A wellhead stabilization device for offshore drilling operations

Abstract

A wellhead stabilization device for marine drilling construction includes a suction anchor, a catheter and a catheter seat. An upper seat ring is provided on the upper part of the inner tube. The upper seat ring is a tapered hole at the lower part of the upper column. An outwardly convex suspension section is provided on the upper part of the catheter. An outer cone of the suspension section is provided at the lower part of the suspension section. A catheter seat is mounted on the suspension section. An inner cone surface of the catheter seat and an outer cone of the catheter seat are provided at the lower part of the catheter seat. The outer cone of the catheter seat matches and fits with the inner cone surface of the lower cone hole of the upper column. The outer cone of the suspension section matches and fits with the inner cone surface of the catheter seat. The present invention sets an upper seat ring on the top of the inner tube of the suction anchor, and adds a catheter seat. The catheter is installed in the upper seat ring through the catheter seat. Conical surfaces are matched between the catheter seat and the upper seat ring, and between the catheter and the catheter seat. With the synergistic effect of the guide strip, the concentricity of the catheter and the wellhead head and the suction anchor at the wellhead is ensured. The vertical deviation of the suction anchor installation is controlled within 1°, which can ensure that the vertical deviation of the catheter is controlled within 1°. The present invention also has the characteristics of easy disassembly and assembly.

Description

Technical Field

[0001] The present invention relates to a construction device for ocean drilling engineering, in particular to a wellhead stabilizing device for ocean drilling construction. Background Art

[0002] Wellhead stabilizing devices are widely used in ocean engineering. Their function is similar to that of rigid short piles, providing support and acting as a foundation for the wellhead. Traditional subsea drilling wellhead stabilizing devices consist of a conductor (also known as a casing) and a baseplate. The top of the conductor is the wellhead. Depending on the weight of the wellhead support equipment, generally, dozens to hundreds of meters of conductor and wellhead baseplate are required to jointly support the weight of the wellhead. The conductor is inserted into the seabed mud surface by jet drilling. The conductor needs to be lifted by a platform or a drilling ship for a period of time to wait for the formation to hold the conductor tightly or be cemented to ensure the tight connection between the conductor and the formation, thereby generating vertical bearing capacity. Traditional wellhead stabilizing devices have the following defects: 1. It is impossible to ensure the levelness of the wellhead baseplate and the verticality of the conductor, so it is impossible to ensure that the verticality of the wellhead is within 1°; 2. The time for conductor jetting and waiting for the conductor to stabilize is relatively long, and the cost of offshore construction operations is high; 3. When a deeper conductor needs to be inserted, the cost of the conductor is high. If a directional well or a horizontal well is drilled, the vertical section is relatively long, resulting in the kick-off point being at a deeper position, which is not conducive to the exploitation of shallow oil and gas resources. Summary of the Invention

[0003] The purpose of the present invention is to provide a wellhead stabilizing device for ocean drilling construction that can reduce the verticality error of the conductor, is fast in construction, and is easy to construct.

[0004] The present invention solves the above problems through the following technical solutions:

[0005] A wellhead stabilizing device for ocean drilling construction includes a suction anchor and a conductor. The suction anchor includes an inner pipe and an outer pipe. The conductor is located in the inner pipe. It also includes a conductor seat. An upper seat ring is provided at the upper part of the inner pipe. The upper seat ring has an upper cylindrical and lower conical hole. An outwardly protruding hanging section is provided at the upper part of the conductor. An outer conical table of the hanging section is provided at the lower part of the hanging section. A conductor seat is sleeved on the hanging section. An inner conical surface of the conductor seat and an outer conical table of the conductor seat are provided at the lower part of the conductor seat. The outer conical table of the conductor seat is matched and fitted with the inner conical surface of the upper cylindrical and lower conical hole, and the outer conical table of the hanging section is matched and fitted with the inner conical surface of the conductor seat.

[0006] For the above wellhead stabilizing device for ocean drilling construction, several groups of guiding rings are axially distributed on the inner wall of the inner pipe. Each group of guiding rings is composed of several evenly distributed guiding bars. The inner surface of each guiding bar is an outwardly convex arc surface. The inner diameter D of each group of guiding rings is in clearance fit with the outer diameter d of the conductor.

[0007] For the above wellhead stabilizing device for ocean drilling construction, several through-flow grooves are evenly distributed axially on the outer wall of the conductor seat.

[0008] The above-mentioned wellhead stabilization device for marine drilling construction is characterized in that an annular inner groove is provided on the upper part of the inner hole of the catheter seat, and an outer groove is provided on the hanging section of the catheter. The inner groove on the catheter seat corresponds to the position of the outer groove of the hanging section, and the open clamping ring is embedded in the outer groove, and the open clamping ring is clamped with the inner groove; each flow groove is provided with a through screw hole, and the position of the screw hole corresponds to the inner groove.

[0009] The above-mentioned wellhead stabilization device for marine drilling construction has evenly distributed stiffeners on the upper part of the suction anchor, the inner tube and the outer tube are connected by stiffeners, and the top of the outer tube is closed by a top plate; a transition bell mouth is provided on the top of the inner tube, the upper edge of the transition bell mouth is welded to the top plate, and the lower edge of the transition bell mouth is welded to the top of the upper seat ring.

[0010] The above-mentioned wellhead stabilization device for marine drilling construction has threaded holes on both sides of the opening of the open clamping ring, and tightening blocks are respectively installed on both sides of the opening. The tightening blocks and the open clamping ring are fixed by bolts. The fastening bolts and nuts are passed across the two tightening blocks. By screwing the fastening bolts and nuts together, the opening of the open clamping ring is closed and the open clamping ring shrinks inward.

[0011] The present invention is designed to solve the problems of the prior art, and its main advantages are as follows: 1. A catheter seat is added, and an upper seat ring for mounting the catheter seat is arranged on the upper part of the inner tube. The upper seat ring is in contact with the conical surface of the catheter seat and the conical surface of the catheter seat is in contact with the conduit, which plays an automatic centering role. The conduit and the suction anchor are well concentric. Since the verticality of the suction anchor can be controlled within 1°, the verticality deviation of the catheter can also be controlled within 1°; 2. A guide ring is arranged inside the inner tube of the suction anchor to further ensure the concentricity of the catheter body and the inner tube of the suction anchor; 3. The catheter seat and the catheter are connected by a guide ring. The open clamping ring constitutes a fixed connection. During installation, you only need to compress the open clamping ring to install the catheter seat onto the catheter hanging section. After it is in place, loosen the open clamping ring to lock it. When the catheter seat is removed, the open clamping ring can be shrunk by reinstalling and tightening the block, or by screwing bolts into the threaded holes around the annular groove. The bolts compress the open clamping ring and the catheter seat can be separated from the catheter, making disassembly and assembly convenient; 4. A flow groove is set on the outer circle of the catheter seat to provide a water passage to ensure that the mud sprayed from the catheter can return from the annular gap between the catheter and the inner tube, and return to the seabed mud surface through the groove without pressure holding. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below in conjunction with the accompanying drawings.

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle;

[0015] Figure 3 is a schematic diagram of the structure of the catheter seat;

[0016] Figure 4 is a sectional view of the conduit seat;

[0017] Figure 5 is a structural schematic diagram of the suction anchor;

[0018] Figure 6 is a structural schematic diagram of the conduit;

[0019] Figure 7 is a structural schematic diagram of the split clamp ring;

[0020] Figure 8 is Figure 7 A - A sectional view of

[0021] The reference numerals in the figure are as follows: 1, outer pipe; 2, inner pipe, 2 - 1, upper seat ring, 2 - 2, upper column and lower tapered hole, 3, rib plate, 4, transition bell mouth, 5, conduit, 5 - 1, conduit head, 5 - 2, suspension section, 5 - 3, outer card slot, 5 - 4, outer tapered table of suspension section, 6, conduit seat, 6 - 1, outer tapered table of conduit seat, 6 - 2, flow - through groove, 6 - 3, set screw hole, 6 - 4, inner card slot, 6 - 5, inner tapered surface of conduit seat, 7, top plate, 8, alignment strip, 9, split clamp ring, 9 - 1, tightening block, 9 - 2, bolt, 9 - 3, fastening bolt, 9 - 4, fastening nut, 9 - 5, clamp ring groove. Detailed implementation mode

[0022] Refer to Figure 1 、 Figure 5 and Figure 6 , the present invention includes a suction anchor and a conduit 5. The suction anchor is composed of an inner pipe 2 and an outer pipe 1 to form a double - layer cylinder structure, and the conduit is located inside the inner pipe. Several rib plates 3 are evenly distributed on the upper part of the suction anchor. The rib plates are trapezoidal plates. The upper part of the rib plates is welded to the top plate, one short side of one side of the rib plates is welded to the inner wall of the outer pipe, and one long side of one side of the rib plates is welded to the inner pipe to improve the stability of the suction anchor and the connection strength between the inner and outer pipes. The annular area between the top of the outer pipe and the inner pipe is closed by the top plate 7. The top plate is a conical surface to improve the compressive capacity. The inner pipe is provided with a transition bell mouth 4 at the top. The upper edge of the transition bell mouth is welded to the top plate, and the lower edge of the transition bell mouth is welded to the top of the upper seat ring. The conduit 5 is a tubular structure. The thick - diameter part at the top of the conduit is the conduit head 5 - 1, and the conduit head can continue to suspend equipment such as small - diameter casing or wellhead blowout preventer. The thick - diameter part at the upper part of the conduit is the suspension section 5 - 2, and the suspension section is the suspension connection part between the conduit and the suction anchor.

[0023] Refer to Figures 2 - 6, to solve the problems of the perpendicularity of the conduit and the concentricity between the conduit and the suction anchor, the present invention provides a conduit seat 6, and at the same time, an upper seat ring 2-1 for installing the conduit seat is provided inside the inner pipe. The upper seat ring is located at the upper part of the inner pipe, and the upper seat ring is a through upper column and lower conical hole 2-2. The conduit seat is a hollow cylinder, with a chamfer at the upper part of the conduit seat, and a conduit seat inner conical surface 6-5 and a conduit seat outer conical table 6-1 at the lower part of the conduit seat. An outwardly protruding suspension section 5-2 is provided at the upper part of the conduit, and a suspension section outer conical table 5-4 is provided at the lower part of the suspension section. The conduit seat is sleeved outside the suspension section, and the taper of the outer conical table 6-1 of the conduit seat is the same as that of the conical surface of the upper column and lower conical hole 2-2 of the upper seat ring, and the two are matched and fitted; the taper of the suspension section outer conical table 5-4 of the conduit is the same as that of the conduit seat inner conical surface 6-5, and the two are matched and fitted. With the above structure, a conical connection is formed between the conduit seat and the upper seat ring, and a conical connection is formed between the conduit seat and the conduit, thus ensuring the perpendicularity of the conduit and the concentricity between the conduit and the suction anchor. With the above structure, when the installation perpendicularity of the suction anchor is controlled within 1°, the perpendicularity of the conduit can be ensured to be controlled within 1°. A plurality of axially uniformly distributed through-flow grooves 6-2 are provided on the outer wall of the conduit seat along the axial direction. The through-flow grooves ensure that the slurry sprayed by the conduit can return upward from the annular gap between the conduit and the inner pipe, and return above the seabed mud surface through the through-flow grooves, avoiding the phenomenon of pressure buildup.

[0024] See Figure 1 , Figure 5 , Figure 6 , the present invention axially distributes several groups of alignment rings on the inner wall of the inner pipe. Each group of alignment rings is composed of several uniformly distributed alignment bars 8. The inner surface of each alignment bar is an outwardly convex arc surface, and there is a clearance fit between the inner diameter D of each group of alignment rings and the outer diameter d of the conduit. The guiding bars play a role in guiding the conduit during installation on the one hand, and can make the middle and lower parts of the casing concentric with the inner pipe on the other hand.

[0025] See Figures 2 - 6 , an annular inner card slot 6-4 is provided at the upper position of the inner hole of the conduit seat, and an outer card slot 5-3 is provided on the suspension section of the conduit. The inner card slot and the outer card slot are in corresponding positions. An open snap ring 9 is installed in the outer card slot of the suspension section, and the snap ring groove 9-5 of the open snap ring is clamped with the inner card slot of the conduit seat, and the conduit is connected to the conduit seat through the open snap ring. The open snap ring is contracted by the tightening block 9-1 to install and separate the conduit seat and the conduit. In addition, through holes are provided in each through-flow groove, and the positions of the through holes correspond to the inner card slots. The through holes are provided so that the set screws can be screwed into the through holes to touch and press the open snap ring, so that the open snap ring contracts and disengages from the inner card slot, and in case of emergency, the conduit seat and the conduit can be separated by this method.

[0026] See Figure 7, a snap ring groove 9-5 is provided on the outer wall of the split snap ring. Threaded holes are provided on both sides of the opening of the split snap ring 9. Tightening blocks 9-1 are respectively installed on both sides of the opening. The tightening blocks and the split snap ring are fixed by bolts 9-2. A fastening bolt 9-3 passes through between the two tightening blocks. By screwing the fastening bolt and the fastening nut 9-4, the opening of the split snap ring closes, and the split snap ring contracts inward.

[0027] When the present invention is in use, the installation sequence is as follows: Place the conduit horizontally, and compress the split snap ring sleeved on the suspension section through the tightening blocks. The large end of the conduit seat is inserted into the small end of the conduit. The outer conical surface of the suspension section of the conduit contacts the inner conical surface of the conduit seat for centering. After the split snap ring enters the inner card slot, release the split snap ring, so that the conduit and the conduit seat are connected as a whole. Even when the conduit is erected, the conduit seat will not fall off. The pressure received by the conduit head is transmitted to the conduit seat through the conduit; after the conduit and the conduit seat are connected as a whole, the whole is inserted into the center of the inner tube of the suction anchor. During the insertion process, the centering ring composed of the centering strips always ensures that the conduit and the inner tube are concentric. When the outer conical surface of the conduit seat contacts the inner conical surface of the upper column and lower conical hole on the upper seat ring, the centering insertion is completed, and the conduit seat and the upper seat ring remain concentric. The force received by the conduit seat is transmitted to the upper seat ring through the outer conical surface of the conduit seat. The upper seat ring is a part of the whole anchor, so finally the force is transmitted to the suction anchor.

[0028] The conduit seat and the conduit are fixed together by a split snap ring. When separation is required, the split snap ring can be contracted through the tightening blocks, and the split snap ring is disengaged from the inner card slot to achieve the separation of the conduit seat and the conduit. In case of emergency, if the split snap ring cannot be contracted through the tightening blocks, a jackscrew can be screwed into the jackscrew hole of the conduit seat, and the jackscrew presses against the split snap ring to force the split snap ring to disengage from the inner card slot, and the conduit seat can be separated from the conduit.

[0029] The conduit is usually dozens of meters long, and the above process is completed underwater. The suction anchor is first sunk below the seabed mud surface, and then the conduit is installed. In special cases where the conduit is shorter, it can be inserted into the inside of the suction anchor and suspended in advance before the suction anchor is lowered into the water. The conduit, the conduit seat, and the wellhead suction anchor are lowered to the seabed together and installed as a whole below the seabed mud surface.

Claims

1. An on - wellhead stabilizing device for ocean drilling construction, comprising a suction anchor and a conductor pipe (5). The suction anchor includes an inner pipe (2) and an outer pipe (1), and the conductor pipe is located inside the inner pipe. It is characterized in that: It further includes a conductor pipe seat (6). An upper seat ring (2 - 1) is provided at the upper part of the inner pipe. The upper seat ring has an upper cylindrical and lower conical hole (2 - 2). An outward - protruding suspension section (5 - 2) is provided at the upper part of the conductor pipe, and an outer conical platform (5 - 4) of the suspension section is provided at the lower part. A conductor pipe seat (6) is sleeved on the suspension section. An inner conical surface (6 - 5) and an outer conical platform (6 - 1) of the conductor pipe seat are provided at the lower part of the conductor pipe seat. The outer conical platform of the conductor pipe seat is matched and fitted with the inner conical surface of the upper cylindrical and lower conical hole, and the outer conical platform of the suspension section is matched and fitted with the inner conical surface of the conductor pipe seat. A plurality of groups of guiding rings are axially distributed on the inner wall of the inner pipe. Each group of guiding rings is composed of several uniformly - distributed guiding strips (8). The inner surface of each guiding strip is an outward - convex arc surface. The inner diameter D of each group of guiding rings has a clearance fit with the outer diameter d of the conductor pipe. The on - wellhead stabilizing device is also provided with an open - type snap ring. Threaded holes are provided on both sides of the opening of the open - type snap ring. Tightening blocks (9 - 1) are installed on both sides of the opening. The tightening blocks and the open - type snap ring are fixed by bolts (9 - 2). A fastening bolt (9 - 3) penetrates between the two tightening blocks, and the fastening bolt is screwed with a fastening nut (9 - 4).

2. The on - wellhead stabilizing device for ocean drilling construction according to claim 1, It is characterized in that: A plurality of through - flow grooves (6 - 2) are uniformly distributed axially on the outer wall of the conductor pipe seat.

3. The on - wellhead stabilizing device for ocean drilling construction according to claim 2, It is characterized in that: An annular inner clamping groove (6 - 4) is provided at the upper part of the inner hole of the conductor pipe seat. An outer clamping groove (5 - 3) is provided on the suspension section of the conductor pipe. The inner clamping groove of the conductor pipe seat corresponds to the position of the outer clamping groove of the suspension section. The open - type snap ring (9) is embedded in the outer clamping groove, and the open - type snap ring is clamped with the inner clamping groove; A through - hole set - screw hole (6 - 3) is provided in each through - flow groove, and the position of the set - screw hole (6 - 3) corresponds to the inner clamping groove.

4. The on - wellhead stabilizing device for ocean drilling construction according to claim 1, It is characterized in that: Reinforcing plates (3) are uniformly distributed at the upper part of the suction anchor. The inner pipe and the outer pipe are connected by the reinforcing plates. The top of the outer pipe is closed by a top plate (7); A transition bell mouth is provided at the top of the inner pipe. The upper edge of the transition bell mouth is welded to the top plate, and the lower edge of the transition bell mouth is welded to the top of the upper seat ring.

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