Dynamic Depth Alignment Between Well Logs for Enhanced Petrophysical and Rock Physics Interpretation

Two well logs from the same section of a well often have an unknown depth shift between each other. If the well logs are corrected for this depth shift, the correlation be- tween the logs will increase. We formulate an optimi- sation problem that maximises the correlation between the logs, while maintaining a physically reasonable depth shift. We implement a simple solver for this optimization problem and test it on real well logs from the Norwe- gian continental shelf. We demonstrate that changing the tradeoff between the correlation term and the smooth- ness term in our cost function also changes the tradeoff between correlation and smoothness in the resulting es- timated depth-shift. The automatically estimated depth shifts were confirmed by expert opinion to be similar to the depth shift that would have been estimated by an ex- pert on data from 12 real wells, illustrated in Appendix A.