Maximum array length for given apparent velocity

From SEG Wiki
Jump to navigation Jump to search


Reflections in the zone of interest have apparent velocities around 6300 m/s, whereas the velocity just below a uniform LVL is 2100 m/s. If we wish to avoid severe attenuation below 80 Hz when using an array, what is the maximum inline array length?


The LVL is discussed in problem 4.16. Apparent velocity is defined in problem 4.2d. See problem 8.6 for a discussion of array response. Note that the array length, , is larger than the distance between the first and last geophones, .


To avoid deterioration, the response curve for the array length , where n is the number of geophones and the geophone interval, must not extend beyond the first null (see Figure 8.6b). Equation (8.6b) shows that the first null occurs when or , where is the phase difference between adjacent geophones. Problem 8.6a gives , so


where apparent velocity and apparent wavelength. Thus.

The geophone interval must not exceed .

Continue reading

Previous section Next section
Attenuation of air waves Response of a linear array
Previous chapter Next chapter
Seismic equipment Data processing

Table of Contents (book)

Also in this chapter

External links

find literature about
Maximum array length for given apparent velocity
SEG button search.png Datapages button.png GeoScienceWorld button.png OnePetro button.png Schlumberger button.png Google button.png AGI button.png