Structural Interpretation

Prepared By:Nikhil G Barshettiwar(Petroleum Engineer)

Well Ties

- Synthetic seismogram- Vertical seismic profile (VSP) tie to seismic data

Synthetic seismogram-Use density and sonic logs. Density log gives density of formation and Sonic log use indirectly to calculate velocity. Product of density and velocity is known as ‘Acoustic Impedance’. - Acoustic Impedance log (AIL)show fine details of thin interbeds with different lithologies.-Once AIL is prepared, next step is to convert the log as function of two-way travel time. - The resulting acoustic impedance curve then use to calculate refection coefficients at each interface between contrasting velocities. -A wavelet is chosen that has frequency response and band width similar to that of nearby seismic data. The synthetic wavelet is convolved with the reflection series for the entire well survey and generates seismic trace.

Reflection coefficientR = (An+1-An)/(An+1+An)

Where An+1 & An are acoustic impedance of above and below the interface.

Convolution Model

T(t)=Ro(t)*w(t)+n(t)Where,T(t) = seismic traceRo(t) = Reflection coefficient seriesw(t) = waveletn(t) = Noise