Methods and apparatus for subsea well intervention and subsea wellhead retrieval

A method of cutting a casing string in a subsea well, the method comprising:

• positioning a tool proximate a subsea wellhead, wherein the tool has at least one grip member and wherein the tool is attached to a cutting assembly;
• operating the at least one grip member to clamp the tool to the subsea wellhead;
• cutting the casing string below the subsea wellhead by utilizing the cutting assembly;
• and
• applying an upward force to the tool during the cutting of the casing string which is at least equal to an axial reaction force generated from cutting the casing string, wherein at least a portion of the upward force is created by a cylinder member in the tool that acts on the subsea wellhead.

An apparatus for cutting a casing string in a subsea well, the apparatus comprising:

• a cutting assembly configured to cut the casing string;
• a grip member for engaging a subsea wellhead, the grip member movable between an unclamped position and a clamped position;
• and
• a lifting assembly configured to generate an upward force which is at least equal to an axial reaction force generated from cutting the casing string, wherein the lifting assembly comprises a piston and cylinder arrangement that is configured to act upon a portion of the subsea wellhead.