CN106644820A - Shale gas desorption capacity tester under action of slickwater - Google Patents

Abstract

The invention relates to a structure for testing the desorption capacity of shale gas under the action of slick water indoors in the petroleum industry, in particular to a tester for the desorption capacity of shale gas under the action of slick water, which includes gas source supply connected in series on the pipeline system, a gas pressurized storage system, and a constant temperature measurement system located in a constant temperature box, the constant temperature box is controlled by a control cabinet with a PLC control panel; the pipeline between the gas pressurized storage system and the constant temperature measurement system passes through A volume metering system and a vacuum pumping system are connected to the root bypass connecting pipe. The volume metering system and the vacuum pumping system are respectively located at the front ends of the two bypass connecting pipes. The gas outlet; the gas outlet of the constant temperature measurement system communicates with the vent pipe. The advantages of the present invention due to the structure are: the experimental result can be obtained only by simple calculation, the experimental accuracy is improved and the experimental cycle is shortened.

Description

Shale gas desorption capacity tester under the action of slick water

technical field

The invention relates to a test structure for the desorption capacity of shale gas under the action of slick water indoors in the petroleum industry, in particular to a test structure for the desorption capacity of shale gas under the action of slick water through simple calculation to obtain the experimental results, improve the accuracy of the experiment and shorten the experimental period tester.

Background technique

Slippery water is a fracturing body fluid composed of clear water and various additives [additives are drag reducers, synergists, anti-swelling agents, defoamers, etc.]; water accounts for 99% of the total volume, and additives It directly determines the performance of fracturing fluid.

Slippery water fracturing fluid is currently the most widely used fracturing fluid technology in shale gas development operations in the United States. It not only reduces fracturing costs by 65% compared with large-scale hydraulic fracturing, but also increases the ultimate recovery rate of shale gas by 20%. Slippery water fracturing is mainly suitable for strata with low water sensitivity, well-developed natural fractures and high brittleness. Compared with conventional jelly fracturing, it has low friction and can be pumped in a large amount under high displacement to form a deeper and more complex fracture network, obtain larger volume of stimulated reservoir, and better fracturing effect; less residue , less damage to the reservoir; easy to flow back, easy to recycle, less environmental pollution; low cost.

However, there are still some deficiencies that need to be solved urgently, such as: poor sand-carrying capacity due to low viscosity; narrow fracture network width formed during fracturing; high pump injection displacement required; low efficiency and large consumption, etc. . In practical application, the formula of slick water fracturing fluid should be determined according to the reservoir characteristics and experiments of fracturing construction. When selecting fracturing fluid additives, factors such as pump speed and pressure, clay content, potential for siliceous and organic debris formation, microbial activity, and fracturing fluid flowback should be considered.

The technical problems of the experimental testing equipment in the prior art are: the test period is long, and the required experimental data must be obtained through complex calculations using the Boyle-Mariotte law, resulting in large errors and low precision of the obtained experimental data.

Contents of the invention

The object of the present invention is to provide a shale gas desorption capacity tester under the action of slick water, which obtains the experimental results through simple calculation, improves the experimental accuracy and shortens the experimental period.

The technical solution adopted to achieve the above purpose is as follows, that is, a shale gas desorption capacity tester under the action of slick water, which includes: a gas source supply system connected in series on the pipeline, a gas pressurized storage system, A constant temperature measurement system located in a constant temperature box, which is controlled and operated by a control cabinet with a PLC control panel;

The pipeline between the gas pressurized storage system and the constant temperature measurement system is connected with a volume metering system and a vacuum system through two bypass connecting pipes, and the volume metering system and the vacuum system are respectively located in the two bypass connecting pipes The front end of the two bypass connecting pipes is located at the outlet end of the gas pressurized storage system;

The outlet end of the constant temperature measurement system is communicated with the vent pipe;

The gas source supply system further includes at least one gas source supply line, and the gas source supply line also includes gas cylinders and check valves sequentially connected in series on the gas source supply pipeline, and the gas outlet end of the gas source supply pipeline is connected to the gas booster. The intake port of the pressure storage system is connected;

The gas pressurization storage system further includes a gas booster pump and at least one gas booster line, and the gas booster line also includes a buffer tank, a pressure regulating valve, and a one-way valve sequentially connected in series on the gas booster line; The inlet end of the gas booster pipeline communicates with the gas booster pump, and the gas outlet end of the gas booster line communicates with the inlet end of the constant temperature measurement system and the ends of the two bypass connecting pipes; the gas booster pump The air inlet end communicates with the air outlet end of the air source supply pipeline;

The constant temperature measurement system further includes at least one constant temperature measurement line, and the constant temperature measurement line also includes a first pressure sensor, a first control valve, a second pressure sensor, and a second control valve sequentially arranged on the constant temperature measurement pipeline; A first bypass pipe is arranged on the constant temperature measurement pipeline between the pressure sensor and the first control valve, and a third control valve and a reference chamber are arranged on the first bypass pipe, which is fixed on the wall of the reference chamber for detecting reference A first temperature sensor for the temperature of the chamber cavity; a second bypass pipe is arranged on the constant temperature measurement pipeline between the second pressure sensor and the second control valve, and the second bypass pipe is sequentially provided with a fourth control valve, The rock core chamber and the fifth control valve are fixed on the outer wall of the rock core chamber and are used to detect the second temperature sensor of the inner cavity temperature of the rock core chamber, and the fifth control valve communicates with the output end of the slick water injection pipeline of the slick water injection system;

The volume metering system further includes a brine container, a graduated measuring tube and a fifth manual valve connected in series to the first of the two bypass connecting pipes, the brine container is located at the first The front end of the bypass connecting pipe;

The vacuum pumping system further includes a vacuum pump and a fourth manual valve sequentially connected in series on the second bypass connecting pipe of the two bypass connecting pipes, and the vacuum pump is located at the forefront of the second bypass connecting pipe;

The slick water injection system further includes a slick water injection pipeline, an intermediate container and an injection pump are arranged on the slick water injection pipeline, and the output end of the injection pump is connected to the piston in the inner cavity of the intermediate container;

The one-way valve in the gas source supply system, the gas booster pump, pressure regulating valve, and one-way valve in the gas pressurized storage system, the first pressure sensor and the first control valve in the constant temperature measurement system , the second pressure sensor, the second control valve, the third control valve, the first temperature sensor, the fourth control valve, the fifth control valve, the second temperature sensor, the vacuum pump in the vacuum pumping system, the slick water injection The injection pumps in the system are all controlled by the control cabinet with PLC control board;

The control cabinet with the PLC control sheet is provided with a display and an input operation panel.

In order to achieve the best comprehensive effect, further: the gas source supply system has three gas supply lines, the gas pressurization storage system has three gas pressurization lines, and the constant temperature measurement system has four constant temperature measurement lines ;

The gas outlet ends of the three gas source supply lines communicate with the gas inlet end of the gas booster pump of the gas booster storage system through the first four-way valve;

The inlet ends of the three gas boosting lines communicate with the gas outlet of the gas booster pump through the second four-way valve, and the gas outlet ends of the three gas booster lines are connected to the inlet end of the constant temperature measurement system through the six-way valve, two The end of the root bypass connecting pipe is connected;

The intake ends of the four constant temperature measurement lines are connected to the six-way valve through the first five-way valve, and the fifth control valve on the four constant temperature measurement lines is connected to the slick water injection line of the slick water injection system through the second five-way valve. The output is connected.

The advantages of the present invention due to the above structure are: the experimental result can be obtained only by simple calculation, the experimental accuracy is improved and the experimental cycle is shortened.

Description of drawings

The invention can be further illustrated by the non-limiting examples given in the accompanying drawings.

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a control block diagram of the electromagnetic valve used in the present invention.

Fig. 3 is a control block diagram of a hydraulic valve or a pneumatic valve in the present invention.

Fig. 4 is a structural schematic diagram of the core chamber of the present invention.

Fig. 5 is a structural schematic diagram of a graduated measuring tube according to the present invention.

In the figure: A, gas supply system; B, gas pressurized storage system; C, constant temperature measurement system; D, volume measurement system; E, vacuum system; F, slick water injection system; 1, vent pipe; 2 1. Gas booster pump; 3. Salt water container; 4. Measuring tube with scale; 5. Vacuum pump; 6. Intermediate container; 7. Injection pump; 8. Control cabinet with PLC control piece; 9. Display; 10. Input Operation panel; 11. Vacuum container; 1201;; 13. Gas cylinder I; 14. Gas cylinder II; 15. Gas cylinder III; 16. One-way valve I; 17. One-way valve II; 18. One-way valve III; 19. Manual valve Ⅰ; 20. Manual valve Ⅱ; 21. Manual valve Ⅲ; 22. Manual valve Ⅳ; 23. Manual valve Ⅴ; 24. Buffer tank Ⅰ; 25. Pressure regulating valve Ⅰ; 26. One-way valve Ⅴ; 27. Buffer tank Ⅱ; 28. Pressure regulating valve Ⅱ; 29. Check valve Ⅵ; 30. Buffer tank Ⅲ; 31. Pressure regulating valve Ⅲ; 32. Check valve Ⅶ; 33. Pressure sensor Ⅰ; 34. Control valve Ⅰ; 35. Pressure sensor Ⅱ; 36. Control valve Ⅱ; 37. Control valve Ⅲ; 38. Reference chamber Ⅰ; 39. Temperature sensor Ⅰ; 40. Control valve Ⅳ; 41. Rock core chamber Ⅰ; 42. Temperature sensor Ⅱ; 43. Control valve Ⅴ; 44. Pressure sensor Ⅲ; 45. Control valve Ⅵ; 46. Pressure sensor Ⅳ; 47. Control valve Ⅶ; 48. Control valve Ⅷ; 49. Reference chamber Ⅱ; 50. Temperature sensor Ⅲ; 51. Control valve IX; 52. Rock core chamber II; 53. Temperature sensor IV; 54. Control valve X; 55. Pressure sensor V; 56. Control valve XI; 57. Pressure sensor VI; 58. Control valve XII; 59. Control valve XIII; 60. Reference chamber III; 61. Temperature sensor V; 62. Control valve XIV; 63. Core chamber III; 64. Temperature sensor VI; 65. Control valve XV; 66. Pressure sensor VII; 67. Control valve XVI; 68. Pressure sensor Ⅷ; 69. Control valve XVII; 70. Control valve XVIII; 71. Reference chamber Ⅳ; 72. Temperature sensor Ⅶ; 73. Control valve XIX; 74. Rock core chamber Ⅳ; 75. Temperature sensor Ⅷ; 76. Control valve XX; 77, four-way valve I; 78, four-way valve II; 79, six-way valve; 80, five-way valve I; 81, five-way valve II.

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

Referring to accompanying drawings 1 to 5, the shale gas desorption capacity tester under the action of slick water in the figure is characterized in that it includes a gas source supply system A, a gas pressurized storage system B connected in series on the pipeline, and is located at a constant temperature The constant temperature measurement system C in the box, the said constant temperature box is controlled by the control cabinet 8 with PLC control panel to run;

The pipeline between the gas pressurized storage system B and the constant temperature measurement system C is connected with a volume metering system D and a vacuum system E through two bypass connecting pipes, and the volume meter system D and the vacuum system E are respectively located at The front ends of the two bypass connecting pipes, the ends of the two bypass connecting pipes are located at the gas outlet end of the gas pressurized storage system B;

The outlet end of the constant temperature measurement system C is communicated with the vent pipe 1;

The gas source supply system A further includes at least one gas source supply line, and the gas source supply line also includes gas cylinders and check valves sequentially connected in series on the gas source supply pipeline, and the gas outlet end of the gas source supply pipeline is connected to the gas supply line. The intake port of the pressurized storage system B is connected;

The gas pressurization storage system B further includes a gas booster pump 2 and at least one gas booster line, and the gas booster line also includes a buffer tank, a pressure regulating valve, a one-way Valve; the inlet end of the gas booster pipeline communicates with the gas booster pump 2, and the gas outlet end of the gas booster pipeline communicates with the inlet end of the constant temperature measurement system C and the ends of the two bypass connecting pipes; the gas The inlet end of the booster pump 2 communicates with the outlet end of the gas source supply pipeline;

The constant temperature measurement system C further includes at least one constant temperature measurement line, and the constant temperature measurement line also includes a first pressure sensor, a first control valve, a second pressure sensor, and a second control valve sequentially arranged on the constant temperature measurement pipeline; A first bypass pipe is arranged on the constant temperature measuring pipeline between a pressure sensor and the first control valve, and a third control valve and a reference chamber are arranged on the first bypass pipe, which is fixed on the wall of the reference chamber for detecting Reference to the first temperature sensor of the chamber temperature; a second bypass pipe is provided on the constant temperature measurement pipeline between the second pressure sensor and the second control valve, and a fourth control valve is sequentially provided on the second bypass pipe , the rock core chamber and the fifth control valve, the second temperature sensor fixed on the outer wall of the rock core chamber for detecting the temperature of the inner chamber of the rock core, the fifth control valve communicates with the output end of the slick water injection pipeline of the slick water injection system F ;

The volume metering system D further includes a saline container 3 connected in series on the first bypass connecting pipe among the two bypass connecting pipes, a graduated measuring tube 4 and a fifth manual valve, the saline container 3 Located at the front end of the first bypass connecting pipe;

The vacuum pumping system E further includes a vacuum pump 5 and a fourth manual valve sequentially connected in series on the second bypass connecting pipe of the two bypass connecting pipes, and the vacuum pump 5 is located at the end of the second bypass connecting pipe. front end;

The slick water injection system F further includes a slick water injection pipeline, an intermediate container 6 and an injection pump 7 are arranged on the slick water injection pipeline, and the output end of the injection pump 7 is connected to the piston in the inner cavity of the intermediate container 6;

The one-way valve in the gas source supply system A, the gas booster pump 2, pressure regulating valve, and one-way valve in the gas pressurized storage system B, the first pressure sensor in the constant temperature measurement system C, The first control valve, the second pressure sensor, the second control valve, the third control valve, the first temperature sensor, the fourth control valve, the fifth control valve, the second temperature sensor, the vacuum pump 5 in the vacuum pumping system E , the injection pump 7 in the slick water injection system F is controlled by a control cabinet 8 with a PLC control panel;

The control cabinet 8 with the PLC control board is provided with a display 9 and an input operation panel 10 .

In order to achieve the best comprehensive effect, in the above embodiment, preferably: the gas supply system A has three gas supply lines, the gas pressurization storage system B has three gas pressurization lines, and the constant temperature measurement There are four constant temperature measuring lines of system C;

The gas outlet ends of the three gas source supply lines communicate with the gas intake end of the gas booster pump 2 of the gas booster storage system B through the first four-way valve;

The inlet ends of the three gas boosting lines communicate with the gas outlet of the gas booster pump 2 through the second four-way valve, and the gas outlet ends of the three gas booster lines communicate with the inlet end of the constant temperature measurement system C through the six-way valve , The ends of the two bypass connecting pipes are connected;

The intake ends of the four constant temperature measurement lines are connected to the six-way valve through the first five-way valve, and the fifth control valve on the four constant temperature measurement lines is connected to the slick water injection line of the slick water injection system F through the second five-way valve The output terminal is connected.

In order to achieve the best overall effect, in the above embodiment, preferably: a manual valve is provided on the gas source supply pipeline between the gas cylinder and the one-way valve of the gas source supply system A.

In order to further shorten the experiment time, in the above-mentioned embodiment, preferably: the rock core chamber of the constant temperature measurement system C further includes a tank body 1201, a cover body 1203 that closes the inner cavity of the tank body 1201, and is fixed to the inner cavity of the tank body 1201 The core cup 1204 at the bottom, the outer diameter of the core cup 1204 matches the inner diameter of the inner cavity of the tank body 1201, the top port of the rock core cup 1204 is lower than the top port of the tank body 1201, and the top port of the rock core cup 1204 is in line with the tank body An inflatable cavity 1205 is formed between the top ports of 1201, and the inner cavity of the core cup 1204 is a shale powder filling cavity 1206; the second temperature sensor communicates with the aerating cavity 1205 or the shale powder filling cavity 1206;

The gas outlet of the second bypass pipe passing through the cover 1203 is located in the aeration cavity 1205, and the liquid outlet of the slick water injection pipeline F of the slick water injection system F passing through the bottom plate of the tank body 1201 and the core cup 1204 in turn is located in the shale The powder fills cavity 1206 .

In order to ensure a balanced flow of slick water, in the above embodiment, preferably: the pipe section of the slick water injection pipeline of the slick water injection system F located in the shale powder filling chamber 1206 is evenly distributed with liquid outlet holes 1207 .

In order to protect the safety of the vacuum pump 5 and prevent the backflow liquid from entering the vacuum pump 5, in the above embodiment, preferably: the second bypass connection pipe between the vacuum pump 5 and the fourth manual valve of the vacuum pumping system E A vacuum container 11 is provided.

In order to further realize automation, in the above embodiment, preferably: the one-way valve in the gas source supply system A, the pressure regulating valve and the one-way valve in the gas pressurized storage system B, the constant temperature measurement system C The first control valve, the second control valve, the third control valve, the fourth control valve and the fifth control valve all adopt battery valves and are opened and closed by the control cabinet 8 with PLC control board. The one-way valve in the gas source supply system A, the pressure regulating valve and one-way valve in the gas pressurized storage system B, the first control valve, the second control valve, and the first control valve in the constant temperature measurement system C The three control valves, the fourth control valve, and the fifth control valve all adopt hydraulic valves or pneumatic valves, and the hydraulic valves or pneumatic valves are opened and closed by corresponding hydraulic pumps or pneumatic pumps, and the hydraulic pumps or pneumatic pumps are controlled by a PLC The control cabinet 8 of the control panel controls the operation, and the hydraulic pump or air pump communicates with a high-pressure hydraulic source or a high-pressure air source.

The components involved in all the above-mentioned embodiments can be obtained from the market, and the slick water injection system F is an automatic injection structure sold on the market.

Below we describe the experimental process with three gas source supply lines of the gas source supply system A, three gas pressurization lines of the gas pressurized storage system B, and four constant temperature measurement lines of the constant temperature measurement system C. .

1. Volume calibration of constant temperature measurement system C

1.1 System volume calibration

[1] Calibration of the system volume V1 of the first constant temperature measurement line [The arrangement of the first constant temperature measurement line to the fourth constant temperature measurement line is from top to bottom as seen from attached drawing 1]

The system volume V1 of the first constant temperature measuring line is the sum of the volumes of all closed spaces between the six-way valve 79 and the reference chamber I38, the control valve II and the control valve V;

Test steps: Open control valve I33, control valve III37, control valve IV40, five-way valve I80, six-way valve 79, manual valve VIV22, manual valve V23, close control valve V43, control valve II36, so that the first A constant temperature measurement line forms a control channel connected with the volume metering system D and the vacuum system E; start the vacuum pump 5, vacuumize to 10Pa, and the solution in the brine container 3 enters the graduated measuring tube 4 due to the negative pressure [with a graduated The initial height of the solution in the measuring tube 4 is at the 0 scale line], and the reading after the liquid level of the graduated measuring tube 4 stabilizes at a certain height is the system volume V1;

The same test steps as above can be obtained:

The system volume V2 of the second constant temperature measurement line of the constant temperature measurement system C;

The system volume V3 of the third constant temperature measurement line of the constant temperature measurement system C;

The system volume V4 of the fourth constant temperature measurement line of the constant temperature measurement system C.

1.2 Reference chamber volume calibration

Calibration of system volume V5 in reference chamber I38

The volume of the reference chamber I refers to the sum of the volumes of all closed spaces between the six-way valve 79 and the reference chamber I38.

Test steps: open the control valve Ⅲ37, five-way valve Ⅰ80, six-way valve 79, manual valve ⅤⅣ22, manual valve Ⅴ23, close the control valve Ⅰ33, so that the first constant temperature measurement line of the constant temperature measurement system C is the pipeline of the test room volume Ⅰ38 Form a communication control channel with the volume metering system D and the vacuum system E; start the vacuum pump 5, vacuumize to 10Pa, and the solution in the brine container 3 enters the graduated measuring tube 4 due to the negative pressure [in the graduated measuring tube 4 The initial height of the solution is at the 0 scale line], and the reading after the liquid level of the graduated measuring tube 4 stabilizes at a certain height is the system volume V5 of the reference room I;

The same test steps as above can be obtained:

Reference chamber II system volume V6 of constant temperature measurement system C;

Reference chamber III system volume V6 of constant temperature measurement system C;

The reference chamber IV system volume V6 of the constant temperature measuring system C.

1.3 Calibration of core chamber volume

System Volume V9 Calibration of Core Chamber Ⅰ41

The system volume V9 of the core chamber I41 refers to the sum of the volumes of all closed spaces between the six-way valve 79 and the control valve III37, the control valve II and the control valve V. It is the difference between the system volume V1 and the reference room I system volume V5.

That is, the system volume V9 of the core chamber I is equal to the system volume V1 minus the system volume V5 of the reference chamber I;

Obtained in the same way:

The system volume V10 of the core chamber II is equal to the system volume V2 minus the system volume V6 of the reference chamber I;

The system volume V11 of the core chamber III is equal to the system volume V3 minus the system volume V7 of the reference chamber I;

The system volume V12 of the core chamber IV is equal to the system volume V4 minus the system volume V8 of the reference chamber I.

2. Sample canning

The shale samples that have been pretreated to achieve equilibrium moisture are accurately weighed, and quickly loaded into core chambers [namely, core chamber I41, core chamber II52, core chamber III63, and core chamber IV74].

3. Air tightness check

3.1 Inflatable

Fill helium into the first constant temperature measurement line, the second constant temperature measurement line, the third constant temperature measurement line, and the fourth constant temperature measurement line respectively from the gas cylinder I13 [the helium gas in the gas cylinder I13]. The pressure is 2MPa higher than the experimental design pressure.

3.2 Adjust the temperature

Set and adjust the system temperature [adjust the heating system in the incubator through the control cabinet 8 with PLC control board], collect the temperature data of the reference chamber and the core chamber by the temperature sensor, so that the temperature of the core chamber can be stabilized at the temperature required by the experiment.

3.3 Collect data

The display 9 on the control cabinet 8 with a PLC control panel displays the pressure data of the reference chamber and the core chamber, and if the pressure changes within 1 hour do not exceed 1% of the total pressure, the system is deemed to have good airtightness.

4. Determination of the remaining volume of the core chamber

4.1 Determination of remaining volume V13 of core chamber I

The remaining volume V13 of the core chamber I refers to the total volume of the pure shale in the core chamber, including intra-granular pores, inter-granular pores, residual space of the adsorption tank, and connecting pipelines, valves and pressure gauges.

Test steps: Open control valve III37, control valve I34, control valve IV40, six-way valve 79, five-way valve I80, manual valve IV22, vacuum pump 5, and evacuate to 4Pa. Close the six-way valve 79, manual valve IV 22, close the vacuum pump, manual valve V 23, the reading on the measuring tube 4 with scale is the system volume V1' after loading the rock core, and the difference between V1' and the volume V5 of the reference chamber I is the rock volume. Ventricular I41 residual volume V13;

That is, the remaining volume of core chamber I V13 = V1' - V5.

Same method:

The remaining volume of the core chamber II V14= V2'-V6;

The remaining volume of the core chamber III V15= V3'-V7;

The remaining volume of the core chamber IV is V16 = V4' - V8.

5. Isothermal adsorption test

5.1 The reference chamber is filled with methane

Open the gas cylinder II14 [gas cylinder II14 contains methane], open the pressure regulating valve, control valve III37, control valve VIII48, control valve XIII59 and control valve XVIII 70, and send to reference chamber I38, reference chamber II49, reference chamber III60 and reference chamber Fill methane gas into IV71, adjust the pressure in each reference chamber to the set pressure, and record the pressure in each reference chamber as the initial pressure after 10 minutes.

5.2 Fill the sample chamber with methane

After the pressure in each reference chamber is stabilized, open the control valve IV40, control valve IX51, control valve XIV62 and control valve XIX73, fill the core chamber with methane, set and measure 8-10 pressure interval data points within the experimental pressure range , each point is about 1/n of the highest pressure, collect time, pressure and temperature data in each reference chamber and sample chamber.

6. Test of the influence of slick water on the desorption capacity of shale

6.1 Slowly open the corresponding control valve Ⅱ36, control valve Ⅺ47, control valve XVI 58, and control valve XX 69 of each core chamber to release a certain amount of gas respectively. When the pressure of each core chamber reaches the set pressure, close the corresponding control valve of each core chamber Ⅱ36, control valve Ⅺ47, control valve XVI 58, control valve XX 69. At the same time, pay attention to observe whether there is slippery water discharged, and measure the corresponding volume and time.

6.2 After reaching the equilibrium condition, collect relevant data such as time, pressure and temperature of each core chamber.

6.3 Test pressure points one by one from high to low, repeat steps 6.1 and 6.2 until the last pressure point test ends.

7. Data processing

7.1 Rock sample volume

(1) Rock sample volume V17 in core chamber I41

The volume V17 of the rock sample in the core chamber I1 should be the difference between the system volume V5 of the reference chamber I38 and the remaining volume V13 in the core chamber I41. Expressed in the formula as follows:

Rock sample volume in core chamber Ⅰ V17= V5- V13

in the same way;

Rock sample volume in core chamber II V18= V6- V14

Rock sample volume in core chamber II V19= V7- V15

Rock sample volume in core chamber II V20= V8- V16

All volumes above are in ml;

7.2 Adsorption capacity at each pressure point

According to the equilibrium pressure and temperature of each core chamber and each reference chamber, the adsorption amount at different equilibrium pressure points is calculated. Use the following formula:

PV=nZRT

In the formula: p——gas pressure, MPa;

V——gas volume, ml;

n—the number of moles of gas, mol;

Z—compressibility factor of gas, dimensionless;

R——molar gas constant, J·mol-1·K-1;

T——thermodynamic temperature, K.

The number of moles of gas in the core chamber (n1) before equilibrium at each pressure point and the number of moles of gas in the core chamber after equilibrium (n2) are calculated respectively, then the number of moles of gas adsorbed by the core (ni) is:

ni=n1-n2

In the formula: ni—the number of moles of gas, mol;

n1—the number of moles of gas in the core chamber before equilibrium, mol;

n2—the number of moles of gas in the core chamber after equilibrium, mol.

Adsorbed gas volume Vi at each pressure point:

Vi= ni×22.4×1000

The adsorption capacity V adsorption at each pressure point:

Vadsorption = Vi /Gc

In the formula: V adsorption - adsorption capacity, ml/g;

Vi——total volume of adsorbed gas, ml;

Gc—weight of rock sample, g.

7.3 Adsorption amount at the pressure point after desorption

According to the equilibrium pressure and temperature of the reference chamber and the core chamber, the adsorption amount at different pressure points after desorption is calculated. Use the following formula:

PV=nZRT

In the formula: p——gas pressure, MPa;

V——gas volume, ml;

n—the number of moles of gas, mol;

Z—compressibility factor of gas, dimensionless;

R——molar gas constant, J·mol-1·K-1;

T——thermodynamic temperature, K.

The number of moles of gas in the core chamber (n1’) and the number of moles of gas in the core chamber after equilibrium (n2’) at each pressure point are calculated respectively, then the number of moles of gas adsorbed by the core (ni’) is:

ni'= n1'- n2'

In the formula: ni’—the number of moles of gas, mol;

n1’—the number of moles of gas in the core chamber before equilibrium, mol;

n2’—the number of moles of gas in the core chamber after equilibrium, mol.

Adsorbed gas volume Vi' at each pressure point:

Vi'=ni'×22.4×1000

Adsorption amount Vadsorption' at each pressure point:

V Adsorption’ = Vi ’/Gc’

In the formula: Vadsorption’——adsorption capacity, ml/g;

Vi'——total volume of adsorbed gas, ml;

Gc'—weight of rock sample, g.

Gas cylinder III15 was filled with other gases for multiple experiments. The above-mentioned structure can obtain the experimental result only through simple calculation, improves the experimental precision and shortens the experimental cycle.

Apparently, all the above-mentioned embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present invention.

To sum up, due to the above structure, the experimental results can be obtained only by simple calculation, the experimental accuracy is improved and the experimental period is shortened.

Claims (8)

1. a kind of slippery water acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：Including being sequentially connected in series on pipeline Source of the gas feed system（A）, gas boosting storage system（B）, constant temperature measurement system in insulating box（C）, the constant temperature Case is by the switch board with PLC control sheets（8）Control operation；

The gas boosting storage system（B）With constant temperature measurement system（C）Between pipeline on connected by two bypass connecting pipes It is connected to volume measurement system（D）And pumped vacuum systems（E）, the volume measurement system（D）And pumped vacuum systems（E）It is located at respectively The front end of two bypass connecting pipes, the end of two bypass connecting pipes is located at gas boosting storage system（B）Outlet side；

The constant temperature measurement system（C）Outlet side and blow-down pipe（1）Connection；

The source of the gas feed system（A）Include at least one source of the gas supply line again, the source of the gas supply line also includes being sequentially connected in series Gas cylinder, check valve on source of the gas supply pipeline, outlet side and the gas boosting storage system of source of the gas supply pipeline（B）Air inlet End connection；

The gas boosting storage system（B）Include gas boosting pump again（2）With at least one gas boosting line, the gas increasing Line ball also includes being sequentially connected in series surge tank, pressure regulator valve, check valve on gas boosting pipeline；The inlet end of gas boosting pipeline With gas boosting pump（2）Connection, outlet side and the constant temperature measurement system of gas boosting pipeline（C）Inlet end, two sides Lead to the end connection of adapter；The gas boosting pump（2）Inlet end connect with the outlet side of source of the gas supply pipeline；

The constant temperature measurement system（C）Include at least one constant temperature measurement line again, the constant temperature measurement line also includes setting gradually First pressure sensor, the first control valve on constant temperature measurement pipeline, second pressure sensor, the second control valve；First pressure The first bypass pipe is provided with constant temperature measurement pipeline between force snesor and the first control valve, is provided with first bypass pipe 3rd control valve and reference chamber, are fixed on reference to the first TEMP for detecting reference chamber inner chamber temperature on chamber outer wall Device；The second bypass pipe is provided with constant temperature measurement pipeline between the second pressure sensor and the second control valve, this second Be disposed with bypass pipe the 4th control valve, core chamber and the 5th control valve, be fixed on rock core chamber outer wall for detecting The second temperature sensor of core chamber's inner chamber temperature, the 5th control valve and slippery water injected system（F）Slippery water injection The output end connection of pipeline；

The volume measurement system（D）Include being sequentially connected in series in two bypass connecting pipes first bypass connecting pipe again Saline container（3）, have graduated buret（4）With the 5th hand-operated valve, the saline container（3）Positioned at first bypass connecting pipe Foremost；

The pumped vacuum systems（E）It is again true in two bypass connecting pipes second bypass connecting pipe including being sequentially connected in series Empty pump（5）With the 4th hand-operated valve, the vavuum pump（5）Positioned at second bypass connecting pipe foremost；

The slippery water injected system（F）Include that slippery water injects pipeline again, on slippery water injection pipeline middle appearance is provided with Device（6）And injection pump（7）, the injection pump（7）Output end and intermediate receptacle（6）Piston connection in inner chamber；

The source of the gas feed system（A）In check valve, the gas boosting storage system（B）In gas boosting pump（2）, adjust Pressure valve, check valve, the constant temperature measurement system（C）In first pressure sensor, first control valve, second pressure sensor, Second control valve, the 3rd control valve, the first temperature sensor, the 4th control valve, the 5th control valve, second temperature sensor, institute State pumped vacuum systems（E）In vavuum pump（5）, the slippery water injected system（F）In injection pump（7）By controlling with PLC The switch board of film-making（8）Control operation；

The switch board with PLC control sheets（8）On be provided with display（9）With input operation panel（10）.

2. slippery water according to claim 1 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：The gas Source supply system（A）Source of the gas supply line be three, the gas boosting storage system（B）Gas boosting line be three, institute State constant temperature measurement system（C）Constant temperature measurement line be four；

The outlet side of three source of the gas supply lines is by the first cross valve and the gas boosting storage system（B）Gas increase Press pump（2）Inlet end connection；

The inlet end of three gas boosting lines is by the second cross valve and gas boosting pump（2）Outlet side connection, this three The outlet side of bar gas boosting line is by six-way valve and constant temperature measurement system（C）Inlet end, the end of two bypass connecting pipes Connection；

The inlet end of four constant temperature measurement lines is connected by the first five-way valve with six-way valve, on four constant temperature measurement lines 5th control valve is by the second five-way valve and slippery water injected system（F）Slippery water injection pipeline output end connection.

3. slippery water according to claim 1 and 2 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：Institute State source of the gas feed system（A）Gas cylinder and check valve between source of the gas supply pipeline on be provided with hand-operated valve.

4. slippery water according to claim 1 and 2 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：Institute State constant temperature measurement system（C）Core chamber again include tank body（1201）, by tank body（1201）Inner chamber closing lid（1203）, It is fixed on tank body（1201）Intracavity bottom rock core cup（1204）, the rock core cup（1204）External diameter and tank body（1201）It is interior The internal diameter matching in chamber, the rock core cup（1204）Top port be less than tank body（1201）Top port, rock core cup（1204） Top port and tank body（1201）Top port between be formed with inflatable chamber（1205）, rock core cup（1204）Inner chamber be page Rock dust end filled cavity（1206）；The second temperature sensor and inflatable chamber（1205）Or slate flour filled cavity（1206）Even It is logical；

Through lid（1203）The second bypass pipe gas outlet be located at inflatable chamber（1205）In, sequentially pass through tank body（1201）Bottom Plate and rock core cup（1204）The slippery water injected system of base plate（F）Slippery water injection pipeline outlet end fill out positioned at slate flour Fill chamber（1206）In.

5. slippery water according to claim 4 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：The cunning Slip water injected system（F）Slippery water injection pipeline be located at slate flour filled cavity（1206）In pipeline section on be evenly equipped with fluid hole （1207）.

6. slippery water according to claim 1 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：It is described to take out Vacuum system（E）Vavuum pump（5）Vacuum tank is provided with second bypass connecting pipe between the 4th hand-operated valve（11）.

7. slippery water according to claim 1 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：The gas Source supply system（A）In check valve, the gas boosting storage system（B）In pressure regulator valve, check valve, the constant temperature measurement System（C）In first control valve, second control valve, the 3rd control valve, the 4th control valve, the 5th control valve, using battery Valve and by the switch board with PLC control sheets（8）Control is opened and closed.

8. slippery water according to claim 1 acts on lower shale gas desorption aptitude tests instrument, it is characterised in that：The gas Source supply system（A）In check valve, the gas boosting storage system（B）In pressure regulator valve, check valve, the constant temperature measurement System（C）In first control valve, second control valve, the 3rd control valve, the 4th control valve, the 5th control valve, using hydraulic pressure Valve or air pressure valve, the hydraulic valve or air pressure are by corresponding hydraulic pump or pulsometer control keying, the hydraulic pump or pulsometer By the switch board with PLC control sheets（8）Control operation, the hydraulic pump or pulsometer and high-pressure hydraulic source or high pressure pneumatic supply Connection.