Mitigation for Fracture Driven Interaction: A Midland Basin Case Study
Authors: Scherz, P. E. R. Yvonne , Pradhan, P. E. Yogashri , Rainbolt, P. E. Michael F. 
Published: January 2020

Frac Driven Interactions (FDI) have gained much attention, but like many past challenges in our industry, a solution is not far behind. The ability and willingness of operators to share information is at the core of advancing this solution. Not content to just shut-in our wells and "hope for the best" during nearby frac ops, we decided to pro-actively learn about FDIs and to apply the learnings to frac defense. Frac defense not only protects the primary well, it also helps to prevent asymmetrical fractures in the infill well. We provide methodology used to design and implement FDI defense. Additionally, we also show how we analyzed the results of the FDI defense to determine its success.

In 2018, we had an opportunity to learn about FDI and documented those interactions, along with the analysis, in SPE 194349-MS. The original study was initiated to understand FDI and to ultimately determine appropriate mitigation. In this case study, we used the findings from the initial study to select suitable mitigation: pre-loading the primary well with water prior to offset fraccing operations. The study location is one that had previously experienced FDI from offset development wells. The primary wells had recovered quickly from the past FDI but due to an additional year of depletion, our research showed that recovery would probably be longer.

The workflow covers well candidate selection, necessary personnel and equipment on location, and the risk analysis of the overall project. To monitor the effectiveness of mitigation after pre-loading, the team placed wellhead pressure sensors on pre-loaded primary wells, and primary wells in the adjacent pad. Sensors were installed on select vertical wells perforated through the target zones. In addition, wirelessy connected, high-pressure sensors were deployed on actively fraccing wells. All sensors were time-synced and monitored in real-time. Pressure results indicated that mitigation using the water pre-load method dampened FDIs. A successful application would manifest in pressure dampening and a reduction of recovery time. At the time of this writing, flowback operations are ongoing and one primary well recovered to pre-frac rates within one week. We anticipate a corresponding reduction of recovery time in the other wells. Most importantly, the infill well immediately offset from the primary is performing as good or better than the other infills in the same interval.

This paper presents methods ad processes that offer a potential solution to identify candidates for fracture mitigation, and optimize project economics in a full section, multi-bench development. A novel aspect to the data is that all wells were wirelessly connected to the internet, time-synced with the atomic clock, and monitored in real-time. Time-synched pressure indicators immediately reveal the earliest signs of well-to-well communication across the entire field of active and passive wells. Pressure readings are reflective of FDIs allowing the operator to monitor, and proactively apply mitigation techniques in real-time. This process is known as "active well defense." However, due to certain limitations, we deployed a "passive well defense" where we injected water into the primary wells prior to frac operations.