An Integrated Study of Core and Well Log Data to Characterize Oil Sands in a Research Wellbore at Kearl Mine

Abstract

Coring and core analysis play an important role in subsurface characterization in oil sands mines in northeastern Alberta. The oil sands are composed of Cretaceous-aged fluvial channels and overbank material that display complex vertical and lateral variability. Core hole drilling at spacing of 100-200 m is routine in oil sands mining operations to adequately characterize the subsurface for safe and economic operations. Whole core samples are analysed for the purpose of defining a robust stratigraphic framework and for obtaining key mining parameters such as bitumen mass fraction, particle-size distribution, clay content, and geotechnical data. A research corehole was drilled at Imperial's Kearl oil sands mine to acquire core and well log data that would allow for a detailed investigation of oil sand petrophysical properties and to evaluate the value and applicability of well log data in subsurface mapping and modeling. One hundred and ten metres of core were recovered from the one hundred and fifteen metre corehole and a comprehensive suite of wireline logs were run from surface to TD that included gamma ray, density, neutron, dipole sonic, lateral and induction resistivity, NMR, dielectric, and image logs. Logging tools from two major logging vendors were utilized and core analyses were performed in two commercial labs. Over two hundred core plugs were sampled for routine core analysis. Duplicate plugs were measured for Archie electrical properties, clay properties, and XRD/XRF mineralogy. Laboratory NMR and dielectric measurements were made using a selected number of samples. Petrophysical evaluation results show excellent agreement in rock and fluid properties between core and log measurements. Core analysis data for conventional core plugs and homogenized samples from two labs are in good agreement. Comparison of water saturations between Dean-Stark and the dielectric log is an excellent match. Dielectric permittivity and constants from core measurements are in close agreement with log data at high frequency. NMR log signatures show sensitivity to bitumen with viscosity as high as 106 cp. In conclusion, this study demonstrated that many of the critical attributes in oil sands mining operations can be obtained from a carefully designed logging program with properly calibrated logging tools. This result has led to the building of predictive petrophysical models at the Kearl oil sands mine and the replacement of some cores with wireline logs (Ye, 2016).

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016