Integrated Engineering Solutions for Drilling Extended Reach Multilateral Wells with Lateral Sections More Than 2000 Meters with the Use of Mud Motor. Successful Experience in Tazovskoye Field

Abstract Rotary Steerable Systems (RSS) are, in general, more efficient versus Positive Displacement Motors (PDM) when drilling the wells under complicated geological conditions. Thousands of operations, performed all over the world, clearly confirm this statement (Wardana, R, 2019). However, this paper will demonstrate that there are geological features where the main advantage of RSS – drilling with constant rotation – is not efficient and may result in emergency situations. Specifically, under such geological conditions it is necessary to drill in Tazovskoye field which is developed by extended reach horizontal and multilateral wells. This paper will cover integrated engineering solutions, which made it possible to overcome geological challenges to reduce the costs of drilling extended reach multilateral wells by a deliberate engineered change from RSS to PDM application. The approach was confirmed in 11 multilateral wells, drilled with the use of PDM. In this case the length of each horizontal hole totaled 2000 meters and more. An all-time record was achieved in Russia in terms of the length of horizontal wells, drilled with PDM motors without using oil-based mud: a horizontal section 2,520 meters in length with DDI – 6.72, ERD – 2.67 was drilled.