Metal plugging device based on carbon-based composite phase change material and use method

Abstract

The invention relates to the technical field of petroleum and natural gas exploration and development, in particular to a metal plugging device based on a carbon-based composite phase-change material and a use method.The metal plugging device comprises a headstall, a positioner, a weighting rod, a conversion nipple and a phase-change metal bridge plug tool assembly which are sequentially connected together from top to bottom; the phase change metal bridge plug tool assembly comprises an excitation short section, a phase change pipe, a connecting rod, a bearing short section and a bottom plug. The phase change pipe is reasonable and compact in structure, when the phase change pipe is used, the phase change pipe can be changed from a solid state to a liquid state by exciting the short section and then is filled in an oil pipe or a casing annulus, then the phase change pipe is changed from the liquid state to the solid state to seal the oil pipe or the casing annulus, and a limited space needing to be plugged, especially a corroded well section, is completely filled; the plugging device improves the reliability of plugging in an oil pipe or a sleeve, reduces the limitation of well condition change on plugging construction of the phase change pipe, and has the advantages of high pressure bearing capacity, simplicity, convenience and rapidness in operation, acid corrosion resistance and wide application range.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration and development, and is a metal plugging device based on a carbon-based composite phase change material and a usage method thereof. Background Art

[0002] During the exploration and development of oil and gas fields, bridge plugs, as essential downhole plugging tools, are widely used in fields such as well testing, gas testing, workover, testing, oil and gas reservoir stimulation, and reservoir plugging. The currently used bridge plugs for plugging in oil and casing pipes often adopt an upper and lower double slip + rubber barrel structure. During the setting process of such bridge plugs, the slips are opened to bite with the oil and casing pipes, and the rubber barrel is compressed and expanded to fit the inner wall of the oil and casing pipes for sealing. Under the clamping of the upper and lower slips, the rubber barrel maintains a compressed and expanded sealing state, thereby plugging the oil and casing pipes.

[0003] The structural design of such bridge plugs is relatively complex, and there are numerous sizes and specifications. Sometimes, for oil and casing pipes with the same outer diameter, due to different wall thicknesses and steel grades of the oil and casing pipes, bridge plugs with different specifications and sizes need to be used, causing many inconveniences to on-site construction. In addition, the double slip rubber barrel sealing structure has high requirements for the inner wall state of the oil and casing pipes. Otherwise, the sealing effect cannot be guaranteed after the bridge plug is set, especially in severely corroded well sections, and even the setting of the bridge plug cannot be achieved. For old wells that have been produced for many years, the pipe strings have varying degrees of corrosion, and the inner diameter and wall thickness of the setting section have also changed to varying degrees. When using such bridge plugs for plugging, effective sealing is often impossible to achieve.

[0004] With the increasing domestic demand for oil and gas, the development of oil and gas fields has entered a new stage. Some complex oil and gas reservoirs with high temperature, high pressure, and high sulfur content have gradually been explored and developed, which puts higher requirements on downhole tools, and requires them to ensure long-term reliability in more demanding environments. For most of the currently used bridge plugs, the material of the slips is cast iron, and the material of the rubber barrel is rubber. Under harsh conditions (high temperature, high pressure, high sulfur content), the relevant properties of such materials will change. For example, hydrogen sulfide can not only corrode the surface of steel, but also cause changes in the internal structure of steel, resulting in a decrease in its performance. High temperature will cause changes in the physical properties of rubber, such as changes in hardness and a decrease in tensile strength.

[0005] In addition, the setting of some bridge plugs requires the use of pyrotechnics, and the use of pyrotechnics also poses very great safety restrictions on the plugging operation of the bridge plug. Summary of the Invention

[0006] The present invention provides a metal plugging device based on a carbon-based composite phase change material and a usage method thereof, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems that the existing bridge plugs have high requirements for the inner wall state of the oil and casing pipes, poor reliability under harsh conditions, and limited use.

[0007] One of the technical solutions of the present invention is achieved by the following measures: A metal plugging device based on a carbon-based composite phase change material, comprising a gooseneck, a locator, a weight rod, a crossover sub, and a phase change metal bridge plug tool assembly connected together from top to bottom in sequence. The phase change metal bridge plug tool assembly includes an activation sub, a phase change tube, a connecting rod, a receiving sub, and a bottom plug. The lower end of the crossover sub is fixedly installed with the upper end of the activation sub. The connecting rod is installed inside the lower end of the activation sub. A plurality of shear pins installed with the connecting rod are arranged at intervals along the circumference on the outer side of the lower end of the activation sub. The lower end of the connecting rod is fixedly installed with the upper end of the receiving sub. The bottom plug is hermetically and fixedly installed at the lower end of the receiving sub. A phase change tube is provided on the outer side of the connecting rod corresponding to the position between the lower end of the activation sub and the upper end of the receiving sub. The phase change tube can be transformed from a solid state to a liquid state when the activation sub is electrified, and the phase change tube can be transformed from a liquid state to a solid state when the activation sub is powered off.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions of the invention: The above may further include a ground control unit and a connecting cable, and the ground control unit is connected to the upper end of the gooseneck through the connecting cable.

[0009] The above locator can be a magnetic locator.

[0010] A connecting sub screwed onto the outer side of the lower part of the above activation sub and sleeved on the outer side of the upper part of the phase change tube may be provided. A plurality of radially penetrating mounting screw holes are evenly distributed at intervals along the circumference on the outer side of the lower part of the connecting sub. An outward-opening mounting groove is provided on the outer side of the connecting rod corresponding to each mounting screw hole. A shear pin with an end located in the corresponding mounting groove is screwed into each mounting screw hole. The phase change tube is sleeved on the outer side of the connecting rod between the lower end of the connecting sub and the upper end of the receiving sub.

[0011] Another technical solution of the present invention is achieved by the following measures: A method for using a metal plugging device based on a carbon-based composite phase change material, comprising the following steps: Step 1: Lower the phase change tube to the target depth in the well. Step 2: Check the depth of the phase change tube through the locator to determine the setting depth. Step 3: After the activation sub is electrified and starts to work, the phase change tube flows downward after being transformed from a solid state to a liquid state and fills the annulus between the outer side of the connecting rod and the inner side of the casing or tubing after reaching the upper end of the receiving sub. Step 4: After the activation sub works for a certain period of time, it is powered off and stops working. The phase change tube is transformed from a liquid state to a solid state, sealing the outer side of the connecting rod and the inner wall of the tubing or casing. Step 5: Lift the gooseneck. After the shear pins are cut off, the activation sub is retrieved to complete the setting operation of the tubing or casing.

[0012] The following is a further optimization and / or improvement of the above-mentioned technical solution of the invention: The first step above is to lower the phase change pipe to the target depth in the well through a cable winch and a connecting cable.

[0013] The second step above is to perform depth correction through a magnetic locator after the phase change pipe is lowered to the target depth in the well to determine the setting depth.

[0014] The fourth step above is that after the setting depth is confirmed, the ground control unit makes the firing nipple energized through the connecting cable to start working. After the phase change pipe changes from solid state to liquid state, it flows downward to the upper end of the receiving nipple and fills the annulus between the outside of the connecting rod and the inside of the casing or tubing.

[0015] The structure of the present invention is reasonable and compact. When in use, through the firing nipple, the phase change pipe can change from solid state to liquid state and then fill the annulus of the tubing or casing. Then, the phase change pipe changes from liquid state to solid state to form a seal for the annulus of the tubing or casing, completely filling the defined space to be blocked, especially including the corroded well section, improving the reliability of the plugging in the tubing or casing, reducing the limitation of well condition changes on the plugging construction of the phase change pipe, and having the advantages of high pressure-bearing capacity, simple and fast operation, acid corrosion resistance, and wide application range. Brief Description of the Drawings

[0016] Attached Figure 1 is the front view structural schematic diagram of Embodiment 1 to Embodiment 6.

[0017] Attached Figure 2 is for the attached Figure 1 front view sectional structural schematic diagram of the phase change pipe in it.

[0018] Attached Figure 3 is for the attached Figure 1 front view sectional structural schematic diagram of the position where the phase change pipe is lowered and set in it.

[0019] Attached Figure 4 is for the attached Figure 1 front view sectional structural schematic diagram of the phase change pipe after being set in it.

[0020] Attached Figure 5 is for the attached Figure 1 front view sectional structural schematic diagram of the phase change pipe after the shear pin is cut off in it.

[0021] The codes in the drawings are respectively: 1 is the pony head, 2 is the magnetic locator, 3 is the heavy rod, 4 is the conversion nipple, 5 is the firing nipple, 6 is the phase change pipe, 7 is the connecting rod, 8 is the receiving nipple, 9 is the bottom plug, 10 is the shear pin, 11 is the ground control unit, 12 is the connecting cable, and 13 is the connecting nipple. Detailed Description of the Invention

[0022] The present invention is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solution of the present invention and the actual situation.

[0023] In the present invention, for the convenience of description, the description of the relative positional relationship of each component is carried out according to the layout mode of the accompanying drawings of the specification. For example, the positional relationships such as front, rear, upper, lower, left, and right are determined according to the layout direction of the accompanying drawings of the specification. Figure 1 The positional relationships such as front, rear, upper, lower, left, and right are determined according to the layout direction of the accompanying drawings of the specification.

[0024] The present invention will be further described below in conjunction with embodiments and the accompanying drawings: Embodiment 1: As shown in the attached Figure 1 、 2 , the metal plugging device based on the carbon-based composite phase change material includes a gooseneck 1, a locator, a weight rod 3, a crossover sub 4, and a phase change metal bridge plug tool assembly that are connected together in sequence from top to bottom. The phase change metal bridge plug tool assembly includes an activation sub 5, a phase change tube 6, a connecting rod 7, a receiving sub 8, and a bottom plug 9. The lower end of the crossover sub 4 is fixedly installed with the upper end of the activation sub 5. Inside the lower end of the activation sub 5, a connecting rod 7 is installed. Along the circumference at intervals outside the lower end of the activation sub 5, a plurality of shear pins 10 installed with the connecting rod 7 are provided. The lower end of the connecting rod 7 is fixedly installed with the upper end of the receiving sub 8. The lower end of the receiving sub 8 is hermetically and fixedly installed with a bottom plug 9. Outside the connecting rod 7 at the position between the lower end of the activation sub 5 and the upper end of the receiving sub 8, a phase change tube 6 is provided. The phase change tube 6 can be changed from a solid state to a liquid state when the activation sub 5 is energized, and the phase change tube 6 can be changed from a liquid state to a solid state when the activation sub 5 is de-energized.

[0025] According to requirements, the material of the phase change tube 6 is a well-known metal phase change material in the prior art, and the activation sub 5 is a well-known technology in the prior art, such as a heater. During use, through the activation sub 5, the phase change tube 6 can be changed from a solid state to a liquid state and then filled in the annulus between the tubing and the casing. Then, the phase change tube 6 is changed from a liquid state to a solid state to form a seal for the annulus between the tubing and the casing, completely filling the defined space to be plugged, especially including the corroded well section, improving the reliability of plugging in the tubing or casing, reducing the limitation of well condition changes on the plugging construction of the phase change tube 6, and having the advantages of high pressure-bearing capacity, simple and quick operation, acid corrosion resistance, and wide application range.

[0026] According to actual needs, the above-mentioned metal plugging device based on the carbon-based composite phase change material can be further optimized and / or improved: Embodiment 2: As an optimization of the above embodiment, as shown in the attached Figure 1As shown in the figure, it further includes a ground control unit 11 and a connecting cable 12. The ground control unit 11 is connected to the upper end of the pony head 1 through the connecting cable 12. According to requirements, the ground control unit 11 is a known prior art. By energizing the firing sub 5 through the ground control unit 11 and the connecting cable 12, the tubing annulus or the casing annulus can be set, without the need for other power sources. It overcomes the deficiencies of the existing bridge plug setting technology and effectively solves the problems existing in traditional bridge plugs, such as a large variety of specifications and dimensions, high requirements for the inner walls of oil and casing pipes, poor sealing in the corrosion section or inability to set, unsealing under harsh conditions, and the use of pyrotechnic devices.

[0027] Embodiment 3: As an optimization of the above embodiment, as shown in the appendix Figure 1 As shown in the figure, the locator is a magnetic locator 2. According to requirements, the magnetic locator 2 is a known prior art. It can accurately determine the position of the phase change pipe 6 in the well according to the casing collar curve and in cooperation with the radioactive logging curve, improving the accuracy of setting the tubing annulus or the casing annulus.

[0028] Embodiment 4: As an optimization of the above embodiment, as shown in the appendix Figure 1 、 2 As shown in the figure, a connecting sub 13 sleeved on the outer side of the upper part of the phase change pipe 6 is screwed on the outer side of the lower part of the firing sub 5. A plurality of radially penetrating mounting screw holes are evenly distributed at intervals along the circumference on the outer side of the lower part of the connecting sub 13. An outward-opening mounting groove is provided on the outer side of the connecting rod 7 corresponding to each mounting screw hole. A shear pin 10 with an end located in the corresponding mounting groove is screwed in each mounting screw hole. The phase change pipe 6 is sleeved on the outer side of the connecting rod 7 between the lower end of the connecting sub 13 and the upper end of the receiving sub 8.

[0029] During use, with such a setting, it is convenient for the quick disassembly and assembly between the phase change pipe 6 and the firing sub 5. The material and quantity of the shear pins 10 can be determined according to the specifications of the connecting cable 12, the setting depth, and the dimensions of the tubing or the casing. After the phase change pipe 6 deforms, the tubing annulus or the casing annulus is set to achieve the metal seal of the tubing or the casing annulus and improve the setting effect. By setting the shear pins 10, after the tubing annulus or the casing annulus is set, when the pony head is lifted, the shear pins 10 can be cut off, so that the connecting rod 7 is separated from the firing sub 5 to complete the releasing operation.

[0030] Embodiment 5: As an optimization of the above embodiment, as shown in the appendix Figures 1 to 5 As shown in the figure, the usage method of the metal plugging device based on the carbon-based composite phase change material includes the following steps: Step 1, lower the phase change pipe 6 to the target depth in the well; Step 2, check the depth of the phase change pipe 6 through the locator to determine the setting depth; Step 3: After the activation sub 5 is energized and starts to work, the phase change tube 6 changes from solid state to liquid state and then flows downward to the upper end of the receiving sub 8 to fill the annulus between the outer side of the connecting rod 7 and the inner side of the casing or tubing; Step 4: After the activation sub 5 works for a certain period of time, it is powered off and stops working. The phase change tube 6 changes from liquid state to solid state, sealing the outer side of the connecting rod 7 and the inner wall of the tubing or casing; Step 5: Lift the swivel 1. After the shear pin 10 is cut off, the activation sub 5 is removed, completing the setting operation of the tubing or casing.

[0031] The difference from the traditional bridge plugging is that the traditional bridge plugging method uses the setting force generated by the bridge plug setting tool to open the slips and bite with the oil casing, and the rubber barrel is compressed and expanded to fit the inner wall of the oil casing for sealing. In the present invention, through the activation sub 5, using the properties of the phase change tube 6, it undergoes a "solid-liquid-solid" transformation, and then, by utilizing the high specific gravity characteristic of the phase change material in the phase change tube 6, the limited space to be plugged is completely filled. After curing, a metal-to-metal sealing effect is achieved.

[0032] According to actual needs, the usage method of the above metal plugging device based on carbon-based composite phase change materials can be further optimized and / or improved: Example 6: As an optimization of the above example, as shown in the appendix Figures 1 to 5 Step 1: Lower the phase change tube 6 to the target depth in the well through the cable winch and the connecting cable 12; Step 2: After the phase change tube 6 is lowered to the target depth in the well, depth correction is performed through the magnetic locator 2 to determine the setting depth; Step 4: After the setting depth is confirmed, the ground control unit 11 energizes the activation sub 5 through the connecting cable 12 to start working. The phase change tube 6 changes from solid state to liquid state and then flows downward to the upper end of the receiving sub 8 to fill the annulus between the outer side of the connecting rod 7 and the inner side of the casing or tubing.

[0033] The phase change tube 6 is transported to the target well section by the connecting cable 12. The setting position is determined by the magnetic locator 2, and then the ground control unit 11 supplies power to start the activation sub 5. Through the work of the activation sub 5, the phase state transformation of the material of the phase change tube 6 is realized. Since the phase change metal material has a high specific gravity characteristic, when the phase change metal material is transformed into a liquid state, it can quickly fill the entire cross-section of the tubing or casing at the setting position. At this time, the power supply is stopped, and the activation sub 5 stops working, waiting for the phase change metal material to solidify. The solidified phase change metal material can then form a metal-to-metal seal with the tubing or casing annulus, completing the setting operation of the tubing or casing.

[0034] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A metal plugging device based on a carbon-based composite phase change material, characterized in that it includes a gooseneck, a locator, a weight rod, a crossover sub, and a phase change metal bridge plug tool assembly connected together in sequence from top to bottom. The phase change metal bridge plug tool assembly includes an activation sub, a phase change tube, a connecting rod, a receiving sub, and a bottom plug. The lower end of the crossover sub is fixedly installed with the upper end of the activation sub. The inner side of the lower end of the activation sub is provided with a connecting rod. A plurality of shear pins installed with the connecting rod are arranged at intervals along the circumference on the outer side of the lower end of the activation sub. The lower end of the connecting rod is fixedly installed with the upper end of the receiving sub. The lower end of the receiving sub is hermetically and fixedly installed with a bottom plug. A phase change tube is provided on the outer side of the connecting rod corresponding to the position between the lower end of the activation sub and the upper end of the receiving sub. The phase change tube can be changed from a solid state to a liquid state when the activation sub is energized, and the phase change tube can be changed from a liquid state to a solid state when the activation sub is de-energized.

2. The metal plugging device based on a carbon-based composite phase change material according to claim 1, characterized in that it further includes a ground control unit and a connecting cable, and the ground control unit is connected to the upper end of the gooseneck through the connecting cable.

3. The metal plugging device based on a carbon-based composite phase change material according to claim 1 or 2, characterized in that the locator is a magnetic locator.

4. The metal plugging device based on a carbon-based composite phase change material according to claim 1 or 2, characterized in that a connecting sub sleeved on the outer side of the upper part of the phase change tube is screwed on the outer side of the lower part of the activation sub. A plurality of radially penetrating mounting screw holes are evenly distributed at intervals along the circumference on the outer side of the lower part of the connecting sub. An outward-opening mounting groove is provided on the outer side of the connecting rod corresponding to each mounting screw hole. A shear pin with an end located in the corresponding mounting groove is screwed in each mounting screw hole. The phase change tube is sleeved on the outer side of the connecting rod between the lower end of the connecting sub and the upper end of the receiving sub.

5. The metal plugging device based on a carbon-based composite phase change material according to claim 3, characterized in that a connecting sub sleeved on the outer side of the upper part of the phase change tube is screwed on the outer side of the lower part of the activation sub. A plurality of radially penetrating mounting screw holes are evenly distributed at intervals along the circumference on the outer side of the lower part of the connecting sub. An outward-opening mounting groove is provided on the outer side of the connecting rod corresponding to each mounting screw hole. A shear pin with an end located in the corresponding mounting groove is screwed in each mounting screw hole. The phase change tube is sleeved on the outer side of the connecting rod between the lower end of the connecting sub and the upper end of the receiving sub.

6. A method for using the metal plugging device based on a carbon-based composite phase change material according to any one of claims 1 to 5, characterized in that it includes the following steps: Step 1, lowering the phase change tube into the target depth in the well; Step 2, checking the depth of the phase change tube through the locator to determine the setting depth; Step 3, after the activation sub is energized and starts to work, the phase change tube flows downward after changing from a solid state to a liquid state and fills the annulus between the outer side of the connecting rod and the inner side of the casing or tubing after reaching the upper end of the receiving sub; Step 4, after the activation sub works for a certain period of time, it is de-energized and stops working. The phase change tube changes from a liquid state to a solid state and seals the outer side of the connecting rod and the inner wall of the tubing or casing; Step 5, lifting the gooseneck, after the shear pins are cut off, lifting out the activation sub to complete the setting operation of the tubing or casing.

7. The usage method of the metal plugging device based on the carbon-based composite phase change material according to claim 5, characterized in that Step 1 is to lower the phase change pipe to the target depth in the well through a cable winch and a connecting cable.

8. The usage method of the metal plugging device based on the carbon-based composite phase change material according to claim 6 or 7, characterized in that Step 2 is, after the phase change pipe is lowered to the target depth in the well, to perform depth correction through a magnetic locator to determine the setting depth.

9. The usage method of the metal plugging device based on the carbon-based composite phase change material according to claim 6 or 7, characterized in that Step 4 is, after the setting depth is confirmed, the ground control unit makes the firing nipple energized through the connecting cable to start working. After the phase change pipe changes from solid state to liquid state, it flows downward to the upper end of the receiving nipple and then fills the annulus between the outer side of the connecting rod and the inner side of the casing or tubing.

10. The usage method of the metal plugging device based on the carbon-based composite phase change material according to claim 8, characterized in that Step 4 is, after the setting depth is confirmed, the ground control unit makes the firing nipple energized through the connecting cable to start working. After the phase change pipe changes from solid state to liquid state, it flows downward to the upper end of the receiving nipple and then fills the annulus between the outer side of the connecting rod and the inner side of the casing or tubing.

Images