Increase Exposed Bitumen Reserves by Optimizing Wellbore Placement in Oil Sands with Extra-Deep Azimuthal Resistivity LWD Service

This paper describes a novel approach in drilling production wells while implementing real-time mapping of the Bitumen-Water Contact (BWC) with extra-deep azimuthal resistivity (EDAR) logging while drilling (LWD) service, thereby resulting in an increase of exploited bitumen reserves by optimizing wellbore placement. Within the Athabasca Bitumen Reservoir, the EDAR LWD service confidently mapped the BWC within a range of 2-22 meters below the entire producer wellbore. It also provided an earlier warning of an approaching low resistivity boundary, which allowed the operator to optimize the wellbore placement using real-time proactive steering decisions. In contrast to the existing azimuthal resistivity tools, which have the limited depth of investigation, this approach significantly mitigated the risks of intersecting or giving an incomplete picture of BWC surface. The real-time interpretation of extra-deep azimuthal resistivity data provided better understanding of the lateral distribution of the McMurray Formation along the horizontal wellbore, lithologically varying from clean sand facies to mud-filled channel facies and inclined heterolithic stratification (IHS) facies. The fluid heterogeneity of the reservoir included partial reservoir charging, irregular BWC and lean zones, which compounded lithology complexity within the reservoir. In one of the case studies, 50 percent increase was achieved in actual exploited bitumen reserves in comparison to the projected exploited reserves if drilled per the planned trajectory. This new LWD approach was proven effective while drilling horizontal appraisal and producing wells in unconsolidated formations with high reservoir heterogeneity, it offered an opportunity to better understand the bitumen reservoir and ultimately led to increased production performance of Oil Sands projects.