阅读说明：本技术 一种可视化可变缝宽模拟自支撑压裂液流动规律的装置 (Visual device for simulating flow law of self-supporting fracturing fluid with variable seam width ) 是由 裴宇昕 廖兴松 张琼 周华兴 杨锋 *** 李海霞 任建芳 安宁 张津红 王树强 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种可视化可变缝宽模拟自支撑压裂液流动规律的装置,包括横向分布的主体框架(1)；主体框架的顶部开口,并且其中部具有一个中间空腔(1000)；中间空腔内用于放置模拟移动裂缝滑块(9)；主体框架的顶面开口上覆盖设置有钢化玻璃(7)；主体框架与一个底框(8)的顶部固定连接；主体框架)的正面左右两端,分别开有一个注液孔(2)和流出孔(3)；中间空腔的左边,设置有一个注入端内腔(13),注入端内腔与注液孔(2)相连通；中间空腔的右边,设置有流出端内腔(14),流出端内腔(14)与流出孔(3)相连通。本发明可以模拟自支撑压裂液体系流动与相变后形成的自支撑固相在地层裂缝内分布形态。(The invention discloses a device for simulating a flowing rule of self-supporting fracturing fluid by visual variable seam width, which comprises a main body framework (1) which is transversely distributed; the top of the main body frame is opened, and the middle part of the main body frame is provided with a middle cavity (1000); the middle cavity is used for placing a simulation moving crack sliding block (9); toughened glass (7) is covered on the opening on the top surface of the main body frame; the main body frame is fixedly connected with the top of a bottom frame (8); the left end and the right end of the front surface of the main body frame) are respectively provided with a liquid injection hole (2) and a liquid outlet hole (3); an injection end inner cavity (13) is arranged on the left side of the middle cavity and is communicated with the injection hole (2); an outflow end inner cavity (14) is arranged at the right side of the middle cavity, and the outflow end inner cavity (14) is communicated with the outflow hole (3). The invention can simulate the distribution form of the self-supporting solid phase formed after the flowing and phase change of the self-supporting fracturing fluid system in the stratum fracture.)

1. A device for visualizing the flow law of a variable-seam-width simulated self-supporting fracturing fluid is characterized by comprising a main body framework (1) which is transversely distributed;

the top of the main body frame (1) is opened, and the middle part of the main body frame is provided with a middle cavity (1000);

the middle cavity (1000) is used for placing a simulated moving crack sliding block (9);

the opening on the top surface of the main body frame (1) is covered with toughened glass (7);

the main body frame (1) is fixedly connected with the top of a bottom frame (8);

the left end and the right end of the front surface of the main body frame (1) are respectively provided with a liquid injection hole (2) and a flow-out hole (3);

an injection end inner cavity (13) is arranged on the left side of the middle cavity (1000), and the injection end inner cavity (13) is communicated with the injection hole (2);

an outflow end inner cavity (14) is arranged at the right side of the middle cavity (1000), and the outflow end inner cavity (14) is communicated with the outflow hole (3);

a first simulated perforation belt slope surface (151) is arranged between the left top edge of the middle cavity (1000) and the right top edge of the injection end cavity (13);

a first parallel slit surface (161) is formed between the top right edge of the middle cavity (1000) and the left top edge of the outlet cavity (14).

2. The apparatus for visualizing variable fracture width simulated self-standing fracture flow laws as in claim 1, wherein the first simulated perforation zone ramp surface (151) is a ramp shaped as high right and low left.

3. The apparatus for simulating the flow law of self-supporting fracturing fluids with variable visualized seam widths as claimed in claim 1, characterized in that the first parallel fracture surface (161) and the top surface of the body frame (1) are parallel to each other.

4. The device for simulating the flow law of the self-supporting fracturing fluid with the visual variable seam width as claimed in claim 1, wherein the front side and the rear side of the toughened glass (7) are respectively provided with a toughened glass fixing frame (17);

and the toughened glass fixing frame (17) is fixedly connected with the top surface of the main body frame (1).

5. The device for simulating the flow law of the self-supporting fracturing fluid with the visual variable seam width as claimed in claim 4, wherein the toughened glass fixing frame (17) is an L-shaped fixing frame.

6. The device for simulating the flow law of the self-supporting fracturing fluid with the visual variable gap width as claimed in claim 4, wherein the front side and the rear side of the top surface of the main body frame (1) are respectively provided with a plurality of mounting holes (101) which are distributed at intervals;

the toughened glass fixing frame (17) is provided with a threaded hole at the position corresponding to the mounting hole (101);

and the screws which are vertically distributed are respectively in threaded connection with the threaded holes and the mounting holes which vertically correspond to each other.

7. The device for simulating the flow law of the self-supporting fracturing fluid with the visual variable gap width as claimed in claim 6 is characterized in that the top of the main body frame (1) is provided with a circle of square groove at the inner side of the plurality of mounting holes (101), and an upper end face square sealing ring (10) is embedded in the groove;

the bottom surface of the main body frame (1) is provided with a circle of square groove, and the groove is used for embedding a square sealing ring (11) on the lower end surface.

8. The device for simulating the flowing law of the self-supporting fracturing fluid with the visual variable gap width as claimed in claim 1, wherein a fixed adjustable knob rack (4) is respectively arranged at the left end and the right end of the bottom surface of a bottom frame (8);

the central position of each fixed adjustable knob frame (4) and the bottom frame (8) corresponding to the central position are provided with vertically distributed adjustable knob connecting threaded holes;

the adjustable knob is connected with the threaded hole and is in threaded connection with the adjustable knobs (5) which are vertically distributed.

9. The device for simulating the flowing law of the self-supporting fracturing fluid with the visual variable gap width as claimed in claim 1 is characterized in that the bottom of the bottom frame (8) is respectively provided with a fixed pin connecting threaded hole at the left side and the right side of the two fixed adjustable knob frames (4);

the fixed pin connecting threaded hole vertically penetrates through the bottom frame (8);

each fixing pin connecting threaded hole is in threaded connection with one fixing pin (6).

10. The device for simulating the flow law of self-supporting fracturing fluids with variable visual gap width as claimed in any one of claims 1 to 9, wherein the simulation moving crack sliding block (9) is provided with embedded grooves distributed around the periphery of the lower part thereof;

an O-shaped sealing ring (12) is embedded in the embedding groove;

the lower part of the simulated moving crack sliding block (9) is contacted with the peripheral side wall of the middle cavity (1000) through an O-shaped sealing ring (12).

Technical Field

The invention relates to the field of oil exploitation, in particular to the field of oil and gas production yield increasing measures and processes, and particularly relates to a visual device capable of changing seam width and simulating a flowing rule of self-supporting fracturing fluid.

Background

At present, in the field of oil exploitation, the technical problems that the migration distance of slickwater carrying quartz sand is limited, the grain size of added sand is extremely small, and continuous operation cannot be generally performed exist in the conventional volume fracturing technology. A new hydraulic fracturing process is currently developed: liquid self-supporting fracturing techniques.

For the liquid self-supporting fracturing technology, the technical principle is as follows: the method comprises the following steps of pressing a stratum (or simultaneously matching with a conventional fracturing fluid and the like) by using an immiscible self-supporting fracturing fluid (which does not contain a solid phase at normal temperature, is a liquid with good flowing capability, has unique heat sensitivity, and generates a self-supporting solid phase when being heated to a certain temperature) and a channel fracturing fluid (which is a liquid which does not contain a solid phase and has good flowing capability at normal temperature, is a liquid which does not contain a solid phase and has good flowing capability, and has the functions of reducing filtration loss of the self-supporting fracturing fluid and controlling the distribution of the self-supporting fracturing fluid in the fracture so as to ensure that the self-supporting fracture with high flow conductivity is formed); meanwhile, the distribution of the formed self-supporting solid phase in the fracture is controlled by controlling the liquid property and the construction parameters of the channel fracturing fluid, so that the self-supporting fracture with high flow conductivity is formed, and the aim of improving the productivity of the oil-gas well is fulfilled. When the technology is matched with a volume fracturing technology for use, the effective transformation volume after volume fracturing can be effectively improved, the self-supporting solid phase can form large-particle-size supporting particles matched with the size of the fracture at the deepest part of the fracture, and the yield of the pressurized oil-gas well is greatly improved.

According to the principle of the self-supporting fracturing technology, in the process of forming a self-supporting solid phase with a certain shape and size by self-supporting fracturing, the self-supporting solid phase with different shapes and sizes can be formed due to the complex influence of parameters such as the formula of the self-supporting fracturing fluid and the channel fracturing fluid (which are combined to be called as a self-supporting fracturing fluid system), the proportion of two-phase fluid, the construction injection displacement and the like. And the self-supporting solid phases with different shapes and sizes have great difference in the flow conductivity of the formed self-supporting cracks.

Therefore, in order to guarantee the construction effect of the self-supporting fracturing technology, the experimental device for the flow distribution rule of the visual self-supporting fracturing fluid is researched and developed, and the experimental device has the necessity.

At present, the flow process of the self-supporting fracturing fluid system is divided into the following steps:

1. the self-supporting fracturing fluid and the channel fracturing fluid flow to a sand mixer from different ground fluid tanks through a ground flow pipeline (the flow pipeline is a low-pressure 3-inch or so thick pipeline on the ground);

2. after entering the sand mixing truck, the mixed sand flows out from a liquid suction pump (the rotating speed can reach 1450 revolutions per minute) at the outlet of the sand mixing truck after being sheared at high speed;

3. the oil is converged to a wellhead through a fracturing pry pipe after passing through a fracturing truck;

4. the mixture is injected into a casing, an oil pipe or an oil pipe casing through a wellhead Christmas tree (according to specific construction design);

5. through the perforated zone and into the formation fracture.

According to the basic principle of hydraulic fracturing, in the process of injecting self-supporting fracturing fluid into a stratum fracture by a high-discharge high-pumping pressure pump after the fracture is pressed open, the opening width of the stratum fracture is positively correlated with the static pressure in the stratum. The static pressure of fluid in the fracture is determined by construction discharge capacity and fluid loss rate, the self-supporting fracturing fluid is gradually heated by the stratum to raise the temperature and generate phase change to form a self-supporting solid phase at the later stage of construction, and at the moment, the self-supporting solid phase is finally extruded and fixed to a specific position of the fracture due to the fact that the width of the fluid loss fracture of the fracturing fluid is continuously reduced. Therefore, in order to ensure that the experimental device can simulate the distribution situation after the self-supporting solid phase solidification, the crack width must be adjustable. Meanwhile, the whole device needs to have the capability of resisting 10MPa pressure at the temperature of 150 ℃, and liquid is not leaked.

However, at present, there is no experimental device which can solve the above technical problems.

Disclosure of Invention

The invention aims to provide a device for simulating the flowing rule of self-supporting fracturing fluid by visual variable seam width aiming at the technical defects in the prior art.

Therefore, the invention provides a device for simulating the flowing law of self-supporting fracturing fluid by visual variable seam width, which comprises a main body framework which is transversely distributed;

the top of the main body frame is open, and the middle part of the main body frame is provided with a middle cavity;

the middle cavity is used for placing a sliding block for simulating the moving crack;

toughened glass is covered and arranged on the opening on the top surface of the main body frame;

the main body frame is fixedly connected with the top of a bottom frame;

the left end and the right end of the front surface of the main body frame are respectively provided with a liquid injection hole and a flow-out hole;

an injection end inner cavity is arranged on the left side of the middle cavity and communicated with the injection hole;

an outflow end inner cavity is arranged at the right side of the middle cavity and communicated with the outflow hole;

a first simulated perforation belt slope surface is arranged between the left top edge of the middle cavity and the right side edge of the top of the inner cavity of the injection end;

the middle cavity has a first parallel slit surface between the top right edge of the middle cavity and the top left edge of the outflow cavity.

The slope surface of the first simulated perforation belt is an inclined surface with the shape of a right side higher and a left side lower.

Wherein the first parallel crack surface is parallel to the top surface of the main body frame.

Wherein, the front side and the rear side of the toughened glass are respectively provided with a toughened glass fixing frame;

and the toughened glass fixing frame is fixedly connected with the top surface of the main body frame.

Wherein, the toughened glass mount is the mount of L type.

Wherein, the front side and the rear side of the top surface of the main body frame are respectively provided with a plurality of mounting holes which are distributed at intervals;

the toughened glass fixing frame is provided with a threaded hole at the position corresponding to the mounting hole;

and the screws which are vertically distributed are respectively in threaded connection with the threaded holes and the mounting holes which vertically correspond to each other.

The top of the main body frame is arranged on the inner side of the mounting holes and is provided with a circle of square groove, and a square sealing ring with an upper end surface is embedded in the groove;

the bottom surface of main body frame is provided with the square recess of round, and this recess is used for embedding terminal surface square seal circle down.

Wherein, the left end and the right end of the bottom surface of the bottom frame are respectively provided with a fixed adjustable knob frame;

the central position of each fixed adjustable knob frame and the bottom frame corresponding to the position are provided with vertically distributed adjustable knob connecting threaded holes;

the adjustable knob is connected with the threaded hole and is in threaded connection with the adjustable knobs which are vertically distributed.

The bottom of the bottom frame is provided with a fixed pin connecting threaded hole at the positions of the left side and the right side of the two fixed adjustable knob frames respectively;

the fixed pin connecting threaded hole vertically penetrates through the bottom frame;

each fixing pin connecting threaded hole is in threaded connection with one fixing pin.

The periphery of the lower part of the sliding block simulating the moving crack is provided with embedded grooves distributed in a surrounding manner;

an O-shaped sealing ring is embedded in the embedding groove;

the lower part of the sliding block for simulating the movement of the crack is contacted with the peripheral side wall of the middle cavity through an O-shaped sealing ring.

Compared with the prior art, the device for simulating the flowing rule of the self-supporting fracturing fluid with the visual variable seam width can simulate the distribution form of the self-supporting solid phase formed after flowing and phase changing of a self-supporting fracturing fluid system in a stratum fracture, and has great production practice significance.

According to the invention, the flow phenomenon of the self-supporting fracturing fluid system in the simulated perforation zone and the fracture can be visually observed in the liquid flowing process, then the self-supporting fracturing fluid system can be rapidly solidified in the fracture space, and finally the self-supporting solid phase is fixed in the fracture in situ by changing the fracture width and simulating the compression process of fracture extrusion, so that the high-flow-guide self-supporting fracture with a certain distribution rule can be formed. According to the invention, the flow law research can be carried out by researching the flow phenomenon of the self-supporting fracturing fluid system with different fluid properties and different construction parameters, and the flow law can be obtained to guide the formula research and the construction parameter design.

Drawings

Fig. 1a is a front view (front view) of a device for visualizing the flow law of a variable-gap simulated self-supporting fracturing fluid provided by the invention;

fig. 1b is a schematic overall three-dimensional structure diagram i of a device for simulating a flow law of a self-supporting fracturing fluid by using a visual variable gap width provided by the invention;

fig. 1c is a schematic overall three-dimensional structure diagram of a device for simulating a flow law of a self-supporting fracturing fluid with a variable visual gap width, provided by the invention;

FIG. 2 is a left side view of a device for visualizing flow laws of a variable-gap simulated self-supporting fracturing fluid provided by the invention;

fig. 3a is a top view of a main body frame in the device for visualizing the flow law of the self-supporting fracturing fluid simulated by the variable gap width provided by the invention;

fig. 3b is a schematic perspective structure diagram of a main body frame in the device for visualizing the flow law of the self-supporting fracturing fluid with variable gap width provided by the invention;

FIG. 4 is a bottom view of a main body frame in the device for visualizing the flow law of the self-supporting fracturing fluid simulated by the variable gap width provided by the invention;

fig. 5 is a bottom view of a bottom frame in the device for visualizing the flow law of the variable-gap simulated self-supporting fracturing fluid provided by the invention;

FIG. 6a is a front view of a simulated moving fracture sliding block in a device for visualizing a flow law of a variable-fracture-width simulated self-supporting fracturing fluid provided by the invention;

fig. 6b is a schematic perspective view of a simulated moving fracture sliding block in the device for visualizing the flow law of the self-supporting fracture fluid with variable fracture width provided by the invention;

fig. 7 is a top view of an upper end face square sealing ring in the device for visualizing the flow law of the self-supporting fracturing fluid with the variable gap width simulation provided by the invention;

fig. 8 is a top view of a lower end face square sealing ring in the device for visualizing the flow law of the self-supporting fracturing fluid with the variable gap width simulation provided by the invention;

fig. 9 is a top view of an O-ring in a device for visualizing a flow law of a variable gap width simulated self-supporting fracturing fluid provided by the invention;

fig. 10 is a picture taken by a camera of a shooting unit in the device for visualizing the flow law of the variable-gap simulated self-supporting fracturing fluid, which reflects the flow phenomenon of the self-supporting fracturing fluid system in the device for visualizing the flow law of the variable-gap simulated self-supporting fracturing fluid, wherein a transparent light-colored block in the picture is the self-supporting fracturing fluid.

Fig. 11 is a schematic structural diagram of a liquid supply and control unit in the device for simulating the flow law of the self-supporting fracturing fluid with a visual variable gap width provided by the invention;

in the figure: 1 is a main body frame, 2 is a liquid injection hole, 3 is a liquid outlet hole, 4 is a fixed adjustable knob frame, and 5 is an adjustable knob;

6 is a fixed pin, 7 is toughened glass, 8 is a bottom frame, 9 is a sliding block simulating moving cracks, and 10 is a square sealing ring with an upper end surface;

11 is a square sealing ring on the lower end surface, 12 is an O-shaped sealing ring, 13 is an injection end inner cavity, 14 is an outflow end inner cavity, 151 is a first simulated perforation belt slope surface, and 152 is a second simulated perforation belt slope surface;

161 is a first parallel crack surface, 162 is a second parallel crack surface, and 17 is a toughened glass fixing frame.

23 is a nitrogen gas cylinder, 24 is a pressure reducing valve,

25 is a six-way valve;

26 is a self-supporting fracturing fluid containing intermediate container, and 27 is a channel fracturing fluid containing intermediate container;

28 is a check valve;

Detailed Description

In order that those skilled in the art will better understand the technical solution of the present invention, the following detailed description of the present invention is provided in conjunction with the accompanying drawings and embodiments.

For the invention, it is firstly explained that when the self-supporting fracturing construction is carried out, the formed self-supporting fracture has higher flow conductivity, the key point is that the self-supporting fracturing fluid forms stable and effective support, and the flow form distribution of the self-supporting fracturing fluid system determines the distribution characteristics of the self-supporting solid phase after phase change, so that the research on the flow distribution rule of the self-supporting fracturing fluid system under different fluid formulas and different construction parameters is necessary for optimizing the self-supporting fracturing fluid formula and the self-supporting fracturing process design parameters.

The self-supporting fracturing fluid enters a shaft from a ground fluid tank through a pipeline on the ground, and the sectional area of a blast hole is the smallest in the process that the self-supporting fracturing fluid enters a fracture through the blast hole at the bottom of a well. The flow velocity of the fluid under the same displacement is inversely proportional to the flow cross-sectional area according to the judgment of a calculation formula of the flow velocity of the fluid. Therefore, the distribution rule of the self-supporting fracturing fluid system is greatly influenced by the blastholes and the blasthole zones. Through system research, the existing visual physical simulation experiment device capable of directly carrying out the distribution rule of the self-supporting fracturing fluid is quite a few, particularly the experiment device capable of simulating the gradual heating and temperature rise of the self-supporting fracturing fluid by the stratum to generate phase change to form a self-supporting solid phase and simulating the change of the width of the stratum fracture does not exist. Meanwhile, the fracturing technology needs to pump and inject a large amount of fracturing fluid under the high-discharge and high-pump pressure, so that when self-supporting fracturing fluid system injection simulation is carried out with high pump injection pressure and high discharge, the internal liquid pressure of the self-supporting fracturing fluid system injection simulation system greatly rises, and the device for simulating the flow law of the self-supporting fracturing fluid with good pressure resistance is researched and developed, and has important significance. Therefore, the present patent has made the following invention.

Referring to fig. 1 to 11, the device for visualizing the flow law of the self-supporting fracture fluid simulated by the variable fracture width provided by the invention comprises a main body frame 1 which is transversely distributed;

the top of the main frame 1 is open (i.e. the top surface is completely open), and the middle part of the main frame is provided with a middle cavity 1000 (the middle cavity, the upper end and the lower end of the middle cavity are open, the middle cavity is provided with a through hole which is communicated up and down, and only the cavity wall in the transverse horizontal peripheral direction is provided);

the middle cavity 1000 is used for placing horizontally distributed simulation moving crack sliding blocks 9;

the toughened glass 7 is covered on the opening on the top surface of the main body frame 1 (the middle cavity 1000 is covered on the inner side of the toughened glass 7);

the main body frame 1 is fixedly connected with the top of a bottom frame 8.

The left end and the right end of the front surface of the main body frame 1 are respectively provided with a liquid injection hole 2 and a liquid outlet hole 3;

an injection end inner cavity 13 (spaced from the middle cavity 1000) is arranged on the left side of the middle cavity 1000, and the injection end inner cavity 13 is communicated with the injection hole 2;

it should be noted that the injection end inner cavity 13 is communicated with the injection hole 3, and can provide an inflow passage of the self-supporting fracturing fluid.

An outflow end inner cavity 14 is arranged at the right side of the middle cavity 1000, (and is mutually separated from the middle cavity 1000), and the outflow end inner cavity 14 is communicated with the outflow hole 3;

it should be noted that the outlet end inner cavity 14 is communicated with the outlet hole 3, and can provide a fluid outlet channel for the self-supporting fracturing fluid.

A first simulated perforation ramp surface 151 is formed between the top left edge of the middle cavity 1000 and the top right edge of the injection end cavity 13;

the middle cavity 1000 has a first parallel fracture surface 161 between the top right edge of the middle cavity and the top left edge of the outlet cavity 14.

In the present invention, the slope 151 of the first simulated perforation zone is a steel surface, which is an inclined plane with a high right side and a low left side, and is used to simulate the flow pattern of the self-supporting fracturing fluid system in the conical perforation zone.

In the present invention, the first parallel slit surface 161 is a steel surface, which is parallel to the top surface (i.e., the upper end surface) of the main body frame 1.

In the invention, in the concrete implementation, the front side and the rear side of the toughened glass 7 are respectively provided with a toughened glass fixing frame 17;

and the toughened glass fixing frame 17 is fixedly connected with the top surface of the main body frame 1.

In particular, the tempered glass fixing frame 17 is an L-shaped fixing frame.

In the concrete realization, between toughened glass mount 17 and main body frame 1's the top surface, concrete connection structure is: the front side and the rear side of the top surface of the main body frame 1 are respectively provided with a plurality of mounting holes 101 which are distributed at intervals;

the toughened glass fixing frame 17 is provided with a threaded hole at a position corresponding to the mounting hole 101;

and the screws which are vertically distributed are respectively in threaded connection with the threaded holes and the mounting holes which vertically correspond to each other.

In the concrete implementation, the top of the main body frame 1 is provided with a circle of square grooves at the inner sides of the plurality of mounting holes 101, and the upper end face square sealing rings 10 are embedded in the grooves.

In the present invention, in a specific implementation, the main frame 1 and the bottom frame 8 are fixedly connected by six bolts.

In the concrete implementation, the bottom surface of the main body frame 1 is provided with a circle of square groove, and the groove is used for embedding the lower end surface square sealing ring 11.

In the invention, in concrete implementation, the left end and the right end of the bottom surface of the bottom frame 8 are respectively provided with a fixed adjustable knob frame 4 which is vertically distributed;

the central position of each fixed adjustable knob frame 4 and the bottom frame 8 corresponding to the central position are provided with an adjustable knob connecting threaded hole which is vertically distributed (the adjustable knob connecting threaded hole vertically penetrates through the bottom frame 8 and the fixed adjustable knob frame 4);

the adjustable knob is connected with the threaded hole and is in threaded connection with the adjustable knobs 5 which are vertically distributed (the outer walls of the upper parts of the adjustable knobs 5 are provided with external threads).

That is, the middle of the fixed adjustable knob frame 4 is provided with threads matched with the adjustable knob 5 for rotation. The adjustable knob can be rotated at the bottom of the back frame 8 to adjust the length of the upper end of the adjustable knob extending into the middle cavity 1000 above the back frame 8.

In particular, the bottom of the bottom frame 8 is respectively provided with a fixed pin connecting threaded hole at the left side and the right side of the two fixed adjustable knob frames 4;

the fixed pin connecting threaded hole vertically penetrates through the bottom frame 8;

each fixing pin connecting threaded hole is threadedly connected with one fixing pin 6.

Therefore, the fixing pin 6 can rotate at the bottom of the bottom frame 8, and adjust the length of the upper end part extending into the middle cavity 1000 above the bottom frame 8.

In the invention, in the concrete implementation, the periphery of the lower part of the simulated moving crack sliding block 9 is provided with embedded grooves distributed in a surrounding way;

an O-shaped sealing ring 12 is embedded in the embedding groove;

the lower part of the simulated moving crack sliding block 9 is contacted with the peripheral side wall of the middle cavity 1000 through an O-shaped sealing ring 12.

Therefore, the analog movement crack sliding block 9 is fixed on the middle cavity 10 of the main body frame 1 through the O-shaped sealing ring 12, the bottom surface of the analog movement crack sliding block 9 is vertically contacted with the top of the adjustable knob 5 and the top of the fixed pin 6 which extend into the middle cavity 10, wherein, the analog movement crack sliding block 9 can move up and down in the middle cavity 10 along the vertical direction by rotating the two adjustable knobs 5, and the stability (namely horizontal support) of the analog movement crack sliding block 9 in the middle cavity 10 can be ensured through the fixed pin 6.

In the invention, the width of the simulated fracture in the vertical direction can be adjusted by simulating the up-and-down movement of the movable fracture sliding block 9 in the middle cavity 10 along the vertical direction, so that the influence of different fracture widths on the flow distribution of the self-supporting fracturing fluid can be simulated.

In a specific implementation, referring to fig. 6, the left side of the top surface of the simulated moving fracture sliding block 9 is provided with a second simulated perforation belt slope surface 152 connected with the right end of the first simulated perforation belt slope surface 151;

the simulation moving crack slider 9 has a second parallel crack surface 162 on the right side of the top surface, and is connected to the right end of the first parallel crack surface 161.

It should be noted that the second simulated perforation belt slope 152 is also a steel surface, which is a slope with a high right side and a low left side, and is used to simulate the flow pattern of the self-supporting fracturing fluid system in the conical shaped perforation belt. The second parallel slit surface 162 is also a steel surface which is parallel to the top surface (i.e., the upper end surface) of the body frame 1.

In the invention, the toughened glass 7 is made of high-strength toughened fireproof glass, does not deform or crack at the temperature of 180 ℃ and resists the fluid pressure of 10MPa inside.

In the present invention, the upper end face square seal ring 10, the lower end face square seal ring 11, and the O-ring 12 are made of organic acid-resistant and strong acid-resistant materials such as fluorine-containing or polytetrafluoroethylene rubber.

In the invention, the main body frame 1, the fixed adjustable knob frame 4, the adjustable knob 5, the fixed pin 6, the bottom frame 8 and the simulated moving crack sliding block 9 are all made of carburizing steel, are strengthened by quenching for 3 times after processing, and are subjected to phosphating treatment on the surface, so that the invention has excellent performances of water resistance, organic solvent resistance, strong acid resistance and strong alkali resistance.

It should be noted that the blasthole refers to: the perforating bullet is detonated at a corresponding depth of the shaft and enters the stratum, so that the shaft is communicated with a stratum fracture, a channel for oil gas to flow from the stratum to the shaft is formed, the shape of the channel is cylindrical, the diameter of the channel is within the range of 1-10 CM, and the length of the channel is 1-several meters.

According to the invention, the corresponding parts of the experimental device are reduced in equal proportion according to the sizes of the actual shaft and the actual crack. To simulate the shear behavior of an actual borehole, the borehole is sized to coincide with a borehole in the actual formation, since the cross-sectional flow area at the simulated borehole is much smaller than the wellbore and fracture.

In the present invention, the perforated band is a flow channel formed in the formation after perforations are ejected through the wellbore wall and through the formation. The perforation belt in the patent is processed into a corresponding shape according to the shape and the angle of the perforation belt so as to simulate the flowing process of self-supporting fracturing fluid in the perforation belt.

It should be noted that hydraulic fracturing, fracturing for short, refers to a process of fracturing a rock under high pressure by injecting a fracturing fluid and generating a fracture, the length of the generated fracture ranges from tens of meters to hundreds of meters, the height ranges from tens of meters to tens of meters, and the width is within twenty millimeters,

in the device of this patent, utilize the toughened glass who processes to realize end face seal through the sealing washer, inside forms a parallel crack passageway, and then realizes simulating the shearing action of crack to liquid flow.

Based on the technical scheme, the basic components are combined together to form the visual variable-crack-width simulation self-supporting fracturing fluid flow law device, and a continuous closed visual flow channel which can resist 10MPa of liquid pressure, can simulate a perforation zone and can change the crack width in the experimental process is formed in the device.

In the present invention, the outlet 3 is connected to a hollow waste liquid collecting container (for example, a hollow rectangular sealed container) through a hollow connecting pipe.

In the invention, the injection hole 2 is respectively communicated with a container for storing the self-supporting fracturing fluid and a container for storing the channel fracturing fluid in advance through two hollow connecting pipelines. According to the needs of users, liquid pumps (water pumps) can be respectively arranged on the two connecting pipelines.

In the invention, the liquid injection hole 2 can be communicated with a liquid supply pressure control unit;

and the liquid supply and pressure control unit is used for supplying self-supporting fracturing liquid and channel fracturing liquid to the interior of the main body frame 1 through the liquid injection hole 2.

In particular, the liquid supply and pressure control unit specifically comprises two nitrogen cylinders 23;

the gas outlets of the two nitrogen gas cylinders 23 are respectively communicated with the top gas inlets of the self-supporting fracturing fluid containing intermediate container 26 and the channel fracturing fluid containing intermediate container 27 through a hollow connecting pipeline;

a self-supporting fracturing fluid holding intermediate container 26 communicated with one end of the self-supporting fracturing fluid injection pipe 291;

a channel fracturing fluid holding intermediate container 27 communicated with one end of the channel fracturing fluid injection pipe 292;

the self-supporting fracturing fluid injection pipe 291 and the other end of the channel fracturing fluid injection pipe 292 are communicated with the injection hole 2 on the main body frame 1 after confluence.

In particular, the self-supporting fracturing fluid injection pipe 291 and the channel fracturing fluid injection pipe 292 are respectively provided with a check valve (i.e., a check valve) 28.

In particular, a pressure reducing valve 24 and a six-way valve 25 are arranged on a connecting pipeline between a self-supporting fracturing fluid containing intermediate container 26 and a gas outlet of a nitrogen gas cylinder 23;

a pressure reducing valve 24 and a six-way valve 25 are also arranged on a connecting pipeline between the channel fracturing fluid containing intermediate container 27 and the gas outlet of the nitrogen gas cylinder 23;

each six-way valve 25 is connected to a pressure gauge 250.

It should be noted that, with the present invention, the nitrogen gas cylinder 23 can stably provide a liquid injection pressure of up to 12MPa, and ensure that the self-supporting fracturing fluid holding intermediate container 26 and the channel fracturing fluid holding intermediate container 27 can provide a sufficient liquid injection pressure when outputting the self-supporting fracturing fluid and the channel fracturing fluid outwards.

In concrete implementation, a pressure reducing valve 24 is connected to the nitrogen gas cylinder 23, and the device can reduce the inlet pressure to a certain required outlet pressure and automatically keep the outlet pressure stable by means of the energy of the medium (as shown in fig. 11).

It should be noted that, for the present invention, the six-way valve 25 and the pressure gauge 250 may be combined together to form an integrated pressure control unit, which may be used to respectively read the respective injection pressures of the self-supporting fracturing fluid and the channel fracturing fluid, and the injection flow control of the self-supporting fracturing fluid and the channel fracturing fluid may be realized by the opening degrees of the switches after the pressure reducing valve 24 and the six-way valve 25. In particular, the switch on the six-way valve can be used for pressure relief after the experiment is finished (as shown in fig. 11).

In a specific implementation, the system further comprises a shooting unit, specifically comprising a camera;

the camera is positioned right above the toughened glass 7;

the lens of the camera faces the top surface of the toughened glass 7.

It should be noted that, in the present invention, when the imaging unit is used as an image acquisition device to observe the high-speed dynamic flow of the self-supporting fracturing fluid system, it is necessary to perform imaging with a camera or a video recorder having a high pixel and high sensitivity in a full-frame level or above, and the dynamic flow and static distribution of the self-supporting fracturing fluid system in the main body frame 1 under the tempered glass 7 can be clearly recorded through the tempered glass 7.

For a more clear understanding of the present invention, the following description is made with respect to a specific assembly process of the present invention as follows:

1. the upper end face square seal ring 10 and the lower end face square seal ring 11 are respectively installed in the inner grooves at the upper end and the lower end of the main body frame 1. And plugging the O-shaped sealing ring 12 into a corresponding caulking groove at the lower part of the simulation moving crack sliding block 9.

2. The simulated moving crack sliding block 9 with the assembled O-shaped sealing ring is parallel to the upper end surface and the lower end surface of the main body frame 1 and is arranged in the middle inner cavity of the main body frame 1. The bottom frame 8 is mounted below the main body frame 1 by screws.

3. Two fixed adjustable knob frames 4 are installed on corresponding hole positions of the bottom frame 8, then the adjustable knobs 5 are screwed in through threads inside the fixed adjustable knob frames 4, the two adjustable knobs 5 are kept to rotate simultaneously, and therefore the fact that the simulated moving crack sliding blocks 9 contacted with the tops of the adjustable knobs 5 move parallel to the upper end face of the main body frame 1 is guaranteed. And screwing the fixing pin 6 into the corresponding hole on the bottom frame 8, so that the fixing pin is simultaneously contacted with the bottom surface of the simulation moving crack slide block 9.

4. Mounting toughened glass 7 at a corresponding position through a toughened glass fixing frame 7;

5. finally, the liquid injection hole 2 and the liquid outlet hole 3 are connected with pipelines (namely an input pipeline and an output pipeline of the mixed liquid of the self-supporting fracturing liquid and the channel fracturing liquid) with corresponding sizes, and then the experiment can be started.

It should be noted that the whole device shown in fig. 1 of the present invention can be placed in a preheated liquid (e.g. hot water), and the whole device (specifically, the self-supporting fracturing fluid flowing through the inside of the main body frame 1) can be heated by the high temperature conducted by the external liquid, so that the self-supporting fracturing fluid can be heated, and then forms a self-supporting solid phase after the phase change.

For a more clear understanding of the invention, reference is now made to the following specific examples:

the flowing process of the self-supporting fracturing fluid system in the device for simulating the flowing rule of the self-supporting fracturing fluid with the visual variable seam width is as follows:

firstly, self-supporting fracturing fluid and channel fracturing fluid are respectively displaced by different nitrogen bottles and fluid tanks, enter the middle cavity of the inner wall of the main body frame 1 through the fluid injection hole, and then pass through the simulated perforation zone slope 15 and the outflow end plane 16 under the action of fluid pressure, and in the process, after the self-supporting fracturing fluid is sheared by the perforation zone and the parallel space, the distribution form is shown in fig. 10 (transparent light-colored blocks are self-supporting fracturing fluid in the drawing).

Compared with the prior art, the device for simulating the flow law of the self-supporting fracturing fluid with the visual variable seam width has the following beneficial technical effects:

1. according to different experimental parameters and the uniquely designed conical flowing space, the distribution influence of a perforation zone on the self-supporting fracturing fluid can be simulated.

2. The flow phenomenon of self-supporting fracturing fluid systems with different densities, surface tensions and viscosities in fractures with different widths can be simulated under different stratum temperatures, pressures and injection displacement, and further the formula, construction parameters and process of the self-supporting fracturing fluid and the channel fracturing fluid are optimized.

3. The width of the crack can be adjusted in the experimental process, the change process of the crack in the fracturing construction process can be simulated, and the real distribution form of the self-supporting solid phase in the actual crack is maintained.

4. The device can inject strong acid or strong alkaline fluid and corrosive organic solvent, has wide application range, and can simulate the flowing phenomenon of self-supporting fracturing fluid and different kinds of channel fracturing fluid.

5. The device adopts end face sealing, the internal fluid pressure can reach 5MPa, the requirements of high injection pressure and large-displacement pumping are met, and the device is more close to the site simulation construction conditions.

6. The device has the advantages of relatively simple processing of all components and strong operability.

7. The device of the invention is detachable and washable, convenient to assemble, simple to operate and strong in practicability.

In summary, compared with the prior art, the device for simulating the flow law of the self-supporting fracturing fluid by the visual variable fracture width, which is provided by the invention, can simulate the distribution form of the self-supporting solid phase formed after the flow and phase change of the self-supporting fracturing fluid system in the formation fracture, and has great production practice significance.

According to the invention, the flow phenomenon of the self-supporting fracturing fluid system in the simulated perforation zone and the fracture can be visually observed in the liquid flowing process, then the self-supporting fracturing fluid system can be rapidly solidified in the fracture space, and finally the self-supporting solid phase is fixed in the fracture in situ by changing the fracture width and simulating the compression process of fracture extrusion, so that the high-flow-guide self-supporting fracture with a certain distribution rule can be formed. According to the invention, the flow law research can be carried out by researching the flow phenomenon of the self-supporting fracturing fluid system with different fluid properties and different construction parameters, and the flow law can be obtained to guide the formula research and the construction parameter design.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.