Application of Novel Technology Improves Drilling Performance in Multilateral Field Development Offshore West India—Reducing Risk and Increasing Production

摘要

The Panna Field is located offshore West India and is operated by BG Exploration and Production India Limited. The reservoir is a tight limestone which is drained using multi- lateral wells. There are significant drilling challenges. Firstly, the well trajectories are complex to reach the reservoir and the laterals are three dimensional profiles requiring precise steering control to maintain position in the productive zones. Secondly, total fluid losses to the fractured limestone are frequently encountered. Thirdly, high levels of vibration and high drilling torque threaten the integrity of the drillstring and ultimately limit the reach to which the lateral sections can extend. A rotary closed loop drilling system had been use to successfully drill the wells, but the desire to improve gross drilling performance, reduce the risk to drillstring and extend the reach of the laterals prompted introduction of a new drilling system which was being tested in the North Sea. This new system integrates a high performance drilling motor with high speed rotary closed loop system to improving overall drilling performance in challenging areas, reduce stress on the drillstring and enable wells to extend past prior reach limits. On the first well; rate of penetration increased by 46%, the distance drilled per BHA increased by over 300% and the longest ever lateral in the field was successfully drilled. Based on the performance noted on the initial well, the new system was used on a further six Panna tri-laterals - completing the drilling campaign ahead of schedule. This paper discusses challenges drilling to and through the Panna field reservoir with the reasoning behind mobilization of the new drilling system to the area at an early phase of its introduction. The overall results of drilling the tri-laterals are then presented.