CN205027726U - Multi -functional fracture conductivity test system - Google Patents

Abstract

A multi-functional fracture conductivity test system, including No. 1 gas cylinder, No. 2 gas cylinder, small water container and large water container, No. 1 gas cylinder and No. 2 gas cylinder are connected with filters, and the filter and The low-temperature bath is connected, and the low-temperature bath is connected with the stirring container; the small water container is set on the No. 1 balance, and is connected with the stirring container through a pipeline; Connected with the rock sample chamber, rock samples are set in the diversion chamber, and valves, flowmeters and thermometers are set on each connecting pipeline. The utility model can select branch roads according to needs, and use conventional hydraulic fracturing fluid and pure _CO2 fracturing respectively. fluid and improved CO ₂ fracturing fluid to test fracture conductivity; this system can test complex fractures such as layered fractures, tortuous fractures, fracture network fractures, etc. under different fracturing fluids and proppant, temperature, pressure, displacement conditions of flow capacity.

Description

A Multifunctional Fracture Conductivity Testing System

technical field

The utility model belongs to the technical field of petroleum and natural gas development, in particular to a multi-functional fracture conductivity test system.

Background technique

Through fracturing technology (hydraulic fracturing, CO ₂ fracturing), oil and gas reservoirs will be transformed into complex fractures, and the conductivity of the above fractures is an important indicator for evaluating the stimulation effect of fracturing operations, and it is also important for fracturing design. optimization plays a key role. In view of the importance of fracture conductivity in the evaluation of stimulation effects in fracturing operations, a test method that can use conventional hydraulic fracturing fluid, pure CO ₂ fracturing fluid, and improved CO ₂ fracturing fluid (with chemical reagents added) was developed. Devices for the conductivity of complex fractures (layered fractures, tortuous fractures, and fracture network fractures) are particularly important. The existing fracture conductivity test system has a single function (usually only can be used for conventional hydraulic fracturing fluid related tests, or use nitrogen for experiments), and generally the measured fracture shape is simple (usually a single fracture, which cannot reflect the real situation) , and did not design the corresponding chemical reagent supply device when using _CO2 fracturing fluid testing, and at the same time ignored many important details due to excessive simplification (such as not considering the fracturing fluid and the corrosion of the pump by adding chemical reagents), This brings great inconvenience to the development of fracture conductivity test research.

Contents of the invention

In order to overcome the single function of the above-mentioned prior art, the general shape of the measured fracture is simple, no corresponding chemical reagent supply device is designed when using _CO2 fracturing fluid test, and many important details are ignored due to excessive simplification (such as Without taking into account the shortcomings of fracturing fluid and the corrosion of the pump by adding chemical reagents), the purpose of this utility model is to provide a multifunctional fracture conductivity test system, which can use conventional hydraulic fracturing fluid and _CO2 fracturing fluid to test fracture conductivity.

In order to achieve the above object, the technical solution adopted by the utility model is:

A multi-functional fracture conductivity test system, comprising a No. 1 gas cylinder 1, a No. 2 gas cylinder 2, a small water container 13 and a large water container 25, wherein the outlet of the No. 1 gas cylinder 1 is connected with the No. 1 valve 3 The inlet of the filter 5 is connected, the outlet of the No. 2 gas cylinder 2 is connected with the inlet of the filter 5 through the No. The outlet is connected to the air inlet of the stirring container 19 and the connecting pipeline is provided with a No. 1 temperature sensor 8, a No. 1 pump 9, a No. 1 safety valve 10 and a No. 1 check valve 11; the small water container 13 is arranged on the No. 1 balance 12, the small water container 13 is connected to the water inlet of the stirring container 19 through a pipeline and the connecting pipeline is provided with the third valve 14, the second pump 15, the small piston container 16, the second safety valve 17 and the second one-way valve 18. The sampling port in the middle of the stirring container 19 is connected to the diversion chamber 36 through a pipeline, and the connecting pipeline is provided with a No. 1 heater 20, a No. 2 temperature sensor 21, a No. 1 pressure gauge 22 and a No. 4 valve 23; a large water container 25 is arranged on the No. 2 balance 24, and the large-scale water container 25 is connected with the rock sample chamber 36 through pipelines, and No. 5 valve 26, No. 3 pump 27, large-scale piston container 28, No. 3 safety valve 29, No. 3 one-way valve 30 , No. 2 heater 31 , No. 3 temperature sensor 32 , No. 2 pressure gauge 33 and No. 6 valve 34 , and a rock sample 37 is arranged in the diversion chamber 36 . The pipeline behind the No. 4 valve 23 is connected in parallel with the pipeline behind the No. 6 valve 34 and then connected to the diversion chamber 36, and No. 4 temperature sensor 35 is arranged on the connecting pipeline.

The utility model is designed with a plurality of gas cylinders, which can flexibly select the access quantity of the gas cylinders, that is, the No. 1 gas cylinder 1 and the No. ₂ gas cylinder 2 according to the needs. Good save and liquify output.

Described flowmeter 6, No. 1 temperature sensor 8, No. 2 temperature sensor 21, No. 3 temperature sensor 32, No. 4 temperature sensor 35, No. 1 pressure gauge 22, No. 2 pressure gauge 33 are all connected data acquisition control card, for Real-time monitoring of the flow, temperature and pressure in the pipeline, and effective data collection.

The No. 1 safety valve 10, the No. 2 safety valve 17, and the No. 3 safety valve 29 are used to protect pipelines and instruments, and prevent excessive pump pressure from damaging pipelines or instruments.

The functions of the No. 1 check valve 11 , No. 2 check valve 18 and No. 3 check valve 30 are to prevent the backflow of CO ₂ , chemical reagents, hydraulic fracturing fluid and the like.

The filter 5 is a gas filter, and its purpose is to remove impurities mixed in the original CO ₂ and purify to obtain high-precision CO ₂ .

The No. 1 balance 12 and the No. 2 balance 24 are precision digital balances, and their purpose is to measure the displacement of the water container, and obtain the volume of the output fracturing fluid through conversion.

Both the small piston container 16 and the large piston container 28 are composed of a water tank 40, a piston 41, and a fracturing fluid tank 39, wherein the water tank 40 is at the bottom, the fracturing fluid tank 39 is at the top, and the piston 41 is located at the water tank 40 and the fracturing fluid tank Between 39. Its purpose is to prevent the direct delivery of chemical reagents and hydraulic fracturing fluid from causing damage to the pump, and use clean water to push chemical reagents and hydraulic fracturing for delivery.

The stirring container 19 is an airtight heat preservation stirring container, and its function is to make CO ₂ and chemical reagents can be effectively mixed, so that the dissolution is more sufficient.

The No. 1 heater 20 and the No. 2 heater 31 are precision digitally controlled surface heaters, and their function is to heat the fracturing fluid so as to test the conductivity of fractures under different temperature conditions.

The rock sample 37 is in close contact with its inner wall in the diversion chamber 36 . Rock sample 37 is processed from natural rocks taken from strata or outcrops in the same stratum. During processing, it can be cut into cuboid rock slabs with semicircular ends at both ends matching the size of the diversion chamber (in order to meet API guide The shape of both ends of the flow chamber is circular), and then according to the complex fracture shape (layered cracks, tortuous cracks, fracture network cracks) designed according to the needs, the above-mentioned semicircular middle cuboid rock slabs are cut horizontally and vertically, Cut into semicircular cuboid rock slabs, cuboid rock slabs, trapezoidal rock slabs, etc. at both ends that need to design crack shapes, and then design complex cracks of different shapes by laying proppant. Compared with single cracks, it can better reflect The true situation.

The diversion chamber 36 is a diversion chamber designed according to the API standard. The diversion chamber is forged with high-slip stainless steel material to prevent plastic deformation, and contains an electric heating rod inside to test the conductivity of cracks at different temperatures. At the same time, pressure sensors, differential pressure sensors, temperature sensors, displacement sensors, etc. are installed on the diversion chamber to facilitate real-time data collection, and the upper or lower cover of the diversion chamber is equipped with hydraulic jacks to simulate different pressures Effect on fracture conductivity.

All connecting pipelines of the utility model adopt 316L pipelines to prevent the acid corrosion of the pipelines by the fracturing fluid; and the pipelines connecting the low temperature bath tank 7 to the No. 4 temperature sensor 35 are wrapped with thermal insulation materials.

The utility model simultaneously provides a test method based on the multifunctional crack conductivity test system described in claim 1, comprising the following steps:

Step 1, setting the rock sample 37 in the diversion chamber 36, laying proppant to form complex cracks, and applying pressure to the upper and lower cover plates of the diversion chamber 36;

Step 2, test through the following process:

Make No. 1 valve 3, No. 2 valve 4, No. 1 pump 9, No. 3 valve 14, No. 2 pump 15, and No. 4 valve 23 open, and the CO in No. 1 gas cylinder 1 and No. 2 gas cylinder ₂ respectively Enter the filter 5 through the No. 1 valve 3 and the No. 2 valve 4, and then flow through the flow meter 6, the low temperature bath 7, the No. 1 temperature sensor 8, the No. 1 pump 9, the No. 1 safety valve 10 and the No. 1 pump after being filtered by the filter 5 One-way valve 11; No. 1 balance 12 measures the quality of water in the small-sized water container 13 simultaneously, and the water in the small-sized water container 13 flows through No. 3 valve 14, No. 2 pump 15 and then enters the bottom of small-sized piston container 16 by pipeline , the chemical reagent on the upper part of the container flows through the No. 2 safety valve 17 and the No. 2 one-way valve 18 through the piston movement in the small-sized piston container 16, and then in the stirring container 19 and flows through the No. ₁ check valve 11. Mixing, after mixing and stirring evenly, enter the No. 1 heater 20 for heat treatment, and then flow through the pipeline through No. 2 temperature sensor 21, No. 1 pressure gauge 22, No. 4 valve 23, and No. 4 temperature sensor 35 to enter the diversion chamber 36. Test the conductivity of the cracks in the rock sample 37 in the diversion chamber 36; in the process, read the temperature in the No. 1 temperature sensor 8, the No. 2 temperature sensor 21, the No. 4 temperature sensor 35, and the No. 1 pressure gauge 22 in real time. Monitoring data; real-time collection of data from the pressure sensor, differential pressure sensor, temperature sensor, and displacement sensor installed in the diversion chamber 36, and calculation of the equivalent fracture width and permeability, and then the fracture conductivity, so as to realize CO ₂ fracturing The test of the flow conductivity of the liquid branch to the fracture;

Or, make No. 5 valve 26, No. 3 pump 27, and No. 6 valve 34 in open state, measure the quality of water in the large-scale water container 25 with No. 2 balance 24 simultaneously, the water in the large-scale water container 25 flows through pipeline No. 5 valve 26 and No. 3 pump 27 then enter the lower part of the large piston container 28, and the hydraulic fracturing fluid in the upper part of the container flows through the No. 3 safety valve 29 and No. 3 one-way valve 30 through the movement of the piston in the large piston container 28. , then enter No. two heater 31 for heat treatment, and then flow through No. three temperature sensor 32, No. two pressure gauge 33, No. six valve 34, and No. four temperature sensor 35 through the pipeline to enter the diversion chamber 36, in the diversion Test the flow conductivity of the cracks in the rock sample 37 in the chamber 36; in the process, read the monitoring data in No. 3 temperature sensor 32, No. 2 pressure gauge 33, and No. 4 temperature sensor 35 in real time; Based on the data of the pressure sensor, differential pressure sensor, temperature sensor, and displacement sensor, the equivalent fracture width and permeability are calculated, and then the fracture conductivity is obtained, so as to realize the test of the fracture conductivity of the conventional hydraulic fracturing fluid branch.

The complex fractures in Step 1 include layered fractures, tortuous fractures and fracture network fractures,

When the fracture form is a layered fracture, its formation process is as follows:

Take the natural rock outcropped in the stratum or the same stratum, and first cut it into cuboid slabs with semicircular ends and middle cuboids matching the size of the diversion chamber 36;

According to the required number of layers, horizontally cut the cuboid rock slabs with semicircular middle ends into several thin rock slabs with semicircular middle cuboids at both ends. The proppant is sequentially laid between the upper cover plate and the lower cover plate in the diversion chamber 36, and the part in contact with the diversion chamber 36 is sealed with silica gel;

When the fracture form is a zigzag fracture, the formation process is as follows:

Take the natural rock outcropped in the stratum or the same stratum, and first cut it into cuboid slabs with semicircular ends and middle cuboids matching the size of the diversion chamber 36;

According to the required angle, rock bridge length and crack length, the cuboid rock slabs in the middle of the semicircle at both ends are cut into multiple cuboid rock slabs with one end semicircle, cuboid rock slabs and trapezoidal rock slabs. The rock slab and proppant are sequentially laid between the upper cover plate and the lower cover plate in the diversion chamber 36, wherein the part in contact with the diversion chamber 36 is sealed with silica gel;

When the fracture form is a fracture network, the formation process is as follows:

Take the natural rock outcropped in the stratum or the same stratum, and first cut it into cuboid slabs with semicircular ends and middle cuboids matching the size of the diversion chamber 36;

According to the required length and quantity of cracks, cut the cuboid slabs with semicircular ends at both ends into multiple cuboid slabs with semicircular ends at one end and cuboid slabs. Between the upper cover plate and the lower cover plate in the chamber 36, the part in contact with the diversion chamber 36 is sealed with silica gel.

Compared with the prior art, the utility model can select branches according to needs to test the fracture conductivity by using conventional hydraulic fracturing fluid, pure CO ₂ fracturing fluid, and improved CO ₂ fracturing fluid (added with chemical reagents).

Description of drawings

Fig. 1 is a schematic diagram of the rock sample layered crack morphology of the utility model.

Fig. 2 is a schematic diagram of the rock sample tortuous fracture shape of the utility model.

Fig. 3 is a schematic diagram of the crack morphology of the rock sample fracture network of the utility model.

Fig. 4 is a structural schematic diagram of the utility model.

Fig. 5 is a specific structural schematic view of the small and medium-sized piston container and the large piston container of the utility model, which have the same structure but different sizes.

detailed description

The implementation of the utility model will be described in detail below in conjunction with the accompanying drawings and examples.

As shown in Fig. 1, Fig. 2 and Fig. 3, the complex fracture patterns of rock samples designed by the utility model include layered fractures, tortuous fractures and fracture network fracture patterns.

As shown in Figure 4, a multi-functional fracture conductivity testing system of the present invention includes a No. 1 gas cylinder 1, a No. 2 gas cylinder 2, a No. 1 valve 3, a No. 2 valve 4, a filter 5, and a flow meter 6 , low temperature bath 7, No. 1 temperature sensor 8, No. 1 pump 9, No. 1 safety valve 10, No. 1 one-way valve 11, No. 1 balance 12, small water container 13, No. 3 valve 14, No. 2 pump 15, Small piston container 16, No. 2 safety valve 17, No. 2 one-way valve 18, stirring container 19, No. 1 heater 20, No. 2 temperature sensor 21, No. 1 pressure gauge 22, No. 4 valve 23, No. 2 balance 24, Large water container 25, No. 5 valve 26, No. 3 pump 27, large piston container 28, No. 3 safety valve 29, No. 3 check valve 30, No. 2 heater 31, No. 3 temperature sensor 32, and No. 2 pressure gauge 33. No. 6 valve 34, No. 4 temperature sensor 35, diversion chamber 36 and rock sample 37.

No. 1 gas cylinder 1 and No. 2 gas cylinder 2 are respectively connected to the inlet of filter 5 through No. 1 valve 3 and No. 2 valve 4; the outlet of filter 5 is connected to flow meter 6, low temperature bath 7 and No. The sensor 8, the No. 1 pump 9, the No. 1 safety valve 10, and the No. 1 one-way valve 11 are connected; the No. 1 balance 12 is in contact with the small water container 13 through a plane; the small water container 13 is connected to the No. 14. The No. 2 pump 15, the small piston container 16, the No. 2 safety valve 17, and the No. 2 check valve 18 are connected; The heaters 20 are connected; the No. 1 heater 20 is connected with the No. 2 temperature sensor 21, the No. 1 pressure gauge 22, and the No. 4 valve 23 through pipelines; the No. 2 balance 24 is in contact with the large water container 25 through a plane; The water container 25 is connected with No. 5 valve 26, No. 3 pump 27, large piston container 28, No. 3 safety valve 29, No. 3 check valve 30, No. 2 heater 31, No. 3 temperature sensor 32, and No. 2 through pipeline successively. Pressure gauge 33 and No. 6 valve 34 are connected; the branch represented by No. 4 valve 23 or the branch represented by No. 6 valve 34 is connected with No. 4 temperature sensor 35 through the pipeline; No. 4 temperature sensor 35 is connected with the guide through the pipeline. The flow chamber 36 is connected; the rock sample 37 is placed in the flow chamber 36, and the two are in close contact.

As shown in Figure 5, both the small piston container 16 and the large piston container 28 are composed of a water tank 40, a piston 41, and a fracturing fluid tank 39, wherein the water tank 40 is below, the fracturing fluid tank 39 is above, and the piston 41 is located between the water tank 40 and the fracturing fluid tank 39. Between the fracturing fluid tanks 39. The small piston container 16 and the large piston container 28 are used to push the chemical reagents and hydraulic fracturing in the fracturing fluid tank 39 to be transported in order to prevent the pump from being directly transported by chemical reagents and hydraulic fracturing fluid.

The natural rock outcropped in the stratum or the same stratum is processed into rock sample 37. During processing, it can be cut into cuboid rock slabs with semicircles at both ends matching the size of the diversion chamber (in order to meet the API diversion chamber at both ends). The shape is circular), and then according to the complex fracture shapes (layered cracks, tortuous cracks, and crack network cracks) as shown in Figure 1-3, the cuboid rock slabs in the middle of the semicircle at both ends are processed. Horizontal and longitudinal cutting, cutting into semicircular middle cuboid rock slabs, cuboid rock slabs, trapezoidal rock slabs, etc. that need to design crack shapes, and then design complex cracks of different shapes by laying proppant.

In the specific operation process of forming complex fractures, (1) when the fracture form is a layered fracture, the natural rock can be processed into a cuboid rock slab with semicircular ends at both ends, and then the number of layers designed according to the needs (such as 2 layer or 3 layers, the schematic diagram is 2 layers, but it can be designed as multi-layer according to the needs) cut the cuboid rock slab with semicircle at both ends into a plurality of cuboid thin rock slabs with semicircle at both ends, after cutting, cut the two Thin rock slabs with semicircular ends and cuboid in the middle and proppant are laid sequentially between the upper cover plate and the lower cover plate in the diversion chamber, and the contact part between the rock slab and the diversion chamber is sealed with silica gel; (2) when the crack shape is zigzag When there are cracks, the natural rock can be processed into semicircular middle cuboid slabs at both ends first, and then the semicircular middle cuboid slabs at both ends can be cut into multiple one ends according to the desired angle, rock bridge length, crack length, etc. Semicircular cuboid rock slabs, rectangular parallelepiped rock slabs, trapezoidal rock slabs, etc., after cutting, lay the above rock slabs and proppant between the upper cover and the lower cover in the diversion chamber in sequence, and the rock slabs and the diversion The contact part of the chamber is sealed with silica gel; (3) When the crack form is a fracture network crack, the natural rock can be processed into a semicircular cuboid slab in the middle at both ends, and then the length and quantity of the cracks at both ends are designed according to the needs. The semicircular middle cuboid rock slab is cut into multiple one-end semicircular cuboid rock slabs, cuboid rock slabs, etc. After the cutting is completed, the above rock slabs and proppant are laid sequentially between the upper cover plate and the lower cover plate in the diversion chamber. Between, and the contact part between the rock plate and the diversion chamber is sealed with silica gel. After laying and forming complex cracks, hydraulic jacks are used to exert pressure on the upper and lower cover plates of the diversion chamber.

After laying and forming complex fractures and applying pressure to the fractures, the diversion chamber 36 is connected to the CO ₂ fracturing fluid branch or the conventional hydraulic fracturing fluid branch to evaluate the diversion of the fracture to different fracturing fluids and proppants ability.

When the _CO2 fracturing fluid branch works to test the fracture conductivity, the No. 1 valve 3, the No. 2 valve 4, the No. 1 pump 9, the No. 3 valve 14, the No. 2 pump 15, and the No. The CO2 in the No. 1 gas cylinder and the No. 2 gas cylinder ₂ enters the filter 5 through the No. 1 valve 3 and No. 2 valve 4 respectively, and after being filtered by the filter 5, it flows through the flow meter 6, the low temperature bath 7, and the No. 1 temperature sensor in sequence 8. No. 1 pump 9, No. 1 safety valve 10, and No. 1 one-way valve 11; at the same time, No. 1 balance 12 is used to measure the quality of water in the small water container 13, and the water in the small water container 13 flows through the pipeline. No. three valve 14, No. two pump 15 then enter the bottom of small piston container 16, and the chemical reagent on the top of the container flows through No. two safety valve 17, No. two one-way valve 18 by the piston movement in small piston container 16, and then In the stirring container 19, it is mixed with the _CO2 flowing through the No. 1 check valve 11. After being mixed and stirred evenly, it enters the No. 1 heater 20 for heat treatment, and then flows through the No. 2 temperature sensor 21 and the No. 1 pressure gauge in turn through the pipeline. 22, No. 4 valve 23, No. 4 temperature sensor 35 and enter diversion chamber 36, in diversion chamber 36, test the flow-conducting ability of crack in rock sample 37; No. temperature sensor 21, No. 4 temperature sensor 35, and No. 1 pressure gauge 22 monitoring data; real-time collection of data on the pressure sensor, differential pressure sensor, temperature sensor, displacement sensor, etc. installed on the diversion chamber 36, so as to facilitate subsequent calculations Conductivity, when specifically calculating the conductivity, the equivalent fracture width is obtained through proper calculation from the height of the original diversion chamber, slab size, proppant volume, and data obtained from the displacement sensor; when calculating the permeability , because the density and viscosity of supercritical CO ₂ are sensitive to temperature and pressure, and the temperature and pressure change with time during the experiment, so Darcy's law and the permeability formula of the ideal gas state equation are no longer applicable to supercritical CO ₂ permeation For this reason, the fracture permeability is obtained by the permeability formula given by Liang Weiguo et al. through the standard conversion of parameters such as flow rate and area. The principle of the permeability calculation formula is detailed in the literature (Liang Weiguo, Zhang Beining, Han Junjie , et al. Supercritical CO ₂ flooding coal seam CH4 device and experimental research [J]. Coal Journal, 2014, 39(8): 1511-1520); finally, the fracture width can be calculated by multiplying the equivalent fracture width and permeability diversion capacity.

The specific calculation formula is as follows:

(kw) _f =k _f ×w _f (1)

${\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 9.81</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 11</span>}}\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; L\&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}}}{{\mathrm{<span\; class="notranslate">\; A\&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula: (kw) _f —fracture conductivity; k _f —fracture permeability; w _f —effective fracture width; Q _m —mass flow rate; _L —rock sample length; Viscosity of supercritical CO ₂ under P condition; A—cross-sectional area of rock sample; ρ _T,P —density of supercritical CO ₂ under experimental temperature T and pressure P; P ₁ —inlet pressure; P ₂ — Outlet pressure; V—the total volume of the actual fracture; S—the cross-sectional area of the diversion chamber.

When the conventional hydraulic fracturing fluid branch works to test the fracture conductivity, the No. 5 valve 26, the No. 3 pump 27, and the No. 6 valve 34 are in the open state, and the No. 2 balance 24 is used to measure the volume of water in the large water container 25. Quality, the water in the large water container 25 flows through the pipeline through No. 5 valve 26 and No. 3 pump 27 and then enters the bottom of the large piston container 28, and the hydraulic fracturing fluid in the upper part of the container is moved by the piston movement in the large piston container 28. Flow through No. 3 safety valve 29, No. 3 one-way valve 30, then enter No. 2 heater 31 for heat treatment, and then flow through No. 3 temperature sensor 32, No. 2 pressure gauge 33, No. 6 valve 34, No. 4 No. temperature sensor 35 enters the diversion chamber 36, and tests the flow conductivity of the cracks in the rock sample 37 in the diversion chamber 36; Monitoring data in the sensor 35; real-time collection of data on the pressure sensor, differential pressure sensor, temperature sensor, displacement sensor, etc. The fracture width is calculated from the height of the original diversion chamber, the size of the slab, the volume of the proppant, and the data obtained from the displacement sensor, etc.; the fracture permeability is calculated from Darcy's law through standard conversion of parameters such as flow rate and area. Finally, the fracture conductivity can be obtained by multiplying the equivalent fracture width by the permeability.

Claims (8)

1. A multifunctional fracture conductivity testing system, characterized in that, Including No. 1 gas cylinder (1), No. 2 gas cylinder (2), small water container (13) and large water container (25), wherein the outlet of No. 1 gas cylinder (1) passes through No. 1 valve (3) Connect with the inlet of the filter (5), the outlet of the No. 2 cylinder (2) is connected with the inlet of the filter (5) through the No. 2 valve (4), and the filter (5) is connected with the inlet of the cryogenic bath (7) And there is a flow meter (6) on the connecting pipeline, the outlet of the cryogenic bath (7) is connected with the air inlet of the stirring vessel (19) and a No. temperature sensor (8), No. 1 pump (9), No. 1 safety valve (10) and No. 1 one-way valve (11); Small-sized water container (13) is arranged on No. 1 balance (12), and small-sized water container (13) passes through pipeline and stirring container (19) The water inlet is connected and the connecting pipeline is provided with No. 3 valve (14), No. 2 pump (15), small piston container (16), No. 2 safety valve (17) and No. 2 one-way valve (18); the stirring container ( 19) The sampling port in the middle is connected to the diversion chamber (36) through a pipe, and the No. 1 heater (20), No. 2 temperature sensor (21), No. 1 pressure gauge (22) and No. 4 valve ( 23); the large water container (25) is arranged on the No. 2 balance (24), and the large water container (25) is connected with the rock sample chamber (36) through a pipeline and the connecting pipeline is provided with a valve No. 5 (26) in sequence , No. 3 pump (27), large piston container (28), No. 3 safety valve (29), No. 3 check valve (30), No. 2 heater (31), No. 3 temperature sensor (32), No. 2 Pressure gauge (33) and No. 6 valve (34), rock sample (37) is arranged in described diversion chamber (36). 2. according to the described multifunctional fracture conductivity test system of claim 1, it is characterized in that, the pipeline behind No. 4 valve (23) and the pipeline behind No. 6 valve (34) are connected in parallel with diversion chamber (36) , and No. 4 temperature sensor (35) is set on the connecting pipeline. 3. according to the described multifunctional fracture conductivity test system of claim 2, it is characterized in that, described flowmeter (6), No. one temperature sensor (8), No. two temperature sensor (21), No. three temperature sensor ( 32), No. 4 temperature sensor (35), No. 1 pressure gauge (22) and No. 2 pressure gauge (33) are all connected to the data acquisition control card for real-time monitoring of the flow, temperature and pressure in the pipeline, and effectively Data collection. 4. The multifunctional fracture conductivity testing system according to claim 1, characterized in that the filter (5) is a gas filter. 5. according to the described multifunctional fracture conductivity testing system of claim 1, it is characterized in that, described small-sized piston container (16) and large-scale piston container (28) all are made of water tank (40), piston (41), fracturing The liquid tank (39) is formed, wherein the water tank (40) is below, the fracturing liquid tank (39) is above, and the piston (41) is located between the water tank (40) and the fracturing liquid tank (39). 6. The multifunctional fracture conductivity testing system according to claim 1, characterized in that the rock sample (37) is in close contact with its inner wall in the diversion chamber (36). 7. according to the described multifunctional fracture conductivity test system of claim 1, it is characterized in that, all connecting pipelines all adopt 316L pipeline, in order to prevent the acid corrosion of pipeline by fracturing fluid; And connect cryogenic bath (7) to No. 4 The pipelines of temperature sensor (35) are all wound and wrapped with thermal insulation material. 8. The multifunctional fracture conductivity testing system according to claim 1, characterized in that, the inside of the diversion chamber (36) is provided with an electric heating rod, and a pressure sensor, a differential pressure sensor, a temperature sensor and a displacement sensor are installed. sensor, and the upper or lower cover of the diversion chamber (36) is equipped with a hydraulic jack.