CN106640030B - Asymmetric online installation method of underwater three-stage separation system - Google Patents

Abstract

The invention provides an asymmetric online installation device and method for an underwater three-stage separation system, which are applied to rapid butt joint and online installation of the underwater separation system. The air cell body of the online installation device adopts asymmetric double air cells, the follow-up drifting is completed according to the spherical deviation adjusting mechanism, the horizontal deviation of the installation device is automatically adjusted, the vertical displacement is automatically adjusted according to the balance action of the air cell body and the balance pipe, and therefore stable hoisting is achieved; the connecting rigging and the upper and lower hoisting bases respectively complete three-point hoisting, prying and neutralizing support of the underwater three-stage separator; three groups of catching cylinders and traction pipes are arranged on a hoisting base in a three-point mode to form a three-cylinder automatic centering mechanism, the catching cylinders are matched with the traction pipes to realize automatic centering in hoisting and centering operations, and a locking mechanism is arranged in the catching cylinders to realize automatic locking in the centering operations; the asymmetric online installation method is characterized in that a whole set of operation process is implemented by depending on an installation device, and online rapid installation of the underwater separation system is completed.

Description

Asymmetric online installation method of underwater three-stage separation system

technical field

The invention relates to a device and method for installing an underwater separation system in the field of marine engineering, in particular to an asymmetric online installation device dedicated to an underwater three-stage separation system and its installation process.

Background technique

The production mode of subsea production system plus floating platform has become one of the most important modes of deep sea oil and gas development. The subsea production system generally consists of subsea wellheads, Christmas trees, production/separation equipment, jumper pipes, subsea pipelines, etc. Composition of production equipment, the use of underwater separation equipment can move the crude oil and production sewage treatment equipment from the offshore platform block to the underwater system, which greatly simplifies the crude oil and production sewage treatment process, and effectively solves the problem of large footprint and weight of conventional technical equipment However, it also poses challenges to the installation of underwater production systems.

At present, foreign countries have developed multi-functional ships and corresponding installation devices for installing deep-water equipment, and have carried out preliminary applications in relevant offshore projects. However, my country started relatively late in the installation of deep-water equipment, and there is no deep-water equipment with mature technology. Equipment installation ships and special installation devices. The installation of underwater equipment still adopts the conventional shallow sea installation operation method. The installation operation process is usually divided into four stages. The underwater equipment is only affected by the wind load. The second stage is the submerged operation of the underwater equipment, while the third stage is the complete submerged operation stage. During this process, the underwater equipment will be affected by loads such as wave force and ocean current force. The fourth stage For setting and connecting operations, this process is mainly affected by environmental factors.

It can be seen that the stress situation during the installation process of underwater equipment is extremely complicated. During the entire installation period, the equipment will be affected by loads such as wind force, wave force and ocean current force, and at the same time be affected by the movement of the installation ship. Therefore, conventional shallow sea installation devices and The operation method is no longer suitable for the installation of underwater equipment in deepwater oil and gas fields, and it is necessary to develop special installation equipment for deepwater systems in order to ensure the safety of deepwater development and construction operations and the integrity of equipment structures, as well as ensure installation accuracy and underwater separation equipment. Can be installed quickly and smoothly into the correct position.

Contents of the invention

In order to effectively solve the installation problem of the underwater separation system and overcome the defects and deficiencies existing in the existing shallow sea installation technology and operation mode, the purpose of the present invention is to provide an asymmetrical separation system suitable for the installation of the underwater three-stage separation system for the development of deep water oil and gas fields. An online installation device and an installation method thereof. Based on the follow-up drift of the asymmetric cell body on both sides of the balance tube, the balance effect of the balance tube and the cell body, the three-point hoisting of the connecting rigging, and the automatic centering and locking mechanism of the three tubes between the capture tube and the traction tube, the Stable hoisting, automatic centering and locking of the underwater three-stage separation system, as well as quick docking and online installation with the underwater manifold and submarine pipeline.

The technical solution adopted by the present invention to solve the technical problem is to provide an asymmetric online installation method for an underwater three-stage separation system. , hoisting base, capture tube and traction tube, its overall design adopts an asymmetric structure, in which the cell body, hoisting rigging, connecting rigging, capture tube and traction tube are arranged vertically, while the balance tube and hoisting The base adopts the form of horizontal arrangement.

The air cell body adopts an asymmetric double air cell structure, and there is a slightly positive pressure gas stored in the air cell body, and the follow-up drift is completed according to the spherical deflection adjustment mechanism, so as to balance the random load of wave force and the internal wave force of the ocean current in hoisting and centering operations Random load, automatically adjust the offset of the installation device in the horizontal direction, and at the same time, according to the asymmetric balance effect of the air cell body, balance the vertical oscillation load transmitted by the wave and the internal wave of the ocean current through the hoisting rigging, and automatically adjust the vertical vibration load of the installation device. To ensure the stable hoisting of the underwater three-stage separation system. The air cell body includes small air cells, large cells, exhaust valves, deflection adjustment spheres, deflection adjustment cover and deviation adjustment body, among which the materials of small air cells, large cells and deflection adjustment spheres are made of polyester with high strength and strong cold and heat stability After the diagonal cord fabric is compounded with seawater-resistant rubber, it is vulcanized by high-pressure and high-temperature molds. The material of the bias adjustment cover and the deviation adjustment body is made of super duplex stainless steel, and the whole body is coated with glass glue. Each part of the cell body adopts a split structure. The exhaust valve, the deflection adjustment sphere, the deflection adjustment cover and the deviation adjustment body all contain two monomers with the same structure on the left and right, and correspond to the small air cell and the large cell respectively. And the axes between the left and right deviation adjustment pressure covers and the deviation adjustment body are kept parallel.

The asymmetric double air cells used in the air cell body include small air cells and large air cells. Both small air cells and large air cells are inverted conical air cells, and both are composed of upper spheres and lower cones. The upper spheres of the small air cells and large air cells are It adopts a hemispherical structure, and the top of the upper sphere is provided with a cylindrical boss. The center of the cylindrical boss is processed with a sealing pipe threaded hole, and an exhaust valve is configured. Cells filled with small and large cells provide channels. The lower cones of the small air cells and large cells adopt an inverted cone structure, and the large end circular surface of the upper part of the lower cone is kept tangent to the lower end surface of the upper sphere, while the diameter of the small end circular surface of the lower part is equal to that of the deflection sphere The outer diameter of the upper disc body section.

The spherical deflection adjustment mechanism of the air cell body is composed of a deflection adjustment sphere, a deflection adjustment cover and a deflection adjustment body. A spherical pair is used between the deflection adjustment sphere, the deflection adjustment gland and the deflection adjustment body. The load and deflection adjustment sphere adjust the angle by itself and complete the follow-up drift of the small air cell and the large air cell, so as to achieve the purpose of adjusting the horizontal offset of the installation device.

The deviation adjustment body adopts a cylinder, the lower part of which is connected with the balance pipe through a flange, and the central part of the upper end surface of the deviation adjustment body is processed with a semicircular spherical surface, and the center of the semicircular spherical surface of the deviation adjustment body is located on the axis of the deviation adjustment body; There is an annular groove milled on the lower end surface of the flange of the deviation adjustment body. The cross section of the annular groove is isosceles trapezoidal, and a hexagonal metal ring is arranged inside. The hexagonal metal ring adopts a thick metal ring body, and its metal The ring body is made of metal with high strength and high temperature resistance, and the outside of the metal ring body is wrapped with metal foil.

The outer ring surface of the bias adjustment cover is conical and cylindrical from top to bottom, while the central part of the upper end surface is drilled with an inverted conical surface. At the same time, its taper is greater than the deflection adjustment angle of the air cell body; and the cavity wall of the deflection adjustment cover at the lower end of the inverted conical surface is processed with a hemispherical surface, and the hemispherical surface of the deflection adjustment cover is equal to the hemispherical surface of the deflection adjustment body. Precise grinding is carried out, and the two semi-spherical surfaces are always kept concentric. At the same time, the lower cavity wall of the semi-spherical surface of the bias adjustment cover is lined with a tubular pressure sleeve. The gland is connected with the deviation adjusting body.

The upper part of the deflection adjustment sphere is connected with the small air cell and the large air cell respectively through the disc body, and the middle part of the deflection adjustment sphere adopts an inverted cone and a cylinder from top to bottom, and the taper of the deflection adjustment sphere is equal to the deviation adjustment pressure Cover the taper of the conical surface; the lower part of the deviation adjustment sphere adopts a spherical surface, which is always concentric with the semicircular surface of the deviation adjustment pressure cover and the deviation adjustment body, and adopts a clearance fit to form a spherical pair to ensure that the deviation adjustment sphere The degree of freedom and flexibility in the deviation adjustment cover and the deviation adjustment body; the lower end of the deviation adjustment sphere is cut with a cut surface parallel to the end surface of the upper disc body, and the cavity wall at the center of the cut surface adopts a structure combining conical surface and cylindrical surface , in order to improve the stress adjustment inside the sphere. The spherical surface of the deflection adjustment sphere is provided with annular grooves arranged in layers at equal intervals from top to bottom, and there are four layers in total. The apex of the cone surface is concentric with the center of the spherical surface of the deflection adjusting sphere, and the cross-section of each layer of annular grooves is rectangular, filled with lubricating grease. The semi-spherical surface cooperates, and the lower two layers of annular grooves cooperate with the semi-spherical surface of the deviation adjustment body.

The balance pipe adopts a horizontal long pipe structure, connecting the air cell body and hoisting rigging at the top and connecting the rigging at the bottom. At the same time, the balance pipe stores gas under a slight positive pressure and assists the air cell body to balance the waves and ocean currents during hoisting, centering and docking operations The vertical oscillation load transmitted by the internal wave through the hoisting rigging. The balance pipe includes the base pipe body, the hanging seat and the middle support. The material of the balance pipe is super duplex stainless steel, and the whole body is coated with glass glue.

The two sides of the base pipe body are respectively provided with flanges, and each flange is equipped with a blind end flange on the outside, so that the base pipe body is divided into independent airtight chambers. Each flange and the blind end method There are annular grooves of the same size on the end faces of the flanges combined, and the two annular grooves on the flange and the blind flange are symmetrically arranged to form an annular cavity, which is equipped with a hexagonal Metal rings, so as to realize the sealing of both ends of the base pipe body. The left and right sides of the base pipe body are respectively provided with three-way pipes, and the left and right side three-way pipes are arranged in an asymmetrical vertical manner, and their axes coincide with the axes of the deviation adjustment cover and the deviation adjustment body respectively. The axial position on the base pipe body is determined according to the center of gravity position of the left and right sides of the underwater three-stage separator; the upper ends of the left and right tee pipes are provided with flanges, and are connected by double-ended studs and the deflection adjustment body. Lan disk to connect. The upper end faces of the left and right tee pipe flanges are processed with annular grooves of the same size as the flanges of the deviation adjustment body, and the annular grooves on the left and right tee pipe flanges and the deviation adjustment body flanges The central cylindrical surfaces formed by the central symmetry lines of the section of the upper annular groove keep coincident with each other.

Both the hanging seat and the middle support are vertically arranged, and the hanging seat is symmetrically arranged on both sides of the upper pipe body of the base pipe body and is located between the left and right tee pipes. The hanging seat is divided into two groups, and the middle support adopts Arranged asymmetrically on the lower pipe body of the base pipe body, the middle supports are divided into three groups, the middle supports of the left and right groups are located directly under the left and right tee pipes, and the positions of the middle group of supports are based on It depends on the axis of the first stage separator in the underwater three-stage separator. Each set of hanging base and middle support contains two monomers and the two monomers are placed in parallel. The structure and specifications of the two monomers of each set of hanging base and middle support are the same and are composed of semicircular steel plates and rectangular steel plates. , the diameter of the hole in the center of the semicircular steel plate is equal, and the upper suspension seat cooperates with each upper pin shaft to realize the hinge connection between the hoisting rigging and the balance pipe, and at the same time, the middle support bracket cooperates with each middle pin shaft to realize the connection between the rigging and the balance pipe. Balance the joints between the tubes.

The hoisting sling is used to complete the hoisting of the entire installation device and the underwater three-stage separator. It consists of a main hoisting rope and two sub-hoisting ropes. The lifting rope is located on the central symmetrical plane of the balance pipe and connected upward to the crane hook of the construction ship on the sea surface. The lengths of the two hanging ropes are equal and symmetrically arranged on both sides of the main lifting rope and then connected to the upper hanging seat.

The connecting rigging is used to complete the connection between the entire installation device and the underwater three-stage separator, and realize the three-point hoisting of the underwater three-stage separator. It is composed of three connecting ropes and three sets of lower supports. The three connecting ropes are It is vertically arranged and its length is determined according to the position of each interface of the underwater three-stage separator, and at the same time, the two ends of each connecting rope are respectively connected to the middle support and the lower support.

The main and sub-slings of the hoisting sling and the connecting ropes of the rigging are of the same structural form, and the main and sub-suspensions and the connecting ropes are all composed of rope joints, connecting pipes and rope bodies. The configuration of the main sling is One connecting pipe and rope body, and each sub-sling is equipped with a rope joint, connecting pipe and rope body, and each connecting rope is equipped with two rope joints, connecting pipes and a rope body, and the two connecting ropes The rope joint and the connecting pipe are symmetrically arranged at both ends of the rope body of the connecting rope and connected as a whole. One end of the rope joint is composed of a half cylinder and a square, while the other end uses a variable-section shaft and is connected with the connecting pipe through a sealing pipe thread; the connecting pipe adopts a long pipe body, and its inner wall A stepped turning surface is used to fix the rope end of the rope body.

The lower supports connecting the rigging are vertically arranged and correspond to the middle supports one by one. Each group of lower supports is spliced by two parallel side plates and a horizontally placed flange. The lower supports The structure and specifications of the two side plates are the same as the upper suspension seat and the middle support, and the flange plate of the lower support is connected with the flange plate at each interface of the skid body of the underwater three-stage separator through double-ended studs , the lower bearings cooperate with the lower pins respectively to realize the hinge between the connecting rigging and the underwater three-stage separator.

The hoisting base is spliced by channel steel and I-beam. The structure and specifications of the upper hoisting base and the lower hoisting base are the same. The upper hoisting base is used to complete the prying and hoisting of the underwater three-stage separator, while the lower hoisting base is It is connected with the subsea oil tree and the subsea manifold and is used to complete the centering and support of the subsea tertiary separator. The overall outline of the hoisting base presents a ship-like shape. The main "ship" body in the middle of the hoisting base is rectangular and an underwater three-stage separator is arranged on it. The "ship" bow on the left side of the hoisting base is isosceles trapezoidal and a group of The stern of the "boat" on the right side of the hoisting base is rectangular, and two sets of catching tubes and towing tubes are symmetrically arranged on both sides, so three sets of catching tubes and towing tubes are arranged in three points on the hoisting base. Three cylinder automatic centering mechanism.

The catching cylinder adopts three vertical thick-walled cylinders, which are respectively arranged on the upper hoisting base. The catching cylinder cooperates with the traction tube to realize the automatic centering of the three cylinders in the hoisting and centering operation. The catching cylinder is equipped with a uniformly arranged locking mechanism To realize the automatic locking in the centering operation, it includes the capture base cylinder, lock pin and lock spring. The material of the capture base cylinder is super duplex stainless steel, and the whole body is coated with glass glue. The material of the lock pin is 35CrMo and quenched and tempered. processing, and the material of the lock spring is 65Mn.

The catching base cylinder adopts a combination of cylinder and cone, and its lower end surface is flush with the bottom end of the upper hoisting base. into a cylindrical surface, and the upper and lower ends of the cylindrical surface are respectively drilled into conical surfaces to capture the diameter of the small end circular surface of the upper conical surface of the inner wall of the base cylinder, the diameters of the middle cylindrical surface and the small end circular surface of the lower conical surface are equal, and at the same time The taper and cone height of the conical surface at the upper end of the inner cylinder wall are smaller than the taper and cone height of the conical surface at the lower end of the inner cylinder wall. The middle wall of the catch base cylinder is drilled with cylindrical blind holes evenly arranged along the circumference, and the bottom of each cylindrical blind hole is processed with a variable-section positioning shaft. The positioning shaft adopts a stepped shaft structure, and the cross-section of the positioning shaft The change forms a shoulder to locate the side end of the lock spring extending therethrough.

A locking mechanism consisting of a lock pin and a lock spring is arranged in the cylindrical blind hole on the middle wall of the catch base cylinder. The wall is precisely matched to form a moving pair. The inner end surface of the lock pin is provided with a wedge-shaped groove, and the wedge-shaped groove is arranged downward; the section change of the outer end surface of the lock pin forms a shaft shoulder to locate the other side of the lock spring that runs through it. At the side end, through the telescopic movement of the lock spring, the lock pin is driven to slide inside and outside to realize the automatic locking between the catch cylinder and the traction tube.

The traction pipe adopts three vertical long pipe bodies, which are respectively arranged on the lower hoisting base, and the automatic centering in the hoisting and centering operation is realized by pulling the catch cylinder, which includes the traction base pipe and the support pipe, the traction base pipe and the support The material of the tube is made of super duplex stainless steel, and the whole body is coated with glass glue. The overall outline of the traction tube is rocket-like. The traction base tube is welded by a conical tube and a column tube, and its lower end is welded with a disc-shaped steel plate. The bottom end of the disc-shaped steel plate is flush with the bottom of the lower hoisting base. The taper of the tapered surface of the outer wall of the tapered pipe in the pipe is consistent with the inclination of the wedge-shaped groove on the lock pin, and the diameter of the tapered surface of the outer wall of the tapered pipe in the traction base pipe is the same as the outer diameter of the column pipe in the traction base pipe They are equal to the diameter of the cylindrical surface in the middle of the inner wall of the capture base tube. The middle part of the column tube of the traction base tube is drilled with circular holes that match the locking mechanism of the capture tube. The hole walls of each circular hole and the outer ring surface of the lock pin Use clearance fit. The support pipe adopts a tapered pipe, and the taper of the outer wall of the tapered pipe in the support pipe is equal to the taper of the lower end of the inner cylinder wall of the base cylinder, and is greater than the taper of the outer wall of the tapered pipe in the traction base pipe; in addition, the support pipe Both the upper and lower ends of the traction base pipe and support pipe are fixed on the lower hoisting base by means of circumferential welding.

The asymmetric online installation method of the underwater three-stage separation system relies on the asymmetric online installation device to implement the following complete set of operations in sequence: underwater manifold measurement and positioning operations, separation system hoisting operations, asymmetric centering operations, air cell The recovery operation of the balance pipe and the docking operation of the separation system complete the online rapid installation of the underwater three-stage separation system.

The process of subsea manifold measurement and positioning operation is to accurately determine the relative position between the subsea tree, subsea manifold and sub-hoisting base, including three-dimensional coordinates and spatial azimuth, etc. The spatial coordinates of each interface of the lower manifold and the traction pipes arranged on the lower hoisting base, and the corresponding hoisting operation plan are formulated according to the underwater measurement parameters.

The process of hoisting the separation system is to open the exhaust valve to fill the small and large cells of the cell body and the base pipe body of the balance pipe with gas at a slight positive pressure in sequence, and then move the cell body, hoisting rigging and connecting rigging through the balance tube. connected as a whole, and then each capture tube is prefabricated on the upper hoisting base, and the underwater three-stage separator is completed through the upper hoisting base, and then the underwater three-stage separator is connected to the At the lower part of the air cell body and the balance pipe, the three-point hoisting of the connecting rigging is realized; finally, according to the measured relative position parameters of the underwater manifold and the lower hoisting base, the underwater third-stage is lowered through the crane and hoisting rigging on the construction ship. Separator, in the process of hoisting and lowering, the underwater three-stage separator is smoothly and stably hoisted to the interface position of the underwater manifold according to the moving drift of the asymmetric air cell body and the balance between the balance tube and the air cell body.

The process of the asymmetrical centering operation is to balance the random load of wave force and the random load of internal wave force of the ocean current according to the follow-up drift of the asymmetric air cell body in the centering operation, and automatically adjust the horizontal position of the underwater three-stage separator. At the same time, the vertical oscillation load is balanced according to the asymmetrical balance effect of the cell body and the balance tube, and the vertical displacement of the underwater three-stage separator is automatically adjusted; then, the underwater robot, the capture cylinder and the traction tube are used The three-cylinder automatic centering mechanism in the middle realizes the automatic centering between the underwater three-stage separator and the upper hoisting base and the lower hoisting base; finally, continue to hoist and lower the underwater three-stage separator, according to the lock configured in the capture base cylinder The lock pin of the tightening mechanism cooperates with the circular hole on the traction base pipe to realize the automatic locking between the underwater three-stage separator and the upper hoisting base and the lower hoisting base.

The process of recovering the cell balance pipe is to use the underwater robot to open the exhaust valve to fill the small cells and large cells of the cell body with seawater in sequence, and then close the exhaust valve; then, use the underwater robot to unscrew the connecting rigging The double-headed studs on the support, according to the balance of the balance pipe, remove the connecting rigging from each interface of the underwater three-stage separator skid body through the crane and hoisting rigging, and recover it to the construction ship.

The process of the docking operation of the separation system is to stably hoist the connecting oil pipe to the lower end of the oil-gas collection pipe of the underwater three-stage separator through the crane, hoisting rigging and connecting rigging according to the balancing effect of the balancing pipe, and use the underwater The robot and the connecting oil pipe connect the underwater oil delivery pipe to the underwater three-stage separator; then, stably hoist the connecting water pipe to the interface at the lower end of the underwater three-stage separator drainage pipe, and use the underwater robot and the connecting water pipe to connect the underwater water delivery pipe to the third-stage underwater separator. It is integrated with the underwater third-stage separator; finally, according to the balance of the balance pipe, the jumper oil pipe is stably hoisted to the position between the underwater manifold interface and the inlet of the underwater third-stage separator, and the underwater robot and the cross-over The oil connection pipe connects the subsea three-stage separator to the subsea oil tree and the subsea manifold, so that the subsea oil and gas well output fluid can be directly separated from oil, gas and water and treated with oily sewage under water.

The technical effect that the present invention can achieve is that the asymmetric online installation device is based on the follow-up drift effect of the asymmetric air cell body, the balance effect of the balance pipe and the air cell body, the three-point hoisting of the connecting rigging and the gap between the catch tube and the traction pipe. The advanced three-cylinder automatic centering and locking mechanism realizes the stable hoisting, automatic centering and locking of the underwater three-stage separation system, as well as the rapid docking and online installation with the underwater manifold and submarine pipeline; Symmetrical double air cells, complete the follow-up drift based on the spherical deflection adjustment mechanism, automatically adjust the horizontal offset of the installation device, and automatically adjust the vertical displacement according to the balance between the air cell body and the balance tube to ensure the underwater three-stage separation Stable hoisting of the system; connect the rigging to complete the three-point hoisting of the underwater three-stage separator, the upper hoisting base completes the prying and hoisting of the underwater three-stage separator, and the lower hoisting base completes the centering of the underwater three-stage separator and support; three sets of catch tubes and traction tubes are arranged in three points on the hoisting base to form a three-tube automatic centering mechanism. There are evenly arranged locking mechanisms to realize automatic locking in the centering operation; the asymmetric online installation method is to rely on the installation device to carry out the underwater manifold measurement and positioning operation, the separation system hoisting operation, and the asymmetrical alignment operation in sequence , The whole set of operation process of cell balance tube recovery operation and separation system docking operation, complete the online rapid installation of underwater separation system.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

Fig. 1 is a typical structural diagram of an asymmetric online installation device for an underwater three-stage separation system proposed according to the present invention.

Fig. 2 is a schematic diagram of the structure of the gas cell body in the asymmetric online installation device of the underwater three-stage separation system.

Fig. 3 is a schematic diagram of the structure of the balance pipe, hoisting rigging and connecting rigging in the asymmetric online installation device of the underwater three-stage separation system.

Fig. 4 is a schematic diagram of the structure of the capture cylinder and the upper hoisting base in the asymmetric online installation device of the underwater three-stage separation system.

Fig. 5 is a schematic diagram of the structure of the traction pipe and the lower hoisting base in the asymmetric online installation device of the underwater three-stage separation system.

FIG. 6 is a top view of FIG. 5 .

Fig. 7 is a schematic flow chart of the separation system hoisting operation in the asymmetric online installation method of the underwater three-stage separation system.

Fig. 8 is a schematic flow chart of the asymmetrical centering operation in the asymmetrical on-line installation method of the underwater three-stage separation system.

Fig. 9 is a schematic flow chart of the recovery operation of the air cell balance tube in the asymmetric online installation method of the underwater three-stage separation system.

Fig. 10 is a schematic flow chart of the docking operation of the separation system in the asymmetric online installation method of the underwater three-stage separation system.

In the figure, 1-hoisting rigging, 2-air cell body, 3-balance pipe, 4-connecting rigging, 5-underwater three-stage separator, 6-hoisting base, 7-capturing cylinder, 8-traction pipe, 9- Small air cell, 10-exhaust valve, 11-large cell, 12-bias adjustment ball, 13-bias adjustment cover, 14-bias adjustment body, 15-main sling, 16-separate sling, 17-upper pin , 18-hanging seat, 19-base pipe body, 20-middle support, 21-middle pin, 22-connecting rope, 23-lower pin, 24-lower support, 25-capture base cylinder, 26-lock Spring, 27 - locking pin, 28 - upper hoisting base, 29 - support pipe, 30 - traction base pipe, 31 - lower hoisting base, 32 - subsea tree, 33 - subsea manifold, 34 - jumper tubing, 35-pipe hanger, 36-connect oil pipe, 37-underwater oil pipeline, 38-connect water pipe, 39-underwater water pipeline.

detailed description

In Fig. 1, the asymmetric online installation device of the underwater three-stage separation system is mainly composed of hoisting rigging 1, air cell body 2, balance pipe 3, connecting rigging 4, hoisting base 6, capture cylinder 7 and traction pipe 8, Its asymmetric online installation method is to carry out the whole set of operation process of underwater manifold measurement and positioning operation, separation system hoisting operation, asymmetric centering operation, air cell balance pipe recovery operation and separation system docking operation in sequence, thus completing On-line rapid installation of underwater three-stage separator 5.

In Fig. 1, before the assembly of the asymmetric online installation device, the outer surfaces of the main parts of the hoisting rigging 1 and the connecting rigging 4 are respectively coated with grease to prevent seawater corrosion, and the outer surfaces of the main parts of the hoisting base 6 are sprayed for corrosion protection deal with. When the asymmetric online installation device is assembled, firstly, the hoisting sling 1 is passed through the upper pin shaft and the connecting sling 4 is connected with the balance pipe 3 through the middle pin shaft in sequence, and then the small air cell and the large cell of the cell body 2 are passed through The deflection adjustment body is connected to both sides of the balance pipe 3, and then the underwater three-stage separator 5 is skidded through the upper hoisting base of the hoisting base 6 and connected to the lower end of the connecting rigging 4 through the lower pin to realize three-point hoisting, and the last three sets of catch tubes 7 and traction pipe 8 are arranged in three points on the hoisting base 6 to form a three-cylinder automatic centering mechanism, and the lower hoisting base of the hoisting base 6 is connected with the traction pipe 8 with the subsea tree and the subsea manifold.

In Figure 1, when the asymmetric online installation device is being debugged, the spherical surface of the deflection adjustment sphere of the air cell body 2 and the semicircular surface of the deflection adjustment cover and the deviation adjustment body can flexibly rotate in all directions in space without any blockage. The lock pin in the locking mechanism of the capture cylinder 7 and the circular hole of the traction base pipe in the traction tube 8 can slide flexibly without obstruction, and keep the air cell body 2, the balance pipe 3 and the inner wall of the underwater three-stage separator 5 At the same time, check whether the valves of the gas cell body 2 exhaust valve and the underwater three-stage separator 5 underwater safety valve, underwater control valve, and underwater shut-off valve are switched correctly, and check whether the adjustment in the gas cell body 2 is correct. Check whether the annular grooves of each layer of the sphere are filled with lubricating grease, check whether the lock pin in the locking mechanism of the catch cylinder 7 is damaged, and whether there are scratches on the semicircular surface of the bias adjustment cover and the deviation adjustment body in the air cell body 2. Whether the pin shafts and threaded joints are firm and free of rust.

In Fig. 1, the hoisting rigging 1, air cell body 2, connecting rigging 4, capture cylinder 7 and traction pipe 8 in the asymmetric online installation device are all vertically arranged, while the balance pipe 3 and the hoisting base 6 are arranged vertically. The horizontal layout is adopted, and the installation operation is based on the follow-up drift of the asymmetric cell body 2, the balance effect of the balance tube 3 and the cell body 2, the three-point hoisting of the connecting rigging 4, and the three tubes between the catch tube 7 and the traction tube 8 The automatic centering and locking mechanism completes the stable hoisting, automatic centering and locking of the underwater three-stage separator 5, as well as its rapid docking and online installation with the underwater manifold and submarine pipeline.

In Fig. 2, the air cell volumes of the small air cells 9 and the large air cells 11 are determined according to the random load of wave force in the sea area where hoisting and centering operations are performed, the random load of wave force in the ocean current, the vertical oscillation load transmitted by the hoisting rigging 1, and the water load. The lower three-stage separator 5 is selected comprehensively based on factors such as the total weight concentrated on the left and right sides. At the same time, the specifications of the exhaust valve 10 are selected according to the cell volumes of the small cell 9 and the large cell 11 respectively. The angle between the bias adjustment cover 13 and the deviation adjustment body 14 in space in all directions is designed according to the actual working conditions of the random load of wave force in the sea area where the hoisting and centering operations are performed and the random load of wave force in the ocean current.

In Fig. 2, the small air cells 9 and the large air cells 11 are arranged asymmetrically on both sides of the balance pipe 3 according to the total weight concentrated on the left and right sides of the underwater three-stage separator 5 and form corresponding floating loads for balance, thus Automatically adjust the vertical displacement of the installation device; the spherical deviation adjustment mechanism is formed by connecting the deviation adjustment sphere 12 with the deviation adjustment pressure cover 13 and the deviation adjustment body 14, thereby realizing the follow-up drift of the air cell body 2 and The offset in the horizontal direction of the installation device is automatically adjusted to complete the stable hoisting of the underwater three-stage separator 5; in addition, the small air cell 9 and the large air cell 11 can be filled with slightly positive pressure gas and seawater through the exhaust valve 10.

In Figure 3, the volume of the base pipe body 19 in the balance pipe 3 is comprehensively selected based on factors such as the sea conditions in the sea area where the hoisting and centering operations are performed, the vertical oscillation load transmitted by the hoisting rigging 1, and the required maximum floating load. , the selection of the length of the base pipe body 19 needs to consider the total size of the underwater three-stage separator 5 into the pry body; The sea conditions of the sea area and the maximum hook load required for hoisting the underwater three-stage separator 5 shall be designed, while the specifications and dimensions of the connecting rope 22 in the connecting sling 4 need to consider the sea conditions of the sea area where hoisting, centering and recovery operations are performed, as well as hoisting The maximum tensile stress required for the underwater three-stage separator 5 and the crossover tubing is selected.

In Fig. 3, the base pipe body 19 stores a slightly positive pressure gas, thereby realizing the balance of the balance pipe 3 and assisting the air cell body 2 to balance the vertical oscillation load in hoisting, centering and docking operations; the base pipe body 19 passes through The upper hanging seat 18 on the outer ring surface cooperates with the upper pin shaft 17 to connect the suspension rope 16, and through the cooperation between the middle support 20 and the middle pin shaft 21, the connecting rope 22 is connected downward, while the main suspension rope 15 is connected with the crane on the construction ship, and the connecting rope 22 realizes the connection between the online installation device and the underwater three-stage separator 5 through the cooperation between the lower pin shaft 23 and the lower support 24.

In Fig. 4, the specifications and dimensions of the upper hoisting base 28 of the hoisting base 6 are adjusted according to the total size of the pry body of the underwater three-stage separator 5. In the three-stage separator 5, the layout orientation of the separators at all levels is determined; in the capture cylinder 7, a locking mechanism composed of a lock pin 27 and a lock spring 26 is configured in the cylindrical blind hole on the cylinder wall of the capture base cylinder 25, and the locking mechanism is locked. The mechanisms are evenly arranged along the circumferential direction, and the telescopic movement of the lock spring 26 drives the lock pin 27 to slide inside and outside, so as to realize the automatic locking between the catch tube 7 and the traction tube 8 during the centering operation.

In Fig. 5 and Fig. 6, the structure and specifications of the lower hoisting base 31 of the hoisting base 6 are consistent with the upper hoisting base 28, and the support tubes 29 of the three sets of traction tubes 8, the traction base tube 30 and the catch tube 7 are hoisted at the bottom respectively. The base 31 and the upper hoisting base 28 are arranged in three points to form a three-cylinder automatic centering mechanism. The three-cylinder automatic centering mechanism captures the positions of the base tube 25 and the traction base tube 30 in one-to-one correspondence and realizes hoisting and centering through cooperation The three cylinders in the operation are automatically centered.

In Fig. 7, in the separation system hoisting operation process, the small air cell 9, the large cell 11 and the base pipe body 19 are respectively filled with slightly positive pressure gas and connected together by flanges and studs, the base pipe body 19 The main suspension rope 15 and the sub-suspension rope 16 are connected upward through the upper suspension base 18 and the connecting rope 22 is connected downward through the middle support 20. Pry, and connect with the online installation device through the lower support 24 and realize three-point hoisting. During the hoisting process, the underwater three-stage separator 5 is gradually lowered by continuously releasing the main suspension rope 15, and the random load of the wave force and the random load of the internal wave force of the ocean current are balanced in real time by using the follow-up drift of the asymmetric cell body 2, while using the balance The balancing action of the tube 3 and the cell body 2 balances the vertical oscillation load in real time, so that the underwater three-stage separator 5 is hoisted smoothly and stably to the interface of the underwater manifold.

In Fig. 8, in the asymmetrical centering operation process, the random load of wave force and the random load of internal wave force of ocean current are balanced in real time by the follow-up drift of the asymmetric air cell body 2, and the underwater three-stage separator 5 is automatically adjusted in The horizontal offset θ ₁ on the side of the small cell 9 and the horizontal offset θ ₂ on the side of the large cell 11 are used to balance the vertical oscillation load in real time by using the balance of the balance tube 3 and the cell body 2, and automatically adjust the underwater three-stage The vertical displacement of the separator 5, so as to maintain the stability of the underwater three-stage separator 5 in operation; then, use the underwater robot to automatically align each capture base tube 25 with the traction base tube 30 at the corresponding position, and continue to go underground smoothly Put the three-stage separator 5 under the water, and after the lock pin 27 of the locking mechanism in the base tube 25 is pushed and slid into the circular hole of the traction base tube 30 pipe wall by the lock spring 26, the catch tube 7 and the traction tube 8 are automatically closed. Locking, thereby the underwater three-stage separator 5 is fixed on the hoisting base 6 of the seabed.

In Fig. 9, in the air cell balance pipe recovery operation process, the underwater robot is first used to open the exhaust valve 10 and fill the small air cell 9 and the large cell 11 with seawater to remove the floating load of the air cell body 2; then, use The underwater robot unscrews and pulls out the studs on each lower support 24 in sequence, and disassembles the underwater three-stage separator 5 from the online installation device; 2. The balance pipe 3 and the connecting rigging 4 are recovered to the construction ship together.

In Fig. 10, in the docking operation process of the separation system, a new hoisting device is composed of hoisting rigging 1, balance pipe 3 and connecting rigging 4, and the hoisting operation is carried out by using the balancing function of the balance pipe 3. First, the connecting oil pipe 36 is stably hoisted To the interface at the lower end of the oil and gas collection pipeline of the underwater three-stage separator 5, use an underwater robot to tighten each stud to connect the connecting oil pipe 36 and the underwater oil delivery pipe 37 to the underwater three-stage separator 5; then, use The new hoisting device will stably hoist the connecting water pipe 38 to the interface at the lower end of the underwater three-stage separator 5 drainage pipe, and use the underwater robot to tighten the studs to sequentially connect the connecting water pipe 38 and the underwater water delivery pipe 39 to the underwater On the three-stage separator 5; finally, connect the jumper oil pipe 34 to the new hoisting device through the cooperation of the pipe hanger 35 and the lower pin shaft 23, and stably hoist it to the interface of the underwater manifold 33 and the underwater three-stage separator 5 In the position between the inlets, use the underwater robot to tighten the studs to connect one end of the jumper oil pipe 34 to the underwater Christmas tree 32 and the underwater manifold 33, and at the same time, connect the other end of the jumper oil pipe 34 to the underwater three The stage separators 5 are connected together, and then use the underwater robot to pull out the lower pins 23 to disassemble the new hoisting device from the jumper oil pipe 34, and recover the new hoisting device through the crane and hoisting rigging 1 to the construction ship.

Above-mentioned each embodiment is only for illustrating the present invention, wherein the structure of each component, connection mode etc. all can be changed to some extent, every equivalent conversion and improvement carried out on the basis of the technical solution of the present invention, all should not be excluded from the present invention. outside the scope of protection of the invention.

Claims (10)

1. An asymmetric online installation method of an underwater three-stage separation system is based on an asymmetric online installation device of the underwater three-stage separation system, and realizes stable hoisting, automatic centering and locking of the underwater three-stage separation system and quick butt joint and online installation between the underwater three-stage separation system and an underwater manifold and a submarine pipeline according to the follow-up drift effect of asymmetric air cell bodies on two sides of a balance pipe, the balance effect of the balance pipe and the air cell bodies, three-point hoisting of a connecting rigging and a three-cylinder automatic centering and locking mechanism between a capturing cylinder and a traction pipe, and is characterized in that:

the asymmetric online installation device adopts an asymmetric structure in the whole design, wherein the air cell body, the hoisting rigging, the connecting rigging, the catching cylinder and the traction tube are vertically arranged, and the balance tube and the hoisting base are horizontally arranged; the device comprises:

a gaseous body; the air cell body adopts an asymmetric double-air-cell structure, asymmetric double air cells of the air cell body comprise small air cells and large air cells, follow-up drifting is completed according to a spherical deviation adjusting mechanism, the horizontal deviation of the mounting device is automatically adjusted, and meanwhile, the vertical displacement of the mounting device is automatically adjusted according to an asymmetric balance effect; each part of the air cell body adopts a split structure, and the small air cells and the large air cells both adopt inverted cone-shaped air cells and are composed of an upper ball body and a lower cone body, wherein the upper ball body adopts a hemisphere, and the top of the upper ball body is provided with a column-shaped boss and is provided with an exhaust valve; the spherical deviation adjusting mechanism of the balloon body consists of a deviation adjusting sphere, a deviation adjusting gland and a deviation adjusting body, a spherical pair is adopted between the deviation adjusting sphere and the deviation adjusting gland as well as the deviation adjusting body, a semicircular spherical surface is processed at the central part of the upper end surface of the deviation adjusting body, the spherical center of the semicircular spherical surface of the deviation adjusting body is positioned on the axis of the deviation adjusting body, an annular groove is milled on the lower end surface of the deviation adjusting body flange plate, and a hexagonal metal ring is arranged in the annular groove; the center part of the upper end surface of the bias-adjusting cover is drilled with an inverted conical surface, the cavity wall of the bias-adjusting cover at the lower end of the inverted conical surface is processed with a semicircular spherical surface, the semicircular spherical surface of the bias-adjusting cover and the semicircular spherical surface of the bias-adjusting body are always concentric, and meanwhile, the cavity wall of the lower part of the semicircular spherical surface of the bias-adjusting cover is lined with a tubular pressing sleeve; the middle part of the deviation-adjusting sphere is sequentially provided with an inverted cone and a cylinder from top to bottom, the lower part of the deviation-adjusting sphere is provided with a spherical surface, the spherical surface is always concentric with the semi-spherical surfaces of the deviation-adjusting gland and the deviation-adjusting body, the spherical surface is provided with annular grooves which are arranged at equal intervals in a layered mode from top to bottom, and the lower end of the deviation-adjusting sphere is cut with a tangent plane parallel to the end face of the upper disc body;

a balance tube; the balance pipe is a horizontal long pipe body, flange plates are respectively arranged at two sides of the base pipe body, a blind flange is arranged at the outer side of each flange plate, so that the base pipe body is divided into independent closed chambers, three-way pipes are respectively arranged at the left side and the right side of the base pipe body, the left three-way pipe and the right three-way pipe are in asymmetric vertical arrangement, the flange plates are respectively arranged at the upper ends of the three-way pipes, and annular grooves with the same specification and size as those on the flange plates of the deviation adjusting body are processed on the upper end faces of the flange plates; the upper hanging seats and the middle support brackets are vertically arranged, wherein the upper hanging seats are symmetrically arranged on two sides of the upper pipe body of the base pipe body and positioned between the left three-way pipe and the right three-way pipe;

a hoisting rigging and a connecting rigging; the hoisting rigging consists of a main hoisting rope and two branch hoisting ropes, the main hoisting rope and the branch hoisting ropes are arranged in a star shape, the connecting rigging consists of three connecting ropes and three groups of lower supports, and the three connecting ropes are all arranged vertically; the main lifting rope, the branch lifting ropes and the connecting ropes are all composed of rope joints, connecting pipes and rope bodies, the main lifting rope is provided with one connecting pipe and one rope body, each branch lifting rope is provided with one rope joint, one connecting pipe and one rope body, meanwhile, each connecting rope is provided with two rope joints, two connecting pipes and one rope body, and each group of lower supports is formed by splicing two side plates which are parallel to each other and a horizontally placed flange plate;

a hoisting base; the hoisting base comprises an upper hoisting base and a lower hoisting base, the hoisting base is formed by splicing channel steel and I-steel, the overall profile of the hoisting base is ship-like, a main ship body in the middle of the hoisting base is rectangular, the ship bow on the left side of the hoisting base is isosceles trapezoid, and the ship stern on the right side of the hoisting base is rectangular, and three groups of catching cylinders and traction pipes are arranged on the hoisting base in a three-point mode to form a three-cylinder automatic centering mechanism;

a catching cylinder; the catching cylinder adopts three vertical thick-wall cylinders which are respectively arranged on the upper hoisting base; the capturing base cylinder is a cylinder body formed by combining a cylinder and a cone, cylindrical blind holes uniformly distributed along the circumferential direction are drilled on the wall of the middle cylinder of the capturing base cylinder, and a positioning shaft with a variable cross section is processed at the bottom of each cylindrical blind hole; a locking mechanism consisting of a lock pin and a lock spring is arranged in a cylindrical blind hole in the middle cylinder wall of the capturing base cylinder, the lock pin adopts a stepped shaft structure, and the end surface of the inner side of the lock pin is provided with a wedge-shaped groove;

a traction tube; the traction tube adopts three vertical long tube bodies which are respectively arranged on the lower hoisting base, and the overall outline of the traction tube is similar to a rocket; the supporting tube adopts a taper tube, the traction base tube is formed by welding the taper tube and a column tube, the taper of the outer wall conical surface of the taper tube of the traction base tube is consistent with the gradient of a wedge-shaped groove on the lock pin, and the middle part of the column tube of the traction base tube is drilled with a circular hole matched with the catching cylinder locking mechanism;

the asymmetric online installation method of the underwater three-level separation system is characterized in that a whole set of operation process is sequentially implemented by relying on an asymmetric online installation device, and comprises the following steps: the method comprises the following steps of underwater manifold measurement and positioning operation, separation system hoisting operation, asymmetric centering operation, air cell balance pipe recovery operation and separation system butt joint operation, so that the online rapid installation of the underwater three-stage separation system is completed.

2. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the exhaust valve, the deviation-adjusting sphere, the deviation-adjusting gland and the deviation-adjusting body of the air cell body respectively comprise a left monomer and a right monomer which have the same structure, the left monomer and the right monomer are respectively in one-to-one correspondence with the small air cell and the large air cell, and the axes of the left deviation-adjusting gland and the right deviation-adjusting gland and the deviation-adjusting body are kept parallel;

the small air cells of the air cell body and the lower cone of the large air cell body adopt inverted cones, and the large end circular surface at the upper part of the lower cone is tangent to the joint of the lower end surfaces of the upper spheres of the small air cells and the large air cell body;

the air cell body depends on wave force random load and ocean current internal wave force random load, and an offset adjusting ball body in the spherical offset adjusting mechanism automatically adjusts the angle and completes the follow-up drifting of small air cells and large air cells, so that the offset of the installation device in the horizontal direction is adjusted.

3. The asymmetric online installation method of the underwater three-stage separation system according to claim 1 or 2, characterized in that: the deviation adjusting body is a cylinder, and the lower part of the deviation adjusting body is connected with the balance pipe through a flange plate; the section of an annular groove on the lower end surface of the offset body flange plate is in an isosceles trapezoid shape, and a hexagonal metal ring arranged in the annular groove is a thick metal ring body;

the outer ring surface of the bias-adjusting gland is a conical surface and a cylindrical surface from top to bottom in sequence, the diameter of the small end circular surface of the inverted conical surface at the central part of the upper end surface of the bias-adjusting gland is larger than the outer diameter of a cylinder body in the middle of the bias-adjusting sphere, the taper of the inverted conical surface is larger than the bias-adjusting angle of the gas cell body, and the tubular pressing sleeve at the lower part of the semicircular spherical surface of the bias-adjusting gland connects the bias-adjusting gland with the bias-adjusting body through a sealing pipe thread;

the upper part of the offset-adjusting sphere is respectively connected with the small air cell and the large air cell through the disc body, and the taper of the inverted cone of the offset-adjusting sphere is equal to that of the inverted cone surface of the offset-adjusting gland; the spherical surface of the deviation-adjusting sphere, the deviation-adjusting gland and the semi-spherical surface of the deviation-adjusting body are in clearance fit to form a spherical pair, the cavity wall at the center of the tangent plane at the lower end of the deviation-adjusting sphere is of a structure combining a conical surface and a cylindrical surface, all layers of annular grooves on the spherical surface of the deviation-adjusting sphere are obliquely arranged along the spherical surface of the deviation-adjusting sphere, the conical vertex of the conical surface where the central line of each layer of annular groove is located is concentric with the spherical center of the spherical surface of the deviation-adjusting sphere, meanwhile, the upper two layers of annular grooves are matched with the semi-spherical surface of the deviation-adjusting gland, and the lower two layers of annular grooves are matched with the semi-spherical surface of the deviation-adjusting body.

4. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the balance pipe is connected with the balloon body and the hoisting rigging and is connected with the rigging in a downward connection mode, annular grooves with the same specification and size are formed in the combined end faces of the flange plates and the blind end flanges at the two side ends of the base pipe body, the two annular grooves in the flange plates and the blind end flanges are symmetrically arranged to form an annular cavity, and a hexagonal metal ring is configured in the annular cavity; the axes of the three-way pipes on the left side and the right side of the base pipe body are respectively superposed with the axes of the deviation adjusting gland and the deviation adjusting body, and central cylindrical surfaces formed by the central symmetry lines of the sections of the annular grooves on the flange plates of the three-way pipes on the left side and the right side and the deviation adjusting body are kept superposed with each other;

the left and right groups of middle supports in the balance pipe are positioned under the left and right three-way pipes, and the position of the middle group of middle supports is determined according to the axis of a first-stage separator in the underwater three-stage separator; each group of upper hanging seat and middle support bracket comprises two monomers which are arranged in parallel, and the two monomers of each group of upper hanging seat and middle support bracket are formed by combining a semicircular steel plate and a rectangular steel plate.

5. The asymmetric online installation method of the underwater three-stage separation system according to claim 1 or 4, characterized in that: the main lifting ropes of the hoisting rigging are positioned on the central symmetrical plane of the balance pipe and are connected to a crane lifting hook of a construction ship, and the two branch lifting ropes in the hoisting rigging are equal in length and are symmetrically arranged on two sides of the main lifting ropes and then are connected to the upper lifting seat;

the connecting rigging realizes three-point hoisting of the underwater three-stage separator, the lengths of the three connecting ropes are determined according to the positions of all interfaces of the underwater three-stage separator, and two ends of each connecting rope are respectively connected with the middle support and the lower support; the lower supports are vertically arranged and correspond to the middle supports one by one, and two side plates of each lower support are the same as the upper hanging seat and the middle support in structure and specification;

two rope connectors and a connecting pipe of a connecting rope in the connecting rigging are symmetrically arranged at two side ends of a rope body of the connecting rope and are connected into a whole, one side end of each of the rope connectors of the main lifting rope, the branch lifting rope and the connecting rope is formed by combining a semi-cylinder body and a square body, the other side end of each of the rope connectors adopts a variable cross-section shaft, the connecting pipe adopts a long pipe body, and the inner wall of the connecting pipe adopts a stepped revolution surface to fix the end part of the rope body.

6. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the structure and specification of an upper hoisting base and a lower hoisting base of the hoisting base are the same, the upper hoisting base completes prying and hoisting of the underwater three-stage separator, and the lower hoisting base is connected with the underwater Christmas tree and the underwater manifold into a whole and completes centering and supporting of the underwater three-stage separator; an underwater three-stage separator is arranged on a main ship body in the middle of the hoisting base, a group of capturing cylinders and traction pipes are arranged in the middle of a ship bow on the left side of the main ship body, and two groups of capturing cylinders and traction pipes are symmetrically arranged on two sides of a ship stern on the right side of the main ship body.

7. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the catching cylinder is provided with locking mechanisms which are uniformly arranged, the inner cylinder wall of the catching base cylinder adopts a variable cross-section revolving body structure, the middle part of the inner cylinder wall is drilled into a cylindrical surface, the upper end and the lower end of the cylindrical surface are respectively drilled into conical surfaces, the diameter of the small-end circular surface of the upper conical surface of the inner cylinder wall of the catching base cylinder is equal to that of the small-end circular surface of the middle cylindrical surface and that of the lower conical surface, and simultaneously, the taper and the taper height of the upper conical surface of the inner cylinder wall are both smaller than those of the lower conical surface of the inner cylinder wall; a positioning shaft at the bottom of the cylindrical blind hole of the capturing base cylinder adopts a stepped shaft structure, and a shaft shoulder is formed at the section change part of the positioning shaft to position one side end of a locking spring penetrating through the positioning shaft;

the outer ring surface of the lock pin of the capturing cylinder is precisely matched with the hole wall of the cylindrical blind hole of the capturing base cylinder to form a moving pair, and a wedge-shaped groove on the end surface of the inner side of the lock pin is arranged downwards; the section change position of the outer side end surface of the lock pin forms a shaft shoulder to position the other side end of the lock spring penetrating through the lock pin, and the lock pin is driven to slide inwards and outwards through the telescopic motion of the lock spring so as to realize the automatic locking between the catching cylinder and the traction tube.

8. The asymmetric online installation method of the underwater three-stage separation system according to claim 1 or 7, characterized in that: the traction tube realizes automatic centering in hoisting and centering operations through the traction capturing tube, a disc-shaped steel plate is welded at the lower end of the traction base tube, the bottom end of the disc-shaped steel plate is flush with the bottom end of the lower hoisting base, the diameter of the large end circular surface of the outer wall conical surface of the conical tube in the traction base tube and the outer diameter of the column tube in the traction base tube are both equal to the diameter of the cylindrical surface in the middle of the inner cylinder wall of the capturing base tube, and the hole wall of each circular hole in the middle of the column tube in the traction base tube is in clearance fit with the outer annular surface of the lock pin; the taper of the outer wall conical surface of the conical pipe in the supporting pipe is equal to the taper of the lower end conical surface of the inner cylinder wall of the catching base cylinder, and is simultaneously larger than the taper of the outer wall conical surface of the conical pipe in the traction base cylinder.

9. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the hoisting operation flow of the separation system comprises the steps that a vent valve is opened to sequentially fill micro-positive pressure gas into small cells and large cells of a cell body and a base pipe body of a balance pipe, the cell body, a hoisting rigging and a connecting rigging are connected into a whole through the balance pipe, then all catching cylinders are prefabricated on an upper hoisting base, prying of the underwater three-stage separator is completed through the upper hoisting base, and then the underwater three-stage separator is connected to the lower parts of the cell body and the balance pipe through three lower supports of the connecting rigging, so that three-point hoisting of the connecting rigging is realized; finally, according to the measured relative position parameters of the underwater manifold and the lower hoisting base, the underwater three-stage separator is lowered through a crane and a hoisting rigging on a construction ship, and the underwater three-stage separator is smoothly and stably hoisted to the interface position of the underwater manifold according to the following drift effect of the asymmetric type air cell body and the balance effect of the balance pipe and the air cell body in the hoisting and lowering process;

the asymmetric centering operation flow comprises the steps that wave force random loads and ocean current internal wave force random loads are balanced according to the following drifting effect of an asymmetric air cell body in the centering operation, the offset of the underwater three-stage separator in the horizontal direction is automatically adjusted, meanwhile, vertical oscillation loads are balanced according to the asymmetric balancing effect of the air cell body and a balancing pipe, and the vertical displacement of the underwater three-stage separator is automatically adjusted; then, an underwater robot and a three-cylinder automatic centering mechanism between the capturing cylinder and the traction pipe are utilized to realize automatic centering between the underwater three-stage separator and the upper hoisting base as well as the lower hoisting base; and finally, continuously hoisting and lowering the underwater three-stage separator, and realizing automatic locking among the underwater three-stage separator, the upper hoisting base and the lower hoisting base according to the matching between the lock pin of the locking mechanism configured in the capturing base cylinder and the circular hole on the traction base pipe.

10. The asymmetric online installation method of the underwater three-stage separation system according to claim 1, characterized in that: the process of the butt joint operation of the separation system comprises the steps of stably hoisting a connecting oil pipe to a connector at the lower end of an oil-gas collecting pipeline of the underwater three-stage separator through a crane, a hoisting rigging and a connecting rigging in sequence according to the balance function of a balance pipe, and connecting the underwater oil pipe to the underwater three-stage separator through an underwater robot and the connecting oil pipe; then, stably hoisting the connecting water pipe to a connector at the lower end of a drainage pipeline of the underwater three-stage separator, and connecting the underwater water pipe and the underwater three-stage separator into a whole by using the underwater robot and the connecting water pipe; and finally, stably hoisting the cross-over oil pipe to a position between the interface of the underwater manifold and the inlet of the underwater three-stage separator according to the balance action of the balance pipe, and connecting the underwater three-stage separator to the underwater Christmas tree and the underwater manifold by using the underwater robot and the cross-over oil pipe, so that the produced liquid of the submarine oil-gas well directly performs oil-gas-water separation and oily sewage treatment under water.

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