TraceSeis evaluates the feasibility of estimating reservoir/geomechanical properties. It uses well-calibrated seismic data. The proposed workflow consists of four sequential stages.
Stage 1 – Rock physics analysis with SeisRP – Using well log data, TraceSeis estimates, at well-log and seismic-resolution, rock properties and seismic attributes for different reservoir conditions (porosity, lithology and pore fluids). In this stage, it is determined whether the physical properties of rocks allow the estimation of the reservoir properties of interest.
Stage 2 – Seismic data fitness evaluation and conditioning – Quantitative estimation of reservoir properties requires that pre-stack seismic data faithfully represent the offset dependent reflectivity of the subsurface. TraceSeis conditions the data to meet this requirement as close as data conditions allow. Processes to apply as required include: Calibration of amplitude variation with offset using as reference the pre-stack synthetic seismograms generated in Stage 1; attenuation of residual multiples; residual alignment of events across offset; random noise attenuation; and wavelet’s phase and amplitude equalization across offset.
Stage 3 – Seismic attributes’ computation – The attributes (reflectivities or relative properties) computed in this stage are those determined as optimum in Stage 1.
Stage 4 – Computation of reservoir/geomechanic properties – These are estimated through linear combinations of the seismic attributes computed in Stage 3. The coefficients of the linear fit are computed with SeisCar using well and synthetic data before doing the same with the real seismic. The properties output from this stage provide the basis for quantitative interpretation since their magnitudes approximate those of the reservoir/geomechanic property as measured by well-logs.