CN114396249B - Coal stratum hydraulic fracturing pressure monitoring device, effect evaluation and fault analysis method - Google Patents
Coal stratum hydraulic fracturing pressure monitoring device, effect evaluation and fault analysis method Download PDFInfo
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- CN114396249B CN114396249B CN202111550919.4A CN202111550919A CN114396249B CN 114396249 B CN114396249 B CN 114396249B CN 202111550919 A CN202111550919 A CN 202111550919A CN 114396249 B CN114396249 B CN 114396249B
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- 239000003245 coal Substances 0.000 title claims abstract description 23
- 230000000694 effects Effects 0.000 title claims abstract description 21
- 238000004458 analytical method Methods 0.000 title claims abstract description 14
- 238000012806 monitoring device Methods 0.000 title claims abstract description 13
- 238000011156 evaluation Methods 0.000 title abstract description 8
- 238000007789 sealing Methods 0.000 claims abstract description 179
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 92
- 239000002775 capsule Substances 0.000 claims abstract description 88
- 238000005336 cracking Methods 0.000 claims abstract description 59
- 230000000007 visual effect Effects 0.000 claims abstract description 32
- 239000000523 sample Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 21
- 238000002347 injection Methods 0.000 claims abstract description 15
- 239000007924 injection Substances 0.000 claims abstract description 15
- 230000007246 mechanism Effects 0.000 claims description 54
- 238000004891 communication Methods 0.000 claims description 27
- 239000011435 rock Substances 0.000 claims description 24
- 238000004140 cleaning Methods 0.000 claims description 22
- 238000012544 monitoring process Methods 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 14
- 239000010959 steel Substances 0.000 claims description 14
- 230000035515 penetration Effects 0.000 claims description 11
- 230000000149 penetrating effect Effects 0.000 claims description 9
- 230000002093 peripheral effect Effects 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 9
- 238000005553 drilling Methods 0.000 claims description 7
- WSNMPAVSZJSIMT-UHFFFAOYSA-N COc1c(C)c2COC(=O)c2c(O)c1CC(O)C1(C)CCC(=O)O1 Chemical compound COc1c(C)c2COC(=O)c2c(O)c1CC(O)C1(C)CCC(=O)O1 WSNMPAVSZJSIMT-UHFFFAOYSA-N 0.000 claims description 4
- 238000009792 diffusion process Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 238000005516 engineering process Methods 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
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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
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/1208—Packers; Plugs characterised by the construction of the sealing or packing means
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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
- E21B47/00—Survey of boreholes or wells
- E21B47/002—Survey of boreholes or wells by visual inspection
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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
- E21B47/00—Survey of boreholes or wells
- E21B47/06—Measuring temperature or pressure
-
- 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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- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
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- Examining Or Testing Airtightness (AREA)
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Abstract
The hydraulic fracturing pressure monitoring device for the coal stratum, the effect evaluation and the fault analysis method are characterized in that an annular limiting groove A is formed in the outer part of the middle section of a rod body at the front end of the device, and a front rubber hole sealing capsule sleeve is sleeved on the annular limiting groove A; the rear end of the front rod body is provided with a front hole sealing male connector; the rear end of the probe mounting rod is fixedly inserted into an axial through hole I at the left end of the front rod body, and a visual camera is arranged in the center of the front end of the probe mounting rod; the front end and the rear end of the middle rod body are respectively provided with a fracturing section front end female connector and a fracturing section rear end female connector; an annular limiting groove B is formed in the outer part of the middle section of the rear end rod body, and a rear rubber hole sealing capsule is sleeved on the annular limiting groove B; the front end of the rear rod body is provided with a rear hole sealing front male connector. The method comprises the following steps: assembling a hole packer; observing the image to determine a pressure cracking point; injecting water to seal holes, and then fracturing; stopping water injection; and performing effect evaluation and fault analysis according to the acquired data. The device and the method can be used for conveniently judging whether the fracturing position is reasonable, are helpful for analyzing the fault reasons and are helpful for quantifying the cracking pressure.
Description
Technical Field
The invention belongs to the technical field of hydraulic fracturing, and particularly relates to a coal stratum hydraulic fracturing pressure monitoring device, an effect evaluation and fault analysis method.
Background
The hydraulic fracturing technology is a reservoir reconstruction technology widely applied in the field of oil and gas development, and is popularized and applied in the fields of pressure relief, permeability improvement, deep original rock ground stress measurement and the like of a coal mine. At present, the hydraulic fracturing technology is relatively mature in the field of coal exploitation, and has many successful cases and practical experience aiming at the aspects of ground subsidence, coal seam permeability improvement, hard rock roof cutting, controlled pressure relief and the like. The main action principle is that a hydraulic fracturing hole packer is used for packing a section in a drill hole to serve as a fracturing section, and high-pressure fluid is injected into the fracturing section to crack rock on the hole wall and expand the crack outwards to form a fracture network.
In the prior art, the hydraulic fracturing hole packer used in the underground coal mine mainly has the following defects: (1) The position of the fracturing stratum can be determined only by means of a drilling histogram of early geological survey, and the rationality of the fracturing position cannot be evaluated in the early stage; (2) problems with equipment cannot be addressed, for example: in the hydraulic fracturing process, the visual phenomenon cannot determine whether the equipment has a problem or the specific position of the problem, and a great amount of time is still required to be consumed after the equipment is retracted to check the reason of the problem; (3) The existing hole packer integrating fracturing and hole sealing has the defects that the design error of fracturing water outlet pressure control is too large, the cracking pressure of a hole sealing section cannot be quantized, uncertainty exists, and a definite data standard cannot be given.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a coal stratum hydraulic fracturing pressure monitoring device, an effect evaluation and a fault analysis method, which can be used for conveniently pre-judging whether the fracturing position is reasonable in the early stage, is beneficial to quickly analyzing the failure cause after the failure occurs, and is also beneficial to quantifying the fracturing pressure of a hole sealing section; the method has simple steps, is favorable for reasonably evaluating the fracturing effect, can comprehensively analyze after faults occur, and is convenient for quickly determining the fault reasons.
In order to achieve the aim, the invention provides a coal stratum hydraulic fracturing pressure monitoring device which comprises a front hole sealing mechanism, a middle section fracturing mechanism and a rear hole packer mechanism;
the front hole sealing mechanism mainly comprises a front end rod body, a probe mounting rod, a front rubber hole sealing capsule, a visual camera and a camera protection cover; the axle center of the front end rod body is provided with an axial through hole I which is axially communicated; an annular limiting groove A is formed in the outer portion of the middle section of the front-end rod body, a radial communication hole I which is communicated with the axial through hole I and the outer space of the front-end rod body is formed in the middle of the annular limiting groove A, and a capsule electromagnetic valve I which is used for controlling the on-off of the radial communication hole I is arranged in the radial communication hole I; the rear end of the front end rod body is provided with a first annular concave table, the outer diameter of the first annular concave table is smaller than that of the front end rod body, and the outer surface of the first annular concave table is provided with a first external thread structure to form a front hole sealing male joint; the rear end of the axial through hole I is connected with a pressure sensor III and a flowmeter III; the pressure sensor III and the flowmeter III are respectively used for monitoring pressure signals and flow signals in the axial through hole I in real time; the outer diameter of the probe mounting rod is smaller than that of the front rod body, and the rear end of the probe mounting rod is fixedly inserted into the axial through hole I at the left end of the front rod body; the center of the front end of the probe mounting rod is provided with a camera mounting groove, the outer side of the camera mounting groove is provided with an axial channel I, the axial channel I axially penetrates through the front end and the rear end of the probe mounting rod, the right end of the probe mounting rod is also communicated with the axial through hole I, and the middle part of the probe mounting rod is provided with a cleaning electromagnetic valve for opening or closing the axial channel I; the front rubber hole sealing capsule is sleeved in the annular limiting groove A, the front end and the rear end of the front rubber hole sealing capsule are fixedly connected with the front end and the rear end of the annular limiting groove A respectively, and a hole packer sealing space I is formed between the front rubber hole sealing capsule and the front end rod body and is communicated with the axial through hole I through a radial communication hole I; the first hole packer sealing space is connected with a pressure sensor A; a visual camera is arranged in the camera mounting groove; the camera protective cover is packaged at the opening end of the camera mounting groove;
The middle section fracturing mechanism mainly comprises a middle section rod body and a fracturing electromagnetic valve, wherein an axial through hole II which is axially communicated is formed in the axis of the middle section rod body, an annular containing cavity I and an annular containing cavity II are respectively formed in the center of the front end and the center of the rear end of the middle section rod body, a plurality of fracturing channels are radially formed in the middle section of the middle section fracturing mechanism, the inner end of each fracturing channel is communicated with the axial through hole II, the outer end of each fracturing channel is communicated with the outside of the middle section rod body, a pressure sensor IV and a flow meter IV are connected to the middle section of the middle section fracturing mechanism, and the pressure sensor IV and the flow meter IV are respectively used for monitoring pressure signals and flow signals in the fracturing channels in real time; the number of the fracturing electromagnetic valves corresponds to the number of the fracturing channels, and the fracturing electromagnetic valves are assembled in the middle of the fracturing channels and used for controlling the on-off of the fracturing channels; the size of the annular accommodating cavity I is matched with the size of the annular concave table I, an internal thread structure I matched with the external thread structure I is arranged on the inner surface of the annular accommodating cavity I, and a female joint at the front end of the fracturing section is formed; an internal thread structure II is arranged in the annular accommodating cavity II, and a female joint at the rear end of the fracturing section is formed; the front end of the middle section fracturing mechanism is fixedly connected with the rear end of the front hole sealing mechanism through the threaded fit of the front end female joint of the fracturing section and the front hole sealing male joint;
The rear hole packer mechanism mainly comprises a rear end rod body and a rear rubber hole sealing capsule; the axle center of the rear end rod body is provided with an axial through hole III which is axially communicated; an annular limiting groove B is formed in the outer portion of the middle section of the rear end rod body, a radial communication hole II which is communicated with the axial through hole III and the outer space of the rear end rod body is formed in the middle of the annular limiting groove B, and a capsule electromagnetic valve II which is used for controlling the on-off of the radial communication hole II is arranged in the radial communication hole II; the front end of the rear end rod body is provided with a second annular concave table, the outer diameter of the second annular concave table is smaller than that of the rear end rod body, the size of the second annular concave table is matched with that of the second annular accommodating cavity, the outer surface of the second annular concave table is provided with a second external thread structure, and a front end male joint of the rear hole sealing is formed; the front end of the rear hole packer mechanism is fixedly connected with the middle section fracturing mechanism through the threaded fit of the front male connector of the rear hole packer and the rear female connector of the fracturing section; the rear rubber hole sealing capsule is sleeved in the annular limiting groove B, the front end and the rear end of the rear rubber hole sealing capsule are fixedly connected with the front end and the rear end of the annular limiting groove B respectively, a hole packer sealing space II is formed between the rear rubber hole sealing capsule and the rear end rod body, and the hole packer sealing space II is communicated with the axial through hole III through a radial communication hole II; the second sealing space of the hole packer is connected with a pressure sensor B; the part of the axial through hole III, which is positioned in front of the annular limiting groove B, is connected with a pressure sensor II and a flowmeter II; the second pressure sensor and the second flowmeter are respectively used for monitoring pressure signals and flow signals of the front end of the axial through hole III; the part of the axial through hole III behind the annular limiting groove B is connected with a pressure sensor I and a flowmeter I; the first pressure sensor and the first flowmeter are respectively used for monitoring pressure signals and flow signals of the three rear ends of the axial through holes.
Further, in order to improve the cleaning effect on the lens and obtain clearer image data, the number of the first axial channels is two, the first axial channels are respectively provided with a cleaning electromagnetic valve, and the cleaning electromagnetic valves are oppositely distributed on two opposite sides of the camera mounting groove.
Further, in order to facilitate connection and separation of the high-pressure water injection steel pipe, the rear end of the rear end rod body is provided with an annular concave third, the outer diameter of the annular concave third is smaller than that of the rear end rod body, the outer surface of the annular concave third is provided with an external thread structure third, and a rear end male connector for rear hole sealing is formed.
Preferably, the camera mounting groove is cylindrical.
Preferably, the outer diameters of the front end rod body, the middle rod body and the rear end rod body are the same.
In the technical scheme, by arranging the visual camera at the front end of the front end rod body, a real-time image transmitted by the front end camera in the pushing process can be observed whether the designed cracking position surrounding rock is complete or not, and whether the hole wall is smooth or not, so that whether the current cracking point meets the required standard or not can be reasonably judged; through the arrangement of the pressure sensor IV and the flow meter IV, the pressure signal and the flow signal in the fracturing channel can be monitored in real time, so that the cracking pressure of the hole sealing section can be quantified conveniently. The pressure sensor A and the pressure sensor B are respectively arranged in the first sealing space and the second sealing space of the hole packer, so that the pressure value of the sealing space of the hole packer can be conveniently collected in real time; the pressure sensor III and the flowmeter III are connected to the rear end of the axial through hole I, the pressure sensor II and the flowmeter II are arranged at the front end of the axial through hole III, and the pressure sensor I and the flowmeter I are arranged at the rear end of the axial through hole I, so that analysis of fault reasons can be conveniently carried out after faults occur, and the fault position can be rapidly determined.
The invention also provides a coal stratum hydraulic fracturing pressure effect evaluation and fault analysis method, which comprises a coal stratum hydraulic fracturing pressure monitoring device, and further comprises the following steps:
step one: firstly, reliably connecting a front end female connector of a fracturing section and a rear end female connector of the fracturing section of a middle-section fracturing mechanism with a front hole sealing male connector of a front hole sealing mechanism and a rear hole sealing front end male connector of a rear hole sealing mechanism through threads, and forming a hole sealing device; establishing communication connection between the cleaning electromagnetic valve, the fracturing electromagnetic valve, the capsule electromagnetic valve I, the capsule electromagnetic valve II, the visual camera, the pressure sensor A, the pressure sensor B, the pressure sensor IV, the flow meter IV, the pressure sensor III, the flow meter III, the pressure sensor II, the flow meter II, the pressure sensor I and the flow meter I and the control terminal, and checking whether each monitoring terminal operates normally; finally, a rear male joint of the rear hole sealing of the rear hole packer mechanism is connected with a high-pressure water injection steel pipe, and the hole packer is sent into the fracturing hole by a drilling machine;
step two: in the pushing process of the hole packer in the fracturing hole, image data are acquired in real time through a visual camera so as to observe the structural characteristics of the surrounding rock of the fracturing hole in real time;
Step three: when the hole packer is pushed to the vicinity of the cracking point, the visual camera at the front end is used for collecting image data in real time, observing whether the designed cracking position surrounding rock is complete or not and whether the hole wall is smooth or not, and if the cracking point position designed according to the drilling histogram does not meet the cracking point standard, continuously searching for a proper cracking point;
step four: after the hole packer reaches the position of a cracking point, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be opened, a high-pressure water pump is started to inject high-pressure water into the first hole packer sealing space and the second hole packer sealing space by utilizing a high-pressure water injection steel pipe, pressure signals in the first hole packer sealing space and the second hole packer sealing space are monitored in real time through pressure sensors A and B, when the pressure in the first hole packer sealing space and the second hole packer sealing space reaches the designed hole sealing pressure, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be closed, the fracturing electromagnetic valve is controlled to be opened, and the high-pressure water is supplied into the sealing space between the first hole packer sealing space and the second hole packer sealing space until the cracking point rock stratum is cracked by the high-pressure water;
step five: turning off the high-pressure water pump, continuing to advance to the next designed cracking point after the front rubber hole sealing capsule and the rear rubber hole sealing capsule are restored to the original state, and repeating the second to fourth steps;
Step six: during the process of pushing the hole packer and withdrawing the hole packer, acquiring and recording image data in real time through a visual camera, acquiring and recording pressure signals and flow signal data in real time through a pressure sensor IV, a flow meter IV, a pressure sensor A, a pressure sensor B, a pressure sensor III, a flow meter III, a pressure sensor II, a flow meter II, a pressure sensor I and a flow meter I, and evaluating fracturing effects according to the recorded data;
if a fault occurs, the analysis is performed by the following method:
s1: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, and after the high-pressure water is injected for a period of time, the cracking hole starts to discharge a large amount of water, so that the following four possibilities exist: i. the high-pressure water pressure is too high, so that the front rubber hole sealing capsule is damaged and the fracturing fails; ii. The high-pressure water is excessively high, so that the rear rubber hole sealing capsule is damaged and the fracturing fails; iii, the front rubber hole sealing capsule and the rear rubber hole sealing capsule are complete, the closed space is complete, only the peripheral rock mass of the fracturing point rock stratum is fractured, the extension degree of the fracture to the deep part is low, and the penetration degree of the fracture of the peripheral rock mass of the sealed space is large; iv, the hole packer is complete, gaps exist between the front rubber hole sealing capsule and the rear rubber hole sealing capsule and hole wall fracturing, and the sealing effect is poor;
For the ith condition, analyzing according to the recorded results of the first pressure sensor, the first flowmeter, the second pressure sensor and the second flowmeter, if the flow values of the first flowmeter and the second flowmeter are unequal, and the pressure values of the third pressure sensor and the second pressure sensor are lower than the set hole sealing pressure, determining that the front rubber hole sealing capsule is damaged, so that the water outlet phenomenon of the fracturing hole is caused;
in the ii-th case, analyzing according to the recorded results of the first pressure sensor, the first flow meter, the second pressure sensor, the second flow meter, the third pressure sensor and the third flow meter, if the flow values of the first flow meter, the second flow meter and the third flow meter are equal, and the pressure values of the third pressure sensor, the second pressure sensor and the third pressure sensor are equal and lower than the set hole sealing pressure, determining that the rear rubber hole sealing capsule is broken, and causing the water outlet phenomenon of the fracturing hole;
for the iii and iv cases, analyzing according to the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor, if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor and the flow value of the second pressure sensor are equal, water marks around the hole wall are observed by using real-time images acquired by a visual camera, and if the water marks on the hole wall are large in diffusion degree, gaps exist between the front rubber hole sealing capsule or the rear rubber hole sealing capsule and the hole wall, so that the water phenomenon of a cracking hole is caused; if no obvious water trace exists around the hole wall, more through cracks are formed near the cracking point, and the cracking degree is high, the phenomenon that the through cracks are formed around the cracking point to lead the cracking hole to discharge water can be determined;
S2: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, after the high-pressure water is injected for a period of time, the inside of the cracking hole does not produce water, and the peripheral holes also have no water, so that the following two possibilities are provided: i. the high-pressure water pump is damaged and cannot continuously boost pressure; ii. The fracture crack is more penetrating, and is penetrated again with the original penetrating crack around the fracture hole, and the high-pressure water flows to the deep part along the penetrating crack;
for the ith condition, analyzing according to the record structures of the first pressure sensor and the first flowmeter, if the flow value of the first flowmeter is unchanged for a long time, the pressure value of the first pressure sensor is always constant and the pressure is lower, and determining that the high-pressure water pump is damaged;
in the ii-th case, the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor are analyzed, and if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor is equal to the flow value of the second pressure sensor, the phenomenon that the fracture penetration degree is larger, the fracture penetration degree is penetrated with the original through fracture around the fracturing hole again, and high-pressure water flows to the deep part along the through fracture can be determined.
Preferably, in the second step, if the front end of the lens of the visual camera is found to be blurred and covered by dirt, the cleaning electromagnetic valve is controlled to be opened so as to automatically clean the lens of the visual camera, and after the cleaning is completed, the cleaning electromagnetic valve is controlled to be closed and the forward pushing is continued.
The method has simple steps, can collect front-end image data and pressure and flow data of key parts in real time, is favorable for reasonably evaluating the fracturing effect, can comprehensively analyze after faults occur, and is convenient for quickly determining the fault reasons.
Drawings
FIG. 1 is a schematic diagram of a front sealing mechanism in the present invention;
FIG. 2 is a schematic view of a middle stage fracturing mechanism in the present invention;
fig. 3 is a schematic structural view of the back packer mechanism of the present invention.
In the figure: 1. front hole sealing mechanism, 2, middle section fracturing mechanism, 3, back hole sealing mechanism, 4, front end rod body, 5, probe mounting rod, 6, front rubber hole sealing capsule, 7, visual camera, 8, camera protective cover, 9, axial through hole I, 10, annular concave table I, 11, external thread structure I, 12, cleaning electromagnetic valve, 13, middle section rod body, 14, annular limit groove B,15, axial through hole II, 16, annular accommodating chambers I, 17, annular accommodating chambers II, 18, fracturing channels, 19, fracturing solenoid valves, 20, first internal screw thread structures, 21, second internal screw thread structures, 22, rear end rod bodies, 23, rear rubber hole sealing capsules, 24, third axial through holes, 25, second annular concave platforms, 26, third annular concave platforms, 27, second external screw thread structures, 28, third external screw thread structures, 29, first axial channels, 30 and annular limiting grooves A.
Detailed Description
The present invention will be further described below.
As shown in fig. 1 to 3, the invention provides a coal stratum hydraulic fracturing pressure monitoring device, which comprises a front hole sealing mechanism 1, a middle stage fracturing mechanism 2 and a rear hole packer mechanism 3;
the front hole sealing mechanism 1 mainly comprises a front end rod body 4, a probe mounting rod 5, a front rubber hole sealing capsule 6, a visual camera 7 and a camera protection cover 8; the axle center of the front end rod body 4 is provided with an axial through hole I9 which is axially communicated; an annular limiting groove A30 is formed in the outer part of the middle section of the front end rod body 4, a radial communication hole I which is communicated with the axial through hole I9 and the outer space of the front end rod body 4 is formed in the middle of the annular limiting groove A30, and a capsule electromagnetic valve I which is used for controlling the on-off of the radial communication hole I is arranged in the radial communication hole I; the rear end of the front end rod body 4 is provided with an annular concave first 10, the outer diameter of the annular concave first 10 is smaller than the outer diameter of the front end rod body 4, and the outer surface is provided with an external thread first 11 to form a front hole sealing male joint; the rear end of the axial through hole I9 is connected with a pressure sensor III and a flowmeter III; the pressure sensor III and the flowmeter III are respectively used for monitoring pressure signals and flow signals in the axial through hole I9 in real time; the outer diameter of the probe mounting rod 5 is smaller than that of the front rod body 4, and the rear end of the probe mounting rod is fixedly inserted into an axial through hole 9 at the left end of the front rod body 4; the center of the front end of the probe mounting rod 5 is provided with a camera mounting groove, the outer side of the camera mounting groove is provided with an axial channel I29, the axial channel I29 axially penetrates through the front end and the rear end of the probe mounting rod 5, the right end of the probe mounting rod is also communicated with the axial through hole I9, and the middle part of the probe mounting rod is provided with a cleaning electromagnetic valve 12 for opening or closing the axial channel I29; the front rubber hole sealing capsule 6 is sleeved in the annular limiting groove A30, the front end and the rear end of the front rubber hole sealing capsule 6 are fixedly connected with the front end and the rear end of the annular limiting groove A30 respectively, and a hole packer sealing space I is formed between the front rubber hole sealing capsule 6 and the front end rod body 4 and is communicated with the axial through hole I9 through a radial communication hole I; the first hole packer sealing space is connected with a pressure sensor A; a visual camera 7 is arranged in the camera mounting groove; the camera protection cover 8 is packaged at the opening end of the camera mounting groove;
The middle-section fracturing mechanism 2 mainly comprises a middle-section rod body 13 and a fracturing electromagnetic valve 19, wherein the axial center of the middle-section rod body 13 is provided with an axial through hole II 15 which is axially communicated, the center of the front end and the center of the rear end of the middle-section rod body are respectively provided with an annular accommodating cavity I16 and an annular accommodating cavity II 17, the middle section of the middle-section fracturing mechanism is radially provided with a plurality of fracturing channels 18, the inner end of each fracturing channel 18 is communicated with the axial through hole II 15, the outer end of each fracturing channel is communicated with the outside of the middle-section rod body 13, the middle part of the middle-section fracturing mechanism is connected with a pressure sensor IV and a flow meter IV, and the pressure sensor IV and the flow meter IV are respectively used for monitoring pressure signals and flow signals in the fracturing channels 18 in real time; the number of the fracturing electromagnetic valves 19 corresponds to the number of the fracturing channels 18, and the fracturing electromagnetic valves are assembled in the middle of the fracturing channels and used for controlling the on-off of the fracturing channels 18; the size of the annular containing cavity I16 is matched with the size of the annular concave platform I10, an internal thread structure I20 matched with the external thread structure I11 is arranged on the inner surface, and a female joint at the front end of the fracturing section is formed; an internal thread structure II 21 is arranged in the annular accommodating cavity II 17, and a female joint at the rear end of the fracturing section is formed; the front end of the middle section fracturing mechanism 2 is fixedly connected with the rear end of the front hole sealing mechanism 1 through the threaded fit of a female joint at the front end of the fracturing section and a male joint at the front hole sealing;
The rear hole packer mechanism 3 mainly comprises a rear end rod body 22 and a rear rubber hole sealing capsule 23; the axle center of the rear end rod body 22 is provided with an axial through hole III 24 which is axially communicated; an annular limiting groove B14 is formed in the outer portion of the middle section of the rear end rod body 22, a radial communication hole II which is communicated with the axial through hole III 24 and the outer space of the rear end rod body 22 is formed in the middle of the annular limiting groove B14, and a capsule electromagnetic valve II which is used for controlling the on-off of the radial communication hole II is arranged in the radial communication hole II; the front end of the rear end rod body 22 is provided with a second annular concave table 25, the outer diameter of the second annular concave table 25 is smaller than the outer diameter of the rear end rod body 22, the size of the second annular concave table is matched with the size of the second annular accommodating cavity 17, the outer surface of the second annular concave table is provided with a second external thread structure 27, and a rear hole sealing front end male connector is formed; the front end of the rear hole packer mechanism 3 is fixedly connected with the middle section fracturing mechanism 2 through the threaded fit of a front male connector of the rear hole packer and a rear female connector of the fracturing section; the rear rubber hole sealing capsule 23 is sleeved in the annular limiting groove B14, the front end and the rear end of the rear rubber hole sealing capsule 23 are fixedly connected with the front end and the rear end of the annular limiting groove B14 respectively, a hole packer sealing space II is formed between the rear rubber hole sealing capsule 23 and the rear end rod body 22, and the hole packer sealing space II is communicated with the axial through hole III 24 through a radial communication hole II; the second sealing space of the hole packer is connected with a pressure sensor B; the part of the axial through hole III 24 in front of the annular limiting groove B14 is connected with a pressure sensor II and a flowmeter II; the second pressure sensor and the second flowmeter are respectively used for monitoring pressure signals and flow signals at the front end of the third axial through hole 24; the part of the axial through hole III 24 behind the annular limiting groove B14 is connected with a pressure sensor I and a flowmeter I; the first pressure sensor and the first flowmeter are used for monitoring a pressure signal and a flow signal of the rear end of the third axial through hole 24 respectively.
In order to improve the cleaning effect on the lens and obtain clearer image data, the number of the first axial channels 29 is two, and each first axial channel 29 is provided with a cleaning electromagnetic valve 12 and is distributed on two opposite sides of the camera mounting groove.
In order to facilitate connection and disconnection of the high-pressure water injection steel pipe, the rear end of the rear end rod body 22 is provided with an annular concave third 26, the outer diameter of the annular concave third 26 is smaller than that of the rear end rod body 22, the outer surface of the annular concave third 26 is provided with an external thread structure third 28, and a rear end male connector for rear hole sealing is formed.
Preferably, the camera mounting groove is cylindrical.
Preferably, the outer diameters of the front rod 4, the middle rod 13 and the rear rod 22 are the same.
By arranging the visual camera at the front end of the front end rod body, a real-time image transmitted by the front end camera in the pushing process can be used for observing whether the designed cracking position surrounding rock is complete or not and whether the hole wall is smooth or not, and if so, whether the current cracking point meets the required standard or not can be reasonably judged; through the arrangement of the pressure sensor IV and the flow meter IV, the pressure signal and the flow signal in the fracturing channel can be monitored in real time, so that the cracking pressure of the hole sealing section can be quantified conveniently. The pressure sensor A and the pressure sensor B are respectively arranged in the first sealing space and the second sealing space of the hole packer, so that the pressure value of the sealing space of the hole packer can be conveniently collected in real time; the pressure sensor III and the flowmeter III are connected to the rear end of the axial through hole I, the pressure sensor II and the flowmeter II are arranged at the front end of the axial through hole III, and the pressure sensor I and the flowmeter I are arranged at the rear end of the axial through hole I, so that analysis of fault reasons can be conveniently carried out after faults occur, and the fault position can be rapidly determined.
The invention also provides a coal stratum hydraulic fracturing pressure effect evaluation and fault analysis method, which comprises a coal stratum hydraulic fracturing pressure monitoring device, and further comprises the following steps:
step one: the method comprises the steps that firstly, a front end female connector of a fracturing section and a rear end female connector of the fracturing section of a middle-section fracturing mechanism 2 are reliably connected with a front hole sealing male connector of a front hole sealing mechanism 1 and a rear hole sealing front end male connector of a rear hole sealing mechanism 3 through threads respectively, and a hole sealing device is formed; establishing communication connection between the cleaning electromagnetic valve 12, the fracturing electromagnetic valve 19, the capsule electromagnetic valve I, the capsule electromagnetic valve II, the visual camera 7, the pressure sensor A, the pressure sensor B, the pressure sensor IV, the flow meter IV, the pressure sensor III, the flow meter III, the pressure sensor II, the flow meter II, the pressure sensor I and the flow meter I and the control terminal, and checking whether each monitoring terminal operates normally; finally, connecting a rear male joint of the rear hole sealing of the rear hole packer mechanism 3 with a high-pressure water injection steel pipe, and conveying the hole packer into the fracturing hole by using a drilling machine;
step two: in the pushing process of the hole packer in the fracturing hole, image data are acquired in real time through the visual camera 7 so as to observe the structural characteristics of the surrounding rock of the fracturing hole in real time;
Step three: when the hole packer is pushed to the vicinity of the cracking point, the visual camera 7 at the front end is used for collecting image data in real time, observing whether the designed cracking position surrounding rock is complete or not and whether the hole wall is smooth or not, and if the cracking point position designed according to the drilling histogram does not accord with the cracking point standard, continuously searching for a proper cracking point;
step four: after the hole packer reaches the position of the cracking point, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be opened, a high-pressure water pump is started to inject high-pressure water into the first hole packer sealing space and the second hole packer sealing space by utilizing a high-pressure water injection steel pipe, pressure signals in the first hole packer sealing space and the second hole packer sealing space are monitored in real time through pressure sensors A and B, when the pressure in the first hole packer sealing space and the second hole packer sealing space reaches the designed hole sealing pressure, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be closed, the fracturing electromagnetic valve 19 is controlled to be opened, and the high-pressure water is supplied into the sealing space between the first hole packer sealing space and the second hole packer sealing space until the cracking point rock stratum is cracked by the high-pressure water;
step five: turning off the high-pressure water pump, continuing to advance to the next designed cracking point after the front rubber hole sealing capsule 6 and the rear rubber hole sealing capsule 23 are restored to the original state, and repeating the steps two to four;
Step six: during the process of pushing the hole packer and withdrawing the hole packer, acquiring and recording image data in real time through a visual camera 7, acquiring and recording pressure signals and flow signal data in real time through a pressure sensor IV, a flow meter IV, a pressure sensor A, a pressure sensor B, a pressure sensor III, a flow meter III, a pressure sensor II, a flow meter II, a pressure sensor I and a flow meter I, and evaluating fracturing effects according to the recorded data;
if a fault occurs, the analysis is performed by the following method:
s1: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, and after the high-pressure water is injected for a period of time, the cracking hole starts to discharge a large amount of water, so that the following four possibilities exist: i. the high-pressure water pressure is too high, so that the front rubber hole sealing capsule 6 is damaged and the fracturing fails; ii. The high-pressure water is excessively high, so that the rear rubber hole sealing capsule 23 is damaged and the fracturing fails; iii, the front rubber hole sealing capsule 6 and the rear rubber hole sealing capsule 23 are complete, the closed space is complete, only the peripheral rock mass of the fracture point rock stratum is fractured, the extension degree of the fracture to the deep part is low, and the penetration degree of the fracture of the peripheral rock mass of the closed space is large; iv, the hole packer is complete, gaps exist between the front rubber hole sealing capsule 6 and the rear rubber hole sealing capsule 23 and hole wall fracturing, and the sealing effect is poor;
For the ith condition, analyzing according to the recorded results of the first pressure sensor, the first flowmeter, the second pressure sensor and the second flowmeter, if the flow values of the first flowmeter and the second flowmeter are unequal, and the pressure values of the third pressure sensor and the second pressure sensor are lower than the set hole sealing pressure, determining that the front rubber hole sealing capsule 6 is damaged, so that the water outlet phenomenon of a fracturing hole is caused;
for the ii-th case, analyzing according to the recorded results of the first pressure sensor, the first flow meter, the second pressure sensor, the second flow meter, the third pressure sensor and the third flow meter, if the flow values of the first flow meter, the second flow meter and the third flow meter are equal, and the pressure values of the third pressure sensor, the second pressure sensor and the third pressure sensor are equal and lower than the set hole sealing pressure, then the damage of the rear rubber hole sealing capsule 23 can be determined, and the water outlet phenomenon of the fracturing hole is caused;
for the iii and iv cases, analyzing according to the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor, if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor and the flow value of the second pressure sensor are equal, observing the water trace around the hole wall by using the real-time image acquired by the visual camera 7, and if the water trace diffusion degree on the hole wall is larger, determining that a gap exists between the front rubber hole sealing capsule 6 or the rear rubber hole sealing capsule 23 and the hole wall, so as to cause the water outlet phenomenon of a fracturing hole; if no obvious water trace exists around the hole wall, more through cracks are formed near the cracking point, and the cracking degree is high, the phenomenon that the through cracks are formed around the cracking point to lead the cracking hole to discharge water can be determined;
S2: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, after the high-pressure water is injected for a period of time, the inside of the cracking hole does not produce water, and the peripheral holes also have no water, so that the following two possibilities are provided: i. the high-pressure water pump is damaged and cannot continuously boost pressure; ii. The fracture crack is more penetrating, and is penetrated again with the original penetrating crack around the fracture hole, and the high-pressure water flows to the deep part along the penetrating crack;
for the ith condition, analyzing according to the record structures of the first pressure sensor and the first flowmeter, if the flow value of the first flowmeter is unchanged for a long time, the pressure value of the first pressure sensor is always constant and the pressure is lower, and determining that the high-pressure water pump is damaged;
in the ii-th case, the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor are analyzed, and if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor is equal to the flow value of the second pressure sensor, the phenomenon that the fracture penetration degree is larger, the fracture penetration degree is penetrated with the original through fracture around the fracturing hole again, and high-pressure water flows to the deep part along the through fracture can be determined.
As a preferable mode, in the second step, if the front end of the lens of the visual camera 7 is found to be blurred and covered by dirt, the cleaning solenoid valve 12 is controlled to be opened so as to automatically clean the lens of the visual camera 7, and after the cleaning is completed, the cleaning solenoid valve 12 is controlled to be closed and the forward pushing is continued.
The method has simple steps, can collect front-end image data and pressure and flow data of key parts in real time, is favorable for reasonably evaluating the fracturing effect, can comprehensively analyze after faults occur, and is convenient for quickly determining the fault reasons.
Claims (7)
1. The hydraulic fracturing pressure monitoring device for the coal stratum comprises a front hole sealing mechanism (1), a middle section fracturing mechanism (2) and a rear hole packer mechanism (3); the method is characterized in that;
the front hole sealing mechanism (1) mainly comprises a front end rod body (4), a probe mounting rod (5), a front rubber hole sealing capsule (6), a visual camera (7) and a camera protection cover (8); the axle center of the front end rod body (4) is provided with an axial through hole I (9) which is axially communicated; an annular limiting groove A (30) is formed in the outer part of the middle section of the front end rod body (4), a radial communication hole I which is communicated with an axial through hole I (9) and the outer space of the front end rod body (4) is formed in the middle of the annular limiting groove A (30), and a capsule electromagnetic valve I which is used for controlling the on-off of the radial communication hole I is arranged in the radial communication hole I; the rear end of the front end rod body (4) is provided with an annular concave first (10), the outer diameter of the annular concave first (10) is smaller than the outer diameter of the front end rod body (4), and the outer surface of the annular concave first (10) is provided with an external thread structure first (11) to form a front hole sealing male joint; the rear end of the axial through hole I (9) is connected with a pressure sensor III and a flowmeter III; the pressure sensor III and the flowmeter III are respectively used for monitoring pressure signals and flow signals in the axial through hole I (9) in real time; the outer diameter of the probe mounting rod (5) is smaller than that of the front rod body (4), and the rear end of the probe mounting rod is fixedly inserted into an axial through hole I (9) at the left end of the front rod body (4); the center of the front end of the probe mounting rod (5) is provided with a camera mounting groove, the outer side of the camera mounting groove is provided with an axial channel I (29), the axial channel I (29) axially penetrates through the front end and the rear end of the probe mounting rod (5), the right end of the probe mounting rod is also communicated with the axial through hole I (9), and the middle part of the probe mounting rod is provided with a cleaning electromagnetic valve (12) for opening or closing the axial channel I (29); the front rubber hole sealing capsule (6) is sleeved in the annular limiting groove A (30), the front end and the rear end of the front rubber hole sealing capsule are fixedly connected with the front end and the rear end of the annular limiting groove A (30) respectively, and a hole packer sealing space I is formed between the front rubber hole sealing capsule (6) and the front end rod body (4) and is communicated with the axial through hole I (9) through a radial communication hole I; the first hole packer sealing space is connected with a pressure sensor A; a visual camera (7) is arranged in the camera mounting groove; the camera protection cover (8) is encapsulated at the opening end of the camera mounting groove;
The middle-section fracturing mechanism (2) mainly comprises a middle-section rod body (13) and a fracturing electromagnetic valve (19), wherein an axial through hole II (15) which is axially communicated is formed in the axis of the middle-section rod body (13), an annular accommodating cavity I (16) and an annular accommodating cavity II (17) are respectively formed in the center of the front end and the center of the rear end of the middle-section rod body, a plurality of fracturing channels (18) are radially formed in the middle section of the middle-section fracturing mechanism, the inner end of each fracturing channel (18) is communicated with the axial through hole II (15), the outer end of each fracturing channel is communicated with the outer part of the middle-section rod body (13), a pressure sensor IV and a flow meter IV are connected to the middle part of the middle-section fracturing mechanism, and the pressure sensor IV and the flow meter IV are respectively used for monitoring pressure signals and flow signals in the fracturing channels (18) in real time; the number of the fracturing electromagnetic valves (19) corresponds to the number of the fracturing channels (18), and the fracturing electromagnetic valves are assembled in the middle of the fracturing channels and used for controlling the on-off of the fracturing channels (18); the size of the annular accommodating cavity I (16) is matched with the size of the annular concave table I (10), an internal thread structure I (20) matched with the external thread structure I (11) is arranged on the inner surface, and a female joint at the front end of the fracturing section is formed; an internal thread structure II (21) is arranged in the annular accommodating cavity II (17) and forms a female joint at the rear end of the fracturing section; the front end of the middle section fracturing mechanism (2) is fixedly connected with the rear end of the front hole sealing mechanism (1) through the threaded fit of a female joint at the front end of the fracturing section and a male joint of the front hole sealing;
The rear hole packer mechanism (3) mainly comprises a rear end rod body (22) and a rear rubber hole sealing capsule (23); the axle center of the rear end rod body (22) is provided with an axial through hole III (24) which is axially communicated; an annular limiting groove B (14) is formed in the outer part of the middle section of the rear end rod body (22), a radial communication hole II which is communicated with an axial through hole III (24) and the outer space of the rear end rod body (22) is formed in the middle of the annular limiting groove B (14), and a capsule electromagnetic valve II which is used for controlling the on-off of the radial communication hole II is arranged in the radial communication hole II; the front end of the rear end rod body (22) is provided with a second annular concave table (25), the outer diameter of the second annular concave table (25) is smaller than the outer diameter of the rear end rod body (22), the size of the second annular concave table is matched with the size of the second annular accommodating cavity (17), the outer surface of the second annular concave table is provided with a second external thread structure (27), and a rear hole sealing front end male connector is formed; the front end of the rear hole packer mechanism (3) is fixedly connected with the middle section fracturing mechanism (2) through the threaded fit of a front male connector of the rear hole packer and a rear female connector of the fracturing section; the rear rubber hole sealing capsule (23) is sleeved in the annular limiting groove B (14), the front end and the rear end of the rear rubber hole sealing capsule are fixedly connected with the front end and the rear end of the annular limiting groove B (14) respectively, and a hole packer sealing space II is formed between the rear rubber hole sealing capsule (23) and the rear end rod body (22) and is communicated with the axial through hole III (24) through a radial communication hole II; the second sealing space of the hole packer is connected with a pressure sensor B; the part of the axial through hole III (24) in front of the annular limiting groove B (14) is connected with a pressure sensor II and a flowmeter II; the second pressure sensor and the second flowmeter are respectively used for monitoring pressure signals and flow signals at the front end of the third axial through hole (24); the part of the axial through hole III (24) behind the annular limiting groove B (14) is connected with a pressure sensor I and a flowmeter I; the first pressure sensor and the first flowmeter are used for monitoring a pressure signal and a flow signal of the rear end of the axial through hole III (24) respectively.
2. The device for monitoring the hydraulic fracturing pressure of the coal strata according to claim 1, wherein the number of the first axial passages (29) is two, and each first axial passage (29) is internally provided with a cleaning electromagnetic valve (12) and is oppositely distributed on two opposite sides of the camera mounting groove.
3. The device for monitoring the hydraulic fracturing pressure of the coal stratum according to claim 1 or 2, wherein an annular concave third (26) is arranged at the rear end of the rear end rod body (22), the outer diameter of the annular concave third (26) is smaller than that of the rear end rod body (22), an external thread structure third (28) is arranged on the outer surface of the annular concave third (26), and a rear end male joint of the rear hole sealing is formed.
4. A coal formation hydraulic fracturing pressure monitoring device according to claim 3, wherein the camera mounting groove is cylindrical.
5. The coal and rock stratum hydraulic fracturing pressure monitoring device according to claim 4, wherein the outer diameters of the front end rod body (4), the middle section rod body (13) and the rear end rod body (22) are the same.
6. A method for evaluating the hydraulic fracturing pressure effect and analyzing faults of a coal stratum, which comprises the hydraulic fracturing pressure monitoring device for the coal stratum according to any one of claims 1 to 4 and is characterized by further comprising the following steps:
Step one: firstly, a front end female connector of a fracturing section and a rear end female connector of the fracturing section of a middle-section fracturing mechanism (2) are reliably connected with a front hole sealing male connector of a front hole sealing mechanism (1) and a rear hole sealing front end male connector of a rear hole sealing mechanism (3) through threads, and a hole sealing device is formed; establishing communication connection between a cleaning electromagnetic valve (12), a fracturing electromagnetic valve (19), a capsule electromagnetic valve I, a capsule electromagnetic valve II, a visual camera (7), a pressure sensor A, a pressure sensor B, a pressure sensor IV, a flow meter IV, a pressure sensor III, a flow meter III, a pressure sensor II, a flow meter II, a pressure sensor I and a flow meter I and control terminals, and checking whether each monitoring terminal operates normally; finally, connecting a rear male joint of the rear hole sealing device mechanism (3) with the high-pressure water injection steel pipe, and conveying the hole sealing device into the fracturing hole by utilizing a drilling machine;
step two: in the pushing process of the hole packer in the fracturing hole, image data are acquired in real time through a visual camera (7) so as to observe the structural characteristics of the surrounding rock of the fracturing hole in real time;
step three: when the hole packer is pushed to the vicinity of the cracking point, the visual camera (7) at the front end is used for collecting image data in real time, observing whether the designed cracking position surrounding rock is complete or not and whether the hole wall is smooth or not, and if the cracking point position designed according to the drilling histogram does not accord with the cracking point standard, continuously searching for a proper cracking point;
Step four: after the hole packer reaches the position of the cracking point, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be opened, a high-pressure water pump is started to inject high-pressure water into the first hole packer sealing space and the second hole packer sealing space by utilizing a high-pressure water injection steel pipe, pressure signals in the first hole packer sealing space and the second hole packer sealing space are monitored in real time through pressure sensors A and B, when the pressure in the first hole packer sealing space and the second hole packer sealing space reaches the designed hole sealing pressure, the first capsule electromagnetic valve and the second capsule electromagnetic valve are controlled to be closed, a fracturing electromagnetic valve (19) is controlled to be opened, and the high-pressure water is supplied into the sealing space between the first hole packer sealing space and the second hole packer sealing space until the cracking point rock stratum is cracked by the high-pressure water;
step five: turning off the high-pressure water pump, continuing to push to the next designed cracking point after the front rubber hole sealing capsule (6) and the rear rubber hole sealing capsule (23) are restored to the original state, and repeating the second to fourth steps;
step six: during the process of pushing the hole packer and withdrawing the hole packer, image data are collected and recorded in real time through a visual camera (7), pressure signals and flow signal data are collected and recorded in real time through a pressure sensor IV, a flow meter IV, a pressure sensor A, a pressure sensor B, a pressure sensor III, a flow meter III, a pressure sensor II, a flow meter II, a pressure sensor I and a flow meter I, and the fracturing effect is evaluated according to the recorded data;
If a fault occurs, the analysis is performed by the following method:
s1: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, and after the high-pressure water is injected for a period of time, the cracking hole starts to discharge a large amount of water, so that the following four possibilities exist: i. the high-pressure water pressure is too high, so that the front rubber hole sealing capsule (6) is damaged and the fracturing fails; ii. The high-pressure water is excessively high, so that the rear rubber hole sealing capsule (23) is damaged and the fracturing fails; iii, the front rubber hole sealing capsule (6) and the rear rubber hole sealing capsule (23) are complete, the closed space is complete, only the peripheral rock mass of the fracturing point rock stratum is fractured, the extension degree of the fracture to the deep part is low, and the penetration degree of the fracture of the peripheral rock mass of the closed space is large; iv, the hole packer is complete, gaps exist between the front rubber hole sealing capsule (6) and the rear rubber hole sealing capsule (23) and hole wall fracturing, and the sealing effect is poor;
for the ith condition, analyzing according to the recorded results of the first pressure sensor, the first flowmeter, the second pressure sensor and the second flowmeter, if the flow values of the first flowmeter and the second flowmeter are unequal, and the pressure values of the third pressure sensor and the second pressure sensor are lower than the set hole sealing pressure, determining that the front rubber hole sealing capsule (6) is damaged, so that the water outlet phenomenon of a fracturing hole is caused;
In the ii-th case, analyzing according to the recorded results of the first pressure sensor, the first flow meter, the second pressure sensor, the second flow meter, the third pressure sensor and the third flow meter, if the flow values of the first flow meter, the second flow meter and the third flow meter are equal, and the pressure values of the third pressure sensor, the second pressure sensor and the third pressure sensor are equal and lower than the set hole sealing pressure, determining that the rear rubber hole sealing capsule (23) is broken, and causing the water outlet phenomenon of a fracturing hole;
for the iii and iv cases, analyzing according to the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor, if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor and the flow value of the second pressure sensor are equal, observing the water trace around the hole wall by using the real-time image acquired by the visual camera (7), and if the water trace diffusion degree on the hole wall is larger, determining that a gap exists between the front rubber hole sealing capsule (6) or the rear rubber hole sealing capsule (23) and the hole wall, so as to cause the water outlet phenomenon of a cracking hole; if no obvious water trace exists around the hole wall, more through cracks are formed near the cracking point, and the cracking degree is high, the phenomenon that the through cracks are formed around the cracking point to lead the cracking hole to discharge water can be determined;
S2: under the condition that the high-pressure water injection steel pipe is complete, after the hole packer is sealed, the cracking hole has no water leakage phenomenon, after the high-pressure water is injected for a period of time, the inside of the cracking hole does not produce water, and the peripheral holes also have no water, so that the following two possibilities are provided: i. the high-pressure water pump is damaged and cannot continuously boost pressure; ii. The fracture crack is more penetrating, and is penetrated again with the original penetrating crack around the fracture hole, and the high-pressure water flows to the deep part along the penetrating crack;
for the ith condition, analyzing according to the recorded results of the first pressure sensor and the first flowmeter, if the flow value of the first flowmeter is unchanged for a long time, the pressure value of the first pressure sensor is always constant and the pressure is lower, and determining that the high-pressure water pump is damaged;
in the ii-th case, analysis is performed according to the recorded results of the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the fourth pressure sensor, and if the pressure values of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor are equal and are larger than the set hole sealing pressure, and meanwhile, the flow value of the fourth pressure sensor is equal to the flow value of the second pressure sensor, the phenomenon that the fracture penetration degree is larger, the fracture penetration degree is penetrated again with the original penetration fracture around the fracturing hole, and high-pressure water flows to the deep part along the penetration fracture can be determined.
7. The method for evaluating the hydraulic fracturing pressure effect and analyzing faults of a coal stratum according to claim 6, wherein in the second step, if the front end of a lens of a visual camera (7) is found to be fuzzy and covered by dirt, a cleaning electromagnetic valve (12) is controlled to be opened so as to automatically clean the lens of the visual camera (7), and after the cleaning is finished, the cleaning electromagnetic valve (12) is controlled to be closed and the forward pushing is continued.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111550919.4A CN114396249B (en) | 2021-12-17 | 2021-12-17 | Coal stratum hydraulic fracturing pressure monitoring device, effect evaluation and fault analysis method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111550919.4A CN114396249B (en) | 2021-12-17 | 2021-12-17 | Coal stratum hydraulic fracturing pressure monitoring device, effect evaluation and fault analysis method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114396249A CN114396249A (en) | 2022-04-26 |
| CN114396249B true CN114396249B (en) | 2023-12-08 |
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| CN105758561A (en) * | 2016-04-05 | 2016-07-13 | 中国矿业大学 | Visual uniformly-distributed hydraulic fracturing ground stress measurement device and measurement method |
| CN110439497A (en) * | 2019-07-31 | 2019-11-12 | 中国矿业大学 | Drill multistage closure, fracturing, slip casting, water filling integration apparatus and application method |
| CN111236917A (en) * | 2020-01-14 | 2020-06-05 | 西安科技大学 | Complete equipment and method for coal rock water-acid high-pressure presplitting softening scour prevention and permeability increase |
| CN113073977A (en) * | 2021-03-29 | 2021-07-06 | 中国矿业大学 | Integrated hydraulic fracturing device and method for underground coal rock stratum |
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| CN108561083B (en) * | 2018-03-09 | 2021-05-18 | 中国矿业大学 | Long-distance drilling and fracturing integrated equipment and method under mine |
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| CN105758561A (en) * | 2016-04-05 | 2016-07-13 | 中国矿业大学 | Visual uniformly-distributed hydraulic fracturing ground stress measurement device and measurement method |
| CN110439497A (en) * | 2019-07-31 | 2019-11-12 | 中国矿业大学 | Drill multistage closure, fracturing, slip casting, water filling integration apparatus and application method |
| CN111236917A (en) * | 2020-01-14 | 2020-06-05 | 西安科技大学 | Complete equipment and method for coal rock water-acid high-pressure presplitting softening scour prevention and permeability increase |
| CN113073977A (en) * | 2021-03-29 | 2021-07-06 | 中国矿业大学 | Integrated hydraulic fracturing device and method for underground coal rock stratum |
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