Detailed geologic understanding of the Bakken/Three Forks petroleum system is made daunting by: the play's broad extent (~200,000 square miles across North Dakota and Montana); the types of data defining the play (depth, thickness, TOC, R0, etc.) and the sheer volume of data (>4000 horizontal wells). Predictive analytics are well suited for managing data overload and identifying key statistical relationships. In the context of this study, these workflows take the form of analytic interpretation and modeling to analyze thousands of well logs, remove redundant data, automatically classify lithofacies and interpret geologic tops, and use this data to characterize regional sweetspots.

An unsupervised hierarchical classification technique is used to identify the major facies of the Middle Bakken, the Upper and Lower Bakken source rocks and the multiple benches of the underlying Three Forks. These facies classification logs are more distinctive than any individual well log for identifying stratigraphic boundaries - supporting automated geologic top interpretation. With key geologic interfaces identified, depth and thickness maps are constructed and wellbore zones are defined, over which petrophysical properties are extracted and gridded.

A number of geological and geophysical measurements including depth, thickness, geochemistry, gravity and magnetics can be used to map regional " sweetspots". Analytic techniques are ideal for identifying and excluding spurious data, removing data redundancy and simultaneously comprehending multiple dimensions of data in order to highlight regional sweetspot trends. For the Middle Bakken formation, thermal maturity, depth and Middle Bakken thickness are key geologic attributes for analytically defining the core development areas and the abrupt production " line-of-death" at the eastern edge of the Parshall field.

The resulting sweetspot map correlates highly with well performance and highlights regions of no production, high water cut, marginal production and outstanding production. A production sweetspot map is valuable for acreage acquisition and divestiture, development prioritization and well planning. When coupled with well spacing considerations, a full development plan can be optimized to optimally place and space horizontal wells.

URTeC 1619602

This content is only available via PDF.
You can access this article if you purchase or spend a download.