Pushing the Limits of ERD: Integrating Mechanical and Hydraulic Simulations for Efficient Well Planning

Abstract Extended reach wells have been pushing the envelope when it comes to lateral lengths, making drilling operations increasingly complex. Selecting the appropriate drill pipe and casing geometry and connection types is essential to withstand the substantial torques generated. Drill pipe selection impacts equivalent circulating density (ECD) and hole cleaning, requiring an integrated approach, combining both mechanical and hydraulic analysis, to assess the actual feasibility of drilling such wells. A drilling campaign in a mature field presents challenges beyond ERD profiles, with water base mud and depleted reservoirs introducing added complexities such as abnormally high friction factors and narrow drilling windows. Iterative Torque/Drag/Buckling (stiff-string model-based) and Hydraulic simulations were conducted for multiple tapered string combinations. The results, combined with operational constraints, guided the selection of the string configuration that deemed the planned well total depths (TDs) feasible. For cases where planned TDs not met, sensitivity analysis determined the maximum achievable TD. Casing running was modeled for each scenario, including comprehensive screening of high-performance connection providers. The detailed results from the iterative Torque/Drag/Buckling and Hydraulic simulations enabled the operator to optimize the drill string configuration by selecting drill pipes that maximize the total depth of the planned wells, increasing the overall production lengths of the field. Additionally, considering the adjusted total well depths, casing and liner running operations were simulated using different methodologies, including washing down, rotating, and floating the string. Simultaneously, the suitable casing connections were determined from the casing providers screening process, enabling the necessary adjustments in well architecture (section TD) and casing selection. The benefits of these iterative simulations are twofold: first, they reduce costs by optimizing tubular mobilization for the entire drilling campaign while maximizing drain length. Second, by incorporating refined engineering analysis into the early planning stages, they enable early identification and mitigation of mechanical and hydraulic complications during drilling operations. Iterative modeling of Torque/Drag/Buckling and Hydraulics identifies the sweet spot between mechanical/hydraulic drilling constraints and drain length optimization. Mastering these constraints is critical for pushing ERD wells limits, while also enhancing performance in conventional wells by designing the most efficient drill string and casing/liner string for each application.