A Multi Well Case Study of Near Wellbore Fracture System Characterization Through Controlled Acoustic Pulsing and Tracer Diagnostics to Output Fracture Geometry, Optimize the Completion Approach and Understand Well to Well Communication
Authors: Khan Muhammad , Grubac Gabrijel , Christian Jason , Jayakumar Swathika , Ramos Claudio 
Published: September 2022

Abstract
A Bakken operator utilized real-time acoustic-based measurements of the fracture system to develop a better understanding of the near-wellbore regime and consequently optimize the completion design. The scope of this paper entails a seven-well project completed in the Middle Bakken. The paper discusses diverter application across the laterals, and the measured effect on the fracture system impedance across different types and volumes of diverter. Post-stimulation diagnostics (radioactive tracers and chemical tracers) along with production data are incorporated into the analysis for an enhanced understanding of the stimulation effectiveness. The workflow for continuous monitoring starts with establishing baseline measurements on the initial stimulation stages. A comprehensive understanding of the fracture system is given on a per stage basis quantifying near-wellbore connectivity and measuring fracture dimensions. Once a satisfactory baseline has been established, the process of adjusting the completion design can be initiated, if and as necessary. The progressive learnings are applied to maintain near-wellbore stimulation uniformity, enhance diverter effectiveness and ultimately positively impact well production. The project encompassed seven wells in Dunn Co, ND in the Middle Bakken formation. The south side of the pad had 3 wells landed in a depleted area due to offset producing wells whereas the north side had 4 wells landed in adjacency to one producing well. The results showed a relationship between depletion and the measured near-wellbore connectivity values. Operator elected to use far-field diverting material to restrict fracture propagation and, if possible, avoid negative pressure driven interactions with the offset producing wells. After exceeding a certain threshold of the far-field diverter, near-wellbore connectivity was restored, observed also through a reduction in the offset pressure activity of the production wells. This real-time workflow allowed the operator to accelerate the learning curve while optimizing the diverter strategy. The post-stimulation radioactive and chemical tracer data were coupled with the acoustic-based near-wellbore connectivity measurements to help better understand overall stimulation effectiveness and plausible future improvements to stimulation design. The continuous monitoring workflow presented in this paper provided a scalable, cost-efficient approach to monitor in real-time stimulation effectiveness and help mitigate cases of under-stimulation when such are identified. In this case study, the ability to evaluate diverter application and understand the effect of rate/proppant intensity per perforation on establishing sufficient near-field connectivity provide significant potential for the real-time optimization of completion and production operations.