Fluid seal for downhole acoustic measurement tools

Abstract

A fluid seal assembly has a sleeve disposed circumferentially about a downhole tool. First and second fasteners extend circumferentially around the sleeve proximate the first and second ends of the sleeve, respectively. The first fastener and the second fastener may include a shape memory alloy that, in response to a temporarily elevated temperature, causes the first fastener and the second fastener to circumferentially press the sleeve against an outer surface of the downhole tool.

Description

Technical Field

[0001] The present invention relates to fluid seals, and in particular to fluid seals for downhole acoustic wave measurement tools. Background Art

[0002] Downhole acoustic measurement (or imaging) tools are used for oil and gas exploration and production in both cased and uncased wellbores. For example, when used in a cased wellbore, such acoustic imaging may be performed to inspect the casing and the cement that holds the casing in the wellbore. When used in an uncased wellbore, acoustic imaging may be performed to obtain an image of the wellbore surface, such as identifying vugs, fractures, textures, and acoustic properties of the subsurface formations penetrated by the wellbore.

[0003] The downhole acoustic tool includes one or more acoustic sensors disposed near the outer perimeter of the tool. A cover in front of the sensors protects the interior of the tool from the wellbore fluid. Summary of the invention

[0004] This Summary is provided to introduce some concepts that will be further described in the Detailed Description below. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to help limit the scope of the claimed subject matter.

[0005] In one or more embodiments, the apparatus may include a downhole tool. The downhole tool may include an acoustic sensor operable to transmit and receive acoustic signals to perform downhole measurements and a fluid seal assembly. The fluid seal assembly may include a sleeve disposed circumferentially around the downhole tool. The sleeve may be sufficiently acoustically transparent to pass the transmitted and received acoustic signals. The first fastener and the second fastener may extend circumferentially around the sleeve near the first end and the second end of the sleeve, respectively.

[0006] In another embodiment, the device may include a downhole tool. The downhole tool may include an acoustic sensor operable to transmit and receive acoustic signals to perform downhole measurements and a fluid seal assembly. The fluid seal assembly may include a sleeve disposed circumferentially around the downhole tool. The sleeve may be sufficiently acoustically transparent to pass the transmitted and received acoustic signals. A first fastener may be disposed circumferentially around the downhole tool. The first fastener may have a first internal thread engaged with a first external thread of the downhole tool; thereby, the first end of the sleeve is pressed against the first surface of the downhole tool. A second fastener may be disposed circumferentially around the downhole tool. The second fastener may have a second internal thread engaged with a second external thread of the downhole tool; thereby, the second end of the sleeve is pressed against the second surface of the downhole tool.

[0007] In another embodiment, the device may include a downhole tool. The downhole tool may include an acoustic sensor that is operable to transmit and receive acoustic signals to perform downhole measurements when the downhole tool is conveyed in the wellbore. The housing, which may include a plurality of interconnected housing portions, may collectively define at least a portion of an internal chamber containing the sensor. Adjacent housing portions define gaps that collectively form a fluid passage between an outer surface of the housing and the internal chamber. At least one gap may terminate in a slot extending along the outer surface. A sleeve may be disposed circumferentially around the housing; thereby, when the downhole tool is conveyed in the wellbore, the wellbore fluid is inhibited from flowing into the internal chamber via the gap. A material may be disposed within the sleeve and further inhibit the wellbore fluid from entering the slot.

[0008] These and additional aspects of the present disclosure are set forth in the following description, and / or may be learned by one of ordinary skill in the art by reading the materials herein and / or practicing the principles described herein.At least some aspects of the present disclosure may be implemented by the devices recited in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present disclosure can be understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0010] Figure 1 is a schematic diagram of at least a portion of an example implementation of an apparatus according to one or more aspects of the present disclosure.

[0011] Figure 2-4 is a schematic diagram of at least a portion of an example implementation of an apparatus at various stages of an assembly operation according to one or more aspects of the present disclosure.

[0012] Figure 5-7 is a schematic diagram of at least a portion of another example embodiment of an apparatus at various stages of assembly operations according to one or more aspects of the present disclosure.

[0013] Figure 8 is a schematic diagram of at least a portion of an example implementation of an apparatus according to one or more aspects of the present disclosure.

[0014] Fig. 9 is a schematic diagram of at least a portion of an example implementation of an apparatus according to one or more aspects of the present disclosure.

[0015] Figure 10-12 is a method of performing an assembly according to one or more aspects of the present disclosure at different stages of an assembly operation. Figure 8 and 9 A side cross-sectional view of a portion of the device shown in FIG.

[0016] Figure 13-24 According to one or more aspects of the present disclosure Figure 8 and 9 00146] A side cross-sectional view of a portion of an example embodiment of the device shown in FIG.

[0017] Fig.25 is a schematic diagram of at least a portion of an example implementation of an apparatus according to one or more aspects of the present disclosure.

[0018] Figure 26-30 According to one or more aspects of the present disclosure Fig.25 A side cross-sectional view of a portion of an example embodiment of the device is shown.

[0019] Figure 31-36 is a side cross-sectional view of a portion of an example implementation of an apparatus according to one or more aspects of the present disclosure. DETAILED DESCRIPTION

[0020] It should be understood that the following disclosure provides many different embodiments or examples for realizing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and / or letters in various examples. This repetition is for simplicity and clarity and does not itself specify the relationship between the various embodiments and / or configurations discussed. In addition, in the following description, the description of a first feature in contact with a second feature may include an embodiment in which the first and second features are in direct contact, and may also include an embodiment in which additional features may be inserted into the first and second features so that the first and second features may not be in direct contact.

[0021] Figure 1 1 is a schematic diagram of at least a portion of an example embodiment of a wellsite system 100 to which one or more aspects of the present disclosure may be applied. The wellsite system 100 may be onshore (as shown) or offshore. Figure 1 In the illustrated exemplary wellsite system 100, a tool string 104 is conveyed in a wellbore (or borehole) 108 via a wireline, slickline, and / or other conveying device 112. The exemplary wellsite system 100 may be used to evaluate the wellbore 108, cement 116 securing a casing 120 within the wellbore 108, tubulars (not shown) secured in the casing 120 (e.g., production service pipe), and / or a subterranean formation 124 penetrated by the wellbore 108 in a cased section 150 and / or an open hole section 155. Although a large portion of the wellbore 108 is in the Figure 11 is depicted as being cased, but a large portion of the wellbore may be uncased (“open,” without casing 120 and cement 116).

[0022] The tool string 104 is suspended in the wellbore 108 from the lower end of a conveying device 112. The conveying device 112 may be a single-conductor or multi-conductor slide-wire or wireline logging cable wound on a drum 113 of a winch 115 located at the surface 128 of a wellsite from which the wellbore 108 extends. The wellsite surface 128 is a generally flat terrain surface (i.e., the surface of the earth), the floor of a drilling rig (not shown) or other equipment at the wellsite, which is vertically penetrated by the wellbore 108. Operation of the winch 115 rotates the drum 113 to reel in the conveying device 112, thereby pulling the tool string 104 in the wellbore 108 in an uphole direction 101, and to pay out the conveying device 112, thereby moving the tool string 104 in the wellbore 108 in a downhole direction 102. The transport device 112 may include at least one or more conductors (not shown) that facilitate data communication between the tool string 104 and surface equipment 132 disposed at the well site surface 128, including through one or more slip rings, cables, and / or other conductors (in Figure 1 The conveyor 112 may be a cable (schematically shown by reference numeral 133) that electrically connects one or more conductors of the conveyor 112 to the surface equipment 132. The conveyor 112 may alternatively convey the tool string 104 without conductors in the cable but with at least one module that can autonomously acquire and / or process downhole measurements and / or store downhole measurements in a downhole memory without human intervention or communication with the surface equipment 132.

[0023] The tool string 104 includes a plurality of modules (or "tools") 136, one or more of which may include an elongated housing, a mandrel, a chassis, and / or other structure that carries various electronic and / or mechanical components. For example, at least one module 136 may be or include at least a portion of an apparatus for measuring characteristics and / or properties of the wellbore 108, the casing 120, tubulars (not shown) installed in the casing 120, the cement 116, and / or the formation 124, and / or an apparatus for obtaining sidewall or in-line core and / or fluid (liquid and / or gas) samples from the wellbore 108 and / or the formation 124. Figure 1 While the exemplary embodiment is shown, other embodiments of the downhole tool string 104 within the scope of the present disclosure may include more or fewer components or modules 136 .

[0024] The wellsite system 100 also includes a data processing system, which may include at least a portion of one or more surface equipment 132, control equipment and / or other electrical and / or mechanical equipment in one or more modules 136 of the tool string 104 (e.g., a downhole controller 140), a remote computer system (not shown), communication equipment, and / or other equipment. The data processing system may include one or more computer systems or devices, and / or may be a distributed computer system. For example, the collected data or information may be stored, distributed, transmitted to wellsite operators, and / or processed locally (downhole or on the surface) and / or remotely.

[0025] The data processing system may perform the methods and / or processes described below, or portions thereof, alone or in combination with other system components. For example, according to one or more aspects of the present disclosure, the data processing system may include processor capabilities for collecting caliper, acoustic (e.g., ultrasonic) and / or other data related to the evaluation of cement 116, casing 120, tubulars (not shown) installed in casing 120, and / or formation 124. The methods and / or processes within the scope of the present disclosure may be implemented by one or more computer programs running in a processor, such as in one or more modules 136 of the tool string 104 and / or surface equipment 132. Such programs may utilize data received from the downhole controller 140 and / or other modules 136, and may transmit control signals to operating elements of the tool string 104, wherein such communication may be via one or more electrical conductors or optical conductors of the conveying device 112. The program may be stored on a tangible, non-transitory, computer-usable storage medium associated with one or more processors of the downhole controller 140, other modules 136 of the tool string 104, and / or the surface equipment 132, or may be stored on an external, tangible, non-transitory, computer-usable storage medium electrically coupled to such processors. The storage medium may be one or more known or future developed storage media, such as a magnetic disk, an optically readable disk, a flash memory, or another computer-readable device, including a remote storage device coupled via one or more wired and / or wireless communication links, etc.

[0026] like Figure 1 As shown in the figure 138, at least one module 136 can be or include a downhole acoustic (e.g., ultrasonic) measurement tool, which is operable to obtain acoustic measurements characterizing the wellbore 108, the casing 120, the tubular (not shown) installed in the casing 120, the cement 116, and / or the formation 124. The downhole acoustic measurement tool 138 includes one or more acoustic transducers 139 (e.g., a single transducer or a phased array transducer, etc.), each of which can operate as an acoustic transmitter and / or receiver. Example implementations of the downhole acoustic measurement tool 138 within the scope of the present disclosure are described below.

[0027] like Figure 1 As shown in the figure at 142, another (or more) of the modules 136 may be or include an orientation module that allows measuring the orientation of the downhole acoustic measurement tool 138. Such a module 142 may include, for example, one or more relative bearing (RB) sensors, gravity / acceleration sensors, magnetometers, and gyroscope sensors.

[0028] like Figure 1 As shown in the figure at 146, another (or more) of the modules 136 can be or include a centralizer module. For example, the centralizer module 146 can include an electric motor driven by a controller (not shown) and / or other device for actively extending ("opening") and retracting ("closing") the plurality of centering arms 147. Although in Figure 1 Only two centering arms 147 are depicted in the exemplary embodiment shown, but other embodiments within the scope of the present disclosure may have more than two centering arms 147. Extension of the centering arms 147 helps push the downhole acoustic measurement tool 138 to a central location within the casing 120, another tubular, or the wellbore 108 being investigated by the downhole acoustic measurement tool 138. Embodiments of tool strings within the scope of the present disclosure may include more than one instance of the downhole acoustic measurement tool 138 and / or more than one instance of the centralizer module 146. The module 136 may be delivered in either or both of the open hole section 150 and the lower cased section 155, including embodiments in which the centralizer module 146 and the phased array module 138 may be configured or configurable for use in either or both of these sections. The tool string 104 may also not include the centralizer module 146, or may include another type of centralizer module, such as a passive centralizer module.

[0029] Figure 2-30 Portions of example downhole tools 301, 302, 401-406, 408-422 are depicted, each of which may be Figure 1 The example implementation of the downhole acoustic measurement tool 138 shown may include one or more features and / or operating modes. Each downhole tool 301, 302, 401-406, 408-422 includes an acoustic sensor 311 (e.g., Figure 1The sensor segment 310 of the downhole tool 301 (one or more instances of the acoustic sensor 139 in the embodiment) is operable to transmit an acoustic excitation signal and / or receive an echo signal to perform downhole measurements. The sensor segment 310 can be located between the housing portions 312, 314 of each downhole tool 301, 302, 401-406, 408-422. Each downhole tool 301, 302, 401-406, 408-422 also includes an outer sleeve 318, 458, 460, 466, 475, 477, 479 that surrounds the sensor segment 310 and the adjacent ends of the housing portions 312, 314 and is configured to inhibit the flow of wellbore fluid into the sensor segment 310.

[0030] Figure 2-4 314 . is a schematic side view of a downhole tool 301 during various stages of an assembly operation according to one or more aspects of the present disclosure. The tapered member 316 can be temporarily connected to the housing portion 312 to facilitate placement of the outer sleeve 318 around the sensor segment 310 and adjacent portions of the housing portions 312 , 314 . That is, positioning the outer sleeve 318 on the tapered member 316 radially expands (or stretches) the outer sleeve 318 so that the outer sleeve 318 can then be pulled over the sensor segment 310 , including overlapping the proximal ends of the housing portions 312 , 314 . Lubrication can be used to reduce friction between the outer sleeve 318 and the tapered member 316 , the sensor segment 310 , and the housing portions 312 , 314 . The tapered member 316 can then be disconnected from the housing portion 312 .

[0031] The outer sleeve 318 can be or include a thin-walled cylindrical elastomer, which can be less than 1 mm thick, but can also be thicker, as long as it remains sufficiently acoustically transparent to the sensor signal. Acoustic transparency can also be obtained by using a cylindrical wall thickness corresponding to a portion (e.g., ¼, ½, ¾ or other portion) of the wavelength of the acoustic signal in the material of the outer sleeve 318. The outer sleeve 318 can be formed by molding a rubber compound into a desired shape. Example materials for the outer sleeve 318 include hydrogenated nitrile rubber (HNBR), fluoroelastomer (FKM), and perfluoroelastomer (FFKM), etc. The inner radius of the outer sleeve 318 can be slightly smaller than the outer diameter of the housing portions 312, 314 and / or the sensor segment 310, so that the outer sleeve constantly exerts a radially inward force on the sensor segment 310 and the housing portions 312, 314.

[0032] Figure 5-7314 and the sensor segment 310. The outer sleeve 318 is a schematic side view of a downhole tool 302 during different stages of an assembly operation according to one or more aspects of the present disclosure. Instead of using a tapered member 316 to facilitate placement of an outer sleeve 318 around housing portions 312, 314 and sensor segment 310, the tapered member 316 can be used to facilitate placement of the outer sleeve 318 onto a rigid tubular member 320, which can maintain the outer sleeve 318 in a radially expanded (or stretched) state. The inner diameter of the rigid tubular member 320 is greater than the outer diameter of the housing portions 312, 314 and the sensor segment 310. The rigid tubular member 320 with the outer sleeve 318 can be placed around the sensor segment 310, and then the outer sleeve 318 can be withdrawn from the rigid tubular member 320 onto the sensor segment 310. The outer sleeve 318 can then be radially contracted (or retracted) and contact the adjacent ends of the sensor segment 310 and the housing portions 312, 314. Lubrication may be used to reduce friction between the outer sleeve 318 and the tapered member 316, the rigid tubular member 320, the sensor segment 310, and the housing portions 312, 314. The rigid tubular member 320 may allow the outer sleeve 318 to be mounted on a sensor segment 310 having an outer diameter that is smaller, similar, or larger than the adjacent housing portions 312, 314.

[0033] As described above, the outer sleeve 318 may be formed of an elastomer that may allow the outer sleeve 318 to expand (or stretch) radially to fit around the sensor segment 310. Other outer sleeves within the scope of the present disclosure may alternatively include a material (e.g., a polymer) that deforms (i.e., contracts or shrinks radially) when the temperature increases, thereby causing the circumference of the outer sleeve to decrease in a radially inward direction, such that the outer sleeve is pressed against the outer surface of the sensor segment 310 and the adjacent ends of the housing portions 312, 314.

[0034] For example, fluorinated ethylene propylene (FEP), shape memory alloys (SMA), and other heat shrink materials can be used to form the outer sleeve. Rigid materials, such as metals, bulk metallic glass (BMG), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), and other hard polymers can also be used to form the outer sleeve. Figure 8-30, each of the downhole tools 401-406, 408-422 includes an outer sleeve 319, 458, 460, 466, 475, 477, 479, which may be formed of an elastomer (e.g., as described above for outer sleeve 318), a heat shrink material, or a rigid material. However, in each case, the material forming the outer sleeve 319, 458, 460, 466, 475, 477, 479 is sufficiently acoustically transparent to pass acoustic signals emitted and received by the sensor 311. Such an outer sleeve, or at least the portion of the outer sleeve in front of the acoustic sensor, also has a sufficiently uniform thickness to allow a well-regulated acoustic signal and avoid disruptive spectral components.

[0035] The outer sleeve including the heat shrink material may not be stretched in the radially outward direction initially because its initial inner diameter may be larger than the maximum diameters of the sensor segment 310 and the housing portions 312, 314. After the outer sleeve is disposed around the adjacent ends of the sensor segment 310 and the housing portions 312, 314, the outer sleeve is heated to cause the outer sleeve to decrease in the radially inward direction such that the outer sleeve is pressed against the outer surfaces of the sensor segment 310 and the housing portions 312, 314.

[0036] In order to improve the sealing performance of each of the outer sleeves, the outer sleeves may be clamped onto the outer surfaces of the housing portions 312, 314 adjacent to the sensor segment 310. For example, Figure 8 4 is a schematic side view of a downhole tool 401 including radial fasteners 452 that clamp the outer sleeve 319 to the outer surfaces of the housing portions 312, 314. Similarly, Fig. 9 is a schematic side view of a downhole tool 402 including radial fasteners 454 that clamp the outer sleeve 319 to the outer surfaces of the housing portions 312 , 314 .

[0037] Each fastener 452, 454 may have an annular structure. Figure 8 As shown, the annular fastener 452 can have a circular or otherwise elliptical cross-sectional shape. Fig. 9As shown, the annular fastener 454 may have a square or otherwise rectangular cross-sectional shape. The fasteners 452, 454 may be formed of SMA such that temporarily or permanently raising the temperature of the fasteners 452, 454 from ambient to elevated temperatures (e.g., by heat guns, oven baking, and / or other means) for some SMA alloys, or raising the temperature from subambient or sub-zero temperatures to ambient or slightly elevated temperatures (e.g., by rapid installation after removal from liquid nitrogen storage, and / or other means) for other types of SMA alloys, deforms the fasteners 452, 454 (i.e., changes their crystal arrangement) such that the circumference / radius of each fastener 452, 454 is reduced, thereby applying a radially inward force to press the outer sleeve 319 against the outer surfaces of the housing portions 312, 314. Although the downhole acoustic measurement tools 401 , 402 are shown as including one fastener 452 , 454 that clamps each end of the outer sleeve 319 , two or more fasteners 452 , 454 may be used to clamp each end of the outer sleeve 319 .

[0038] Pressing the outer sleeve 319 against the housing portions 312, 314 forms (or facilitates) a fluid seal between the outer sleeve 319 and the housing portions 312, 314. Thus, the outer sleeve 319 and fasteners 452, 454 may collectively form a fluid seal assembly for each downhole tool 401, 402.

[0039] Figure 10-12 is a schematic cross-sectional view of a downhole tool 403 during various stages of an assembly operation according to one or more aspects of the present disclosure. The downhole acoustic measurement tool 403 may be Figure 8 and 9 402 and include one or more features and / or operating modes of the one or more downhole tools 401, 402, including those indicated by common reference numerals. For example, downhole tool 403 may include fastener 456, which has one or more features and / or operating modes of fasteners 452, 454.

[0040] The temperature of the fastener 456 may be increased in multiple steps to press the outer sleeve 319 against the outer surfaces of the housing portions 312, 314. For example, the fastener 456 may first be positioned along the downhole tool 403 and the outer sleeve 319 at a desired axial position, such as Fig.10 Thereafter, the fastener 456 may be heated to an initial temperature so that the fastener 456 applies a relatively small radially inward force to the outer sleeve 319, thereby presetting the fastener 456 in a desired axial position, such as Fig.11Then, the fastener 456 can be heated to a second (i.e., higher) temperature so that the fastener 456 applies an increased radially inward force to the outer sleeve 319 to further press the outer sleeve 319 against the outer surfaces of the housing portions 312, 314, thereby physically clamping the outer sleeve 319 in place and increasing the fluid seal between the outer sleeve 319 and the outer surfaces of the housing portions 312, 314, as shown. Fig.12 shown.

[0041] Figure 13-23 Schematic cross-sectional views of portions of downhole tools 404-406, 408-416, respectively, each of which may be Figure 8-12 Exemplary embodiments of one or more downhole tools 401 - 403 are shown and include one or more features and / or modes of operation of the one or more downhole tools 401 - 403 , including where indicated by common reference numerals.

[0042] like Fig.13 As shown, the outer sleeve 458 of the downhole tool 404 may include a sleeve extending in a radially outward direction and located at the fastener 452 (from Figure 8 ) and the thicker section 459 between the outer surfaces of the shell portions 312, 314. Fig.14 As shown, the outer sleeve 458 of the downhole tool 405 may also include a fastener 454 (from Fig. 9 ) and the thicker section 459 between the outer surface of the housing parts 312, 314. When the fasteners 452, 454 press the outer sleeve 458 against the outer surface of the housing parts 312, 314, Fig.13 and 14 The thicker section 459 of the outer sleeve 458 shown may prevent or inhibit the fasteners 452 , 454 from piercing the outer sleeve 458 .

[0043] like Fig.15 As shown, the outer sleeve 460 of the downhole tool 406 may include circumferential profiles 461, 462 for fastening the fastener 452 (from Figure 8 ) is maintained in a predetermined axial position. The downhole tool 406 may include a plurality of fasteners 452 on each end of the outer sleeve 460 to improve the fluid seal between the outer sleeve 460 and the outer surface of the housing portions 312, 314.

[0044] The circumferential profiles 461, 462 may include circumferential grooves 461 facing in a radially outward direction for receiving the fastener 452 and retaining the fastener 452 in a predetermined axial position along the outer sleeve 460. The circumferential profiles 461, 462 may also or alternatively include circumferential ridges 462 extending in a radially outward direction for receiving the fastener 452 therebetween (i.e., on opposite sides of the fastener 452) and for retaining the fastener 452 in a predetermined axial position along the outer sleeve 460.

[0045] The outer sleeve 460 may also or alternatively have a plurality of thicker sections 463, each of which extends in a radially inward direction and is located between the fastener 452 and the outer surface of the housing portion 312, 314. When the fastener 452 presses the outer sleeve 460 against the outer surface of the housing portion 312, 314, the thicker sections 463 may prevent or inhibit the fastener 452 from piercing the outer sleeve 460. In addition, when the thicker sections 463 below the fastener 452 are radially compressed, they form an axial seal along the interface between the sleeve 460 and the housing portion 312, 314 in a manner that may be more effective than the fastener 452. Fig.13 and 14 The uniformly thicker section 459 shown is more effective and reliable.

[0046] Thicker sections 463 of outer sleeve 460 may each be disposed within a respective circumferential groove (or channel) 469 extending along the outer surfaces of housing portions 312, 314. Thicker sections 463 and circumferential grooves 469 may collectively facilitate positioning of outer sleeve 460 about a desired axial position of sensor segment 310.

[0047] like Fig.16 As shown, the thicker sections 467 of the outer sleeve 466 of the downhole tool 408 can each be disposed within a corresponding circumferential groove (or channel) 469 extending along the outer surface of the housing portions 312, 314. The thicker sections 467 and the circumferential grooves 469 can collectively facilitate positioning of the outer sleeve 466 around the desired axial position of the sensor segment 310.

[0048] although Fig.15 and 16 The thicker sections 463, 467 in the embodiment are depicted as having a substantially circular cross-sectional shape, but other cross-sectional shapes are also within the scope of the present disclosure. For example, the cross-sectional shape of the thicker sections 463, 467 can be a triangle, a rectangle and / or other geometric shapes.

[0049] like Fig.17As shown, the outer surfaces of the housing portions 312, 314 of the downhole tool 409 may each include a circumferential channel (or groove) 472 containing a gasket 471. Each gasket 471 may have an X-shaped cross-sectional profile, such as an X-shaped ring known in the art. When the fastener 452 presses the outer sleeve 319 against the gasket 471, a fluid seal may be formed between the outer sleeve 319 and the gasket 471.

[0050] Downhole environments may contain highly corrosive hydrogen-based fluids and gases that attack metal fasteners and may cause failure of the materials forming such fasteners. According to one or more aspects of the present disclosure, to delay and / or prevent such corrosion, the fasteners may be protected from the external environment by isolating (e.g., covering) the fasteners from the external space and the external sleeve fluid. This may be achieved in different ways.

[0051] like Fig.18 As shown, the fastener 452 of the downhole tool 410 can be rolled into the end 473 of the outer sleeve 319 so that one end 473 of the outer sleeve 319 is wrapped around one of the fasteners 452, and the opposite end 473 of the outer sleeve 319 is wrapped around the other of the fasteners 452, thereby isolating the fastener 452 from the external space fluid. The outer surface of the housing parts 312, 314 can have Fig.17 The channels 472 each contain a gasket 474. When the fastener 452 presses the outer sleeve 319 against the gasket 474, a fluid seal can be formed between the outer sleeve 319 and each gasket 474. The gasket 474 can also have a non-circular cross-sectional shape, such as a square or other rectangular shape, or Fig.17 X-ring 471 is shown.

[0052] like Fig.19 As shown, each end of the outer sleeve 475 of the downhole tool 411 may have an internal circumferential groove (or receiver) 476, which contains a corresponding one of the fasteners 452, thereby isolating the fasteners 452 from the external space fluid. The outer surface of the housing parts 312, 314 may have Fig.17 The channels 472 each contain a gasket 474. When the fastener 452 presses the outer sleeve 319 against the gasket 474, a fluid seal can be formed between the outer sleeve 319 and each gasket 474. The gasket 474 can also have a non-circular cross-sectional shape, such as a square or other rectangular shape, or Fig.17 X-ring 471 is shown.

[0053] like Fig. 20As shown, the fasteners 452 of the downhole tool 412 may be embedded in (eg, molded into) the material forming the end 478 of the outer sleeve 477 such that the material of the outer sleeve 477 fluidly isolates the fasteners 452 from the external space. Fig.21 The downhole tool 413 shown similarly has a fastener 454 embedded in the material forming the end 480 of the outer sleeve 479, so that the material of the outer sleeve 479 isolates the fastener 454 from the fluid of the external space. The ends 478, 480 of the outer sleeves 477, 479 can be thickened, such as to facilitate the fastener 452, 454 from the fluid of the external space. When the fastener 452, 454 presses the outer sleeve 477, 479 against the outer surface of the housing portion 312, 314, the thickened end 478, 480 of the outer sleeve 477, 479 can also help prevent or stop the fastener 452, 454 from piercing the outer sleeve 477, 479.

[0054] like Fig. 22 As shown, the fasteners 452 of the downhole tool 414 can each be covered by a corresponding additional sleeve (or layer) 481 of an elastomer, heat shrink material, or rigid material (e.g., as described above with respect to the outer sleeve 319), such that the fasteners 452 are located between the outer sleeves 319, 481 and are thus isolated from the external space fluid. In a similar manner, as Fig.23 As shown, the fastener 454 of the downhole tool 415 can be covered by a similar additional sleeve 482, so that the fastener 454 is isolated from the external space fluid. The material forming the additional sleeves 481, 482 can include the material forming the outer sleeve 319 or another material. Using one or more methods for setting the outer sleeve 318 around the above-mentioned sensor segment 310 and the housing parts 312, 314, including using one or more of the above-mentioned devices 316, 320 and / or heating the additional sleeves 481, 482 to radially shrink (or shrink) the additional sleeves 481, 482 to form a fluid seal around the fasteners 452, 454, the additional sleeves 481, 482 can be set around the fasteners 452, 454 and the outer sleeve 319 and extend circumferentially around the fasteners 452, 454 and the outer sleeve 319.

[0055] like Fig.24 As shown, the downhole tool 416 is similar to Fig. 22 The downhole tool 414 has a Fig.17 The outer sleeve 319 is provided with a circumferential groove 472, each groove containing a gasket 474. When the fastener 452 presses the outer sleeve 319 against the gasket 474, a fluid seal can be formed between the outer sleeve 319 and each gasket 474. The gasket 474 can also have a non-circular cross-sectional shape, such as a square or other rectangular shape, or Fig.17X-ring 471 is shown.

[0056] According to one or more aspects of the present disclosure, the radial fastener used with the downhole tool can be an elastic or heat shrink fastener. The main difference between the heat shrink fastener and the elastic fastener is that the diameter change range of the heat shrink fastener is relatively small, while the radial elastic fastener applies a stable compressive force in a relatively large diameter range, although the compressive force is relatively smaller than that of the heat shrink fastener. The elastic fastener can also follow the diameter change of the outer sleeve under pressure changes and can apply a stable compressive force.

[0057] like Fig.25 As shown, the downhole tool 417 includes elastic radial fasteners 483, each of which extends circumferentially around the outer sleeve 319 and presses the outer sleeve 319 against the corresponding housing parts 312, 314. Each fastener 483 can have an annular geometry. For example, each fastener 483 can be or include an elongated member (e.g., a rod, a sheet, etc.) formed by a flexible material (e.g., a metal, an elastomer, etc.) that is bent or otherwise bent to form a ring. Therefore, each fastener 483 can include a disconnected (or discontinuous) portion 484. The fastener 483 can have a rectangular or circular cross-sectional profile. The fastener 483 can expand in a radially outward direction, be arranged around the corresponding end of the outer sleeve 319, and then be allowed to elastically contract (or shrink) in a radially inward direction, thereby applying a radially inward force to press the outer sleeve 319 against the outer surface of the housing parts 312, 314. The downhole tool 417 may also include one or more fasteners 483 that press each end of the outer sleeve 319 against the housing portions 312 , 314 .

[0058] Figure 26-28 The downhole tools 418-420 shown in FIG. Fig.25 The exemplary embodiment of the downhole tool 417 shown in FIG. 4 includes areas indicated by common reference numerals. Fig.26 As shown, the fastener 483 of the downhole tool 418 presses the outer sleeve 319 against the outer surface of the housing parts 312, 314. Fig. 27 As shown, fasteners 483 of downhole tool 419 press outer sleeve 319 against gasket 474 contained in circumferential groove 472 in the outer surface of housing portions 312, 314. Fig.28As shown, the fastener 483 of the downhole tool 420 presses the thicker section 467 of the outer sleeve 466 against the outer surface of the housing portions 312, 314. Also as described above, the thicker sections 467 can each be disposed within a corresponding circumferential groove (or channel) 469 extending along the outer surface of the housing portions 312, 314. The thicker section 467 and the circumferential groove 469 can together facilitate positioning of the outer sleeve 466 around the intended axial position of the sensor segment 310.

[0059] The outer sleeve according to one or more aspects of the present disclosure may not provide sufficient long-term mechanical strength, for example when there are abrasive surfaces, sharp edges and / or shock vibration hazards. However, in various tested solutions, the combination between the outer sleeve and the one or more sensors 311 in the sensor section 310 of the downhole acoustic measurement tool and sufficient acoustic transparency of the outer sleeve are optimal. Therefore, in order to combine mechanical strength and acoustic transparency, multiple sleeves can be used, as described below.

[0060] Fig.29 is a schematic cross-sectional view of a portion of a downhole tool 421 including a plurality of sleeves 319 , 486 . Fig.30 is a schematic cross-sectional view of a portion of a downhole tool 422 including a plurality of sleeves 319, 488. The outer sleeves 486, 488 may be formed of an elastomer, a heat shrink material, or a rigid material, as described above with respect to the outer sleeve 319. The downhole tools 421, 422 are exemplary embodiments of one or more of the downhole tools described above, and include one or more features and / or operating modes of one or more of the downhole tools described above, including those indicated by common reference numerals.

[0061] like Fig.29 As shown, in addition to surrounding the sensor segment 310, the outer sleeve 486 covers the inner sleeve 319. Fig.30 As shown, the outer sleeve 488 covers the entire inner sleeve 319, including around the sensor segment 310. Each downhole tool 421, 422 also includes a fastener 485 that extends circumferentially around the inner and outer sleeves 319, 486, 488 and presses the inner and outer sleeves 319, 486, 488 against the outer surface of the housing portion 312, 314, thereby forming a fluid seal between the outer surface of the housing portion 312, 314 and the outer sleeve 318. The fastener 485 can be, for example, the fastener 452, 454 or 483 described above.

[0062] The present disclosure also relates to a fluid seal assembly including an axial compression fastener configured to compress an outer sleeve against a surface of a housing of a downhole tool. Fig.31is a schematic cross-sectional view of at least a portion of an exemplary embodiment of a downhole tool 501 according to one or more aspects of the present disclosure, the downhole tool 501 including an outer sleeve 319 and an axial compression fastener 510 configured to compress the outer sleeve 319 against the housing 202 of the downhole acoustic measurement tool 501. The downhole tool 501 may be an exemplary embodiment of one or more of the downhole tools described above and include one or more features and / or operating modes of the one or more of the downhole tools described above, including those indicated by common reference numerals.

[0063] The downhole tool 501 includes first and second fasteners 510, 512 formed of steel and / or other metals. The first fastener 510 has an annular geometry and is configured to be disposed circumferentially around the first housing portion 312. The first fastener 510 includes an internal thread 511 configured to engage an external thread 513 of the first housing portion 312. Rotation of the first fastener 510 causes the first internal thread 511 to engage the first external thread 513, thereby causing the first fastener 510 to move axially in a first direction, as indicated by arrow 504, and thereby apply a first axial force to the first end 518 of the outer sleeve 319 to press the first end 518 against the tapered outer surface 520 of the first housing portion 312.

[0064] The second fastener 512 has an annular geometry and is configured to be disposed circumferentially around the second housing portion 314. The second fastener 512 includes internal threads 511 configured to engage external threads 513 of the second housing portion 314. Rotation of the second fastener 512 causes the internal threads 511 to engage the external threads 513, thereby causing the second fastener 512 to move axially in a second direction, as indicated by arrow 506, thereby applying a second axial force to the second end 519 of the outer sleeve 319 to press the second end 519 of the outer sleeve 319 against the tapered surface 521 of the second housing portion 314.

[0065] The outer sleeve 319 and the fasteners 510, 512 may together be or form a fluid sealing component of the downhole tool 501. For example, the first end 518 of the outer sleeve 319 is pressed against the first surface 520 by the first fastener 510 to form a first fluid seal between the surface 520 and the first end 518 of the outer sleeve 319, and the second end 519 of the outer sleeve 319 is pressed against the surface 521 by the second fastener 512 to form a second fluid seal between the surface 521 and the second end 519 of the outer sleeve 319.

[0066] Fig.32is a schematic cross-sectional view of a portion of an exemplary embodiment of a downhole tool 502 according to one or more aspects of the present disclosure, the downhole tool 502 including an outer sleeve 319 and an axial compression fastener 532 configured to compress the outer sleeve 319 against the housing portion 312. The downhole tool 502 may be an exemplary embodiment of one or more of the downhole tools described above and include one or more features and / or operating modes of the one or more downhole tools described above, including those indicated by common reference numerals.

[0067] The fasteners 532 each have an annular geometry and are configured to be disposed circumferentially around a respective one of the housing portions 312, 314. The fasteners 532 may be identical such that Fig.32 Only one is shown in the drawings. The fastener 532 shown includes internal threads 511 that are configured to engage external threads 513 of the housing portion 312. Rotation of the fastener 532 causes the internal threads 511 to engage the external threads 513, thereby causing the fastener 532 to move axially, as shown by arrow 504, thereby applying an axial force to press the end 518 of the outer sleeve 319 against the outer surface 520 of the housing portion 312. The outer surface 520 can be an outer tapered surface or shoulder that expands radially outward along the axial direction 504 relative to the central axis 509. The material forming the fastener 532 can include a metal (e.g., steel).

[0068] The downhole tool 502 also includes push members 534, 536, each of which has an annular geometry and is configured to be disposed circumferentially around the housing portion 312 between the fastener 532 and the end 518 of the outer sleeve 319. The push member 536 can be an axial spring member, while the push member 534 can be a metal or other rigid member. Rotation of the fastener 532 causes the internal thread 511 to engage the external thread 513, thereby causing the fastener 532 to move axially, as shown by arrow 504, thereby applying an axial force to the end 518 of the outer sleeve 319 through the push members 534, 536 to press the end 518 of the outer sleeve 319 against the surface 520. The push member 534 has an inner tapered surface 535 that cooperates with the outer tapered surface 520 of the housing portion 312. The pushing member 536 has a predetermined axial stiffness (e.g., spring constant, elastic modulus, etc.), which can facilitate, for example, applying and maintaining a predetermined axial force to the intermediate member 534 through the fastener 532, and thereby pressing the end 518 of the outer sleeve 319 against the surface 520 with a predetermined axial force.

[0069] Fig.33is a schematic cross-sectional view of a portion of an exemplary embodiment of a downhole tool 503 according to one or more aspects of the present disclosure, the downhole tool 503 including an outer sleeve 319 and an axial compression fastener 542 configured to compress the outer sleeve 318 against the housing portions 312, 314. The downhole tool 503 may be an exemplary embodiment of one or more of the downhole acoustic measurement tools described above and include one or more features and / or operating modes of the one or more downhole acoustic measurement tools described above, including those indicated by common reference numerals.

[0070] The fasteners 542 each have an annular geometry and are configured to be disposed circumferentially around the respective housing portion 312, 314. The fasteners 542 may be identical, so that Fig.33 Only one is shown in the drawings. The illustrated fastener 542 includes internal threads 511 configured to engage external threads 513 of the housing portion 312. Rotation of the fastener 542 causes the internal threads 511 to engage the external threads 513, thereby causing the fastener 542 to move axially, as indicated by arrow 504, thereby applying an axial force to the end 518 of the outer sleeve 319 and pressing the end 518 of the outer sleeve 319 against the housing portion 312. The material forming the fastener 542 may include a metal (e.g., steel).

[0071] The fastener 542 includes a contact surface 543 and the housing portion 312 includes a complementary (i.e., corresponding or mating) surface 544. The surface 543 of the fastener 542 is configured to press the end 518 of the outer sleeve 319 against the surface 544 of the housing portion 312 when the fastener 542 moves axially in response to rotation. The surface 543 can be a side surface (or shoulder) extending perpendicularly (or radially) outwardly relative to the central axis 509. The surface 544 can be a side surface (or shoulder) extending perpendicularly (or radially) relative to the central axis 509. The surfaces 543, 544 can be parallel to each other.

[0072] The surface 544 may be at least partially defined by, or otherwise include, a circumferential profile 545 that is configured to seal against the end 518 of the outer sleeve 319. When the fastener 542 presses the end 518 of the outer sleeve 319 against the circumferential profile 545, a fluid seal may be formed between the end 518 of the outer sleeve 319 and the circumferential profile 545. The circumferential profile 545 may be defined by a gasket (or another fluid sealing element) 546 disposed within a circumferential groove 548 extending along the surface 544. The gasket 546 may include an X-shaped cross-section that defines the circumferential profile as a circumferential groove.

[0073] The downhole tool 503 also includes an intermediate member (or push member) 549 having an annular geometry and configured to be disposed circumferentially around the housing portion 312 between a surface 543 of the fastener 542 and a surface 544 of the housing portion 312. Rotation of the fastener 542 causes the internal threads 511 to engage the external threads 513, thereby causing the fastener 542 to move axially in the direction 504, thereby applying an axial force (via the intermediate member 549) to the end 518 of the outer sleeve 319 and pressing the end 518 of the outer sleeve 319 against the surface 544. The intermediate member 549 may be a ring having a circular cross-sectional profile configured to press the end 518 of the outer sleeve 319 against and / or into the profile 545 to form a fluid seal between the end 518 of the outer sleeve 319 and the circumferential profile 545. The material forming the intermediate member 549 may include a metal (e.g., steel), a polymer, or an elastomer.

[0074] The present disclosure also relates to an anti-extrusion filler disposed between an outer sleeve and an outer surface of a housing of a downhole acoustic measurement tool. Fig.34 and 35 Schematic cross-sectional views of portions of exemplary embodiments of downhole tools 602, 603, respectively, each of which includes an anti-extrusion filler according to one or more aspects of the present disclosure. Downhole tools 602, 603 may be exemplary embodiments of one or more of the above-described downhole tools, and include one or more features and / or operating modes of the above-described one or more downhole tools, including those indicated by common reference numerals.

[0075] Downhole tools 602, 603 each include a housing 202 including housing portions 312, 314 described above and a sensor segment 310 including an interior chamber 203 containing a sensor 311. Housing portions 312, 314 may together define at least a portion of interior chamber 203 containing sensor 311.

[0076] The housing portions 312, 314 and the sensor segment 310 may have a small gap therebetween, thereby forming or otherwise defining a gap 606 therebetween. These gaps may collectively form (or operate as) one or more fluid paths extending between the space outside the downhole tool 602, 603 (i.e., the outer surface of the housing portions) and the interior chamber 203. The one or more gaps 606 may terminate in one or more slots 612 extending along the outer surface of the housing 202.

[0077] The downhole tool 602, 603 also includes an outer sleeve 319 that is disposed circumferentially around the sensor segment 310 (including the internal chamber 203) and around the ends of the housing portions 312, 314 adjacent to the sensor segment 310. The downhole tool 602, 603 also includes a material 614 disposed inside the sleeve 319 to further prevent wellbore fluid from entering the slot 612. For example, the material 614 can be one or more gaskets and / or filler materials 614 disposed along the slot 612 between the outer sleeve 319 and the outer surface of the housing 202. The material 614 can be or include at least one of an epoxy, a silicone, a silicone rubber (e.g., a room temperature vulcanizing (RTV) resin), a rubber, or a polyetherimide.

[0078] The material 614 and the outer sleeve 319 can jointly prevent the wellbore fluid from flowing into the internal chamber 203 via the gap 606, thereby maintaining a pressure difference between the wellbore pressure in the wellbore and the internal pressure in the internal chamber 203 and the gap 606. For example, the material 614 and the outer sleeve 319 can be configured to prevent the wellbore fluid from flowing from the outside of the housing 202 into the internal chamber 203 via the slot 612 and the gap 606 when the downhole tools 602, 603 are transported in the wellbore. Therefore, the chamber 203 and the gap 606 can be maintained at an internal pressure (e.g., atmospheric pressure) lower than the wellbore pressure. Therefore, a pressure difference can be formed on the material 614 and the outer sleeve 319, wherein the wellbore pressure is higher than the internal pressure in the chamber 203 and the gap 606. The material 614 can be configured to be squeezed into the gap 606 via the slot 612 due to the pressure difference, thereby inhibiting the outer sleeve 319 from being squeezed into the gap 606 via the slot 612 due to the pressure difference. Thus, material 614 can be or form a sacrificial material (or component) that is configured to be squeezed into gap 606 via slot 612 by a pressure differential while preventing or inhibiting outer sleeve 319 from being squeezed into gap 606, thereby maintaining the structural integrity of outer sleeve 319.

[0079] Other embodiments of the downhole tool may incorporate different sealing mechanisms at each end of the outer sleeve 319. These sealing mechanisms may be any of the mechanisms described above. As an example, Fig.36 Such an embodiment of a downhole tool is depicted. The downhole tool may be substantially similar to the downhole tool shown here. The downhole tool may have a housing 202. The housing may have a portion 312 adjacent to a sensor segment 310 having one or more sensors 311. An outer sleeve 319 may be disposed around the housing 202.

[0080] The first fastener 510 and the second fastener 452 can jointly engage the outer sleeve to form a fluid-tight assembly of the downhole tool. For example, the first end 518 of the outer sleeve 319 is pressed against the first surface 520 by the first fastener 510 to form a first fluid seal between the surface 520 and the first end 518 of the outer sleeve 319. The first fastener can have an internal thread 511 to engage the external thread 513 on the housing portion 312.

[0081] When the second fastener 452 presses the outer sleeve 319 against the gasket, the fastener 452 can form a fluid seal between the outer sleeve 319 and one or more gaskets. The gasket can be an X-ring 471, but can also have a non-circular cross-sectional shape, such as a square or other rectangular shape. A gasket such as an X-ring 471 can be disposed in a circumferential slot 472 on the outer surface of the housing.

[0082] The Abstract of the Disclosure complies with 37 CFR §1.72(b) to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. A device comprising: a downhole tool including an acoustic sensor operable to transmit and receive acoustic signals to perform downhole measurements; and A fluid sealing assembly, the fluid sealing assembly comprising: a sleeve disposed circumferentially around the downhole tool, wherein the sleeve is sufficiently acoustically transparent to pass the transmitted and received acoustic signals; and A first fastener and a second fastener each extend circumferentially around the sleeve proximate respective first and second ends of the sleeve.

2. The device according to claim 1, wherein: A portion of the sleeve is disposed in front of the acoustic sensor; Other portions of the sleeve extend axially above and below the acoustic sensor; and At least the portion of the sleeve in front of the acoustic sensor is of uniform thickness.

3. The device according to claim 1, wherein the sleeve is made of a heat-shrinkable polymer so that due to temporary heat treatment, the sleeve is pressed against the outer surface of the downhole tool or the elastomer so that the sleeve is constantly pressed against the outer surface of the downhole tool, or the sleeve is made of a rigid material.

4. The apparatus of claim 1, wherein the first fastener is a first type of fastener, the second fastener is a second type of fastener, and wherein the first fastener is different from the second fastener.

5. The apparatus of claim 1 , wherein the first fastener and the second fastener comprise shape memory alloys such that due to an increase in temperature, a circumference of the first fastener and the second fastener decreases, thereby causing the first fastener and the second fastener to apply a radially inward force to the sleeve to press the sleeve against the outer surface of the downhole tool.

6. The apparatus of claim 1, wherein the first fastener and the second fastener are elastomeric such that the first fastener and the second fastener constantly press the sleeve against the outer surface of the downhole tool.

7. The device according to claim 1, wherein: The first fastener and the second fastener compress the sleeve against an outer surface of the downhole tool; and The sleeve is pressed against the outer surface of the downhole tool by the first fastener and the second fastener to form a fluid seal between the outer surface of the downhole tool and the sleeve.

8. The apparatus of claim 1, further comprising a first washer and a second washer positioned in respective first and second circumferential grooves extending into an outer surface of the downhole tool, wherein: The first and second fasteners press the sleeve against the respective first and second washers.

9. The apparatus of claim 8, wherein the first washer and the second washer each have a non-circular cross-sectional shape when not compressed by the sleeve or the first and second fasteners.

10. The device of claim 8, wherein the first gasket and the second gasket each have an X-shaped cross-section.

11. The device of claim 1, wherein the first fastener and the second fastener are embedded in the sleeve.

12. The device of claim 1, wherein the first end of the sleeve is wrapped around the first fastener, and wherein the second end of the sleeve is wrapped around the second fastener.

13. The device of claim 1, wherein the sleeve is a first sleeve, and wherein the fluid seal assembly further comprises a second sleeve extending around the first sleeve and the first fastener and a third sleeve extending around the first sleeve and the second fastener.

14. The device of claim 13, wherein the second sleeve and the third sleeve are made of a material selected from the group consisting of a heat shrink material, an elastomer, and a rigid material.

15. An apparatus comprising: a downhole tool including an acoustic sensor operable to transmit and receive acoustic signals to perform downhole measurements; and A fluid sealing assembly, the fluid sealing assembly comprising: a sleeve disposed circumferentially around the downhole tool, wherein the sleeve is sufficiently acoustically transparent to pass the transmitted and received acoustic signals; a first fastener disposed circumferentially about the downhole tool, wherein the first fastener includes first internal threads that engage first external threads of the downhole tool to thereby compress the first end of the sleeve against a first surface of the downhole tool; and A second fastener is disposed circumferentially around the downhole tool, wherein the second fastener includes second internal threads that engage second external threads of the downhole tool to thereby compress the second end of the sleeve against a second surface of the downhole tool.

16. The device according to claim 15, wherein: compressing the first end of the sleeve against the first surface via the first fastener to form a first fluid seal between the first surface and the first end of the sleeve; and The second end of the sleeve is pressed against the second surface by the second fastener to form a second fluid seal between the second surface and the second end of the sleeve.

17. The device of claim 15, wherein the sleeve is made of a material selected from the group consisting of a heat shrink material, an elastomer, and a rigid material.

18. The device of claim 15, wherein the fluid sealing assembly further comprises: a first intermediate member disposed circumferentially around the downhole tool between the first fastener and the first surface; and A second intermediate member is disposed circumferentially around the downhole tool between the second fastener and the second surface.

19. An apparatus comprising: A downhole tool, comprising: an acoustic sensor operable to transmit and receive acoustic signals to perform downhole measurements while the downhole tool is conveyed within the wellbore; a housing comprising a plurality of interconnected housing portions that collectively define at least a portion of an interior chamber containing the sensor, wherein adjacent housing portions define gaps that collectively form a fluid path between an exterior surface of the housing and the interior chamber, and wherein at least one of the gaps terminates in a slot extending along the exterior surface; a sleeve disposed circumferentially around the housing to prevent wellbore fluid from flowing into the interior chamber through the gap when the downhole tool is conveyed within the wellbore; and A material disposed within the casing that further prevents wellbore fluid from entering the slot.

20. The device according to claim 19, wherein the sleeve is made of a heat-shrinkable polymer so that due to temporary heat treatment, the sleeve is pressed against the outer surface of the downhole tool or an elastomer so that the sleeve is constantly pressed against the outer surface of the downhole tool, or the sleeve is made of a rigid material.

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