Among the numerous shale formations worldwide, Argentina's Vaca Muerta unconventional play stands out as one of the most promising shale oil and gas emerging plays outside North America. In unconventional reservoirs, the commercial success of the play is associated with the integration of multiple disciplines, the comprehension of the area, and the optimization of workflows and processes. In YPF, geologists, geophysicists, petrophysicists and engineers worked collaborative to consolidate a data repository with the purpose of building robust models, to improve the existent workflows and to generate a representative image of the subsurface.
The aim of this project was to generate an integrated geocellular static model that will be used as input for geomechanical hydraulic fracturing and dynamic simulations of horizontal wells in the Quintuco - Vaca Muerta depositional system. In the present study a semi-regional geocellular model was created incorporating 3D seismic data, seismic attributes, 22 vertical wells with petrophysical and geomechanical data, 3 vertical cores, and 5 horizontal image logs. Subsequently, a single pad model was cropped in an area that included 3 horizontal wells landed at 3 different zones and microseismic. A Discrete Fracture Network (DFN) model was built based on mechanical stratigraphy, fracture analysis, and constrained by the Stimulated Reservoir Volume obtained from filtered microseismic attributes. DFN outputs were used as inputs for the hydraulic fracture simulator. Finally, the fracture properties for dynamic simulation were upscaled using the ODA's method.
This study provided the opportunity to improve the property distribution that will impact the simulation results and will permit us to obtain better scenarios for well spacing optimization and performance prediction. Likewise, integrated large-scale models do not only allow us to preserve the geological trends but also will allow us to crop multiple single pads for systematic simulation of different pilot zones.
The Vaca Muerta play is considered one of the most prolific unconventional resources in the world. Currently, it is identified as the biggest shale play outside North America and makes Argentina the third country, after the United States, and Canada, to reach commercial development. Vaca Muerta has been compared in composition to the Eagle Ford in terms of depth, pressure, and mineral composition, according to the U.S. Energy Information Administration (EIA) (U.S. Energy Information Administration, 2013). However, Vaca Muerta deposit alone is twice as large as Eagle Ford. As reporting by EIA, the Vaca Muerta formation contains 16.2 Bbbl of tight oil (shale oil) and 308 Tcf of shale gas (U.S. Energy Information Administration and Advance Resource International Inc., 2015).