High Resolution Diffraction Imaging of Natural Fracture Zones in Unconventional Shale Reservoirs for Well Placement Optimization

Accounting for the geologic conditions in unconventional shales is an important factor in an optimization problem. Placing the wells too close wastes drilling money. Placing the wells too far leaves resources in the ground. Given the fact that a well in unconventional shales may cost $12-20 million, optimizing the well placement of hundreds of wells in a field becomes a very large cost savings and environmental protection technology. Using an optimal number of wells decreases the drilling cost while maximizing production, and decreases the environmental impact of developing the field by using less water, using less sand and chemicals pumped in the well and disturbing less the local communities. The development team at Z-Terra researched and identified in Phase I a new approach to image with super-resolution small scale faults, reflector unconformities, in general any small scattering objects, by using Diffraction Imaging as a complement to the structural images produced by reflection imaging. By identifying the areas with increased natural fracture density, the reservoir engineers can design an optimal well placement program that targets the sweet spots, areas with increased production, and minimizes the total number of wells used for a prospective area. In the Phase I project we developed Diffraction Imaging prototype software designed to image with super-resolution the small scale fractures in shale and carbonate reservoirs. Areas of increased natural fracture density are associated with higher production wells. The Phase I work accomplished the primary goal of examining the feasibility of imaging small scale fractures in shale reservoirs and improving the Diffraction Imaging technology. In the Phase II project we will research and demonstrate the correlation of the areas with high fracture density in reservoirs with increased oil and gas production, and build the commercial software analytics tools that allow the reservoir engineers to integrate the imaging tools with the reservoir optimization and well planning tools. Several new applications of the basic Diffraction Imaging principles also need to be developed, tools for analyzing and visualizing azimuthal variations of the diffraction amplitudes that in turn reveal information about the fracture and stress distribution in a reservoir, better visualization and post-processing of specularity gathers. Commercial Application and Other Benefits High resolution imaging of the small scale fractures in shale reservoirs like Eagle Ford, Bakken, Niobrara, Utica and Woodbine, and the identification of reservoir areas with high natural fracturing (1) reduces the field development cost, (2) improves the production and recovery efficiency by delineating the areas associated with increased oil and gas production in unconventional shale reservoirs, (3) decreases the environmental impact of developing the field by using fewer wells to optimally produce the reservoir, using less water, using less sand and chemicals pumped in the well and disturbing less the local communities, and (4) increases the amount of national oil and gas reserves that can be produced economically.