Some Fracs Are More Equal Than Others: Expanding the Use of a Complexity & Conductivity Focused Frac Design in the Williston Basin

Abstract

A novel completion approach was developed in 2010 for Central Basin Bakken wells that focused on incorporating plug & perf technology with slickwater fluids and ceramics proppant in an uncemented liner. While these jobs can be very unforgiving from an execution perspective and are more expensive to complete, production from more than one hundred wells shows that this approach is superior in comparison to conventional ball-sleeve, gel and sand completions. We believe the improved production response for this completion approach benefits from (1) creating a more complex fracture geometry through the distributed plug-and-perf initiation points and the creation of widespread complexity through high-rate large-volume low-viscosity frac jobs; and (2) placement of higher conductivity, with smaller-size and stronger proppants to more effectively prop open complex fracture networks. Application of this design was initially limited to the Central Basin, but has recently been applied in other areas across the Williston Basin including both the poorer quality rock along the fringes of the basin as well as the naturally fractured and prolific rock on the Fort Berthold Reservation. In addition, other operators have conducted designs across the basin with a similar focus on conductivity and complexity, albeit achieved through alternate design strategies. This paper starts with a review of completion practices for the entire Williston Basin and how they compare to a complexity & conductivity focused design. We will present multi-variate analysis results to determine which geological or completion parameter has the most impact on production response, and what design parameter gives the best "bang for the buck" in an economic evaluation of these completion and fracture design changes.