Synthetic seismogram (Geophysics)

in science •  7 years ago  (edited)

Good evening steemit community.

Today I will tell you a little about synthetic seismograms.

A synthetic seismogram is understood as the result of one of the many forms of direct modeling to predict Earth's seismic response.

generacion de coeficiente de reflex.PNG

A narrower definition used by seismic interpreters is that a synthetic seismogram, usually called only synthetic, is a direct one-dimensional model of the acoustic energy that propagates through the Earth's layers. The synthetic seismogram is generated by the convolution of the reflectivity derived from the digitized acoustic and density registers, deriving the wavelet from the seismic data.

sismograma sinteticoo.PNG

Basically, a synthetic seismogram consists in the reconstruction of a seismic trace in the direction of the well, by means of the convolutional model and these are generated in order to relate the well data (which are recorded in the depth domain) with the seismic data ( recorded in time domain), in order to establish relationships between the different intervals of interest with the responses of seismic events.

Next, each of the parameters is defined to generate the synthetic seismogram:

  1. The seismic wave: a one-dimensional pulse is defined, which represents the shape of the reflection in the time domain of a reflector in the case of normal incidence.

  2. Reflection coefficient: is the graphic representation of a series of lithological layers. When a wave travels through a formation over another with higher acoustic impedance, it produces a positive reflection coefficient, while a formation over another with lower acoustic impedance generates a negative reflection coefficient.

  3. Convolution: is a mathematical operator that transforms two functions f and g into a third function that in a certain sense represents the magnitude in which f is superimposed and a translated and inverted version of g. In this case, the well data added to the reflection coefficients is convolved with the wavelet and generates a synthetic seismogram.

  4. Seismic impedance: is the product of density by seismic velocity, which varies between different rock layers and is usually indicated by the symbol Z. The difference in acoustic impedance between the rock layers affects the reflection coefficient.

sismograma sinteticoooo.PNG

The result of the convolution of these parameters is the generation of the synthetic seismogram which is in turn the physical representation of the subsoil

Well dear friends of this community, this has been all for today. I hope it is to your liking and your interest we see you in another opportunity :)

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