초록 ▼

A tubing hanger (2) is suspended in a spool (1) by a composite load support ring (7,8). Upon running-in, the hanger expands the ring into engagement with complementary grooves (34) in the spool wall. By making the load support ring from individual split rings (7,8), a radially large bearing area is

A tubing hanger (2) is suspended in a spool (1) by a composite load support ring (7,8). Upon running-in, the hanger expands the ring into engagement with complementary grooves (34) in the spool wall. By making the load support ring from individual split rings (7,8), a radially large bearing area is provided for supporting the hanger and/or a seal, whilst enabling an appreciable expansion of the ring without it yielding beyond its elastic limit.

대표청구항 ▼

A wellhead comprising: a) a suspension assembly for a tubing or casing string, the assembly comprising: a radially expandable composite load support ring comprising a radially innermost first metallic split ring and a radially outermost second metallic split ring which are interconnected so that axi

A wellhead comprising: a) a suspension assembly for a tubing or casing string, the assembly comprising: a radially expandable composite load support ring comprising a radially innermost first metallic split ring and a radially outermost second metallic split ring which are interconnected so that axial and radial forces can be transmitted from the first ring to the second ring, the radially outer surface of the second ring being formed with a plurality of axially spaced annular ribs for engagement, upon radial expansion of the composite ring, with complimentary annular grooves in a surrounding tubular wellhead member to fix the composite ring in the wellhead member, and the radially inner surface of the first ring being formed with a frusto-conical taper such that relative axial movement of a complimentary frusto-conical surface in engagement with the taper will expand the composite ring radially outwardly; a hanger being formed by the complimentary frusto-conical surface and a shoulder to land on the composite load support ring when the load support ring has been fully expanded; b) a tubular wellhead member having annular grooves to receive the annular ribs of the load support ring, and the radial dimensions of the first and second rings of the load support ring and of the necessary radial expansion of the load support ring to engage the grooves of the wellhead member being such that, when the load support ring is fully expanded, the first and second rings have been deformed within their elastic limit; c) a blocking ring upon which, prior to fixing in the tubular wellhead member, the unexpanded load support ring seats, the load support ring being fixed against horizontal displacement on the blocking ring by means of shear elements which are arranged to shear when the load support ring is expanded, the blocking ring being further prevented from moving axially on the hanger by shear elements which, when in use, the assembly is lowered into the wellhead member and the blocking ring meets an obstruction, shear to allow the hanger to move down relatively to the blocking ring and load support ring to expand the load support ring; d) a sealing assembly carried by and surrounding the hanger for sealing the hanger to the wellhead member, the sealing assembly being set by compression between a shoulder on the hanger and the load support ring during a final downward movement of the hanger relatively to the load support ring; e) a metallic split lockdown ring carried by and surrounding the hanger, the lockdown ring being formed on the radially outer surface of the hanger with a plurality of axially spaced annular ribs for engagement, upon radial expansion of the lockdown ring, with complimentary annular grooves in the wellhead member and, on its radially inner surface with a downwardly and radially inwardly frusto-conical taper; f) a lockdown sleeve which is carded by and surrounding the hanger and which is screwed relatively to the hanger and having a radially outer frusto-conical surface complimentary with that of the locking ring whereby the locking ring may be expanded upon screwing of the sleeve along the hanger; and g) an annular carrier onto which the lockdown sleeve is screwed, the annular carrier being locked axially on the hanger by pins and J-slots, and against rotation relatively to the hanger by shear elements which, in the event of seizure of screw threads between the lockdown sleeve and the carrier, are arranged to shear to allow rotary and axial movement of the carrier to disengage the pins from their J-slots and hence allow axial movement of the lockdown sleeve and retraction of the lockdown ring.