Wellbore circulation system

Abstract

A system for continuously circulating fluid to and through a tubular string either of coiled tubing or made up of a plurality of tubulars connected end-to-end while an upper tubular is added to or removed from a top tubular of the plurality of tubulars, all tubulars having a top-to-bottom fluid flow channel therethrough, the system having an upper chamber with a bottom opening, a top opening, and an upper sealing apparatus for sealingly encompassing a portion of the upper tubular, a lower chamber with a bottom opening, a top opening and a lower sealing apparatus for sealingly encompassing a portion of the top tubular, one of the upper chamber and the lower chamber sized for accommodating connection and disconnection therein of the upper tubular and the top tubular, and gate apparatus between and in fluid communication with the upper chamber and the lower chamber. Such a system may have apparatus for isolating a tubular therein from an axial load imposed by fluid pressure in a chamber; at least one of the lower chamber and the upper chamber with inner bushing apparatus with a portion thereof movably disposable within the chamber's sealing apparatus for facilitating movement of a tubular with respect to the chamber's sealing apparatus, and the system connectible to and rotatable by a rotating system for rotating the tubular string; and/or heave compensation interconnections for interconnecting the system to an offshore rig's heave compensation system. The system in certain aspects including fluid flow lines to each of the top and bottom chambers, a supply of fluid for circulating through the tubular string and through the upper and lower chambers, apparatus for continuously moving circulating fluid from the supply through the system into the tubular string.