CN112814638A - Ground stress measuring downhole device and hydraulic fracturing ground stress measuring system - Google Patents
Ground stress measuring downhole device and hydraulic fracturing ground stress measuring system Download PDFInfo
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- CN112814638A CN112814638A CN202110100194.2A CN202110100194A CN112814638A CN 112814638 A CN112814638 A CN 112814638A CN 202110100194 A CN202110100194 A CN 202110100194A CN 112814638 A CN112814638 A CN 112814638A
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- 239000007788 liquid Substances 0.000 claims abstract description 61
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 136
- 238000005259 measurement Methods 0.000 claims description 40
- 230000000903 blocking effect Effects 0.000 claims description 19
- 238000012546 transfer Methods 0.000 claims description 14
- 230000009471 action Effects 0.000 claims description 7
- 230000006835 compression Effects 0.000 claims description 7
- 238000007906 compression Methods 0.000 claims description 7
- 238000005553 drilling Methods 0.000 abstract description 22
- 238000007789 sealing Methods 0.000 description 20
- 238000002347 injection Methods 0.000 description 8
- 239000007924 injection Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 7
- 238000004891 communication Methods 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 230000004323 axial length Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/261—Separate steps of (1) cementing, plugging or consolidating and (2) fracturing or attacking the formation
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
A ground stress measuring underground device and a hydraulic fracturing ground stress measuring system relate to the technical field of hydraulic fracturing ground stress measuring systems, the ground stress measuring underground device comprises a first packer, a second packer and a fracturing center rod, the fracturing center rod is connected between the first packer and the second packer, and an inner cavity of the fracturing center rod, an inner cavity of the first packer and an inner cavity of the second packer are communicated; the fracturing center rod is provided with a one-way adjusting switch, the one-way adjusting switch comprises a liquid outlet passage and an adjusting component arranged on the liquid outlet passage, the liquid outlet passage penetrates through the side wall of the fracturing center rod, the difference value between the pressure of an inner cavity of the fracturing center rod and the pressure of the outer side is X, the adjusting component is used for opening the liquid outlet passage when the X is larger than a pressure set value, and closing the liquid outlet passage when the X is smaller than or equal to the pressure set value. The underground device for measuring the ground stress adopts the one-way adjusting switch, does not need to be pushed or pulled, is suitable for drilling holes with various angles in the axial direction, and is more widely applied.
Description
Technical Field
The invention relates to the technical field of hydrofracturing ground stress measurement systems, in particular to a ground stress measurement underground device and a hydrofracturing ground stress measurement system.
Background
The hydraulic fracturing ground stress measuring system is divided into a single-loop hydraulic fracturing ground stress measuring system and a double-loop hydraulic fracturing ground stress measuring system. The double-loop hydrofracturing ground stress measuring system needs to input two water paths into a drill hole from the ground, is generally not applicable when the test depth is deeper, and generally uses the single-loop hydrofracturing ground stress measuring system at the moment. The single-loop hydrofracturing ground stress measurement system uses an underground push-pull valve to convert a water path, and the functions of packer setting, packer section fracturing, underground water drainage and the like are respectively realized. The push-pull valve is a downhole waterway change-over switch, and when the push-pull valve is completely pulled open, water in the drill rod enters the packer to expand the packer so as to perform setting. When the push-pull valve is completely closed, water in the drill rod enters the middle packing fracturing section to perform a fracturing test. After the fracturing test is finished, if the drilled hole is dry or the water level is deep, the push-pull valve needs to be pulled to the middle position for draining. Because the seat seals and fractures the water that is different passageways, consequently, need to have two waterway channels in first packer, one is packer seat water waterway channel, and one is middle packing fracture section waterway channel.
The single-loop hydrofracturing ground stress measuring system applying the push-pull valve is only suitable for drilling holes vertically downward or downward, when the drilling holes vertically upward or upward, the push-pull valve cannot be completely pulled due to the fact that the push-pull valve needs to be completely pulled for sealing, and the push-pull valve cannot be used when the drilling holes vertically upward or upward under the action of gravity; the sealing ring in the push-pull valve is easy to wear, needs to be replaced frequently, and is complex to maintain. In conclusion, the single-loop hydrofracturing ground stress measurement system in the prior art is narrow in application range and cannot be applied to application scenes that a drill hole is vertically upward or upward.
Disclosure of Invention
The invention aims to provide a ground stress measuring downhole device and a hydraulic fracturing ground stress measuring system, which can solve the technical problems to a certain extent.
The invention is realized by the following steps:
a ground stress measurement downhole device, comprising: the packer comprises a first packer, a second packer and a fracturing center rod, wherein the fracturing center rod is connected between the first packer and the second packer, and an inner cavity of the fracturing center rod, an inner cavity of the first packer and an inner cavity of the second packer are communicated;
the fracturing center rod is provided with a one-way adjusting switch, the one-way adjusting switch comprises an adjusting component and a liquid outlet passage, the liquid outlet passage penetrates through the side wall of the fracturing center rod, the adjusting component is arranged on the liquid outlet passage, the difference value between the pressure of an inner cavity of the fracturing center rod and the pressure of the outer side is X, the adjusting component opens the liquid outlet passage under the action of water pressure when the X is larger than a pressure set value, and the adjusting component closes the liquid outlet passage when the X is smaller than or equal to the pressure set value.
In a feasible implementation scheme, two opposite ends of the liquid outlet passage are divided into a first end and a second end, the first end is provided with a first opening, the second end is provided with a second opening, the adjusting assembly is arranged on the liquid outlet passage and comprises a blocking piece and an elastic resetting piece, the elastic resetting piece is arranged between the blocking piece and the second end, the blocking piece can move along the liquid outlet passage, and the blocking piece can be blocked at the first opening.
In a possible embodiment, the blocking element is a ball and/or the elastic return element is a spring.
In a possible implementation, the one-way adjusting switch further comprises a pressure adjusting piece, at least part of the structure of the pressure adjusting piece extends into the liquid outlet passage, and the pressure adjusting piece is abutted against the elastic resetting piece and used for adjusting the initial compression amount of the elastic resetting piece.
In a feasible implementation, the pressure adjusting member includes a hollow screw, the hollow screw is disposed at the second end of the liquid outlet passage, a hollow cavity of the hollow screw axially penetrates through the hollow screw, the hollow cavity is communicated with the second opening, and one end of the hollow screw extends into the liquid outlet passage from the second opening and abuts against the elastic reset member.
In a possible implementation scheme, the side wall of the fracturing center rod is provided with a plurality of one-way adjusting switches, and the pressure setting values corresponding to the one-way adjusting switches are different.
In one possible embodiment, the geostress measuring downhole device further comprises a drain valve connected to the first packer.
In one possible embodiment, the drain valve comprises a valve body and a valve core rod, the valve body is connected with the first packer, one end of the valve core rod extends into the inner cavity of the valve body, the other end of the valve core rod is used for being connected with a drill rod, and the valve core rod can move relative to the inner cavity of the valve body to move between a first position and a second position; the valve body comprises a transfer waterway and a water discharge opening, and the transfer waterway is communicated with an inner cavity of the first packer; the valve core rod is provided with a water inlet passage, the water inlet passage is provided with a first water passing port and a second water passing port, the first water passing port is communicated with the transfer waterway at the first position, and the second water passing port is communicated with the water drainage port at the second position.
In a possible embodiment, the ground stress measuring downhole device further comprises a downhole pressure sensor mounted on an outer wall of the fracturing center rod.
A hydraulic fracturing ground stress measuring system comprises a drill pipe, a high-pressure pump and a ground stress measuring downhole device provided by any one of the technical schemes, wherein the high-pressure pump is used for injecting water into the ground stress measuring downhole device through the drill pipe.
The beneficial effects of the invention at least comprise:
in the process of carrying out ground stress measurement, because the inner chamber of first packer, the inner chamber of the well core rod of fracturing and the inner chamber intercommunication of second packer, therefore the water injection pipeline is one, and after the water injection, first packer and second packer expand under the water pressure effect to play and seal the effect. After a certain amount of water is injected, the pressure of the inner cavity of the fracturing center rod is gradually increased, when the pressure of the inner cavity of the fracturing center rod is larger than the pressure of the outer side by a pressure set value, the adjusting assembly opens the liquid outlet passage, and water flows out of the liquid outlet passage to the outer side of the fracturing center rod, namely the space between the first packer and the second packer. After the water fractures the well wall between the first packer and the second packer, the outside pressure of the fracturing center rod is reduced, the adjusting assembly closes the liquid outlet pipeline, and the outward water injection is stopped.
Because the regulating assembly automatically opens and closes the liquid outlet passage under the action of water pressure, the starting and stopping control of outward drainage of the automatic fracturing center rod can be realized without arranging a push-pull valve. Because the adjusting component opens and closes the liquid outlet passage under the action of pressure, the device can be applied regardless of the drilling direction, and has wider application range.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic structural diagram of a unidirectional adjustment switch in a ground stress measurement downhole device provided by an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a ground stress measurement downhole device according to an embodiment of the present invention;
FIG. 3 is a cross-sectional view of a geostress measurement downhole device provided in accordance with an embodiment of the invention;
FIG. 4 is a schematic structural diagram of a ground stress measurement downhole device according to a second embodiment of the present invention;
FIG. 5 is a cross-sectional view of a second embodiment of a geostress measuring downhole device of the invention in a first state;
FIG. 6 is an enlarged fragmentary view of the bleed valve of FIG. 5;
FIG. 7 is a cross-sectional view of a second embodiment of a geostress measuring downhole device provided in accordance with the present invention in a second condition;
FIG. 8 is an enlarged fragmentary view of the bleed valve of FIG. 7;
fig. 9 is a sectional view of a valve body of a drain valve in a ground stress measuring downhole device according to a second embodiment of the present invention.
In the figure:
10-a first packer; 11-a first lumen;
20-a second packer; 21-a second lumen; 22-plug;
30-fracturing the center rod; 31-a third lumen;
40-one-way regulating switch; 41-a first opening; 42-a second opening; 43-liquid outlet passage; 44-a closure; 45-elastic return member; 46-hollow screw; 47-a housing;
50-a water escape valve;
51-a spool rod; 511-water inlet path; 512-a first overflow port; 513-a second water passing opening;
52-a valve body; 521-a transit waterway; 522-water discharge opening; 523-first valve body; 524-a second valve body; 525-pressure relief port;
53-a fourth chamber;
54-a first seal ring; 55-a second sealing ring;
60-a pressure sensor; 70-a drill rod; 80-connecting pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the equipment or elements that are referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Some embodiments of the invention are described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.
First embodiment
Referring to fig. 1 to 3, the present embodiment provides a downhole device for formation stress measurement, including: the packer comprises a first packer 10, a second packer 20 and a fracturing central rod 30, wherein the fracturing central rod 30 is connected between the first packer 10 and the second packer 20, and an inner cavity of the fracturing central rod 30, an inner cavity of the first packer 10 and an inner cavity of the second packer 20 are communicated; the fracturing central rod 30 is provided with a one-way adjusting switch 40, the one-way adjusting switch 40 comprises an adjusting component and a liquid outlet passage 43, the liquid outlet passage 43 penetrates through the side wall of the fracturing central rod 30, the adjusting component is arranged on the liquid outlet passage 43, the difference value between the pressure of the inner cavity of the fracturing central rod 30 and the pressure of the outer side is X, the adjusting component opens the liquid outlet passage 43 under the action of water pressure when the pressure X is larger than a pressure set value, and the adjusting component closes the liquid outlet passage 43 when the pressure X is smaller than or equal to the pressure.
It is noted that the pressure set point is a positive number and X may be a positive number, a negative number, or zero. If X is a positive number, it means that the pressure of the inner cavity of the fracturing center rod 30 is greater than the outside pressure, if X is a negative number, it means that the pressure of the inner cavity of the fracturing center rod 30 is less than the outside pressure, and if X is zero, it means that the pressure of the inner cavity of the fracturing center rod 30 is equal to the outside pressure.
For convenience, the inner cavity of the first packer 10 is referred to as a first inner cavity 11, the inner cavity of the second packer 20 is referred to as a second inner cavity 21, the inner cavity of the fracturing center rod 30 is referred to as a third inner cavity 31, the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 are communicated, and the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 together form the inner cavity of the ground stress measuring downhole device.
When the underground stress measuring downhole device is used in a hydrofracture underground stress measuring system, as shown in fig. 1, one of the first packer 10 and the second packer 20 is connected with a drill pipe 70, and the inner cavity of the first packer is communicated with the inner cavity of the drill pipe 70, the drill pipe 70 is connected with a high-pressure pump through a communication pipeline 80, the high-pressure pump feeds high-pressure water into the drill pipe 70 through the communication pipeline 80, and the water in the drill pipe 70 enters the underground stress measuring downhole device. For convenience of description, the first packer 10 will be described as being connected to the drill pipe 70. Further, after placing the downhole device for geostress measurement downhole, the first packer 10 is closer to the wellhead than the second packer 20. The first packer 10 and the second packer 20 each have an elastic portion made of an elastic material so that the first packer 10 and the second packer 20 will expand after water injection.
In specific application, the ground stress measuring downhole device provided by the embodiment can be applied to vertical downward or downward inclined drilling holes, is suitable for vertical upward or upward drilling holes, is particularly suitable for various axial drilling holes, and has the advantages of consistent application principle and consistent operation steps. For ease of description, the application of the geostress measuring downhole device to a vertically downward borehole as shown in FIG. 1 will be further described below.
In the process of carrying out the ground stress measurement, put into the position of awaiting measuring in the pit through drilling rod 70 with ground stress measurement downhole device, through drilling rod 70 to the water injection in the ground stress measurement downhole device, along with the water injection volume increases, first packer 10 and second packer 20 expand gradually to with the inner wall laminating of drilling, so that form the fracturing section between first packer 10 and the second packer 20, and the fracturing section is located between the inner wall of drilling and the outer wall of fracturing center rod 30, realize the setting promptly. Along with the continuous increase of water injection amount, the water pressure in the interior of the fracturing center rod 30 gradually rises, and when the difference value X between the inner cavity pressure and the outside pressure of the fracturing center rod 30 is greater than a pressure set value, the adjusting component opens the liquid outlet passage 43 under the action of the water pressure, so that water flows out to a fracturing section through the liquid outlet passage 43, the water pressure in the interior of the fracturing center rod 30 is always higher than the water pressure of the fracturing section in the process of injecting water to the fracturing section, and finally rock fracturing of the fracturing section is performed. After the rock in the fractured zone is fractured, the high pressure pump is shut off to stop supplying water to the drill rod 70, and water is drained when the fracture closure pressure tends to be stable. The above procedure was then repeated to complete the following refolding experiments.
The ground stress that this embodiment provided measures downhole device is more for being applicable to the higher condition of drilling water level, specifically, the drilling water level is higher and the distance between surface of water and the wellhead is shorter relatively promptly, and it is the same to transfer the height at ground stress measurement downhole device, and the drilling water level is higher, and then the water pressure that ground stress measurement downhole device received is bigger. In this case, when water is drained, the water pressure in the borehole at the position of the first packer 10 and the second packer 20 is relatively high due to the high water level of the borehole, and when the water supply to the drill pipe 70 is stopped, the water pressure in the borehole will cause the first packer 10 and the second packer 20 to contract, so that the water in the ground stress measurement downhole device is reversely pumped to the drill pipe 70, thereby achieving the water drainage operation.
As shown in fig. 1, in a preferred embodiment of this embodiment, two opposite ends of the liquid outlet passage 43 are respectively referred to as a first end and a second end, the first end is provided with a first opening 41, the second end is provided with a second opening 42, the adjusting assembly is disposed on the liquid outlet passage 43, the adjusting assembly includes a blocking piece 44 and an elastic resetting piece 45, the elastic resetting piece 45 is disposed between the blocking piece 44 and the second end, the blocking piece 44 can move along the liquid outlet passage 43, and the blocking piece 44 can block the first opening 41.
The axial direction of the liquid outlet channel 43 can be obliquely arranged with the axial direction of the fracturing central rod 30, and for the convenience of installation, the axial direction of the liquid outlet channel 43 is preferably perpendicular to the axial direction of the fracturing central rod 30.
In a preferred embodiment, the blocking member 44 is a ball bearing. The diameter of the ball is larger than the inner diameter of the first opening 41 so that the ball can be blocked at the first opening 41. The elastic restoring member 45 is used for providing a pushing force for the blocking member 44 so that the blocking member 44 abuts against the first end, and at the moment, the blocking member 44 blocks the first opening 41. The set pressure value is related to the elastic properties of the elastic return member 45.
The elastic restoring member 45 includes, but is not limited to, a spring, a rubber column, and other structures having elastic deformation performance. Preferably, the elastic return member 45 is a spring.
When the spring is selected for the elastic return element 45, the pressure set value is related to the material of the spring, the diameter of the spring itself, the diameter of the wire used for the spring, the axial length, and the initial compression. Changing any one or more of these factors can cause the pressure set point to change.
In a preferred embodiment, the one-way adjusting switch 40 further comprises a pressure adjusting member, at least a part of which is extended into the liquid outlet passage 43, and the pressure adjusting member is abutted against the elastic restoring member 45 for adjusting the initial compression amount of the elastic restoring member 45. In one case, the pressure regulating member is entirely located in the liquid outlet passage 43, and the position of the pressure regulating member within the liquid outlet passage 43 is adjustable. One end of the elastic resetting piece 45 is contacted with the blocking piece 44, the other end is contacted with the pressure adjusting piece, the position of the pressure adjusting piece in the liquid outlet passage 43 can be adjusted, when the position of the pressure adjusting piece is closer to the first end of the liquid outlet passage 43, the compression amount of the elastic resetting piece 45 is larger, and the pressure set value is correspondingly increased; when the pressure adjusting member is positioned closer to the second end of the liquid outlet passage 43, the compression amount of the elastic restoring member 45 is smaller, and the pressure set value is correspondingly reduced.
Or, in another embodiment, the pressure adjusting member only partially extends into the liquid outlet passage 43, and the longer the length of the pressure adjusting member extending into the liquid outlet passage 43 is, the larger the initial compression amount of the elastic restoring member 45 is, the larger the pressure required for opening the one-way adjusting switch 40 is, i.e. the larger the pressure setting value is. For example, the pressure adjusting member includes a hollow screw 46, the hollow screw 46 is disposed at the second end of the liquid outlet passage 43, a hollow cavity of the hollow screw 46 axially penetrates through the hollow screw 46, the hollow cavity is communicated with the second opening 42, and one end of the hollow screw 46 extends into the liquid outlet passage 43 from the second opening 42 and abuts against the elastic restoring member 45. The hollow screw 46 is connected with the inner wall of the liquid outlet channel in a threaded manner, and the length of the hollow screw 46 extending into the liquid outlet channel can be changed by screwing the hollow screw 46. The hollow cavity of the hollow screw 46 is communicated with the liquid outlet channel. After the one-way adjusting switch 40 is turned on, water enters the hollow cavity of the hollow screw 46 through the liquid outlet channel and flows from the hollow cavity to the outer side of the fracturing center rod 30.
In one possible embodiment, the one-way adjusting switch 40 may include a housing 47, the housing 47 is mounted on the fracturing center rod 30, the fluid outlet channel is formed in the housing 47, and the elastic component is mounted on the fluid outlet channel. With this arrangement, a through hole is provided in the fracturing center rod 30, and the housing 47 is mounted in the through hole. The sealing treatment is performed between the housing 47 and the inner wall of the through hole, specifically, a sealing ring is disposed or a glue seal is performed.
Alternatively, in another embodiment, the liquid outlet channel is directly formed on the side wall of the central fracturing rod 30, and the elastic component is mounted in the liquid outlet channel, so that the unidirectional adjusting switch 40 can be mounted in the central fracturing rod 30 without using the shell 47, and a sealing treatment is not needed.
At least one unidirectional adjusting switch 40 is arranged on the fracturing center rod 30, or a plurality of unidirectional adjusting switches 40 can be arranged.
When the fracturing center rod 30 is provided with the plurality of unidirectional adjusting switches 40, the plurality of unidirectional adjusting switches 40 may be irregularly distributed on the sidewall of the fracturing center rod 30, may also be distributed along the circumferential direction of the fracturing center rod 30, or may also be distributed along the axial direction of the fracturing center rod 30.
In the underground stress measuring device shown in fig. 1, a plurality of unidirectional adjusting switches 40 are arranged on the fracturing central rod 30, and the plurality of unidirectional adjusting switches 40 are distributed on the side wall of the fracturing central rod 30 at equal intervals along the axial direction of the fracturing central rod 30.
The pressure setting values of the plurality of unidirectional adjustment switches 40 may be the same or different, and preferably, the pressure setting values corresponding to the unidirectional adjustment switches 40 are different.
In a possible embodiment, the ground stress measuring downhole device further comprises a downhole pressure sensor 60, and the downhole pressure sensor 60 is mounted on the outer wall of the fracturing center rod 30 and is used for measuring the water pressure outside the fracturing center rod 30.
Further, sealing elements are arranged at the connection position of the first packer 10 and the drill rod 70, the connection position of the first packer 10 and the fracturing central rod 30, the connection position of the fracturing central rod 30 and the second packer 20, and the connection position of the second packer 20 and the choke plug 22. The sealing element can be a sealing ring.
The first packer 10 and the drill rod 70, the first packer 10 and the fracturing central rod 30, the fracturing central rod 30 and the second packer 20, and the second packer 20 and the plug 22 can be connected in a threaded manner.
Further, both ends at first packer 10 all are provided with first step face, and first step face includes two anchor ring faces that the diameter is different, and the external diameter of first anchor ring is greater than the internal diameter of second anchor ring, and the second anchor ring face is located one side that first anchor ring more is close to the terminal surface of first packer 10, or along the axial of first packer 10, and the second anchor ring face is located the outside of first anchor ring face. The first annulus is provided with threads to form a threaded section for connection and the second annulus is provided with a sealing ring.
Both ends of the second packer 20 are also provided with the same first step faces as described above.
One end of the fracturing center rod 30 is provided with a second step surface matched with the first step surface of the first packer 10, and a threaded hole is formed in the second step surface to be connected with the threaded section; the other end of the fracturing center end is provided with a second step surface matched with the first step surface of the second packer 20, and the second step surface is provided with a threaded hole to be connected with the threaded section.
Second embodiment
The underground stress measuring downhole device provided by the present embodiment is a modified version of the underground stress measuring downhole device provided by the first embodiment, and is different from the underground stress measuring downhole device provided by the first embodiment in that, as shown in fig. 4 to 9, the underground stress measuring downhole device provided by the present embodiment further includes a drain valve 50, and the drain valve 50 is connected to the first packer 10. The drain valve 50 is used for draining the communicated inner cavities of the first packer 10, the fracturing central rod 30 and the second packer 20. Other structures of the ground stress measurement downhole device provided in this embodiment are the same as the corresponding structures in the first embodiment, and are not described herein again.
The ground stress measurement downhole device provided by the embodiment can be suitable for a drilling well with a high drilling water level, but compared with the ground stress measurement downhole device provided by the first embodiment, the ground stress measurement downhole device provided by the embodiment is more suitable for a drilling well with a shallow drilling water level or a dry hole, in the drilling well, the distance from the water surface to the wellhead is longer, and when the lowering height of the ground stress measurement downhole device is the same, the drilling water level is shallower, so that the ground stress measurement downhole device is subjected to smaller external water pressure. After fracturing the rock of the borehole using the geostress measuring downhole device, water is drained from the internal cavity of the geostress measuring downhole device through a drain valve 50.
The following embodiments can be used for the water escape valve 50 provided in this example: the drain valve 50 comprises a valve body 52 and a valve core rod 51, wherein the valve body 52 is connected with the first packer 10, one end of the valve core rod 51 extends into an inner cavity of the valve body 52, the other end of the valve core rod 51 is used for being connected with the drill rod 70, and the valve core rod 51 can move relative to the inner cavity of the valve body 52 to move between a first position and a second position; the valve body 52 comprises a transit waterway 521 and a drainage port 522, and the transit waterway 521 is communicated with an inner cavity of the first packer 10; the valve core rod 51 is provided with a water inlet passage 511, the water inlet passage 511 is provided with a first water passing port 512 and a second water passing port 513, the first water passing port 512 is used for being communicated with a transit waterway 521, and the second water passing port 513 is used for being communicated with a water drainage port 522; in the first position, the first water passing port 512 is communicated with the transfer water path 521, while the second water passing port 513 is blocked by the inner wall of the valve body 52, and since the first water passing port 512 is communicated with the second water passing port 513, the water entering the second water passing port 513 finally flows into the transfer water path 521 through the first water passing port 512. In the second position, the second water passing opening 513 is communicated with the drain opening 522, the first water passing opening 512 is blocked by the inner wall of the valve body, and water entering the first water passing opening 512 finally flows into the drain opening 522 from the second water passing opening 513.
As shown in fig. 5 and 6, in the water injection process, the valve core rod 51 is located at the first position, the first water passing port 512 is opposite to the transit waterway 521, the first water passing port 512 is communicated with the transit waterway 521, and the water injected into the drill rod 70 enters the water inlet passage 511 of the valve core rod 51, enters the transit waterway 521 through the first water inlet, and finally enters the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 through the transit waterway 521.
As shown in fig. 7 and 8, in the draining process, the valve core rod 51 is first moved to the second position, so that the second water drainage port 513 is communicated with the water drainage port 522, and the water in the drill rod 70 is drained through the water drainage port 522, so that the water amount in the inner cavity of the valve core rod 51 and the drill rod 70 gradually drops. After the water in the drill rod 70 and the inner cavity of the valve core rod 51 is completely or nearly completely discharged, the valve core rod 51 is moved to the first position, so that the first waterway of the valve core rod 51 is communicated with the transfer waterway 521, the water pressure in the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 is high, the pressure of the inner cavity of the drill rod 70 and the inner cavity of the valve core rod 51 is low, and therefore the water in the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 enters the inner cavity of the valve core rod 51 and the inner cavity of the drill rod 70 from the first water inlet via the transfer waterway 521, so that the water drainage operation of the first inner cavity 11, the second inner cavity 21 and the third inner cavity 31 is realized, and the first packer 10 and the second packer 20 are contracted.
Further, as shown in fig. 6, in a preferred embodiment, a pressure relief opening 525 is further provided on the side wall of the valve body 52, one end of the valve body 52 extends into the valve core rod 51, and the pressure relief opening 525 is provided on the side wall of the valve body 52 near the other end. For example, the top end of the valve body 52 is used to extend into the valve core rod 51, the pressure relief opening 525 is disposed on the side wall of the valve body 52 near the bottom end, and the distance between the pressure relief opening 525 and the top end of the valve body 52 is greater than the distance between the drain opening 522 and the top end of the valve body 52.
As shown in fig. 9, a plurality of ring grooves are provided in the valve body 52, a first seal ring 54 is provided in a part of the ring grooves, and a second seal ring 55 is provided in a part of the ring grooves. Specifically, taking the direction shown in fig. 9 as an example, when the valve body 52 of the relief valve is placed in the vertical direction in the axial direction, the number of the first sealing rings 54 is plural, and at least one first sealing ring 54 is provided on each of the upper and lower sides of the opening of the transfer water path 521 for communicating with the first water passing port 512. The number of the second sealing rings 55 is plural, and at least one second sealing ring 55 is respectively provided on the upper and lower sides of the drain opening 522.
In fig. 9, the number of the first sealing rings 54 and the second sealing rings 55 is two, one first sealing ring 54 is provided on each of the upper and lower sides of the opening of the relay water passage 521 for communicating with the first water passing port 512, and one second sealing ring 55 is provided on each of the upper and lower sides of the water discharge port 522. After the valve core rod 51 is inserted into the valve body 52, when the valve core rod 51 is located at the first position, the first sealing ring 54 is located between the valve core rod 51 and the valve body 52, and the first water passing port 512 is communicated with the transfer water channel 521, and meanwhile, the valve core rod 51 and the valve body 52 are sealed, so that water is prevented from flowing into positions except the transfer water channel 521 through a gap between the valve core rod 51 and the valve body 52. When the valve core rod 51 is located at the second position, the second seal ring 55 is located between the valve core rod 51 and the valve body 52, and seals the valve core rod 51 and the valve body 52 while ensuring communication between the second water drainage port 513 and the water drainage port 522, thereby preventing water from flowing into positions other than the water drainage port 522 through a gap between the valve core rod 51 and the valve body 52.
In order to limit the valve core rod 51 conveniently, the valve core rod 51 is a variable diameter rod, and comprises a first section with a smaller outer diameter and a second section with a larger outer diameter, and the first section and the second end are integrally formed into an integral structure. The second section is located entirely within the valve body 52 with a portion of the first section extending into the interior of the valve body 52 and the first section being connected to the drill stem 70. The aperture of the opening of the valve body 52 for extending into the drill rod 70 is slightly larger than the outer diameter of the first section and smaller than the outer diameter of the second section, so that the valve core rod 51 can be limited.
In order to facilitate assembly of the valve body 52 and the valve core rod 51, the valve body 52 comprises a first valve body 523 and a second valve body 524, the first valve body 523 and the second valve body 524 both have inner cavities, the inner cavities of the first valve body 523 and the second valve body 524 are communicated after the first valve body 523 and the second valve body 524 are connected to form a fourth cavity 53 for movement of the valve core rod 51, and an opening for the valve core rod 51 to extend into is arranged at one end of the first valve body 523 away from the second valve body 524. The drain opening 522 and the relief opening 525 are both provided in the side wall of the second valve body 524. The first valve body 523 is connected to the second valve body 524 by screw threads, and a sealing member is disposed at the connection. The connection structure between the first valve body 523 and the second valve body 524, and the connection structure between the second valve body 524 and the first packer 10 can refer to the connection structure between the first packer 10 and the fracturing central rod 30 in the first embodiment described above. So configured, during assembly, the first section of the valve core rod 51 is extended from the inner cavity of the first valve body 523 to be opened, so that part of the first section is extended out of the first valve body 523, and at least part of the second section is located in the inner cavity of the first valve body 523, and then the second valve body 524 is connected with the first valve body 523.
When the underground stress measurement downhole device provided by the embodiment is applied to a vertical downward well, in the process of lowering the underground stress measurement downhole device, the valve body 52 is downward under the influence of gravity, so that the second section is abutted against the top of the valve body 52, the position is a first position, and at the moment, the first water passing port 512 of the valve core rod 51 is communicated with the transit waterway 521. When water drainage is needed subsequently, because the flushing expansion in the first packer 10 is relatively fixed with the side wall of the drilled well, the valve core rod 51 is pressed downwards through the drill rod 70, the valve body 52 is connected with the first packer 10, the position of the valve body 52 is not changed, the valve core rod 51 moves downwards relative to the valve body 52, and therefore the valve core rod 51 can move to the second position, and the second water drainage port 513 can be communicated with the water drainage port 522.
To facilitate determination of the specific position of the second position, the position at which the spool rod 51 is moved into contact with the bottom of the valve body 52 may be made the second position, or a stopper may be provided inside the valve body 52, indicating that the spool rod 51 has reached the second position when it is in contact with the stopper.
Third embodiment
As shown in fig. 2 and 4, a hydraulic fracturing ground stress measuring system comprises a drill pipe 70, a high-pressure pump and the ground stress measuring downhole device provided by the first embodiment or the second embodiment, wherein the high-pressure pump is used for injecting water into the ground stress measuring downhole device through the drill pipe 70.
Specifically, water is injected into the inner cavity of the drill stem 70 through the communication pipeline 80 between the high-pressure pump and the drill stem 70, the inner cavity of the drill stem 70 is communicated with the inner cavity of the first packer 10 of the ground stress measurement downhole device, and the inner cavity of the first packer 10, the inner cavity of the fracturing central rod 30 and the inner cavity of the second packer 20 form the inner cavity of the ground stress measurement downhole device due to the fact that the inner cavity of the first packer 10, the inner cavity of the fracturing central rod 30 and the inner cavity of the second packer 20 are communicated, and therefore water can be injected into the inner cavity of the ground stress measurement downhole device through the drill stem 70.
Since the hydraulic fracturing ground stress measuring system provided by the embodiment applies the ground stress measuring downhole device provided by the first embodiment or the second embodiment, the hydraulic fracturing ground stress measuring system has at least the following advantages:
the one-way adjusting switch 40 arranged on the fracturing center rod 30 is used for replacing a push-pull valve in the prior art, the one-way adjusting switch 40 automatically performs switching operation by sensing water pressure, manual operation is not needed, operation steps in an experimental process are reduced, operation difficulty is reduced, and the problem that a seal seat of the push-pull valve is easily abraded and leaks is solved.
The position of the one-way adjusting switch 40 is skillfully arranged, the structure is simple and easy to realize, the structure of the whole device is simple, and the cost is reduced.
The inner cavities of the first packer 10, the second packer 20 and the fracturing center rod 30 are communicated, namely the three are in the same water path, when the water release valve 50 is not arranged, the whole device is not afraid of blockage of mud and sundries, even if a small part of mud and sundries enter, the first packer 10 and the second packer 20 can sink, and the one-way adjusting switch 40 on the fracturing center rod 30 cannot be blocked.
The underground stress measuring device is suitable for various axial drilling holes, so that the application range of the hydraulic fracturing underground stress measuring system is wider.
When the drain valve 50 is not arranged, the system does not have a thin position, the strength of the whole system is high, and the whole system cannot be easily pulled or crushed by high-pressure water. And the inner water flow channel has no thinner position and can not be easily blocked.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A ground stress measurement downhole device, comprising: the packer comprises a first packer, a second packer and a fracturing center rod, wherein the fracturing center rod is connected between the first packer and the second packer, and an inner cavity of the fracturing center rod, an inner cavity of the first packer and an inner cavity of the second packer are communicated;
the fracturing center rod is provided with a one-way adjusting switch, the one-way adjusting switch comprises an adjusting component and a liquid outlet passage, the liquid outlet passage penetrates through the side wall of the fracturing center rod, the adjusting component is arranged on the liquid outlet passage, the difference value between the pressure of an inner cavity of the fracturing center rod and the pressure of the outer side is X, the adjusting component opens the liquid outlet passage under the action of water pressure when the X is larger than a pressure set value, and the adjusting component closes the liquid outlet passage when the X is smaller than or equal to the pressure set value.
2. The ground stress measurement downhole device according to claim 1, wherein the opposite ends of the liquid outlet passage are divided into a first end and a second end, the first end is provided with a first opening, the second end is provided with a second opening, the adjusting assembly is arranged on the liquid outlet passage, the adjusting assembly comprises a blocking piece and an elastic resetting piece, the elastic resetting piece is arranged between the blocking piece and the second end, the blocking piece can move along the liquid outlet passage, and the blocking piece can block the first opening.
3. A ground stress measuring downhole device according to claim 2, wherein the blocking element is a ball and/or the resilient return element is a spring.
4. The ground stress measurement downhole device of claim 2, wherein the one-way adjustment switch further comprises a pressure adjustment member, at least a part of the structure of the pressure adjustment member extends into the liquid outlet passage, and the pressure adjustment member abuts against the elastic reset member for adjusting the initial compression amount of the elastic reset member.
5. The ground stress measurement downhole device according to claim 4, wherein the pressure adjusting member comprises a hollow screw, the hollow screw is disposed at the second end of the liquid outlet passage, a hollow cavity of the hollow screw axially penetrates through the hollow screw, the hollow cavity is communicated with the second opening, and one end of the hollow screw extends into the liquid outlet passage from the second opening and abuts against the elastic restoring member.
6. The underground stress measuring device according to any one of claims 2 to 5, wherein the sidewall of the fracturing center rod is provided with a plurality of the unidirectional adjusting switches, and the unidirectional adjusting switches have different pressure setting values.
7. The ground stress measurement downhole device of claim 1, further comprising a drain valve connected to the first packer.
8. The ground stress measurement downhole device of claim 7, wherein the drain valve comprises a valve body and a valve core rod, the valve body is connected with the first packer, one end of the valve core rod extends into the inner cavity of the valve body, the other end is used for being connected with a drill rod, and the valve core rod can move relative to the inner cavity of the valve body to move between a first position and a second position; the valve body comprises a transfer waterway and a water discharge opening, and the transfer waterway is communicated with an inner cavity of the first packer; the valve core rod is provided with a water inlet passage, and the water inlet passage is provided with a first water passing port and a second water passing port; in the first position, the first water passing port is communicated with a transfer waterway; and in the second position, the second water passing opening is communicated with the water drainage opening.
9. The ground stress measurement downhole device of claim 1, further comprising a downhole pressure sensor mounted to an outer wall of the frac center rod.
10. A hydrofracturing ground stress measurement system comprising a drill string, a high pressure pump for injecting water through the drill string into the ground stress measurement downhole device, and the ground stress measurement downhole device of any one of claims 1-9.
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| CN202110100194.2A CN112814638A (en) | 2021-01-26 | 2021-01-26 | Ground stress measuring downhole device and hydraulic fracturing ground stress measuring system |
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| CN202110100194.2A CN112814638A (en) | 2021-01-26 | 2021-01-26 | Ground stress measuring downhole device and hydraulic fracturing ground stress measuring system |
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| CN113309514A (en) * | 2021-07-09 | 2021-08-27 | 中国地质科学院地质力学研究所 | Ground stress measuring device for horizontal hole |
| CN114033326A (en) * | 2021-11-02 | 2022-02-11 | 中国矿业大学 | Push rod mounting and dismounting device and method for ground stress test |
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| CN114033326B (en) * | 2021-11-02 | 2023-10-31 | 中国矿业大学 | Push rod mounting and dismounting device and method for ground stress test |
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