CN211287579U

CN211287579U - Seabed wellhead assembly

Info

Publication number: CN211287579U
Application number: CN201922488639.XU
Authority: CN
Inventors: 王国栋; 陈国明; 岳吉祥; 周扬理; 马立安; 王铭; 尹晓丽; 刘锡胜; 余敏
Original assignee: China University of Petroleum East China; Shengli College China University of Petroleum
Current assignee: China University of Petroleum East China; Shengli College China University of Petroleum
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-08-18
Anticipated expiration: 2029-12-31

Abstract

The utility model discloses a seabed wellhead assembly, the outer sleeve consolidates with the surrounding stratum through cement for fixed wellhead assembly supports the weight of whole kill-job device, one part of inner skleeve is located the outer sleeve inside, another part is located the outer sleeve below, be equipped with floating piston between outer sleeve and the inner skleeve, be equipped with the packer in the inner skleeve, kill-job fluid is arranged in the outer sleeve above the floating piston, be the kill-job mud flow space in the inner skleeve, the drilling rod is arranged in the inner skleeve, the oral area of inner skleeve is equipped with the suction module, the suction module is connected the subsea; the floating piston is able to slide up and down along the inner sleeve. The beneficial effects of the utility model are that prevent that no marine riser mud from lifting the drilling operating mode and worsening, be suitable for the kill job of realizing kick/blowout initial stage operating mode, prevent that abominable occurence of failure from taking place.

Description

Seabed wellhead assembly

Technical Field

The utility model belongs to the technical field of the equipment kill-job machinery of ocean drilling, a seabed wellhead assembly that is used for no marine riser mud to lift well drilling and can realize the kill-job function is related to.

Background

The drilling technology without the riser mud lifting is one of the realization schemes of the double-gradient drilling technology, and can effectively solve the problem of deep water surface layer drilling. According to the technology, a marine riser is not used, a drill rod is in direct contact with seawater, the borehole return mud contained in an inner cavity of a suction module is sealed from the seawater by means of subsea pump control, and the borehole return mud containing rock debris is lifted to a platform through a mud return pipeline for treatment and recycling. The requirement of the non-riser mud lifting drilling technology on safe operation is as follows: 1) the drilling pressure can be controlled between a narrow window between the formation pore pressure and the fracture pressure; 2) the abnormal working condition of the well kick/blowout can be quickly processed. The original marine riser-free mud lifting drilling system equipment and the structural characteristics of a wellhead structure cannot realize well killing under abnormal working conditions (particularly well kick/blowout), and the bottom hole pressure can be controlled only by adjusting the rotating speed of a leveling platform pump and a seabed pump, so that a large drilling risk exists.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a seabed wellhead assembly, the beneficial effects of the utility model are that prevent that no marine riser mud from lifting the drilling operating mode and worsening, be suitable for the killing well operation of realizing kick/blowout initial stage operating mode, prevent that abominable occurence of failure from taking place.

The technical proposal adopted by the utility model is that the device comprises an outer sleeve, an inner sleeve, a floating piston and a packing device; the well killing device comprises an outer sleeve, an inner sleeve, a floating piston, a packer, a well killing liquid, a drilling rod, a suction module and a subsea pump, wherein the outer sleeve is consolidated with surrounding strata through cement and used for fixing a wellhead device and supporting the weight of the whole well killing device; the floating piston is able to slide up and down along the inner sleeve.

Drawings

FIG. 1 is a schematic structural view of the device of the present invention applied to a wellhead of a subsea mud lift drilling System (SMD);

FIG. 2 is a schematic structural view of the device of the present invention in which the floating piston moves downward and the packer is closed;

FIG. 3 is a schematic structural view showing the separation of the inner and outer rings of the piston when the device of the present invention realizes the kill function;

fig. 4 is a schematic structural diagram of the device of the utility model used in the deep water full well depth SMD scheme.

In the figure, 1, an outer sleeve, 2, an inner sleeve, 3, a floating piston, 4, a packing device, 5, a drill pipe, 6, a subsea pump, 7, a suction module and 8, a kill mud inlet are arranged.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The utility model is shown in figure 1 and comprises an outer sleeve 1, an inner sleeve 2, a floating piston 3 and a packing device 4; the well killing device comprises an outer sleeve, an inner sleeve 2, a floating piston 3, a packer 4, well killing liquid, a well killing mud flowing space, a drill rod 5, a suction module 7 and a subsea pump 6, wherein the outer sleeve is consolidated with surrounding strata through cement and used for fixing a wellhead device and supporting the weight of the whole well killing device, one part of the inner sleeve 2 is positioned inside the outer sleeve 1, the other part of the inner sleeve is positioned below the outer sleeve 1 and is equivalent to a sleeve, the floating piston 3 is arranged between the outer sleeve 1 and the inner sleeve 2, the packer 4 is arranged in the inner sleeve 2, the well killing liquid is arranged in the outer sleeve 1 above the floating piston 3, the inner sleeve; the floating piston 3 can slide up and down along the inner sleeve 2, the floating piston 3 plays a role in packing and isolating kill mud and shaft fluid under normal working conditions, when well kick occurs and kill operation needs to be carried out, the inner ring and outer ring connecting pins of the floating piston 3 can be sheared by the packing device 4 at the bottom of the inner sleeve 2 under the pressure of the kill mud to realize the separation of the inner ring and the outer ring, the outer ring is settled on the lower part of the inner sleeve 2 under the action of self gravity and the pressure of the kill mud, so that a flow path between the kill mud and the shaft is opened, and the kill operation can be carried out. The packer 4 is used for limiting the floating piston 3 up and down along the inner sleeve 2 and providing a supporting force for the inner ring of the floating piston 3, and the pressure difference formed by the supporting force and the pressure of the kill mud acting on the upper part of the floating piston 3 provides a shearing force required by the fracture of the connecting pin of the inner ring and the outer ring of the floating piston 3.

The kill-job device can be integrally put into a seabed wellhead after being assembled by adopting a platform, or the outer sleeve 1 is put into the seabed wellhead firstly, the floating piston 3, the packing device 4 and the inner sleeve 2 are combined and then put into the seabed together by adopting a drill rod 5 and a connector, the connection and fixation of the inner sleeve and the outer sleeve are realized on the seabed, and the separation of the inner ring and the outer ring of the floating piston 3 is realized by the pressure of injecting kill-job mud; the auxiliary control of the bottom hole pressure is realized by the up-and-down floating of the floating piston 3; wellbore closure is achieved by means of the packoff 4 and closing of the drill pipe 5 valve.

Fig. 1 is the utility model discloses an import configuration scheme embodiment structure schematic diagram of realization kill-job function, drilling rod 5 are creeping into the in-process, and drilling mud pours into the shaft bottom through drilling rod 5 and erodees the detritus into, makes the detritus return to the seabed well head on the annular space in the pit shaft, returns to the platform on the pipeline and handles circulation and recycle under the effect of seabed pump 6 via mud. The mud in the suction module 7 is controlled to keep stable with the seawater interface 2 by the rotation speed regulation of the seabed pump 6. Kill mud is injected into the upper space of the floating piston 3 in the outer sleeve 1 through a kill mud inlet 8 through a kill pipeline, under the normal working state, the upper pressure of the floating piston 3 and the lower bottom hole return mud reach a balanced state, the floating of the floating piston 3 is relied on, which is equivalent to increasing the internal capacity of the seabed suction module 7, thereby a larger time margin is left for the control and adjustment of equipment such as a seabed pump 6 and the like, the pressure of the seabed pump inlet is favorably kept equal to the seawater static pressure at the seabed, the bottom hole pressure is indirectly controlled to be kept in a drilling window between the formation pore pressure and the rupture pressure, and the purpose of safe drilling is achieved.

As shown in figure 2, in the initial stage of the well kick, the injection pressure of the well killing mud is increased, the floating piston 3 is contacted with the top of the lower packer 4, and due to the special structure of the inner ring of the floating piston 3, the packer 4 starts to act to hold the drill pipe 5, so that the well bore annulus is packed, and at the moment, the stable interface of the mud and the seawater is kept by controlling the rotating speed of the subsea pump 6.

As shown in fig. 3, when the well kick is severe and the killing operation is required, the injection pressure of the killing mud is increased, and when the pressure of the killing mud exceeds a certain value, the inner and outer ring connecting pins of the floating piston 3 falling to the position of the packer 4 are sheared, and the inner and outer rings of the piston are separated. The outer ring of the piston slides down under the pressure of the kill mud to fall below the packing device 4, the inner ring falls above the packing device 4, and the kill mud is injected into the well from the outer annular space of the packing device 4 to realize kill.

As shown in figure 4, when a well kick or blowout emergency occurs, the floating piston 3 is jacked to the position of a wellhead under the action of bottom pressure, a channel for fluid in the well to flow out from the annular space of the casing is closed, at the moment, the underground packer 4 tightly holds the drill rod under the action of bottom pressure, the annular channel in the outer sleeve 1 of the drill rod 5 is closed, meanwhile, the valve of the drill rod 5 closes the channel in the drill rod, the well shut-in function is realized, and the fluid is prevented from returning to a platform through the drill rod 5 to cause serious consequences. Along with the increase of the water depth, the drilling window is narrower, and the double-gradient effect is obviously weakened in the drilling process of the lower well section outside the surface layer. By adopting the device, an additional pressure is applied at the wellhead position, and the double-gradient effect can be enhanced by adjusting the pressure, so that the SMD system can be applied to a lower well section outside a deep water surface layer and even a full-well deep drilling well.

The packing device installed on the inner sleeve has the characteristic of acting by the upper and lower pressure difference in the inner and outer sleeve annuluses. The floating piston moves downwards to the upper part of the packing device for fitting, the packing device starts to act along with the increase of the pressure difference between the upper surface and the lower surface to a set value, the annular space between the drill rod and the inner sleeve is closed, and fluid in the well is prevented from jumping upwards along the annular space between the drill rod and the inner sleeve. When the pressure difference between the upper part and the lower part of a floating piston in the annulus between the inner sleeve and the outer sleeve exceeds a set value, the floating piston moves downwards to press the upper end surface of the packing device to move downwards, the inclined surface pushes a lever to drive a packing slide block to contract inwards to seal the annulus between the drill rod and the inner sleeve, and the packing slide block is locked by an inclined surface clamping groove arranged at the upper part of the packing device to ensure that the annulus between the drill rod and the inner sleeve is reliably packed. When the pressure of the well killing fluid in the well killing pipeline is increased to exceed the fluid pressure of a shaft, the floating piston moves downwards to press the packing device, the pressure is continuously increased, the floating piston is sheared under the action of the vertical pressure difference of the floating piston, a channel for the well killing fluid to enter the shaft is established, the specific gravity of the well killing fluid is adjusted, and well killing is achieved.

The utility model discloses it is heavy in the difficult problem of solving no marine riser mud and lifting drilling system and can't adopt heavy thick liquid kill-job, in addition, still can realize closing the well when taking place serious kick or blowout out of control, be used for simultaneously no marine riser mud to lift the auxiliary control that realizes the interior mud liquid level of seabed Suction Module (SMO) when drilling system operation, use this utility model discloses the device is equivalent to and applys an additional pressure in seabed well head position, strengthen the two gradient effects of deep water, make SMD be applied to the lower part well section outside the deep water top layer and even the deep drilling of whole well become probably. The utility model discloses not only can be used to the deepwater does not have riser mud and lifts drilling system, the kill job to conventional ocean drilling and shallow sea, mud flat and even land drilling all has great using value.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all the modifications and modifications of the technical entity of the present invention, which are simple to implement, are within the scope of the technical solution of the present invention.

Claims

1. A subsea wellhead assembly, characterized by: comprises an outer sleeve, an inner sleeve, a floating piston and a packing device; the well killing device comprises an outer sleeve, an inner sleeve, a floating piston, a packer, a well killing liquid, a drilling rod, a suction module and a subsea pump, wherein the outer sleeve is consolidated with surrounding strata through cement and used for fixing a wellhead device and supporting the weight of the whole well killing device; the floating piston is able to slide up and down along the inner sleeve.