阅读说明：本技术 一种油气井下微波热激解除水相损害的装置与方法 (Device and method for removing water phase damage through oil gas underground microwave thermal shock ) 是由 游利军 王阳 康毅力 唐际锐 陈一健 谢军 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种油气井下微波热激解除水相损害的装置与方法。该装置主要包括安装架、可燃气体检测变送器、双层真空石英内套、特制磁控管、隔热罩、悬吊管、供电系统、氮气系统以及采油树。该方法主要通过磁控管产生微波,加热双层真空石英内套里的水相使其变为高温蒸汽。在热激解除致密砂岩储层水相圈闭损害时开启该装置,然后通过氮气系统向井内加压注入氮气,氮气和双层真空石英内套发生强制对流换热到达储层段后被加热成高温氮气随后经射孔裂缝进入储层,并沿着储层裂缝面将热能带进储层深部。通过上述装置和方法不但可以解除储层的水相圈闭损害还可以利用高温氮气在一定程度上改善储层的渗透性提升致密砂岩气藏的采收率。(The invention discloses a device and a method for removing water phase damage by oil gas underground microwave thermal shock. The device mainly comprises a mounting rack, a combustible gas detection transmitter, a double-layer vacuum quartz inner sleeve, a special magnetron, a heat shield, a suspension pipe, a power supply system, a nitrogen system and a Christmas tree. The method mainly uses a magnetron to generate microwave to heat the water phase in the double-layer vacuum quartz inner sleeve to change the water phase into high-temperature steam. The device is started when the water phase trap damage of the compact sandstone reservoir is removed through heat shock, then nitrogen is injected into the well under pressure through a nitrogen system, the nitrogen and the double-layer vacuum quartz inner sleeve generate forced convection heat exchange to reach the reservoir section, then the nitrogen is heated into high-temperature nitrogen, the high-temperature nitrogen enters the reservoir through the perforation cracks, and heat energy is brought into the deep part of the reservoir along the crack surface of the reservoir. By the device and the method, not only can the water phase trapping damage of the reservoir be relieved, but also the permeability of the reservoir can be improved to a certain extent by utilizing high-temperature nitrogen, and the recovery ratio of the tight sandstone gas reservoir is improved.)

1. The device and the method are characterized in that the heating device comprises an installation rack, a combustible gas detection transmitter, a double-layer vacuum quartz inner sleeve, a special magnetron, a heat shield, a suspension pipe, a power supply system, a nitrogen system and a Christmas tree, wherein the double-layer vacuum quartz inner sleeve is in a pipe column shape, the length of the double-layer vacuum quartz inner sleeve is in direct proportion to the well depth, the outer diameter of the double-layer vacuum quartz inner sleeve is slightly smaller than the diameter of the installation rack, the inner layer vacuum part and the outer layer vacuum part contain water, and the water content is about 1/10 of the volume of the vacuum part and is installed inside a sleeve through the installation rack.

2. The device for microwave thermal shock removal of water phase damage from oil and gas downhole of claim 1, wherein the mounting bracket is made of metal, has a cylindrical shape with a diameter between the inner diameter of the casing and the outer diameter of the double-layer vacuum quartz inner sleeve, and has a top fixed to the wellhead body inside the casing.

3. The microwave thermal shock device for removing water phase damage in oil and gas wells as claimed in claim 1, wherein the purpose-made magnetron is externally provided with a heat shield and is arranged in a double-layer vacuum quartz inner sleeve in a hanging manner through a hanging pipe, and the upper part of the hanging pipe is fixed on the top of the mounting frame.

4. The device for microwave thermal shock removal of water phase damage in oil and gas downhole of claim 1, wherein the power supply system is located at the surface and comprises a cable and a power supply, and the cable is routed from the inside of the hanging pipe to supply power to the special magnetron.

5. The device for microwave thermal stimulation of water phase damage in oil and gas wells as claimed in claim 1, wherein the nitrogen system comprises a nitrogen generator and a booster pump connected by a high pressure pipeline, using mechanical seals.

6. The microwave thermal shock device for removing water phase damage in oil and gas downhole of claim 1, wherein the Christmas tree is installed at a wellhead and is respectively connected with a nitrogen system and a combustible gas detection transmitter through high-pressure pipelines, and the system or the device connected with the Christmas tree adopts mechanical sealing.

7. The method for microwave thermal shock removal of water phase damage in oil and gas downhole according to claim 1, wherein the method is implemented by using the device according to any one of claims 1 to 6, a special magnetron generates microwaves in a well to heat the water phase in a double-layer vacuum quartz inner sleeve to form high-temperature steam, then a nitrogen system pressurizes and injects nitrogen into the well from a well head through a Christmas tree, the nitrogen generates forced convection heat exchange with the double-layer vacuum quartz inner sleeve before reaching a reservoir section at the well bottom to be heated into high-temperature nitrogen, the high-temperature nitrogen enters the reservoir through perforation holes and enters a deep reservoir along the fracture surface of the reservoir, the pressure is kept for injecting the nitrogen when the injection pressure of the nitrogen reaches 1.05-1.10 times of the original reservoir pressure, the gas injection is stopped after a period of time, a power supply is turned off, then the gas return stage is started, and a combustible gas detection transmitter is started at the moment, when the concentration of the natural gas of the flow-back gas reaches a preset standard, the flow-back is considered to be finished, and the damage of water phase trap is removed.

Technical Field

The invention relates to a device and a method for removing water phase damage by microwave thermal shock under oil and gas wells, which can effectively remove water phase trap damage of a compact sandstone reservoir and improve the recovery ratio of a gas reservoir.

Background

China has already stepped into the era of unconventional oil and gas, unconventional natural gas is a general term for natural gas produced outside conventional gas storage layers and is oil and gas developed based on the exploration of the inorganic generation theory of oil and gas. The compact sandstone gas, the shale gas and the coal bed gas are three unconventional natural gases which are recognized in the world and are important fields of global unconventional natural gas exploration and development. With the continuous expansion of the exploitation scale, the dense sandstone gas has become one of the important components of natural gas in China and gradually becomes the main target of unconventional natural gas exploitation. The permeability of the overburden pressure matrix of the compact sandstone gas is generally less than 0.1 multiplied by 10-3 mu m2, and a single well generally has no natural energy or the natural energy is lower than the lower limit of the industrial gas flow, so that the permeability-increasing transformation is generally carried out by hydraulic fracturing in the industrial exploitation stage, but the fracturing fluid cannot be effectively returned and discharged after entering a reservoir, so that a large amount of fracturing fluid is retained in the reservoir to cause water phase trapping damage.

Once water phase trapping damage occurs, economic development of a gas layer can be seriously restricted, reservoir rock and fluid can be actively heated by a reservoir high-temperature heat treatment technology at present, liquid phases in pores are rapidly evaporated, a damage zone is actively discharged, when the heat treatment temperature reaches the thermal cracking threshold temperature of the rock, thermal cracks can be generated, a seepage network is optimized, and the seepage capacity of the reservoir is remarkably improved. It is therefore of great importance to develop an effective downhole heating apparatus and method to relieve or mitigate water entrapment damage.

Compared with the method for exploiting oil and gas by microwave heating of underground oil shale and the simulation experiment system thereof disclosed in Chinese patent publication No. CN 102261238U, the invention uses microwave to heat a shale reservoir, mainly injects a microwave strong absorption medium into the reservoir, so that the reservoir can effectively absorb the microwave and generate heat, and utilizes heat energy to form seams so as to improve the recovery ratio of the shale oil and gas, but the invention does not provide a technical scheme or technical inspiration for solving the problem of water phase trap damage of a tight sandstone reservoir through microwave heating.

Compared with the method and the device for removing the water lock damage of the low-permeability compact sandstone air layer disclosed by the Chinese patent publication No. CN 102536165U, compared with the method and the device, the microwave using objects in the method and the device are different, the using object of the invention is a reservoir, the using object of the invention is a water phase in a double-layer vacuum quartz inner sleeve arranged in a sleeve, compared with the method and the device, the using object of the microwave in the method and the device is different, the using object of the microwave in the invention is directly heating the water phase in the reservoir and is limited by the power of a microwave generator, the heating range of the method is very limited, the using object of the invention is to utilize the microwave to form an in-well heating device to heat nitrogen, finally, the reservoir is heated by utilizing high-temperature nitrogen, and the reservoir range of the high-temperature nitrogen in the reservoir can be heated along with the increase of the injection pressure. In addition, most of the existing well completion modes have metal casings, and metal has the characteristic of shielding microwaves, and the two patents do not provide a solution, so that the limitation of directly using microwaves to heat a reservoir can only be large when the reservoir is completed by using an open hole.

Disclosure of Invention

The invention aims to provide a device and a method for removing water phase damage by microwave thermal shock under oil and gas wells.

The technical scheme adopted by the invention for solving the technical problems is as follows: an apparatus for removing water phase damage by downhole microwave thermal shock of oil and gas, the apparatus comprising: the device comprises a mounting rack, a combustible gas detection transmitter, a double-layer vacuum quartz inner sleeve, a special magnetron, a heat shield, a suspension pipe, a power supply system, a nitrogen system and a Christmas tree.

Further, the method comprises the following steps: the core part of the device for removing the damage of the water phase trap by the underground microwave heat shock is a special magnetron and a double-layer vacuum quartz inner sleeve.

Further, the method comprises the following steps: the special magnetron is used for generating microwave underground, a heat insulation cover is arranged outside the special magnetron, and the special magnetron is arranged in a double-layer vacuum quartz inner sleeve in a suspension mode through a suspension pipe.

Further, the method comprises the following steps: the suspension tube is used for suspending the special magnetron in the double-layer vacuum quartz inner sleeve, the upper part of the suspension tube is fixed at the top of the mounting rack, and a power supply cable is arranged in the suspension tube.

Further, the method comprises the following steps: the double-layer vacuum quartz inner sleeve is in a tubular column shape, the length of the double-layer vacuum quartz inner sleeve is in direct proportion to the well depth, the outer diameter of the double-layer vacuum quartz inner sleeve is slightly smaller than the water content of the inner and outer layers of the diameter of the installation frame, the pressure bearing limit and the required temperature are comprehensively considered, the water content is about 1/10 of the volume of the vacuum part, and the double-layer vacuum quartz inner sleeve is installed inside the sleeve through the installation frame (see the attached drawing 2 in detail).

Further, the method comprises the following steps: the mounting rack is made of metal and used for mounting the double-layer vacuum quartz inner sleeve and the suspension pipe, the outer shape outline of the mounting rack is cylindrical, the diameter of the mounting rack is between the inner diameter of the sleeve and the outer diameter of the double-layer vacuum quartz inner sleeve, and the upper portion of the mounting rack is fixed inside the sleeve of the wellhead main body (see the attached figure 3 in detail).

Further, the method comprises the following steps: the power supply system is positioned on the ground and comprises a cable and a power supply, and the cable is wired from the inside of the suspension pipe to supply power to the special magnetron.

Further, the method comprises the following steps: the nitrogen system comprises a nitrogen generator and a booster pump which are connected through a high-pressure pipeline and are mechanically sealed. Further, the method comprises the following steps: the combustible gas detection transmitter is used for detecting the concentration of combustible gas in the returned gas.

Further, the method comprises the following steps: the Christmas tree is installed at a well head and is respectively connected with the nitrogen system and the combustible gas detection transmitter, the nitrogen system is used for injecting nitrogen into the well in the heating stage, and the flowback gas is discharged from the well head in the flowback stage and is sent to the combustible gas detection transmitter.

The invention also provides a method for removing the water phase trapping damage by oil gas underground heat shock through the device.

Further, the method comprises the following steps: firstly, a downhole heating stage, wherein a special magnetron generates microwaves in a well to heat a water phase in a double-layer vacuum quartz inner sleeve to form high-temperature steam, then a nitrogen system pressurizes and injects nitrogen into the well from a well mouth through a Christmas tree, the nitrogen and the double-layer vacuum quartz inner sleeve generate forced convection heat exchange before reaching a reservoir section at the bottom of the well and are heated into high-temperature nitrogen, the high-temperature nitrogen enters a reservoir layer through a perforation hole and enters the deep part of the reservoir layer along the fracture surface of the reservoir layer, the pressure is kept for injecting gas when the injection pressure of the nitrogen reaches 1.05-1.10 times of the pressure of the original reservoir layer, the gas injection is stopped after a period of time, and a power supply is turned off.

Further, the method comprises the following steps: and (4) entering a flowback stage after the underground heating stage is finished, starting the combustible gas detection transmitter at the moment, and when the concentration of the natural gas of the flowback gas reaches a preset standard, determining that flowback is finished and the damage of water phase trap is relieved.

The invention has the advantages and beneficial effects that:

1. compared with other underground heating devices, the underground heating device has low power consumption, saves energy, does not need to continuously supply power for a long time, and has good economy;

2. compared with other underground heating devices, the underground heating device does not need to supply power to a deep well at high voltage, and the only power consumption device in the underground heating device is a special magnetron with low power, so that the underground heating device has good safety;

3. compared with other underground heating devices, the underground heating device has a simple structure and is easy to manufacture, so that the manufacturing and maintenance cost is very low;

4. compared with other underground heating methods, the underground heating method has the advantages that the nitrogen is already high-temperature nitrogen when reaching the underground reservoir section, so that cold damage to the reservoir caused by the gas entering the reservoir from the first wave in other heating methods for directly injecting hot dry gas from the well mouth is effectively avoided;

5. compared with other underground heating methods, the underground heating method has the advantages that the temperature reaches the temperature required by the reservoir heating when the nitrogen reaches the reservoir section, so that the long preheating period of the conventional heat injection dry gas heating reservoir is avoided, and the heating efficiency is effectively improved.

Drawings

FIG. 1 is a flow chart of the present invention in the well site construction process

In the figure: 1. the device comprises a booster pump, a nitrogen generator, a nitrogen system, a combustible gas detection transmitter, a Christmas tree, a mounting frame, a hanging pipe, a sleeve, a special magnetron, a heat shield, a double-layer vacuum quartz inner sleeve, a reservoir section, a perforation crack, a cable and a power supply system, wherein the nitrogen generator is 2, the nitrogen system is 3, the combustible gas detection transmitter is 4, the Christmas tree is 5, the mounting frame is 6, the hanging pipe is 7, the sleeve is 8, the special magnetron is 9, the heat shield is 10, the double-layer vacuum quartz inner sleeve is 11, the reservoir section is 12, the perforation crack is 13, the cable is 14, and the power supply system is 15.

FIG. 2 is a visual and top view of a double-layer vacuum quartz inner sleeve

In the figure: 16. inner layer, 17, outer layer, 18, water phase.

FIG. 3 is a pictorial view of a mount

In the figure: 19. top fixture, 20. hanging pipe fixing position.

Detailed Description

The invention will be further explained with reference to the drawings.

See fig. 1, fig. 2, fig. 3.

A heating stage: in the stage, firstly, a mounting frame 6 is fixedly mounted through the upper part, then a double-layer vacuum quartz inner sleeve 11 is mounted on the mounting frame 6, a special magnetron 9 provided with a heat insulation cover 10 is hung at a hanging pipe fixing position 20 at the top of the mounting frame 6 through a hanging pipe 7, then a Christmas tree 5 is mounted to a wellhead, a nitrogen system 3 is hermetically connected with the Christmas tree 5, finally, a power supply system 15 is started to electrify the special magnetron 9, the nitrogen system 3 is started to inject nitrogen into a well through the Christmas tree 5 in a pressurized mode, the nitrogen is changed into high-temperature nitrogen to enter a reservoir through a perforation crack 13 after reaching a reservoir section 12, the nitrogen is stopped to be injected when the injection pressure reaches 1.05-1.10 times of the original reservoir, the power supply system 15 is closed, and then the stage of back drainage is started.

A flow-back stage: in the stage, the combustible gas detection transmitter 4 is firstly opened and is in sealed connection with the flowback channel in the Christmas tree 5, then the concentration of natural gas in the flowback gas is detected, when the concentration of the natural gas in the flowback gas reaches a preset standard, the flowback is considered to be finished, and the damage of water phase trap is relieved.