Sequential Plugging Fluid Modeling for Lost-Circulation in Fractured Formations

Summary This paper investigates the application of type-curves for mud loss incidents within a natural fracture. The established solution mimics and predicts drilling mud loss in subsurface formations with conductive natural fractures. Mud loss during drilling is a complex and costly issue that disrupts operations and increases non-productive time. The goal of this study is to develop a transient solution tool that leverages mud type-curves during operational parametric variations to model multi-stage sequential injection of lost circulation material (LCM). This curve will provide key parameters such as transient shift mud loss volume, transient shift mud loss duration. The study integrates a semi-analytical approach to model mud loss using non-Newtonian fluid model, i.e. the Herschel-Bulkley fluid model, which accounts for shear-thinning behavior. A Cauchy equation of motion has been used to establish a tool that takes input parameters, such as yield stress, consistency factor, flow behavior index, wellbore size, bottom-hole pressure, and hydraulic fracture aperture, to generate a shift-trend solution. In current literature, the approach typically utilizes an analytical solution with constant parameters such as the fluid and formation properties, yet these properties may change over time. To address this challenge, we introduce a novel concept of shift-trend solution caused by variational parameters during drilling operations to measure and predict mud loss dynamics. The model was established and validated using field data to ensure accuracy and adaptability. The developed shift-trend model demonstrated high accuracy in predicting the dynamic trend with dynamic mud loss volume, maximum loss duration, and equivalent hydraulic fracture aperture under a different range of conditions. It effectively captured the complex, nonlinear relationships governing mud loss behavior in naturally fractured formations. The shift-trend solution successfully integrated Cauchy equation of motion, yielding predictions that are closely aligned with field observations. This streamlined approach reduces computational demands while maintaining reliability, offering practical solutions for real-time decision-making in lost circulation scenarios. This study introduces a novel shift-trend solution framework for modeling and mitigating mud loss in naturally fractured formations. By combining non-Newtonian fluid model with Cauchy equation of motion, the proposed tool enhances the predictive capabilities of traditional methods and provides actionable insights for managing lost circulation via additives to stop/mitigate lost circulation severity, such as lost-circulation materials. The approach is adaptable to diverse scenarios, making it an accurate and efficient solution for addressing one of the oil and gas industry’s most persistent challenges.