Look Ahead of the Bit While Drilling: Potential Impacts and Challenges in the McMurray Formation

The oil and gas industry, operating and service companies, and academia are actively looking for ways to see ahead of the drillbit while drilling to reduce the risks and costs of the operation and improve the well-placement process. Optimal drilling in the challenging and highly heterogeneous reservoirs, where geological interpretations overlook the high-frequency variations in the rock properties, requires reliable subsurface information from around and ahead of the drillbit. To provide this, we have developed a seismic-while-drilling imaging algorithm based on signal processing, drillstring modeling, and pre-stack wave-equation migration. To extend the visibility ahead-of-the-bit, we use the drillbit as a seismic source and image the changes in acoustic properties of rocks both around and ahead of the drillbit. The common practice is to build a reverse vertical seismic profile (R-VSP) gathers. Here, we use a blind deconvolution algorithm to estimate the drillbit source signature from the data directly. Alternatively, we can estimate such a signature through drillstring modeling and top-drive measurements (i.e., force and velocity). The drillstring dynamics is modeled by using Riemann's invariants and a backstepping approach. Next, we input the estimated source signature to the pre-stack wave-equation depth imaging workflow. Our simulations show that providing drillbit source signature to the pre-stack wave equation depth migration consistently delivers reliable subsurface images around and ahead of the drillbit. The output of our workflow is a high-resolution subsurface image that provides vital information in oil sands reservoirs for placement of steam assisted gravity drainage (SAGD) well pairs. Compared to conventional practices, the proposed methodology images around and ahead of the drillbit enabling interactive decision making and optimal well-placement. The key feature of the presented methodology is that instead of cross-correlating the seismic-while-drilling data with the pilot trace and building RVSP gathers, we use the estimated drillbit source signature and deliver high-resolution pre-stack depth migrated images. Through numerical modeling, we tested the potential impacts, validity, and challenges of the proposed methodology in drilling horizontal wells in SAGD settings with an emphasis on the McMurray Formation. We further compared the results with the conventional drilling practice. In contrast to existing tools that have limited depth of penetration, interpreting seismic-while-drilling data in real-time