Predicting Unconventional Well Performance Using Shale Capacity - A Bakken Example

For unconventional fields, hydraulic stimulation is affected by different geologic drivers than conventional fields. These unconventional geologic drivers are Natural Fracture Densities, Brittleness, Porosity, and Total Organic Carbon. Combined, these four geologic drivers make Shale Capacity. Shale Capacity has been shown to correlate with well production.

In this Bakken case study, 3D seismic, well logs, and production information are available. 3D seismic is enhanced through a broadband spectral inversion. This enhanced seismic is used for calculating curvature, spectral attributes, post-stack inversions, and pre-stack inversions.

A Neural Network is used to rank the many seismic attributes in their ability to capture the petrophysical property variations of the well logs. This includes Natural Fracture Density, Porosity, and TOC – the geologic drivers of Shale Capacity. The Relative Intercepted Shale Capacity (RISC) equation measures the proportion of a wellbore that intercepts good Shale Capacity. Using seven wells, the relationship between RISC and 90-Days Initial Production is derived. The well production is predicted for wells not used in the derivation. Shale Capacity and RISC are used to derive a relationship between reservoir properties and well performance in unconventional reservoirs.