Unconventional reservoirs have gained prominence in recent years, yet well performance variability is not fully understood. The advent of horizontal drilling in conjunction with the ability to complete with multiple horizontal fracture stages has made production from these unconventional reservoirs economically possible. In order to improve and optimize the well performance, there is a need for collaborative effort from all disciplines including land, geology, geophysics, drilling, completions, production, and reservoir engineering. This collaboration is critical, especially in a challenged pricing environment, since every dollar spent should be effective. Cipolla (2011) has described the need for integration in detail in his publication.
In this paper, we describe in detail the collaborative work that was performed in the Cana Woodford play. Cana Woodford is an unconventional shale reservoir located in central Oklahoma. The fluid system is similar to Eagle Ford as it varies across the play drastically posing a necessity for integrated and collaborative effort to characterize the play. We adopted integration from seismic to simulation approach. The paper will elaborate on incorporating seismic data, petrophysical analysis, and geology to build a static reservoir model. The approach helped us in creating an accurate earth model with multiple facies calibrated to core data. Good understanding of facies model in tandem with geomechanical data is critical to utilize in the fracture model to understand fracture geometry. Fracture modeling results were then tied with dynamic reservoir modeling. This paper will elucidate well performance with varying completion design and the impact on overall performance, economics, and well spacing.
Geologic Setting of Cana Woodford
Deposited during late Devonian time, the Woodford formation is a prolific source mudrock in the Anadarko Basin of Oklahoma. Anoxic conditions prevailed during much of this time within this marine basin. Coastal upwelling, and other nutrient-supply mechanisms, helped generate an abundance of organic matter, which then settled onto the seafloor under relatively quiet conditions. This reducing environment allowed for the retention of organic matter in quantity and quality sufficient to later charge numerous reservoirs throughout much of the basin. Figure 1 shows a paleogeographic reconstruction of late Devonian North America around the time of Woodford deposition, with an accompanying global sea level curve for reference.
