Integration of Thermal Core Profiling and Scratch Testing for the Study of Unconventional Reservoirs

Core analysis provides the essential information necessary for the characterization and development of hydrocarbon reservoirs. High core-scale heterogeneity and anisotropy, natural in unconventional reservoirs, complicate reservoir characterization and dictate the sampling methodology used. Continuous high-resolution thermal measurements with an optical scanner and scratcher along the core column can yield benefits in a sampling strategy. This article describes some features of the suggested integration of non-destructive thermal profiling with partially destructive scratch testing applied for the study of rocks from the Bazhenov Formation (West Siberia, Russia). The spatial variation in the unconfined compressive strength and thermal conductivity components parallel and perpendicular to bedding for more than 1000 samples are demonstrated and discussed on core and log scales. The relationships between these properties are established for different rock types composing the formation. The joint analysis allows specialists to correctly define multiscale heterogeneities and facies that would be difficult or impossible to observe with logging data analysis or geological description alone. The established relationships make it possible to partially replace the semi-destructive scratch test with non-destructive optical scanning, providing UCS estimation. One more important outcome of the present work is the lessons learned regarding how to organize future works. The integration of thermal core profiling and scratch testing data looks promising for unconventional reservoir characterization

Advanced Determination of Heat Flow Density on an Example of a West Russian Oil Field

Reliable geothermal data are required for basin and petroleum system modeling. The essential shortcomings of the methods and results of previous geothermal investigations lead to a necessity to reappraise the data on the thermal properties and heat flow. A new, advanced experimental basis was used to provide reliable data on vertical variations in the thermal properties of formation and heat flow for the area surrounding a prospecting borehole drilled through an unconventional hydrocarbon reservoir of the Domanik Formation in the Orenburg region (Russia). Temperature logging was conducted 12.5 months after well drilling. The thermal properties of the rocks were measured with continuous thermal core profiling on all 1699 recovered core samples. Within non-cored intervals, the thermal conductivity of the rocks was determined from well-logging data. The influence of core aging, multiscale heterogeneity and anisotropy, in situ pressure and temperature on the thermal properties of rock was accounted for. The terrestrial heat flow was determined to be 72.6 ± 2.2 mW·m−2—~114% larger than the published average data for the studied area. The experiment presents the first experience of supporting basin modeling in unconventional plays with advanced experimental geothermal investigations