Well Delivery Optimization Through an Eccentric Reamer

Abstract The aim of any drilling engineer is to deliver a good-quality hole ensuring it’s smooth with minimum tortuosity and in-gauge. One of the tools that have been recently applied to improve the hole quality and improve the drilling performance overall is Dog Leg Reamer (DLR). This DLR is an effective tool not only to smooth any doglegs that lead to lowering the drag values but also to enhance the tripping time and make the wireline logging tools capable of reaching the well TD successfully. DLR is one of the components of the BHA that is based on the maximum toughness. The critical feature of that tool is its eccentric profile that enables the tool to pass through the under-gauge hole if no rotation applied. The placement of the DLR is very crucial and needs a BHA modelling to estimate the contact force and the bending stress ratio. As the DLR has its own cutting structure that’s used to smooth and enlarge the hole so the drill string with this DLR contains two cutting structures. It’s very important to study the distribution of the weight between those two cutting structures and estimate the generated torque from the bit and the DLR tool itself. Mechanical specific energy concept was the base of the developed mathematical model to compute the load distribution between the bit and the DLR tool. The developed model shows very good results that matches the actual field data. More than thirty-five successful DLR runs have been recorded at different fields covering different hole sizes. Through those different runs, the tool proved its capability to smooth the hole without interrupting the directional work control and helped to minimize the vibration level, enhanced the average ROP and ensured proper load transmission to the drilling bit. Including this downhole tool in the bottom hole assembly has its significant effect to save drilling and tripping time that will lead at the end to significant cost saving. DLR positive economic impact had been confirmed through different case studies that are available for this work.