Metal packer

Abstract

The invention provides a metal packer which comprises a mandrel. The metal sealing element is arranged outside the core shaft, and the metal sealing element and underground liquid can generate metal swelling, so that an annular space between the core shaft and the casing pipe is sealed and separated; an elastic enveloping body is arranged on the outer side of the metal sealing element, and deformable combined supporting mechanisms are arranged at the two ends of the metal sealing element; the elastic enveloping body and the deformable combined supporting mechanism are wrapped outside the metal sealing element to form an expansion space. Annulus packing is achieved according to the principle that the size of metal or alloy becomes large after hydration reaction, the structure is simple, operation is convenient, setting reliability is high, well adaptability is high, the technical requirements for high-pressure annulus packing of an ultra-high-temperature well and a small-gap well can be met, and construction safety, reliability and efficiency are improved.

Description

Technical Field

[0001] The present invention relates to a metal packer, in particular to a packer based on metal hydration reaction swelling, and relates to the field of petroleum well completion downhole tools. Background Art

[0002] Packers are commonly used tools in oil drilling and completion, used to isolate the annulus between the casing and tubing, or between the casing and wellbore. Existing packer sealing elements are primarily made of rubber or specialized metals, achieving annular isolation through physical methods such as mechanical compression or hydraulic expansion. For example, compression packers achieve annular isolation by mechanically or hydraulically compressing the rubber cartridge axially, causing it to expand radially.

[0003] Traditional metal expansion packers utilize a cone sleeve to compress, causing the metal ring to plastically deform, driving the rubber element to expand radially to isolate the annulus. However, these packers rely on the excellent physical properties of rubber, such as elasticity and elongation, to achieve annular isolation. However, elastomers like rubber experience performance degradation under harsh conditions such as high temperature, high pressure, and high salinity, making them unable to meet the demands of long-term downhole high-temperature and high-pressure applications (>200°C / 70MPa). Failure of the packer can lead to the suspension or failure of oil and gas well construction or production, resulting in significant losses.

[0004] Some metal packers utilize a chemical hydration reaction between metal and brine to produce water-insoluble oxides or hydroxides. These products significantly increase in volume compared to the original metal, thus acting as sealing elements to isolate the annulus. However, since these packers achieve metal swelling through a chemical reaction, ensuring that the metal expands primarily radially, rather than axially, is crucial to achieving high-pressure isolation. Summary of the Invention

[0005] In response to the above-mentioned technical problems existing in the prior art, the present invention proposes a metal packer, whose sealing element is made of special metal or alloy material, and realizes annular space isolation through the principle that the volume of the metal or alloy increases after the hydration reaction. It adopts the design of elastic envelope, segmented modular support and end deformable combined support mechanism to prevent disordered diffusion of metal after swelling, thereby improving the pressure bearing capacity of the packer, so that the packer can meet the cementing and completion requirements of ultra-high temperature oil and gas wells such as ultra-deep wells, geothermal wells and hot dry rocks.

[0006] The present invention provides a metal packer, comprising:

[0007] Mandrel;

[0008] a metal sealing element disposed on the outside of the mandrel, wherein the metal sealing element is capable of swelling with downhole fluid to seal the annulus between the mandrel and the casing; and

[0009] Among them, an elastic envelope is provided on the outside of the metal sealing element, and deformable combined support mechanisms are provided at both ends of the metal sealing element; the elastic envelope and the deformable combined support mechanism are wrapped around the outside of the metal sealing element to form an expansion space.

[0010] A further improvement of the present invention is that the metal sealing element is a cylindrical, one-piece structure.

[0011] A further improvement of the present invention is that the metal sealing element comprises several sections, and several segmented support rings are arranged in the middle.

[0012] A further improvement of the present invention is that the deformable combined support mechanism includes a pressure ring, the pressure ring includes a connecting portion in contact with the metal sealing element, and a fixing portion arranged on a side away from the metal sealing element;

[0013] The connecting portion is relatively thick, and forms an annular space with the core shaft, and the metal sealing element is pressed in the space; the fixing portion is relatively thin.

[0014] A further improvement of the present invention is that a protective sleeve is provided on the outer side of the pressure ring.

[0015] A further improvement of the present invention is that the deformable combined support mechanism further includes multiple layers of deformable limiting rings.

[0016] A further improvement of the present invention is that the protective sleeve is made of a soluble material, which can dissolve in a saline environment and lose strength, thereby allowing the multi-layer deformable limiting ring and the pressure ring to expand radially, providing expansion space for the metal sealing element.

[0017] A further improvement of the present invention is that the multi-layered variable diameter elastic ring comprises at least two layers of variable diameter elastic rings;

[0018] The variable diameter elastic ring includes a main body covering the outer side of the fixed portion of the pressure plate, and a fixed cylinder end connected to the core shaft;

[0019] The main body is provided with a plurality of opening grooves, which divide the main body into a plurality of elastic ribs; the opening grooves of the variable diameter elastic rings in different layers are staggered.

[0020] A further improvement of the present invention is that the end of the pressure ring is fixed to the core shaft via a fixing ring.

[0021] A further improvement of the present invention is that end rings are provided at both ends of the metal sealing element, the end rings are fixed on the core shaft and are capable of blocking the metal sealing element;

[0022] The end ring prevents the metal sealing element from expanding in the axial direction of the core shaft when expanding, while ensuring that the metal sealing element expands in the radial direction.

[0023] A further improvement of the present invention is that the end ring is connected to the core shaft via a plurality of fasteners, and the fasteners are arranged in two rows and staggered.

[0024] A further improvement of the present invention is that the metal sealing element is made of a single metal of magnesium, aluminum, calcium, or an alloy material formed by combining at least two of these metals.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The metal packer described in the present invention has a sealing element made of a special metal or alloy material. The annulus is sealed by the principle that the volume of the metal or alloy increases after a hydration reaction. The design adopts an elastic envelope, segmented modular support and end deformable combined support mechanism to prevent disordered diffusion of the metal after swelling, thereby improving the pressure bearing capacity of the packer, so that the packer can meet the cementing and completion requirements of ultra-deep wells, geothermal wells, hot dry rocks and other ultra-high temperature oil and gas wells.

[0027] The metal packer described in the present invention adopts special metal alloy materials as the sealing element of the packer, which can solve the problems of insufficient temperature resistance and low long-term sealing reliability of conventional packers. At the same time, the packer is sealed by chemical reaction between the packer and the liquid in the well, without the need for mechanical and hydraulic sealing operations, saving corresponding mechanical parts, simple structure, easy operation, high sealing reliability, and relatively low requirements on wellbore shape, gap, etc.

[0028] The metal packer described in this invention features an elastic envelope and a deformable composite support mechanism, enabling automatic diameter change to prevent axial expansion of the sealing element, significantly improving the packer's setting effectiveness and sealing pressure resistance. This metal packer offers enhanced adaptability to on-site well conditions, meeting the annular isolation requirements of ultra-deep wells, geothermal wells, and ultra-high-temperature wells such as those in hot dry rock formations. It can also address reservoir stimulation needs such as slim-hole refracturing and high-pressure open-hole staged fracturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0030] Figure 1 Shown is a schematic structural diagram of a metal packer according to an embodiment of the present invention;

[0031] Figure 2 Shown is a schematic structural diagram of a metal sealing element according to an embodiment of the present invention;

[0032] Figure 3 FIG2 is a schematic diagram of the connection structure of a deformable combined support mechanism according to an embodiment of the present invention;

[0033] Figure 4 FIG2 is a schematic structural diagram of a deformable combined support mechanism according to an embodiment of the present invention, showing a side view;

[0034] Figure 5 FIG2 is a schematic structural diagram of a deformable combined support mechanism according to an embodiment of the present invention, showing a three-dimensional state;

[0035] Figure 6 FIG2 is a schematic structural diagram of a deformable combined support mechanism according to an embodiment of the present invention, showing the state after the deformable limiting ring is opened;

[0036] Figure 7 Shown is a schematic structural diagram of an end ring according to an embodiment of the present invention.

[0037] The drawings are not drawn to scale.

[0038] The meanings of the reference numerals in the accompanying drawings are as follows:

[0039] 1. Mandrel, 2. End ring, 3. Deformable combined support mechanism, 4. Elastic envelope, 5. Segmented support ring, 6. Middle metal sealing element, 7. End metal sealing element, 8. Fastener, 31. Protective sleeve, 32. Pressure ring, 33. First deformable limiting ring, 34. Second deformable limiting ring, 35. Fixed ring, 331. Fixed cylinder end, 332. Open groove, 333. Elastic rib. DETAILED DESCRIPTION

[0040] To make the technical solutions and advantages of the present invention more clearly understood, exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, and are not exhaustive. Furthermore, the embodiments and features of the embodiments of the present invention may be combined with each other unless there is a conflict.

[0041] Packers are commonly used tools in oil drilling and completion, used to isolate the annulus between the casing and the wellbore, or between the casing and the wellbore. Existing packer sealing elements are primarily made of rubber or special metals, achieving annular isolation through physical methods such as mechanical compression or hydraulic expansion.

[0042] However, since the packer achieves metal swelling through a chemical reaction, ensuring that the metal expands primarily radially, rather than axially, is crucial for achieving high-pressure isolation. Currently, an end ring (2) with fixed inner and outer diameters is primarily used to limit the initial axial displacement of the metal. To ensure good run-in performance, the outer diameters of the packer metal element and the end ring (2) must be smaller than the wellbore's inner diameter. However, relying solely on an end ring (2) with a fixed outer diameter cannot effectively prevent the reaction products from expanding axially, posing a risk of overflow and significantly impacting the packer's annular isolation effectiveness.

[0043] In order to solve the problems of insufficient temperature resistance and low wellbore adaptability of existing rubber packers, the present invention proposes a metal packer, whose sealing element is made of special metal or alloy material, and annular space isolation is achieved by the principle that the volume of the metal or alloy increases after hydration reaction.

[0044] Metal sealing elements are made of metals such as magnesium, aluminum, and calcium, or alloys formed by combining two or more of the above. These metals and alloys undergo a metal hydration reaction in a saltwater environment to form metal oxides or hydroxides. The volume of these products increases significantly compared to the original metal or alloy, allowing them to form a seal with any adjacent interface. For example, when magnesium reacts with water to form magnesium hydroxide, the volume expansion rate can reach 85%, while the volume expansion rate of aluminum reacting with water to form aluminum hydroxide can reach 160%. This can seal the gap in the casing annulus or the gap between the casing and the open hole. Hereinafter, the metal hydration reaction is referred to as metal swelling.

[0045] This embodiment adopts the design of elastic envelope 4, segmented modular support and end deformable combined support mechanism 3 to prevent disordered diffusion of metal after swelling, thereby improving the pressure bearing capacity of the packer, so that the packer can meet the cementing and completion requirements of ultra-deep wells, geothermal wells, hot dry rocks and other ultra-high temperature oil and gas wells.

[0046] In such Figure 1 In the embodiment shown, a metal packer comprises:

[0047] Mandrel 1, mandrel 1 is a circular tubular structure;

[0048] A metal sealing element is provided on the outside of the core shaft 1 , and the metal sealing element can undergo metal swelling with the downhole fluid, thereby expanding in volume and sealing the annulus between the core shaft 1 and the casing.

[0049] End rings 2 are provided at both ends of the metal sealing element. The end rings 2 are fixed on the core shaft 1 and can block the metal sealing element to prevent it from expanding along the axial direction of the core shaft 1 when expanding. Due to the provision of the end rings 2, the metal sealing element can only expand radially.

[0050] In the metal packer described in this embodiment, the metal sealing element is made of a metal such as magnesium, aluminum, or calcium, or an alloy material formed by combining two or more of these metals. These metals and alloys undergo a metal hydration reaction in a downhole brine environment to form metal oxides or hydroxides. These products significantly increase in volume compared to the original metal or alloy, resulting in volume expansion and the ability to form a seal with any adjacent interface.

[0051] In one embodiment, an end ring 2 with fixed inner and outer diameters is used to limit the axial displacement of the initial metal. To ensure that the packer has good lowering performance, the outer diameter of the metal sealing element and the end ring 2 must be smaller than the inner diameter of the wellbore. However, the end ring 2 with a fixed outer diameter alone cannot effectively ensure that the reaction product will not expand axially, and there is a risk of overflow of the expanded product, which greatly affects the annulus isolation effect of the packer.

[0052] Therefore, this embodiment adds an elastic envelope 4 and a deformable combined support mechanism 3 to solve the above problems.

[0053] In this embodiment, if Figure 2 As shown, an elastic envelope 4 is provided on the outside of the metal sealing element, and a deformable combined support mechanism 3 is provided at both ends of the metal sealing element; the elastic envelope 4 and the deformable combined support mechanism 3 are coated on the outside of the metal sealing element to form an expansion space.

[0054] During the expansion of the metal sealing element, the expansion space composed of the deformable combined support mechanism 3 and the elastic envelope 4 will expand together with the metal sealing element, covering the metal sealing element inside, ensuring that the metal will not dissolve and flow out after the hydration reaction occurs.

[0055] The deformable combined support mechanism 3 connects the two ends of the elastic envelope 4 , and the deformable combined support mechanism 3 is arranged on the inner side of the end ring 2 .

[0056] In one embodiment, the metal sealing element may be an integrated structure, and a cylindrical structure formed by the metal sealing element covers the outer side of the core shaft 1 .

[0057] Preferably, the metal sealing element comprises several segments, and several segmented support rings 5 are provided in the middle.

[0058] The segmented support can further support the metal sealing element and prevent it from diffusing along the axial direction of the core shaft 1. Cooperating with the end ring 2, it further ensures that the metal sealing element expands radially rather than axially during the expansion process.

[0059] The metal sealing element includes a middle metal sealing element 6 and an end metal sealing element 7. The middle metal sealing element 6 is a circular ring structure, and the end of the end metal sealing element 7 forms a concave-convex structure or a variable diameter structure that cooperates with the variable combination support mechanism.

[0060] In one embodiment, Figure 3 As shown, the deformable combined support mechanism 3 includes a pressure ring 32, and the pressure ring 32 includes a connecting portion in contact with the metal sealing element, and a fixing portion arranged on a side away from the metal sealing element.

[0061] The inner side surface of the fixing part contacts the core shaft 1 and has a relatively small thickness; a certain space is formed between the connecting part and the core shaft 1, and the metal sealing element is provided with a variable diameter structure, which is clamped in the space so that the connecting part is pressed on the metal sealing element, and the thickness of the connecting part is relatively thick.

[0062] In this embodiment, a transition portion between the connecting portion and the outer side of the fixing portion is provided with an inclined surface.

[0063] In a preferred embodiment, a protective sleeve 31 is provided on the outer side of the pressure ring 32 , and the protective sleeve 31 is a cylindrical structure.

[0064] The outer diameter of the connecting portion of the pressure ring 32 matches the inner diameter of the protective sleeve 31 .

[0065] In one embodiment, the deformable combined support mechanism 3 further includes a multi-layer deformable limiting ring, which is arranged on the outside of the pressure ring 32 , and in particular, the multi-layer deformable limiting ring is located on the outside of the fixed portion of the pressure ring 32 .

[0066] In the metal hydration reaction swelling seal according to this embodiment, the protective sleeve 31 is made of soluble material, which can dissolve in a salt water environment and lose strength, thereby allowing the multi-layer deformable limit ring and pressure ring 32 to expand radially, providing expansion space for the metal sealing element.

[0067] In this embodiment, the multi-layer deformable limiting ring deforms as the metal sealing element and the pressure ring 32 expand, forming a conical structure.

[0068] Preferably, the multi-layered variable diameter elastic ring comprises at least two layers of variable diameter elastic rings. Figure 4 、 Figure 5 In the illustrated embodiment, the multi-layer variable diameter elastic ring is a two-layer structure, including a first deformable limiting ring 33 and a second deformable limiting ring 34 .

[0069] The first deformable retaining ring 33 is located on the outside, and the second deformable retaining ring 34 is located on the inside. The first and second deformable retaining rings 33 and 34 have similar structures, both of which are annular structures. One end is connected to the core shaft 1 through the fixed cylinder end 331, and the other end covers the outside of the fixed part of the pressure ring 32.

[0070] The variable diameter elastic ring (including the first deformable limiting ring 33 and the second deformable limiting ring 34 ) includes a main body covering the outer side of the fixed portion of the pressure plate, and a fixed cylinder end 331 connected to the core shaft 1 .

[0071] The main body is provided with a plurality of opening grooves 332, which divide the main body into a plurality of elastic ribs 333. When the metal sealing element expands, the elastic ribs 333 will also deform to form a conical structure, so that the opening ends of the opening grooves 332 will open. In this embodiment, the opening grooves 332 of the variable diameter elastic rings of different layers are staggered, so that the whole body can maintain a sealed state after deformation without any gaps. For example, Figure 4 and Figure 5 As shown, the elastic rib 333 of the first deformable limiting ring 33 is arranged opposite to the opening groove 332 of the second deformable limiting ring 34 .

[0072] In the metal seal according to this embodiment, the inner and outer circles of the pressure ring 32 are designed with variable diameters, and the outer circle transitions from large diameter to small diameter through an inclined surface. The large diameter is the same as the inner diameter of the protective sleeve 31 and the same as the outer diameter of the outer deformable limit ring.

[0073] The inner major diameter of the connecting portion of the pressure ring 32 is the same as the outer minor diameter of the metal sealing element, and the outer minor diameter of the metal sealing element extends a certain distance into the inner major diameter of the pressure ring 32. Its inclined surface has the same angle as the inclined surface of the opening end of the multi-layer deformable retaining ring and contacts it, facilitating the deformation and expansion of the elastic rib 333.

[0074] The inner minor diameter of the pressure ring 32 and the inner sides of the fixed tube ends 331 of the first and second multi-layer deformable stop rings are all the same as and in contact with the outer diameter of the core shaft. The outer minor diameter of the pressure ring 32 is the same as and in contact with the inner diameter of the slotted end of the deformable stop ring.

[0075] In one embodiment, the end of the pressure ring 32 is fixed to the core shaft 1 through a fixing ring 35 .

[0076] In one embodiment, the end ring 2 is connected to the core shaft 1 via a plurality of fasteners 8, which are arranged in two rows and staggered. The fasteners 8 can be screws, bolts or other connecting parts.

[0077] Preferably, the metal sealing element is made of a single metal of magnesium, aluminum, calcium, or an alloy material formed by combining at least two of the metals.

[0078] In one embodiment, Figure 1 and Figure 7 As shown, end rings 2 are provided at both ends of the metal sealing element. The end rings 2 are fixedly provided and can block the axial expansion of the metal sealing element and enable the metal sealing element to expand radially.

[0079] In this embodiment, the metal sealing element is made of a metal such as magnesium, aluminum, calcium, or an alloy thereof. These metals or alloys undergo a metal hydration reaction in a saltwater environment to form metal oxides or hydroxides. The volume of these products is significantly increased compared to the original metal or alloy, thereby forming a seal with any adjacent interface.

[0080] The metal sealing element can be configured in any shape and can be segmented or integrated onto the core shaft. Both ends are limited by end rings 2, which are secured to the core shaft by fasteners 8. The deformable combined support mechanism 3, elastic envelope 4, and segmented support ring 5 provide expansion space and ensure radial expansion of the metal swelling product, preventing axial diffusion, thereby improving the pressure-bearing capacity of the packer.

[0081] An elastic envelope 4 is designed outside the metal sealing element to wrap the metal sealing element.

[0082] The contact point between the metal sealing element and the pressure ring 32 adopts a variable diameter design, and the local outer circle is slightly smaller, which can extend into the inner space on the left side of the pressure ring 32, thereby better fixing the swelling product of the metal sealing element and preventing it from diffusing axially.

[0083] The deformable combined support mechanism 3 comprises a plurality of layers of deformable limiting rings, a pressure ring 32, a fixing ring 35, a protective sleeve 31 and other components. The multi-layer deformable limiting ring is composed of two or more layers of deformable limiting rings, which are processed from elastic metal materials. In the initial state, the whole is cylindrical, one end is closed, and the other end is circumferentially designed with a plurality of slots, forming a plurality of deformable elastic ribs 333. The closed end partially extends slightly radially inward and contacts the core shaft. A certain bevel is designed on the inner side of the edge of the slotted section. When multiple deformable limiting rings are stacked and used, the slots of the elastic ribs 333 should be cross-spaced to prevent gaps.

[0084] The pressure ring 32 is made of a self-expanding rubber material, is sleeved on the core shaft, and is pressed on the metal sealing element to support and isolate the edge of the packer.

[0085] The multiple layers of deformable retaining rings are each sleeved over the compression ring 32. The inner sides of both the compression ring 32 and the deformable retaining rings contact the outer side of the core shaft. A retaining ring 35 is positioned in between to secure the metal sealing element in place after expansion of the compression ring 32 and the metal sealing element. Initially, a gap is created between the retaining ring 35, the compression ring 32, and the deformable retaining rings, providing axial clearance for the metal and compression ring 32 to swell. As the metal and compression ring 32 expand, the outer diameter of one end of the deformable retaining ring expands outward in a conical shape, providing radial clearance for both expansion.

[0086] The protective sleeve 31 is made of a soluble material and can dissolve in a saline environment and lose strength, thereby allowing the multi-layer deformable limiting ring and the pressure ring 32 to expand radially, providing expansion space for the metal sealing element.

[0087] Example 1

[0088] The metal sealing element is made of magnesium and aluminum alloy, which undergoes metal hydration reaction in a salt water environment to generate metal oxides or hydroxides, and its volume expands by 120%.

[0089] The metal sealing element can be divided into five sections and sleeved on the core shaft. The two ends are limited by end rings 2, and the end rings 2 are fixed to the core shaft by fasteners 8. Segmented support rings 5 are set between each section. The deformable combined support mechanism 3, elastic envelope 4 and segmented support rings 5 provide expansion space and ensure that the metal swelling product expands radially, preventing it from diffusing in the axial direction, thereby improving the pressure bearing capacity of the packer.

[0090] An elastic envelope 4 is designed outside the metal sealing element to wrap the metal sealing element.

[0091] The contact point between the metal sealing element and the pressure ring 32 adopts a variable diameter design, and the local outer circle is slightly smaller, which can extend into the inner space on the left side of the pressure ring 32, thereby better fixing the swelling product of the metal sealing element and preventing it from diffusing axially.

[0092] The deformable combined support mechanism 3 comprises two layers of deformable limiting rings, a pressure ring 32, a fixing ring 35, a protective sleeve 31 and other components. The multi-layer deformable limiting ring is composed of two layers of deformable limiting rings, namely a first deformable limiting ring 33 and a second deformable limiting ring 34. The deformable limiting ring is made of elastic metal material. In the initial state, the whole is cylindrical, one end is closed, and the other end is circumferentially designed with several grooves, forming several deformable elastic ribs 333. The closed end partially extends slightly radially inward and contacts the core shaft. A certain bevel is designed on the inner side of the edge of the slotted section. The slots of the elastic ribs 333 of the two deformable limiting rings should be cross-spaced to prevent gaps.

[0093] The pressure ring 32 is made of a self-expanding rubber material, is sleeved on the core shaft, and is pressed on the metal sealing element to support and isolate the edge of the packer.

[0094] The multiple layers of deformable retaining rings are each sleeved over the compression ring 32. The inner sides of both the compression ring 32 and the deformable retaining rings contact the outer side of the core shaft. A retaining ring 35 is positioned in between to secure the metal sealing element in place after expansion of the compression ring 32 and the metal sealing element. Initially, a gap is created between the retaining ring 35, the compression ring 32, and the deformable retaining rings, providing axial clearance for the metal and compression ring 32 to swell. As the metal and compression ring 32 expand, the outer diameter of one end of the deformable retaining ring expands outward in a conical shape, providing radial clearance for both expansion.

[0095] The protective sleeve 31 is made of a soluble material and can dissolve in a saline environment and lose strength, thereby allowing the multi-layer deformable limiting ring and the pressure ring 32 to expand radially, providing expansion space for the metal sealing element.

[0096] Example 2

[0097] The metal sealing element is made of a metal alloy of magnesium, aluminum and calcium. In a salt water environment, a metal hydration reaction occurs to generate metal oxides or hydroxides, and the volume expands by 130%.

[0098] The metal sealing element is a monolithic structure, with both ends limited by end rings 2, which are secured to the core shaft by fasteners 8. The deformable composite support mechanism 3, elastic envelope 4, and segmented support ring 5 provide expansion space and ensure radial expansion of the metal swelling product, preventing axial diffusion, thereby improving the pressure-bearing capacity of the packer.

[0099] An elastic envelope 4 is designed outside the metal sealing element to wrap the metal sealing element.

[0100] The contact point between the metal sealing element and the pressure ring 32 adopts a variable diameter design, and the local outer circle is slightly smaller, which can extend into the inner space on the left side of the pressure ring 32, thereby better fixing the swelling product of the metal sealing element and preventing it from diffusing axially.

[0101] The deformable combined support mechanism 3 comprises two layers of deformable limiting rings, a pressure ring 32, a fixing ring 35, a protective sleeve 31 and other components. The multi-layer deformable limiting ring is composed of two layers of deformable limiting rings, namely a first deformable limiting ring 33 and a second deformable limiting ring 34. The deformable limiting ring is made of elastic metal material. In the initial state, the whole is cylindrical, one end is closed, and the other end is circumferentially designed with several grooves, forming several deformable elastic ribs 333. The closed end partially extends slightly radially inward and contacts the core shaft. A certain bevel is designed on the inner side of the edge of the slotted section. The slots of the elastic ribs 333 of the two deformable limiting rings should be cross-spaced to prevent gaps.

[0102] The pressure ring 32 is made of a self-expanding rubber material, is sleeved on the core shaft, and is pressed on the metal sealing element to support and isolate the edge of the packer.

[0103] The multiple layers of deformable retaining rings are each sleeved over the compression ring 32. The inner sides of both the compression ring 32 and the deformable retaining rings contact the outer side of the core shaft. A retaining ring 35 is positioned in between to secure the metal sealing element in place after expansion of the compression ring 32 and the metal sealing element. Initially, a gap is created between the retaining ring 35, the compression ring 32, and the deformable retaining rings, providing axial clearance for the metal and compression ring 32 to swell. As the metal and compression ring 32 expand, the outer diameter of one end of the deformable retaining ring expands outward in a conical shape, providing radial clearance for both expansion.

[0104] The protective sleeve 31 is made of a soluble material and can dissolve in a saline environment and lose strength, thereby allowing the multi-layer deformable limiting ring and the pressure ring 32 to expand radially, providing expansion space for the metal sealing element.

[0105] The metal packer described in the present invention has a sealing element made of a special metal or alloy material, and realizes annular space isolation through the principle that the volume of the metal or alloy increases after a hydration reaction. It adopts an elastic envelope 4, a segmented modular support and an end deformable combined support mechanism 3 design to prevent disordered diffusion of the metal after swelling, thereby improving the pressure bearing capacity of the packer, so that the packer can meet the cementing and completion requirements of ultra-high temperature oil and gas wells such as ultra-deep wells, geothermal wells and hot dry rocks.

[0106] The metal packer described in the present invention adopts special metal alloy materials as the sealing element of the packer, which can solve the problems of insufficient temperature resistance and low long-term sealing reliability of conventional packers. At the same time, the packer is sealed by chemical reaction between the packer and the liquid in the well, without the need for mechanical and hydraulic sealing operations, saving corresponding mechanical parts, simple structure, easy operation, high sealing reliability, and relatively low requirements on wellbore shape, gap, etc.

[0107] The metal packer of the present invention is equipped with an elastic envelope 4 and a deformable combined support mechanism 3. This allows for automatic diameter change, thereby preventing axial expansion of the sealing element and significantly improving the packer's setting effectiveness and sealing pressure-bearing capacity. This metal packer offers improved adaptability to on-site well conditions and can meet the annular isolation requirements of ultra-deep wells, geothermal wells, and ultra-high-temperature wells such as those in hot dry rock formations. It can also address reservoir transformation needs such as slim-hole refracturing and high-pressure open-hole staged fracturing.

[0108] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent substitutions of these features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0109] In the description of the present invention, unless otherwise specified, "plurality" means two or more; terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0110] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0111] Certain terms are used throughout this specification to refer to specific system components. As those skilled in the art will appreciate, different names can often be used to refer to the same component, and thus this specification does not intend to distinguish between components that differ only in name, not function. References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "an embodiment" appearing in various places throughout this specification do not necessarily refer to the same embodiment.

[0112] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

[0113] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and / or modifications that fall within the scope of the present invention, and changes and / or modifications made in accordance with the embodiments of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A metal packer, characterized in that: include: Mandrel (1); A metal sealing element is arranged outside the core shaft (1), and the metal sealing element can undergo metal swelling with downhole fluid, thereby isolating the annulus between the core shaft (1) and the casing; as well as The outer side of the metal sealing element is provided with an elastic envelope (4), and both ends of the metal sealing element are provided with a deformable combined support mechanism (3); the elastic envelope (4) and the deformable combined support mechanism (3) are wrapped around the outside of the metal sealing element to form an expansion space.

2. The metal packer according to claim 1, characterized in that: The metal sealing element is a cylindrical one-piece structure.

3. The metal packer according to claim 2, characterized in that: The metal sealing element comprises several sections, and a plurality of segmented support rings (5) are arranged in the middle.

4. The metal packer according to claim 2 or 3, characterized in that: The deformable combined support mechanism (3) comprises a pressure ring (32), wherein the pressure ring (32) comprises a connecting portion in contact with the metal sealing element and a fixing portion arranged on a side away from the metal sealing element; The connecting portion is relatively thick and forms an annular space with the core shaft (1), and the metal sealing element is pressed in the space; the fixing portion is relatively thin.

5. The metal packer according to claim 4, characterized in that: A protective sleeve (31) is provided on the outer side of the pressure ring (32).

6. The metal packer according to claim 5, characterized in that: The deformable combined support mechanism (3) further comprises multiple layers of deformable limiting rings.

7. The metal packer according to claim 6, characterized in that: The protective sleeve (31) is made of a soluble material and can dissolve in a saline environment and lose strength, thereby allowing the multi-layer deformable limiting ring and the pressure ring (32) to expand radially, providing expansion space for the metal sealing element.

8. The metal packer according to claim 7, characterized in that: The multi-layered variable diameter elastic ring comprises at least two layers of variable diameter elastic rings; The variable diameter elastic ring comprises a main body covering the outer side of the fixed portion of the pressure plate, and a fixed cylinder end (331) connected to the core shaft (1); The main body is provided with a plurality of opening grooves (332), which divide the main body into a plurality of elastic ribs (333); the opening grooves (332) of the variable diameter elastic rings in different layers are staggered.

9. The metal packer according to any one of claims 4 to 8, characterized in that: The end of the pressure ring (32) is fixed on the core shaft (1) through a fixing ring (35).

10. The metal packer according to any one of claims 1 to 9, characterized in that: End rings (2) are provided at both ends of the metal sealing element, and the end rings (2) are fixed on the core shaft (1) and are capable of blocking the metal sealing element; The end ring (2) prevents the metal sealing element from expanding in the axial direction of the core shaft (1) when the metal sealing element expands, while ensuring that the metal sealing element expands in the radial direction.

11. The metal packer according to claim 10, characterized in that: The end ring (2) is connected to the core shaft (1) via a plurality of fasteners (8), and the fasteners (8) are arranged in two rows and staggered.

12. The metal packer according to any one of claims 1 to 11, characterized in that: The metal sealing element is made of a single metal of magnesium, aluminum, calcium, or an alloy material formed by combining at least two of the metals.

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