High-node-count, high-frequency-downhole-offset microseismic mapping was employed in conjunction with surface microdeformation (tilt) monitoring over an exploratory horizontal completion located in an oil-window Eagle Ford horizon where the magnitude of the maximum principle horizontal stress was close or equal to the overburden stress. The two far-field mapping technologies were merged in an effort to take advantage of the relative strengths of each, and to provide independent verification of various deliverables. A new deterministic calculation regime for the estimation of Stimulated Reservoir Area (SRA) and Stimulated Reservoir Volume (SRV) was implemented and compared to more conventional calculations of SRA performed with microseismic event positioning. A number of interpretive conclusions were drawn for each technology. It became apparent that with respect to the microseismic mapping effort, microseismicity alone may not always be sufficient to fully describe far-field fracture placement, geometry and orientation, and multi-planar joint inflation in shallow mapping scenarios. The surface microdeformation diagnostics suggested that additional confidence in the combined interpretation was possible. Herein the overall mapping effort in terms of both technologies, and the various stress regimes are characterized in terms of their relationships to the induced fracturing orientation and the interaction with pre-stressed, naturally occurring geological features. It is shown that a geomechanical inversion based on surface microdeformation is capable of resolving the spatial distribution, orientations, and the principle fracture components of the complex network. The added knowledge of localized induced fracture distribution, orientation, geometry, and feature count per unit of SRA can be useful (and even fiscally material) in the shallower portions of the oil-window Eagle Ford.
The subject well is located in the northwestern portion of the Eagle Ford play in south Texas, and was stimulated for oil and gas production using 16 hydraulic fracture treatment stages along 1,524 m of the horizontal lateral.
