Method for improving shale oil reservoir recovery efficiency by injecting air in cooperation with electric pulse and experimental device

Abstract

The application provides a method and experimental device for improving shale oil reservoir recovery by air injection combined with electric pulse, air injection technology is combined with high-voltage electric pulse technology, air injected into a reservoir is ionized under the action of high-frequency electricity, jumps to an excited state, the oxidation reaction activity with organic matter in the reservoir is enhanced, stress waves released by high-frequency electricity act on a shale matrix, micro-cracks in the matrix are expanded, the action range of excited-state particles is enhanced, more reservoir organic matter is caused to participate in the oxidation reaction, the oxidation heat effect is improved, excited-state charged particles can form 'ion wind' to send flue gas generated by combustion into an un-reached area through a complex crack network structure newly formed under the synergistic effect, and the heat spreading range is enhanced. The method and experimental device for improving shale oil reservoir recovery by air injection combined with electric pulse provided by the application reduce energy consumption and cost, reduce environmental pollution, and improve the recovery rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shale oil development, in particular to a method for improving shale oil reservoir recovery rate by air injection and electric pulse and an experimental device. BACKGROUND

[0002] China is rich in shale oil resources and has great development potential. According to the evaluation of EIA, the technically recoverable reserves of shale oil in China are 322 billion barrels (about 45 x 10 8 The shale oil reservoir has poor reservoir properties and is rich in solid organic matter, and the flowability of the reservoir retained hydrocarbon is poor, so it is difficult to develop by conventional methods. In recent years, high-frequency electric pulse technology has been applied to the hole expansion and permeability increase of tight reservoirs. Compared with traditional fracturing, combustion and other technologies, this method has the characteristics of environmental friendliness, simple construction, high rock breaking efficiency, etc. However, there are some problems in application, such as the need to continuously apply high voltage to the formation to break the plasma channel, high energy consumption, high cost, environmental pollution, limited effective action distance, etc. Therefore, it is necessary to design a method for improving shale oil reservoir recovery rate by air injection and electric pulse and an experimental device. SUMMARY

[0003] The purpose of the present application is to provide a method for improving shale oil reservoir recovery rate by air injection and electric pulse and an experimental device, which can combine high-voltage pulse technology and air injection technology, reduce energy consumption and cost, reduce environmental pollution, and improve recovery rate.

[0004] To achieve the above-mentioned purpose, the present application provides the following scheme:

[0005] A method for improving shale oil reservoir recovery rate by air injection and electric pulse, comprising the following steps:

[0006] Step 1: A pair of upper and lower parallel double horizontal wells are arranged in the target reservoir, electrodes are arranged in the horizontal wells, the electrodes are connected with the ground power supply equipment through a cable, and the target reservoir is subjected to primary fracturing by high-frequency electricity;

[0007] Step 2: Air is injected into the target reservoir, and the pressure of the target reservoir is monitored, and when the pressure reaches a first preset pressure threshold, the air injection is stopped;

[0008] Step 3: Soak well operation is carried out, and the temperature of the target reservoir is monitored, if the target reservoir is lower than the first preset temperature threshold, high-frequency voltage is applied to the double horizontal wells, and when the temperature of the target reservoir rises to a third preset temperature threshold, the target reservoir is intermittently radiated by low-frequency electricity;

[0009] Step 4: If the temperature of the target reservoir is higher than the second preset temperature threshold, medium-frequency electricity is applied to the target reservoir, and whether the current changes is observed by an oscilloscope, if the current is generated, the target reservoir is intermittently radiated by low-frequency electricity;

[0010] Step 5: Real-time monitoring of the concentration of O2 in the produced gas of the production well, if the concentration is lower than the first preset concentration threshold, then the well is opened for depletion production, and when the target reservoir temperature is lower than the first preset temperature threshold, the production is stopped;

[0011] Step 6: Setting a heat energy conversion device on the ground, inputting the produced oil and gas into the heat energy conversion device, and converting heat energy to store electric energy for ground power equipment;

[0012] Step 7: Starting the next round of huff and puff, wherein the soak time is set to 1-1.5 times of the previous cycle;

[0013] Step 8: Performing multiple rounds of huff and puff according to steps 2-7.

[0014] Optionally, the first preset temperature threshold is 150℃, the second preset temperature threshold is 250℃, and the third preset temperature threshold is 300℃.

[0015] Optionally, the first preset pressure threshold is 1-1.5 times of the original formation pressure.

[0016] Optionally, the first preset concentration threshold is 5%.

[0017] The application also provides an experimental device for improving shale oil reservoir recovery by air injection and electric pulse, which is applied to the method for improving shale oil reservoir recovery by air injection and electric pulse, and comprises a high-temperature pulse rock breaking system, an electrode, a flowmeter, a high-temperature high-pressure reaction device, a gas-liquid separator, a liquid collection bottle, a gas collection bottle, an air compressor, a gas analyzer and a data acquisition box. The air compressor is connected with the gas storage tank through a pressure gauge and a first six-way valve, the gas storage tank is connected with the flowmeter, the flowmeter is connected with a second six-way valve which is connected with the input end of the high-temperature high-pressure reaction device, the pressure gauge is arranged on the second six-way valve, the high-temperature high-pressure reaction device is internally provided with a core, the electrode is connected with the two sides of the core by penetrating the input end and the output end of the high-temperature high-pressure reaction device, the output end of the high-temperature high-pressure reaction device is connected with the input end of the gas-liquid separator, the gas outlet end and the liquid outlet end of the gas-liquid separator are respectively connected with the gas collection bottle and the liquid collection bottle, the gas collection bottle is connected with the gas analyzer, and the high-temperature high-pressure reaction device is further provided with an electric igniter and a thermocouple.

[0018] According to the specific embodiments of the present application, the following technical effects are disclosed: the method and experimental device for improving the recovery rate of shale oil reservoirs by injecting air in cooperation with electric pulses, which combines the air injection technology with the high-voltage electric pulse technology, under the action of high-frequency electricity, the injected air is ionized and jumps to a high-energy state, enhancing the combustion activity of organic matter in the reservoir, the stress waves released by high-frequency electricity act on the shale matrix, causing the expansion of micro-cracks in the matrix, enhancing the action range of the excited-state particles, prompting more reservoir organic matter to participate in the oxidation reaction, improving the oxidation heat effect, thereby enhancing the thermal cracking of the reservoir rock minerals, prompting the expansion of the shale crack-matrix structure, enhancing the complex structure of the underground fracture network, improving the reservoir conductivity, the oxidation heat energy cracking effect is obvious, without the need for continuous application of high-frequency voltage, reducing energy consumption, the ion wind generated during the discharge process can send active particles, air and flue gas into the un-reached area through the newly formed complex fracture network structure, improve the exhaust gas temperature, expand the area range of the highest temperature, thereby promoting combustion and reducing the emission of harmful gases. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The flowchart of the method for improving the recovery rate of shale oil reservoirs by injecting air in cooperation with electric pulses according to the embodiments of the present application is shown in the figure.

[0021] Figure 2 The structure diagram of the experimental device for improving the recovery rate of shale oil reservoirs by injecting air in cooperation with electric pulses according to the embodiments of the present application is shown in the figure.

[0022] Figure 3 The recovery rate diagram of different rounds of air injection huff and puff, high-voltage electric pulse and air injection huff and puff in cooperation with high-voltage pulse huff and puff according to the embodiments of the present application is shown in the figure.

[0023] Figure 4 The micro-SEM diagram of shale after air huff and puff is shown in the figure.

[0024] Figure 5 The micro-SEM diagram of shale after high-voltage electric pulse is shown in the figure.

[0025] Figure 6 The micro-SEM diagram of shale after air huff and puff in cooperation with high-voltage electric pulse is shown in the figure. DETAILED DESCRIPTION

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The purpose of this invention is to provide a method and experimental apparatus for improving the recovery rate of shale oil reservoirs by combining air injection with electrical pulses. This method combines high-pressure pulse technology and air injection technology, thereby reducing energy consumption and costs, mitigating environmental pollution, and improving the recovery rate.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 As shown in the embodiment of the present invention, the method for enhancing the recovery rate of shale oil reservoirs by air injection combined with electrical pulses includes the following steps:

[0030] Step 1: Set up a pair of parallel horizontal wells in the target reservoir, install electrodes in the horizontal wells, connect the electrodes to the surface power equipment through cables, and perform primary fracturing of the target reservoir through high-frequency electricity.

[0031] Step 2: Inject air into the target reservoir and monitor the pressure of the target reservoir. When the pressure reaches the first preset pressure threshold, stop injecting air.

[0032] Step 3: Perform well shut-off operation and monitor the target reservoir temperature. If the target reservoir temperature is lower than the first preset temperature threshold, apply high-frequency voltage to the dual horizontal well to ionize the air in the current block and quickly generate a large number of excited-state particles, which enhance the oxidation reaction activity with the organic matter in the reservoir. During this process, the stress wave released by the high-frequency voltage acts on the shale matrix, causing the micro-fractures in the matrix to expand, which enhances the range of action of the excited-state particles, prompts more reservoir organic matter to participate in the oxidation reaction, and enhances the oxidation heat effect.

[0033] When the target reservoir temperature rises to the third preset temperature threshold, the target reservoir is irradiated with low-frequency electrical intermittents.

[0034] Step 4: If the target reservoir temperature is higher than the second preset temperature threshold, apply medium frequency electricity to the target reservoir to promote the rapid formation of ion wind. Observe whether the current changes through an oscilloscope. If current is generated, irradiate the target reservoir intermittently with low frequency electricity.

[0035] Under the action of ion wind, flue gas (N2, CO2, etc.) generated by combustion in the shale reservoir enters the block not affected by thermal effect through the complex fracture network formed under the action of oxidation heat effect, so as to enhance the thermal utilization rate and improve the thermal effect area. In addition, under the action of high temperature and high pressure, the flue gas may form a supercritical multi-component thermal fluid, so as to enhance the extraction of organic matter in the reservoir in the adsorbed state and the mutual solubility state, and achieve the effect of improving the recovery rate.

[0036] Ion wind is also known as "electrohydrodynamics (EHD)", which is the collision ionization of gas under the action of high voltage to produce charged particles. The charged particles are accelerated under the action of electric field, and will collide with air molecules in the movement process, resulting in momentum exchange. At present, this technology has been introduced into the combustion supporting field and enhanced the combustion effect through the following aspects: 1) Plasma provides high-energy particles to excite neutral components such as nitrogen and oxygen to high-energy state, so as to accelerate the reaction or establish a new reaction path, so as to achieve the purpose of enhancing the combustion effect; 2) The high-energy ions provided by the plasma form an electric field, so as to intensify the fragmentation of the fuel, so as to enhance the contact probability of the fuel and air;

[0037] Step 5: Real-time monitoring of the concentration of O2 in the produced gas of the production well, if the concentration is lower than the first preset concentration threshold, then the well is opened for depletion production, and when the temperature of the target reservoir is lower than the first preset temperature threshold, the production is stopped.

[0038] Step 6: Setting a heat energy conversion device on the ground, inputting the produced oil and gas into the heat energy conversion device, and converting heat energy to store electric energy for ground power equipment;

[0039] Step 7: Start the next round of huff and puff, wherein the soak time is set to 1-1.5 times of the previous cycle;

[0040] Step 8: Perform multiple rounds of huff and puff according to steps 2-7.

[0041] The first preset temperature threshold is 150℃, the second preset temperature threshold is 250℃, and the third preset temperature threshold is 300℃.

[0042] The first preset pressure threshold is 1-1.5 times of the original formation pressure.

[0043] The first preset concentration threshold is 5%.

[0044] The method combines air injection technology and high-voltage electric pulse technology, under the action of high-frequency electricity, the injected air is ionized and jumps to a high-energy state, enhancing the combustion activity of organic matter in the reservoir;At the same time, the stress wave released by high-frequency electricity acts on the shale matrix, causing the microcracks in the matrix to expand, enhancing the action range of the excited state particles, prompting more reservoir organic matter to participate in the oxidation reaction, improving the oxidation heat effect, thereby enhancing the thermal cracking of the reservoir rock minerals, promoting the expansion of the shale crack-matrix structure, enhancing the complex structure of the underground fracture network, improving the reservoir conductivity, and the oxidation heat energy cracking effect is obvious, without the need for continuous application of high-frequency voltage, thereby reducing energy consumption;

[0045] The ion wind generated during the discharging process can send active particles, air and flue gas into the un-reached area through the newly formed complex fracture network structure, improve the waste gas temperature, expand the area range of the highest temperature, thereby promoting combustion and reducing harmful gas emissions.

[0046] As shown in Figure 2 The present application also provides an experimental device for improving the recovery of shale oil reservoirs by air injection and electric pulse, which is applied to the method for improving the recovery of shale oil reservoirs by air injection and electric pulse, comprising: a high-temperature pulse rock breaking system, an electrode, a flowmeter, a high-temperature high-pressure reaction device, a gas-liquid separator, a liquid collection bottle, a gas collection bottle, an air compressor, a gas analyzer and a data acquisition box, the air compressor is connected with the gas storage tank through a pressure gauge and a first six-way valve, the gas storage tank is connected with the flowmeter, the flowmeter is connected with a second six-way valve which is connected with the input end of the high-temperature high-pressure reaction device, the pressure gauge is arranged on the second six-way valve, the high-temperature high-pressure reaction device is internally provided with a core, the electrode is connected with the two sides of the core through the input end and the output end of the high-temperature high-pressure reaction device, the output end of the high-temperature high-pressure reaction device is connected with the input end of the gas-liquid separator, the gas outlet end and the liquid outlet end of the gas-liquid separator are respectively connected with the gas collection bottle and the liquid collection bottle, the gas collection bottle is connected with the gas analyzer, and the high-temperature high-pressure reaction device is further provided with an electric igniter and a thermocouple;

[0047] The high-temperature high-pressure reaction device comprises a combustion tube body, a temperature and pressure monitoring system, an ignition system, an output gas analysis module and the like;

[0048] The high-temperature pulse rock breaking system comprises an energy storage module, a charging power supply, a triggering system and the like.

[0049] The use process of the device is specifically as follows:

[0050] The high-voltage electric pulse experiment is carried out: the igniter in the high-temperature and high-pressure reaction device is closed, the natural fracture core saturated with oil is put into the high-temperature and high-pressure reaction device, and the electrodes are connected to the two sides of the core from the input end and the output end of the high-temperature and high-pressure reaction device respectively, and after ensuring the tight connection, 5 MPa confining pressure is applied; the charging switch is opened, and the voltage is raised by 220 V alternating current (the transformer ratio is set to 1000:1); during the voltage rising process, the current is adjusted by the high-voltage silicon stack, so that the alternating current becomes direct current and is stored in the energy storage module, after the charging is completed, the trigger system is opened, the discharge circuit is connected, the instantaneous high-energy electricity in the energy storage unit is applied to the two ends of the electric shock (the charging and discharging rated voltage is set to 0.01-50 kV), and after 10 times of electric shock, the high-frequency electric pulse system is closed and the outlet end is opened for production, when there is no shale oil flowing out of the outlet end, the output oil volume is recorded and the next round of high-voltage electric pulse experiment is carried out, and the cumulative impact is 5 rounds;

[0051] The air injection and huff and puff experiment is carried out: the electrodes at both ends of the high-temperature and high-pressure reaction device are removed and the high-frequency voltage output system is closed, the natural fracture core saturated with oil is put into the high-temperature and high-pressure reaction device, and 5 MPa confining pressure is applied; air is injected into the high-temperature and high-pressure reaction device at an injection rate of 0.5 mL / min, and the data acquisition system is observed, and when the pressure continues to rise, the air injection is stopped; the injection valve is closed, the igniter is opened, and whether a combustion chamber (temperature > 350 DEG C) is formed is observed by the data acquisition system, if a stable combustion chamber is formed, the igniter is closed; after stewing for 3 h, the O2 content in the produced gas is monitored, if it is lower than 5%, the outlet end is opened for 1 h for oil production, and the air injection and huff and puff production degree is calculated; the next round of air injection and huff and puff is carried out according to the above steps, and the cumulative huff and puff is 5 rounds;

[0052] The air injection and huff and puff assisted high-voltage electric pulse experiment is carried out: the igniter and the high-frequency electric pulse system in the high-temperature and high-pressure reaction device are opened, the natural fracture core saturated with oil is put into the high-temperature and high-pressure reaction device, and the electrodes are connected to the two sides of the core from the input end and the output end of the high-temperature and high-pressure reaction device respectively, and after ensuring the tight connection, 5 MPa confining pressure is applied; air is injected into the high-temperature and high-pressure reaction device at an injection rate of 0.5 mL / min, and the data acquisition system is observed, and when the pressure continues to rise, the air injection is stopped; the igniter is opened, and whether a combustion chamber (temperature > 350 DEG C) is formed is observed by the data acquisition system, if a stable combustion chamber cannot be formed, the reservoir unit shocks the core with 40 kV high-frequency electricity; if a stable combustion chamber (temperature > 350 DEG C) can be formed, the energy storage unit shocks the core with 10 kV low-frequency electricity, after stewing for 3 h, the O2 content in the produced gas is monitored, if it is lower than 5%, the outlet end is opened for 1 h for oil production, and the air injection and huff and puff assisted high-voltage electric pulse production degree is calculated; the next round is carried out according to the above steps, and the cumulative experiment is 5 rounds.

[0053] By Figure 3It can be seen that the first round of air huff and puff, high-voltage electric pulse and air huff and puff assisted high-voltage electric pulse huff and puff recovery rates are 21.4%, 23.4% and 27.5% respectively; the second round of huff and puff recovery rates are 16.4%, 13.5% and 18.7% respectively; the third round of huff and puff recovery rates are 8.2%, 4.4% and 12.5% respectively; the fourth round of huff and puff recovery rates are 3.1%, 2.1% and 6.9% respectively; the fifth round of huff and puff recovery rates are 1.1%, 0.3% and 2.8% respectively. It can be seen that after the first round of huff and puff, the high-voltage electric pulse huff and puff recovery rate is higher than that of air huff and puff, which may be because the high-voltage rock breaking efficiency is higher than the oxidation heat effect, so the shale micro-pore structure expansion degree under high-voltage electric pulse is high; and when the huff and puff round reaches the second round, the air huff and puff recovery rate is higher than that of high-voltage electric pulse, which is because under the action of oxidation heat, part of the solid organic matter in the shale is converted into oil and gas, so the recovery degree is improved. When the huff and puff round reaches the fourth round, the air huff and puff recovery degree is still higher than 5% in cooperation with high-voltage electric pulse, so it is considered that the air huff and puff assisted high-voltage electric pulse method has a good effect on improving the recovery degree.

[0054] The micro-morphology of shale after air huff and puff, high-voltage electric pulse and air huff and puff assisted high-voltage electric pulse huff and puff is observed by scanning electron microscope, as shown in FIGS. 1-3. Figures 4-6 As shown in FIGS. 1-3, it can be found that after air huff and puff, the surface of shale is dissolved, and part of the "hidden fracture" develops inside; after high-voltage electric pulse, the surface of shale is not dissolved, and a small amount of crack structure appears on the surface; part of the rock on the surface is eroded; after air huff and puff assisted high-voltage electric pulse, the surface of shale is in a dissolved state and develops obvious crack structure.

[0055] The method for improving the recovery rate of shale oil reservoir by air injection combined with electric pulse and the experimental device provided by the present application combine the air injection technology and the high-voltage electric pulse technology, under the action of high-frequency electricity, the injected air is ionized and jumps to a high-energy state, enhancing the combustion activity of organic matter in the reservoir, the stress wave released by high-frequency electricity acts on the shale matrix, causing the micro-fracture in the matrix to expand, enhancing the action range of the excited state particles, promoting more reservoir organic matter to participate in the oxidation reaction, improving the oxidation heat effect, thereby enhancing the thermal-induced cracking of the rock minerals in the reservoir, promoting the expansion degree of the shale fracture-matrix structure, enhancing the complex structure of the underground fracture network, improving the conductivity of the reservoir, the oxidation heat energy-induced cracking effect is obvious, without the need for continuous application of high-frequency voltage, the energy consumption is reduced, the ion wind generated in the discharge process can send active particles, air and flue gas into the un-impinged area through the newly formed complex fracture network structure, improve the temperature of the exhaust gas, expand the area range of the highest temperature, thereby promoting combustion and reducing the emission of harmful gases.

[0056] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A method for enhancing the recovery rate of shale oil reservoirs through air injection combined with electrical pulses, characterized in that, Includes the following steps: Step 1: Set up a pair of parallel horizontal wells in the target reservoir, install electrodes in the horizontal wells, connect the electrodes to the surface power equipment through cables, and perform primary fracturing of the target reservoir through high-frequency electricity. Step 2: Inject air into the target reservoir and monitor the pressure of the target reservoir. When the pressure reaches the first preset pressure threshold, stop injecting air. Step 3: Perform well shut-off operation and monitor the target reservoir temperature. If the target reservoir temperature is below the first preset temperature threshold, apply high-frequency voltage to the dual horizontal well. When the target reservoir temperature rises to the third preset temperature threshold, irradiate the target reservoir with low-frequency electricity intermittently. Step 4: If the target reservoir temperature is higher than the second preset temperature threshold, apply medium frequency electricity to the target reservoir and observe whether the current changes through an oscilloscope. If a current is generated, intermittently radiate low frequency electricity to the target reservoir. Step 5: Monitor the concentration of O2 in the gas produced by the production well in real time. If the concentration is lower than the first preset concentration threshold, start the well for depletion production. Stop production when the target reservoir temperature is lower than the first preset temperature threshold. Step 6: Install a thermal energy conversion device on the ground, input the produced oil and gas into the thermal energy conversion device for thermal energy conversion, and store electrical energy for ground power equipment; Step 7: Start the next round of throughput, where the well-closing time is set to 1-1.5 times that of the previous cycle; Step 8: Perform multiple rounds of throughput as per steps 2-7.

2. The method for enhancing shale oil recovery by air injection combined with electrical pulses according to claim 1, characterized in that, The first preset temperature threshold is 150℃, the second preset temperature threshold is 250℃, and the third preset temperature threshold is 300℃.

3. The method for enhancing shale oil recovery by air injection combined with electrical pulses according to claim 1, characterized in that, The first preset pressure threshold is 1 to 1.5 times the original formation pressure.

4. The method for enhancing shale oil recovery by air injection combined with electrical pulses according to claim 1, characterized in that, The first preset concentration threshold is 5%.

5. An experimental apparatus for enhancing the recovery rate of shale oil reservoirs by air injection combined with electrical pulses, applied to the method for enhancing the recovery rate of shale oil reservoirs by air injection combined with electrical pulses as described in any one of claims 1-4, characterized in that, include: The system comprises a high-temperature pulse rock breaking system, electrodes, a flow meter, a high-temperature and high-pressure reaction device, a gas-liquid separator, a liquid collection bottle, a gas collection bottle, an air compressor, a gas analyzer, and a data acquisition box. The air compressor is connected to a gas storage tank via a pressure gauge and a first six-way valve. The gas storage tank is connected to the flow meter. The flow meter is connected to the input end of the high-temperature and high-pressure reaction device via a second six-way valve. The pressure gauge is mounted on the second six-way valve. A rock core is located inside the high-temperature and high-pressure reaction device. The electrodes pass through the input and output ends of the high-temperature and high-pressure reaction device and are connected to both sides of the rock core. The output end of the high-temperature and high-pressure reaction device is connected to the input end of the gas-liquid separator. The gas outlet and liquid outlet of the gas-liquid separator are connected to the gas collection bottle and the liquid collection bottle, respectively. The gas collection bottle is connected to the gas analyzer. The high-temperature and high-pressure reaction device is also equipped with an electric igniter and a thermocouple.

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