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The eni Petroleum Nikaitchuq field is located offshore in the Beaufort Sea within the North Slope region of Northern Alaska. The 12-1/4" intermediate section of the Nikaitchuq wells are drilled with a Rotary Steerable System (RSS) at high inclination prior to landing near-horizontal in the reservoir. The intermediate hole section passes through a very abrasive sand with an unconfined compressive strength (UCS) of approximately 22 ksi called the Lower Ugnu.Historically, the drilling of the 12-1/4" intermediate section has been drilled with two to three bit runs consisting of various polycrystalline diamond compact (PDC) and tri-cone designs. This was due to the abrasive nature of the Lower Ugnu combined with interbedded soft sand causing ledging, high stick-slip and lateral vibrations which lead to consequential bit/BHA damage and a reduction in drilling efficiency.With the objectives of drilling the section in one run and to minimize damages to the RSS and MWD, a vibration mitigation workshop was conducted between the Nikaitchuq drilling team and key service company experts. The workshop team focused on four strategies to mitigate vibrational issues:1. Bottom Hole Assembly modification.2. Introducing new technologies and tools into the drill string to capture high density data and mitigate vibration.3. Mapping and prediction of the hard streaks within the intermediate section.4. Modification of drilling practices where possible.BHA and bit vibration modeling, new vibration mitigation tools, Measurement While Drilling (MWD) and multi-axis downhole vibration measurement data, BHA and stabilizer reconfiguration, as well as implementing various drilling parameters were all investigated and applied in both the front end and at the rig site. This paper demonstrates the systematic approach the Nikaitchuq drilling team implemented to mitigate damage to the bit and downhole tools as well as improve drilling performance by minimizing stick-slip and lateral vibrations.

Saudi Aramco operates one of the largest offshore oilfield developments in the world. This field is made up of 41 kilometers of causeway, 3 kilometers of bridges, 27 drilling islands, 13 offshore platforms, and 16 onshore drill sites. The magnitude of the field has pushed cutting edge technology and processes to the forefront of the industry. This new development has driven achievements in multilateral and extended reach directional wells. One challenge the operator faces is to maintain proper hole cleaning in extended 8½ in. tangent sections at a 85-87°inclinations, which are drilled in excess of 10,000 ft.Historically, drilling very long tangent sections required the use of several tandem sweep pills, wiper trips, and reaming/back reaming to maintain hole quality and efficiently remove cuttings bed from the wellbore. The negative effects of poor hole cleaning can lead to tight intervals, increased torque and drag, and eventually stuck pipe.In an effort to drill efficiently, utilization of a new technology to increase the cutting removal was trial tested on well A1 from an onshore location of the field. The ERD well, A1, was drilled to a total depth of 30,480 ft MD (8,650 ft TVD) into a stratigraphic environment composed of limestone, shale, and siltstone. The objective of the trial test for the tool was to improve the drilling efficiency. To obtain the best possible hole cleaning, a simulation was performed by placing the tools every three stands along the tangent section in the 8½ in. hole section.The goal of the trial test was to achieve the following:• Enhance hole cleaning by removal of cuttings bed.• Reduce the frequency/number of tandem sweep pills.• Reduce the frequency/number of wiper trips.• Reduce torque and drag and compare it with the offset wells.• Reduce drilling cost.A service company installed a cuttings flow-meter system at the shakers, which was used to evaluate the hole cleaning efficiency and performance of the hole cleaning tools. This paper will demonstrate the systematic methodology, which Saudi Aramco and the service company used to approach the utilization of the hole cleaning tools to achieve a clean hole in well A1.

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