Ocean directional drilling construction method on land

Abstract

The invention provides a land-to-sea directional drilling construction method, which comprises the following steps of: 1, exploring geology, and determining a land buried point, a sea unearthed point and a path according to an exploration result; 2, according to the land penetrating point, the offshore unearthing point and the path, guide hole drilling and reaming construction is conducted from the land to the offshore, and after completion, a pull-back drill rod and a reamer in a guide hole are reserved; and thirdly, after the steel pipes are welded and detected on the land and are accepted and accepted to be qualified, embankment penetrating construction is conducted from the land buried point to the offshore unearthed point. According to the method, the traditional submarine cable laying process is remarkably simplified, multiple auxiliary ships do not need to be deployed on the sea to carry out complex operation, the requirements for equipment and personnel are reduced, and the operation cost is also reduced. More importantly, the method has no special limitation on operation time. Compared with the prior art, the whole construction process is simpler, more flexible and more efficient, and different environmental conditions and project progress requirements can be better met.

Description

Technical Field

[0001] The invention relates to the technical field of submarine cable laying, and in particular to a directional drilling construction method from land to sea. Background Art

[0002] During the construction of the output cable of the offshore wind power project, the construction of the tidal flat section is mainly protected by excavation and landfill by amphibious excavators due to the influence of tidal changes in the geographical location, and the deep water section adopts the form of flushing and burying protection by submarine cable laying vessels. This results in the need to use cast iron casing, cement row, riprap protection and other protection forms for the submarine cable protection construction at the construction location that neither excavators nor submarine cable laying vessels can reach, which increases the project cost.

[0003] In order to reduce the damage to the ecological environment and lower the cost of the project, directional drilling construction for laying cables (such as power cables, communication optical cables, etc.) that need to cross waters such as rivers, straits or shallow sea areas has become a research hotspot in this field. The entire directional drilling construction process does not require earth excavation of the offshore tidal flat section, reduces damage to the marine ecological environment, and can greatly shorten the distance of special protection of the construction location that neither the excavator nor the submarine cable laying ship can reach. However, the directional drilling construction method of the prior art has the following problems in the actual construction process:

[0004] 1. The submarine cable is towed back from the unearthed end at sea to the buried end on land. Multiple auxiliary ships are required for auxiliary operations, and the operation needs to be carried out at a specific high tide time. The entire construction process is relatively complicated and the construction time is limited;

[0005] 2. During the pilot hole drilling and hole expansion stages, the mud closed circulation effect is poor and the drill is prone to "mud holding". Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a land-to-sea directional drilling construction method, which can solve the problems of complex construction operation and limited construction time in the prior art.

[0007] In order to achieve the above and other purposes, the present invention is implemented by including the following technical solutions: The present invention proposes a land-to-sea directional drilling construction method, including

[0008] Step 1: Exploring the geology, and determining the land entry point, offshore excavation point and path based on the exploration results;

[0009] Step 2: According to the land entry point, sea exit point and path, guide hole drilling and hole expansion construction are carried out from land to sea, and after completion, the pull-back drill rod and hole expander in the guide hole are retained;

[0010] Step 3: After the steel pipe is welded and tested on land and has passed the acceptance inspection, the embankment-piercing construction is carried out from the land entry point to the offshore exit point.

[0011] In one embodiment, the dike-piercing construction specifically includes the following steps:

[0012] The qualified steel pipes are hoisted to the construction area on land, and the lifting ship set up at sea is positioned in advance at a straight extension section 10 meters away from the offshore excavation point; the lifting ship is equipped with a drilling rig;

[0013] On land, connecting the tail of the steel pipe to one end of the pullback drill pipe;

[0014] On the lifting vessel, connecting the other end of the pull-back drill rod to the drilling rig;

[0015] When the steel pipe passes through the dike, a crane is used to connect the pulling cable in the middle of the steel pipe to assist in controlling the curvature of the steel pipe;

[0016] After the penetration of the dike is completed, divers will go into the water to check the situation of the steel pipe at the unearthed point at sea and mark the exact position of the tail of the steel pipe.

[0017] In one embodiment, the reamer is provided on one end of the pullback drill rod.

[0018] In one embodiment, in the step 2, the mud formula is adjusted according to the mud properties measured in real time; the mud formula is prepared using a fresh water source, and the fresh water source is flood water at the construction site.

[0019] In one embodiment, a mud laboratory is established at the construction site to monitor the mud performance parameters in step 2 throughout the process, wherein the performance parameters include base fluid viscosity, mud density, mud pressure in the hole, rheology, shear force and carrying capacity.

[0020] In one embodiment, the construction method further includes step 4, disposing of waste mud generated during the construction.

[0021] In one embodiment, the waste mud includes mud sand separated when the mud is recovered and mud left over from the construction.

[0022] In one embodiment, the mud and sand are stored in a storage area at the construction site, and the storage area is treated to prevent seepage.

[0023] In one embodiment, after all construction is completed, the remaining construction mud and the mud and sand in the storage site are solidified with cement and then transported to a landfill; during transportation, the transport vehicle is sealed and covered.

[0024] In one embodiment, the offshore portion of the residual construction mud is directly solidified with cement on a lifting vessel, and after solidification, it is bagged and transported to land for treatment; or the offshore portion of the residual construction mud is transported to land by a liquid transport ship and then solidified with cement.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention provides a new method for penetrating the dike from the land entry point to the sea exit point, which significantly simplifies the traditional submarine cable laying process. In this way, there is no need to deploy multiple auxiliary ships at sea to perform complex operations, which not only reduces the demand for equipment and personnel, but also reduces the operating cost. More importantly, this method has no special restrictions on the operating time. Compared with the prior art, the entire construction process of the present invention is simpler, more flexible and efficient, and can better adapt to different environmental conditions and project progress requirements;

[0027] 2. The present invention can realize the dike-crossing operation from land to sea by setting a lifting ship with a drilling rig on the sea; setting a crane on land to pull the steel pipe plays a key role in assisting in controlling the curvature of the steel pipe, ensuring that the submarine cable goes smoothly along the path when passing through the dike; this coordination mechanism at both ends of the sea and land not only enhances the safety and reliability of the construction, but also improves the overall quality of the project, ensuring the smooth completion of the dike-crossing operation;

[0028] 3. The present invention uses fresh water to prepare mud, and dynamically adjusts the performance of the mud according to the actual chip return situation. Through the fine control of the rheological properties of the mud, its shear force can be effectively improved, and the carrying capacity of the mud can be enhanced, thereby avoiding the common problem of "mud holding the drill". In turn, the resistance generated by drilling is reduced, and the drilled hole is unobstructed, the transmission of thrust and torque is completed smoothly, and the progress of the next process is effectively guaranteed;

[0029] 4. The method of disposing waste mud of the present invention can ensure that the entire construction process meets environmental protection requirements and minimize the impact on the surrounding marine ecology.

[0030] In summary, the present invention not only simplifies the construction process and improves the project quality, but also fully considers the requirements of environmental protection, representing an important advancement in submarine cable laying technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a schematic flow chart of a land-to-sea directional drilling construction method of the present invention.

[0032] Figure 2 Shown is a schematic diagram of the directional drilling construction path of the present invention.

[0033] Figure 3AShown is a construction schematic diagram of the guide hole drilling in the present invention.

[0034] Figure 3B Shown is a construction schematic diagram of the guide hole expansion in the present invention.

[0035] Figure 3C It shows a schematic diagram of the construction of steel pipe passing through the dike in the present invention. DETAILED DESCRIPTION

[0036] The embodiment of the present invention solves the problems of complicated construction operation, limited construction time, leakage and "mud holding the drill" during the drilling and expansion of the guide hole in the prior art by providing a land-to-sea directional drilling construction method.

[0037] Below, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments of the present invention. It should be understood that the present invention is not limited to the example embodiments described herein. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0038] The overall idea of ​​the technical solution provided by the present invention is as follows: A land-to-sea directional drilling construction method, comprising:

[0039] Step 1: Exploring the geology, and determining the land entry point, offshore excavation point and path based on the exploration results;

[0040] Step 2: According to the land entry point, sea exit point and path, guide hole drilling and hole expansion construction are carried out from land to sea, and after completion, the pull-back drill rod and hole expander in the guide hole are retained;

[0041] Step 3: After the steel pipe is welded and tested on land and has passed the acceptance inspection, the embankment-piercing construction is carried out from the land entry point to the offshore exit point.

[0042] The main idea is to provide a new method for construction through the dike from the land entry point to the sea exit point, which significantly simplifies the traditional submarine cable laying process. In this way, there is no need to deploy multiple auxiliary ships at sea to perform complex operations, which not only reduces the demand for equipment and personnel, but also reduces operating costs. More importantly, this method has no special restrictions on operating time. Compared with the prior art, the entire construction process of the present invention is simpler, more flexible and more efficient, and can better adapt to different environmental conditions and project schedule requirements.

[0043] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below.

[0044] like Figure 1-Figure 3C As shown, the present invention provides a land-to-sea directional drilling construction method, which plans to install major construction equipment including a drilling rig and its supporting equipment, such as a crane, near a land entry point 101; use a lift ship 200 as a construction platform at sea, install a drilling rig 210, etc. on the lift ship 200, and set an offshore support 300 between the lift ship 200 and the offshore excavation point 102 for pulling steel pipes. Specifically, the land-to-sea directional drilling construction method includes

[0045] Step 1: Exploring the geology, and determining the land entry point 101, the offshore excavation point 102 and the path 103 according to the exploration results;

[0046] Specifically, the purpose of the geological survey is to understand the topographical characteristics, geological conditions and hydrological conditions of the construction stratum, and to release the installation position lines of each section of the drilling rig, the specific axis positions and elevations of the two ends of the pipeline according to the pipeline axis required by the construction, mark the axis and elevation in the computer software, and design detailed guidance data. The path 103 selects the submarine cable laying path with the least impact on the environment. At the same time, the process parameters of each stage of construction can be determined according to the exploration results, such as selecting appropriate drilling equipment, appropriate mud formula, drill rod entry angle and drilling speed.

[0047] Step 2: According to the land entry point 101, the offshore exit point 102 and the path 103, the guide hole is drilled and expanded from land to sea, and after completion, the pull-back drill rod 107 and the reamer 106 in the guide hole 104 are retained;

[0048] Specifically, the drilling direction is set using a guidance system, which can be based on magnetic positioning or gyroscope technology to ensure that the drill bit 1051 of the guide drill rod 105 moves along the predetermined path 103. A small diameter guide hole 104 is initially drilled. Once the guide hole 104 is completed, the drill bit 1051 of the guide drill rod 105 is connected to one end of the reamer 106, and the other end of the reamer 106 is connected to the pull-back drill rod 107 for pull-back reaming. During the reaming process, the reaming speed and mud pressure are determined according to the formation conditions and the slurry discharge conditions. Attention should be paid to maintaining mud circulation to help carry rock cuttings and stabilize the hole wall to ensure the reaming quality.

[0049] Since the configuration of the mud is not fixed during the entire construction process, it must be adjusted according to the specific construction conditions. In this embodiment, a mud laboratory is pre-established at the construction site to monitor the mud performance parameters throughout the process, including base liquid viscosity, mud specific gravity, mud pressure in the hole, rheology, shear force and carrying performance. During the pilot hole drilling and hole expansion construction process, firstly, based on the construction experience, the field and laboratory test results of the mud, an environmentally friendly mud with low specific gravity, low water loss, high chip carrying capacity, high fluidity, high wall protection, little influence by seawater, and no influence on seawater is selected; then the mud formula is adjusted according to the specific construction conditions.

[0050] Specifically, in order to ensure the performance of the mud, fresh water sources are used to prepare the mud, and flood water at the construction site is used as a fresh water source. In addition, due to the good hydration effect of bentonite, the clay particles adsorb a thicker hydration film, and the free water in the mud system will be greatly reduced, so the water loss of bentonite mud is much lower than that of inferior soil. The mud system of this embodiment adopts bentonite, which can reduce the water loss of the mud and enhance the water sensitivity of the rock and soil of the well wall. Further, the free water in the mud system is actually the base mud that is filtered into the formation. The higher its viscosity, the lower the rate of infiltration into the formation. Therefore, it is necessary to increase the viscosity of the base fluid when preparing the mud. Furthermore, the pressure difference between the mud pressure in the hole and the fluid in the formation is the driving force for the mud to lose water. Reducing the pressure difference as much as possible during the entire construction process and maintaining balanced drilling are effective measures to reduce water loss.

[0051] Step 3: After the steel pipe 108 is welded and tested on land and passed the inspection, the embankment-penetrating construction is carried out from the land entry point 101 to the offshore exit point 102; specifically, the embankment-penetrating construction includes the following steps:

[0052] The qualified steel pipe 108 is hoisted to the construction area on land, and the lifting ship 200 set at sea is positioned in advance at a straight extension section 10 meters outward from the offshore excavation point 102; the lifting ship 200 is provided with a drilling rig 210;

[0053] On land, after the hole expansion is completed, the guide drill rod 105 is removed, and the tail of the qualified steel pipe 108 is connected to one end of the hole expander 106; the other end of the hole expander 106 is still connected to one end of the pullback drill rod 107;

[0054] On the lifting vessel 200, the other end of the pull-back drill rod 107 is connected to the drilling rig 210;

[0055] When the steel pipe 108 passes through the dike, a crane is used to connect the pulling cable in the middle of the steel pipe 108. The pulling cable can be made of nylon to assist in controlling the curvature of the steel pipe 108.

[0056] After the penetration of the dike is completed, a diver goes into the water to check the situation of the steel pipe 108 at the unearthed point 102 at sea and marks the exact position of the tail of the steel pipe 108.

[0057] During the entire process of the steel pipe 108 passing through the dike, the pulling back speed is controlled according to the pulling back force displayed by the drilling rig 210, and the mud ratio is adjusted according to the geological changes during the process of the steel pipe 108 passing through the dike.

[0058] Step 4: Dispose of the waste mud generated during construction.

[0059] Specifically, the waste mud includes mud and sand separated when recycling mud during the construction process, as well as residual construction mud left after the construction is completed. The mud and sand generated during the construction process can be temporarily stored in a stacking site at the construction site, and the stacking site is treated for seepage isolation. The residual construction mud left after the construction is completed can be solidified by adding cement together with the mud and sand in the stacking site, and transported to a local landfill after complying with environmental protection requirements and obtaining the consent of relevant departments. During transportation, the transport vehicle needs to be sealed and covered to ensure that the solidified waste mud does not spill on the transportation route.

[0060] In addition, waste mud at sea can be directly solidified with cement on the lifting ship 200, and then packed into bags and transported to land for treatment; it can also be transported to land by a liquid transport ship and then solidified with cement.

[0061] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value. The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A land-to-sea directional drilling construction method, characterized in that: include Step 1: Exploring the geology, and determining the land entry point, offshore excavation point and path based on the exploration results; Step 2: According to the land entry point, sea exit point and path, guide hole drilling and hole expansion construction are carried out from land to sea, and after completion, the pull-back drill rod and hole expander in the guide hole are retained; Step 3: After the steel pipe is welded and tested on land and has passed the acceptance inspection, the embankment-piercing construction is carried out from the land entry point to the offshore exit point.

2. The land-to-sea directional drilling construction method according to claim 1, characterized in that: The embankment-crossing construction specifically includes the following steps: The qualified steel pipes are hoisted to the construction area on land, and the lifting ship set up at sea is positioned in advance at a straight extension section 10 meters away from the offshore excavation point; the lifting ship is equipped with a drilling rig; On land, connecting the tail of the steel pipe to one end of the pullback drill pipe; On the lifting vessel, connecting the other end of the pull-back drill rod to the drilling rig; When the steel pipe passes through the dike, a crane is used to connect the pulling cable in the middle of the steel pipe to assist in controlling the curvature of the steel pipe; After the penetration of the dike is completed, divers will go into the water to check the situation of the steel pipe at the unearthed point at sea and mark the exact position of the tail of the steel pipe.

3. The land-to-sea directional drilling construction method according to claim 2, characterized in that: The reamer is arranged on one end of the pullback drill rod.

4. The land-to-sea directional drilling construction method according to claim 1, characterized in that: In the step 2, the mud formula is adjusted according to the mud properties measured in real time; the mud formula is prepared using a fresh water source, and the fresh water source is flood water at the construction site.

5. The land-to-sea directional drilling construction method according to claim 4, characterized in that: A mud laboratory is established at the construction site to monitor the mud performance parameters in step 2 throughout the entire process, wherein the performance parameters include base fluid viscosity, mud specific gravity, mud pressure in the hole, rheology, shear force and carrying capacity.

6. The land-to-sea directional drilling construction method according to claim 1, characterized in that: The method also includes step 4, disposing of the waste mud generated during the construction.

7. The land-to-sea directional drilling construction method according to claim 6, characterized in that: The waste mud includes mud sand separated when the mud is recovered and the remaining mud during construction.

8. The land-to-sea directional drilling construction method according to claim 7, characterized in that: The mud and sand are stored in a storage area at the construction site, and the storage area is treated for seepage isolation.

9. The land-to-sea directional drilling construction method according to claim 8, characterized in that: After all construction is completed, the remaining construction mud and the mud and sand in the storage site are solidified with cement and then transported to the landfill; during transportation, the transportation vehicle is sealed and covered.

10. The land-to-sea directional drilling construction method according to claim 9, characterized in that: The offshore part of the residual mud from the construction is directly solidified with cement on a lifting vessel, and after solidification, it is bagged and transported to land for treatment; or the offshore part of the residual mud from the construction is transported to land by a liquid transport ship and then solidified with cement.

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