Method and apparatus for rotating casing string segment

In a casing string having an upper part located in a relatively highly deflected portion of a well bore characterized by walls and extending upwardly to the surface, and further having a segment of substantially the same external diameter as the upper part located in a rotation enabling portion of the well bore beyond the deflected portion, apparatus for rotating the casing segment and circulating fluid material into the annulus between the well bore and the casing segment, the apparatus comprising:

• a swivel between the casing segment and the upper part of the casing string, the swivel including a stationary portion fixed to the upper part and a rotatable portion fixed to the casing segment;
• sealing and bearing means disposed between the stationary and rotatable portions and enabling fluid tight relative rotation therebetween;
• and drive means fixed to the rotatable portion and engagable by a drill string for rotation of the rotatable portion to rotate the casing segment relative to the upper part of the casing string;
• means on the casing segment extending into the annulus for sweeping through the annulus and engaging the adjacent well bore surfaces during rotation of the casing segment;
• centralizer means mounted to the casing string adjacent the swivel and tending to maintain the swivel in spaced relation to the adjacent well bore walls;
• and
• means on the swivel enabling passage of fluid material from the drill string, through the swivel, and to the casing segment for passage out of the casing segment and into the annulus during rotation of the casing segment.

A method of rotating a segment of a casing string extending from the surface into a well bore having a relatively highly deflected well bore portion, the method comprising the steps of:

• providing a rotation enabling portion in the well bore beyond the deflected well bore portion;
• making up a casing string having a swivel between a segment of the string and the remainder of the string to render the casing segment rotatable relative to the remainder of the string;
• running the casing string into the well bore in spaced relation to the well bore sufficient to provide a drilling mud passage along the exterior of the casing segment and the remainder of the sting for carrying drilling mud to the surface, and locating the casing segment in the rotation enabling portion of the well bore;
• running a drill string through the casing string and into driving engagement with the swivel;
• rotating the drill string to rotate the casing segment relative to the remainder of the casing string;
• and
• passing drilling mud down the drill string, out of the casing segment and into the drilling mud passage during rotation of the casing segment.

In combination with a casing string having an upper part located in a relatively highly deflected portion of a well bore characterized by walls and extending upwardly to the surface, and further having a segment located in a rotation enabling portion of the well bore beyond the deflected portion, and wherein the upper part and the segment of the casing string are spaced from the well bore sufficiently to provide a drilling mud passage along the exterior of the casing string for carrying drilling mud to the surface, apparatus for rotating the casing segment and circulating fluid material into the drilling mud passage between the well bore and the casing segment, the apparatus comprising:

• a swivel between the casing segment and the upper part of the casing string, the swivel including a stationary portion fixed to the upper part and a rotatable portion fixed to the casing segment;
• sealing and bearing means disposed between the stationary and rotatable portions and enabling fluid tight relative rotation therebetween;
• and drive means fixed to the rotatable portion and engagable by a drill string for rotation of the rotatable portion to rotate the casing segment relative to the upper part of the casing string;
• means on the casing segment extending into the drilling mud passage for sweeping through the drilling mud passage and engaging the adjacent well bore surfaces during rotation of the casing segment;
• centralizer means mounted to the casing string adjacent the swivel and tending to maintain the swivel in spaced relation to the adjacent well bore walls;
• and
• means on the swivel enabling passage of fluid material from the drill string, through the swivel, and to the casing segment for passage out of the casing segment and into the drilling mud passage during rotation of the casing segment.

A method of rotating a segment of a casing string extending from the surface into a well bore having a relatively highly deflected well bore portion, the method comprising the steps of:

• providing a rotation enabling portion in the well bore beyond the deflected well bore portion;
• making up a casing string which is structurally continuous along its exterior surfaces to define a drilling mud passage between the casing string and the well bore for carrying fluid materials to the surface along the exterior of the casing string, and providing a swivel between a segment of the string and an adjacent portion of the string to render the casing segment rotatable in the rotation enabling portion of the well bore, and relative to the adjacent portion of the string;
• running the casing string into the well bore and locating the casing segment in the rotation enabling portion of the well bore;
• running a drill string through the casing string and into driving engagement with the swivel;
• and
• rotating the drill string to rotate the casing segment relative to the adjacent portion of the casing string.