Real Time Stratigraphy: Improving Placement of High Angle Wells using INPEFA Log Transform Correlation in Carbonates

We present a real time log processing workflow that allows confident placement of wells, especially in complex carbonate depositional sequences, by exploiting a wealth of stratigraphic information present in conventional logging data. The workflow is based on the spectral analysis of data logs that identifies a hierarchy of sedimentary cycles, controlled by orbitally forced climate change. The INPEFA Log Transform (INPEFA), which is the key process in this workflow, mathematically analyses composite waveforms consisting of various amplitudes, phases and frequencies. Geologically, INPEFA is able to predict lithofacies variability, stratigraphic discontinuities and genetic relationship of depositional sequences. Application of the INPEFA workflow to real time stratigraphy provides a framework to interpret stratigraphic sequences while drilling. The benefits of this workflow includes optimal well placement and drilling operations by using a simplified Bottom Hole Assembly (BHA) solution permitted by minimalised logging requirements. This enables operators to make fast decisions during geosteering, save costs on logging equipment and obtain a higher Dogleg Severity (DLS).