This paper presents a case study of drilling of three horizontal wells, drilled as a part of fifteen wells onshore in-fill drilling campaign in a highly dense field, with 300+ wells in a span of 14 sq. km. The well design aspects, directional planning and implementation of innovative parameter monitoring tool for efficient drilling operation and accurate well placement is discussed in detail. Additionally, paper discusses in detail, re-engineering and limit extension of cold-stacked 1000 HP drilling rig to achieve the drilling objectives.

"Measure & Manage" approach was practiced at each and every stage while planning these wells to make them "drillable" utilizing the existing resources. To drill these complicated horizontal wells, a 1000 HP drilling rig which was in cold-stack condition was the only available option. The rig was made fit for successfully drilling these complicated horizontal wells by planning and optimizing the utilization of rig equipment viz. mud pump, rig tubulars, top drive etc. within its safe working & endurance limits. The well path was finalized after multiple iterations to ensure the well trajectory is free of collision threats from nearby drilled wells and also geological objective of draining the zone of high oil saturation is achieved hand in hand. Detailed Torque and Drag (T&D) and hydraulics model was prepared and analyzed for each operational step and every hole sections to identify the correct boundary line parameters for each operation. Based on these analyses bottom hole assembly (BHA) and bits were selected to deliver best possible ROP & directional control. All the drilling parameters critical to the operation were measured and monitored using"drilling parameters dashboard" to ensure that they are within the boundary limits as defined while planning the well. Friction factors were modelled, calibrated and measured on every trip to judge the hole condition for subsequent operations. Geo-steering was implemented while drilling the drain hole section of the wells for accurate well placement into the reservoir.

As a result of detailed step by step planning, accurate measurement and meticulous approach the three horizontal wells, which appeared practically undrillable with the available drilling rig & associated resources on first look, were drilled successfully. The actual time taken to drill these wells was within the planned time and within the allocated budget.

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