Double-wellhead suction pile simulation bearing test device and method

Abstract

The invention discloses a double-wellhead suction pile simulation bearing test device and method. The device comprises a sealed container, a suction pile model, a negative pressure device, a pressurizing device, a vertical loading assembly, a horizontal loading assembly and a detection assembly. The sealed container is filled with a soil layer and a preset depth water body to simulate a deep-sea shallow soft stratum and a seawater environment; the suction pile model is arranged on a soil layer, and a first wellhead, a second wellhead and a suction port are symmetrically formed in the top of the suction pile model. The negative pressure device is connected with the suction port to provide negative injection pressure, and the pressurizing device increases the internal pressure of the container to simulate deep sea hydrostatic pressure. The vertical loading assembly applies controllable downward pressure through the second wellhead and simulates the gravity of the drilling equipment; and the horizontal loading assembly applies irregularly changed transverse load through the second wellhead to simulate wind wave flow environment force. The detection assembly monitors the displacement and inclination angle of the suction pile in real time. According to the scheme, the bearing characteristics of the double-wellhead suction pile under the deep sea complex load can be accurately reproduced, and a key test basis is provided for the structural design of the double-wellhead suction pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploitation, and particularly relates to a double-wellhead suction pile simulation bearing test device and method. BACKGROUND

[0002] In the field of deepwater oil and gas resource development, drilling operations in shallow soft strata face the challenge of insufficient bearing capacity of soft seabed pile foundation, which directly affects the stability of the wellhead and the safety of the operation. Suction pile well construction technology, as an effective solution, has been widely used in such geological conditions. This technology significantly improves the bearing capacity and stability of the pile foundation in the seabed by using the principle of suction penetration, providing a reliable guarantee for deepwater drilling and production operations.

[0003] In recent years, in order to improve the operation efficiency, double-wellhead suction pile well construction technology has emerged. The core of this technology is that two wellheads are integrated on the prefabricated suction pile structure, and each wellhead is pre-installed with a guide pipe and a pre-inclined casing. The main technical process includes: the engineering ship transports the prefabricated suction pile to the well site, and then lowers it to the top of the mud line on the seabed by means of a cable, relying on its own weight to initially penetrate; then the suction pump is started to discharge the water and air in the pile, and the internal and external pressure difference formed is used to penetrate the suction pile to the designed depth; then the intermediate casing is drilled, the casing is installed, the well is cemented, and the well control equipment and the riser assembly are installed, laying the foundation for subsequent drilling operations. The significant advantage of the double-wellhead design is that it can install two pre-inclined wellheads at one time, which is equivalent to simultaneously completing the surface batch drilling and pre-inclination operation, greatly simplifying the operation process, especially beneficial to the build-up drilling of subsequent directional wells. According to estimates, it can save about 5-6 days of platform operation time. At the same time, its potential for multi-well commingling is helpful to increase production and efficiency, showing broad application prospects.

[0004] However, the double-wellhead suction pile technology exposes a key technical bottleneck and safety hazard in the implementation process, namely the overall bearing instability risk under non-uniform load. Specifically, during the drilling operation stage, usually one wellhead will be the first to install well control equipment and a riser assembly, while the other wellhead will be in an uninstalled state. This asymmetric load distribution (one side bears significant additional loads such as drilling equipment, riser, etc., while the other side bears relatively small loads) causes the suction pile to bear significant eccentric bending moments and lateral forces. Under the condition of shallow soft strata, this non-uniform load is extremely prone to induce overall tilting deformation of the suction pile, and in severe cases, it may even cause the entire structure to overturn, resulting in the abandonment of the drilled wellbore and causing significant economic losses and safety risks.

[0005] At present, the in-depth research and field application practice of double-well suction pile technology are extremely scarce, and the relevant field of theoretical research literature is rarely published. In particular, the bearing mechanism, instability mode and design method of double-well suction pile under complex non-uniform load have not yet formed a systematic and reliable supporting research result, which constitutes a new technical research field. Limited by the reality conditions of difficult field test and high cost, the existing research mainly relies on numerical simulation means for discussion. However, only numerical simulation often cannot fully and accurately reflect the actual complex seabed conditions and load working conditions, which may lead to the fact that the theoretical design of the structure size of the suction pile cannot meet the actual bearing capacity requirement of the field, and hidden dangers are caused for engineering application.

[0006] Therefore, it is urgent to develop a test device and method capable of effectively simulating the bearing performance of double-well suction pile under non-uniform load. Such device and method are crucial for in-depth understanding of the instability mechanism, verification of design theory, optimization of structure size and evaluation of safety margin, and are essential support for promoting double-well suction pile technology from theory to safe and reliable engineering application. SUMMARY

[0007] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a double-well suction pile simulation bearing test device and method, which aims to provide a test device and method capable of effectively simulating the bearing performance of double-well suction pile under non-uniform load.

[0008] The present application provides a double-well suction pile simulation bearing test device, comprising: a sealed container, the sealed container is used for laying soil layer, water of preset depth and suction pile model, the suction pile model is used for being placed on the soil layer, a first well mouth, a second well mouth and a suction port are opened on the suction pile model, the first well mouth and the second well mouth are symmetrically arranged on the top of the suction pile model about the vertical axis of the suction pile model; a negative pressure device, the negative pressure device is connected with the suction port, and the negative pressure device is used for providing negative pressure in the suction pile model; a pressure device, the pressure device is used for being connected with the sealed container, and the pressure device is used for lifting the pressure in the sealed container; a vertical loading assembly, the vertical loading assembly comprises a first pressure loading mechanism and a first pressure control device, a pressure loading end of the first pressure loading mechanism is drivingly connected with the second well mouth, and the first pressure control device is used for controlling the first pressure loading mechanism to provide downward pressure in the vertical direction for the suction pile model; A horizontal loading assembly, which comprises a second pressure loading mechanism and a second pressure control device, a pressure loading end of the second pressure loading mechanism is in transmission connection with the second wellhead, the second pressure control device is used for controlling the second pressure loading mechanism to provide a horizontal transverse force for the suction pile model, and the transverse force changes irregularly; A detection assembly, which comprises a displacement detection piece and an inclination detection piece, the displacement detection piece is used for detecting the longitudinal displacement of the suction pile model, and the inclination detection piece is used for detecting the inclination angle of the suction pile model.

[0009] According to the double-wellhead suction pile simulation bearing test device provided by the application, the sealing container comprises a box body and a box cover, the box cover is in openable and closable connection with the box body, and the box cover is in sealing connection with the box body when the box cover is closed.

[0010] According to the double-wellhead suction pile simulation bearing test device provided by the application, the suction pile model comprises: A pile body, which is hollow inside and open at the bottom, the first wellhead and the second wellhead are arranged at the top of the pile body, and the axes of the first wellhead and the second wellhead are symmetrical about the axis of the pile body, and the suction port is arranged on the pile body; A prefabricated guide pipe, the first wellhead and the second wellhead are both provided with the prefabricated guide pipe; A pre-inclined casing pipe, the prefabricated guide pipe is provided with the pre-inclined casing pipe.

[0011] According to the double-wellhead suction pile simulation bearing test device provided by the application, the negative pressure device comprises a first air pump and a suction pipe, the first air pump is arranged outside the sealing container, one end of the suction pipe is connected with the air inlet of the first air pump, and the other end of the suction pipe is connected with the suction port of the suction pile model.

[0012] According to the double-wellhead suction pile simulation bearing test device provided by the application, the pressurizing device comprises a second air pump and a pressurizing pipe, the second air pump is arranged outside the sealing container, one end of the pressurizing pipe is connected with the air outlet of the second air pump, and the other end of the pressurizing pipe is in communication with the sealing container.

[0013] According to the double-wellhead suction pile simulation bearing test device provided by the application, the first pressure loading mechanism comprises a first linear driving device and a vertical force transmission rod, the first linear driving device is connected with the sealing container and located above the second wellhead, the vertical force transmission rod is arranged between the first linear driving device and the second wellhead, and the first linear driving device is used for driving the vertical force transmission rod to move in the vertical direction; The second pressure loading mechanism comprises a second linear driving device and a horizontal force transmission rod, the second linear driving device is connected with the sealed container and located at one side of the vertical force transmission rod, one end of the horizontal force transmission rod is connected with the second linear driving device, and the other end is connected with the vertical force transmission rod in a sliding and rotating mode, and the rotating axis and the sliding axis are both collinear with the axis of the vertical force transmission rod.

[0014] According to the application, the detection assembly further comprises a gas pressure detection element.

[0015] The application further provides a double-well suction pile simulation bearing test method, which is implemented based on the double-well suction pile simulation bearing test device. The preset scale ratio is determined, and the size of the double-well suction pile to be simulated, the weight of the double-well suction pile to be simulated, the depth to be reached by the double-well suction pile to be simulated, the data of the in-situ stratum soil, and the hydrostatic pressure value of the position where the double-well suction pile to be simulated is located are obtained, and the data of the in-situ stratum soil at least includes the shear strength, mineral composition, particle size distribution, and stratum particle density of the in-situ stratum soil. The soil layer is prepared based on the preset scale ratio and the data of the in-situ stratum soil, and the soil layer is laid in the sealed container. The size and weight of the suction pile model are determined based on the preset scale ratio and the size and weight of the double-well suction pile to be simulated, the suction pile model is manufactured based on the size and weight of the suction pile model, and the suction pile model is placed at the top center of the test soil sample. The vertical loading assembly and the horizontal loading assembly are connected with the second well of the suction pile model, and the negative pressure device is connected with the suction port of the suction pile model. Water is added in the sealed container, and the depth of the water satisfies that the top of the suction pile model is below the water surface when the suction pile model penetrates to 20 cm from the mud line. Based on the hydrostatic pressure value and the preset scale ratio, the environmental pressure to be reached in the sealed container is calculated, and the pressurizing device is started to make the pressure in the sealed container reach the environmental pressure. Based on the depth to be reached by the double-well suction pile to be simulated and the preset scale ratio, the test depth to be reached by the suction pile model is calculated, the suction pile model penetrates to a certain depth by relying on the self weight, then the negative pressure device is started to perform suction, and under the action of the internal and external pressure difference, the suction pile model continues to penetrate until the test depth is reached. The vertical loading assembly and the horizontal loading assembly are used to apply non-uniform load to the suction pile model, and the displacement detection element and the inclination detection element are used to detect the dynamic response data of the suction pile model under the action of the non-uniform load.

[0016] The double-well suction pile simulation bearing test method provided by the application is characterized in that the weight of the suction pile model is based on the weight of the suction pile model, and the weight of the suction pile model is adjusted by injecting a counterweight material into the suction pile model.

[0017] The double-well suction pile simulation bearing test method provided by the application is characterized in that the soil layer in the suction pile model is prepared based on the preset scale ratio and the data of the in-situ stratum soil, and includes the following steps: The test soil sample is artificially compounded based on the mineral composition, particle size distribution and stratum particle density of the in-situ stratum soil. The test soil sample is weighed based on the thickness of the in-situ stratum soil and the preset scale ratio. The test shear strength of the soil layer is determined based on the shear strength of the in-situ stratum soil and the preset scale ratio, and the following steps are cyclically executed until the shear strength of the soil layer is close to the test shear strength: 50% of the saturated water content is added, and the test soil sample is compressed; 30% of the saturated water content is added, the test soil sample is wrapped with plastic wrap and left to stand for 8 hours, so that the test soil sample is fully watered; The remaining 20% of the saturated water content is added, the test soil sample is wrapped with plastic wrap and left to stand for 8 hours, so that the test soil sample is fully watered.

[0018] The application has the following advantages due to the above technical solutions: The double-well suction pile simulation bearing test device provided by the application comprises a sealed container, a negative pressure device, a pressurizing device, a vertical loading assembly, a horizontal loading assembly and a detection assembly. The sealed container is used for laying soil and water of a preset depth and is used for preventing the suction pile model. The suction pile model is arranged in the sealed container and is used for being placed on the soil. The suction pile model is provided with a first well, a second well and a suction port. The first well and the second well are symmetrically arranged on the top of the suction pile model about the vertical axis of the suction pile model. The negative pressure device is connected with the suction port and is used for providing negative pressure for the inside of the suction pile model. The pressurizing device is used for being connected with the sealed container and is used for increasing the pressure in the sealed container. The vertical loading assembly comprises a first pressure loading mechanism and a first pressure control device. The pressure loading end of the first pressure loading mechanism is drivingly connected with the second well. The first pressure control device is used for controlling the first pressure loading mechanism to provide downward pressure in the vertical direction for the suction pile model. The horizontal loading assembly comprises a second pressure loading mechanism and a second pressure control device. The pressure loading end of the second pressure loading mechanism is drivingly connected with the second well. The second pressure control device is used for controlling the second pressure loading mechanism to provide irregularly changed horizontal force for the suction pile model. The detection assembly comprises a displacement detection piece and an inclination detection piece. The displacement detection piece is used for detecting the longitudinal displacement of the suction pile model. The inclination detection piece is used for detecting the inclination angle of the suction pile model. In the experiment, the soil and water laid in the sealed container are used for simulating the shallow soft stratum and seawater in the deep sea environment. The suction pile model penetrates into the soil to a certain depth by relying on its own gravity, then the negative pressure device provides negative pressure for the inside of the suction pile model, and the suction pile model penetrates to the designed position under the action of the internal and external pressure difference. The pressurizing device is used for increasing the pressure in the sealed container to simulate the hydrostatic pressure in the deep sea. The first pressure loading mechanism provides downward pressure to the second well under the control of the first pressure control device to simulate the action of the gravity of the well control equipment and the marine riser assembly and the like on the suction pile model in the drilling process. The second pressure loading mechanism provides irregularly changed horizontal thrust to the suction pile model under the control of the second pressure control device to simulate the action of the wind, wave and ocean current and the like on the suction pile model in the drilling process. The displacement detection piece detects the longitudinal displacement of the suction pile model, and the inclination detection piece detects the inclination angle change of the suction pile model. The double-well suction pile simulation bearing test device provided by the application can simulate the state of the suction pile model in the deep water shallow soft stratum under the action of non-uniform load in the drilling process, and provides a basis for the design of the double-well suction pile model.

[0019] Further, in the double-well suction pile simulation bearing test method provided by the application, the method is implemented based on the double-well suction pile simulation bearing test device described above, and therefore has the same advantages as described above. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0021] Figure 1 is a sectional view of a double-well suction pile simulation bearing test device provided by an embodiment of the present application; Figure 2 is an enlarged view of a suction pile model provided by an embodiment of the present application.

[0022] Reference signs: 100: sealed container; 110: box body; 120: box cover; 200: suction pile model; 210: first wellhead; 220: second wellhead; 230: suction port; 240: pile body; 250: first prefabricated guide pipe; 260: second prefabricated guide pipe; 270: first pre-inclined sleeve; 280: second pre-inclined sleeve; 300: soil layer; 400: water; 510: first air pump; 520: suction pipe; 610: second air pump; 620: pressurizing pipe; 630: air pressure sensor; 710: first linear driving device; 720: vertical force transmission rod; 810: second linear driving device; 820: horizontal force transmission rod; 910: displacement sensor; 920: inclination sensor. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.

[0024] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0025] In addition, the terms "first", "second", etc. are used only for the purpose of description and do not imply or imply relative importance or imply the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0026] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be the first feature directly above or obliquely above the second feature, or it can only mean that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be the first feature directly below or obliquely below the second feature, or it can only mean that the first feature is lower than the second feature in horizontal height.

[0028] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0029] The application provides a double-well mouth suction pile simulation bearing test device, which comprises a sealed container, a suction pile model, a negative pressure device, a pressurizing device, a vertical loading assembly, a horizontal loading assembly and a detection assembly. The sealed container is internally provided with a soil layer and water of a preset depth, simulating a deep sea shallow soft stratum and a seawater environment. The suction pile model is placed on the soil layer in the container, and a first well mouth and a second well mouth are symmetrically formed on the top of the suction pile model, and a suction port is arranged. The negative pressure device is connected with the suction port, and provides negative pressure for the inside of the model to help the model to penetrate. The pressurizing device is connected with the sealed container, and the internal pressure is increased to simulate the deep sea hydrostatic pressure. The vertical loading assembly comprises a first pressure loading mechanism and a first pressure control device, and the loading end of the first pressure loading mechanism is connected with the second well mouth to provide a controllable down pressure, simulating the gravity of drilling equipment (such as well control equipment and a riser). The horizontal loading assembly comprises a second pressure loading mechanism and a second pressure control device, and the loading end of the second pressure loading mechanism is connected with the second well mouth to provide a controllable irregularly changed lateral force, simulating the effects of wind, waves and ocean current. The detection assembly comprises a displacement detection piece and an inclination detection piece. The device can simulate the bearing state of the suction pile in the deep sea shallow soft stratum under the gravity of the drilling equipment and the irregular environmental load (wind, waves and current), and detect the displacement and inclination of the suction pile, thereby providing a basis for the design of the double-well mouth suction pile.

[0030] The double-well mouth suction pile simulation bearing test device of the application will be described below. Figure 1 and Figure 2 The double-well mouth suction pile simulation bearing test device of the application will be described below.

[0031] The double-well mouth suction pile simulation bearing test device of the application will be described below.

[0032] The sealed container 100 is internally provided with an accommodating space, which is used for laying the soil layer 300 and the water 400 of the preset depth, and is used for simulating the deep sea shallow soft stratum and the seawater environment.

[0033] The suction pile model 200 is used for simulating the double-well mouth suction pile, and is used for being placed on the soil layer 300. The top of the suction pile model 200 is provided with the first well mouth 210 and the second well mouth 220, and the axis lines of the first well mouth 210 and the second well mouth 220 are symmetrical about the vertical axis line of the suction pile model 200. In addition, the suction pile model 200 is further provided with the suction port 230.

[0034] The negative pressure device can be arranged outside the sealed container 100, and the suction end of the negative pressure device extends into the sealed container 100 and is connected with the suction port 230 on the suction pile model 200. The negative pressure device can suck the air and the water 400 in the suction pile model 200 to the outside, so that the negative pressure is formed in the suction pile model 200, and then the suction pile model 200 penetrates into the soil layer 300 to the preset depth under the action of the internal and external pressure difference.

[0035] The pressurizing device can also be arranged outside the sealed container 100, and the pressurizing device is used to communicate with the inside of the sealed container 100 and to increase the pressure in the sealed container 100 to simulate the deep-sea hydrostatic pressure.

[0036] The vertical loading assembly includes a first pressure loading mechanism and a first pressure control device, the first pressure loading mechanism can be arranged between the inside top of the sealed container 100 and the second wellhead 220, and the first pressure control device is used to control the down pressure provided by the first pressure loading mechanism to the second wellhead 220. The vertical loading assembly is used to provide a controllable down pressure to the second wellhead 220 to simulate the down pressure provided by the well control equipment and the drilling equipment such as the riser to the second wellhead 220.

[0037] The horizontal loading assembly includes a second pressure loading mechanism and a second pressure control device, the second pressure loading mechanism can be arranged on the sidewall of the sealed container 100, and the second pressure loading mechanism can be connected with the first pressure loading mechanism, the second wellhead 220 or the suction pile model 200 directly, and the second pressure control device can control the second pressure loading mechanism to provide an irregularly changed thrust to simulate the effect of wind, wave and ocean current on the suction pile model 200.

[0038] The detection assembly can include a displacement detection member and an inclination detection member, the displacement detection member is used to detect the longitudinal displacement of the suction pile model 200, and the inclination detection member is used to detect the inclination angle of the suction pile model 200.

[0039] During the test, the soil layer 300 and the water 400 laid in the sealed container 100 are used to simulate the deep-sea environment shallow soft stratum and seawater, the suction pile model 200 penetrates into the soil layer 300 to a certain depth by relying on its own gravity, and then the negative pressure device provides negative pressure to the inside of the suction pile model 200, and the suction pile model 200 penetrates to the designed position under the action of the internal and external pressure difference. The pressurizing device is used to increase the pressure in the sealed container 100 to simulate the hydrostatic pressure in the deep sea, the first pressure loading mechanism provides a controllable down pressure to the second wellhead 220 under the control of the first pressure control device to simulate the gravity of the well control equipment and the riser assembly and other drilling equipment on the suction pile model 200, and the second pressure loading mechanism provides an irregularly changed horizontal thrust to the suction pile model 200 under the control of the second pressure control device to simulate the effect of wind, wave and ocean current on the suction pile model 200 during the drilling process. The displacement detection member detects the longitudinal displacement of the suction pile model 200, and the inclination detection member detects the inclination angle change of the suction pile model 200. The double-wellhead suction pile simulation load test device provided by the application can simulate the state of the deep-sea shallow soft stratum when the suction pile model 200 is subjected to non-uniform load during the drilling process, and provides a basis for the design of the double-wellhead suction pile model 200.

[0040] In some embodiments, the sealed container 100 can include a box body 110 and a box cover 120.

[0041] The box body 110 is a pressure-resistant model box body, which is made of high-strength materials such as metal, alloy, polymer material, etc. Further, the box body 110 can be a cuboid.

[0042] The box cover 120 is arranged on the top of the box body 110 and can be opened and closed to open or close the box body 110. When the cover is in an open state, the box body 110 can be operated. When the cover is in a closed state, the box body 110 and the cover are sealingly connected to form a closed space in the box body 110.

[0043] In some embodiments, the suction pile model 200 includes a pile body 240, a prefabricated guide pipe, and a prefabricated inclined sleeve.

[0044] The pile body 240 can be a hollow cylinder structure with an open bottom. The first wellhead 210 and the second wellhead 220 are arranged on the top of the pile body 240, and the axes of the first wellhead 210 and the second wellhead 220 are symmetrically arranged about the axis of the pile body 240. The suction port 230 can be arranged on the top or sidewall of the pile body 240.

[0045] The prefabricated guide pipe includes a first prefabricated guide pipe 250 and a second prefabricated guide pipe 260, and the prefabricated inclined sleeve includes a first prefabricated inclined sleeve 270 and a second prefabricated inclined sleeve 280. The first prefabricated guide pipe 250 is arranged in the first wellhead 210, and the first prefabricated inclined sleeve 270 is arranged in the first prefabricated guide pipe 250. The second prefabricated guide pipe 260 is arranged in the second wellhead 220, and the second prefabricated inclined sleeve 280 is arranged in the second prefabricated guide pipe 260.

[0046] The first prefabricated guide pipe 250 and the second prefabricated guide pipe 260 are the same in size and material, and the first prefabricated inclined sleeve 270 and the second prefabricated inclined sleeve 280 are the same in size and material.

[0047] The first prefabricated guide pipe 250 and the second prefabricated guide pipe 260 are used to provide accurate guidance for the installation of the suction pile model 200, which can ensure that the suction pile model 200 maintains the correct direction and position during installation. The first prefabricated inclined sleeve 270 and the second prefabricated inclined sleeve 280 can provide the required inclination angle for the suction pile model 200 during installation, ensuring that the suction pile is installed according to the design requirements. In addition, the prefabricated inclined sleeve can also increase the stability of the suction pile model 200.

[0048] In some embodiments, the negative pressure device can include a first air pump 510 and a suction pipe 520. The first air pump 510 can be arranged outside the sealed container 100, one end of the suction pipe 520 is connected to the air inlet of the first air pump 510, and the other end of the suction pipe 520 penetrates into the sealed container 100 and is connected to the suction port 230 on the suction pile model 200. When the first air pump 510 is started, the gas and water 400 in the pile body 240 of the suction pile model 200 can be pumped out, so that a negative pressure is formed in the pile body 240, and under the action of the internal and external pressure difference, the pile body 240 penetrates into the designed depth.

[0049] In some embodiments, the pressurizing device includes a second air pump 610 and a pressurizing pipe 620. The second air pump 610 can be arranged outside the sealed container 100, and an air inlet is arranged on the sealed container 100 to communicate between the inside and outside of the sealed container 100. One end of the pressurizing pipe 620 is connected to the air outlet of the second air pump 610, and the other end is connected to the air inlet on the sealed container 100. When the second air pump 610 is started, high-pressure gas can be injected into the sealed container 100 through the pressurizing pipe 620 to increase the pressure in the sealed container 100 to simulate the deep-sea hydrostatic pressure.

[0050] In further embodiments, the detection assembly further includes a gas pressure detection device, which is arranged in the sealed container 100, specifically a gas pressure sensor 630, which can detect the pressure in the sealed container 100 in real time.

[0051] In some embodiments, the first pressure loading mechanism can include a first linear drive device 710 and a vertical force transmission rod 720. The first linear drive device 710 can be arranged inside the tank cover 120 of the sealed container 100 and above the second wellhead 220. The first linear drive device 710 extends downward and retracts upward. The top end of the vertical force transmission rod 720 is connected to the telescopic end of the first linear drive device 710, and the bottom end is in abutment with the second wellhead 220.

[0052] During the test, the first linear drive device 710 can drive the vertical force transmission rod 720 to move downward under the control of the first pressure control device, so as to apply a controllable downward pressure to the second wellhead 220 to simulate the effect of the gravity of the well control equipment and the marine riser assembly on the suction pile model 200.

[0053] The second pressure loading mechanism comprises a second linear driving device 810 and a horizontal force transmission rod 820. The second linear driving device 810 can be arranged on the sidewall of the sealed container 100 and located at the side of the second wellhead 220 away from the first wellhead 210. The horizontal force transmission rod 820 is arranged perpendicularly to the vertical force transmission rod 720. One end of the horizontal force transmission rod 820 is connected to the telescopic end of the second linear telescopic device, and the other end is connected to the vertical force transmission rod 720. The horizontal force transmission rod 820 is rotatably connected to the vertical force transmission rod 720 about the axis of the vertical force transmission rod 720 and slidably connected to the vertical force transmission rod 720 along the axis of the vertical force transmission rod 720.

[0054] During the test, the second linear driving device 810 can drive the horizontal force transmission rod 820 to move in the horizontal direction under the control of the second pressure control device, so as to apply a horizontal thrust with varying size to the vertical force transmission rod 720. The vertical force transmission rod 720 transmits the horizontal thrust to the second wellhead 220, so as to simulate the influence of wind, waves, flow and the like on the suction pile model 200.

[0055] The combination of the first pressure loading mechanism and the second pressure loading mechanism can simulate the real state of the suction pile model 200 subjected to non-uniform load during the drilling operation in the deep water and soft stratum, has the advantages of simple test procedure and high reduction degree, and provides a basis for the design of the double-wellhead suction pile.

[0056] It should be noted that the first linear driving device 710 and the second linear driving device 810 comprise any one of the following: an electric cylinder, an air cylinder, and a hydraulic cylinder.

[0057] In some embodiments, the displacement detection member can be a displacement sensor 910. The displacement sensor 910 can be arranged on the box cover 120 and located above the suction pile model 200, so as to detect the longitudinal displacement 3002 of the suction pile model 200. In some embodiments, the inclination detection member can be an inclination sensor 920. The inclination sensor 920 can be arranged on the sidewall of the pile body 240 of the suction pile model 200. The inclination sensor 920 detects the overturning condition of the suction pile model 200 under the action of the non-uniform load.

[0058] The number of inclination sensors 920 is multiple. The multiple inclination sensors 920 are arranged on the outer sidewall of the pile body 240 in the circumferential direction, so as to detect the overturning condition of the suction pile model 200 under the action of the non-uniform load.

[0059] The double-wellhead suction pile simulation load test method provided by the present application is described below. The double-wellhead suction pile simulation load test method described below can be correspondingly referred to the double-wellhead suction pile simulation load test device described above.

[0060] The embodiment of the present application also provides a double-well mouth suction pile simulation bearing test method, which is realized based on the double-well mouth suction pile simulation bearing test device as described above, and comprises the following steps: In step S100, a preset scale ratio is determined, and the size of the double-well mouth suction pile to be simulated, the weight of the double-well mouth suction pile to be simulated, the depth to be reached by the double-well mouth suction pile to be simulated, the data of the in-situ stratum soil, and the deep sea hydrostatic pressure value of the position where the double-well mouth suction pile to be simulated is located are obtained, wherein the data of the in-situ stratum soil at least includes the shear strength, mineral composition, particle size distribution and stratum particle density of the in-situ stratum soil.

[0061] In step S200, the test soil sample is compounded based on the preset scale ratio and the data of the in-situ stratum soil, and the test soil sample is laid in the sealed container 100.

[0062] In step S300, the size and weight of the suction pile model 200 are determined based on the preset scale ratio and the size and weight of the double-well mouth suction pile to be simulated, the suction pile model 200 is manufactured based on the size and weight of the suction pile model 200, and the suction pile model 200 is placed at the top center of the test soil sample.

[0063] In step S400, the vertical loading assembly and the horizontal loading assembly are drivingly connected with the second well mouth 220 of the suction pile model 200, and the negative pressure device is connected with the suction port 230 of the suction pile model 200.

[0064] In step S500, the water 400 is added in the sealed container 100, and the depth of the water 400 satisfies that the top of the suction pile model 200 is below the water surface when the suction pile model 200 penetrates to 20 centimeters away from the mud line.

[0065] In step S600, the environmental pressure in the sealed container 100 is calculated based on the deep sea hydrostatic pressure value and the preset scale ratio, and the pressurizing device is started to make the pressure in the sealed container 100 reach the environmental pressure.

[0066] In step S700, the test depth to be reached by the suction pile model 200 is calculated based on the depth to be reached by the double-well mouth suction pile to be simulated and the preset scale ratio, the suction pile model 200 is penetrated to a certain depth by relying on the self weight, then the negative pressure device is started to perform suction, and the suction pile model 200 continues to penetrate until the test depth is reached under the action of the internal and external pressure difference.

[0067] In step S800, the non-uniform load is applied to the suction pile model 200 by using the vertical loading assembly and the horizontal loading assembly, and the dynamic response data of the suction pile model 200 under the action of the non-uniform load is detected by using the displacement detection member and the inclination detection member.

[0068] Specifically, first, a preset scale is determined, for example, the preset scale can be 10:1. Then the size and weight of the required simulated double-well suction pile and the depth required to be reached by the required simulated double-well suction pile are calculated.

[0069] At the same time, the data of the in-situ stratum soil and the hydrostatic pressure value of the position where the required simulated double-well suction pile is located, and the data of the in-situ stratum soil of the position where the required simulated double-well suction pile is located are obtained, which at least includes the shear strength, mineral composition, particle size distribution and stratum particle density of the in-situ stratum soil.

[0070] According to the preset scale and the data of the in-situ stratum soil, the test soil sample is configured, the sealed container 100 is opened, and the configured test soil sample is placed in the sealed container 100 to simulate the deep sea soft stratum.

[0071] The size, weight and depth required to be reached of the required simulated double-well suction pile are reduced by the preset scale to obtain the size, weight and test depth value required to be reached of the suction pile model 200. The suction pile model 200 is manufactured according to the obtained size and weight of the suction pile model 200.

[0072] Then the suction pile model 200 is placed at the top center of the test soil sample, and the vertical loading assembly and the horizontal loading assembly are drivingly connected with the second wellhead 220 of the suction pile model 200, specifically the bottom of the vertical force transmission rod 720 of the vertical loading assembly is abutted with the second wellhead 220 of the suction pile model 200. Then the suction pipe 520 of the negative pressure device is connected with the suction port 230 of the suction pile model 200.

[0073] Then water 400 is added into the sealed container 100, and the depth of the water 400 needs to meet that when the suction pile model 200 penetrates to 20 centimeters away from the mud line, the top of the suction pile model 200 is below the water surface.

[0074] The hydrostatic pressure value is reduced by the preset scale to obtain the required environmental pressure of the sealed container 100, and the pressurizing device is opened to increase the pressure in the sealed container 100 to the environmental pressure.

[0075] Then the depth required to be reached by the required simulated double-well suction pile is reduced by the preset scale to obtain the test depth required to be reached by the suction pile model 200. After the suction pile model 200 penetrates to a certain depth by relying on the self-weight, the negative pressure device is opened for suction, and under the action of the internal and external pressure difference, the suction pile model 200 continues to penetrate until the test depth is reached.

[0076] Finally, the vertical loading assembly and the horizontal loading assembly are used to apply non-uniform load to the suction pile model 200, and the displacement detection member and the inclination detection member are used to detect the displacement value and the inclination angle value of the suction pile model 200 under the action of the non-uniform load.

[0077] Since the double-well suction pile simulation bearing test method provided by the embodiments of the present application is implemented based on the double-well suction pile simulation bearing test device described above, the same advantages as described above are achieved.

[0078] In some embodiments, for the step S300 of making the suction pile model 200 based on the weight of the suction pile model 200, the following steps are included: The step S310 of injecting the counterweight material in the suction pile model 200 adjusts the weight of the suction pile model 200.

[0079] Specifically, the cement can be pre-filled in the preset conduit and the pre-inclined sleeve to make the weight of the suction pile model 200 equal to the required weight.

[0080] In some embodiments, for the step S200, the following steps are included: The step S210 of artificially compounding the soil sample based on the mineral composition, the particle size distribution and the formation particle density of the in-situ formation soil; The step S220 of weighing the soil sample based on the thickness of the in-situ formation soil and the preset scaling ratio; The step S230 of determining the test shear strength of the test soil sample based on the shear strength of the in-situ formation soil and the preset scaling ratio, and cyclically performing the following steps until the shear strength of the test soil sample is close to the test shear strength: The step S231 of adding 50% of the saturated water amount and compacting the soil sample; The step S232 of adding 30% of the saturated water amount, wrapping the soil sample with the plastic wrap and keeping still for 8 hours to make the soil sample fully absorb water; The step S233 of adding the remaining 20% of the saturated water amount, wrapping the soil sample with the plastic wrap and keeping still for 8 hours to make the soil sample fully absorb water.

[0081] Specifically, according to the mineral composition, the particle size distribution and the formation particle density of the in-situ formation soil, the soil particles are artificially compounded, and each layer of the soil sample is made according to the following method. The lower layer of the soil sample is first made, and the soil sample is compacted from bottom to top.

[0082] First, the thickness of the soil layer is determined, and the thickness of the test soil layer is obtained by scaling the thickness by a preset scaling ratio, and the soil sample is weighed based on the thickness.

[0083] 50% of the saturated water amount is added to the weighed soil sample, and the soil sample is compacted by using N5 pressure. Then, 30% of the saturated water amount is added, the soil sample is wrapped with the plastic wrap and kept still for 8 hours to make the soil sample fully absorb water. Then, the remaining 20% of the saturated water amount is added, the soil sample is wrapped with the plastic wrap and kept still for 8 hours to make the soil sample fully absorb water.

[0084] The test shear strength of the test soil sample is obtained by reducing the shear strength of the in-situ stratum soil by a predetermined reduction ratio. Then, the shear strength of the artificially compacted test soil sample is measured, for example, using a portable cross shear plate. If the measured shear strength is greater than the test shear strength, the pressure N5 is reduced to N4, and steps S231 to S233 are repeated until the shear strength of the test soil sample is close to the test shear strength. If the measured shear strength is less than the shear strength of the in-situ stratum soil, the pressure N5 is increased to N6, and steps S231 to S233 are repeatedly executed until the shear strength of the test soil sample is close to the test shear strength.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the same. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some or all of the technical features therein. Such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should be covered in the scope of the claims and the specification of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A simulated bearing capacity test device for dual-wellhead suction piles, characterized in that, include: A sealed container (100) is used to lay a soil layer (300), water (400) of a preset depth, and a suction pile model (200). The suction pile model (200) is used to place on the soil layer (300). The suction pile model (200) has a first well opening (210), a second well opening (220), and a suction port (230). The first well opening (210) and the second well opening (220) are symmetrically arranged on the top of the suction pile model (200) about the vertical axis of the suction pile model (200). A negative pressure device is connected to the suction port (230) and is used to provide negative pressure within the suction pile model (200); A pressurizing device for connection to the sealed container (100) and for increasing the pressure inside the sealed container (100); A vertical loading assembly, comprising a first pressure loading mechanism and a first pressure control device, wherein the pressure loading end of the first pressure loading mechanism is connected to the second wellhead (220) in a transmission manner, and the first pressure control device is used to control the first pressure loading mechanism to provide vertical downward pressure to the suction pile model (200); A horizontal loading component, comprising a second pressure loading mechanism and a second pressure control device, wherein the pressure loading end of the second pressure loading mechanism is connected to the second wellhead (220) via transmission, and the second pressure control device is used to control the second pressure loading mechanism to provide a horizontal lateral force to the suction pile model (200), and the lateral force changes irregularly; The detection component includes a displacement detector and an inclination detector. The displacement detector is used to detect the longitudinal displacement of the suction pile model (200), and the inclination detector is used to detect the inclination angle of the suction pile model (200).

2. The dual-wellhead suction pile simulated bearing test device according to claim 1, characterized in that, The sealed container (100) includes a box body (110) and a box cover (120). The box cover (120) is openable and closable with the box body (110), and when the box cover (120) is closed, the box cover (120) is sealed to the box body (110).

3. The dual-wellhead suction pile simulated bearing test device according to claim 1, characterized in that, The suction pile model (200) includes: The pile body (240) is hollow inside and open at the bottom. The first wellhead (210) and the second wellhead (220) are located on the top of the pile body (240), and the axes of the first wellhead (210) and the second wellhead (220) are symmetrical about the axis of the pile body (240). The suction port (230) is located on the pile body (240). The prefabricated conduit is provided in both the first wellhead (210) and the second wellhead (220); Pre-angled sleeves are provided inside all the prefabricated conduits.

4. The dual-wellhead suction pile simulated bearing test device according to claim 1, characterized in that, The negative pressure device includes a first air pump (510) and a suction pipe (520). The first air pump (510) is located outside the sealed container (100). One end of the suction pipe (520) is connected to the air inlet of the first air pump (510), and the other end of the suction pipe (520) is connected to the suction port (230) of the suction pile model (200).

5. The dual-wellhead suction pile simulated bearing test device according to claim 1, characterized in that, The pressurizing device includes a second air pump (610) and a pressurizing pipe (620). The second air pump (610) is located outside the sealed container (100). One end of the pressurizing pipe (620) is connected to the air outlet of the second air pump (610), and the other end of the pressurizing pipe (620) is connected to the sealed container (100).

6. The dual-wellhead suction pile simulated bearing test device according to claim 1, characterized in that, The first pressure loading mechanism includes a first linear drive device (710) and a vertical force transmission rod (720). The first linear drive device (710) is connected to the sealed container (100) and is located above the second wellhead (220). The vertical force transmission rod (720) is disposed between the first linear drive device (710) and the second wellhead (220). The first linear drive device (710) is used to drive the vertical force transmission rod (720) to move in the vertical direction. The second pressure loading mechanism includes a second linear drive device (810) and a horizontal force transmission rod. The second linear drive device (810) is connected to the sealed container (100) and is located on one side of the vertical force transmission rod (720). One end of the horizontal force transmission rod is connected to the second linear drive device (810), and the other end is slidably and rotatably connected to the vertical force transmission rod (720). The rotation axis and the sliding axis are both collinear with the axis of the vertical force transmission rod (720).

7. The dual-inlet suction pile simulated bearing test device according to claim 5, characterized in that, The detection assembly also includes a pressure detection element.

8. A method for simulating the bearing capacity of a double-wellhead suction pile, characterized in that, Based on the dual-wellhead suction pile simulated bearing test device as described in any one of claims 1 to 7, the method includes: Determine the preset scale and obtain the dimensions of the dual-wellhead suction pile to be simulated, the weight of the dual-wellhead suction pile to be simulated, the depth to be reached by the dual-wellhead suction pile to be simulated, the data of the in-situ stratum soil, and the hydrostatic pressure value at the location of the dual-wellhead suction pile to be simulated. The data of the in-situ stratum soil shall include at least the shear strength, mineral composition, particle size distribution and stratum particle density of the in-situ stratum soil. A soil layer is prepared based on the preset scale and the data of the in-situ stratum soil, and the soil layer is laid in a sealed container (100); Based on the preset scale and the size and weight of the required simulated double wellhead suction pile, determine the size and weight of the suction pile model (200), make the suction pile model (200) based on the size and weight of the suction pile model (200), and place the suction pile model (200) at the top center of the test soil sample; The vertical loading component and the horizontal loading component are connected to the second wellhead (220) of the suction pile model (200) and the negative pressure device is connected to the suction port (230) of the suction pile model (200); Water (400) is added into the sealed container (100), and the depth of the water (400) is such that when the suction pile model (200) penetrates to a distance of 20 cm from the mud line, the top of the suction pile model (200) is below the water surface; Based on the hydrostatic pressure value and the preset scaling ratio, calculate the required environmental pressure inside the sealed container (100), and turn on the pressurization device to make the pressure inside the sealed container (100) reach the environmental pressure. Based on the required depth of the dual-wellhead suction pile to be simulated and the preset scaling ratio, the required test depth of the suction pile model (200) is calculated. After the suction pile model (200) penetrates to a certain depth by its own weight, the negative pressure device is turned on for suction. Under the action of the internal and external pressure difference, the suction pile model (200) continues to penetrate until it reaches the test depth. Non-uniform loads are applied to the suction pile model (200) using the vertical loading component and the horizontal loading component, and the dynamic response data of the suction pile model (200) under non-uniform loads are detected using displacement detection components and tilt detection components.

9. The method for simulating the bearing capacity of a double-wellhead suction pile according to claim 8, characterized in that, The suction pile model (200) is made based on the weight of the suction pile model (200), including injecting counterweight material into the suction pile model (200) to adjust the weight of the suction pile model (200).

10. The method for simulating the bearing capacity of a dual-wellhead suction pile according to claim 8, characterized in that, Based on the preset scale and the data of the in-situ soil, a soil layer is prepared within the suction pile model (200), including: Based on the mineral composition, particle size distribution, and particle density of the in-situ strata soil, artificially compounded test soil samples were prepared. Based on the thickness of the in-situ soil strata and the preset reduction ratio, the test soil sample is weighed. Based on the shear strength of the in-situ soil and the preset reduction ratio, the test shear strength of the soil layer is determined, and the following steps are repeated until the shear strength of the soil layer is close to the test shear strength: Add 50% saturated water and press the test soil sample; Add 30% saturated water, wrap with plastic wrap and let stand for 8 hours to allow the test soil sample to fully absorb water (400). Add the remaining 20% ​​of saturated water, wrap with plastic wrap and let stand for 8 hours to allow the test soil sample to fully absorb water (400).

Images