Seismic techniques

Determining concrete thickness and characterising internal defects using seismic techniques... 

Technological advances, particularly 3-D seismic techniques and deepwater drilling technology, have... 

Seismic techniques, the reflection and refraction of sound or shock waves propagated through the earth, are also used to reveal details of the structure and interrelationship of various layers in the subsurface. The shock or sound waves record densities in the earth s surface that may indicate an oil or gas reservoir. Explosive charges or vibration devices are used to impart the required shock wave. 

However, as indicated by Kleinberg (2006) there is the need for a much better prospecting tool than the BSR, due to reliability issues. First, very little gas is required to produce a strong seismic reflector (Domenico, 1977). Second, an apparently continuous reflector does not imply a continuous gas-saturated zone. It is now well established by high resolution seismic techniques that BSRs that appear continuous in conventional marine seismic can actually be because of discontinuous patches of gas (Wood et al., 2002 and Dai et al., 2004). As a final example, the recent drilling of a BSR off the west coast of India failed because the BSR was caused by a carbonate deposit, rather than hydrates (Collett, T Personal Communication, November 6, 2006). 

A variety of seismic techniques have been used to study the upper mantle beneath the Western Superior Province. Each technique has its own advantages and disadvantages, but often one technique compensates for another s deficiency. For example, SKS-splitting analysis has poor vertical resolution but good lateral resolution, whereas surface-wave studies have poor lateral resolution but better vertical resolution. 

Addessi D., Ciampi V. (2001), Ongoing studies for the application of innovative anti-seismic techniques to chemical plant components in Italy, 7th International Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control of Vibrations of Structures, Assisi. 

Marine geophysical survey techniques can usually be used to locate such services. Sonar or multi-beam bathymetric surveys can map pipelines lying on the seabed. A magnetometer survey can be utilised to determine the position of buried steel pipelines. If a depth of burial is required, or if the pipeline is constructed of non ferrous material then a seismic technique using a pinger or boomer sound source will be required. 

In addition to porosity (for example Wyllie s equation), modem seismic techniques offer possibilities for ... 

To derive a reservoir geological model various methods and techniques are employed mainly the analysis of core material, wireline logs, high resolution seismic and outcrop studies. These data gathering techniques are further discussed in Sections 5.3 and 2.2. 

The common civil engineering seismic testing techniques work on the principles of ultrasonic through transmission (UPV), transient stress wave propagation and reflection (Impact Echo), Ultrasonic Pulse Echo (UPE) and Spectral Analysis of Surface Waves (SASW). 

Cross-section of seismic refrac on measuring technique (Zhody, 1974). 

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