CN111829890A - Testing system and testing method for horizontal loading of riser composite pipe column - Google Patents

Abstract

The invention provides a horizontal loading test system and a horizontal loading test method for a riser composite pipe column, wherein the test system comprises: the horizontal loading device is used for horizontally and statically loading the pile head of the riser composite pipe column; the displacement sensor is arranged at the pile head of the riser pipe composite pipe column along the horizontal loading direction and is used for measuring the offset of the pile head of the riser pipe composite pipe column; the first strain sensors are arranged along the longitudinal direction, and are respectively arranged on two opposite sides of at least one position of the drilling riser pipe at the same height in the longitudinal direction; and the second strain sensors are arranged along the longitudinal direction, and the second strain sensors are respectively arranged on two opposite sides of at least one longitudinal position of the surface sleeve at the same height. The method is beneficial to improving the accuracy of the ultimate bearing capacity value of the riser composite pipe column obtained by testing.

Description

Testing system and testing method for horizontal loading of riser composite pipe column

Technical Field

The invention relates to the technical field of marine drilling equipment, in particular to a horizontal loading test system and a horizontal loading test method for a riser composite pipe column.

Background

The drilling riser pipe is key equipment for connecting wellhead equipment and seabed oil and gas reservoirs in ocean oil and gas drilling operation, not only provides a circulating channel for drilling fluid, but also provides bearing capacity for the wellhead equipment, and ensures that the wellhead equipment is stabilized at a preset position.

The load bearing capacity of the drilling riser is mainly provided by the lateral friction between the drilling riser and the soil. And in the well completion stage, cement slurry is injected into an annular space formed between the drilling riser and the surface casing pipe, and the drilling riser composite pipe column structure of the drilling riser-cement sheath-surface casing pipe is formed after the cement slurry is solidified. The formation of the drilling riser pipe composite pipe column consolidates the drilling riser pipe and the surface casing pipe into a whole, and increases the lateral friction force between the whole pipe column and the soil, thereby further improving the bearing capacity and stability of the drilling riser pipe.

When the composite pipe column structure of the drilling riser pipe is used for bearing wellhead equipment, the mud penetration depth of the drilling riser pipe needs to be designed according to the limit bearing capacity data. On one hand, when the measured value of the ultimate bearing capacity of the composite pipe column structure of the drilling riser is too small relative to the actual value, the bearing capacity is insufficient, and safety accidents such as well mouth sinking instability and the like are caused; on the other hand, when the measured value of the ultimate bearing capacity of the composite pipe column structure of the drilling riser pipe is too large relative to the actual value, economic waste is brought, and safety accidents such as hammer rejection and the like of the drilling riser pipe are caused, so that the safety of drilling operation is threatened. However, a device for carrying out pressure-bearing simulation test on the composite pipe column structure of the drilling riser pipe is absent at present, so that an accurate limit bearing capacity value is difficult to obtain, difficulty is brought to structural design of a drilling well body, and difficulty in guaranteeing safety of the drilling riser pipe and a well head is increased.

Disclosure of Invention

The invention aims to provide a system and a method for testing horizontal loading of a riser composite pipe column, so as to improve the accuracy of a limit bearing force value of the riser composite pipe column obtained by testing.

The above object of the present invention can be achieved by the following technical solutions:

the invention provides a horizontal loading test system of a riser pipe composite pipe column, which is used for carrying out horizontal loading test on the riser pipe composite pipe column, wherein the riser pipe composite pipe column comprises a drilling riser pipe, a surface casing pipe arranged in the drilling riser pipe and an annular cement ring arranged between the drilling riser pipe and the surface casing pipe; the test system comprises:

the horizontal loading device is used for horizontally and statically loading the pile head of the riser composite pipe column;

the displacement sensor is arranged at the pile head of the riser pipe composite pipe column along the horizontal loading direction and is used for measuring the offset of the pile head of the riser pipe composite pipe column;

the first strain sensors are arranged along the longitudinal direction, and are respectively arranged on two opposite sides of at least one position of the drilling riser pipe at the same height in the longitudinal direction;

and the second strain sensors are arranged along the longitudinal direction, and the second strain sensors are respectively arranged on two opposite sides of at least one longitudinal position of the surface sleeve at the same height.

In a preferred embodiment, the test system comprises a displacement reference beam which is fixedly arranged, the displacement reference beam is perpendicular to the horizontal loading direction, the displacement sensor is provided with a fixed end and a measuring end, and the fixed end and the measuring end are respectively connected with a pile head of the riser composite pipe column and the displacement reference beam in a one-to-one correspondence manner.

In a preferred embodiment, the displacement reference beam is provided with a flow channel for liquid flow, the flow channel being provided with a water outlet and a water inlet.

In a preferred embodiment, the outer wall of the drilling riser is provided with a strain sensor protection structure, and the strain sensor protection structure comprises a protection groove and a fixed protection layer fixedly connected in the protection groove; on the drilling riser pipe, the protection groove is fixed in the outer wall of the drilling riser pipe, the first strain sensor is arranged in the protection groove, and the fixed protection layer wraps the first strain sensor.

In a preferred embodiment, the fixed protective layer is of a multilayer structure and comprises a fixed layer, an inner protective layer and an outer protective layer, the fixed layer is arranged between the outer wall of the drilling riser and the first strain sensor, the inner protective layer and the outer protective layer are sequentially distributed from inside to outside, and the outer protective layer is made of epoxy resin.

In a preferred embodiment, the outer wall of the surface casing is provided with a strain sensor protection structure, and the strain sensor protection structure comprises a protection groove and a fixed protection layer fixedly connected in the protection groove; on the surface casing pipe, the protection groove is fixed in the outer wall of surface casing pipe, the second strain sensor is located in the protection groove, fixed protective layer parcel the second strain sensor.

In a preferred embodiment, the fixed protective layer is of a multilayer structure and comprises a fixed layer, an inner protective layer and an outer protective layer, the fixed layer is arranged between the outer wall of the surface casing and the second strain sensor, the inner protective layer and the outer protective layer are sequentially distributed from inside to outside, and the outer protective layer is made of epoxy resin.

In a preferred embodiment, the strain sensor protection structure includes a plurality of partition plates disposed in the protection groove, the partition plates are fixedly connected to an inner wall of the protection groove, and the plurality of partition plates are distributed at intervals along the longitudinal direction.

In a preferred embodiment, the horizontal loading device includes a reaction beam, an anchor pile and a hydraulic jack, the anchor pile is fixedly arranged on one side of the riser composite pipe string, the reaction beam is connected with the anchor pile, the anchor pile can prevent the reaction beam from moving along the direction of the horizontal loading direction, and the hydraulic jack is arranged between the riser composite pipe string and the reaction beam along the horizontal loading direction and can extend and retract to abut against the riser composite pipe string and the reaction beam respectively.

In a preferred embodiment, the horizontal loading device comprises a gravity block and a hydraulic jack, the gravity block is arranged on one side of the riser pipe composite pipe column, the hydraulic jack is arranged between the riser pipe composite pipe column and the gravity block along the horizontal loading direction and can stretch out and draw back to abut against the riser pipe composite pipe column and the gravity block respectively, and the gravity block can prevent the hydraulic jack from moving reversely along the horizontal loading direction by means of friction force.

The invention provides a horizontal loading test method for a riser composite pipe column, which comprises the following steps:

step S10, installing a riser pipe composite pipe column, wherein the riser pipe composite pipe column comprises a drilling riser pipe, a surface casing pipe arranged in the drilling riser pipe and an annular cement sheath arranged between the drilling riser pipe and the surface casing pipe;

step S20, arranging first strain sensors on two opposite sides of the outer wall of the drilling riser pipe at the same height in the longitudinal direction respectively along the longitudinal direction; second strain sensors are respectively arranged on two opposite sides of the outer wall of the surface layer sleeve at the same height in the longitudinal direction along the longitudinal direction;

step S30, arranging a horizontal loading device for horizontally and statically loading the pile head of the riser composite pipe column along the horizontal loading direction;

step S40, arranging a displacement sensor for measuring the offset of the pile head of the riser pipe composite pipe column at the pile head of the riser pipe composite pipe column, wherein the displacement sensor is arranged along the horizontal loading direction;

and step S50, the horizontal loading device applies horizontal static force loading to the pile head of the riser composite pipe column, and the pressure of the horizontal static force, the offset of the displacement sensor, the strain of the first strain sensor and the strain of the second strain sensor are collected.

In a preferred embodiment, the step S40 includes: a displacement reference beam is fixedly arranged and is vertical to the horizontal loading direction, and the fixed end and the measuring end of the displacement sensor are respectively connected with the pile head of the riser composite pipe column and the displacement reference beam; the displacement reference beam is provided with a circulation groove for liquid to flow, and the circulation groove is provided with a water outlet and a water inlet.

In a preferred embodiment, the horizontal loading device includes a reaction beam, an anchor pile and a hydraulic jack, the anchor pile is fixedly arranged on one side of the riser composite pipe string, the reaction beam is connected with the anchor pile, the anchor pile can prevent the reaction beam from moving along the direction of the horizontal loading direction, and the hydraulic jack is arranged between the riser composite pipe string and the reaction beam along the horizontal loading direction and can extend and retract to abut against the riser composite pipe string and the reaction beam respectively.

In a preferred embodiment, in the step S50, the horizontal static loading is applied in a stepwise increasing manner; the step S50 includes: step S51, setting the judgment condition of the limit bearing capacity of the pile head; and step S52, increasing the pressure of the applied horizontal static force loading step by step, stopping increasing the horizontal static force loading when the pile head limit bearing capacity judgment condition is reached, and acquiring the pressure of the horizontal static force, the offset of the displacement sensor, the strain of the first strain sensor and the strain of the second strain sensor.

The invention has the characteristics and advantages that:

the horizontal loading test system for the riser pipe composite pipe column provided by the invention is adopted to carry out pressure bearing simulation test, apply horizontal static force to the pile head of the riser pipe composite pipe column, collect the ballast size of the applied horizontal static force, at the same height, two first strain sensors which are oppositely arranged respectively detect longitudinal strain quantities, and the bending deformation quantity of the drilling riser pipe can be obtained through the difference value of the two strain quantities; and at the same height, two second strain sensors which are oppositely arranged detect the longitudinal strain quantity respectively, and the bending deformation quantity of the surface casing can be obtained through the difference value of the two strain quantities. And the displacement sensor measures the offset of the pile head of the riser composite pipe column. The offset of pile head can be known, well drilling riser pipe is along fore-and-aft strain, surface casing is along fore-and-aft strain, and well drilling riser pipe's bending deformation volume and surface casing's bending deformation volume, and the loaded relation between the size of horizontal static force, thereby judge the loaded limit bearing capacity value of horizontal static force that the compound tubular column of riser pipe can bear, the degree of accuracy of the limit bearing capacity value that the test was acquireed has been improved, according to this limit bearing capacity value, be favorable to providing economy for well drilling shaft structural design, scientific and reasonable well drilling riser pipe compound tubular column income mud degree of depth, guarantee well drilling riser pipe and well head's stable safety.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a riser pipe composite string in a horizontal loading test system of the riser pipe composite string provided by the present invention;

FIG. 2a is a top view of a horizontal loading test system for a riser composite tubular column according to the present invention, wherein the horizontal loading test system employs a counter-force anchor pile;

FIG. 2b is a side view of the horizontal loading test system for the riser composite tubular column according to the present invention with a counter-force anchor pile;

fig. 3a is a schematic installation diagram of a first strain sensor, a second strain sensor and a displacement sensor in a horizontal loading test system of a riser composite pipe column provided by the invention;

fig. 3b is a schematic distribution diagram of a first strain sensor, a second strain sensor and a displacement sensor in the horizontal loading test system of the riser composite pipe column provided by the invention;

FIG. 4 is a schematic diagram of a strain sensor protection structure in a horizontal loading test system for a riser composite string provided by the present invention;

FIG. 5 is an enlarged view of a portion of FIG. 4;

FIG. 6 is a schematic view of a horizontal loading test method for a riser composite string according to the present invention;

FIG. 7 is a schematic view of a horizontal loading test system for a riser composite pipe column according to the present invention, wherein the horizontal loading test system is loaded by a gravity block;

FIG. 8 is a partial schematic view of a drilling riser in a horizontal loading test system of a riser composite string provided in the present invention;

fig. 9 is a schematic structural view of a displacement reference beam in the horizontal loading test system for the riser composite pipe column provided by the invention.

The reference numbers illustrate:

10. a riser composite pipe string; 101. longitudinal direction; 102. a horizontal loading direction;

11. a drilling riser pipe; 12. a surface casing; 13. an annular cement sheath; 14. cementing a cement sheath; 15. a wellhead connector;

20. a displacement sensor; 21. a displacement reference beam; 211. a circulation tank; 212. a water outlet; 213. a water inlet; 214. a cover plate; 22. a raised structure;

31. a first strain sensor; 32. a second strain sensor;

40. a strain sensor protection structure; 41. a protective groove; 411. flat steel; 412. a partition plate; 42. fixing the protective layer; 421. a fixed layer; 422. an inner protective layer; 423. an outer protective layer;

50. a horizontal loading device; 501. a controller; 502. a data acquisition unit;

51. a counter-force beam; 52. anchoring piles in counter-force; 53. a hydraulic jack;

61. a gravity block; 62. and (7) stacking and loading platforms.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

The invention provides a horizontal loading test system of a riser composite pipe column, as shown in fig. 1, fig. 2a, fig. 2b and fig. 6, the test system comprises: the composite pipe column of the riser comprises a drilling riser, a surface casing pipe arranged in the drilling riser and an annular cement ring arranged between the drilling riser and the surface casing pipe; the horizontal loading device is used for horizontally and statically loading the pile head of the riser composite pipe column; the displacement sensor is arranged at the pile head of the riser composite pipe column along the horizontal loading direction and is used for measuring the offset of the pile head of the riser composite pipe column; the first strain sensors are arranged along the longitudinal direction, and are respectively arranged on two opposite sides of at least one position of the drilling riser at the same height in the longitudinal direction; the second strain sensors are arranged along the longitudinal direction, and the second strain sensors are respectively arranged on two opposite sides of at least one longitudinal position of the surface layer sleeve at the same height.

The testing system for horizontal loading of the riser composite pipe column is adopted for simulation testing, horizontal static force is applied to the pile head of the riser composite pipe column 10, the magnitude of applied horizontal static force ballast is collected, two first strain sensors 31 which are oppositely arranged at the same height respectively detect longitudinal strain quantities, and the bending deformation quantity of the drilling riser 11 can be obtained through the difference value of the two strain quantities; two second strain sensors 32 oppositely arranged at the same height respectively detect the longitudinal strain amount, and the bending deformation amount of the surface casing 12 can be obtained through the difference value of the two strain amounts. The displacement sensor 20 measures the offset of the pile head of the riser composite string 10. The offset of pile head can be known, well drilling riser pipe 11 is along fore-and-aft strain, the surface casing is along fore-and-aft strain, and well drilling riser pipe 11's bending deformation and surface casing 12's bending deformation, and the relation between the size of the quiet power loading of level, thereby judge the loaded limit bearing capacity value of the quiet power of level that riser pipe composite string 10 can bear, the degree of accuracy of the limit bearing capacity value that the test was obtained has been improved, according to this limit bearing capacity value, be favorable to providing economy for well drilling shaft structural design, scientific and reasonable riser pipe composite string 10 income mud degree of depth, guarantee well drilling riser pipe 11 and the stable safety of well head.

For the convenience of understanding, the horizontal loading test system of the riser composite string is described in four parts below.

Test method

The horizontal loading test system of the riser composite pipe column provided by the invention can work according to the test method shown in FIG. 6, and the test method comprises the following steps: step S10, installing a riser pipe composite pipe column 10, wherein the riser pipe composite pipe column 10 comprises a drilling riser pipe 11, a surface casing pipe 12 arranged in the drilling riser pipe 11 and an annular cement sheath 13 arranged between the drilling riser pipe 11 and the surface casing pipe 12; step S20, arranging first strain sensors 31 along the longitudinal direction 101 on two opposite sides of the outer wall of the drilling riser pipe 11 at the same height in the longitudinal direction; second strain sensors 32 are respectively arranged on two opposite sides of the outer wall of the surface casing 12 at the same height in the longitudinal direction along the longitudinal direction 101; step S30, arranging a horizontal loading device 50 for horizontally and statically loading the pile head of the riser composite pipe column 10 along the horizontal loading direction; step S40, arranging a displacement sensor 20 for measuring the offset of the pile head of the riser pipe composite pipe column 10 at the pile head of the riser pipe composite pipe column 10, wherein the displacement sensor 20 is arranged along the horizontal loading direction 102; step S50, horizontal static force loading is applied, and the magnitude of the pressure of the horizontal static force, the offset of the displacement sensor 20, the magnitude of the strain of the first strain sensor 31, and the magnitude of the strain of the second strain sensor 32 are collected.

Composite pipe column of riser pipe

Designing a limit bearing capacity test model of the composite pipe pile of the drilling riser pipe 11 based on the structural characteristics of the offshore drilling well body; and (4) combining the offshore drilling operation flow to finish the pile forming step.

The test system takes a riser composite pipe column 10 as a main research object. The pile-forming step of the riser composite pipe column 10 comprises the following steps: a piling step, namely hammering the drilling riser pipe 11 into the ground by using a diesel pile hammer or a hydraulic pile hammer; drilling a borehole by using a drill bit in the drilling riser pipe 11, and continuously lowering the surface casing 12 to the bottom of the borehole; and a well cementation step, namely injecting prefabricated cement slurry into an annular space between the drilling riser pipe 11 and the surface casing pipe 12 and an annular space between the surface casing pipe 12 and the soil by using well cementation equipment. The cement returns from bottom to top, a well cementation cement sheath 14 is formed between the surface casing 12 and the soil, and an empty cement sheath 13 is formed between the surface casing 12 and the drilling riser 11.

Preferably, as shown in fig. 1, the riser composite string 10 further comprises a wellhead connector 15, and the wellhead connector 15 is arranged on the top of the surface casing 12. When the pile is formed, after the cement slurry is solidified into a cement sheath, the drilling riser pipe 11 and the surface casing pipe 12 are welded by using the wellhead connector 15, and the pile is formed.

Measuring device

The measuring device is mainly used for measuring and collecting pile head offset and strain, and comprises a displacement sensor 20, a first strain sensor 31 and a second strain sensor 32. In the above test method, step S20 may be performed before running riser string 10 into the ground in step S10.

Firstly, the measurement and collection of pile head offset are introduced.The displacement sensor 20 is arranged at the pile head of the riser composite pipe string 10, and the displacement sensor 20 is arranged along the horizontal loading direction 102 and is used for measuring the pile head offset of the riser composite pipe string 10 under the horizontal load.

Further, the test system comprises a displacement reference beam 21 which is fixedly arranged, the displacement sensor 20 comprises a fixed end and a measuring end, the fixed end and the measuring end of the displacement sensor 20 are respectively connected with the displacement reference beam 21 and the pile head of the riser composite pipe column 10, and the displacement reference beam 21 provides a measurement origin for the displacement sensor 20. As shown in fig. 2a, the displacement sensor 20 may be mounted on a displacement reference beam 21, so that the measuring end of the displacement sensor 20 is connected to the pile head of the riser composite pipe column 10, and the displacement reference beam 21 is used as a measuring reference, which is beneficial to providing a more stable measuring origin for the displacement sensor 20, improving the accuracy of measuring the offset of the pile head, and the displacement sensor 20 measures the offset of the pile head relative to the displacement reference beam 21 and feeds the offset back to the controller. Specifically, the displacement reference beam 21 may be an i-steel beam or a channel steel beam. Specifically, as shown in fig. 2a, the pile head of the riser composite string 10 is provided with a raised structure 22 for abutting against the displacement sensor 20 so as to keep the displacement sensor 20 horizontally disposed.

In an embodiment of the present invention, the displacement reference beam 21 is provided with a circulation groove 211 for flowing liquid, the circulation groove 211 is provided with a water outlet 212 and a water inlet 213, and the liquid in the circulation groove 211 is circulated by a water pump to ensure constant water temperature, so as to reduce thermal expansion and cold contraction of the displacement reference beam 21 and ensure the accuracy and stability of the measurement reference. The displacement reference beam 21 may be a channel steel beam, and a channel on the channel steel beam is used as the circulation channel 211, specifically, as shown in fig. 9, the channel steel beam has a rectangular cross section, and an opening is formed at one side, a cover plate 214 is hermetically connected at the opening, two ends of the channel steel beam are sealed, and the middle of the channel steel beam stores water to form the circulation channel 211 for liquid flowing. As another embodiment, the displacement reference beam 21 may also be a square tube, and a square hole of the square tube may be used as the flow channel 211.

The displacement sensor 20 comprises a fixed end, a measuring end and a display screen, wherein the fixed end can adsorb and fix the displacement sensor 20 on the displacement reference beam 21 by using a magnet; the measuring end is of a telescopic measuring rod body structure, contacts with a protruding structure 22 on the pile head of the riser composite pipe column 10, and is zeroed to serve as a measuring starting point; the display screen can display the displacement sensor readings in real time. The displacement sensor 20 can accurately transmit the displacement signal of the pile head relative to the displacement reference beam 21 to the controller 501 in real time by means of wireless transmission.

The displacement sensor 20 may be a photoelectric sensor that measures the displacement of the head of the riser string 10 in the longitudinal direction 101 to characterize the amount of displacement of the head of the riser string 10 in the longitudinal direction 101. The displacement sensor 20 can be a dial indicator, the dial indicator has a telescopic measuring rod body, the measuring rod body is used as a measuring end and is arranged between the pile head of the riser composite pipe column 10 and the displacement reference beam 21, the measuring rod body is arranged along the longitudinal direction 101, when the measuring rod body is compressed, the degree of the dial indicator is driven to change, so that the offset of the pile head of the riser composite pipe column 10 along the longitudinal direction 101 is represented, and the advantage of high measuring sensitivity is achieved.

The head of the riser composite string 10 may be provided with a plurality of displacement sensors 20, and the measurement points of the plurality of displacement sensors 20 may be symmetrically arranged with respect to a plane passing through the axis of the drilling riser 11. In a specific embodiment, as shown in fig. 2a, the displacement sensor system includes 2 displacement sensors, 2 displacement sensors 20 are fixed on the same horizontal plane, and the measurement points of the 2 displacement sensors 20 are located on the same diameter of a cross section of the drilling riser 11, the horizontal loading direction 102 is perpendicular to a connection line of the two measurement points, the pile head displacement is measured by taking an average value of readings of the 2 displacement sensors 20, and the arrangement scheme of the plurality of displacement sensors 20 can not only improve the measurement accuracy of the pile head displacement, but also compare readings of the displacement sensors 20 in different directions to determine the pile head displacement direction and the displacement angle.

The field operation step of measuring pile head offset during horizontal loading may include the steps of: (1) fixedly placing an I-shaped steel beam on the periphery of the pile perpendicular to the horizontal loading direction 102 to serve as a displacement reference beam 21 of pile head offset; (2) two ends of the displacement reference beam 21 are blocked, a water inlet 213 and a water outlet 212 are arranged, constant-temperature water is circulated, and expansion caused by heat and contraction caused by cold of the displacement reference beam 21 are avoided; (3) selecting a plane near the pile head, and determining 2 arrangement points of the displacement sensor 20 at symmetrical positions along two sides of the periphery of the pile, wherein the 2 arrangement points are positioned in the same horizontal plane, and the connecting line is vertical to the horizontal loading direction 102; (4) fixing the 2 displacement sensors 20 at preset arrangement points by utilizing magnet adsorption, and enabling the telescopic rods at the measuring ends of the displacement sensors to be kept horizontal and to be in contact with the displacement reference beam 21; (5) installing a wireless signal transmitting device around the pile head of the riser composite pipe column 10, so that a monitoring terminal can acquire data of the displacement sensor 20 in real time; (6) the test was started with the displacement sensor 20 set to zero as the monitoring zero.

The measurement and acquisition of strain is described next.As shown in fig. 3a and 3b, on two opposite sides of at least one longitudinal direction 101 of the drilling riser 11 at the same height, a first strain sensor 31 is respectively arranged along the longitudinal direction 101; on opposite sides of the surface casing 12 at least at one point in the longitudinal direction 101 at the same level, a second strain sensor 32 is arranged in the longitudinal direction, respectively. The axis of the drilling riser pipe 11 is parallel to the axis of the surface casing 12, preferably they coincide; the axial direction of the drilling riser pipe 11 is defined as a longitudinal direction 101. Two first strain sensors 31 oppositely arranged at the same height respectively detect longitudinal strain, and the bending deformation of the drilling riser pipe 11 can be obtained through the difference value of the two strain sensors; two second strain sensors 32 oppositely arranged at the same height respectively detect the longitudinal strain amount, and the bending deformation amount of the surface casing 12 can be obtained through the difference value of the two strain amounts. Further, as shown in fig. 3b, at a plurality of height positions in the longitudinal direction 101 of the drilling riser 11, first strain sensors 31 are respectively arranged, and at each height position, the first strain sensors 31 are respectively arranged at two opposite sides; multiple elevations in the longitudinal direction 101 of the surface casing 12The second strain sensors 32 are provided at the respective height positions, and the second strain sensors 32 are provided at the respective opposite sides at each height position.

The first strain sensor 31 may be a fiber optic strain sensor, and during the loading step, the first strain sensor 31 continuously measures the strain signal on the surface of the drilling riser 11 and stores the strain signal in the data collector 502 through the controller. The second strain sensor 32 may be an optical fiber strain sensor, and during the loading step, the first strain sensor 31 continuously measures the surface strain signal of the surface casing 12 and stores the strain signal in the data collector 502 through the controller.

The first strain sensors 31 may be equally spaced along the longitudinal direction 101 and the second strain sensors 32 may be equally spaced along the longitudinal direction 101. According to soil property data of a test site, the composite pipe column structure used in the test of the soil property layering condition of the test site is combined, the arrangement points of the first strain sensor 31 and the second strain sensor 32 are flexibly arranged by adopting a scheme of 'uniform whole and local encryption', and the arrangement points of the first strain sensor 31 and the second strain sensor 32 are arranged in an encrypted manner at the diameter-changing position and the pile end position of the composite pipe column 10 with complex soil body layering, large mechanical property change and water-resisting guide pipe, so that scientific, comprehensive and detailed test data are ensured. Preferably, in the overlapping portion of the drilling riser 11 and the surface casing 12 along the longitudinal direction 101, the longitudinal position of the first strain sensor 31 and the longitudinal position of the second strain sensor 32 correspond to each other, that is, in a cross section at a height in the longitudinal direction 101, the drilling riser 11 is provided with the first strain sensor 31, and the surface casing 12 is provided with the second strain sensor 32, so that the distribution of strain at different positions inside and outside on a cross section can be known by comparing the difference of the bending deformation amount of the drilling riser 11 and the surface casing 12 at the same height.

In order to reduce the damage of the first strain sensor 31 during the pile forming step and during operation, the outer wall of the drilling riser pipe 11 is provided with a strain sensor protection structure 40, and in order to protect the second strain sensor 32, the outer wall of the surface casing 12 is provided with a strain sensor protection structure 40. As shown in fig. 4 and 5, the strain sensor protection structure 40 includes a protection groove 41 and a fixing protection layer 42 fixed in the protection groove 41; on the drilling riser pipe 11, a protection groove 41 is fixed on the outer wall of the drilling riser pipe 11, the first strain sensor 31 is arranged in the protection groove 41, and a fixed protection layer 42 wraps the first strain sensor 31; on surface casing 12, protection groove 41 is fixed in the outer wall of surface casing 12, and in protection groove 41 was located to second strain sensor 32, fixed protection layer 42 parcel second strain sensor 32, strain sensor protection architecture 40 can play the guard action to first strain sensor 31 and second strain sensor 32, and at well drilling riser pipe 11 and surface casing 12 in-process of going into, can reduce first strain sensor 31 and second strain sensor 32 and receive the damage. The fixed protective layer 42 can be made of glue which can be fixedly connected; the first strain sensor 31 is attached to a protection groove 41 outside the drilling riser 11, and a fixed protection layer 42 is formed in the protection groove 41 and plays a role in fixing and protecting the first strain sensor 31; the second strain sensor 32 is attached to the protective groove 41 outside the surface casing 12, and the fixing protective layer 42 is formed in the protective groove 41 to fix and protect the second strain sensor 32.

The fixing protective layer 42 may have a single-layer structure or a multi-layer structure. Further, the fixing protective layer 42 includes a fixing layer 421, an inner protective layer 422, and an outer protective layer 423. The strain sensor protection structure 40 provided outside the first strain sensor 31 will be described below as an example of the strain sensor protection structure 40.

The protection groove 41 is provided with a groove-shaped channel for arranging the first strain sensor 31 and laying a data transmission line. The protection slot 41 comprises two flat steels 411 which are symmetrically arranged, and a slot-shaped channel is formed between the two flat steels 411; the flat steel 411 in the protection trough is welded to the outer wall of the drilling riser pipe 11.

After the protection groove 41 is welded, marking the fixed position of the first strain sensor 31 in the protection groove 41 according to a preset arrangement point, and polishing the outer wall of the pipe body at the arrangement point by using a polishing tool to remove rust; according to the preset arrangement point, the first strain sensor 31 is adhered and fixed on the outer wall of the drilling riser 11 by using quick adhesive, and the formed quick adhesive is the fixed layer 421. An insulating material layer is arranged between the bare metal wire of the wiring terminal of the first strain sensor 31 and the test tube body to ensure that data transmission is not affected by the metal tube body.

An air-insulating protective layer, i.e., the inner protective layer 422, is formed by coating the outside of the first strain sensor 31 with a quick-stick agent. The quick-adhesion agent can be an AB type quick-adhesion agent, namely the A glue and the B glue are not solidified respectively before mixing and can be solidified after mixing so as to facilitate operation. The inner protection layer 422 is used for protecting the small-range area of the arrangement point of the first strain sensor 31 in a fixed-point mode, plays a role in preliminarily fixing and protecting the first strain sensor 31 in a fixed-point mode, ensures vacuum protection of the first strain sensor 31, avoids air and moisture invasion, and meanwhile, the inner protection layer 422 also plays a role in strengthening and fixing.

After the first strain sensor 31 is fixed by pasting and the data transmission line is laid out, the outer protective layer 423 is constructed. And epoxy resin is poured into the protective groove 41 to form an epoxy resin protective hard layer with the thickness of 2-4 cm, and the epoxy resin protective hard layer is the outer protective layer 423. The outer protective layer 423 plays a role of protection against air; meanwhile, the outer protection layer 423 has a relatively high hardness, and in the process of putting the riser composite pipe string 10 into the soil layer, the outer protection layer 423 can consume the abrasion of the soil layer on the outer wall of the pipe body in the process of putting the riser composite pipe string 10 into the soil layer, so that the first strain sensor 31 and the data transmission line in the protection groove 41 are protected from being damaged.

Preferably, during the process of manufacturing the protection slot 41, a sectional spot welding mode is adopted to avoid large-section welding, so that the bending of the pipe body caused by uneven heating of the drilling riser pipe 11 during the welding process is avoided. As shown in fig. 8, a plurality of partition plates 412 are disposed in the protection slot 41, the partition plates 412 are respectively welded to the flat steel 411 and the outer wall of the drilling riser 11, the partition plates 412 are distributed at intervals along the longitudinal direction 101, the protection slot 41 is divided into a plurality of spaces by the partition plates 412, the fixed protection layer 42 in each separated space is respectively constructed, and the partition plates 412 can provide supporting force along the longitudinal direction 101 for the fixed protection layer 42, so that the stability of the fixed protection layer 42 is ensured, the rigidity of the protection slot 41 is improved, the verticality of the protection slot 41 is ensured, and the bending deformation and detachment of the protection slot 41 in the later-stage piling process are reduced.

The width of the groove-shaped channel of the protection groove 41 may be greater than or equal to the maximum line row width to ensure the orderly arrangement of the data transmission lines. Preferably, the width of the groove-shaped channel is between 4cm and 6cm, the height of the protection groove 41 is between 2cm and 4cm, and on the basis of ensuring enough thickness, the radial area of the protection groove 41 is reduced as much as possible so as to reduce the influence of the protection groove 41 on the stress of the riser composite pipe column 10. After the epoxy resin is filled to form the outer protection layer, a smooth paint surface is brushed on the outer surface of the protection groove 41, so that the friction force between the protection groove 41 and the soil is reduced, and the influence of the protection groove 41 on the bearing capacity of the riser composite pipe column 10 is reduced.

The field operation steps are as follows: (1) firstly, according to a preset arrangement point, marking a fixed position of a first strain sensor 31 in a protective groove 41 welded to a drilling riser pipe 11; (2) polishing the outer wall of the pipe body at the arrangement point by using a polishing tool, wiping alcohol and removing rust of the pipe body; (3) the first strain sensor 31 is fixed at a mark point by using quick adhesive according to a preset direction, an insulating layer is arranged between a metal bare wire at a wiring terminal of the first strain sensor 31 and the outer wall of the pipe body to prevent a measurement electric signal from being influenced by the pipe body of the drilling riser pipe 11, and then an AB quick adhesive is coated on the outer surface of the first strain sensor 31 after the first strain sensor 31 is fixed, so that the fixed point preliminary air isolation protection and fixing effects are achieved; (4) laying a data transmission line, wherein the data transmission line used for the test is preferably in a line row form, welding a reserved lead of a wiring terminal of the first strain sensor 31 with the data transmission line, sleeving a heat-shrinkable tube at a welding joint, baking the heat-shrinkable tube at the joint by using a hot air gun, and quickly and efficiently forming an insulating protection layer; (5) labeling the data line ends of the first strain sensors 31 at the two ends of the pipe body, such as 1-R1 (representing the first strain sensor 31 of the R1 number 1 point), so that the connection can be quickly performed in the later drilling riser pipe 11 connection process; (6) arranging and laying the data transmission lines in the protection groove 41, pouring epoxy resin into the protection groove 41 to reach the upper horizontal surface of the protection groove 41, standing for 12 hours, and waiting for the epoxy resin protection layer to reach absolute strength; (7) after an outer protection layer formed by epoxy resin is kept stand to reach the strength, a lubricating paint surface is brushed on the upper part of the outer protection layer and the outer surface of the protection groove 41, so that the friction effect between the protection groove 41 and soil is reduced, and the influence of the protection groove 41 on the stress of the riser composite pipe column 10 is reduced; (8) the sheet data transmission line at the pile head is connected to the controller 501 in a preset bridge circuit mode, system parameters are adjusted, a test zero point is set, and a test is started.

The strain sensor protective structure 40 outside the first strain sensor 31 has been described above; the strain sensor protection structure 40 outside the second strain sensor 32 is formed on the outer wall of the surface casing 12, and the strain sensor protection structure 40 outside the second strain sensor 32 may refer to the strain sensor protection structure 40 outside the first strain sensor 31, which is not described herein again. The strain sensor protection structure 40 outside the second strain sensor 32 can protect the second strain sensor 32 while the surface casing 12 is being lowered, and can reduce the interference of the impact and heat generated by cement with the second strain sensor 32 while the cement is being poured and set outside the surface casing 12.

In some cases, the riser composite string 10 is of a large length, and during running, the tubular body of the drilling riser 11 and the tubular body of the surface casing 12 need to be spliced section by section. In the process of splicing the pipe body, the data line at the joint of the pipe body needs to be fixed and protected.

The protection measures used will be explained below by taking the drilling riser pipe 11 as an example. The drilling riser pipe 11 comprises an upper pipe body and a lower pipe body to be spliced, and the protection measures are as follows: the length of the protection groove 41 on the upper pipe body is smaller than that of the upper pipe body, and an upper splicing section is reserved at the lower end of the outer wall of the upper pipe body; the length of the protective groove 41 on the lower pipe body is smaller than that of the lower pipe body, and a lower splicing section is reserved at the upper end of the outer wall of the lower pipe body; firstly, after the upper pipe body and the lower pipe body are connected, welding channel steel wire grooves on an upper splicing section and a lower splicing section respectively; the data transmission line of the lower pipe body which enters the mud penetrates through the channel steel wire slot, and the data transmission line in the upper pipe body which does not enter the mud is correspondingly welded according to the number of the label reserved before, the heat-shrinkable pipe is sleeved at the position of the welding joint of the wire, the heat-shrinkable pipe is baked by the hot air gun to quickly form an insulating protective layer, and the insulating protective layer is plugged into the channel steel wire slot, epoxy resin is poured into the channel steel wire slot, and the channel steel wire slot is kept stand for 12 hours, so that the safety of. The positions of the steel wire grooves of the upper pipe body and the lower pipe body are not provided with the arrangement points of the first strain sensor 31, the steel wire grooves of the channel steel can be three steel body protection grooves, and the bottom surfaces of the three steel body protection grooves are welded on the pipe body.

Horizontal loading device

Aiming at a horizontal static force loading experiment, a mode that a gravity block rubs with the ground to provide counter force is adopted.

As shown in fig. 7, the horizontal loading device 50 includes a gravity block and a hydraulic jack 53, the gravity block 61 is stacked on one side of the riser composite pipe string 10, and the hydraulic jack 53 is disposed between the gravity block 61 and the riser composite pipe string 10. The telescopic head of the hydraulic jack 53 extends out of one side of the gravity block 61 until the telescopic head is tightly attached to the gravity block 61, and the oil pressure is adjusted through the hydraulic oil pump, so that the jacking force of the hydraulic jack 53 is controlled, and the jacking force of the hydraulic jack 53 is increased along with the increase of the oil pressure. The gravity block 61 does not slide relatively by virtue of friction between the gravity block 61 and the ground, and according to the force action and reaction principle, the ground provides reverse horizontal force for the gravity block 61 at the moment, and according to the force transmission principle, the horizontal force is transmitted to the side surface of the riser composite pipe column 10 through the hydraulic jack 53 to generate horizontal thrust, so that horizontal static force loading of the riser composite pipe column 10 is realized.

In the field installation step and operation, for the horizontal static loading experiment, a gravity block 61 is first placed near the riser composite string 10 exposed to the surface using a crane, leaving a suitable gap between the two, in order to install the hydraulic jack 53. Installing a hydraulic jack 53; then, an oil pressure pipeline and a control pipeline are connected between the hydraulic jack 53 and the pressure supply pump, and are connected to the controller 501 in a wireless transmission mode, the hydraulic jack 53 is abutted to the riser composite pipe column 10 by adjusting the pressure of the oil pump, adopting a mode of pushing a piston to reciprocate by oil pressure and driving the hydraulic jack 53 to stretch, and accordingly adjusting the hydraulic jack 53 to apply different thrust, and simulating the loading operation of real-time change on site, namely an oil pressure control process; and then, debugging and checking the horizontal loading device 50, pre-loading a small load after the connection of the horizontal loading device 50 is finished, and when the reading of the hydraulic jack 53 is zero (loading starting point) and is in a stable state, finishing the debugging of the instrument, namely, finishing the loading control process.

Further, the horizontal loading device 50 comprises a stacking platform 62, wherein the stacking platform 62 is firstly built on one side of the riser composite pipe column 10, the gravity block 61 is arranged on the stacking platform 62, and then the diesel hydraulic machine and the hydraulic jack 53 are connected, and the hydraulic jack 53 is arranged between the riser composite pipe column 10 and the gravity block 61. Preferably, when the riser pipe composite pipe string is installed, the hydraulic jack 53 is tightly attached to the riser pipe composite pipe string 10, and a gap is reserved between the hydraulic jack 53 and the gravity block 61, so that the hydraulic jack 53 is initially applied with a load, and the hydraulic jack 53 is gradually tightly attached to the gravity block. Specifically, the stowage platform 62 may be formed by splicing a plurality of steel beams.

For horizontal static loading experiments, a counter-force mode is provided by means of the counter-force anchor piles 52.

As shown in fig. 2a and 2b, the horizontal loading device 50 comprises 1 reaction beam 51, 2 reaction anchor piles 52 and hydraulic jacks 53. Arranging a reaction anchor pile 52 and a reaction beam 51 at one side of the riser composite pipe column 10, and then fixing the reaction beam 51 and 2 reaction anchor piles 52 mutually; hydraulic jacks 53 are then placed between the riser composite string 10 and the reaction beams 51.

The thrust of the hydraulic jack 53 is controlled through the hydraulic oil pump, and the hydraulic jack 53 can generate horizontal thrust deviating from the riser composite pipe column 10 to the reaction beam 51; meanwhile, as the 2 reaction anchor piles 52 and the reaction beam 51 are fixed together, according to the force transmission principle and the action force and reaction principle, the reaction anchor piles 52 can generate horizontal thrust in opposite directions to the reaction beam 51, namely the horizontal thrust pointing to the riser composite pipe column 10, and the horizontal thrust is transmitted to the riser composite pipe column 10 through the hydraulic jack 53, namely horizontal static loading of the ultimate bearing capacity experiment of the riser composite pipe column 10 is simulated.

The reaction beam 51 may be made of i-steel. The reaction force beam 51 may be provided between the reaction force anchor pile 52 and the riser composite string 10, the reaction force anchor pile 52 being provided in the longitudinal direction 101, and the reaction force beam 51 being provided in the horizontal direction and perpendicular to the horizontal loading direction 102. Further, the reaction anchor piles 52 are provided with grooves on the side walls thereof, which grooves are engaged with the reaction beams 51, and the reaction beams 51 can be inserted into the grooves, and the reaction beams 51 and the 2 reaction anchor piles 52 are fixed to each other by the grooves.

In the field installation step and operation, aiming at a horizontal static force loading experiment, firstly, groove manufacturing is carried out, a groove with a proper buried depth dimension is dug on the counter-force anchor pile 52 according to the structural dimension of the counter-force beam 51, and the counter-force beam 51 is placed in the groove by a crane; next, the hydraulic jack 53 is placed along a direction perpendicular to the reaction beam 51, and a cushion block with a certain thickness is installed between the hydraulic jack 53 and the reaction beam 51, and the cushion block can be fixed on the reaction beam; then, an oil pressure pipeline and a control pipeline are connected between the hydraulic jack 53 and the oil supply pump, the hydraulic jack is connected to the controller 501 in a wireless transmission mode, the cushion block is tightly jacked by adjusting the pressure of the oil pump, adopting a mode that an oil pressure pushes a piston to reciprocate and drive the hydraulic jack 53 to stretch, the hydraulic jack 53 is tightly clung to the riser composite pipe column 10, different thrust is applied by adjusting the hydraulic jack 53 according to the adjustment, and the loading operation of real-time change on site is simulated, namely the oil pressure control process; and then, debugging and checking the horizontal loading device 50, pre-loading the small load after the connection of the horizontal loading device 50 is finished, and when the reading of the hydraulic jack 53 is zero (loading starting point) and is in a stable state, finishing the debugging of the instrument, namely a loading control process, and finishing the preparation work of the horizontal static ballast experiment in the early stage of loading.

Aiming at the horizontal loading test system of the riser composite pipe column 10 provided by the invention, a better implementation mode is provided.

Firstly, combining the load and constraint conditions borne by the riser composite pipe column 10 under actual working conditions, modeling by using finite element software, and carrying out numerical simulation analysis on the mechanical behavior of the riser composite pipe column to obtain displacement, stress and bending moment cloud charts of the riser composite pipe column 10 in different marine environment reproduction periods, and checking the strength and stability; and then carrying out original dimension experiments of the riser composite pipe column 10, respectively loading by adopting the two horizontal loading devices 50, completing the ultimate bearing capacity experiment of the riser composite pipe column 10, fitting the field reality to a great extent, recording the problems in the experiment process in real time, analyzing and checking the result by combining finite element numerical analysis, analyzing the problems and the development trend in time, providing avoidance measures to the maximum extent, optimizing the loading mode according to the experiment results and aiming at different sea condition conditions, and providing reliable theoretical support and basis for field operation.

Example two

As shown in fig. 6, the method for testing horizontal loading of a riser composite pipe column provided by the invention comprises the following steps: step S10, installing a riser pipe composite pipe column 10, wherein the riser pipe composite pipe column 10 comprises a drilling riser pipe 11, a surface casing pipe 12 arranged in the drilling riser pipe 11 and an annular cement sheath 13 arranged between the drilling riser pipe 11 and the surface casing pipe 12; step S20, arranging first strain sensors 31 along the longitudinal direction 101 on two opposite sides of the outer wall of the drilling riser pipe 11 at the same height in the longitudinal direction; second strain sensors 32 are respectively arranged on two opposite sides of the outer wall of the surface casing 12 at the same height in the longitudinal direction along the longitudinal direction 101; step S30, arranging a horizontal loading device 50 for horizontally and statically loading the pile head of the riser composite pipe column 10 along the horizontal loading direction; step S40, arranging a displacement sensor 20 for measuring the offset of the pile head of the riser pipe composite pipe column 10 at the pile head of the riser pipe composite pipe column 10, wherein the displacement sensor 20 is arranged along the horizontal loading direction 102; step S50, horizontal static force loading is applied, and the magnitude of the pressure of the horizontal static force, the offset of the displacement sensor 20, the magnitude of the strain of the first strain sensor 31, and the magnitude of the strain of the second strain sensor 32 are collected.

The horizontal loading test system of the riser composite pipe column is adopted for carrying out pressure bearing simulation test, horizontal static force is applied to the pile head of the riser composite pipe column 10, the magnitude of the applied horizontal static force ballast is collected, two first strain sensors 31 which are oppositely arranged at the same height respectively detect longitudinal strain, and the bending deformation of the drilling riser 11 can be obtained through the difference value of the two strain sensors; two second strain sensors 32 oppositely arranged at the same height respectively detect the longitudinal strain amount, and the bending deformation amount of the surface casing 12 can be obtained through the difference value of the two strain amounts. The displacement sensor 20 measures the offset of the pile head of the riser composite string 10. The offset of pile head can be known, well drilling riser pipe 11 is along fore-and-aft strain, the surface casing is along fore-and-aft strain, and well drilling riser pipe 11's bending deformation and surface casing 12's bending deformation, and the relation between the size of the quiet power loading of level, thereby judge the loaded limit bearing capacity value of the quiet power of level that riser pipe composite string 10 can bear, the degree of accuracy of the limit bearing capacity value that the test was obtained has been improved, according to this limit bearing capacity value, be favorable to providing economy for well drilling shaft structural design, scientific and reasonable riser pipe composite string 10 income mud degree of depth, guarantee well drilling riser pipe 11 and the stable safety of well head.

In step S50, a horizontal static force may be applied to the pile head of the riser composite pipe string 10 by adjusting the pressure value of the hydraulic jack 53. Be connected with load sensor on the hydraulic jack, the data of gathering include: the pressure signal which represents the horizontal static force loading magnitude of the pile head of the riser composite pipe string 10 and is collected by the load sensor, the displacement signal which represents the pile head offset of the riser composite pipe string 10 and is collected by the displacement sensor 20, and the strain signal which represents the pile body deformation of the riser composite pipe string 10 and is collected by the first strain sensor 31 and the second strain sensor 32.

Further, in step S50, horizontal static loading is applied in a stepwise increasing manner; step S50 includes:

step S51, setting the judgment condition of the limit bearing capacity of the pile head;

step S52, increasing the pressure of the applied horizontal static force loading step by step, stopping increasing the horizontal static force loading when the pile head limit bearing capacity judgment condition is reached, and collecting the pressure of the horizontal static force, the pile head displacement of the displacement sensor 20, the strain of the first strain sensor 31 and the strain of the second strain sensor 32.

The measured value of the pile head offset can be used as a basis for judging the ultimate bearing capacity value of the riser composite pipe column 10 by combining the loading load condition. Condition a: when the offset of the pile head loaded at the stage is 4 times larger than that of the pile head under the action of the load of the previous stage, the offset exceeds 0.1mm/15 min; condition B: when the total accumulated offset of the pile head reaches 40mm or the maximum allowable offset value required by the design. The above-mentioned pile head ultimate bearing capacity determination condition is that any one of the condition a or the condition B is satisfied, and at this time, the riser composite pipe column 10 reaches the ultimate bearing capacity.

Specifically, in step S51, the parameters set include: the pile head loading stage number, the single increase of the pile head load and the judgment condition of the limit bearing capacity of the pile head are stored in the controller 501. In step S52, the controller increases the pressure value of the hydraulic pump step by adjusting the predetermined loading step, continuously acquires the signal of the displacement sensor 20 after adjusting the pile head load value each time and feeds the signal back to the controller, and compares the offset signal with the limit bearing capacity determination condition. If the pile head offset signal fed back by the pile head displacement sensor 20 does not reach the preset limit bearing capacity judgment condition, the controller performs a next-stage loading program according to the preset loading step, and the process is circulated until the feedback signal reaches the preset limit bearing capacity judgment condition, the loading step is stopped, and the limit bearing capacity value of the riser composite pipe column 10 is read.

Further, the pile body surface strain quantity and the pile head offset quantity of the drilling riser 11 and the surface casing 12 are continuously measured in the process of applying horizontal static ballast, so that the deformation condition of the drilling riser composite pipe column 10 under the horizontal static ballast can be conveniently known.

The above description is only a few embodiments of the present invention, and those skilled in the art can make various changes or modifications to the embodiments of the present invention according to the disclosure of the application document without departing from the spirit and scope of the present invention.

Claims (14)

1. A horizontal loading test system of a riser composite pipe column is used for carrying out horizontal loading test on the riser composite pipe column, and the riser composite pipe column comprises a drilling riser, a surface casing arranged in the drilling riser, and an annular cement sheath arranged between the drilling riser and the surface casing; characterized in that the test system comprises:

the horizontal loading device is used for horizontally and statically loading the pile head of the riser composite pipe column;

the displacement sensor is arranged at the pile head of the riser pipe composite pipe column along the horizontal loading direction and is used for measuring the offset of the pile head of the riser pipe composite pipe column;

the first strain sensors are arranged along the longitudinal direction, and are respectively arranged on two opposite sides of at least one position of the drilling riser pipe at the same height in the longitudinal direction;

and the second strain sensors are arranged along the longitudinal direction, and the second strain sensors are respectively arranged on two opposite sides of at least one longitudinal position of the surface sleeve at the same height.

2. The system of claim 1, wherein the testing system comprises a fixed displacement reference beam perpendicular to the horizontal loading direction, the displacement sensor comprises a fixed end and a measuring end, and the fixed end and the measuring end are respectively connected with the pile head of the riser composite pipe column and the displacement reference beam in a one-to-one correspondence manner.

3. The horizontal loading test system of the riser composite string of claim 2, wherein the displacement reference beam is provided with a flow channel for liquid to flow, and the flow channel is provided with a water outlet and a water inlet.

4. The horizontal loading test system of the riser composite pipe column of claim 1, wherein the outer wall of the drilling riser is provided with a strain sensor protection structure, and the strain sensor protection structure comprises a protection groove and a fixed protection layer fixedly connected in the protection groove;

on the drilling riser pipe, the protection groove is fixed in the outer wall of the drilling riser pipe, the first strain sensor is arranged in the protection groove, and the fixed protection layer wraps the first strain sensor.

5. The horizontal loading test system of the riser composite pipe column according to claim 4, wherein the fixed protection layer is of a multilayer structure and comprises a fixed layer, an inner protection layer and an outer protection layer, the fixed layer is arranged between the outer wall of the drilling riser and the first strain sensor, the inner protection layer and the outer protection layer are sequentially distributed from inside to outside, and the outer protection layer is made of epoxy resin.

6. The horizontal loading test system of the riser composite pipe column of claim 1, wherein the outer wall of the surface casing is provided with a strain sensor protection structure, and the strain sensor protection structure comprises a protection groove and a fixed protection layer fixedly connected in the protection groove;

on the surface casing pipe, the protection groove is fixed in the outer wall of surface casing pipe, the second strain sensor is located in the protection groove, fixed protective layer parcel the second strain sensor.

7. The horizontal loading test system of the riser composite pipe column according to claim 6, wherein the fixed protective layer is of a multilayer structure and comprises a fixed layer, an inner protective layer and an outer protective layer, the fixed layer is arranged between the outer wall of the surface casing and the second strain sensor, the inner protective layer and the outer protective layer are sequentially distributed from inside to outside, and the outer protective layer is made of epoxy resin.

8. The riser composite pipe string horizontal loading test system of claim 4 or claim 6, wherein the strain sensor protection structure comprises a plurality of partition plates disposed in the protection groove, the partition plates are fixedly connected to the inner wall of the protection groove, and the plurality of partition plates are distributed at intervals along the longitudinal direction.

9. The system of claim 1, wherein the horizontal loading device comprises a reaction beam, an anchor pile and a hydraulic jack, the anchor pile is fixedly arranged on one side of the riser composite pipe string, the reaction beam is connected with the anchor pile, the anchor pile can prevent the reaction beam from moving along the direction of horizontal loading, and the hydraulic jack is arranged between the riser composite pipe string and the reaction beam along the direction of horizontal loading and can stretch to abut against the riser composite pipe string and the reaction beam respectively.

10. The system of claim 1, wherein the horizontal loading device comprises a gravity block and a hydraulic jack, the gravity block is disposed on one side of the riser composite pipe string, the hydraulic jack is disposed between the riser composite pipe string and the gravity block along the horizontal loading direction and can extend and retract to abut against the riser composite pipe string and the gravity block, and the gravity block can prevent the hydraulic jack from moving in the reverse direction along the horizontal loading direction by virtue of friction.

11. A horizontal loading test method for a riser composite pipe column is characterized by comprising the following steps:

step S10, installing a riser pipe composite pipe column, wherein the riser pipe composite pipe column comprises a drilling riser pipe, a surface casing pipe arranged in the drilling riser pipe and an annular cement sheath arranged between the drilling riser pipe and the surface casing pipe;

step S20, arranging first strain sensors on two opposite sides of the outer wall of the drilling riser pipe at the same height in the longitudinal direction respectively along the longitudinal direction; second strain sensors are respectively arranged on two opposite sides of the outer wall of the surface layer sleeve at the same height in the longitudinal direction along the longitudinal direction;

step S30, arranging a horizontal loading device for horizontally and statically loading the pile head of the riser composite pipe column along the horizontal loading direction;

step S40, arranging a displacement sensor for measuring the offset of the pile head of the riser pipe composite pipe column at the pile head of the riser pipe composite pipe column, wherein the displacement sensor is arranged along the horizontal loading direction;

and step S50, the horizontal loading device applies horizontal static force loading to the pile head of the riser composite pipe column, and the pressure of the horizontal static force, the offset of the displacement sensor, the strain of the first strain sensor and the strain of the second strain sensor are collected.

12. The method for testing horizontal loading of a riser composite string as claimed in claim 11, wherein the step S40 comprises: a displacement reference beam is fixedly arranged and is vertical to the horizontal loading direction, and the fixed end and the measuring end of the displacement sensor are respectively connected with the pile head of the riser composite pipe column and the displacement reference beam; the displacement reference beam is provided with a circulation groove for liquid to flow, and the circulation groove is provided with a water outlet and a water inlet.

13. The method of claim 11, wherein the horizontal loading device comprises a reaction beam, an anchor pile and a hydraulic jack, the anchor pile is fixedly arranged on one side of the riser composite pipe string, the reaction beam is connected with the anchor pile, the anchor pile can prevent the reaction beam from moving in the direction of horizontal loading, and the hydraulic jack is arranged between the riser composite pipe string and the reaction beam in the direction of horizontal loading and can extend and retract to abut against the riser composite pipe string and the reaction beam respectively.

14. The method for testing horizontal loading of a riser composite string as claimed in claim 11, wherein in step S50, horizontal static loading is applied in a stepwise increasing manner; the step S50 includes:

step S51, setting the judgment condition of the limit bearing capacity of the pile head;

and step S52, increasing the pressure of the applied horizontal static force loading step by step, stopping increasing the horizontal static force loading when the pile head limit bearing capacity judgment condition is reached, and acquiring the pressure of the horizontal static force, the offset of the displacement sensor, the strain of the first strain sensor and the strain of the second strain sensor.

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