Publications

Seismic time to depth conversion is an important part of seismic interpretation work flow. This research was conducted to determine the best method of depth conversion as a tool for horizon prediction in a proposed well-site “KYT” well. In this research, the seismic time to depth conversion process was divided into nine different methods clustered into two groups of methods. The difference in those methods lies on the variation of velocity model building. The velocity model building was built from two velocity sources: checkshot velocity and seismic stacking velocity. Those two velocity sources were processed using a geostatistical approach to obtain the velocity model. As the process results in several numbers of timeconverted data, it needs to be uncertainty analyzed to obtain the best method and the best depth values. The uncertainty analysis in this method was applied to four horizon Sand reservoirs (Top ARC, Top ASH, Base ASH, and Top TALC) by using the percentile classification approach, where the nine time-converted data were classified into three percentiles: 10th percentile (P10) or Low Case, the 50th percentile (P50) or Base Case, and the 90th percentile (P90) or High Case. The results of the process show that the time-depth conversion method using the velocity model of the seismic stacking velocity with moving average interpolation shows the best result. This is justified by the minimum value of the horizon depth error to the same horizon in the well marker data. This uncertainty analysis is an effective and relatively inexpensive tool to guide and to predict horizon depth in a drilling process to minimize the error.