parent’) events, which are obtained using conventionalmicroseismic processing and selected on the basis of high signal-to-noise (S/N) ratio and representative spatial distrib...

Methods of site response analysis require theoretical and empirical testing and validation before they can be used in seismic hazard assessment. Comparison of site amplification function (SAF) calculated using earthquake data recorded by seismic arrays with SAF obtained using analytical approaches represent the most important tests of reliability of those methods. The Treasure Island (TI) downh...