SPE Permian Basin Chairman's Corner- February 2021

This month’s section meeting will be a Distinguished Lecturer presentation discussing mitigating production degradation due to frac hits in unconventional reservoirs. I thought it would be a good idea to discuss some other work done to investigate the same topic.

Endeavor published a couple studies at the Hydraulic Fracturing Technology Conference (HFTC) and the Unconventional Resources Technology Conference (URTEC). SPE 194349 details well-to-well communication between primary and infill wells in the Lower Spraberry and Wolfcamp benches. This was a “do-nothing” case where no primary-infill well protection was implemented and the study was focused on quantifying the communication using tracers and high resolution pressure gauges on horizontal and vertical wells. To mitigate this communication, SPE 199686 discusses pre-loading the first order and second order primary wells in an area that is geologically similar to the “do-nothing” case. The study concluded that fracture driven interactions were mitigated between primary and infill wells during the infill well frac’s and the infill well performed similarly to the primary well before it was pre-loaded. URTEC 3114 goes into greater detail on characterizing the fracture types during the primary and infill well frac’s. The idea is to generate as many shear fractures and minimize tensile fractures to maximize the fracture surface area, correlating to greater production. Pre-loading the primary well allowed the first-order infill well to generate the most amount of shear fractures (Figure 2) and the largest linear flow parameter (Acsqrtk, Figure 1).

Figure 1: Linear Flow Parameter Comparison to Primary.

Figure 2: Percent Tensile Fractures Observed

In Figure 1, P1B refers to the first order primary well and I-1B refers to the first order infill well. From the linear flow parameter comparisons, I-1B had the largest linear flow parameter and the least amount of tensile fractures observed shown in Figure 2. For more details of these studies, please peruse the aforementioned papers from HFTC and URTEC.

Additional papers to consider on primary-infill well protection are SPE-191712 and JPT’s “Fighting Water With Water: How Engineers Are Turning the Tides on Frac Hits. In the former paper, BHP published a multi-basin study on the usage of pre-loading the primary wells with water to limit asymmetrical fractures for the infill well. The paper also quantifies production differences between primary and infill wells due to continuously flowing the primary well during the infill well frac, shutting-in the primary well, and small preloads. Figure 3 displays these production differences in the Permian:

Figure 3: Permian Frac Hit Mitigation Effectiveness (SPE-191712)

According to the figure, pre-loads yield the most positive results compares to other methods.

In the JPT article, Abraxas uses active well defense to protect the primary and infill well during the infill well frac. Active well defense “relies on sporadic injections to reinforce the preloaded water.” Real-time pressure monitoring is critical in order to push back on potential asymmetrical fractures from the infill well.

Other SPE papers to review on this topic are stated in the references. We look forward to the section meeting and the discussion regarding mitigating production degradation due to fracture-driven interactions.

References:

Bommer, Peter A. Bayne, Marcus A. Active Well Defense in the Bakken: Case Study of a Ten-Well Frac Defense Project, McKenzie County, ND.2018. 2018/01/23. 10.2118/189860-MS

Bommer, Pete, Iriarte, Jessica, Bayne, Marc, Cline, Colby, Ramirez, Alberto, Van Domelen, Mary. Leveraging Cloud-Based Analytics in Active Well Defense Projects and Automated Pressure Response Analyses. 2020. 2020/02/04. 10.2118/199735-MS

Bommer, Peter.Bayne, Marc. Mayerhofer, Michael. Machovoe, Mike. Staron, Maciej. Re-Designing from Scratch and Defending Offset Wells: Case Study of a Six-Well Bakken Zipper Project, McKenzie County, ND. 2017. 2017/01/24. 10.2118/184851-MS

 Jacobs, Trent.Fighting Water With Water: How Engineers are Turning the Tides on Frac Hits. 2018. 2018/12/01. 10.2118/1218-0034-JPT. Journal of Petroleum Technology

Scherz, Yvonne, Pradhan, Yogashri, Rainbolt, Michael, Johnston, Thomas. Evaluating Primary-Infill Well Performance After Frac Mitigation Using Fracture-Type Diagnostics in the Midland Basin Wolfcamp Shale. 2020. 2020/07/20. 10.15530/urtec-2020-3114

Scherz, R. Yvonne, Rainbolt, Michael F., Pradhan, Yogashri ,Tian, Wei. Evaluating the Impact of Frac Communication Between Parent, Child, and Vertical Wells in the Midland Basin Lower Spraberry and Wolfcamp Reservoirs. 2019. 2019/02/05

Scherz, P. E., R. Yvonne, Pradhan, P. E., Yogashri, Rainbolt, P. E., Michael F. Mitigation for Fracture Driven Interaction: A Midland Basin Case Study. 2020. 2020/02/04. 10.2118/199686-MS

Whitfield, Tom, Watkins, M. Hunter, Dickinson, L. James, Pre-Loads: Successful Mitigation of Damaging Frac Hits in the Eagle Ford. 2018. 2018/09/24. 10.2118/191712-MS