Protecting Parent-Well Production Using Far-Field Diverters in Unconventional Wells

Abstract

Abstract The impact of fracture driven interaction (FDI) is an increasing concern in mature developed unconventional plays in the US. In this study, parent well production performance after infill well stimulation is evaluated to understand the effectiveness of far-field diverter in mitigating FDI's. Studies to determine if FDI's result in a negative or positive impact, have concluded that it varies from basin-to-basin (Miller et al 2016). In this project, the purpose of pumping far-field diverter is to mitigate wellbore sanding and production loss in existing parent wells. The far-field diverter pill includes a blend of multimodal particles to bridge the fracture tip, preventing excessive fracture length and height growth. Fracture modeling with a unique particle transport model is typically used to design the far-field diverter pill impact on fracture geometry. The pill design and contingency designs are executed in the infill well stimulation job, right after the pad step, in the beginning of the pump schedule. Optimization of the far-field diverter can be complemented with real-time pressure monitoring or cross-well fiber strain data on the parent well. Over the years, far-field diverter has, in one form or the other, been used for various applications in stimulation design. However, since mid-2010's, far-field diverter has been used to address growing concerns of FDI's observed in most mature plays in the US. In this study, since 2018, far-field diverters have been pumped in several wells for the purpose of mitigating the negative impact of FDI's between parent and child wells. While these jobs were operational successes, the next crucial step was to evaluate and quantify the effectiveness of the far-field diverter in mitigating production loss in the parent wells. It is important to note that the operator whose wells utilized far-field diverters, had experienced negative impact of FDI's in their parent wells in the form of production loss and sand in the wellbore which required clean outs at a significant cost. In this study, production data was evaluated comparing pre-stimulation production before shut-in and post-stimulation production after the parent wells were brought back online. Overall, about 75% of the parent wells protected show positive uplift in oil production. And about 80% of the child wells show superior or comparable production decline after about a year of production when compared with offset parent wells It is evident that far-field diverters for fracture geometry control in child wells can be extremely helpful in mitigating negative impact of FDI's. In unconventional reservoirs, where infill (child) well drilling is prevalent, the impact of far-field diverter in controlling fracture geometry has the potential to be a value added FDI mitigation technology to mitigate wellbore sanding and subsequent clean outs as well as optimize production performance of both child and parent wells. The early part of the project resulted in ~$2.5million in savings in well cleanup costs. In addition, fracture diagnostics along with production data evaluation can be highly beneficial in understanding the role of production depletion, completion design and well spacing on fracture driven interaction.