CN116380679A - Dry-hot rock fracturing experiment machine capable of tracking crack propagation path and experiment method - Google Patents

Dry-hot rock fracturing experiment machine capable of tracking crack propagation path and experiment method Download PDF

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Publication number
CN116380679A
CN116380679A CN202310234325.5A CN202310234325A CN116380679A CN 116380679 A CN116380679 A CN 116380679A CN 202310234325 A CN202310234325 A CN 202310234325A CN 116380679 A CN116380679 A CN 116380679A
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fracturing
pumping
pressure
rock sample
standard rock
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解经宇
乔伟
陈秋
刘一凡
金雪
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China University of Mining and Technology CUMT
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China University of Mining and Technology CUMT
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP 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
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/06—Special adaptations of indicating or recording means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
    • G01N3/12—Pressure testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0001—Type of application of the stress
    • G01N2203/0003—Steady
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0016—Tensile or compressive
    • G01N2203/0019—Compressive
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/003—Generation of the force
    • G01N2203/0042—Pneumatic or hydraulic means
    • G01N2203/0048—Hydraulic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G01N2203/0062—Crack or flaws
    • G01N2203/0066—Propagation of crack
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/0658—Indicating or recording means; Sensing means using acoustic or ultrasonic detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/0664—Indicating or recording means; Sensing means using witness specimens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/067—Parameter measured for estimating the property
    • G01N2203/0676—Force, weight, load, energy, speed or acceleration
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/10—Geothermal energy

Abstract

The invention discloses a dry-hot rock fracturing experiment machine capable of tracking a crack propagation path and an experiment method. The fracturing fluid pumping device comprises three groups of pumping systems. The hydraulic fracture tracking device comprises a liquid storage tank and a mold filling silicon injection pump, and mold filling silicon gel is filled in the container. The method can simulate the fracturing process of the standard dry-hot rock core under different geological and engineering parameter conditions, and can realize the tracking of hydraulic fracture through the pumped filling silica gel.

Description

Dry-hot rock fracturing experiment machine capable of tracking crack propagation path and experiment method
Technical Field
The invention relates to the technical field of hydraulic fracturing of hot dry rock, in particular to a hot dry rock fracturing experiment machine capable of tracking a crack propagation path and an experiment method.
Background
The dry-hot rock type geothermal energy is taken as an emerging environment-friendly large-reserve energy source, and is expected to become a new direction of energy structure transformation. Hydraulic fracturing is a core means for constructing artificial thermal storage, namely, a large amount of liquids with different properties are injected into a thermal reservoir to fracture rock, and then a working medium circulation loop which is communicated with each other is established through hydraulic cracks to extract heat energy for power generation. Since the 70 s of the last century, attempts have been made to develop dry rock resources in several countries. However, the system is limited by key technologies such as artificial thermal storage construction, seismic prevention and control induction and the like, and the number of the successfully operated enhanced geothermal systems is increased internationally. Therefore, the development of the research on the hydraulic fracturing mechanism of the dry-hot rock is of great importance.
The indoor hydraulic fracturing physical simulation test system can simulate the hydraulic fracturing process under different geological and engineering parameter conditions. However, at present, the monitoring means for the internal hydraulic fracture morphology of the fractured sample is single, the common acoustic emission means cannot directly acquire the fracture morphology and the error is often larger, and the CT scanning technology has higher requirements on resolution, so that the tiny fracture is often difficult to capture under the low resolution condition.
Disclosure of Invention
The invention aims to provide a dry hot rock fracturing experiment machine and an experiment method capable of tracking a crack propagation path, which can simulate the hydraulic fracturing process of the dry hot rock under different geological and engineering parameter conditions and can effectively track the hydraulic crack propagation path of the rock.
In order to achieve the above purpose, the invention discloses a dry hot rock fracturing experiment machine capable of tracking a crack propagation path, which comprises a modular ground stress device, a fracturing fluid pumping device, a hydraulic crack tracking device, an acoustic emission device and a control device; wherein, the liquid crystal display device comprises a liquid crystal display device,
the simulated ground stress device comprises a device main body, a circular pressing block, a confining pressure container and a fixed table top, wherein the device main body is a closed container, the fixed table top is positioned at the bottom of a closed space of the device main body, the confining pressure container is arranged on the fixed table top, the circular pressing block is positioned above the confining pressure container, a standard rock sample is placed in the confining pressure container, and the fixed table top is positioned between the fixed table top and the circular pressing block; wherein the circular briquette is used for applying downward axial pressure to the standard rock sample, and the confining pressure vessel is used for applying radial pressure to the standard rock sample;
the fracturing fluid pumping device comprises three groups of pumping systems: the system comprises a slick water and clear water pumping system, a hydrochloric acid and hydrofluoric acid pumping system and a supercritical carbon dioxide pumping system, which are respectively used for injecting different liquids for standard rock samples of different rock types; each group of pumping system comprises a fracturing fluid storage box body and a high-pressure injection pump for injecting fracturing fluid into the standard rock sample;
the hydraulic fracture tracking device comprises a liquid storage tank and a mold filling silica gel injection pump, wherein the mold filling silica gel is filled in the liquid storage tank, and the mold filling silica gel injection pump is used for pumping the mold filling silica gel into a sample after a hydraulic fracture experiment is completed, so that the mold filling silica gel is moved in a hydraulic fracture to intuitively acquire the form and the expansion path of the hydraulic fracture;
the fracturing fluid pumping device and the hydraulic fracture tracking device are connected with the simulated ground stress device through a liquid pipeline;
the acoustic emission device comprises a full-information acoustic emission analyzer host and a plurality of acoustic emission probes, and the acoustic emission probes are arranged in the round pressing block and around the standard rock sample;
the control device comprises an integrated control cabinet and a computer and is used for controlling the block ground stress device, the fracturing fluid pumping device, the hydraulic fracture tracking device and the acoustic emission device.
Further, the confining pressure container is composed of two semi-cylindrical steel bodies which all contain grooves, and the grooves form a closed space.
Further, the standard rock sample is provided with a simulated shaft along the axis of the standard rock sample, a through hole is formed in the center of the round pressing block, and a pumping pipeline on the pressure pumping device is connected with the simulated shaft through the through hole.
Further, the simulated ground stress device further comprises a waste liquid recovery device, wherein the waste liquid recovery device is positioned at the bottom of the device main body, and a liquid pipeline leading to the recovery device is arranged on the fixed table top.
On the other hand, the invention also discloses a dry-hot rock fracturing experimental method capable of tracking the crack propagation path, which comprises the following experimental steps:
step S1, drilling a hole in the center of one end face of a standard rock sample, and presetting a simulation shaft capable of conducting fracturing fluid, wherein the outer wall of the simulation shaft and the inner wall of the hole are sealed by epoxy resin bar planting glue;
s2, heating the standard rock sample processed in the step to a specified temperature in a heating furnace, wrapping a high-strength temperature-resistant rubber film outside the standard rock sample, and presetting strain gauges between the rubber film and the standard rock sample, wherein the number of the strain gauges is not less than 6, namely 4 in the radial direction, and one upper end face and one lower end face are respectively preset;
s3, placing the prepared standard rock sample on a fixed table top, connecting a pumping pipeline with the simulation shaft in a threaded manner, slowly applying shaft pressure and confining pressure, and performing shaft pressure and confining pressure experiments on the standard rock sample; in order to ensure that the standard rock sample is not destroyed before the fracturing experiment, the axial pressure and the confining pressure are firstly applied to smaller values of the axial pressure and the confining pressure, and then the other pressure value is slowly adjusted to a set value;
s4, starting a fracturing fluid pumping device, and selecting fracturing fluid to be pumped according to different rock types of a standard rock sample; before pumping fracturing fluid, the acoustic emission device is started first, then pumping is started, and the original acoustic emission waveform record and the pressure-time curve are recorded in real time in the fracturing process.
S5, after the pressure curve is subjected to fluctuation and stabilized at a certain value, and fracturing fluid overflows the surface of the sample, the fracturing experiment is finished, the acoustic emission device is turned off, the waste liquid is treated, and the standard rock sample is waited for cooling;
and S6, starting the hydraulic fracture tracking device, injecting the mold filling silica gel into the fractured standard rock sample, recording the mold filling silica gel pump injection pressure in real time, standing for more than 6 hours, taking out the standard rock sample, and cleaning the test system.
And S7, taking out the standard rock sample, placing the standard rock sample in a closed acid container, and taking out the solidified and insoluble filling silica gel after the standard rock sample is dissolved, so that a hydraulic fracture propagation path can be obtained.
Further, the test sample is radially wrapped with a high-strength temperature-resistant rubber film before the test, so as to seal the hydraulic oil in the confining pressure applying process.
Further, after the pumping pressure curve is stabilized around a certain pressure value after being subjected to fluctuation and the boundary of the standard rock sample has fracturing fluid overflows, the end of the fracturing test can be determined.
Further, in order to prevent a new hydraulic fracture from being formed in the fracture tracking process, the pumping pressure of the mold filling silica gel does not exceed the stable pumping pressure after fluctuation.
The beneficial effects of the invention are as follows:
(1) According to the invention, on the basis of a dry-hot rock hydraulic fracturing physical simulation test, the expansion path of the hydraulic fracture can be tracked in a mode of sampling pump injection molding silica gel, so that the problem that the crack morphology is difficult to intuitively obtain in an indoor fracturing physical simulation test is solved;
(2) According to the invention, different fracturing fluids can be injected for different types of rock samples, so that the expansibility of a fracturing test is better, and the test mode is more flexible;
(3) The experimental machine is manufactured in a modularized mode, is controlled in an integrated mode, and can effectively improve the test efficiency;
(4) According to the invention, the template filling silica gel is used as the reconstruction of the crack path after the standard rock sample is fractured, so that the crack can be displayed in a panoramic manner, and the intuitiveness is better.
Drawings
FIG. 1 is a schematic structural diagram of a hydraulic fracturing physical experiment machine for a dry hot rock core;
FIG. 2 is a schematic diagram of a simulated ground stress apparatus;
FIG. 3 is a schematic diagram of the distribution positions of the acoustic emission probe and standard rock sample according to the present invention.
In the figure, 1-computer; 2-an integrated control cabinet; 3-a fracturing fluid pumping device; 3-1-a slimy water and clear water pumping system; 3-2-hydrochloric acid and hydrofluoric acid pumping system; 3-3-supercritical carbon dioxide pumping system; 3-32-carbon dioxide generating device; 4-a hydraulic fracture tracking device; 4-1-filling a mold silica gel injection pump; 4-3-liquid storage tank; 3-11-valve I; 3-21-valve II; 3-31-valve III; 4-2-valve IV; 5-simulating a ground stress device; 5-0 parts of a device main body and 5-1 parts of a round pressing block; 5-2-confining pressure container; 5-3-standard rock sample; 5-31 acoustic emission probes; 5-4-fixing the table top; 5-5-waste liquid recovery device; 5-6-frac fluid flow channels; 5-7-simulating a wellbore; 6-pumping line.
Detailed Description
The invention will be described in further detail with reference to the accompanying drawings and specific examples.
As shown in fig. 1, a dry-hot rock fracturing experiment machine capable of tracking a crack propagation path comprises a simulated ground stress device 5, a fracturing fluid pumping device 3, a hydraulic crack tracking device 4, an acoustic emission device and a control device 2. The fracturing fluid pumping device 3 and the hydraulic fracture tracking device 4 are connected with the simulated ground stress device 5 through a pumping pipeline 6.
As shown in fig. 2, the simulated ground stress apparatus 5 comprises a confining pressure loading unit and a shaft pressure loading unit, wherein the confining pressure loading unit and the loading unit are arranged in one apparatus main body 5-0, the shaft pressure loading unit comprises a circular pressing block 5-1 and a hydraulic device for driving the circular pressing block to press a standard rock sample 5-3, the diameter of the circular pressing block 5-1 is consistent with that of the standard rock sample 5-3, and the size of the standard rock sample is as follows: phi 50 mm by 100 mm, one end face of a standard rock sample 5-3 is placed on a fixed table top 5-4 in the experimental process, and the other end face is directly contacted with a round pressing block 5-1 to bear pressure; the confining pressure loading system is a confining pressure container 5-2, the confining pressure container 5-2 is two semicircular column steel bodies with grooves, and after the steel bodies are in butt joint, fixed and sealed, the test sample can be circumferentially surrounded to expose the end face. The two grooves are combined into a closed space, the grooves are communicated with the hydraulic device, and hydraulic oil enters the grooves in the confining pressure applying process to be in direct contact with the high-strength temperature-resistant rubber film wrapped outside the sample so as to apply confining pressure. The hydraulic device conducts pressure to the standard rock sample 5-3 by applying pressure to the hydraulic oil. The confining pressure loading unit is used for uniformly loading the confining pressure of the cylindrical standard rock sample 5-3 through hydraulic oil in the closed loop, and the hydraulic device is used for controlling the oil pressure in the loop so as to adjust the confining pressure. Rated confining pressure is set to 100MPa, and rated shaft pressure is set to 100t. The bottom of the simulated ground stress device is provided with a waste liquid recovery device 5-5, when the fracturing experiment is carried out to a certain stage, part of fracturing liquid can overflow the surface of the sample and flows into the waste liquid recovery device 5-5 through fracturing liquid flowing channels 5-6 distributed on the fixed table top under the action of gravity.
Before the experiment, the sample is heated to a specified temperature outside the experiment system, and then is put into the experiment system to start the experiment. The semi-cylindrical steel body, the cylindrical pressing block and the fixed table top which are subjected to confining pressure are sequentially provided with a heat insulation device nanometer heat insulation plate and an acoustic emission probe 5-31 from inside to outside; the acoustic emission probe 5-31 can be detached from the semi-cylindrical steel body, the round pressing block 5-1 and the fixed table top.
The fracturing fluid pump injection device mainly comprises three groups of independent liquid pump injection systems, wherein the three groups of independent liquid pump injection systems are respectively a slickwater and clean water pump injection system 3-1, a hydrochloric acid and hydrofluoric acid pump injection system 3-2 and a supercritical carbon dioxide pump injection system 3-3, each group of pump injection systems comprises a fracturing fluid storage box body and a high-pressure injection pump for injecting fracturing fluid into a sample, and the supercritical carbon dioxide pump injection system further comprises a supercritical carbon dioxide generating device 3-32. Each pumping system is provided with independent valve controls such as valves I3-11, valves II3-21 and valves III3-31, three parallel pumping routes can be connected with a preset injection pipe in a sample, and two or more fracturing fluids can not be pumped simultaneously in an experiment. The viscosity distribution range of the viscosity-variable slick water pumped is not more than 100 mPa.s; the fracturing fluid storage tanks and pumping lines in the hydrochloric acid and hydrofluoric acid pumping system 3-2 should be made of lead. When the temperature is higher than 31.1 ℃ and the pressure is higher than 7.38MPa, the carbon dioxide enters a supercritical state. Rated injection displacement 150mL/min.
The hydraulic fracture tracking device 4 comprises a mold filling silica gel injection pump 4-1 and a liquid storage tank 4-3 for storing the mold filling silica gel, wherein the mold filling silica gel injection pump 4-1 is used for pumping the mold filling silica gel into a sample after the hydraulic fracture experiment is completed, so that the mold filling silica gel is moved in the hydraulic fracture, and the form and the expansion path of the hydraulic fracture can be intuitively obtained by carrying out acid dissolution on the sample after the mold filling silica gel is solidified. The poured silica gel is led through a valve IV4-2 to a standard rock sample 5-3 in a simulated earth stress device 5.
The hydraulic fracture tracking device 4 is started after the fracturing experiment is completed, and the mold filling silica gel is a chemical substance which has relatively good fluidity, can enter into small hydraulic fractures and is insoluble in acid, and the solidification time of the mold filling silica gel in the sample is generally not less than 6 hours. The acid solution for dissolving the sample should be earth acid (mixture of hydrochloric acid and hydrofluoric acid) with the concentration of 12-20 for the carbonate type dry-hot rock sample. The center of the round pressing block 5-1 is provided with a round hole which can accommodate the passage of a pumping pipeline connected with the sample, and the pumping pipeline is connected with a simulation shaft 5-7 preset in the sample through threads.
As shown in FIG. 3, the acoustic emission device comprises 16 detachable acoustic emission probes which are arranged in the circular pressing blocks of the confining pressure loading system and the shaft pressure loading system, and a full-information acoustic emission analyzer host electrically connected with the acoustic emission probes. The acoustic emission probes are uniformly distributed around the sample, specifically, 4 probes are distributed on the upper and lower end faces respectively, the phase angles of the 4 probes distributed on the outer side of each end face are 90 degrees, 4 radial probes are distributed on the upper half part and the lower half part of the sample respectively, and the phase angles are still 90 degrees, and the probes are distributed in an up-down staggered mode.
As shown in fig. 1, the control device comprises an integrated control cabinet 2 for controlling the simulated ground stress device 5, the fracturing fluid pumping device 3 and the hydraulic fracture tracking device 4, and a computer 1 for controlling the devices and the sound emission device.
The dry-hot rock core hydraulic fracturing physical experiment machine can track the expansion path of hydraulic cracks in a mode of sampling pump injection of the filling silica gel on the basis of the dry-hot rock hydraulic fracturing physical simulation test, and solves the problem that the indoor fracturing physical simulation test is difficult to intuitively acquire the crack form. And a large number of experiments can guide actual production, avoid blind operation of the actual production and improve production efficiency. In addition, the dry-hot rock core hydraulic fracturing physical simulation system has the advantages of being in a device operation and in an integrated control.
The invention also discloses a dry-hot rock fracturing experimental method capable of tracking the crack propagation path, which comprises the following steps:
step one, processing a rock sample to a standard core size, namely phi 50 mm or 100 mm, drilling a hole in the center of one end face, wherein the drilling diameter is 5-7 mm, and the drilling depth is generally 40-75 mm according to experimental setting and is used for presetting a simulated shaft capable of conducting fracturing fluid. The simulated shaft is a thin steel pipe with the inner diameter of 3-4 mm and the wall thickness of 1 mm. The outer wall of the simulated shaft and the inner wall of the drilled hole are sealed by epoxy resin bar planting glue.
And step two, heating the standard rock sample 5-3 processed in the step one to a specified temperature in a heating furnace outside the experimental machine, wherein the temperature is generally not more than 300 ℃, and the temperature should be slowly raised in the heating process so as to prevent the thermal cracking phenomenon of the sample before the experiment. And then wrapping a high-strength temperature-resistant rubber film outside the sample, presetting strain gauges between the rubber film and the sample, wherein the number of the strain gauges is not less than 6, namely 4 in the radial direction, and one upper end face and one lower end face are respectively preset.
And thirdly, placing the prepared sample on a fixed table of a test system, connecting an injection pipeline with a simulated shaft in a threaded manner, then slowly applying axial pressure and confining pressure, and in order to ensure that the rock sample is not damaged before a fracturing experiment, firstly applying the axial pressure and confining pressure to smaller values of the axial pressure and confining pressure, and then slowly adjusting the other pressure value to a set value. At this time, the test system sequentially comprises a sample, a strain gauge, a rubber membrane, a confining pressure and axial pressure applying device, a nano heat insulating plate, an acoustic emission probe and the like from inside to outside.
Step four, preparing fracturing fluid to be pumped, namely enabling clear water and slick water to be suitable for all rock samples, enabling hydrochloric acid to be generally used for carbonate rock samples, enabling hydrofluoric acid to be generally used for granite samples, enabling supercritical carbon dioxide to be generally used for a fracturing process with special requirements, starting an acoustic emission detection system before pumping the fracturing fluid, and then starting pumping, and recording acoustic emission original waveform records and pressure-time curves in real time in the fracturing process.
And fifthly, after the pressure curve is subjected to fluctuation and stabilized at a certain value, and fracturing fluid overflows the surface of the sample, the fracturing experiment is finished, the acoustic emission system is closed, the waste liquid is treated, and the sample is waited for cooling.
Step six, preparing the filling silica gel and starting pumping, recording the pumping pressure of the filling silica gel in real time, wherein the pumping pressure is not larger than the stable pressure in the step four, stopping pumping the filling silica gel after the pressure drops by 20% once the filling silica gel meets overpressure, preventing the filling silica gel from fracturing the sample, stopping filling after the filling silica gel overflows the surface of the sample, taking out the sample after standing for more than 6 hours, and cleaning the test system.
Step seven, placing the sample in a closed acid container, wherein the carbonate rock sample is generally immersed in hydrochloric acid, and the dissolution of the sample can be completed within 12 hours; the granite sample is generally placed in hydrofluoric acid, and is usually required to be soaked for more than 72 hours to be dissolved, and after the sample is dissolved, the solidified and insoluble filling silica gel is taken out, namely the reconstruction and tracking of the hydraulic fracture propagation path.
The main factors affecting hydraulic fracturing and crack propagation of rock are: the characteristics of the rock mass of the fracturing stratum mainly comprise rock mass mechanical properties, crack development conditions and the like of the rock, and are related to samples used in experiments; fracturing formation stress, including true formation ground stress distribution, ground stress difference coefficient and the like, is related to the applied axial pressure and confining pressure; the type, the property and the pumping mode of the fracturing fluid are related to the type of the pumping fracturing fluid; wellbore simulation conditions, etc. Therefore, in the process of physical simulation test design, the influence of the factors is considered, hydraulic fracturing physical simulation experiments are carried out on different samples, hydraulic fracturing physical simulation cutting in is carried out from an indoor horizontal well, a crack extension mechanism in the hydraulic fracturing process is discussed, the fracturing effect is evaluated and the fracturing process is guided to be optimized by injecting mold filling silica gel into the samples after the experiments, and finally, the hydraulic fracturing process is popularized to field actual production conditions, so that basis is provided for optimizing field hydraulic fracturing parameters.
The dry hot rock core hydraulic fracturing physical simulation experiment machine capable of tracking the hydraulic fracture propagation path is used for exploring the formation condition and mechanism of the net-shaped fracture in the hydraulic fracturing process of the dry hot rock, and the similarity between the field prototype and the experimental model is required to be considered in the experimental process.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention, and the present invention is defined in the claims.

Claims (8)

1. The dry-hot rock fracturing experiment machine capable of tracking the crack propagation path is characterized by comprising a modular ground stress device, a fracturing liquid pumping device, a hydraulic crack tracking device, an acoustic emission device and a control device; wherein, the liquid crystal display device comprises a liquid crystal display device,
the simulated ground stress device comprises a device main body, a circular pressing block, a confining pressure container and a fixed table top, wherein the device main body is a closed container, the fixed table top is positioned at the bottom of a closed space of the device main body, the confining pressure container is arranged on the fixed table top, the circular pressing block is positioned above the confining pressure container, a standard rock sample is placed in the confining pressure container, and the fixed table top is positioned between the fixed table top and the circular pressing block; wherein the circular briquette is used for applying downward axial pressure to the standard rock sample, and the confining pressure vessel is used for applying radial pressure to the standard rock sample;
the fracturing fluid pumping device comprises three groups of pumping systems: the system comprises a slick water and clear water pumping system, a hydrochloric acid and hydrofluoric acid pumping system and a supercritical carbon dioxide pumping system, which are respectively used for injecting different liquids for standard rock samples of different rock types; each group of pumping system comprises a fracturing fluid storage box body and a high-pressure injection pump for injecting fracturing fluid into the standard rock sample;
the hydraulic fracture tracking device comprises a liquid storage tank and a mold filling silica gel injection pump, wherein the mold filling silica gel is filled in the liquid storage tank, and the mold filling silica gel injection pump is used for pumping the mold filling silica gel into a sample after a hydraulic fracture experiment is completed, so that the mold filling silica gel is moved in a hydraulic fracture to intuitively acquire the form and the expansion path of the hydraulic fracture;
the fracturing fluid pumping device and the hydraulic fracture tracking device are connected with the simulated ground stress device through a liquid pipeline;
the acoustic emission device comprises a full-information acoustic emission analyzer host and a plurality of acoustic emission probes, and the acoustic emission probes are arranged in the round pressing block and around the standard rock sample;
the control device comprises an integrated control cabinet and a computer and is used for controlling the block ground stress device, the fracturing fluid pumping device, the hydraulic fracture tracking device and the acoustic emission device.
2. The dry hot rock fracturing tester capable of tracking a crack propagation path according to claim 1, wherein the confining pressure container is composed of two semicircular column steel bodies each containing a groove, and the grooves form a closed space.
3. The dry-hot rock fracturing experiment machine capable of tracking a crack propagation path according to claim 1, wherein the standard rock sample is provided with a simulated shaft along the axis of the standard rock sample, a through hole is formed in the center of the round pressing block, and a pumping pipeline on the pressure pumping device is connected with the simulated shaft through the through hole.
4. The dry hot rock fracturing experiment machine capable of tracking a crack propagation path according to claim 1, wherein the simulated ground stress device further comprises a waste liquid recovery device, the waste liquid recovery device is positioned at the bottom of the device main body, and a liquid pipeline leading to the recovery device is arranged on the fixed table top.
5. A method of testing a dry hot rock fracture according to claim 1, based on the machine of any one of claims 1-4, comprising the following steps:
step S1, drilling a hole in the center of one end face of a standard rock sample, and presetting a simulation shaft capable of conducting fracturing fluid, wherein the outer wall of the simulation shaft and the inner wall of the hole are sealed by epoxy resin bar planting glue;
s2, heating the standard rock sample subjected to the processing to a specified temperature in a heating furnace, wrapping a high-strength temperature-resistant rubber film outside the standard rock sample, and presetting strain gauges between the high-strength temperature-resistant rubber film and the standard rock sample, wherein at least 6 strain gauges are preset, namely 4 strain gauges are radially preset, and the upper end face and the lower end face of each strain gauge are respectively arranged;
s3, placing the prepared standard rock sample on a fixed table top, connecting a pumping pipeline with the simulation shaft in a threaded manner, slowly applying shaft pressure and confining pressure, and performing shaft pressure and confining pressure experiments on the standard rock sample; in order to ensure that the standard rock sample is not destroyed before the fracturing experiment, the axial pressure and the confining pressure are firstly applied to smaller values of the axial pressure and the confining pressure, and then the other pressure value is slowly adjusted to a set value;
s4, starting a fracturing fluid pumping device, and selecting fracturing fluid to be pumped according to different rock types of a standard rock sample; before pumping fracturing fluid, the acoustic emission device is started first, then pumping is started, and the original acoustic emission waveform record and the pressure-time curve are recorded in real time in the fracturing process.
S5, after the pressure curve is subjected to fluctuation and stabilized at a certain value, and fracturing fluid overflows the surface of the sample, the fracturing experiment is finished, the acoustic emission device is turned off, the waste liquid is treated, and the standard rock sample is waited for cooling;
and S6, starting the hydraulic fracture tracking device, injecting the mold filling silica gel into the fractured standard rock sample, recording the mold filling silica gel pump injection pressure in real time, standing for more than 6 hours, taking out the standard rock sample, and cleaning the test system.
And S7, taking out the standard rock sample, placing the standard rock sample in a closed acid container, and taking out the solidified and insoluble filling silica gel after the standard rock sample is dissolved, so that a hydraulic fracture propagation path can be obtained.
6. The dry-hot rock fracturing test method capable of tracking the propagation path of a fracture according to claim 5, wherein the test sample is radially wrapped with a high-strength temperature-resistant rubber membrane for sealing hydraulic oil in the confining pressure application process before the test.
7. The method for testing dry-thermal rock fracturing capable of tracking a crack propagation path according to claim 5, wherein the completion of the fracturing test is determined when the pumping pressure curve is stabilized around a certain pressure value after being subjected to fluctuation and the boundary of the standard rock sample has fracturing fluid overflows.
8. The method of claim 6, wherein the pumping pressure of the mold-filled silica gel does not exceed the steady pumping pressure after the fluctuation in order to prevent new hydraulic cracks from forming during the crack tracing.
CN202310234325.5A 2023-03-13 2023-03-13 Dry-hot rock fracturing experiment machine capable of tracking crack propagation path and experiment method Pending CN116380679A (en)

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Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090119082A1 (en) * 2007-11-01 2009-05-07 Schlumberger Technology Corporation Reservoir fracture simulation
CN101968348A (en) * 2010-09-07 2011-02-09 中国石油大学(北京) Method for visually monitoring fracture crack
CN103266888A (en) * 2013-05-21 2013-08-28 中国石油大学(华东) System and method for visualization fracturing simulation experiment
CN103883301A (en) * 2014-03-31 2014-06-25 中国矿业大学 Physical simulation method of coal-bed gas well hydraulic fractures
CN105675724A (en) * 2016-01-29 2016-06-15 中国矿业大学 Acoustic emission positioning monitoring device and method for hydraulic fracturing fissure field of coal body containing gas
CN106442147A (en) * 2016-08-08 2017-02-22 温州大学 Steam or hydraulic fracturing consolidation test device
CN107893652A (en) * 2017-09-30 2018-04-10 中国石油大学(华东) The hydraulic fracturing analogue experiment installation and method of the enhanced geothermal system of hot dry rock
CN108535112A (en) * 2017-03-03 2018-09-14 中国石油化工股份有限公司 A kind of experiment analytical method for shale samples compressibility research
CN108732010A (en) * 2017-04-24 2018-11-02 中国石油天然气股份有限公司 A kind of simulation of fracturing fracture and evaluating apparatus and method
CN110924933A (en) * 2019-11-18 2020-03-27 中国石油集团川庆钻探工程有限公司 Visual experiment method for dynamically simulating shale fracturing fracture network
CN110987639A (en) * 2019-12-16 2020-04-10 重庆大学 Method for determining true triaxial hydraulic fracturing fracture expansion volume and fracture morphology by freezing method
CN113514337A (en) * 2020-04-09 2021-10-19 新奥科技发展有限公司 Hot dry rock rupture pressure test device and method
CN114441336A (en) * 2022-01-14 2022-05-06 中国石油大学(北京) Method for testing CTOD-delta a resistance curve of metal

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090119082A1 (en) * 2007-11-01 2009-05-07 Schlumberger Technology Corporation Reservoir fracture simulation
CN101968348A (en) * 2010-09-07 2011-02-09 中国石油大学(北京) Method for visually monitoring fracture crack
CN103266888A (en) * 2013-05-21 2013-08-28 中国石油大学(华东) System and method for visualization fracturing simulation experiment
CN103883301A (en) * 2014-03-31 2014-06-25 中国矿业大学 Physical simulation method of coal-bed gas well hydraulic fractures
CN105675724A (en) * 2016-01-29 2016-06-15 中国矿业大学 Acoustic emission positioning monitoring device and method for hydraulic fracturing fissure field of coal body containing gas
CN106442147A (en) * 2016-08-08 2017-02-22 温州大学 Steam or hydraulic fracturing consolidation test device
CN108535112A (en) * 2017-03-03 2018-09-14 中国石油化工股份有限公司 A kind of experiment analytical method for shale samples compressibility research
CN108732010A (en) * 2017-04-24 2018-11-02 中国石油天然气股份有限公司 A kind of simulation of fracturing fracture and evaluating apparatus and method
CN107893652A (en) * 2017-09-30 2018-04-10 中国石油大学(华东) The hydraulic fracturing analogue experiment installation and method of the enhanced geothermal system of hot dry rock
CN110924933A (en) * 2019-11-18 2020-03-27 中国石油集团川庆钻探工程有限公司 Visual experiment method for dynamically simulating shale fracturing fracture network
CN110987639A (en) * 2019-12-16 2020-04-10 重庆大学 Method for determining true triaxial hydraulic fracturing fracture expansion volume and fracture morphology by freezing method
CN113514337A (en) * 2020-04-09 2021-10-19 新奥科技发展有限公司 Hot dry rock rupture pressure test device and method
CN114441336A (en) * 2022-01-14 2022-05-06 中国石油大学(北京) Method for testing CTOD-delta a resistance curve of metal

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