CN111458457A - Visual simulation device for sand carrying and sand laying of carbon dioxide fracturing fluid and evaluation method - Google Patents
Visual simulation device for sand carrying and sand laying of carbon dioxide fracturing fluid and evaluation method Download PDFInfo
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- CN111458457A CN111458457A CN202010291620.0A CN202010291620A CN111458457A CN 111458457 A CN111458457 A CN 111458457A CN 202010291620 A CN202010291620 A CN 202010291620A CN 111458457 A CN111458457 A CN 111458457A
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- 239000012530 fluid Substances 0.000 title claims abstract description 136
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 84
- 239000004576 sand Substances 0.000 title claims abstract description 72
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 47
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 43
- 238000004088 simulation Methods 0.000 title claims abstract description 31
- 230000000007 visual effect Effects 0.000 title claims abstract description 24
- 238000011156 evaluation Methods 0.000 title claims abstract description 12
- 238000002347 injection Methods 0.000 claims abstract description 126
- 239000007924 injection Substances 0.000 claims abstract description 126
- 230000007246 mechanism Effects 0.000 claims abstract description 38
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 8
- 239000007789 gas Substances 0.000 claims description 80
- 239000007788 liquid Substances 0.000 claims description 66
- 238000000926 separation method Methods 0.000 claims description 43
- 238000011084 recovery Methods 0.000 claims description 32
- 239000007787 solid Substances 0.000 claims description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 230000000087 stabilizing effect Effects 0.000 claims description 5
- 238000005057 refrigeration Methods 0.000 claims description 4
- 230000007480 spreading Effects 0.000 claims description 4
- 238000001556 precipitation Methods 0.000 claims 3
- 239000000203 mixture Substances 0.000 abstract description 14
- 230000008859 change Effects 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 239000002245 particle Substances 0.000 description 37
- 230000005012 migration Effects 0.000 description 7
- 238000013508 migration Methods 0.000 description 7
- 230000001133 acceleration Effects 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 5
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Abstract
The invention discloses a carbon dioxide fracturing fluid sand carrying and sand laying visual simulation device and an evaluation method, wherein the simulation device comprises a simulation mechanism and an injection mechanism, the simulation mechanism comprises a crack model combination, the crack model combination comprises a plurality of crack models and connecting pipes, each crack model is provided with a crack cavity, and the crack cavities are communicated through the connecting pipes to form a crack net cavity; the injection mechanism includes injection pipe, gas injection device, notes sand device and notes fracturing fluid device, and the gas injection device is used for letting in carbon dioxide gas in to the injection pipe, annotates sand device and is used for injecting into the proppant in the injection pipe, annotates fracturing fluid device and is used for injecting into fracturing fluid in the injection pipe. The technical scheme provided by the invention has the beneficial effects that: the actual reservoir fractures are simulated through the fracture model combination, and the mixture of carbon dioxide gas, the propping agent and the fracturing fluid is injected into the fracture model combination through the injection mechanism, so that the sand carrying and laying characteristics and the change rule of the fracturing fluid are researched.
Description
Technical Field
The invention relates to the technical field of petroleum development, in particular to a carbon dioxide fracturing fluid sand carrying and laying visual simulation device and an evaluation method.
Background
During the course of the fracturing fluid entering the fracture through the wellbore, the proppant settles. At present, supercritical CO2The research on the sand carrying and spreading characteristics of the fracturing fluid adopts a high-pressure static sand suspension experiment system, and mainly tests that the proppant particles are supported in supercritical CO under different experiment conditions2Sedimentation velocity in fracturing fluid system, the sedimentation law of proppant in the direction of the sedimentation velocity of particles is studied, but with regard to supercritical CO2The characteristics of sand carrying and spreading such as the settling rule and the migration condition of the fracturing fluid carrying the proppant in the fracture are rarely researched. The sedimentation, migration rule and distribution condition of the fracturing fluid carrying the propping agent in the fracture directly affect the geometric size, flow conductivity and fracturing efficiency of the sand-filled fracture, so that the application value of the fracturing fluid can be embodied only by researching the sand-carrying and sand-laying characteristics and the change rule of the fracturing fluid.
Disclosure of Invention
In view of the above, a need exists for a method that can effectively demonstrate the sand-carrying and sand-laying processes of a fracturing fluid, so as to study the sand-carrying and sand-laying characteristics of the fracturing fluid and the change rule thereof, and to better evaluate the performance of the fracturing fluid.
The invention provides a carbon dioxide fracturing fluid sand carrying and laying visual simulation device, which comprises: a simulation mechanism and an injection mechanism, wherein,
the simulation mechanism comprises a crack model combination, the crack model combination comprises a plurality of crack models and connecting pipes, each crack model is provided with a crack cavity, and the crack cavities are communicated through the connecting pipes to form a crack network cavity;
the injection mechanism includes injection pipe, gas injection device, notes sand device and notes fracturing fluid device, the injection pipe with the one end intercommunication of fracture net cavity, the gas injection device with the injection union coupling and be used for to let in carbon dioxide gas in the injection pipe, annotate the sand device with the injection union coupling and be used for to inject into the proppant in the injection pipe, annotate the fracturing fluid device with the injection union coupling and be used for to inject into fracturing fluid in the injection pipe.
The invention also provides a visual evaluation method for sand carrying and sand laying of the carbon dioxide fracturing fluid, which is suitable for the visual simulation device for sand carrying and sand laying of the carbon dioxide fracturing fluid, and comprises the following steps:
s1, obtaining the average diameter and density of the proppant to be used, and obtaining the density of the sand-carrying fluid to be used under the conditions of preset temperature and preset pressure;
s2, injecting the propping agent and the sand-carrying liquid into an injection pipe through the sand injection device;
s3, injecting carbon dioxide gas into the injection pipe through the gas injection device;
s4, injecting fracturing fluid to be evaluated into the injection pipe through the fracturing fluid injection device;
and S5, evaluating the performance of the fracturing fluid according to a preset evaluation standard.
Compared with the prior art, the technical scheme provided by the invention has the beneficial effects that: the actual reservoir fractures are simulated through the fracture model combination, and the mixture of carbon dioxide gas, the propping agent and the fracturing fluid is injected into the fracture model combination through the injection mechanism, so that the sand carrying and laying characteristics and the change rule of the fracturing fluid are researched, and the fracturing performance of the propping agent is evaluated.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device and an evaluation method provided by the invention;
FIG. 2 is a schematic diagram of the simulation mechanism of FIG. 1;
FIG. 3 is a schematic structural view of the gas injection apparatus in FIG. 1;
FIG. 4 is a schematic structural view of the sand injection apparatus of FIG. 1;
FIG. 5 is a schematic diagram of the fracturing fluid injection apparatus of FIG. 1;
FIG. 6 is a schematic view of the separation and recovery mechanism of FIG. 1;
FIG. 7 is a front view of the fracture model of FIG. 1;
FIG. 8 is a side view of the fracture model of FIG. 7;
FIG. 9 is a cross-sectional view of the fracture model of FIG. 8 at section A-A;
in the figure: 1-simulation mechanism, 2-injection mechanism, 4-separation recovery mechanism, 11-crack model, 111-crack cavity, 112-transparent window, 12-connecting pipe, 21-injection pipe, 22-gas injection device, 221-carbon dioxide gas tank, 222-gas storage tank, 223-gas injection pump, 224-refrigerating unit, 225-first filter, 23-sand injection device, 231-sand storage tank, 232-propeller, 24-fracturing fluid injection device, 241-fracturing fluid storage tank, 242-fracturing fluid propulsion device, 2421-water tank, 2422-electronic balance, 2423-fracturing fluid injection pump, 31-heater, 32-temperature sensor, 41-discharge pipe, 42-solid separation component, 421-solid separation tank, 422-liquid outlet pipe, 423-second filter, 43-gas-liquid separation component, 431-gas-liquid separation tank, 432-gas outlet pipe, 44-pressure stabilizing component, 441-back pressure valve, 442-nitrogen tank, 45-gas recovery component, 451-gas recovery pipe, 452-one-way valve, 46-liquid recovery component, 461-liquid recovery pipe and 462-liquid recovery tank.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1 to 6, the invention provides a carbon dioxide fracturing fluid sand carrying and laying visual simulation device, which comprises a simulation mechanism 1 and an injection mechanism 2.
Referring to fig. 2, 7-9, the simulation mechanism 1 includes a fracture model assembly, the fracture model assembly includes a plurality of fracture models 11 and connecting pipes 12, each fracture model 11 has a fracture cavity 111, and each fracture cavity 111 is communicated through the connecting pipe 12 to form a fracture network cavity. By combining a plurality of fracture models 11, fracture network cavities with different shapes are formed so as to simulate different fracture types. The crack model 11 is provided with a transparent window 112, and a crack cavity 111 in the crack model 11 can be observed through the transparent window 112, so that the observation of the sand carrying and spreading processes of the carbon dioxide fracturing fluid is facilitated.
Referring to fig. 1, the injection mechanism 2 includes an injection pipe 21, a gas injection device 22, a sand injection device 23, and a fracturing fluid injection device 24, the injection pipe 21 is communicated with one end of the fracture network cavity, the gas injection device 22 is connected to the injection pipe 21 and is used for introducing carbon dioxide gas into the injection pipe 21, the sand injection device 23 is connected to the injection pipe 21 and is used for injecting proppant into the injection pipe 21, and the fracturing fluid injection device 24 is connected to the injection pipe 21 and is used for injecting fracturing fluid into the injection pipe 21.
Specifically, referring to fig. 3, the gas injection device 22 includes a carbon dioxide tank 221, a gas storage tank 222 and a gas injection pump 223, wherein the carbon dioxide tank 221 has a first gas storage cavity; the gas storage tank 222 is provided with a closed second gas storage cavity, and the second gas storage cavity is communicated with the first gas storage cavity; the inlet of the air injection pump 223 is communicated with the second air storage cavity, and the outlet of the air injection pump 223 is communicated with the injection pipe 21. In use, CO in the carbon dioxide gas tank 2212The gas first enters the gas container 222 and then enters the injection pipe 21 through the gas injection pump 223.
Preferably, referring to fig. 3, the gas injection device 22 further includes a refrigerator set 224, and the refrigerator set 224 is disposed in the second gas storage cavity. The refrigeration unit 224 is used for supplying CO in the gas storage tank 2222The gas is cooled to make CO in the gas storage tank 2222The gas liquefies. In this embodiment, the first filter 225 is disposed on the communication channel between the second gas storage cavity and the first gas storage cavity, so as to filter out CO2Impurities in the gas.
Specifically, referring to fig. 4, the sand injection device 23 includes a sand storage tank 231 and a propeller 232, wherein the sand storage tank 231 has a closed sand storage cavity; the inlet of the propeller 232 is communicated with the sand storage cavity, and the outlet of the propeller 232 is communicated with the injection pipe 21. In this embodiment, the number of the sand storage tanks 231 is two, and when the sand storage tank 231 is used, the proppant and the sand-carrying liquid are added into the sand storage tank 231, and the pusher 232 pushes the proppant and the sand-carrying liquid of the sand storage tank 231 into the injection pipe 21, and then receives the sand-carrying liquidTo the injection pipe 21 of high pressure CO2The gas drives the proppant and sand-carrying fluid into the fracture model 11.
Specifically, referring to fig. 5, the fracturing fluid injection device 24 includes a fracturing fluid storage tank 241 and a fracturing fluid propelling device 242, the fracturing fluid storage tank 241 has a closed fracturing fluid storage cavity, and the fracturing fluid storage cavity is communicated with the injection pipe 21; the fracturing fluid propelling device 242 is connected with the fracturing fluid storage tank 241 and is used for propelling the fracturing fluid in the fracturing fluid storage cavity into the injection pipe 21.
Preferably, referring to fig. 5, the fracturing fluid propelling device 242 includes a water tank 2421, an electronic balance 2422 and a fracturing fluid injection pump 2423, the water tank 2421 has a closed water storage cavity, and the water tank 2421 is disposed on the electronic balance 2422; the inlet of the fracturing fluid injection pump 2423 is communicated with the water storage cavity, and the outlet of the fracturing fluid injection pump 2423 is communicated with the fracturing fluid storage cavity. When the fracturing fluid injection pump 2423 is used, water in the water tank 2421 is injected into the fracturing fluid storage tank 241 through the fracturing fluid injection pump 2423, so that the fracturing fluid in the fracturing fluid storage tank 241 is pushed into the injection pipe 21, the reduction amount of the water in the water tank 2421 can be measured through the electronic balance 2422, the reduction amount of the water in the water tank 2421 is equal to the amount of the fracturing fluid entering the injection pipe 21, and therefore the injection amount of the fracturing fluid can be quantitatively controlled.
Specifically, referring to fig. 1, the visual simulation device for sand carrying and sand laying of the carbon dioxide fracturing fluid further comprises a temperature control mechanism, wherein the temperature control mechanism comprises a heater 31 and a temperature sensor 32, and both the heater 31 and the temperature sensor 32 are arranged in the injection pipe 21. In use, the mixture in the injection pipe 21 is heated by the heater 31, and when the temperature sensor 32 detects that the temperature of the mixture in the injection pipe 21 reaches a preset temperature, the heater 31 stops heating, and the temperature of the mixture in the injection pipe 21 is maintained at the preset temperature by controlling the on or off of the heater 31.
Specifically, referring to fig. 6, the visual simulation device for sand carrying and sand laying of the carbon dioxide fracturing fluid further comprises a separation and recovery mechanism 4, wherein the separation and recovery mechanism 4 comprises a discharge pipe 41, a solid separation assembly 42 and a gas-liquid separation assembly 43, and one end of the discharge pipe 41 is communicated with the other end of the fracture net cavity.
Referring to fig. 6, the solid separating assembly 42 includes a solid separating tank 421 and a liquid outlet pipe 422, the solid separating tank 421 has a closed solid deposition cavity, the solid deposition cavity is communicated with the other end of the liquid outlet pipe 41, and the liquid outlet pipe 422 is communicated with the solid deposition cavity. In this embodiment, the two solid separation tanks 421 are provided in series, thereby enhancing the solid separation effect. In addition, to prevent small amounts of solids from flowing out with the liquid, a second filter 423 is provided within effluent pipe 422 to block the passage of proppant particles. In use, proppant particles in the mixture settle in solids separation tank 421 and liquid in the mixture flows out through effluent pipe 422.
Referring to fig. 6, the gas-liquid separation assembly 43 includes a gas-liquid separation tank 431 and a gas outlet pipe 432, the gas-liquid separation tank 431 has a sealed gas-liquid separation chamber, and the gas outlet pipe 432 is communicated with the gas-liquid separation chamber. In use, the gas-liquid mixture flowing out of the liquid outlet pipe 422 enters the gas-liquid separation tank 431, the gas in the gas-liquid mixture is led out from the gas outlet pipe 432, the liquid in the gas-liquid mixture is stored in the gas-liquid separation tank 431, and when the liquid in the gas-liquid separation tank 431 reaches a certain amount, the liquid in the gas-liquid separation tank 431 is discharged to prevent the gas-liquid separation tank 431 from being filled.
Preferably, referring to fig. 6, the separation and recovery mechanism 4 further includes a pressure stabilizing assembly 44, the pressure stabilizing assembly 44 includes a backpressure valve 441 and a nitrogen tank 442, an inlet of the backpressure valve 441 is communicated with the liquid outlet pipe 422, and an outlet of the backpressure valve 441 is communicated with the gas-liquid separation chamber; the outlet of the nitrogen tank 442 communicates with the pressure input of the backpressure valve 441. In this embodiment, the back pressure valve 441 is a pneumatic back pressure valve, and the nitrogen gas in the nitrogen tank 442 is used as a power source of the back pressure valve 441, and when in use, the opening pressure of the back pressure valve 441 is controlled by controlling the output amount of the nitrogen gas in the nitrogen tank 442, so that the pressure in the fracture model 11 is kept stable, and the pressure in the gas-liquid separation tank 431 is rapidly reduced to the normal pressure, so that the nitrogen gas is converted into a gaseous state and discharged from the gas outlet pipe 432.
Preferably, referring to fig. 1, the separation and recovery mechanism 4 further includes a gas recovery assembly 45, the gas recovery assembly 45 includes a gas recovery pipe 451 and a one-way valve 452, one end of the gas recovery pipe 451 is communicated with the gas outlet pipe 432, the other end of the gas recovery pipe 451 is communicated with the first gas storage chamber, and the one-way valve 452 is disposed on the gas recovery pipe 451, so as to prevent the mixture injected into the pipe 21 from flowing backwards into the gas recovery pipe 451.
Preferably, referring to fig. 1, the separation and recovery mechanism 4 further includes a liquid recovery assembly 46, the liquid recovery assembly 46 includes a liquid recovery tube 461 and a liquid recovery tank 462, one end of the liquid recovery tube 461 is communicated with the gas-liquid separation chamber, the liquid recovery tank 462 has a liquid recovery chamber, the liquid recovery chamber is communicated with the other end of the liquid recovery tube 461, and the liquid recovery chamber is further communicated with the injection tube 21.
The invention also provides a visual evaluation method for sand carrying and sand laying of the carbon dioxide fracturing fluid, which is suitable for the visual simulation device for sand carrying and sand laying of the carbon dioxide fracturing fluid, and comprises the following steps:
s1, obtaining the average diameter and density of the proppant to be used, and obtaining the density of the sand-carrying fluid to be used under the conditions of preset temperature and preset pressure;
s2, filling the proppant and the sand-carrying liquid into a sand storage tank 231, opening a propeller 232, and injecting the proppant and the sand-carrying liquid into an injection pipe 21 through the sand injection device 23;
s3, opening the carbon dioxide gas tank 221, the gas injection pump 223 and the refrigeration unit 224, and injecting carbon dioxide gas into the injection pipe 21 through the gas injection device 22;
s4, opening a fracturing fluid injection pump 2423, injecting the fracturing fluid to be evaluated into the injection pipe 21 through the fracturing fluid injection device 24, opening the heater 31 to enable the temperature of the mixture in the injection pipe 21 to reach a preset temperature, and closing the carbon dioxide gas tank 221 when the pressure of the mixture in the injection pipe 21 reaches a preset pressure;
and S5, evaluating the performance of the fracturing fluid according to a preset evaluation standard.
Wherein the preset evaluation criteria are as follows: recording the sand laying length X of the proppant particles in the fracture model in t time, and calculating the settling velocity v of the proppant particlespAnd a lateral migration velocity upFlow velocity u of sand-carrying fluidfAnd drag coefficient C of sand-carrying fluiddBy the length X of the sand bed, the settling velocity v of the proppant particlespAnd a lateral migration velocity upFlow velocity u of sand-carrying fluidfAnd drag coefficient C of sand-carrying fluiddAnd evaluating the performance of the fracturing fluid to be evaluated. The specific calculation principle and method are as follows:
1) settling mechanism of proppant in longitudinal direction
The fracturing fluid carries the proppant to enter the fracture and then settles in the longitudinal direction, and the proppant can be subjected to self gravity F1Liquid buoyancy F2And a liquid resistance F3The three forces act, the total force F acting on the proppant is expressed as:
F＝F1-F2-F3(1)
the gravity F borne by the proppant can be known by the universal gravitation1Comprises the following steps:
F1＝mg (2)
according to the Archimedes buoyancy principle, the buoyancy F of the liquid is applied to the proppant2Comprises the following steps:
F2＝mgρ/ρs(3)
according to the fluid resistance calculation formula, the resistance F of the proppant to the liquid is obtained3Comprises the following steps:
according to Newton's second law of motion, the resultant force F on the proppant is:
F＝ma (5)
wherein:
wherein m is the mass of the proppant particles, g is the gravitational acceleration, and ρ is the density of the sand-carrying fluid, ρsIs the density of the proppant particle, CdIs the drag coefficient of the sand-carrying fluid, A is the cross-sectional area of the proppant particle drag, vpAs the particle settling velocity, a as the acceleration of proppant particle movement, dpIs the diameter of the proppant particle.
2) Mechanism of proppant transport in the transverse direction
The particles in the horizontally flowing fluid are influenced by the fluid flow to generate horizontal transverse movement, and are acted by two forces in the horizontal direction, wherein one force is a friction force generated by the fluid driving the proppants to move horizontally, and the other force is a friction resistance between the proppants when the proppants settle to move at the bottom. The resultant force acting in the horizontal direction of the proppant is:
F＝F1-F2(8)
from the fluid resistance calculation formula, the friction force of the fluid to the proppant in the horizontal direction is:
F1＝CdAρ(uf-up)2/2 (9)
according to the sliding friction force calculation formula, the friction force applied to the proppant is as follows:
F2＝μFn(10)
Fn＝mg (11)
from newton's second law of motion, the resultant force is:
F＝ma (12)
wherein:
wherein m is the mass of the proppant particles, g is the gravitational acceleration, and ρ is the density of the sand-carrying fluid, ρsIs the density of the proppant particle, CdIs the drag coefficient of the sand-carrying fluid, A is the cross-sectional area of the proppant particle drag, vpAs the particle settling velocity, a as the acceleration of proppant particle movement, dpIs the diameter of the proppant particle.
3) Settling velocity of proppant particles in fractures
When the proppant is subjected to gravity F1Buoyancy F2And resistance F3After dynamic balance is achieved:
a＝0 (15)
the settling velocity of single proppant particles in the fracture is obtained by replacing the formulas (2), (3), (4), (5), (6), (7) and (8) with the formula (1):
the diameter d of the proppant particles is calculated through experimentspThe density rho of the sand-carrying fluid and the density rho s of the particles to obtain the settling velocity v of the single proppant in the fracturep。
4) Migration of proppant particles in the transverse direction
As the proppant velocity increases, the fluid has less and less friction against the proppant until its friction reaches an equilibrium with the dynamic friction experienced by the proppant, namely:
a＝0 (17)
the movement speed of the single proppant particles in the horizontal direction of the fracture is obtained by replacing the formulas (9), (10), (11), (12), (13), (14) and (15) with the formula (8):
calculating the sand laying length X of the proppant particles in the fracture model within t time through experiments to obtain the proppant particlesSpeed of movement u in horizontal directionp：
up＝X/t (19)
The following is obtained by substituting formula (18) for formula (19):
the diameter d of the proppant particles is calculated through experimentspDensity rho of sand-carrying liquid and density rho of particlessAnd the sand laying length X of the proppant particles in the fracture model within the time t is obtained to obtain the flow velocity u of the sand carrying liquid in the horizontal directionfCoefficient of resistance CdThe relational equation (20).
From Stokes' equation, coefficient of resistance CdAnd Reynolds number ReThe following relationships exist:
Cd＝8f(Re)/π (21)
Re＝ρufd/μa(22)
in the above formula: v. ofpIs the particle settling velocity ufIs the flow velocity of the sand-carrying fluid in the horizontal direction upIs the movement velocity of the proppant in the horizontal direction, g is the acceleration of gravity, ρs-particle density, p is sand-carrying fluid density, doIs the proppant particle diameter, CdIs the drag coefficient, μ is the kinetic friction factor, M is the particle mass, A is the cross-sectional area of particle drag, a is the proppant acceleration, μaD is the equivalent diameter for the viscosity coefficient of the sand-carrying fluid.
The density rho and the viscosity coefficient mu of the sand-carrying fluid under the conditions of different temperatures and pressuresaIn contrast, Reynolds number ReDifferent, resulting in a coefficient of resistance C under different temperature and pressure conditionsdDifferent. A plurality of groups of experiments are set under the conditions of different construction parameters such as temperature, pressure and the like, and the flow speed u of the sand-carrying liquid in the horizontal direction is obtained through a formula (20)fCoefficient of resistance Cd。
The settlement velocity v of the proppant particles is obtained by calculationpAnd a lateral migration velocity uoFlow velocity u of sand-carrying fluidfAnd drag coefficient C of sand-carrying fluiddBy the length X of the sand bed, the settling velocity v of the proppant particlespAnd a lateral migration velocity upFlow velocity u of sand-carrying fluidfAnd drag coefficient C of sand-carrying fluiddAnd evaluating the performance of the fracturing fluid to be evaluated under different conditions.
In conclusion, the actual reservoir fractures are simulated through the fracture model combination, and the mixture of the carbon dioxide gas, the propping agent and the fracturing fluid is injected into the fracture model combination through the injection mechanism 2, so that the sand carrying and laying characteristics and the change rule of the fracturing fluid are researched, and the fracturing performance of the propping agent is evaluated.
The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. The utility model provides a carbon dioxide fracturing fluid is taken sand, is spread visual analogue means of sand which characterized in that includes: a simulation mechanism and an injection mechanism, wherein,
the simulation mechanism comprises a crack model combination, the crack model combination comprises a plurality of crack models and connecting pipes, each crack model is provided with a crack cavity, and the crack cavities are communicated through the connecting pipes to form a crack network cavity;
the injection mechanism includes injection pipe, gas injection device, notes sand device and notes fracturing fluid device, the injection pipe with the one end intercommunication of fracture net cavity, the gas injection device with the injection union coupling and be used for to let in carbon dioxide gas in the injection pipe, annotate the sand device with the injection union coupling and be used for to inject into the proppant in the injection pipe, annotate the fracturing fluid device with the injection union coupling and be used for to inject into fracturing fluid in the injection pipe.
2. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device as claimed in claim 1, wherein the gas injection device comprises a carbon dioxide gas tank, a gas storage tank and a gas injection pump,
the carbon dioxide gas tank is provided with a closed first gas storage cavity;
the gas storage tank is provided with a closed second gas storage cavity which is communicated with the first gas storage cavity;
the inlet of the gas injection pump is communicated with the second gas storage cavity, and the outlet of the gas injection pump is communicated with the injection pipe.
3. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device of claim 2, wherein the gas injection device further comprises a refrigeration unit, and the refrigeration unit is arranged in the second gas storage cavity.
4. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device as claimed in claim 1, wherein the sand injection device comprises a sand storage tank and a propeller,
the sand storage tank is provided with a closed sand storage cavity;
the inlet of the propeller is communicated with the sand storage cavity, and the outlet of the propeller is communicated with the injection pipe.
5. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device as claimed in claim 1, wherein the fracturing fluid injection device comprises a fracturing fluid storage tank and a fracturing fluid propulsion device,
the fracturing fluid storage tank is provided with a closed fracturing fluid storage cavity, and the fracturing fluid storage cavity is communicated with the injection pipe;
the fracturing fluid propelling device is connected with the fracturing fluid storage tank and is used for propelling the fracturing fluid in the fracturing fluid storage cavity into the injection pipe.
6. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device as claimed in claim 5, wherein the fracturing fluid propulsion device comprises a water tank, an electronic balance and a fracturing fluid injection pump,
the water tank is provided with a closed water storage cavity and is arranged on the electronic balance;
the inlet of the fracturing fluid injection pump is communicated with the water storage cavity, and the outlet of the fracturing fluid injection pump is communicated with the fracturing fluid storage cavity.
7. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device of claim 1, further comprising a temperature control mechanism, wherein the temperature control mechanism comprises a heater and a temperature sensor, and the heater and the temperature sensor are both arranged in the injection pipe.
8. The carbon dioxide fracturing fluid sand-carrying and sand-laying visual simulation device as claimed in claim 1, further comprising a separation and recovery mechanism, wherein the separation and recovery mechanism comprises a discharge pipe, a solid separation component and a gas-liquid separation component,
one end of the discharge pipe is communicated with the other end of the crack net cavity;
the solid separation assembly comprises a solid separation tank and a liquid outlet pipe, the solid separation tank is provided with a closed solid precipitation cavity, the solid precipitation cavity is communicated with the other end of the discharge pipe, and the liquid outlet pipe is communicated with the solid precipitation cavity;
the gas-liquid separation assembly comprises a gas-liquid separation tank and a gas outlet pipe, the gas-liquid separation tank is provided with a closed gas-liquid separation cavity, and the gas outlet pipe is communicated with the gas-liquid separation cavity.
9. The visual simulation device for sand carrying and spreading of carbon dioxide fracturing fluid of claim 8, wherein the separation and recovery mechanism further comprises a pressure stabilizing assembly, the pressure stabilizing assembly comprises a back pressure valve and a nitrogen tank,
the inlet of the back pressure valve is communicated with the liquid outlet pipe, and the outlet of the back pressure valve is communicated with the gas-liquid separation cavity;
and the outlet of the nitrogen tank is communicated with the pressure input end of the backpressure valve.
10. A visual evaluation method for sand carrying and sand laying of carbon dioxide fracturing fluid is suitable for the visual simulation device for sand carrying and sand laying of carbon dioxide fracturing fluid as claimed in any one of claims 1 to 9, and comprises the following steps:
s1, obtaining the average diameter and density of the proppant to be used, and obtaining the density of the sand-carrying fluid to be used under the conditions of preset temperature and preset pressure;
s2, injecting the propping agent and the sand-carrying liquid into an injection pipe through the sand injection device;
s3, injecting carbon dioxide gas into the injection pipe through the gas injection device;
s4, injecting fracturing fluid to be evaluated into the injection pipe through the fracturing fluid injection device;
and S5, evaluating the performance of the fracturing fluid according to a preset evaluation standard.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113138140A (en) * | 2021-04-25 | 2021-07-20 | 重庆大学 | Test system and method for carbon dioxide carrying proppant |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113138140A (en) * | 2021-04-25 | 2021-07-20 | 重庆大学 | Test system and method for carbon dioxide carrying proppant |
| CN113138140B (en) * | 2021-04-25 | 2024-01-30 | 重庆大学 | Carbon dioxide carrying propping agent test system and method |
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