Global method for seismic-well tie based on real time synthetic model

Abstract

This paper presents an original global method which computes a real time synthetic model from seismic data, during the well-tie process. Based on a relative geological time model resulting from global seismic interpretation and on synthetic seismograms, this technique intends to give a comprehensive view of the seismic-well tie and completes the standard workflow. Instead of correlating the synthetic log with the nearest seismic traces only in the vicinity of the well trajectory, a synthetic model is computed in real time by propagating the synthetic seismogram into the geological model. Minimizing the relative errors between the real seismic data and the synthetic model automatically enables the determination of the optimum time shift value to apply to the current time-depth relationship. Moreover, as stretching and squeezing the synthetic log is still controversial, the method allows to check and understand the global consequences of local change in the time-depth relationship. Such a technique can be used on a single well or on multi-well analysis. In the latter case, reference tied wells are used as hard constraints for the synthetic model. The method highlights any mismatches or polarity change and therefore is more sensitive to well-to-seismic mistie. Applied to the North Sea K05 block dataset, this approach has clearly shown successful results in improving the well calibration in complex geological areas. Using more advanced kriging techniques, the method also opens the path for future applications where rock properties or velocity models would be compared.

Acoustic Impedance Inversions for Offshore CO2 Storage: South Georgia Embayment, United States

“…Therefore, seismic-well tie analysis has been conducted to compare well logs (measured in depth units), with seismic data (measured in time units), by creating a time-depth relationship using the sonic log and the check shots to improve and adapt the depth-time conversion. The correlation applied included 1) using key well tops to match peak-peak or trough-trough, 2) using bulk shift to tie synthetic to seismic or variable time shift to move and stretch two or more horizons, and 3) using the alignment points to make small adjustments between the synthetic and real seismic data (Cubizolle, et al, 2015; Figure 5). Build Initial Model and Inversion Analysis n more detail, the initial model of impedance is generated by using the P-wave impedance logs calculated from the sonic and density logs from the well log with a low-pass filter.…”

3D static reservoir modelling to evaluate petroleum potential of Goru C-Interval sands in Sawan Gas Field, Pakistan

“…Seismic sequence stratigraphy techniques aid in establishing the depositional setting of a particular formation for a basin while assisting the prediction of lithologies (Vail et al, 1987;Ahmed et al, 2004;Munir et al, 2011). Key lithologic horizons identified on seismic reflection data are correlated to well data either by generating synthetic seismograms, check shot surveys or by a vertical seismic profiling (Cubizolle et al, 2015;Ali and Farid, 2016;Wu and Caumon, 2017). Utilizing the results of studies from well data to predict and map reservoir properties over large areas can provide a guide for the reservoir modelling procedure (Ali et al, 2018(Ali et al, , 2019.…”

Establishing Time-Depth Relationships Constrained by Modes of the Reservoir Architecture

“…To date, researchers propose many approaches to improve the seismic well tie. Cubizolle et al employ a real-time synthetic model to determine the time shift value during the seismic well tie [10]. This method allows checking the global consequences of local change in the TDR.…”