Multi-bowl wellhead assembly and method of completing a well

A method of completing a well, comprising:

• (a) extending a conductor pipe into the well and connecting a riser to an upper end of the conductor pipe with a riser connector, the riser connector sealingly engaging an outer diameter of the conductor pipe and then providing a wellhead with a bore, a rim, and external threads on an outer diameter portion of the wellhead joining the rim, the riser connector comprising a slip and an energizing member configured to engage the slip to grip the outer diameter of the conductor pipe;
• (b) securing an upper end of a surface casing string to the wellhead, securing a running tool to the external threads, lowering the wellhead onto a base at an upper end of the well, then cementing the surface casing string;
• (c) providing a hub with internal threads and an external circumferential stepped recess, removing the running tool, and securing the hub to the external threads;
• (d) providing a blowout preventer, a connector spool, and an annular locking member having a plurality of locking elements, bolting the blowout preventer to the connector spool wherein the connector spool is secured to the annular locking member to define a blowout preventer assembly and landing the blowout preventer assembly on the hub and moving the locking elements inward into engagement with the recess;
• (e) drilling the well through the blowout preventer assembly and cementing at least one inner casing string in the well, the at least one inner casing string extending from a hanger within the wellhead, the hanger restrained within the wellhead with a restraining assembly entirely internal to the wellhead;
• then
• (f) removing the blowout preventer assembly and the hub and securing a threaded flange having bolt holes to the external threads;
• and
• (g) bolting a tubing head to the bolt holes of the threaded flange.

A method of completing a well, comprising:

• (a) connecting a riser to an upper end of a conductor pipe extending into the well with a riser connector, the riser connector sealingly engaging an outer diameter of the conductor pipe, the riser connector comprising a slip and an energizing member configured to engage the slip to grip the outer diameter of the conductor pipe;
• (b) providing a wellhead with a support ring at its lower end and lowering the wellhead through the riser, the wellhead having external threads on an outer diameter;
• (c) landing the support ring of the wellhead on a landing ring located at an upper end of the conductor pipe;
• (d) removing the riser;
• (e) providing a hub with internal threads and an external circumferential stepped recess, and securing the hub to the external threads of the wellhead;
• (e f) providing a blowout preventer, a connector spool, and an annular locking member having a plurality of locking elements, bolting the blowout preventer to one end of the connector spool and connecting the annular locking member to an opposite end of the connector spool, defining a blowout preventer assembly, then landing the blowout preventer assembly on the hub, and engaging the locking elements with the recess;
• (f g) drilling the well through the blowout preventer assembly and restraining at least one hanger within the wellhead with a restraining assembly entirely internal to the wellhead;
• then
• (e h) removing the blowout preventer assembly and the hub and securing a threaded flange having bolt holes to the external threads of the wellhead;
• and
• (f i) bolting a wellhead member to the bolt holes of the threaded flange.

A method of completing a well, comprising:

• (a) extending a conductor pipe into the well and connecting a riser to an upper end of the conductor pipe with a riser connector wherein the riser connector sealingly engages an outer diameter of the conductor pipe, drilling through the riser and then providing a wellhead with a bore, a rim, and external threads on an outer diameter portion of the wellhead joining the rim, the riser connector comprising a slip and an energizing member configured to engage the slip to grip the outer diameter of the conductor pipe;
• (b) securing an upper end of a surface casing string to the wellhead, securing a running tool to the external threads, lowering the wellhead onto a base at an upper end of the well, then cementing the surface casing string and removing the riser from the upper end of the well;
• (c) providing a hub with internal threads and an external circumferential stepped recess, removing the running tool, and securing the hub to the external threads;
• (d) providing a blowout preventer, a connector spool, and an annular locking member having a plurality of locking elements, bolting the blowout preventer to the connector spool wherein the connector spool is secured to the annular locking member to define a blowout preventer assembly and landing the blowout preventer assembly on the hub and moving the locking elements inward into engagement with the recess;
• (e) drilling the well through the blowout preventer assembly and cementing at least one inner casing string in the well, the at least one inner casing string extending from a hanger within the wellhead, the hanger restrained within the wellhead with a restraining assembly entirely internal to the wellhead;
• then
• (f) removing the blowout preventer assembly and the hub and securing a threaded flange having bolt holes to the external threads;
• and
• (g) bolting a tubing head to the bolt holes of the threaded flange.

A system for coupling components to a wellhead coupled to a casing extending into a downhole formation, the casing being arranged within a conductor pipe that extends into the downhole formation, the system comprising:

• a top end of the wellhead comprising external threads;
• a removable hub extending radially outward from the wellhead and configured to selectively engage the external threads on the top end of the wellhead, said removable hub comprising:
• an external downward facing sloped surface and adjacent axial surface, both surfaces combining to form a recess;
• an annular locking member comprising a plurality of locking elements configured to move radially inward to engage the external downward facing sloped surface of the recess, wherein each of the plurality of locking elements comprises a pin and a wedge-shaped engaging element, the wedge-shaped engaging element configured to mate to the recess, and the pin is threaded and rotatable relative to the wedge-shaped engaging element, and the wedge-shaped engaging element is configured to move inward and enter the recess when the pin is rotated;
• and
• a flange configured to selectively engage the external threads on the top end of the wellhead.

A method for performing operations at a well site including a wellbore, a conductor pipe arranged in a downhole formation, and a casing extending through the conductor pipe to a surface location with a connector, the connector sealingly engaged to an outer diameter of the conductor pipe, the riser connector comprising a slip and an energizing member configured to grip the slip to engage the outer diameter of the conductor pipe, the method comprising:

• connecting a riser to an upper end of the conductor pipe with a riser connector, the riser connector sealingly engaging an outer diameter of the conductor pipe;
• coupling a hub to a wellhead coupled to the casing;
• the hub having internal threads that engage external threads of the wellhead;
• landing a blowout preventer assembly on the wellhead;
• engaging the hub with an annular locking member of the blowout preventer assembly;
• the annular locking member including a plurality of locking elements configured to move radially inward to contact the hub;
• wherein a bottom surface of the blowout preventer assembly directly contacts a rim of the wellhead after the annular locking member engages the hub;
• removing the hub from the wellhead;
• and
• coupling a flange to the wellhead;
• the flange having internal threads that engage the external threads of the wellhead.

A system for conducting operations at a well site, the system comprising:

• a flange having internal threads that engage the external threads of the wellhead;
• a hub having internal threads configured to mate with external threads of a multi-bowl wellhead such that, upon engagement of the internal threads with the external threads, the hub is threadingly coupled to the multi-bowl wellhead, the hub further comprising a recess formed along an outer profile of the hub;
• a blowout preventer assembly comprising a blowout preventer, an annular locking member, and a quick connector spool;
• and
• the annular locking member configured with respect to the blowout preventer such that upon engaging the blowout preventer assembly with the hub, the annular locking member extends axially lower than the blowout preventer, the annular locking member including a plurality of locking elements configured to move radially inward to engage the recess, thereby coupling the annular locking member to the hub, and wherein a mating face of the blowout preventer assembly contacts the multi-bowl wellhead when the annular locking member is coupled to the hub, wherein each of the plurality of locking elements comprises a pin and a wedge-shaped engaging element, the wedge-shaped engaging element configured to mate to the recess, and the pin is threaded and rotatable relative to the wedge-shaped engaging element, and the wedge-shaped engaging element is configured to move inward and enter the recess when the pin is rotated.