Abstract: A modular noise-insulating device for offshore pile driving, comprising interconnected noise-insulating modules movably nested in a telescopic arrangement in a storage position and constructed to move telescopically relative to each other, wherein the noise-insulating modules are substantially homogeneous or comprise a noise-insulating portion providing a buoyant force and a ballast portion providing a gravitational force, wherein in a surrounding liquid in the operating position, each noise-insulating module arranged above the bottom module provides a ratio of a total buoyant force versus a total gravitational force provided by said noise-insulating module, said ratio being in a first range of ratio between 1 and 5, the bottom module provides a second ratio of a total buoyant force of said bottom module versus a total gravitational force of said bottom module, said second ratio being below a maximum ratio of said noise-insulating modules.

Abstract: A method of operating a drill string includes receiving signals indicative of rotation of a bottom hole assembly (BHA) of the drill string; receiving signals indicative of the torque experience by the BHA; determining from the received signals an average slipping torque and a maximum sticking torque; determining a friction ratio based on the maximum sticking torque and the average slipping torque; and generating an indication that the friction ratio exceeds a limit.

Abstract: A method of operating a drill string includes receiving signals indicative of rotation of a bottom hole assembly (BHA) of the drill string; receiving signals indicative of the torque experience by the BHA; determining from the received signals an average slipping torque and a maximum sticking torque; determining a friction ratio based on the maximum sticking torque and the average slipping torque; and generating an indication that the friction ratio exceeds a limit.