deconvolution | Energy Glossary

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1. n. [Geophysics]

A step in seismic signal processing to recover high frequencies, attenuate multiples, equalize amplitudes, produce a zero-phase wavelet or for other purposes that generally affect the waveshape. Deconvolution, or inverse filtering, can improve seismic data that were adversely affected by filtering, or convolution that occurs naturally as seismic energy is filtered by the Earth. Deconvolution can also be performed on other types of data, such as gravity, magnetic or well log data.

See: autocorrelationbackscatterdeterministic deconvolutionfilterinverse filterprocessingresolutionsignature deconvolutionzero-phase

2. n. [Formation Evaluation]

With reference to induction logging, a method of removing shoulder-bed effects from an induction log. The term refers to early 6FF40 and deep induction logs in which the standard method of deconvolution was based on three measurements separated by 78 in. [198 cm] in depth. The three measurements were weighted by an amount calculated to reduce the effect of shoulder beds on the readings in a high-resistivity bed. Originally, the resistivity of the shoulder beds could be input, but in later usage this resistivity became standardized at 1 ohm-m. The deconvolution was not effective in high-contrast formations. In modern tools, the shoulder effect is corrected by using an inverse filter or an automatic inversion.

See: 6FF40bedinverse filtershoulder bed

3. n. [Well Testing]

A mathematical operation that uses downhole flow-rate measurements to transform bottomhole pressure measurements distorted by variable rates to an interpretable transient. Deconvolution also can use surface rates to transform wellhead pressures to an interpretable form. Deconvolution has the advantage over convolution that it does not assume a particular model for the pressure-transient response. However, the simplest form of deconvolution often gives a noisy result, and more complex approaches may be computing intensive.

See: convolutiontransient rate and pressure test analysis