Dry-type protection system mounting method for underwater oil and gas development

Abstract

The invention discloses an installation method of a dry-type protection system for underwater oil and gas development. The dry-type protection system comprises a waterproof section and an installation section, and pile group sleeves are fixedly arranged on the outer side wall, close to the bottom, of the installation section; the method comprises the steps that S1, on the land, a waterproof section is fixed to the upper end of a mounting section, the joint of the waterproof section and the mounting section is sealed, and a protection system is obtained; s2, the protection system is put into water, and the protection system and the seabed are fixed by driving steel piles into pile group sleeves; s3, after the protection system is fixed, water in the protection system is drained, and a dry type operation environment is formed; s4, well drilling, structure installation and equipment debugging work are conducted in the dry type operation environment, and after equipment debugging is completed, a protective top cover is installed at a well mouth and sealed; and S5, after sealing is completed, the waterproof section is dismantled, and the workload of underwater operation is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of marine oil and gas development engineering, and particularly relates to an installation method for a dry protection system for underwater oil and gas development. Background Technology

[0002] In the process of oil and gas resource development, jacket platform development has always occupied a mainstream position. With its mature technology system, stable operation performance, and ease of maintenance and management, this development method has long provided important support for the efficient exploitation of oil and gas resources. It has been widely used in most developed conventional oil and gas fields, effectively promoting the development of the offshore oil and gas industry.

[0003] However, with the continuous advancement of exploration technology and the sustained increase in oil and gas resource exploration efforts, the distribution of proven oil and gas reserves has shown new characteristics. Large amounts of untapped oil and gas resources exist in special areas such as navigation-restricted zones. Due to the constraints of navigation conditions and other special factors, traditional jacket platform development methods are unsuitable for these areas. After extensive technical demonstrations and practical explorations, the industry generally agrees that subsea or subsurface production systems are a more suitable option for oil and gas development in these special areas. This development method eliminates the need to build large platforms on the sea surface, better adapts to the environmental requirements of these special areas, reduces the impact on normal activities within the region, and opens up new pathways for the development of oil and gas resources in these special areas.

[0004] Current traditional underwater development models still face many prominent problems in practical applications. Traditional underwater development models mostly employ wet installation processes, which are highly dependent on external conditions and resources during operation: on the one hand, they heavily rely on divers for underwater operations, requiring divers to complete a series of high-precision tasks such as equipment installation, connection, and debugging in complex and ever-changing marine environments; on the other hand, they also heavily rely on complex underwater engineering equipment, with various specialized underwater installation and testing equipment being indispensable, resulting in prominent problems such as long construction cycles, high safety risks, and difficulties in cost control.

[0005] Therefore, there is an urgent need to design a dry protection system installation method for underwater oil and gas development to solve the problems mentioned above. Summary of the Invention

[0006] The purpose of this invention is to provide a method for installing a dry protection system for underwater oil and gas development, thereby reducing the workload of underwater operations.

[0007] To achieve the above objectives, the specific technical solution of the installation method of a dry protection system for underwater oil and gas development according to the present invention is as follows: A method for installing a dry protection system for underwater oil and gas development includes: a water-proof section, an installation section, and a pile sleeve fixedly installed on the outer wall of the installation section near the bottom. S1: On land, the waterproof section is fixed to the upper end of the mounting section, and the connection between the waterproof section and the mounting section is sealed to obtain a protective system; S2: The protective system is placed in the water, and the protective system is fixed to the seabed by driving steel piles into the pile sleeve; S3: After the protective system is fixed, drain the water from the inside of the protective system to create a dry working environment; S4: Drilling, structure installation and equipment commissioning are carried out in a dry working environment. After the equipment commissioning is completed, a protective top cover is installed at the wellhead and the protective top cover is sealed. S5: After sealing the protective top cover, remove the waterproof section.

[0008] Furthermore, step S2 also includes monitoring the verticality of the steel piles in real time and adjusting the protection system by means of a hydraulic leveling device during the process of driving the steel piles into the pile sleeve to fix the protection system to the seabed.

[0009] Furthermore, the contact area between the bottom of the protective system and the seabed is not less than 95% of the bottom area of ​​the protective system.

[0010] Furthermore, the bottom of the protective system is provided with a guide hole. Step S2 also includes installing the waterproof sleeve into the guide hole after the protective system is fixed to the seabed, and sealing the waterproof sleeve and the protective system by cement grouting.

[0011] Furthermore, installing the water-proof sleeve into the guide hole includes the following steps: hoisting the water-proof sleeve to the top of the guide hole using a floating crane, connecting the water-proof sleeve to the guide hole, allowing the water-proof sleeve to freely descend into the mud under gravity until the load of the floating crane drops to 0, and then starting the hydraulic pile hammer to strike the water-proof sleeve to the set position.

[0012] Furthermore, the installation section and the waterproof section adopt a stepped mating structure, and the diameter difference between the installation section and the waterproof section is 50~100mm.

[0013] Furthermore, a sealing groove is provided on the contact surface between the installation section and the water-proof section, and rubber is filled in the sealing groove.

[0014] Furthermore, in step S2, a lifting lug is fixedly installed on the outer wall of the installation section, and the protective system is lifted into the water by using a floating crane to fix the lifting lug.

[0015] Furthermore, in step S4, the protective top cover is hoisted to the top of the protective system using a floating crane, and the position of the protective top cover is finely adjusted using a positioning beacon and a traction cable so that the protective top cover can be fixed to the top of the installation section with bolts.

[0016] Furthermore, in step S5, removing the waterproof section includes the following steps: lifting the waterproof section with a floating crane to break the seal at the connection between the waterproof section and the installation section, and monitoring the internal pressure of the protection system in real time during the breaking process.

[0017] The dry protection system installation method for underwater oil and gas development of the present invention has the following advantages: The dry working environment avoids the influence of harsh marine conditions such as tides and waves, eliminating reliance on limited weather windows and significantly improving operational continuity while reducing environmental dependence. Most assembly, sealing, and drilling operations do not require underwater diving, reducing personnel safety risks and minimizing diving operations. Land-based assembly reduces underwater work, and equipment installation and commissioning are more convenient in the dry environment, shortening the construction cycle and improving operational efficiency. Steel pile fixing, leveling control, and multiple sealing designs ensure the stability and reliability of the protection system, allowing it to adapt to the marine environment long-term and guaranteeing structural stability. The watertight section is recyclable and reusable, reducing material waste, shortening the construction period, reducing safety risks, and indirectly lowering development costs, thus saving costs. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the installation method of the dry protection system for underwater oil and gas development according to the present invention. Figure 2 This is a top view of the installation method of the dry protection system for underwater oil and gas development according to the present invention; Figure 3 This is a schematic diagram of the installation method of the dry protection system for underwater oil and gas development according to the present invention. Figure 4 This is a schematic diagram of the pumping equipment operation in the dry protection system installation method for underwater oil and gas development according to the present invention. Figure 5 This is a schematic diagram of the structure for installing the protective top cover in the dry protection system installation method for underwater oil and gas development according to the present invention. Figure 6 This is a schematic diagram of the structure after the watertight section is removed in the installation method of the dry protection system for underwater oil and gas development according to the present invention.

[0019] Explanation of markings in the diagram: 1. Installation section; 2. Waterproof section; 3. Lifting lug; 4. Guide hole; 5. Pile casing; 6. Steel pile; 7. Pumping equipment; 8. Protective top cover; 9. Seabed; 10. Seawater; 11. Waterproof sleeve. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0022] The following is a reference to the appendix. Figure 1 To be continued Figure 6 This invention describes an installation method for a dry protection system for underwater oil and gas development.

[0023] like Figures 1 to 6 As shown, a method for installing a dry protection system for underwater oil and gas development includes: a water-proof section 2, an installation section 1, and a pile sleeve 5 fixedly installed on the outer wall of the installation section 1 near the bottom. S1: On land, the waterproof section 2 is fixed to the upper end of the mounting section 1, and the connection between the waterproof section 2 and the mounting section 1 is sealed to obtain a protective system; Specifically, the assembly and sealing inspection of the protective system are completed at the land-based work site. First, the waterproof section 2 is fixed to the upper end of the installation section 1, and the two are stably assembled using a pre-designed connection structure. Then, the connection between the waterproof section 2 and the installation section 1 is sealed to ensure that seawater 10 will not seep into the system during subsequent underwater operations, ultimately forming a complete protective system. This step transfers most of the assembly work to land, significantly reducing the workload of underwater operations and lowering the operational difficulty and safety risks.

[0024] S2: The protective system is placed in the water, and the protective system is fixed to the seabed 9 by driving steel piles 6 into the pile sleeve 5; Specifically, the protective system, assembled on land, is slowly lowered into the target sea area using specialized hoisting equipment. Once the system has sunk close to the seabed 9, steel piles 6 are sequentially driven into the pile sleeves 5 on the outer wall of the installation section 1. The steel piles 6 must penetrate the surface soil of the seabed 9 to a stable stratum. Through the cooperation of the steel piles 6 and the pile sleeves 5, the protective system is firmly fixed to the seabed 9, providing a stable foundation for the subsequent construction of the dry working environment.

[0025] S3: After the protective system is fixed, drain the water from the inside of the protective system to create a dry working environment; Specifically, after the protective system is fixed to the seabed 9, the pumping equipment 7 is activated to pump out the seawater 10 that has been injected into the protective system. The pumping process must ensure that there is no residual seawater 10 inside the protective system, so that a dry working environment isolated from the external seawater 10 is formed inside the protective system. This creates waterless operating conditions for subsequent drilling, structure installation and other operations, and avoids interference from seawater 10 in the operation process.

[0026] S4: Drilling, structure installation and equipment commissioning are carried out in a dry working environment. After the equipment commissioning is completed, a protective top cover 8 is installed at the wellhead and the protective top cover 8 is sealed. Specifically, within the dry environment of the protection system, drilling operations (including drilling, cementing, etc.), installation of subsea oil and gas production structures (such as wellheads and pipelines), and commissioning of electrical and hydraulic systems are carried out sequentially. After the equipment commissioning is completed, a protective cap 8 is installed above the wellhead, and the connection between the protective cap 8 and the protection system is sealed to prevent seawater 10 from seeping into the system, ensuring the stability of the dry environment and providing long-term protection for the wellhead.

[0027] S5: After sealing the protective top cover 8, remove the water-proof section 2.

[0028] Specifically, after the protective top cover 8 is sealed, the water-tight section 2 at the top of the protective system is removed. The removal process requires specialized hoisting equipment to ensure smooth operation and avoid damage to other internal structures of the protective system. After the water-tight section 2 is removed, the remaining portion of the protective system can be used for long-term protection during oil and gas production processes, while the removed water-tight section 2 can be recycled and reused, reducing resource waste.

[0029] Furthermore, such as Figures 3 to 6 As shown, step S2 also includes real-time monitoring of the verticality of the steel pile 6 during the process of driving the steel pile 6 into the pile sleeve 5 to fix the protection system to the seabed 9, and adjusting the protection system by means of a hydraulic leveling device.

[0030] Specifically, in step S2, during the process of vertically driving the steel pile 6 into the pile sleeve 5 to fix the protective system, the verticality of the steel pile 6 needs to be monitored in real time. Monitoring the verticality of the steel pile 6 includes installing a verticality sensor on the steel pile 6 and using a data transmission system to feed the real-time data from the verticality sensor back to the control console. If the verticality deviation of the steel pile 6 is found to exceed the preset range, the hydraulic leveling device is activated to adjust the base posture of the protective system. The hydraulic leveling device fine-tunes the support height at different positions of the protective system to ensure that the verticality of the steel pile 6 meets the design requirements, preventing instability of the protective system due to the tilting of the steel pile 6 and ensuring the safety of subsequent operations.

[0031] Furthermore, the contact area between the bottom of the protective system and the seabed 9 is not less than 95% of the bottom area of ​​the protective system.

[0032] Specifically, to further ensure the stability of the protection system, after adjusting the system using the hydraulic leveling device in step S2, it is necessary to ensure that the contact area between the bottom of the protection system and the seabed 9 is not less than 95% of the bottom area of ​​the protection system. The contact area can be controlled by monitoring the contact pressure between each area of ​​the bottom of the protection system and the seabed 9 using pressure sensors. If there are areas with insufficient or no contact pressure, the hydraulic leveling device should be used for further adjustment until the contact area meets the standard. After leveling, the top of the steel pile 6 is welded and fixed to the pile sleeve 5. Sufficient contact area can distribute the weight of the protection system, preventing excessive local pressure from causing the system to sink or tilt, thus providing reliable support for dry operation environments.

[0033] Furthermore, such as Figure 5 As shown, the bottom of the protective system is provided with a guide hole 4. Step S2 also includes installing the waterproof sleeve 11 into the guide hole 4 after the protective system is fixed to the seabed 9, and sealing the waterproof sleeve 11 and the protective system by cement grouting.

[0034] Specifically, the bottom of the protective system has a guide hole 4 corresponding to the wellhead. With the assistance of a diver, the riser sleeve 11 is positioned and connected to the guide hole 4. After the protective system is fixed to the seabed 9 in step S2, additional installation and sealing of the riser sleeve 11 is required. The riser sleeve 11 is installed by aligning it with the bottom guide hole 4. As an isolation structure between the wellhead and the external environment, the riser sleeve 11 further prevents seawater 10 from seeping into the wellhead area. After installation, the gap between the riser sleeve 11 and the protective system is sealed using cement grouting. The cement grout must fill the gap completely, and after the cement hardens, a tight sealing layer is formed, ensuring the waterproof performance of the wellhead area and providing safety for subsequent drilling operations.

[0035] Specifically, after the water-proof sleeve 11 is in place, high-strength cement grout (water-cement ratio of 0.4~0.5, compressive strength ≥35MPa) is injected into the annular gap between the water-proof sleeve 11 and the installation section 1. Before grouting, grouting pipes and vent holes need to be installed. The grouting process is divided into two stages: the initial grouting is carried out to 70% of the gap, and after standing for 24 hours to allow the cement to initially set, the grouting is continued until the gap is full, ensuring that there are no air holes or leaks between the water-proof sleeve 11 and the installation section 1.

[0036] Further, installing the water-proof sleeve 11 into the guide hole 4 includes the following steps: hoisting the water-proof sleeve 11 to the top of the guide hole 4 using a floating crane, connecting the water-proof sleeve 11 to the guide hole 4, allowing the water-proof sleeve 11 to freely descend into the mud under gravity until the load of the floating crane drops to 0, and then starting the hydraulic pile hammer to strike the water-proof sleeve 11 to the set position.

[0037] Specifically, the riser sleeve 11 is first hoisted to a position directly above the guide hole 4 at the bottom of the protection system using a floating crane. With the assistance of divers or guided by visual positioning equipment, the riser sleeve 11 is precisely aligned with the guide hole 4. In the initial stage, the riser sleeve 11 is allowed to sink freely into the mud under its own weight, with the load changes of the floating crane monitored in real time. When the load on the floating crane drops to 0, it indicates that the riser sleeve 11 is completely supported by the seabed 9. At this point, the hydraulic pile hammer is activated to apply impact force to the top of the riser sleeve 11, driving it to the designed depth to ensure that the bottom of the riser sleeve 11 is deeply embedded in stable strata, thereby improving structural stability.

[0038] Furthermore, the installation section 1 and the water-proof section 2 adopt a stepped mating structure, and the diameter difference between the installation section 1 and the water-proof section 2 is 50~100mm.

[0039] Specifically, to achieve a stable connection and seal between installation section 1 and water-proof section 2, a stepped mating structure is adopted. The diameter of water-proof section 2 is slightly smaller than that of installation section 1, meaning the upper outer diameter of installation section 1 matches the lower inner diameter of water-proof section 2, forming a stepped mating surface. Pressure-resistant sealing material (such as polyurethane sealant or rubber gaskets) is evenly applied to the contact areas of both installation section 1 and water-proof section 2, and a hydraulic tester is used to check the sealing performance of the connection, ensuring that the pressure value meets the design requirements (usually 1.5 times the working pressure). The diameter difference between installation section 1 and water-proof section 2 is controlled between 50 and 100 mm. This range has been verified through mechanical calculations and practical testing, ensuring both ease of assembly and structural strength after mating. This avoids loosening due to excessive diameter difference or assembly difficulties due to insufficient difference, while also reserving reasonable space for subsequent sealing treatment.

[0040] Furthermore, a sealing groove is provided on the contact surface between the installation section 1 and the water-proof section 2, and rubber is filled in the sealing groove.

[0041] Specifically, a sealing channel is pre-formed at the stepped contact surface between installation section 1 and water-proof section 2. The cross-sectional shape of the sealing channel is rectangular or trapezoidal, and the depth and width of the channel are designed according to the sealing requirements. During assembly, rubber material (preferably water-swellable rubber) is filled into the sealing channel. The water-swellable rubber expands upon contact with seawater 10, tightly filling the tiny gaps between the channel and the contact surface, forming a double sealing effect. Compared with ordinary sealing materials, water-swellable rubber can further improve the sealing reliability and effectively prevent seawater 10 from seeping into the interior of the protection system from the connection between installation section 1 and water-proof section 2.

[0042] Furthermore, in step S2, a lifting lug 3 is fixedly installed on the outer wall of the installation section 1, and the protective system is lifted into the water by using a floating crane to fix the lifting lug 3.

[0043] Specifically, in step S2, to ensure the smooth lifting and launching of the protective system, lifting lugs 3 are fixedly installed on the outer wall of installation section 1. There are no fewer than four lifting lugs 3, and they are evenly distributed along the circumference of installation section 1 to ensure the protective system is under balanced stress during lifting. The lifting lugs 3 are welded and fixed to the outer side of installation section 1 using high-strength steel. The weld joints must undergo flaw detection to ensure the weld strength meets the lifting load requirements. During lifting, the hook of the floating crane is precisely connected to the lifting lugs 3. Through slow lifting, moving, and lowering operations, the protective system is smoothly placed into the water, preventing tilting or collision during the lifting process. The position of the lifting lugs 3 is offset from the pile sleeve 5 to avoid interference with the pile driving process.

[0044] Further, in step S4, the protective top cover 8 is hoisted to the top of the protective system by a floating crane, and the position of the protective top cover 8 is finely adjusted by a positioning beacon and a traction cable so that the protective top cover 8 can be fixed to the top of the installation section 1 by bolts.

[0045] Specifically, the installation process of the protective top cover 8 in step S4 is as follows: First, the protective top cover 8 is hoisted to the top of the protective system using a floating crane. At this time, the positioning beacons installed on the protective top cover 8 and the protective system are activated to obtain the relative position data of the two in real time through the beacon signals. Simultaneously, the position of the protective top cover 8 is finely adjusted using a traction cable (such as a wire rope traction mechanism). Double rubber sealing rings are installed between the protective top cover 8 and the top of the installation section 1 to ensure that the mounting holes of the protective top cover 8 are precisely aligned with the bolt holes on the top of the installation section 1. After the position calibration is completed, the protective top cover 8 is fixedly connected to the top of the installation section 1 using bolts. The bolts must be made of corrosion-resistant material, and the tightening torque must meet the design requirements to ensure a firm connection. Sealing treatment is then performed to ensure the sealing performance of the protective top cover 8 and the protective system.

[0046] Furthermore, in step S5, removing the waterproof section 2 includes the following steps: lifting the waterproof section 2 with a floating crane to break the seal at the connection between the waterproof section 2 and the installation section 1, and monitoring the pressure inside the protection system in real time during the breaking process.

[0047] Specifically, the dismantling of the water-proof section 2 in step S5 should follow these steps: First, connect the hook of the floating crane to the lifting lug 3 at the top of the water-proof section 2. The floating crane slowly applies a lifting force to gradually loosen the connection between the water-proof section 2 and the installation section 1. Then, use special tools to remove the sealing material (such as water-swellable rubber, sealant, etc.) at the connection between the water-proof section 2 and the installation section 1. During the removal process, the pressure inside the protection system needs to be monitored in real time. The internal pressure data of the protection system is fed back to the control console through the pressure sensor. If the pressure fluctuates abnormally (such as a sudden drop or rise in pressure), the operation should be stopped immediately to check for sealing failure or structural damage. After the pressure returns to normal, the dismantling operation can continue. Finally, the water-proof section 2 is completely recovered to the water surface to avoid affecting the dry environment inside the protection system or the wellhead equipment and causing structural instability.

[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method of installing a dry protection system for subsea oil and gas development, characterised in that, The application relates to a protection system for offshore drilling and installation. The protection system comprises a water isolation section, a mounting section, and a group pile sleeve fixedly arranged on the outer side wall of the mounting section close to the bottom. S1: fixing the water isolation section on the upper end of the mounting section on land, and sealing the connection between the water isolation section and the mounting section to obtain a protection system; S2: placing the protection system in water, and fixing the protection system to the seabed by driving steel piles into the group pile sleeve; S3: after the fixing of the protection system is completed, the water in the protection system is pumped out to form a dry operation environment; S4: drilling, structure installation and equipment debugging are carried out in the dry operation environment, and after the equipment debugging is completed, a protective top cover is installed on the wellhead, and the protective top cover is sealed; S5: after the sealing of the protective top cover is completed, the water isolation section is removed.

2. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, In the process of fixing the protection system to the seabed by driving the steel piles into the group pile sleeve, the verticality of the steel piles is monitored in real time, and the protection system is adjusted by a hydraulic leveling device.

3. The dry protection system installation method for subsea oil and gas development according to claim 2, characterized by, The contact area of the bottom of the protection system with the seabed is not less than 95% of the area of the bottom of the protection system.

4. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, The bottom of the protection system is provided with a guide hole, and after the fixing of the protection system to the seabed is completed, the water isolation casing is installed into the guide hole, and the water isolation casing and the protection system are sealed by cement grouting.

5. The dry protection system installation method for subsea oil and gas development according to claim 4, characterized by, The installation of the water isolation casing into the guide hole comprises the following steps: the water isolation casing is lifted to the upper side of the guide hole by a floating crane, the water isolation casing is butted into the guide hole, the water isolation casing freely falls under the action of gravity until the load of the floating crane is reduced to 0, and then a hydraulic pile hammer is started to strike the water isolation casing to a set position.

6. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, The mounting section and the water isolation section adopt a stepped matching structure, and the diameter difference between the mounting section and the water isolation section is 50-100 mm.

7. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, The contact surface of the mounting section and the water isolation section is provided with a sealing groove, and the sealing groove is filled with rubber.

8. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, In step S2, a lifting lug is fixedly arranged on the outer side wall of the mounting section, and the protection system is lifted into water by fixing the lifting lug by the floating crane.

9. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, In step S4, the protective top cover is lifted to the top of the protection system by the floating crane, the position of the protective top cover is finely adjusted by a positioning beacon and a traction cable, so that the protective top cover and the top of the mounting section are fixed by bolts.

10. The dry protection system installation method for subsea oil and gas development according to claim 1, characterized by, In step S5, the removal of the water isolation section comprises the following steps: the water isolation section is pulled up by the floating crane, the sealing at the connection between the water isolation section and the mounting section is broken, and the pressure in the protection system is monitored in real time during the breaking process.

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