Fracture hits significantly reduce production in parent well

In recent years, many operators have encountered well interference when fracturing laterals adjacent to existing productive parent wells at drill-to-hold lease sites. Reduced pressure from previously stimulated or depleted areas creates a path of least resistance for a nearby infill well stimulation, causing mild, severe, or complete production impairment of the parent well. Schlumberger investigated interwell interference on Eagle Ford parent wells and infill wells and its impact on production.

Integrate multiple data sources to accurately model and minimize risk

Schlumberger stimulation, reservoir, and geomechanics engineers developed an integrated workflow beginning with a geocellular model constructed using 3D seismic data, stratigraphic correlations from offset vertical pilot wells, and openhole well log data. The 3D seismic data were also used to characterize the spatial variability of natural fracture intensity and orientation to build the DFN model. A UFM unconventional fracture model was generated in the Kinetix reservoir-centric stimulation-to-production software to simulate the hydraulic fracture network created with each pumping schedule in the Eagle Ford Shale.

Initial production and depletion of the parent well were simulated with the INTERSECT high-resolution reservoir simulator, which included pressure-volume-temperature data, relative permeability, and pressure-dependent fracture conductivity.

The simulated 3D reservoir pressure field was imported into the VISAGE finite-element geomechanics simulator to determine the spatial and temporal evolution of magnitude and azimuth of the in situ stresses, which were then used as input to model fracture propagation for the infill well. A final simulation combining the parent and infill well completed the workflow.

Operators optimize development strategies to minimize risks

The ability to model pressure depletion and the associated new stress state with respect to the time between production of the parent well and fracturing of the infill well was an integral part of the overall basin production strategy. The complex interaction between stress reduction, stress anisotropy, and stress reorientation with the DFN determined if newly created fractures will propagate toward or deflect away from the parent well.

In recognition that the UFM model workflow enables a deeper understanding of how to rationalize complex drilling and completion operations, several Eagle Ford Shale operators have selected Schlumberger to model the complex fractures and interwell interference. The Kinetix software's stimulation design and modeling workflow has been used for subsequent development strategies, including optimization of infilling and refracturing programs, spacing of infill well laterals, and control of fracture propagation to minimize undesired fracture hits and other interferences.