1. The installation method of the integrated steel cylinder underwater protection system is characterized by comprising the following steps of:

step S1: carrying out slope digging on an original soil layer of the surface of the sea bed to form a foundation pit with slopes on two sides;

step S2: vibrating and sinking the steel cylinder to a preset design depth in the foundation pit;

step S3: cutting the steel cylinder underwater, dismantling the steel cylinder above the cutting line, and slotting one side of the steel cylinder;

step S4: excavating a soil body in the steel cylinder;

step S5: paving a rubble layer in the steel cylinder;

step S6: drilling a water-resisting casing pipe, installing a Christmas tree and underwater equipment, wherein a pipeline of the underwater equipment penetrates out of the slotting position of the steel cylinder;

step S7: installing a sealing steel plate at the slotting position of the steel cylinder;

step S8: mounting a top cover on the steel cylinder;

step S9: and backfilling broken stones at the periphery of the outer side of the steel cylinder until the backfilled broken stones are flush with the original sea bed surface.

2. The method for installing an integrated steel cylinder underwater protection system as claimed in claim 1, wherein the step S6 comprises the steps of:

drilling, namely drilling a water-resisting casing downwards, wherein the water-resisting casing downwards sequentially penetrates through the gravel layer and the original soil layer;

arranging an underwater manifold, a jumper pipe, an electric flying line, a liquid flying line, a sea pipe, an umbilical cable and a cable, wherein the sea pipe is connected between the cylinder walls of the steel cylinders through flanges;

and installing a Christmas tree at the top of the riser.

Background

In recent years, the dependence of oil and gas energy resources in China rises year by year, the dependence is close to 70 percent and exceeds 60 percent of internationally recognized warning lines, the national energy safety situation is severe, and the development of the oil and gas resources is increased at will. For the development of oil and gas resources in a Bohai restricted area, safety of navigation and underwater production facilities is considered by related departments, and oil and gas resource exploitation facilities are required to be not higher than a sea bed surface. Therefore, the development mode of the seabed underwater production system is an effective scheme of oil and gas resources in the disc-living Bohai sea restricted area. The integrated steel cylinder underwater protection system is an effective scheme for protecting an underwater production system, the construction and installation process of the integrated steel cylinder underwater protection system is complex, the types of required installation equipment are more, various construction processes such as vibration and sinking, hoisting, dredging and the like are included, and the installation requirement of the steel cylinder protection system cannot be met by a conventional hoisting mode.

Disclosure of Invention

The invention aims to provide an installation method of an integrated steel cylinder underwater protection system.

The invention provides an installation method of an integrated steel cylinder underwater protection system, which comprises the following steps:

step S1: carrying out slope digging on an original soil layer of the surface of the sea bed to form a foundation pit with slopes on two sides;

step S2: vibrating and sinking the steel cylinder in the foundation pit to a preset design depth;

step S3: cutting the steel cylinder underwater, dismantling the steel cylinder above the cutting line, and slotting one side of the steel cylinder;

step S4: excavating a soil body in the steel cylinder;

step S5: paving a rubble layer in the steel cylinder;

step S6: drilling a water-resisting casing pipe, installing a Christmas tree and underwater equipment, wherein a pipeline of the underwater equipment penetrates out of the slotting position of the steel cylinder;

step S7: installing a sealing steel plate at the slotting position of the steel cylinder;

step S8: mounting a top cover on the steel cylinder;

step S9: and backfilling broken stones at the periphery of the outer side of the steel cylinder until the backfilled broken stones are flush with the original sea bed surface.

Preferably, the step S6 includes the steps of:

drilling, namely drilling a water-resisting casing downwards, wherein the water-resisting casing downwards sequentially penetrates through the gravel layer and the original soil layer;

arranging an underwater manifold, a jumper pipe, an electric flying line, a liquid flying line, a sea pipe, an umbilical cable and a cable, wherein the sea pipe is connected between the cylinder walls of the steel cylinders through flanges;

and installing a Christmas tree at the top of the riser.

Compared with the prior art, the invention has the beneficial effects that:

the invention discloses an installation method of an integrated steel cylinder underwater protection system, which comprises the following steps: the method comprises the following steps of (1) carrying out slope excavation on an original soil layer of a sea bed surface to form a foundation pit with slopes on two sides, ensuring that the slope of the foundation pit is still in a stable state when the integrated steel cylinder underwater protection system is installed, basically having no back-silting or only having a small amount of back-silting, and ensuring safe butt joint of underwater sea pipes, umbilical cables and cables at the position of a steel cylinder; vibrating and sinking the large-diameter steel cylinder to a preset design depth below the surface of the sea bed; cutting and dismantling the steel cylinder above the surface of the sea bed under water to ensure that the top of the steel cylinder entering the mud does not exceed the original surface of the sea bed, and performing underwater cutting and slotting on one side of the steel cylinder; excavating original soil in the steel cylinder to a preset depth; paving a rubble layer inside the steel cylinder so as to install underwater equipment and the like; after the underwater equipment is installed, installing a sealing steel plate at the slotting position of the steel cylinder and covering a top cover; and gravel is backfilled at the periphery of the outer side of the steel cylinder, and the height of the gravel is not higher than that of the original sea bed surface after backfilling, so that the seabed scouring and accumulation formed at the periphery of the steel cylinder are effectively prevented. The mounting method of the integrated steel cylinder underwater protection system disclosed by the invention has the advantages of rapidness and rapidness in mounting, high efficiency, high reliability and the like, provides powerful technical support for development of oil and gas resources in a Bohai sea restricted area, and has a wide application prospect.

Drawings

Fig. 1 is a schematic diagram of the sloping excavation of a sea bed surface provided in embodiment 1 of the present invention;

FIG. 2 is a schematic illustration of the steel cylinder vibro-sinking provided in example 1 of the present invention;

FIG. 3 is a schematic view of an underwater cutting steel cylinder provided in example 1 of the present invention;

fig. 4 is a schematic diagram of the original soil excavation and the gravel layer laying inside the steel cylinder provided in embodiment 1 of the present invention;

fig. 5 is a schematic diagram of installation of a christmas tree according to embodiment 1 of the present invention;

FIG. 6 is a schematic diagram of the installation of subsea equipment provided in embodiment 1 of the present invention;

FIG. 7 is a schematic view of the installation of a top cover on a steel cylinder according to embodiment 1 of the present invention;

fig. 8 is a schematic diagram of backfilling a crushed stone layer at the outer periphery of a steel cylinder according to example 1 of the present invention.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Example 1

The embodiment 1 provides an installation method of an integrated steel cylinder underwater protection system, which specifically comprises the following steps:

step S1: carrying out slope-releasing excavation on an original soil layer of the surface of the sea bed to form a foundation pit with slopes on two sides;

aiming at the site of an oil and gas field, according to the position of a wellhead, by combining the arrangement scheme of equipment such as an underwater wellhead, a manifold and the like, a slope-releasing mode is adopted, and a dredger is used for excavating the original soil layer on the surface layer of the seabed to form a foundation pit. Wherein, the slope ratio depends on the engineering geological conditions of the field, as shown in figure 1, 1: 2, when the integrated steel cylinder underwater protection system is installed, the foundation pit side slope is still in a stable state, and is basically not subjected to back-silting or only subjected to a small amount of back-silting, so that safe butt joint of an underwater sea pipe, an umbilical cable and a cable at the position of the steel cylinder is guaranteed; the excavation depth is about 2.5m to 3 m.

Step S2: vibrating and sinking the steel cylinder to a preset design depth in the foundation pit;

selecting a large-diameter steel cylinder, adopting a multi-hammer linkage vibration device such as a twelve-hammer and the like, vibrating and sinking on water, and vibrating and sinking the large-diameter steel cylinder to a preset depth below a sea bed surface, wherein the vibration and sinking depth cannot be lower than the preset depth, as shown in figure 2.

Step S3: cutting the steel cylinder underwater, dismantling the steel cylinder above the cutting line, and slotting one side of the steel cylinder;

referring to fig. 3, the steel cylinder above the surface of the sea bed is cut underwater to a depth within 0.5m below the surface of the sea bed, and the levelness of the top surface of the steel cylinder after cutting is guaranteed as much as possible in the cutting process;

after the steel cylinder is cut, the steel cylinder above the cutting line is dismantled, so that the top of the steel cylinder filled with mud is slightly lower than the original sea bed surface;

one side of the steel cylinder is subjected to underwater cutting and slotting, and the slotting depth is about 2.5m, so that a sea pipe, an umbilical cable, a cable and the like can be installed conveniently.

Step S4: excavating a soil body in the steel cylinder;

excavating an original soil layer inside the steel cylinder by using a dredger and a dredge pump until the original soil layer inside the steel cylinder is excavated to a preset depth; the predetermined depth needs to be determined according to specific engineering requirements.

Step S5: paving a rubble layer in the steel cylinder;

referring to fig. 4, a layer of crushed stone is paved inside the steel cylinder in a directional guide cylinder mode to form a crushed stone layer, the thickness of the crushed stone layer is about 1m, and the particle size of the crushed stone is not more than 5 cm.

Step S6: drilling a water-resisting casing pipe, installing a Christmas tree and underwater equipment, and enabling an underwater pipe cable to penetrate out of the slotting position of the steel cylinder;

drilling, namely drilling a water-resisting casing downwards, wherein the water-resisting casing downwards sequentially penetrates through the gravel layer and the original soil layer;

installing a Christmas tree on top of the riser, as shown in FIG. 5

Arranging pipelines such as an underwater manifold, a jumper pipe, an electric flying line, a liquid flying line, a sea pipe, an umbilical cable, a cable and the like, wherein the sea pipe is connected between the cylinder walls of the steel cylinders through flanges;

step S7: installing a sealing steel plate at the slotting position of the steel cylinder;

installing a sealing steel plate at the slotting position of the steel cylinder to realize underwater sealing, as shown in FIG. 6;

step S8: mounting a top cover on the steel cylinder;

the top cover is arranged on the steel cylinder in a hoisting mode, and the top layer is not higher than the original sea bed surface, as shown in figure 7;

step S9: and backfilling broken stones at the periphery of the outer side of the steel cylinder until the backfilled broken stones are flush with the original sea bed surface.

And (3) forming a foundation pit after the sea bed surface is excavated, selecting broken stones as backfill materials for the foundation pit formed outside the steel cylinder, backfilling the foundation pit excavated outside the sea bed surface outside the steel cylinder until the backfilled broken stones are level with the original sea bed surface, recovering the sea bed height and protecting the integrated steel cylinder underwater protection system, and referring to fig. 8.

Wherein, integration steel cylinder underwater protection system includes: the device comprises a steel cylinder, an original soil layer, a gravel layer, a sealing steel plate, a steel cylinder top cover and gravel backfilled outside the steel cylinder.

The steel cylinder is a large-diameter steel cylinder, an original soil layer is arranged inside the steel cylinder, a gravel layer is laid on the original soil layer, the Christmas tree and the underwater equipment are arranged on the gravel layer, the top end of the waterproof casing is communicated with the Christmas tree, the lower end of the waterproof casing extends downwards to sequentially penetrate through the gravel layer and the original soil layer, and the Christmas tree and the underwater equipment are connected through a pipeline;

the top cover is arranged at the top end of the steel cylinder.

One side of the steel cylinder is provided with a groove, and a steel plate is arranged at the position of the groove of the steel cylinder.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.