A method for selecting temporary ship-lifting position for a jack-up platform ferry route

Abstract

The present invention provides a method for selecting a temporary ship lift location for a jack-up platform ferry route, comprising the following steps: planning an initial ferry route; determining a turning point; determining a final ferry route; selecting a ship lift node along the ferry route; selecting a well site surrounding the node; identifying the well site's characteristics and risks; determining a safe ship lift location within the well site; determining a backup well site; and determining a safe ship lift location at the backup well site. This method helps a jack-up platform avoid the effects of inclement weather during towing, ensuring the safety of the jack-up platform's towing operations, large-scale facilities, and personnel, and promoting offshore oilfield exploration and development.

Description

Technical Field

[0001] The invention belongs to the technical field of towing operations of a self-elevating platform in an offshore oil field, and in particular relates to a method for selecting a temporary ship-lifting position for a self-elevating platform ferry route. Background Art

[0002] With the increasing development and exploitation of oil fields, most oilfield development is now being completed using jack-up rigs. Jack-up rigs are the most important mobile drilling rigs in offshore oilfield development. Towed by tugboats, jack-up rigs are moved from one well location to another, and from one production platform to another, completing exploration and production operations.

[0003] Due to the varying lengths of towing routes and the uncontrollable risks of jack-up rigs during their passage, such as weather fluctuations and water obstacles, jack-up rigs face numerous complexities during towing. These include dangerous situations such as disconnection of the towline from the towed jack-up rig, loss of control of the jack-up rig, and even the sinking of the jack-up rig. Towing is a large-scale joint operation involving both the large-scale jack-up rig and the tugboat, as well as personnel safety. Therefore, towing route planning requires advance research and analysis to determine weather and sea conditions, and to develop detailed contingency plans to prevent major accidents.

[0004] At present, towing route planning is mainly based on the towing captain's navigation experience. It does not fully consider the avoidance of water obstacles during towing, regulations of offshore oil mining areas, and the impact of local severe weather. As a result, the towing operation has a greater potential risk, causing great safety hazards to personnel safety and large facilities, and affecting the progress of oil field exploration and development. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a method for selecting a temporary ship lifting position for a jack-up platform's ferry route. The method helps the jack-up platform avoid the influence of bad weather during the towing process, ensures the safety of the jack-up platform's towing operation, the safety of large facilities and personnel, and promotes the exploration and development of offshore oil fields.

[0006] The present invention provides a method for selecting a temporary ship lift position for a jack-up platform ferry route, comprising the following steps:

[0007] S1: Plan the initial ferry route;

[0008] S2: Determine the heading turning point;

[0009] S3: Determine the final ferry route;

[0010] S4: Select the ship lift node on the ferry route;

[0011] S5: Select the well sites around the node;

[0012] S6: Identify wellsite properties and wellsite risks;

[0013] S7: Determine the safe position for ship lifting within the well site;

[0014] S8: Determine the backup well site;

[0015] S9: Determine the safe ship lifting position at the backup well site.

[0016] Furthermore, the S1 includes the following steps:

[0017] S11: The initial navigation route is the route between the starting well location TO and the target well location TF, and the length of the initial navigation route is measured;

[0018] S21: Mark and record water obstacles on the initial ferry route and within 3 nautical miles around the initial ferry route, weather forecast information, and other factors affecting the ferry.

[0019] Furthermore, the S2 includes the following steps:

[0020] S21: When the water obstacle is located directly in front of the initial navigation route, the turning point is set at a position 2.5 nautical miles away from the water obstacle, and the general direction of the turning is consistent with the target well location TF;

[0021] S22: When the water obstacle is located on one side of the initial ferry route and the distance is less than 2.5 nautical miles, a 2.5 nautical mile long perpendicular line segment is drawn from the coordinate point of the water obstacle to the initial ferry route, and the foot of the perpendicular line is the turning point;

[0022] S23: When the water obstacle is located on both sides of the initial ferry route, a vertical line segment is drawn toward the initial ferry route with the coordinate point of the water obstacle that is convenient for turning and close to the turning side as the starting point, and the vertical line segment is extended in the opposite direction of the vertical line segment with the foot of the vertical line as the starting point. The extension length is equal to the length of the vertical line plus 2.5 nautical miles. The other end point of the line segment is the turning point.

[0023] S24: Mark the turning points as WPT1, WPT2, WPT3, WPT4, and WPTN;

[0024] S25: Entering the coordinates of the turning point into a navigation guidance system.

[0025] Furthermore, the final ferry route is a line connecting the starting well location TO, the turning points WPT1 to WPTN, and the target well location TF. The final ferry route is the total voyage distance of the jack-up platform, and the total voyage distance is an important basis for determining the towing plan and towing time.

[0026] Furthermore, the S4 includes the following steps:

[0027] S41: selecting a ship lift node according to the total voyage, weather, and wind and waves;

[0028] S42: The ship lift nodes are arranged around the turning points or on both sides of a line connecting any two turning points;

[0029] S43: The distance between the ship lift node and the turning point or the final ferry route is no more than 1 nautical mile.

[0030] Furthermore, during the towing time period required for the total voyage, the towing weather is less than or equal to level 7 on the Beaufort scale, and the wave height is less than 4 meters.

[0031] Furthermore, a suitable well site is selected within 1 nautical mile of the node. The suitable well site is a well site where the seabed topography and shallow profile do not have hazardous geological features, and the soil data obtained from engineering geology predicts that the jack-up platform can safely insert piles. When there are multiple suitable well sites within 1 nautical mile of the final ferry route, the well site closest and in the direction of travel is selected as the preferred well site.

[0032] Furthermore, the S7 includes the following steps:

[0033] S71: The safe ship lift position is far away from the well site risk and more than 200 meters away from the well site risk boundary;

[0034] S72: For surveyed and drilled exploratory well sites, avoid the well center and be at least 200 meters away from the old pile shoe pit, and at least 200 meters away from the risk boundary of the well site;

[0035] S73: For surveyed but undrilled exploratory well sites, the site must be more than 500 meters away from the well site center and more than 200 meters away from the well site risk boundary.

[0036] Furthermore, the ship lifting position satisfies the safety of the pile legs of the jack-up platform, and the predicted pile insertion depth of the jack-up platform at the ship lifting position is less than or equal to the maximum allowable pile insertion depth in the jack-up platform operation manual.

[0037] Furthermore, the backup well site includes a section of the ferry route that is prone to danger, which is a dangerous section for ships sailing at sea. It also includes a section where the ferry route is within a temporary military exercise area, and the jack-up platform needs to be evacuated outside the boundary of the military exercise area.

[0038] The advantages and positive effects of the present invention are:

[0039] The present invention overcomes the shortcomings of the existing technology. Conventional towing route planning is based on the captain of the towing ship at sea making the towing route based on navigation experience. It does not fully consider the avoidance of water obstacles during towing, the regulations of offshore oil mining areas, and the impact of local severe weather. This results in great potential risks in towing operations, posing a great safety hazard to personnel and large facilities, affecting the progress of oil field exploration and development, and exposing the shortcomings of incomplete consideration of risk factors and unreasonable towing routes. The route planning of the present invention is more scientific and the route calculation is more accurate. This method helps the jack-up platform avoid the influence of severe weather during towing and ensure the safety of the jack-up platform towing operation. This method is conducive to avoiding water obstacles during towing of the jack-up platform, ensuring the safety of large facilities and personnel, and promoting the progress of offshore oil field exploration and development. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is an overall flow chart of an embodiment of the present invention.

[0041] Figure 2 Schematic diagram of selecting turning points on the same side of water obstacles according to an embodiment of the present invention.

[0042] Figure 3 Schematic diagram of the selection of turning points on both sides of a water obstacle according to an embodiment of the present invention.

[0043] Figure 4 Schematic diagram of temporary ship lift location selection and well site location according to an embodiment of the present invention.

[0044] Figure 5-7 It is a route diagram in a specific embodiment of the present invention.

[0045] Figure 8-10 It is a schematic diagram of selecting well sites around a node in a specific embodiment of the present invention.

[0046] Figure 11 It is a schematic diagram of determining a safe ship lift position within a well site in a specific embodiment of the present invention.

[0047] Figure 12 It is a schematic diagram of the selection of a spare well site and a safe ship lift position in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0050] like Figure 1 As shown, a method for selecting a temporary ship lifting position for a jack-up platform ferry route includes the following steps:

[0051] S1: Planning the initial ferry route. The initial ferry route planning should be done on an authoritative electronic nautical chart or a nautical chart provided by an authoritative department, i.e., the Navigation Assurance Department. Specifically, S1 includes the following steps.

[0052] S11: The initial navigation route is the route between the starting well location TO and the target well location TF, which is generally a straight line segment connecting the two points. The length of the initial navigation route is measured in nautical miles.

[0053] S21: Mark and record the length of the initial ferry route, any water obstacles on and within 3 nautical miles of the initial ferry route, weather forecast information, and other factors affecting the ferry. Specifically, water obstacles include jackets, platforms, wind turbine facilities, etc. If the weather forecast predicts strong winds of Beaufort Force 8 or higher within the next 24 hours, select the nearest planned ship lift point for the ferry lift before the wind arrives.

[0054] S2: Determine a heading turning point. Specifically, S2 includes the following steps.

[0055] S21: When one or more water obstacles are located directly in front of the initial navigation route, the turning point is set at a position 2.5 nautical miles away from the water obstacles, and the general direction of the turning must be consistent with the target well location TF.

[0056] S22: Figure 2 As shown, when one or more water obstacles are located on one side of the initial ferry route and the distance is less than 2.5 nautical miles, a 2.5 nautical mile long vertical line segment is drawn from the coordinate point of the water obstacle to the initial ferry route, and the foot of the vertical line is the turning point.

[0057] S23: If Figure 3 As shown in the figure, when one or more water obstacles are located on both sides of the initial ferry route, a vertical line segment is drawn toward the initial ferry route with the coordinate point of the water obstacle that is convenient for turning and close to the turning side as the starting point, and the vertical line segment is extended in the opposite direction of the vertical line segment with the foot of the vertical line as the starting point. The extension length is equal to the length of the vertical line plus 2.5 nautical miles. The other end point of the line segment is the turning point.

[0058] S24: Mark the turning points as WPT1, WPT2, WPT3, WPT4, and WPTN.

[0059] S25: Enter the coordinates of the turning point into the navigation guidance system.

[0060] S3: Determine the final ferry route. The final ferry route is the line connecting the starting well location TO, the turning points WPT1 to WPTN, and the target well location TF. The final ferry route is the total voyage distance of the jack-up platform. The total distance is an important basis for determining the towing plan and towing time. The final ferry route includes the heading and single-segment distance.

[0061] S4: Selecting a ship lift node on the ferry route. Specifically, S4 includes the following steps.

[0062] S41: The main factors to consider when selecting a ship lift point include the total voyage distance, weather, wind, waves, and currents. Therefore, the ship lift point should be selected based on the total voyage distance, weather, and wind and waves. If there is only one temporary ship lift point or none on the final ferry route, it is necessary to check the towing weather conditions in advance. The total voyage distance and the required towing period must be within good weather conditions, meaning wind speeds of less than or equal to level 7 on the Beaufort scale and waves less than 4 meters high.

[0063] S42: The ship lift nodes can be arranged around the turning points or on both sides of the line connecting any two turning points.

[0064] S43: The distance between the ship lift node and the turning point or the final ferry route shall not exceed 1 nautical mile. Specifically, the number of ship lift nodes should not exceed 3.

[0065] S5: Select well sites around the node, choosing suitable well sites within 1 nautical mile of the node. Specifically, a suitable well site is one where the seafloor topography and shallow profiles are free of hazardous geological features, and where soil data obtained from engineering geology predicts safe pile insertion for a jack-up platform. If multiple suitable well sites exist within 1 nautical mile of the final route, the closest well site in the forward direction is selected as the preferred well site. Also, pay attention to the timeliness of the well site survey data when selecting well sites around the node. Seafloor topography surveys older than one year must be resurveyed.

[0066] S6: Identify wellsite characteristics and risks. Specifically, there are two types of wellsite characteristics: one where a wellsite survey has been conducted and the jack-up rig has been deployed and drilling has commenced; the other where a wellsite survey has been conducted but the jack-up rig has not yet been deployed and drilling has commenced. Wellsite risks include, but are not limited to, faults, paleochannels, shallow gas formations, and anomalous reflections.

[0067] S7: Determine the safe position for lifting the ship within the well site. The position for lifting the ship must meet the safety requirements for the jack-up platform leg pile insertion. Specifically, the predicted depth of the jack-up platform pile insertion at the position for lifting the ship must be less than or equal to the maximum allowable pile insertion depth specified in the jack-up platform operation manual. Figure 4 As shown, TO represents the starting well position, TF represents the target well position, and specifically, S7 includes the following steps.

[0068] S71: The safe ship lift location is far away from the well site risk and more than 200 meters away from the well site risk boundary.

[0069] S72: For surveyed and drilled exploratory well sites, avoid the well center and be more than 200 meters away from the old pile shoe pit, and at least 200 meters away from the risk boundary of the well site.

[0070] S73: For surveyed but undrilled exploratory well sites, the site must be at least 500 meters away from the well center and at least 200 meters away from the well site risk boundary.

[0071] S8: Determine a backup well site. Specifically, backup well sites include two scenarios: one is located in a dangerous section of the ferry route, which is a known dangerous section for ships at sea; the other is located within a temporary military exercise area, where the jack-up platform needs to be evacuated outside the military exercise area. The specific method for selecting a backup well site is the same as in S5.

[0072] S9: Determine a safe jack-up location for the backup well site. Specifically, the process for determining a safe production location for the backup well site is the same as S7. Selecting a safe jack-up location for the backup well site is a safety measure, although one to three locations may be planned along the jack-up route. Their use should be minimized.

[0073] The technical solution of the present invention is further described below with reference to specific embodiments, including the following steps:

[0074] S1: A jack-up platform X travels from starting well A to target well B. The straight-line distance between starting well A and target well B is 65 nautical miles.

[0075] S2: From the electronic nautical chart on the ship information network, it can be seen that six groups of offshore platforms will be encountered or crossed when traveling from exploration well A to exploration well B. Therefore, six turning points WPT1 to WPT6 are set, and the coordinates of exploration wells A and B and WPT1 to WPT6 are entered into the navigation guidance system. The specific data are shown in Table 1.

[0076] Table 1 Turning point WPT1~WPT6 and total voyage data

[0077]

[0078] S3: Connect exploration well A, WPT1~WPT6, and exploration well B, such as Figure 5-7 As shown, the total measured distance was 75.8 nautical miles, which is 10.8 nautical miles more than the straight-line distance.

[0079] S4: Selection of ship lift nodes on the ferry route. Based on comprehensive considerations of the total voyage distance, the season, sea weather, and sea conditions at the time of towing, two nodes were selected for this towing. The first node was near WPT3, and the second node was near WPT6.

[0080] S5: If Figure 8-10 As shown, near the first ship lift node WPT3, the investigated exploration wells E1 and E2 were found. The shallow section of the E1 well has no hazardous geological features, and the jack-up platform X can safely drive piles at this well location. The center of the E2 well has an ancient river channel and is not suitable for a temporary ship lift point. Therefore, the E1 well was selected as the temporary ship lift point. Figure 10 The horizontal axis is the ultimate pile shoe load, in MN, and the vertical axis is the depth of the pile shoe tip into the mud below the seabed surface, in m.

[0081] S6: The E1 well site is a site surveyed but unexplored well location with no risk features such as faults, paleochannels, shallow gas, and abnormal reflections.

[0082] S7: As Figure 11 As shown, Well E1 is a well location that has been investigated but not drilled, but the well site has no hazardous geological features. Therefore, it is only necessary to be in the direction of travel and more than 500 meters away from the center of the well site. The direction of travel is 132° southeast according to the planned route.

[0083] S8: Near the first ship lift node WPT6, it was discovered that the exploration wells F1, F2, and F3 had been investigated.

[0084] S9: Well F1 has a paleochannel in its shallow section, but it's 700 meters from the well center, making it too far for Jack-up Platform X to drive piles there safely. Well F2 has no hazardous geological conditions near its center, making it safe for Jack-up Platform X to drive piles there. Well F3 has shallow gas formations within 300 meters of its center, and Jack-up Platform X's piles would be too deep to drive piles there, making it unsafe and unsuitable for a temporary vessel lift. Therefore, Well F2 was selected as the temporary vessel lift site, located 500 meters from F2's center, 160° from the well. Well F1 was selected as the backup vessel lift site, located 500 meters from F1's center, 160° from the well center.

[0085] The advantages and positive effects of the present invention are:

[0086] The present invention overcomes the shortcomings of the existing technology. Conventional towing route planning is based on the captain of the towing ship at sea making the towing route based on navigation experience. It does not fully consider the avoidance of water obstacles during towing, the regulations of offshore oil mining areas, and the impact of local severe weather. This results in great potential risks in towing operations, posing a great safety hazard to personnel and large facilities, affecting the progress of oil field exploration and development, and exposing the shortcomings of incomplete consideration of risk factors and unreasonable towing routes. The route planning of the present invention is more scientific and the route calculation is more accurate. This method helps the jack-up platform avoid the influence of severe weather during towing and ensure the safety of the jack-up platform towing operation. This method is conducive to avoiding water obstacles during towing of the jack-up platform, ensuring the safety of large facilities and personnel, and promoting the progress of offshore oil field exploration and development.

[0087] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for selecting a temporary ship-lifting location for a jack-up platform ferry route, characterized by: The following steps are included: S1: Planning the initial ferry route, said S1 includes the following steps: S11: The initial navigation route is the route between the starting well location TO and the target well location TF, and the length of the initial navigation route is measured; S12: Mark and record water obstacles on the initial ferry route and within 3 nautical miles around the initial ferry route, weather forecast information and other factors affecting the ferry; S2: Determine the heading turning point, S2 includes the following steps: S21: When the water obstacle is located directly in front of the initial navigation route, the turning point is set at a position 2.5 nautical miles away from the water obstacle, and the general direction of the turning is consistent with the target well location TF; S22: When the water obstacle is located on one side of the initial ferry route and the distance is less than 2.5 nautical miles, a 2.5 nautical mile long perpendicular line segment is drawn from the coordinate point of the water obstacle to the initial ferry route, and the foot of the perpendicular line is the turning point; S23: When the water obstacle is located on both sides of the initial ferry route, a vertical line segment is drawn toward the initial ferry route with the coordinate point of the water obstacle that is convenient for turning and close to the turning side as the starting point, and the vertical line segment is extended in the opposite direction of the vertical line segment with the foot of the vertical line as the starting point. The extension length is equal to the length of the vertical line plus 2.5 nautical miles. The other end point of the line segment is the turning point. S24: Mark the turning points as WPT1, WPT2, WPT3, WPT4, and WPTN; S25: Entering the coordinates of the turning point into a navigation guidance system; S3: Determine the final ferry route; S4: Select the ship lift node on the ferry route; S5: Select the well sites around the node; S6: Identify wellsite properties and wellsite risks; S7: Determine the safe position for ship lifting within the well site; S8: Determine the backup well site; S9: Determine the safe ship lifting position at the backup well site.

2. The method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to claim 1, characterized in that: The final ferry route is the line connecting the starting well location TO, the turning points WPT1-WPTN and the target well location TF. The final ferry route is the total voyage distance of the jack-up platform. The total voyage distance is an important basis for determining the towing plan and towing time.

3. The method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to claim 2, characterized in that: Said S4 comprises the following steps, S41: selecting a ship lift node according to the total voyage, weather, and wind and waves; S42: The ship lift nodes are arranged around the turning points or on both sides of a line connecting any two turning points; S43: The distance between the ship lift node and the turning point or the final ferry route is no more than 1 nautical mile.

4. A method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to claim 2 or 3, characterized in that: During the towing time period required for the total voyage, the towing weather is less than or equal to level 7 on the Beaufort scale and the wave height is less than 4 meters.

5. A method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to any one of claims 1 to 3, characterized in that: A suitable well site is selected within 1 nautical mile of the node. The suitable well site is one where the seabed topography and shallow profile do not have hazardous geological features, and where soil data obtained from engineering geology predicts that the jack-up platform can safely insert piles. If multiple suitable well sites exist within 1 nautical mile of the final ferry route, the well site closest and in the direction of travel is selected as the preferred well site.

6. A method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to any one of claims 1 to 3, characterized in that: Said S7 comprises the following steps, S71: The safe ship lift position is far away from the well site risk and more than 200 meters away from the well site risk boundary; S72: For surveyed and drilled exploratory well sites, avoid the well center and be at least 200 meters away from the old pile shoe pit, and at least 200 meters away from the risk boundary of the well site; S73: For surveyed but undrilled exploratory well sites, the site must be more than 500 meters away from the well site center and more than 200 meters away from the well site risk boundary.

7. The method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to claim 6, characterized in that: The ship lifting position satisfies the safety of the pile insertion of the jack-up platform legs, and the predicted pile insertion depth value of the jack-up platform at the ship lifting position is less than or equal to the maximum allowable pile insertion depth in the jack-up platform operation manual.

8. A method for selecting a temporary ship-lifting position for a jack-up platform ferry route according to any one of claims 1 to 3, characterized in that: The backup well site includes a section of the ferry route that is prone to danger, which is a dangerous section for ships sailing at sea. It also includes a section where the ferry route is within a temporary military exercise area, and the jack-up platform needs to be evacuated beyond the boundary of the military exercise area.

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