A casing cooling test device and test method under ultra-high temperature environment

Abstract

In order to reasonably control the attenuation of the bearing capacity of the production tubing in an ultra-high temperature environment, the present invention proposes a casing cooling test device and test method in an ultra-high temperature environment. The internal temperature of the production tubing is controlled by a heating device, and cooling circulating water is pumped into the outer protection cylinder by a spray device to adjust the temperature of the outer wall of the production tubing. All temperature, pressure, and flow rate regulation changes can be interactively controlled and processed by a data control and processing system, and collected in real time. By analyzing the relationship between the temperature change of the production tubing and the spray time, spray speed, spray hole density, and spray hole spacing, the appropriate spray device model and process parameters are optimized. The test method disclosed in the present invention can simulate the cooling effect of the spray device of ultra-high temperature production wellbore such as underground coal gasification and heavy oil fire drive, realizes the indoor detection, evaluation and optimization of the spray process effect, and at the same time provides test technical support for evaluating the changes in tubing performance after cooling.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production engineering, and relates to a casing cooling test device and a test method under ultra-high temperature environment. Background Art

[0002] Underground coal gasification is a chemical coal mining method that creates appropriate process conditions underground to allow coal to burn in a controlled manner. Through pyrolysis of coal and a series of chemical reactions between coal, oxygen and water vapor, combustible gases such as hydrogen, carbon monoxide and methane are generated, thereby achieving clean coal mining.

[0003] Underground coal gasification is a multidisciplinary, cross-industry disruptive, strategic, and cutting-edge technology with weak basic theories and difficult process technology. The temperature in the combustion zone of the underground coal gasification cavity is as high as 1200°C, and the temperature of the production wellbore fluctuates greatly, which is predicted to reach more than 500°C. In order to avoid deformation and damage such as necking and fracture of the production pipe column caused by high temperature, the bottom temperature of the production well needs to be controlled within the range allowed by the oil casing during the gasification process. The spray process technology is proposed, but how to effectively achieve the cooling effect requires the study of indoor cooling test methods to ensure the safe application of low-alloy carbon steel and provide technical support for the low-cost development of coal gasification.

[0004] In order to ensure the safety of the tubing in the ultra-high temperature environment above 500℃ underground, the existing technology mainly uses high-temperature resistant alloy steel for oil casing, but the cost is relatively high for coal gasification mining; the current indoor high-temperature test cooling method is mainly air cooling or water cooling after heating, and it is impossible to heat and cool simultaneously. For example, the ISO 13679 standard stipulates that the maximum temperature is heated to 180℃ for testing, and then cooled by air cooling or water cooling. Summary of the invention

[0005] The purpose of the present invention is to solve the problems in the prior art of the cooling effect of a tubular column in an ultra-high temperature environment and the inability to evaluate the performance of the tubular column after cooling, and to provide a casing cooling test device and a test method in an ultra-high temperature environment.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A casing cooling test device under ultra-high temperature environment, comprising an outer protection cylinder, a spraying device, a heating device and a temperature and pressure measuring and controlling instrument;

[0008] The outer protective cylinder sleeve is arranged on the outer periphery of the production pipe string, and a drain valve is arranged at the bottom. The two ends of the production pipe string are respectively sealed and connected with the first plugging flange and the second plugging flange;

[0009] The spray device comprises a spray pipe coiled around the outer periphery of the production pipe string and a plurality of spray ports, wherein the plurality of spray ports are arranged on the outer wall of the spray pipe close to the production pipe string, the water inlet of the spray pipe extends to the outer side of the first plugging flange, and the water outlet of the spray pipe extends to the outer side of the second plugging flange;

[0010] The heating device comprises a first heating rod and a second heating rod, wherein the first heating rod is installed in the production tubing string through a first plugging flange; and the second heating rod is installed in the production tubing string through a second plugging flange;

[0011] The temperature and pressure measuring and controlling instrument is installed on the outer wall of the outer protection cylinder, and the detection end extends to the inside of the outer protection cylinder, and is used to detect the temperature and pressure inside the outer protection cylinder and the temperature of the outer wall of the production pipe string.

[0012] A further improvement of the present invention is:

[0013] A first meter is installed at the water inlet of the spray device, and a second meter is installed at the water outlet of the spray device. Both the first meter and the second meter are used to record the temperature and flow rate of the water in the spray device.

[0014] A third meter is installed on the outer wall of the outer protection cylinder to record the temperature and flow of the water in the outer protection cylinder.

[0015] A first needle valve is arranged on the first blocking flange, a second needle valve is arranged on the second blocking flange, and a free end of the first needle valve is connected to a nitrogen bottle.

[0016] The first needle valve is provided with a first temperature and pressure gauge, and the second needle valve is provided with a second temperature and pressure gauge. Both the first temperature and pressure gauge and the second temperature and pressure gauge are used to record the temperature and pressure in the production tubing string.

[0017] It also includes a data control processing system, and the control end of the data control processing system is electrically connected to the first meter, the second meter, the first temperature and pressure gauge, the first heating rod, the second heating rod, the third meter, the second temperature and pressure gauge and the temperature and pressure measurement and control instrument.

[0018] The outer wall of the outer protection cylinder is provided with a safety valve, and the control end of the safety valve is electrically connected with the control end of the temperature and pressure measuring and controlling instrument.

[0019] The spray pipe is a number of U-shaped pipes connected to each other.

[0020] The sprinkler pipe is a coil.

[0021] A test method for a casing cooling test device under an ultra-high temperature environment comprises the following steps:

[0022] Step 1, setting the target external protection cylinder pressure value, the internal temperature of the production tubing string and the outer wall temperature of the production tubing string;

[0023] Step 2, opening the second needle valve, the first needle valve and the nitrogen bottle in sequence, purging the inside of the production string with nitrogen for 5 to 10 minutes, and then closing the second needle valve, the first needle valve and the nitrogen bottle in sequence, and recording the temperature and pressure in the production string through the first temperature and pressure gauge and the second temperature and pressure gauge;

[0024] Step 3, open the water inlet and outlet of the spray device, pump cooling circulating water through the water inlet, close the water outlet after the air in the spray device is exhausted, and record the water flow and temperature at this time through the first meter;

[0025] Step 4, open the drain valve of the outer protection cylinder, record the temperature and flow rate of the water in the outer protection cylinder in real time through the third meter, and adjust the opening of the drain valve until the flow rate displayed on the third meter is the same as the flow rate displayed on the first meter;

[0026] Step 5, turn on the temperature and pressure measuring and controlling instrument to detect the temperature of the outer wall of the production pipe string and the steam pressure in the outer protection cylinder. When the pressure exceeds the set pressure value of the outer protection cylinder, the temperature and pressure measuring and controlling instrument drives the safety valve to automatically release the pressure;

[0027] Step 6, turning on the first heating rod and the second heating rod, controlling the first heating rod and the second heating rod to heat up to a set internal temperature of the production string and keep the temperature constant, and recording the temperature and pressure in the production string through the first temperature and pressure gauge and the second temperature and pressure gauge;

[0028] Step 7, automatically adjusting the water flow rate of the spray device through the temperature transmitted by the temperature and pressure measuring and controlling instrument, increasing the water flow rate when the temperature of the production string is greater than the set outer wall temperature of the production string, and reducing the water flow rate when the temperature of the production string is less than the set outer wall temperature of the production string;

[0029] Step 8, recording the temperature of the production string during the test and the corresponding spraying time, spraying speed, spraying hole density and spraying hole spacing.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The invention discloses a casing cooling test device under ultra-high temperature environment, comprising a production pipe string, a spraying device, a heating device, an outer protection cylinder, a temperature and pressure measuring and controlling instrument and a data control and processing system. The internal temperature of the production pipe string is controlled by the heating device, and cooling circulating water is pumped into the outer protection cylinder by the spraying device to adjust the outer wall temperature of the production pipe string; the water inlet flow of the spraying device is automatically adjusted according to the temperature transmitted by the temperature and pressure measuring and controlling instrument, so that the outer wall temperature of the production pipe string is controlled within an acceptable range; the invention analyzes the relationship between the temperature change of the production pipe string and the spraying time, the spraying speed, the spraying hole density and the spraying hole spacing, and optimizes the applicable spraying device model and process parameters, so as to provide a technical basis for the spraying operation of underground coal gasification.

[0032] The present invention discloses a test method for a casing cooling test device under an ultra-high temperature environment. The internal temperature of the production tubing is controlled by a heating device, and cooling circulating water is pumped into the outer protection cylinder by a spray device to adjust the temperature of the outer wall of the production tubing. All temperature, pressure, and flow rate regulation changes can be interactively controlled and processed by a data control and processing system, and collected in real time. By analyzing the relationship between the temperature change of the production tubing and the spray time, spray speed, spray hole density, and spray hole spacing, the applicable spray device model and process parameters are optimized. The test method disclosed in the present invention can simulate the cooling effect of the ultra-high temperature production wellbore spray device such as underground coal gasification and heavy oil fire drive, realizes the indoor detection, evaluation and optimization of the spray process effect, and at the same time provides test technical support for evaluating the changes in tubing performance after cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of a casing cooling test device under ultra-high temperature environment of the present invention;

[0034] Figure 2 for Figure 1 Sectional view in the AA direction;

[0035] Figure 3 It is a structural schematic diagram of the U-shaped tube of the present invention;

[0036] Figure 4 It is a schematic diagram of the structure of the coil of the present invention.

[0037] Among them: 1-water inlet; 2-first metering meter; 3-first temperature and pressure gauge; 4-first needle valve; 5-nitrogen bottle; 6-first plugging flange; 7-external protection cylinder; 8-first heating rod; 9-spraying device; 10-production tubing string; 11-second heating rod; 12-third metering meter; 13-second plugging flange; 14-second metering meter; 15-water outlet; 16-second needle valve; 17-second temperature and pressure gauge; 18-temperature and pressure measuring and controlling instrument; 19-safety valve; 20-data control and processing system. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0040] like Figure 1 and 2 As shown, the present invention provides a casing cooling test device under ultra-high temperature environment, including an outer protection cylinder 7, a spray device 9, a heating device and a temperature and pressure measuring and controlling instrument 18; the outer protection cylinder 7 is nested in the outer periphery of the production string 10, and a drain valve is arranged at the bottom, and the production string 10 and the two ends of the outer protection cylinder 7 are respectively sealed and connected with a first plugging flange 6 and a second plugging flange 13; the spray device 9 includes a spray pipe coiled around the outer periphery of the production string 10 and a plurality of spray ports, and the plurality of spray ports are arranged on the spray pipe near the production string 10 On the outer wall of one side, the water inlet 1 of the spray pipe extends to the outside of the first sealing flange 6, and the water outlet 15 of the spray pipe extends to the outside of the second sealing flange 13; the heating device includes a first heating rod 8 and a second heating rod 11, and the first heating rod 8 and the second heating rod 11 are respectively screwed into the production tubing 10 through the first sealing flange 6 and the second sealing flange 13; the temperature and pressure measuring and controlling instrument 18 is screwed into the interior from the outer wall of the outer protection cylinder 7, and is used for infrared detection of the temperature and pressure inside the outer protection cylinder 7 and the outer wall temperature of the production tubing 10.

[0041] The first meter 2 and the second meter 14 are respectively installed on the water inlet 1 and the water outlet 15 of the spray device 9, which are used to record the temperature and flow of the water in the spray device 9. The third meter 12 is installed on the outer wall of the outer protection cylinder 7, which is used to record the temperature and flow of the water in the outer protection cylinder 7. The first needle valve 4 and the second needle valve 16 are respectively penetrated on the first plugging flange 6 and the second plugging flange 13, and the free end of the first needle valve 4 is connected to the nitrogen bottle 5. The first needle valve 4 and the second needle valve 16 are respectively provided with a first temperature and pressure gauge 3 and a second temperature and pressure gauge 17, which are used to record the temperature and pressure in the production pipe string 10. The device of the present invention also includes a data control processing system 20, and the control end of the data control processing system 20 is connected to the first meter 2, the second meter 14, the first temperature and pressure gauge 3, the first heating rod 8, the second heating rod 11, the third meter 12, the second temperature and pressure gauge 17 and the temperature and pressure measurement and control instrument 18. The outer wall of the outer protection cylinder 7 is provided with a safety valve 19, which is connected to the control end of the temperature and pressure measuring and controlling instrument 18. The outer wall temperature of the production pipe string is detected in real time through infrared sensing, and the temperature change is recorded. The steam pressure in the outer protection cylinder 7 is monitored by the pressure sensor. When the pressure exceeds the threshold value, the safety valve 19 is driven to automatically release the pressure;

[0042] like Figure 3 As shown, it is a schematic diagram of the structure of the U-shaped tube of the present invention. The spray device 9 includes a spray pipe and a plurality of spray ports wound around the outer periphery of the production pipe string 10. The spray pipe is a plurality of interconnected U-shaped tubes. The water inlet flow of the spray device is automatically adjusted by the temperature transmitted by the temperature and pressure measuring and controlling instrument 19, so that the outer wall temperature of the production pipe string can be controlled within an acceptable range.

[0043] like Figure 4 , which is a schematic diagram of the structure of the coil of the present invention, the spray device 9 includes a spray pipeline coiled around the outer periphery of the production pipe string 10 and a plurality of spray ports, and the spray pipeline is a coil.

[0044] The present invention provides a test method for a casing cooling test device under an ultra-high temperature environment, comprising the following steps: step 1, setting a target outer protection cylinder pressure value, an internal temperature of a production string, and an outer wall temperature of the production string in a data control processing system 20; step 2, sequentially opening a second needle valve 16, a first needle valve 4, and a nitrogen bottle 5, and performing nitrogen purge on the inside of the production string 10 for 5 to 10 minutes, and then sequentially closing the second needle valve 16, the first needle valve 4, and the nitrogen bottle 5, and performing nitrogen purge on the inside of the production string 10 through a first temperature and pressure gauge 3 and a second temperature and pressure gauge 5. Table 17 records the temperature and pressure in the production string 10; Step 3, open the water inlet 1 and the water outlet 15 of the spray device 9, pump cooling circulating water through the water inlet 1, close the water outlet 15 after the air in the spray device 9 is exhausted, and record the flow rate and temperature of the water at this time through the first meter 2; Step 4, open the drain valve of the outer protection cylinder 7, record the temperature and flow rate of the water in the outer protection cylinder 7 in real time through the third meter 12, and adjust the valve opening of the drain valve until the displayed flow rate of the third meter 12 is consistent with that of the first meter 2 The displayed flow rate is basically the same, ensuring that there is no excessive water in the outer protection cylinder 7; Step 5, turn on the temperature and pressure measuring and controlling instrument 18, detect the outer wall temperature of the production pipe string 10 and the steam pressure in the outer protection cylinder 7, when the pressure exceeds the set outer protection cylinder pressure value, the temperature and pressure measuring and controlling instrument 18 drives the safety valve 19 to automatically release the pressure; Step 6, turn on the first heating rod 8 and the second heating rod 11, control the first heating rod 8 and the second heating rod 11 to heat up to the set internal temperature of the production pipe string and keep the temperature constant, through the first temperature and pressure gauge 3 and the second temperature and pressure gauge 17 Record the temperature and pressure in the production string 10; Step 7, automatically adjust the water flow rate of the spray device 9 through the temperature transmitted by the temperature and pressure measuring and controlling instrument 18, increase the water flow rate when the temperature of the production string 10 is greater than T1, and reduce the water flow rate when the temperature of the production string 10 is less than the set production string outer wall temperature; Step 8, analyze the relationship between the temperature change of the production string 10 and the spray time, spray speed, spray hole density and spray hole spacing, and evaluate and optimize the indoor detection of the spray process effect and the change in the performance of the string after cooling.

[0045] The casing cooling test device and test method provided by the present invention under ultra-high temperature environment can simulate the cooling effect of ultra-high temperature production wellbore spraying devices such as underground coal gasification and heavy oil fire drive, realize indoor detection, evaluation and optimization of spraying process effects, and provide test technical support for evaluating changes in pipe string performance after cooling.

[0046] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A casing cooling test method under ultra-high temperature environment, the method is based on a casing cooling test device under ultra-high temperature environment, the test device comprising an outer protection cylinder (7), a spray device (9), a heating device and a temperature and pressure measuring and controlling instrument (18); The outer protection cylinder (7) is sleeved on the outer periphery of the production tubing (10), and a drain valve is arranged at the bottom. The two ends of the production tubing (10) are respectively sealed and connected to a first plugging flange (6) and a second plugging flange (13); a first needle valve (4) is arranged on the first plugging flange (6), a second needle valve (16) is arranged on the second plugging flange (13), and a free end of the first needle valve (4) is connected to a nitrogen bottle (5); a first temperature and pressure gauge (3) is arranged on the first needle valve (4), and a second temperature and pressure gauge (17) is arranged on the second needle valve (16). Both the first temperature and pressure gauge (3) and the second temperature and pressure gauge (17) are used to record the temperature and pressure in the production tubing (10); The spray device (9) comprises a spray pipe coiled around the outer periphery of a production pipe string (10) and a plurality of spray ports, wherein the plurality of spray ports are arranged on the outer wall of the spray pipe close to the production pipe string (10), the water inlet (1) of the spray pipe extends to the outside of the first plugging flange (6), and the water outlet (15) of the spray pipe extends to the outside of the second plugging flange (13); the water inlet (1) of the spray device (9) is equipped with a first meter (2), and the water outlet (15) of the spray device (9) is equipped with a second meter (14), and both the first meter (2) and the second meter (14) are used to record the temperature and flow rate of water in the spray device (9); The heating device comprises a first heating rod (8) and a second heating rod (11); the first heating rod (8) is installed in the production tubing string (10) via a first sealing flange (6); the second heating rod (11) is installed in the production tubing string (10) via a second sealing flange (13); A temperature and pressure measuring and controlling instrument (18) is installed on the outer wall of the outer protective cylinder (7), with a detection end extending into the interior of the outer protective cylinder (7), and is used to detect the temperature and pressure inside the outer protective cylinder (7) and the temperature of the outer wall of the production pipe string (10); a third meter (12) is installed on the outer wall of the outer protective cylinder (7), and is used to record the temperature and flow rate of water in the outer protective cylinder (7); It also includes a data control processing system (20), wherein a control end of the data control processing system (20) is electrically connected to the first meter (2), the second meter (14), the first temperature and pressure gauge (3), the first heating rod (8), the second heating rod (11), the third meter (12), the second temperature and pressure gauge (17), and the temperature and pressure measuring and controlling instrument (18); a safety valve (19) is provided on the outer wall of the outer protection cylinder (7), and the control end of the safety valve (19) is electrically connected to the control end of the temperature and pressure measuring and controlling instrument (18); It is characterized in that The test method comprises the following steps: Step 1, setting the target external protection cylinder pressure value, the internal temperature of the production tubing string and the outer wall temperature of the production tubing string; Step 2, opening the second needle valve (16), the first needle valve (4) and the nitrogen bottle (5) in sequence, purging the interior of the production string (10) with nitrogen for 5 to 10 minutes, then closing the second needle valve (16), the first needle valve (4) and the nitrogen bottle (5) in sequence, and recording the temperature and pressure in the production string (10) using the first temperature and pressure gauge (3) and the second temperature and pressure gauge (17); Step 3, opening the water inlet (1) and the water outlet (15) of the spray device (9), pumping cooling circulating water through the water inlet (1), closing the water outlet (15) after the air in the spray device (9) is exhausted, and recording the flow rate and temperature of the water at this time through the first meter (2); Step 4, opening the drain valve of the outer protective cylinder (7), recording the temperature and flow rate of the water in the outer protective cylinder (7) in real time through the third meter (12), and adjusting the opening of the drain valve until the flow rate displayed on the third meter (12) is the same as the flow rate displayed on the first meter (2); Step 5, turning on the temperature and pressure measuring and controlling instrument (18) to detect the temperature of the outer wall of the production tubing (10) and the steam pressure in the outer protection cylinder (7). When the pressure exceeds the set pressure value of the outer protection cylinder, the temperature and pressure measuring and controlling instrument (18) drives the safety valve (19) to automatically release the pressure; Step 6, turning on the first heating rod (8) and the second heating rod (11), controlling the first heating rod (8) and the second heating rod (11) to heat up to a set internal temperature of the production tubing and keep the temperature constant, and recording the temperature and pressure in the production tubing (10) by means of the first temperature and pressure gauge (3) and the second temperature and pressure gauge (17); Step 7, automatically adjusting the water flow rate of the spray device (9) by the temperature transmitted by the temperature and pressure measuring and controlling instrument (18), increasing the water flow rate when the temperature of the production string (10) is greater than the set temperature of the outer wall of the production string, and reducing the water flow rate when the temperature of the production string (10) is less than the set temperature of the outer wall of the production string; Step 8, recording the temperature of the production tubing string (10) during the test and the corresponding spraying time, spraying speed, spraying hole density and spraying hole spacing.

2. A casing cooling test method under ultra-high temperature environment as claimed in claim 1, characterized in that: The spray pipe is a number of U-shaped pipes connected to each other.

3. A casing cooling test method under ultra-high temperature environment as claimed in claim 1, characterized in that: The sprinkler pipe is a coil.

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