Formation test probe and formation tester

Abstract

The invention relates to a formation test probe and a formation test.The formation test probe comprises a probe base and setting rubber, the setting rubber is fixed to the side, close to the well wall, of the probe base, a filter screen is arranged in a circular ring defined by the setting rubber, the filter screen is limited to the probe base, an elastic structure is arranged between the filter screen and the probe base, and the elastic structure is fixed to the side, close to the well wall, of the probe base. After the setting rubber makes contact with the well wall, the filter screen can compress the elastic structure to move in the direction close to the sealing base under the acting force of the well wall so that the setting rubber can be set on the corresponding well wall, and the filter screen is used for supporting the inner ring face of the setting rubber in the setting process and filtering fluid in the suction process. The filter screen can limit the inward deformation of the setting rubber under the action of shear force in the setting process, so that the situation that the setting rubber cracks due to the internal and external pressure difference in the setting process can be reduced, the situation that the setting rubber is torn due to the cracks is reduced, and the purpose of improving the setting success rate is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of formation sampling, and in particular relates to a formation testing probe and a formation tester. Background Art

[0002] When the formation tester is working underground, the hydraulic system first drives the sealing rubber in the formation test probe to seal on the well wall, so that the target formation is isolated from the external mud; then the formation fluid is sucked through the fluid channel, and the sucked formation fluid is used to detect formation parameters.

[0003] In actual engineering applications, it is found that the sealing rubber often produces cracks due to the shearing of the sealing rubber by the large internal and external pressure. These cracks are very likely to accelerate with the increase of the internal and external pressure difference, and eventually cause the sealing rubber to tear or fall off. Therefore, a formation test probe is provided, which can well solve the problem of the sealing rubber tearing due to the shear force on the sealing rubber. Summary of the invention

[0004] In order to solve all or part of the above-mentioned problems, the purpose of the present invention is to provide a formation testing probe and a formation tester. The filter of the formation testing probe of the present invention can limit the inward deformation of the sealing rubber due to the shear force during the setting process, thereby reducing the occurrence of cracks in the sealing rubber due to the internal and external pressure difference during the setting process.

[0005] According to one aspect of the present invention, a formation test probe is provided, comprising a probe base and a setting rubber, wherein the outer surface of the setting rubber close to the well wall cooperates with the well wall surface, and is characterized in that:

[0006] A filter is arranged in the circular ring surrounded by the setting rubber, and the filter is limited on the probe base. An elastic structure is arranged between the filter and the probe base. After the setting rubber contacts the well wall, the filter can compress the elastic structure and move it toward the sealing base under the force of the well wall, so that the setting rubber can be set on the corresponding well wall. The filter is used to support the inner annular surface of the setting rubber during the setting process and to filter the fluid during the suction process.

[0007] Further, the hardness of the elastic structure is less than the hardness of the setting rubber, and the elastic structure is a circle of filter rubber arranged between the filter and the probe base;

[0008] The outer surface of the probe base close to the setting rubber is matched with the well wall surface.

[0009] Furthermore, in the process of the setting rubber approaching the well wall, the filter is configured to keep the elastic structure in a natural state or a compressed state; and in the process of the setting rubber approaching the well wall, the outer surface of the filter close to the well wall overlaps with the outer surface of the setting rubber close to the well wall.

[0010] Further, the filter screen is limited on the probe base by a plurality of guide limiters, and in the process of the setting rubber approaching the well wall, the filter screen is configured to make the elastic structure in a natural state or a compressed state by a plurality of the guide limiters;

[0011] The filter screen can compress the elastic structure to move toward the sealing base relative to the plurality of guide limit members under the force of the well wall, so that the setting rubber can be set on the corresponding well wall.

[0012] Furthermore, each of the guide limit members is a guide limit screw, and a plurality of stepped holes are opened on the outer circumference of the filter screen. The small hole of each of the stepped holes is arranged close to the sealing base, and the screw head of each of the guide limit screws is respectively located in the large hole of the corresponding stepped hole, and the diameter of each of the screw heads is larger than the diameter of the small hole of the corresponding stepped hole. The screw rod of each of the guide limit screws passes through the corresponding stepped hole and is fixedly connected to the probe base; in the process of the sealing rubber approaching the well wall, the screw head of the guide limit screw is pressed on the small hole of the stepped hole.

[0013] Furthermore, the thickness of the screw head is smaller than the depth of the large hole of the stepped hole.

[0014] Furthermore, the sealing rubber includes a first sealing rubber and a second sealing rubber, the hardness of the first sealing rubber is greater than the hardness of the second sealing rubber, the hardness of the second sealing rubber is greater than the hardness of the elastic structure, the second sealing rubber is located between the first sealing rubber and the filter screen, and the first sealing rubber and the second sealing rubber can both be sealed on the well wall.

[0015] Furthermore, outer surfaces of the first setting rubber and the second setting rubber on the side close to the well wall both cooperate with the well wall, and in the process of the setting rubber approaching the well wall, the second setting rubber contacts the well wall before the first setting rubber contacts the well wall, and the filter screen and the second setting rubber contact the well wall at the same time.

[0016] Furthermore, the probe base is fixed on the sealing base by fastening screws, and a sealing ring is arranged between the probe base and the sealing base.

[0017] The present invention also provides a formation tester, comprising any one of the above formation test probes.

[0018] It can be seen from the above technical solutions that the formation test probe and formation tester provided by the present invention have the following beneficial effects:

[0019] The formation test probe of the present invention includes a filter screen, which is supported on the inner ring surface of the sealing rubber. The setting of the filter screen can limit the inward deformation of the sealing rubber due to the shear force during the setting process, thereby reducing the occurrence of cracks in the sealing rubber due to the internal and external pressure difference during the setting process, and reducing the occurrence of tearing caused by cracks, thereby achieving the purpose of improving the success rate of the setting; and the setting of the filter screen can also prevent large particles of sandstone in the formation from being sucked into the instrument pipeline, causing pipeline blockage.

[0020] The first setting rubber and the second setting rubber of the formation testing probe of the present invention are both set on the well wall, thereby improving the sealing success rate.

[0021] The outer surface of the probe base of the formation testing probe of the present invention, which is close to the sealing rubber, cooperates with the well wall surface, so that the thickness of the first sealing rubber and the second sealing rubber can be uniform, thereby ensuring that during the sealing process, the forces on the first sealing rubber and the second sealing rubber are always evenly distributed on the entire arc surface, thereby avoiding damage to the first sealing rubber and / or the second sealing rubber due to stress concentration.

[0022] The hardness of the elastic structure of the formation test probe of the present invention is less than the hardness of the sealing rubber, that is, the setting of the elastic structure during the sealing process will not affect the smooth deformation of the sealing rubber; and when the filter rubber is used as the elastic structure, the filter will not be stuck during the sealing process due to sand and gravel entering the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a main cross-sectional view of a formation test probe according to an embodiment of the present invention;

[0024] Figure 2 It is a side view of a formation testing probe according to an embodiment of the present invention;

[0025] Figure 3 A top view of a formation test probe according to an embodiment of the present invention;

[0026] The reference numerals in the figure are: a setting rubber 1, a first setting rubber 111, a second setting rubber 122, a filter screen 2, a guide limit screw 3, an elastic structure 4, a probe base 5, a sealing base 6, a fastening screw 7, and a sealing ring 8. DETAILED DESCRIPTION

[0027] In order to better understand the purpose, structure and function of the present invention, a formation test probe and a formation tester of the present invention are further described in detail below with reference to the accompanying drawings.

[0028] like Figure 1-Figure 3 As shown, it shows a formation test probe of an embodiment of the present invention, including a probe base 5 and a sealing rubber 1, the sealing rubber 1 is fixed to the side of the probe base 5 close to the well wall, for example, the sealing rubber 1 is fixed to the probe base 5 by glue injection, and the outer surface of the sealing rubber 1 close to the well wall is an arc surface that cooperates with the well wall, so that the sealing rubber 1 can be sealed on the well wall.

[0029] A filter screen 2 is arranged in the circular ring surrounded by the setting rubber 1, and the filter screen 2 is limited on the probe base 5. An elastic structure 4 is arranged between the filter screen 2 and the probe base 5. After the setting rubber 1 contacts the well wall, the filter screen 2 can compress the elastic structure 4 and move it toward the sealing base 6 under the action of the well wall, so that the setting rubber 1 can be set on the corresponding well wall. The filter screen 2 is used to support the inner ring surface of the setting rubber 1 during the setting process and to filter the fluid during the suction process.

[0030] By setting the filter 2 to support the inner ring surface of the setting rubber 1, the pressure difference between the inner and outer ring surfaces of the setting rubber 1 can be reduced during the setting process, thereby reducing the occurrence of cracks in the setting rubber 1 due to shearing of internal and external pressures during the setting process, and reducing the occurrence of tearing caused by cracks, thereby achieving the purpose of improving the success rate of setting. Secondly, the setting of the filter 2 can also prevent large particles of sandstone in the formation from being sucked into the instrument pipeline, causing pipeline blockage. The filter 2 is a metal filter 2.

[0031] The elastic structure 4 of this embodiment is arranged between the filter screen 2 and the probe base 5. The arrangement of the elastic structure 4, on the one hand, enables the filter screen 2 to be compressed and moved in the direction close to the sealing base 6 under the force of the well wall, thereby providing space for the compression deformation of the sealing rubber 1 during the sealing process, so that the sealing rubber 1 can be smoothly sealed on the well wall; on the other hand; during the sealing process, the filter screen 2 can always be supported on the inner ring surface of the sealing rubber 1 under the action of the reset force of the elastic structure 4; the third aspect is that it is also convenient for the filter screen 2 to be reset after the sealing rubber 1 is separated from the well wall at the end of the sealing process. The reset of the filter screen 2 under the action of the elastic structure 4 can play a role in supporting the sealing rubber 1 in the next sealing process.

[0032] Specifically, during the sealing process, the pushing force acts on the sealing base 6, and the sealing base 6 carries the probe base 5 and the filter 2 and is pushed toward the well wall. After the probe base 5 contacts the well wall, as the pushing force increases, the sealing rubber 1 begins to be compressed. On the one hand, the filter 2 is supported on the inner ring surface of the sealing rubber 1, thereby reducing the pressure difference between the inner and outer ring surfaces of the sealing rubber 1 during the sealing process. On the other hand, the filter 2 compresses the elastic structure 4 and moves toward the sealing base 6 under the force of the well wall, thereby providing space for the compression deformation of the sealing rubber 1, so that the sealing rubber 1 can be compressed and deformed smoothly, and finally the sealing rubber 1 is sealed on the well wall.

[0033] In this embodiment, the hardness of the elastic structure 4 is less than that of the setting rubber 1, that is, the elastic structure 4 is more easily deformed than the setting rubber 1 during the setting process, so the setting of the elastic structure 4 will not affect the smooth deformation of the setting rubber 1, that is, it will not affect the setting of the setting rubber 1. As an alternative, the hardness of the elastic structure 4 can also be set to be equal to the hardness of the setting rubber 1.

[0034] In specific implementation, for example, the elastic structure 4 is a circle of filter screen 2 rubber disposed between the filter screen 2 and the probe base 5; the filter screen 2 rubber in this embodiment is a solid structure, so the filter screen 2 will not be stuck during the setting process due to sand and gravel entering the filter screen 2. After the filter screen 2 is stuck, the filter screen 2 cannot move toward the direction close to the sealing base 6, which will cause the setting failure. As an alternative, the elastic structure 4 can also be an elastic element such as a spring or a disc spring.

[0035] Finally, the outer surface of the probe base 5 close to the setting rubber 1 matches with the well wall surface. Specifically, the well wall is a cylindrical structure, and the side of the setting rubber 1 close to the well wall is an arc surface matching with the well wall surface, and the outer surface of the probe base 5 close to the setting rubber 1 is also an arc surface matching with the well wall surface, so that the thickness of the setting rubber 1 can be uniform, so that the force of the setting rubber 1 is always evenly distributed on the entire arc surface during the setting process, so that the setting rubber 1 can be prevented from being damaged due to stress concentration.

[0036] In the process of the setting rubber 1 approaching the well wall, the filter screen 2 is configured to make the elastic structure 4 in a natural state or a compressed state. Since the elastic structure 4 is in a natural state or a compressed state, the filter screen 2 will not move in the direction close to the sealing base 6 when the filter screen 2 is not subjected to external forces such as the force of the well wall. In the process of the setting rubber 1 approaching the well wall, the outer surface of the filter screen 2 close to the well wall overlaps with the outer surface of the setting rubber 1 close to the well wall. The overlap of the two makes the filter screen 2 and the setting rubber 1 contact with the well wall at the same time. Since the filter screen 2 is not subjected to external forces such as the force of the well wall, the filter screen 2 will not move in the direction close to the sealing base 6, so the filter screen 2 can play the purpose of supporting the inner annular surface of the setting rubber 1 after the setting rubber 1 contacts the well wall.

[0037] In one embodiment, the filter screen 2 is limited on the probe base 5 by a plurality of guide limiters, and in order to enable the filter screen 2 to support the inner annular surface of the setting rubber 1 after the setting rubber 1 contacts the well wall, the filter screen 2 is configured to keep the elastic structure 4 in a natural state or a compressed state by a plurality of guide limiters during the process of the setting rubber 1 approaching the well wall. Again, in order to enable the filter screen 2 to compress the elastic structure 4 to make way for the setting rubber 1 so that the setting rubber 1 can be smoothly set on the well wall, the filter screen 2 of this embodiment can compress the elastic structure 4 to move in the direction close to the sealing base 6 relative to the plurality of guide limiters under the force of the well wall.

[0038] In one embodiment, each guide limit member is a guide limit screw 3, and a plurality of stepped holes are opened on the outer circumference of the filter screen 2. The small hole of each stepped hole is arranged close to the sealing base 6. The screw head of each guide limit screw 3 is respectively located in the large hole of the corresponding stepped hole, and the diameter of each screw head is larger than the diameter of the small hole of the corresponding stepped hole. The screw rod of each guide limit screw 3 passes through the corresponding stepped hole and is fixedly connected to the probe base 5; in the process of setting the sealing rubber 1 close to the well wall, the screw head of the guide limit screw 3 is pressed on the small hole of the stepped hole.

[0039] In this embodiment, the filter screen 2 is limited on the probe base 5 by a plurality of guide limit screws 3, and in the process of the sealing rubber 1 approaching the well wall, the screw head of the guide limit screw 3 presses on the small hole of the stepped hole, and the elastic structure 4 is in a natural state or a compressed state. At this time, the outer surface of the filter screen 2 close to the well wall coincides with the outer surface of the sealing rubber 1 close to the well wall, so in the process of the sealing rubber 1 gradually approaching the well wall, the filter screen 2 and the sealing rubber 1 are in contact with the well wall at the same time. When the pushing force continues to increase, the filter screen 2 compresses the elastic structure 4 relative to the plurality of guide limiters to move close to the sealing base 6.

[0040] In the case where the elastic structure 4 is the rubber of the filter screen 2, in a specific implementation, for example, the screw rod of the guide limit screw 3 passes through the rubber of the filter screen 2 and is fixedly connected to the probe base 5. In the case where the elastic structure 4 is a spring, in a specific implementation, for example, each spring is respectively sleeved on the screw rod of the corresponding guide limit screw 3.

[0041] In addition, the thickness of the screw head must be less than the depth of the large hole of the stepped hole, so that the screw head does not hinder the compression deformation of the setting rubber 1. The filter screen 2 of this embodiment achieves linear displacement through the guide limit screw, and the use of the guide limit screw has the advantage of convenient installation.

[0042] In one embodiment, the sealing rubber 1 includes a first sealing rubber 11 and a second sealing rubber 12, the hardness of the first sealing rubber 11 is greater than the hardness of the second sealing rubber 12, the hardness of the second sealing rubber 12 is greater than the hardness of the elastic structure 4, and the second sealing rubber 12 is located between the first sealing rubber 11 and the filter 2, and both the first sealing rubber 11 and the second sealing rubber 12 can be sealed on the well wall.

[0043] The setting rubber 1 of this embodiment includes a first setting rubber 11 and a second setting rubber 12. Since the hardness of the first setting rubber 11 is greater than that of the second setting rubber 12, and the hardness of the second setting rubber 12 is greater than that of the elastic structure 4, during the setting process, the elastic structure 4 is easier to deform than the second setting rubber 12, and the second setting rubber 12 is easier to deform than the first setting rubber 11. Therefore, the first setting rubber 11 can be smoothly set on the well wall, and the second setting rubber 12 can be smoothly set on the well wall. During the setting process, the second setting rubber 12 supports the inner annular surface of the first setting rubber 11, and the filter screen 2 supports the inner annular surface of the second setting rubber 12, thereby also reducing the pressure difference between the internal and external forces on the first setting rubber 11 and the second setting rubber 12.

[0044] The sealing rubber 1 of this embodiment adopts a soft and hard two-layer structure, in which the inner rubber layer is soft rubber and the outer rubber layer is hard rubber. As the sealing force increases, the first sealing rubber 11 and the second sealing rubber 12 can both be sealed on the well wall, thereby improving the sealing success rate.

[0045] Again, the outer surfaces of the first and second setting rubbers 11, 12 on the side close to the well wall are both in line with the well wall, and in the process of the setting rubber 1 approaching the well wall, the second setting rubber 12 contacts the well wall before the first setting rubber 11 contacts the well wall, and the filter screen 2 and the second setting rubber 12 contact the well wall at the same time.

[0046] This arrangement can ensure that the inner second sealing rubber 12 contacts the well wall first during setting, and the filter screen 2 and the second sealing rubber 12 contact the well wall at the same time, and the second sealing rubber 12 is supported by the filter screen 2; as the setting force increases, the second sealing rubber 12 begins to be compressed, and the outer first sealing rubber 11 also begins to contact the well wall, and finally, the first sealing rubber 11 and the second sealing rubber 12 are both set on the well wall. This embodiment improves the sealing success rate by double-layer sealing of soft and hard rubber.

[0047] In one embodiment, the probe base 5 is fixed to the sealing base 6 by means of a fastening screw 7, and a sealing ring 8 is provided between the probe base 5 and the sealing base 6. In this embodiment, the probe base 5 and the sealing base 6 are sealed by the sealing ring 8 and fastened by the fastening screw 7, so that the probe base 5 is easy to disassemble and the probe base 5 is easy to replace. The embodiment of the present invention also provides a formation tester, comprising a formation test probe according to any one of the above embodiments.

[0048] The formation test probe of this embodiment includes a filter screen, which is supported on the inner ring surface of the setting rubber. The setting of the filter screen can limit the inward deformation of the setting rubber under the shear force during the setting process, thereby reducing the occurrence of cracks in the setting rubber due to the internal and external pressure difference during the setting process, and reducing the occurrence of tearing caused by cracks, thereby achieving the purpose of improving the success rate of setting. The setting of the filter screen can also prevent large particles of sandstone in the formation from being sucked into the instrument pipeline, causing pipeline blockage.

[0049] The first setting rubber and the second setting rubber of the formation test probe of this embodiment are both set on the well wall, thereby improving the sealing success rate.

[0050] The outer surface of the probe base of the formation test probe of this embodiment, close to the sealing rubber, cooperates with the well wall surface, so that the thickness of the first sealing rubber and the second sealing rubber can be uniform, thereby ensuring that during the sealing process, the force on the sealing rubber is always evenly distributed on the entire arc surface, thereby avoiding damage to the sealing rubber due to stress concentration.

[0051] The hardness of the elastic structure of the formation test probe in this embodiment is less than the hardness of the setting rubber, that is, the setting of the elastic structure during the setting process will not affect the smooth deformation of the setting rubber. And when the filter rubber is used as the elastic structure, the filter will not be stuck during the setting process due to sand and stone entering the filter.

[0052] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0053] In addition, the terms "one", "two", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0054] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A formation testing probe, comprising a probe base and a setting rubber, wherein the outer surface of the setting rubber close to the well wall is matched with the well wall surface, characterized in that: A filter is arranged in the circular ring surrounded by the setting rubber, and the filter is limited on the probe base. An elastic structure is arranged between the filter and the probe base. After the setting rubber contacts the well wall, the filter can compress the elastic structure and move it toward the sealing base under the force of the well wall, so that the setting rubber can be set on the corresponding well wall. The filter is used to support the inner annular surface of the setting rubber during the setting process and to filter the fluid during the suction process.

2. The formation testing probe according to claim 1, characterized in that: The hardness of the elastic structure is less than the hardness of the setting rubber, and the elastic structure is a circle of filter rubber arranged between the filter and the probe base; The outer surface of the probe base close to the setting rubber is matched with the well wall surface.

3. The formation testing probe according to claim 1, characterized in that: During the process of the setting rubber approaching the well wall, the filter is configured to keep the elastic structure in a natural state or a compressed state; and during the process of the setting rubber approaching the well wall, the outer surface of the filter close to the well wall overlaps with the outer surface of the setting rubber close to the well wall.

4. The formation testing probe according to claim 3, characterized in that: The filter screen is limited on the probe base by a plurality of guide limiters, and when the setting rubber is close to the well wall, the filter screen is configured to make the elastic structure in a natural state or a compressed state by a plurality of guide limiters; The filter screen can compress the elastic structure to move toward the sealing base relative to the plurality of guide limit members under the force of the well wall, so that the setting rubber can be set on the corresponding well wall.

5. The formation testing probe according to claim 4, characterized in that: Each of the guide limit members is a guide limit screw, and a plurality of stepped holes are provided on the outer circumference of the filter screen. The small hole of each of the stepped holes is arranged close to the sealing base, and the screw head of each of the guide limit screws is respectively located in the large hole of the corresponding stepped hole, and the diameter of each of the screw heads is larger than the diameter of the small hole of the corresponding stepped hole. The screw rod of each of the guide limit screws passes through the corresponding stepped hole and is fixedly connected to the probe base; in the process of the sealing rubber approaching the well wall, the screw head of the guide limit screw is pressed on the small hole of the stepped hole.

6. The formation testing probe according to claim 5, characterized in that: The thickness of the screw head is smaller than the depth of the large hole of the stepped hole.

7. The formation testing probe according to claim 1, characterized in that: The sealing rubber includes a first sealing rubber and a second sealing rubber, the hardness of the first sealing rubber is greater than the hardness of the second sealing rubber, the hardness of the second sealing rubber is greater than the hardness of the elastic structure, the second sealing rubber is located between the first sealing rubber and the filter screen, and both the first sealing rubber and the second sealing rubber can be sealed on the well wall.

8. The formation testing probe according to claim 7, characterized in that: The outer surfaces of the first setting rubber and the second setting rubber on the side close to the well wall both cooperate with the well wall, and in the process of the setting rubber approaching the well wall, the second setting rubber contacts the well wall before the first setting rubber contacts the well wall, and the filter screen and the second setting rubber contact the well wall at the same time.

9. The formation testing probe according to claim 1, characterized in that: The probe base is fixed on the sealing base by fastening screws, and a sealing ring is arranged between the probe base and the sealing base.

10. A formation tester, characterized in that: The invention comprises a formation testing probe as described in any one of claims 1 to 9.

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