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Modeling Unconventional Resources With Geostatistics and Basin Modeling Techniques; Characterizing Sweet-Spots Using Petrophysical, Mechanical, and Static Fluid Properties


Unconventional resource plays have become front-and-center in the exploration and development arena particularly in North America. Effective modeling tools for these resources are struggling to keep pace with exploitation principally due to the novelty of these resources. We simply have not yet established best modeling practices along with successful stimulation treatments. Currently, we are in a state of trial-and-error using immature research results to improve success in defining the physical characteristics of the ‘sweet spots’ and determining the appropriate methods to use to stimulate them. However, practical workflows for identifying sweet spots in these resources can be created using conventional geomodeling techniques with some modifications and innovations. Traditionally, reservoir geomodeling focused on describing static rock properties in the subsurface of a localized area. Such models could be stochastic or deterministic, but have no way to describe the means by which the reservoir arrived at its current state. Nor can they identify the condition of the static fluid or gas properties residing within. The state of fluid and gas properties (their level of maturity) is usually determined in a basin model which simulates through time a variety of conditions and variables such as sedimentation, burial, erosion, uplift, thermal condition, pressure calculations, and diagenesis prediction. In other words, the basin model simulates all the processes acting on rocks and fluids during the development of a sedimentary basin. These calculations are generally applied to entire basins or large portions of them. This paper demonstrates how to apply basin models at the reservoir scale, combining geostatistical reservoir modeling with thermal maturation and burial history to identify reservoir sweet spots in unconventional plays along with their static fluid and gas properties. The process is demonstrated for a portion of the Eagle Ford Shale.