WO2020030043A1 - 一种油井高压气体冲压装置及方法 - Google Patents

一种油井高压气体冲压装置及方法 Download PDF

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WO2020030043A1
WO2020030043A1 PCT/CN2019/099789 CN2019099789W WO2020030043A1 WO 2020030043 A1 WO2020030043 A1 WO 2020030043A1 CN 2019099789 W CN2019099789 W CN 2019099789W WO 2020030043 A1 WO2020030043 A1 WO 2020030043A1
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Prior art keywords
oil well
pressure gas
liquid
oil
pressure
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PCT/CN2019/099789
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English (en)
French (fr)
Inventor
张朝纯
张晓�
郑毅
曹溪
王悦
张忠涛
杨智光
高德利
孙冰
张凤林
金葵
黄弘森
孙兴明
韩宝忠
文屹
钟明
贺群
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鞍山万维科技有限公司
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Publication of WO2020030043A1 publication Critical patent/WO2020030043A1/zh

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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/08—Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure
    • E21B21/085—Underbalanced techniques, i.e. where borehole fluid pressure is below formation pressure

Definitions

  • the invention belongs to oil recovery engineering technology, and particularly relates to an oil well high-pressure gas stamping device and method.
  • a typical device uses a pumping pump to deliver fluid from an oil well to the surface.
  • the fluid level in a well directly affects the production of oil wells.
  • the recoverable reserves are usually 60% smaller than the proven reserves, which is the biggest pain point of mechanical fluid recovery.
  • the oil produced often does not reach 1% of the amount of liquid produced.
  • coalbed methane, associated gas in oil production wells, and shale gas are very expensive energy sources, but mechanical fluid extraction cannot be used for mining, which is also a technical problem to be solved.
  • associated gas in the reservoir because it has a smaller density, is always suppressed by the natural pressure generated by the liquid column generated in the well, and cannot be released.
  • the purpose of the present invention is to provide a technical solution for a high-pressure gas stamping device and method for an oil well, which can improve the recovery rate and the efficiency of the oil well, and fully exploit the resources of the oil well.
  • the technical solution of the present invention is: an oil well high-pressure gas stamping device; the device includes an energy storage tank, a gas jet pipe, and a collector, and the gas jet pipe extends from the wellhead of the oil well into the oil well, and A high-pressure gas is stored in the energy storage tank, and the gas injection pipe is connected to the energy storage tank through a pipeline.
  • the collector is a collector that collects liquid in the oil well, and the collector is connected to the wellhead of the oil well.
  • the air jet pipe extends into the bottom of the oil well, and the front end of the air jet pipe is provided with a pulse pressure control which opens when the set pressure is reached.
  • the collector is connected to the wellhead casing outlet of the oil well, and the air jet pipe is connected to a high-pressure water pipe that inputs high-pressure water through a tee.
  • a preferred device configuration is that the energy storage tank is not less than 20 cubic meters, and the gas pressure in the energy storage tank is 35 MPa.
  • a high-pressure gas stamping oil recovery method for an oil well includes:
  • high pressure gas is injected into the oil well from the bottom of the oil well, and the pressure of the high pressure gas is not less than twice the internal pressure of the liquid at the bottom of the oil well, and the high pressure gas is nitrogen
  • the liquid is separated in a collector for oil, water and sediment.
  • An oil well oil well high pressure gas punching dredging method includes:
  • High-pressure gas is sprayed to the bottom of the oil well to drive the liquid in the well from the wellhead; then water is added to the high-pressure gas, and the volume fraction of the high-pressure gas to water is 7: 3; water-containing high-pressure gas is sprayed to the bottom of the oil well.
  • the water horsepower is used to drive mud and sand in the oil well from the wellhead casing. After no mud or sand is seen in the gas stream ejected from the wellhead, stop injecting high pressure gas, the high pressure gas is nitrogen; the gas flow rate in the oil well is not less than 15.24 m / s.
  • a method for dredging pores of a high pressure gas in an oil well comprises: after the liquid level in the oil well reaches the lower boundary of the reservoir, instantaneously injecting high pressure gas to the bottom of the oil well to accelerate the liquid in the oil well and output it from the wellhead.
  • the method of instantaneously injecting high-pressure gas is to set the time from when the high-pressure gas is injected to when the liquid starts to flow out of the wellhead is the liquid output time, and the duration of the high-pressure gas injection into the oil well is the liquid. 0.7 times the output time.
  • a method for dredging a reservoir of high-pressure gas in an oil well includes: closing the inside of an oil well's wellhead, injecting high-pressure gas into the oil well, pressing the liquid in the oil well back into the reservoir, and then opening the wellhead to release the well. High-pressure gas.
  • the high-pressure gas pushes the liquid in the reservoir in the opposite direction.
  • the pressure of the high-pressure gas in the oil well reaches the highest value, the high-pressure gas in the well is quickly released, so that The liquid and various pollutants in the reservoir are ejected out of the wellhead with the gas; the high pressure gas is repeatedly injected and released into the oil well in a pulsed manner.
  • the beneficial effect of the present invention is that the gas jet oil recovery method can replace mechanical liquid recovery without the need to maintain a dynamic liquid level in the oil well.
  • the gap-type high-pressure gas jet can keep the reservoir in the oil well with good porosity and permeability. After the oil production is completed, a low-pressure cavity without liquid is formed in the oil well, so that the liquid mixed with oil and water can enter the oil well more smoothly, which can greatly increase the flow rate of the liquid in the reservoir into the well and significantly improve the efficiency of oil production; high-pressure gas injection It can avoid the occurrence of bottomhole sediments and significantly improve the maintainability of oil wells; high-pressure gas jet oil recovery also provides technical conditions for the collection of combustible gas in oil wells; gas jet dredging methods can efficiently complete bottomhole dredging and significantly improve The dredging effect can dredge the pores between the oil well and the reservoir, and dredge the pores of the reservoir geology in a large area, which can significantly improve the efficiency of the liquid in the oil reservoir's
  • FIG. 1 is a system diagram of a high-pressure gas stamping device for an oil well according to the present invention
  • FIG. 2 is a schematic diagram of an oil well structure according to the present invention.
  • salvage tool 1 pulse pressure controller 2, downhole drilling tool 3, wellhead 4, drill pipe 5 (i.e. jet pipe), jet pipe joint 6, high pressure pipe 7, tee 8, high pressure pump truck 9 , Control valve 10, accumulator 11, energy storage check valve 12, wellhead tee 13 (that is, the wellhead casing outlet connected to the collector), collector 14, gas detector 15, automatic ignition device 16, air pressure Machine 17, overhaul vehicle 18, safety valve 19, screw conveyor 20, platform 21, rotary self-sealing device 22, wellhead blowout preventer 23 and exhaust pipe 24, high-pressure water pipe 25, oil well 30, oil reservoir 31, Oil 32. Water 33 entering the oil well.
  • L is the bottom depth of the oil well
  • L1 is the height from the liquid surface to the bottom of the well when the liquid surface is in static equilibrium
  • L2 is the height of the lower boundary of the reservoir.
  • an oil well high-pressure gas stamping device includes an energy storage tank 11, a gas injection pipe 5, and a collector 14.
  • the energy storage tank 11 includes a plurality of connected high-pressure gas tanks.
  • the pressure and capacity of the energy storage tank should meet the oil production and maintenance needs of the oil well.
  • the design pressure of the energy storage tank is 35 MPa, and the capacity of the energy storage tank is 20 cubic meters.
  • the high-pressure gas in the energy storage tank is compressed air or nitrogen.
  • the energy storage tank is provided with a safety valve 19.
  • the gas injection pipe is an oil pipe extending into the oil well 30, and the inner hole of the oil pipe serves as a passage for high-pressure gas.
  • the collector 14 is a fully enclosed large tank with a function of automatically separating gas, water, and oil.
  • the lower end of the gas injection pipe (tubing) 5 is connected to the downhole drilling tool 3.
  • the lower end of the downhole drilling tool 3 is installed with a pulse pressure controller 2.
  • the pulse pressure controller is a check valve that opens when the set pressure is reached.
  • the lower end of the pulse pressure controller is connected.
  • a fishing tool 1 with a perforation is provided with a conventional drilling tool, a wellhead blowout preventer 23, a wellhead big cross 13 and a rotary self-sealing device 22 on the wellhead 4 in this order; the oil pipe 5 protrudes upward and the upper end of the oil pipe 5 passes through
  • the gas injection pipe joint 6 is connected to a high-pressure pipe 7.
  • the oil pipe 5 is pulled up by the overhaul vehicle 18 and protrudes from the platform 21 of the oil well.
  • the high-pressure pipe 7 is connected to the tee 8, and one end of the tee 8 is connected to the high-pressure pump truck 9 through a high-pressure water pipe 25.
  • the high-pressure pop-up is responsible for supplying high-pressure water.
  • the other end of the tee 8 is connected to a pressure sensing control valve 10.
  • the control valve 10 is connected to an accumulator 11 and is responsible for gas supply.
  • An energy storage check valve 12 is also provided between the control valve 10 and the tee 8. .
  • the accumulator 11 is provided with a safety valve 19.
  • the wellhead big cross 13 is used as an interface between the wellhead and the collector 14.
  • the wellhead big cross 13 is connected to the collector 14 through a water hose 26 to prevent the gas, water, oil, and sand returned from the well from contaminating the ground environment.
  • a gas detector 15 and an auto-ignition device 16 for detecting methane and hydrogen sulfide are provided on the exhaust pipe 24 of the device 14. When toxic or flammable and explosive gases exceed the standard, it can automatically ignite to eliminate its hazards and ensure normal construction. Perform; the accumulator 11 is connected to the air compressor 17, the air compressor pressurizes the gas in the accumulator 11 so that it reaches a set pressure.
  • the collector 14 is provided with a screw conveyor 20 for discharging solid materials.
  • the pulse pressure controller 2 is a device with a full mechanical structure, without electrical components and a power source, and is used to control the pressure of the high-pressure gas input to the bottom of the oil well. Because the depth of an oil well is usually more than 1 km, and the diameter is usually not more than 200 mm. Due to the long-distance high-speed transmission, it is difficult to control the actual pressure of high-pressure gas input into the well from the ground, and electrical appliances are not allowed in the oil well. Equipment and cables (electrical components may cause flammable gas explosions in oil wells), so the pulse pressure controller without electrical components and power supply can effectively control the actual pressure of the high-pressure gas input into the well (lower limit value of control pressure) .
  • a 7-inch production casing is produced by an oil well, the bottom depth L of the oil well is 1500 m, and the internal volume of the oil well is about 160 cubic meters; in the state of liquid surface equilibrium, the liquid surface reaches the bottom of the well.
  • the height L1 is 400 m (the liquid level equilibrium state is the liquid level in an oil well in a natural state. Due to the formation pressure, the liquid level is usually higher than the upper boundary of the reservoir 31 when the liquid level is in static equilibrium.)
  • the liquid in an oil well mainly includes petroleum, water, and gas. In order to facilitate calculation and obtain safer parameters, the density of water is used as the density of the liquid in the oil well.
  • the pressure of the high-pressure gas input to the bottom of the oil well must not be lower than 4.0 MPa (gas lift pressure during gas lift oil recovery)
  • High-pressure gas includes high-pressure air and high-pressure nitrogen.
  • the high-pressure air is compressed by the air compressor into the energy storage tank.
  • High pressure nitrogen can come from a nitrogen generator and pressurized by an air compressor, or from a high pressure nitrogen bottle.
  • An oil well high-pressure gas stamping oil recovery method is an oil recovery method of the oil well high-pressure gas stamping device according to the first embodiment.
  • the process includes:
  • High-pressure gas is injected into the oil well to drive the liquid in the oil well to be ejected from the outlet of the wellhead casing, and the liquid is collected in a collector and separated in the collector.
  • the high-pressure gas is nitrogen stored in an energy storage tank.
  • the source of nitrogen gas comes from a nitrogen generator.
  • the specific operation is: turning on the air compressor to pressurize the energy storage tank.
  • the calculation method of the pressure in the energy storage tank is: First, according to the pressure of the high-pressure gas is not less than twice the internal pressure of the well bottom liquid, according to the calculation in the first embodiment, the internal pressure of the well bottom liquid is 4.0 MPa (level balance The highest value in the state), the pressure of the high-pressure gas should not be less than 8MPa.
  • the volume of the energy storage tank is 20 cubic meters.
  • the gas in the energy storage tank can store 1,600 cubic meters of nitrogen at normal pressure under the pressure of 8 MPa.
  • the control valve opens, and the high-pressure gas is forced to open the pulse pressure controller through the inner channel of the oil pipe.
  • the liquid inside is ejected from the wellhead and enters the collector. If the oil well contains flammable gas, the high pressure gas drives the flammable gas in the oil well to be ejected from the wellhead with the liquid and enters the collector. When all the liquid in the oil well has been ejected (or there will be no more liquid in the gas stream ejected from the wellhead), stop injecting high pressure gas into the oil well.
  • the liquid in the oil well is collected in a collector and separated in the collector.
  • step b When the liquid level in the oil well rises to the lower boundary of the reservoir (as shown by L2 in Figure 2), high pressure gas is injected into the oil well again to drive the liquid in the oil well to eject from the wellhead, enter the collector, and repeat in sequence. cycle. After step a, the liquid in the oil well is output. Under the effect of formation pressure and other factors, the liquid in the reservoir 31 will continue to seep into the oil well, so that the liquid level in the oil well will gradually rise, as shown in FIG. 2. The rate of liquid seepage into the oil well from the reservoir gradually slows down.
  • the interval between gas injection and oil recovery will be increased, and the liquid column will be suppressed.
  • the oil feed rate reduces the efficiency of oil recovery. If high pressure gas injection is performed when the liquid level in the oil well is low, the oil production of a single high pressure gas injection will be reduced, excessive high pressure gas resources will be consumed, and the cost of oil production will increase. According to engineering practice and research, when the liquid level in the oil well rises to the lower boundary of the reservoir, high-pressure gas jet oil recovery is performed again, which has higher oil recovery efficiency and lower oil recovery cost, which is a better technical solution.
  • the liquid collected in step a and step b is a mixed liquid of oil and water containing grit, and petroleum, water, grit, and combustible gas are precipitated and separated in a collector.
  • Typical equipment for mechanical fluid extraction includes hoe, deep well pump, and downhole structural rod pump.
  • the principle is that the liquid is discharged from the well out of the well through the under-balanced means in the well through the lifting function of the liquid by the machine.
  • the underbalance in the well means that the liquid pressure in the oil well is in a state of equilibrium with the liquid pressure in the formation surrounding the oil well, so that liquid flows between the oil well and the formation, especially the liquid pressure in the reservoir is greater than the liquid in the oil well. Under pressure, the liquid seeps from the reservoir to the well.
  • This process is also known as a “passive” mining process, because it needs to rely on the natural pressure in the reservoir and the ability to maintain fluid balance in the well to generate flow.
  • a dynamic fluid level in the well that is under-balanced in the well is maintained. The liquid in the oil layer flows into the oil well.
  • any liquid has a cumulative pressure (also known as the natural pressure of the liquid). Different depths in the liquid have different cumulative pressures, and the value is the product of the density and depth of the liquid. If they are both liquids (such as oil and water) and have different specific gravity, the total pressure should be calculated in layers. The distribution is in accordance with the law of light up and down.
  • the premise of using mechanical fluid recovery is that a certain height of liquid column must be kept in the well.
  • the determination of the production flow is based on 1 the dynamic liquid level must ensure that the pump body is submerged in it; 2 the natural sedimentation speed of solids such as sand production in the reservoir must be offset in the pumping flow velocity to ensure that sandstone cannot enter the pump barrel to prevent it from occurring Pump accident.
  • the optimal liquid collection parameter determines the dynamic liquid level height (called the optimal liquid collection parameter). Because the height of the liquid column is calculated from the upper boundary of the oil reservoir as the starting point, when oil and water are co-produced in the well, the water is at the bottom and the oil is at the top.
  • coal seam gas net mining project affects the production safety of a large number of coal mines and the comprehensive utilization of coal seam gas. There is an urgent need for a process capable of net mining to release this part of production capacity as soon as possible.
  • the present invention combines basic theory with the current “passive” mining method of mechanical energy, and changes it into a “negative pressure vacuum” of aerodynamic energy. Intelligent integration of "passive” and “active” mining dredging and deblocking.
  • the mechanical energy is converted into aerodynamic energy (performed on the ground), and the energy is stored in a compressed high-pressure gas in an energy storage tank.
  • Gas has the characteristics of compressibility, throughput, energy storage, rapid use, no accumulated pressure, and explosiveness.
  • the gas flow rate can be more than one thousand times the liquid flow rate, and the density of the gas is liquid. (Clear water) 1/800, when the same power as the liquid, the amount of occurrence is 10 times the liquid.
  • the gas velocity reaches 15.24 meters per second, it can carry solid sandstone. Vacuum can be generated during gas lift and liquid movement (difference in gas-liquid density when gas lift generates flow rate).
  • the strength of the vacuum is proportional to air pressure, flow rate, and flow rate (not limited by depth). It can generate resonance during pulses, and the reaction force can be ignored. Excluded (under gas under-equilibrium conditions).
  • the permeability of air permeation is one hundred times that of liquids, and the penetrability is strong, while liquids are incompressible and accumulate energy, have a cumulative pressure, and liquids cannot burst.
  • the gas injection oil production method of the oil well in this embodiment no longer needs to maintain a dynamic liquid level in the oil well, nor does it need a mechanical pump, and there is no risk of failure of the mechanical pump when the dynamic liquid level is exposed.
  • the situation of water-suppressed oil and gas has been completely changed.
  • the production volume can reach tens of thousands of cubic meters.
  • the effect of desilting and plugging can be produced, and the liquid in the reservoir layer can be smoothly flowed into the oil well, and the oil and gas can be produced at the maximum speed and flow rate.
  • a high-pressure gas punching and dredging method for oil wells is the dredging method of the oil well high-pressure gas stamping device according to the first embodiment, and the process includes:
  • High-pressure gas is sprayed to the bottom of the oil well to drive the liquid in the well from the wellhead; then water is added to the high-pressure gas, and the volume fraction of the high-pressure gas to water is 7: 3; water-containing high-pressure gas is sprayed to the bottom of the oil well.
  • the water horsepower is used to drive mud and sand in the oil well from the wellhead casing. After no mud or sand is seen in the gas stream ejected from the wellhead, stop injecting high-pressure gas, which is nitrogen; the gas flow rate in the oil well is not less than 15.24 m / s.
  • the operation method is: firstly spray high-pressure gas to the bottom of the oil well to drive the liquid in the oil well from the wellhead; the oil well high-pressure gas punching method described in the second embodiment can be used After the above operations are completed, the gas pressure in the oil well is under gas equilibrium.
  • the high-pressure pump truck starts water supply, and the ratio of the volume fraction of high-pressure nitrogen to water is 7: 3, that is, the ratio of the volume of compressed high-pressure air to the volume of water is 7: 3.
  • Water and high-pressure gas are mixed and injected into the inner hole of the oil pipe (ie, gas jet pipe), and the high-pressure gas containing water is sprayed into the bottom of the well through the inner hole channel of the oil pipe to dredge the well.
  • the water in the high-pressure gas can strengthen the impulse and the flow rate of the water-containing gas. No less than 15.24 m / s, which can generate water horsepower for mud and liquid downhole.
  • the volume of solid and liquid in the oil well is less than 30% of the volume of gas.
  • the gas-water mixture injected during the upward movement is discharged out of the well in a gasified form.
  • the pressure of the high-pressure gas injected into the oil well should not be less than twice the internal pressure of the bottom fluid in the oil well.
  • the internal pressure of the bottom fluid in the oil well is 4.0 MPa. High pressure gas of MPa for dredging will get better results.
  • Embodiment 4 is a diagrammatic representation of Embodiment 4:
  • a method for dredging pores of oil well high pressure gas punching This embodiment is the pore dredging method of the oil well high pressure gas punching device according to the first embodiment.
  • the method is used for dredging percolation pores between an oil well and a reservoir.
  • the process includes:
  • the high-pressure gas is instantaneously injected into the bottom of the oil well, so that the liquid in the oil well gains acceleration and is output from the wellhead.
  • the method for instantaneously injecting high-pressure gas is to set the time from when the high-pressure gas is injected to when the liquid begins to flow out of the wellhead is the liquid output time, and the duration of the high-pressure gas injection into the oil well is 0.7 times the liquid output time. That is, the expansion force of the liquid released by the high-pressure gas and the motion inertia of the liquid move upwards within 30% of the later period.
  • the liquid in the reservoir will seep into the well.
  • the high pressure gas is instantaneously injected again to the bottom of the oil well, so that the liquid in the oil well is ejected from the wellhead, and this step is repeated several times until the downhole dredging is completed.
  • a good dredging effect can be obtained by performing 5 to 10 high-pressure gas injection processes.
  • the high-pressure gas drives the liquid in the oil well to move toward the wellhead with high acceleration, and the liquid with high acceleration can move upward in the overall form, and is finally discharged from the wellhead.
  • the liquid in the oil well will continue to move upwards with inertia, which can cause a "liquid piston” effect, which causes a vacuum effect at the bottom of the well, that is, the pressure in the oil well is greatly increased.
  • the liquid in the reservoir will get a greater driving suction force into the oil well, and the mud leaking into the reservoir during drilling and the fines in the reservoir close to the well will be fine.
  • the sediment of sandstone has a flushing effect, the mud and sediment will be removed, and the seepage pores between the oil well and the reservoir will be cleared.
  • This method is based on the principle that when the liquid column generated by the lower boundary of the reservoir in the well passes a rapid gas lift, the liquid column can be quickly raised from the bottom of the well to the wellhead.
  • the difference in liquid density is 800 times that of gas and gas can be generated.
  • the characteristics of explosive force and the density of gas are the characteristics of liquid 1/800, which can make the liquid column form a piston function and form a vacuum suction phenomenon. Due to the low gas density and the feature of no cumulative pressure, solid sandstone and liquids downhole can enter the well.
  • the gas lift pressure at the lower part of the liquid column in the well will cause negative pressure.
  • the air supply valve is closed to stop the gas supply, and the liquid column inertia force is exerted to the extreme.
  • Embodiment 5 is a diagrammatic representation of Embodiment 5:
  • a method for dredging an oil well high-pressure gas punching reservoir This embodiment is a method for dredging an oil reservoir of an oil well high-pressure gas punching device according to the first embodiment.
  • the inside of the well head is closed.
  • high-pressure gas is injected into the oil well, so that the liquid inside and outside the oil well is pressed back into the reservoir, and some high-pressure gas is also pressed into the reservoir, and then the wellhead is quickly opened to release the high-pressure gas in the well.
  • the gas in the reservoir is discharged into the oil well with the liquid and water-sensitive mud cake, and this step is repeated multiple times.
  • Each high-pressure gas pulse can increase the pore throat in the original pore foundation in the reservoir, and can unblock formation pores in a larger range of reservoirs.
  • the bottom of the well can be dredged by the high-pressure gas punching and dredging method of the oil well described in Embodiment 3, or the method of Embodiment 2 is used for oil production, and the bottom of the well can be cleaned during the oil production process.
  • a higher pressure is required in this process, and the pressure of the high-pressure gas should be kept not less than 30 MPa.
  • the high-pressure gas is brought to the upper limit of the design pressure of the energy storage tank of 35 MPa.
  • the principle of this method is to increase the pore throat and permeability coefficient in the reservoir by using the characteristics of gas compressibility, explosion, and swallowability.
  • the internal pressure of the liquid is proportional to the specific gravity of the liquid and the depth of the liquid.
  • the increase of the pumping flow can only improve the carrying capacity of the fluid, and cannot cause the fluid to spray upwards in the liquid at a long distance. Only the fluid can be ejected in the gas environment. At this time, the effect of higher flow velocity and longer spray distance will appear. The following situations occur in the traditional process of sand blasting and dredging:
  • Embodiments 3, 4 and 5 can not only solve the long-distance sand card, but also avoid the sleeve milling process. As long as it is not a hard card, it will also avoid all the operating processes of salvage because of the sand card. Makes the workover process very easy. On this basis, vacuum suction is generated without moving any pipe string and tools, which has a good effect on dredging outside the oil well and unblocking the target layer.
  • the invention can clear the silt and plug the underground pipe string of all oil, water and gas wells, and remove the stuck cards. It can simultaneously perform high-speed jet impact cleaning in the well, and simultaneously vacuum the pollution outside the oil well while fishing at one time.
  • It is the most powerful, direct, easiest and most economical best oil recovery assisted process for solving dredging and plugging outside oil wells.
  • I. Use high-pressure energy storage gas concentration speed to inject nitrogen into the well to make a gas lift liquid column to return the liquid up to the well.
  • a high-pressure pump truck is forcibly injected into the gas pipeline into the well.
  • Fresh water uses water to generate water horsepower, and in the case of gas in the well, a jet stream is generated to impact the mud at the bottom of the well.
  • the workover project can also achieve this goal.
  • the wellhead passage is blocked, a large amount of gas is injected into the well through the reservoir borehole, and the reservoir is transformed by pulse resonance.
  • the physical properties of the layer increase the pore throat, and the wellhead is discharged at regular intervals to flush various pollutants.
  • This solution can not only maintain liquid column hedging in the reservoir section of the reservoir, but also can accelerate the fluid inflow rate without producing water to suppress oil and gas production.
  • this solution can continuously store energy, guarantee that the equipment works with low power, and intermittently accumulates the liquid column in the downhole to recover oil. It can also achieve the intermittent oil recovery at the same time as the process of desilting and plugging is synchronized.
  • gas oil production can make the lower boundary of the oil reservoir in the well without the need to retain the liquid column, and there is no mechanical pump in the well, so the reservoir can be completely exposed and produced under the accumulated pressure without liquid. Because of the difference in the specific gravity of water, oil, and gas, gas will enter the well first.
  • a vacuum pump can be installed at the wellhead to evacuate the gas to the wellhead container and then compress it. Fill the container and store it for use.
  • the concentration of natural gas in the casing ring is already very low, and the remaining gas can reach the emission standard and be discharged to the atmosphere together with the injected high-pressure nitrogen. When the discontinued period is repeated, draw.
  • the purity of natural gas in the well can reach the emission standard, and it can be fully utilized for co-production of oil and gas.
  • the oil and gas in the well are often twin sisters. When there is oil, gas is produced. However, the pressure of the gas causes the accumulated pressure in the liquid column retained in the well to be suppressed by mechanical oil production. There is no chance to release it.

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Abstract

一种油井（30）高压气体冲压装置及方法；装置包括储能罐（11）、喷气管（5）和收集器（14），喷气管（5）从油井（30）的井口（4）伸入油井（30），储能罐（11）中存储高压气体，喷气管（5）通过管道（7）连接储能罐（11），收集器（14）是收集油井（30）内液体的收集器（14）。方法包括油井（30）高压气体冲压采油方法、油井（30）高压气体冲压清淤方法、油井（30）高压气体冲压孔隙疏通方法及油井（30）高压气体冲压储油层疏通方法。

Description

一种油井高压气体冲压装置及方法 技术领域
本发明属于采油工程技术，尤其涉及一种油井高压气体冲压装置及方法。
背景技术
目前的采油技术除自喷井外，95％都是利用机械能直接转化液体动能的开采工艺开采石油或混合有石油的液体，称为“机械液采”，储油层中的液体依靠井内欠平衡自然流动方式进入井内，保持与开采流量的平衡。因而此种工艺也被称为“被动式”开采工艺。典型的装置是采用抽油泵将油井内液体输送到地面。
机械采液的共同特性是井内必须保留一定高度的液柱淹没泵体，否则会发生严重的机械事故，即抽油泵必须在动态液面以下。因此开采流量的确定是根据动态液面高度确定的，必需保证把泵体淹没其中。在开采过程中，要避免储油层出砂等固体物进入泵筒，以防止发生卡泵事故，要使砂砾等固体物沉降到井底，所以抽取速度不能大于井内储油层出砂的沉降速度，才会在井底积累沉积物。沉积到一定程度就会影响正常的采油工作，需要进行对油井进行清淤，也会影响油井的采油工作。它也代表典型的传统工艺。
井内的动液面直接影响油井产量的重要因素，动态液面高度越小,储油层中的液体进入井内的流量就越大、油井产量越高，并且呈几何倍数增高。由于机械采液必须保持足够高度的动态液面，因此极大地限制了油井的开采量，通常可采储量比探明储量小60％，这是机械采液的最大痛点。而且，在此技术背景下，采出的油往往达不到采液量的1％。
因为动态液面的高度要高于储油层，当井内是油水同层共同开采时，由于水的比重大于油，水会压储油层中的油，油不能与水一样的速度进入井内(即油井的生产套管内)，也会明显影响储油层中的液体进入井内的流量。即产生水追现象。
油田进入中后期开采阶段后，经常采取压裂工艺、酸化、化学解堵、工艺注水、注聚、三元驱油工艺等措施，注水注聚会造成油水同层、底水大增、水串水锥后果严重，储油层中泥岩膨胀高发，导致孔隙度、渗透率严重变差，这也是各油田普遍存在的实际情况。
在修井工程中，油田进入中后期开采阶段，井下解卡、清淤、解堵、套变、挫断、套铣、打捞、砂埋等工作量大增，主要原因如之前所述，传统工艺的压裂、酸化、边水串层导致的水敏发生泥岩膨胀出现的应力释放等，使套管损坏，导致取套工作量大增，并且现有修井工艺没有超越传统工艺基础，导致大批待修井等待修复及复产，也在影响产能。修井工艺的落后，使修井周期延长，成本大幅度上升。
对于一些非常规能源。如煤层气、产油井当中伴生气、页岩气是非常贵能源，但无法采用机械采液方式进行开采，也是一项有待解决的技术问题。特别是储油层当中的伴生气，因为密度更小，始终被井内所产生的液柱所产生自然压强所压制，得不到释放机会。
发明内容
本发明的目的是提出一种油井高压气体冲压装置及方法的技术方案，提高油井的开采率和开采效率，充分发掘油井的开采资源。
为了实现上述目的，本发明的技术方案是：一种油井高压气体冲压装置；所述装置包括储能罐、喷气管和收集器，所述喷气管从所述油井的井口伸入油井，所述储能罐中存储高压气体，所述喷气管通过管道连接所述储能罐，所述收集器是收集所述油井内液体的收集器，所述收集器连通所述油井的井口。
更进一步，为了更好地控制喷入油井内的高压气体的压力，所述喷气管伸入到所述油井的井底，所述喷气管的前端设有达到设定压力时开启的脉冲压力控制器，所述收集器连通所述油井的井口套管出口，所述喷气管通过三通连接输入高压水的高压水管。
更进一步，一种较佳的装置配置是，所述储能罐内不小于20立方米，所述储能罐内的气体压力为35MPa。
一种油井高压气体冲压采油方法；所述方法包括：
a.向油井内喷射高压气体，驱使所述油井内液体从井口套管出口喷出，所述液体被收集在收集器中、并在收集器中进行分离；
b.当油井内液体的液面高度上升到储油层下界时，再次向油井内喷射高压气体，驱使所述油井内液体从井口套管出口喷出，并依次重复循环；
更进一步，为了获得更好的采油效果和效率，从所述油井井底向油井内喷射高压气体，所述高压气体的压力不小于油井井底液体内部压强的2倍，所述高压气体是氮气；所述液体在收集器中进行油、水及沉淀物的分离。
一种油井油井高压气体冲压清淤方法；所述方法包括：
向油井井底喷射高压气体，驱使油井内的液体从井口喷出；然后向高压气体中加入水，高压气体与水的体积份数比为7:3；向油井井底喷射含水的高压气体，利用水马力驱使油井内泥砂及液体从井口套管喷出，待井口喷出的气流中未见到泥砂后，停止喷射高压气体，所述高压气体是氮气；所述油井内气体的流速不小于15.24米/秒。
一种油井高压气体冲压孔隙疏通方法；所述方法包括：在油井内液面高度达到储油层下界后，向油井井底瞬时喷射高压气体，使油井内液体获得加速度，并从井口输出。
更进一步，所述瞬时喷射高压气体的方法是，设开始喷射高压气 体的时刻至液体开始从所述井口流出的时刻为液体输出时间，向所述油井内喷射高压气体的持续时间是所述液体输出时间的0.7倍。
一种油井高压气体冲压储油层疏通方法；所述方法包括：使油井井口内处于封闭状态，向油井内注入高压气体，使所述油井内液体被压回到储油层中，然后打开井口释放井内高压气体。
更进一步，为了更好地实现储油层疏通，所述高压气体把储油层中的液体推向相反的方向，当所述油井内的高压气体的压力达到最高值后，快速释放井内高压气体，使储层当中的液体及各种污染物随着气体一起喷出井口；以脉冲方式多次重复向油井内注入和释放高压气体。
本发明的有益效果是：气体喷射采油方法可替代机械采液，不需要在油井内保持动态液面，间隙式的高压气体喷射可以使油井中储油层保持良好的孔隙度和渗透率，一次喷射采油完成后在油井中形成没有液体的低压空腔，使油水混合的液体能够更为顺畅地进入油井，因而可极大提高储油层中的液体进入井内的流量，显著提高采油效率；高压气体喷射可避免产生井底沉积物，显著提高油井的可维护性；高压气体喷射采油还为采集油井中的可燃气提供了技术条件；气体喷射清淤方法可高效率地完成井底清淤，显著提高清淤效果，并可疏通油井与储油层之间的孔隙，及疏通较大范围内储油层地质的孔隙，可明显提高油井的清储油层内的液体进入油井的效率，显著提高油井的产能。
下面结合附图和实施例对本发明进行详细描述。
附图说明
图1是本发明油井高压气体冲压装置***图；
图2是本发明涉及的油井结构示意图。
图中的标号为：打捞工具1、脉冲压力控制器2、下井钻具3、 井口4、钻杆5(即喷气管)、喷气管接头6、高压管道7、三通8、高压泵车9、控制阀门10、蓄能器11、蓄能逆止阀12、井口大四通13(即连接收集器的井口套管出口)、收集器14、气体检测仪15、自动点火装置16、空压机17、大修车18、安全阀19、螺旋输送机20、平台21、旋转自封器22、井口防喷器23和排气管24、高压水管25，油井30、储油层31、进入油井的油32、进入油井的水33。L为油井的井底深度，L1为液面静平衡状态时液面至井底的高度，L2为储油层下界的高度。
具体实施方式
实施例一：
如图1，一种油井高压气体冲压装置，包括储能罐11、喷气管5和收集器14。
储能罐11包括多个连通的高压气罐，储能罐的压力和容量应满足油井的采油和维护需要。本实施例中，储能罐的设计压力为35MPa，储能罐的容量为20立方米。储能罐中的高压气体是压缩空气或氮气。储能罐设有安全阀19。
喷气管是伸入油井30内的油管，油管的内孔作为高压气体的通道。收集器14是全封闭具有自动分离气、水、油功能的大罐体。
喷气管(油管)5的下端连接下井钻具3，下井钻具3的下端安装脉冲压力控制器2，脉冲压力控制器是达到设定压力时开启的单向阀，脉冲压力控制器的下端连接带孔眼的打捞工具1，依次将常规钻具、井口防喷器23、井口大四通13和旋转自封器22设置在井口4上面；油管5向上伸出旋转自封器22、油管5的上端通过喷气管接头6连接高压管道7。油管5被大修车拉动18向上竖起，并伸出油井的平台21。高压管道7连接三通8，三通8的一端通过高压水管25连接高压泵车9，高压蹦出负责供高压水。三通8的另一端连接至 装有压力传感控制阀门10，控制阀门10连接蓄能器11，负责供气，在控制阀门10与三通8之间还设有一个蓄能逆止阀12。蓄能器11上设有安全阀19。
井口大四通13作为连接井口与收集器14的接口，井口大四通13通过水龙带26与收集器14连接，以防止从井内返出的气、水、油、泥砂污染地面环境，在收集器14的排气管24上设有检测甲烷与硫化氢功能的气体检测仪15及自动点火装置16，当有毒气体或易燃易爆气体超标时能自动点火来消除其危害，确保施工能够正常进行；储能器11与空压机17连接，空压机对储能器11中的气体加压，使其达到设定的压力。收集器14设有用于排出固体物料的螺旋输送机20。
脉冲压力控制器2是全机械结构的装置，不带有电器部件和电源，作用是控制输入油井底部的高压气体的压力。由于油井的深度通常可达1千米以上，直径通常不大于200mm，由于存在长距离的高速传输，从地面难以控制输入到井内的高压气体的实际压力，而在油井内有不允许通入电器设备和电缆(电器部件可能引发油井内可燃气体的***)，因而不带有电器部件和电源的脉冲压力控制器能够有效的控制输入到井内的高压气体的实际压力(控制压力的下限值)。
如图2所示，本实施例中，油井采油7寸的生产套管，油井的井底深度L为1500m，油井内容积约为160立方米；在液面静平衡状态时液面至井底的高度L1为400m(液面平衡状态是在自然状态下油井内的液面，由于地层压力，液面静平衡状态时液面通常会高于储油层31的上界)。油井内的液体主要包括石油、水、气，为了方便计算并获得更安全的参数，以水的密度作为油井内液体的密度，故油井井底液体内部压强为400m×1000kg/m 3＝400000kg/m 2≈4.0MPa。为了保证高压气体能够驱动油井内的液体，输入油井底部的高压气体的压力须 不低于4.0MPa(气举采油时的气举压力)
高压气包括高压空气和高压氮气。高压空气由空压机压缩大气输入储能罐。高压氮气可以来自制氮机并经空压机加压，或来自高压氮气瓶。
实施例二：
一种油井高压气体冲压采油方法。本实施例是实施例一所述的油井高压气体冲压装置的采油方法，过程包括：
a.向油井内喷射高压气体，驱使所述油井内液体从井口套管出口喷出，所述液体被收集在收集器中、并在收集器中进行分离。高压气体是存储在储能罐中的氮气，氮气的气源来自制氮机。
结合实施例一所述的油井高压气体冲压装置，具体操作是：开启空压机，对储能罐进行储气增压。储能罐内的压力的计算方法是：首先根据高压气体的压力不小于油井井底液体内部压强的2倍，根据实施例一中的计算，油井井底液体内部压强为4.0MPa(液面平衡状态时的最高值)，高压气体的压力应不小于8MPa。储能罐的容积为20立方米，储能罐内的气体在8MPa压力下可存储常压状态下1600立方米的氮气，为了保证足够的高压气源，储能罐输出的气体量(以常压状态计)应不小于油井内容积的12倍，油井内容积为160立方米，即1920立方米，故储能罐中的空气总量(在常压状态下)1600立方米+1920立方米＝3520立方米，在20立方米储能罐内，在17.6MPa的压力下可存储3520立方米的氮气。在8MPa与17.6MPa之间取压力值较高者，储能罐内的压力值下限为17.6MPa。
当储能罐内的压力值达到下限时控制阀开启，高压气体通过油管内孔通道强制打开脉冲压力控制器，喷入井底，输入油井的高压气体对井内液体产生“气举”功能，驱使油井内的液体从井口喷出，进入收集器。如油井内含有可燃气体，高压气体驱使油井内的可燃气体与 液体一同从井口喷出，进入收集器。当油井内的液体被全部喷出后(或在井口喷出的气流中不再会有液体时)，停止向油井内喷射高压气体。
油井内的液体被收集在收集器中、并在收集器中进行分离。
b.当油井内液体的液面高度上升到储油层下界(如图2中L2)时，再次向油井内喷射高压气体，驱使所述油井内液体从井口喷出，进入收集器，并依次重复循环。经过步骤a后，油井内的液体被输出，在地层压力等因素的作用下，储油层31中的液体会继续向油井内渗流，使油井内的液面逐渐升高，如图2所示。储油层中的液体向油井内渗流的速度是逐渐减缓的，若待油井内液体达到液面平衡高度后再进行高压气体喷射采油，会增加气体喷射采油的间隔时间，也会产生液柱压制对冲进油速度，降低采油效率；若在油井内液面较低时进行高压气体喷射采油，会降低单次高压气体喷射采油的采油量，消耗过多的高压气体资源，增加采油成本。根据工程实践和研究，当油井内液体的液面高度上升到储油层下界时，再次进行高压气体喷射采油，具有较高的采油效率和较低的采油成本，是一个较佳的技术方案。
经步骤a和步骤b采集的液体是含有砂砾的石油与水的混合液体，石油、水、砂砾以及可燃气体在收集器中进行沉淀分离。
目前除自喷井外，95％的油井都是利用机械能直接转化液体动能的开采工艺开采石油和各种液体，装置工艺可称为“机械液采”。机械采液的共同特性是井内必须保留一定高度的液面淹没泵体，否则会发生严重的机械事故。
机械采液的代表性设备包括磕头机，深井泵，井下结构管杆泵。其原理是通过机械对液体的提升功能，利用井内欠平衡手段把液体从井内排出井外。所述井内欠平衡是指油井内的液体压力与油井周围的地层中的液体压力处于平衡状态，使液体在油井和地层之间产生流动，尤其是指在储油层中的液体压力大于油井内液体压力的状态，液体从 储油层向油井内渗流。此种工艺也被称为“被动式”开采工艺，因为需要依靠储油层中的自然压强与井内保持平衡的进液能力来产生流量，在油井中保持一个井内欠平衡状态的动态液面，使储油层中的液体向油井内流动。
根据流体动力学基础理论，凡是液体都存在着累积压强(也称为液体自然压强)，液体中不同深度的位置具有不同的累积压强，其值为液体的密度与深度的乘积。如果同属于液体(如油、水)，不同比重，其总压强应分层计算累积总合，其分布符合轻上重下的规律。
采用机械液采的前题，是井内必须保留一定高度的液柱。开采流量的确定是根据①动态液面高度必需保证把泵体淹没其中；②储油层出砂等固体物自然沉降速度在泵抽排流速当中须被抵消，保证砂岩不能进入泵筒，以防止发生卡泵事故。有了这两点再确定动态液面高度(被称为最佳采液参数)。因为液柱的高度是从储油层上界做为起点计算的，当井内是油水同层共同开采时，水在底部，油在上部。这说明水在储油层射孔段出口处始终压制储油层当中的油不能与水一样的速度进入油井内。虽然油、水都属于液体，但因比重大小而分先后进入井内，重多、轻少是自然规律。因为井内存在动态液面，决定了油井内外压强是平衡状态，并不是油井外压强大，而油井内压强小。该井产液量多少，与井内液柱高度有关，此液柱高度越小产量越高，并且呈几何倍数增高。
单纯追求产液量的提高是误区，关键是确定产水量。如果产水量是日产100吨，把泵的排量提高到200吨，使井内根本产生不了液面，此时射孔段大门全部放开，让油水同场竞技，就不会存在水堵油的现象。水堵油是油井可采储量比探明储量小60％的主要原因。只要使用机械泵采就不可违背原则，必需保留液柱。这就是使用机械泵采的最大痛点。目前各大油田在此技术背景下，采出的油还达不到采液量的 1％。
就油田进入中后期开采阶段储油层状况而言，在开采初期，原始地层自然压强已释放残尽，大部分区块已经进入平衡期。自喷井逐步退出，采油工程受到了极大考验。这时自喷井转机械采油技术大量涌现。电潜泵，因排量可观被大量应用。螺杆泵因出砂比较大而得到应用。抽油机、深井泵使用至今。当开发进入中后期，电潜泵也被逐渐放弃(因产液量减少)，证明油田迈向衰减期。各油田为了延长开采时间，大力开展新区块的开发，钻新井，打加密井、调整井、水平井，采取压裂工艺、酸化、化学解堵、工艺注水、注聚、三元驱油工艺等措施，最终也没有止住掉产的现实，也没有新增可动用的区块，可是却大大增加了采油成本。
在中国，老区块钻加密井都没地方布井，钻水平井成本太高，投入与产出差距太小，导致浅层传统井队大批待业。压裂工艺其实是只见眼前短期效益，牺牲长远利益并可能造成次生灾害。压裂造缝加大流油通道一旦度过初期，比原来效果更差，另外套外水泥环的损坏发生水串导致泥岩发生膨胀现象，这种膨胀应力会造成套管轻则变形，重则挫断。目前该类大修井以每年20％的速度在增长，影响一大批油井不能正常生产。酸化解堵，因为地层吸收量太大，注入量不够而影响面积有限。注水注聚造成油水同层、底水大增、水串水锥后果严重，储油层中泥岩膨胀高发，导致孔隙度、渗透率严重变差，这也是各油田普遍存在的实际情况。
在钻井工程中，为防止各层发生水串，严格要求固井质量，拿固井质量衡量钻井合格率，但是却无法解决油水同层问题。更无法解决利用机械采油时井内人为的保留液柱，当中的水是产生水追最大元凶这一难题。所以改变机械采油方式，是解决开采储层当中的剩余油的当务之急。
大于非常规能源，低压力，高含水，易出砂的代表井，如煤层气、产油井当中伴生气、页岩气等非常贵能源的开采难题在全世界也没有得到彻底的解决，特别是煤层气净采工程，影响大批煤矿的产能建设安全和煤层气的综合利用。急需一种能够净采的工艺尽快释放这部分产能。
本发明根据气体动力学、流体动力学及在人为加以控化形成的特定环境中的工程力学等原理，结合基础理论针对目前机械能“被动”的开采方式，改变为气体动力能“负压真空”清淤解堵智能一体化“被动”加“主动”开采模式。
(一)气体动力能特点：
首先利用机械能转化成气体动力能(在地面上进行)，将能量存储在储能罐中被压缩的高压气体。气体具有可压缩、可吞吐、可储能、可急速使用、不存在累积压强、并且可爆发等特点，在相同能量的驱动下，气体流速可大于液体流速的一千倍，气体的密度是液体(清水)的1/800，在与液体同功率情况时发生量是液体10倍。在气体流速达到每秒15.24米时，可携带固体砂岩。在气举液动时可以产生(气举产生流速时气液密度差)真空，真空的强度与气压、流量、流速成正比(不受深度限制)，可在脉冲时产生共振，反作用力可以忽略不计(在气体欠平衡条件下)。气透的渗透率是液体的百倍，穿透性强，而液体是不可压缩和蓄积能量的，具有累积压强，液体不可吞吐爆发的。
根据上述基础理论，经过控化可以突破负压真空抽吸解堵、无泵混采、一体化同采、地面多项分离处理工艺进行采油采气。
本实施例的油井气体喷射采油方法，不再需要油井内保持一个动态液面，更不需要机械泵，也不会出现机械泵露出动态液面发生故障的的风险。彻底改变了水压制油气的情况，采出量根据设计，最高可 达上万立方。同时在采油过程中，可产生清淤解堵的效果，保持储油层中液体渗流到油井中的畅通，以最大的速度和流量，开采油、气。
实施例三：
一种油井高压气体冲压清淤方法。本实施例是实施例一所述的油井高压气体冲压装置的清淤方法，过程包括：
向油井井底喷射高压气体，驱使油井内的液体从井口喷出；然后向高压气体中加入水，高压气体与水的体积份数比为7:3；向油井井底喷射含水的高压气体，利用水马力驱使油井内泥砂及液体从井口套管喷出，待井口喷出的气流中未见到泥砂后，停止喷射高压气体，所述高压气体是氮气；所述油井内气体的流速不小于15.24米/秒。
结合实施例一所述的油井高压气体冲压装置，操作方法是：首先向油井井底喷射高压气体，驱使油井内的液体从井口喷出；可采用实施例二所述的油井高压气体冲压采油方法完成上述操作，油井内气压处于气体欠平衡状态。
然后高压泵车启动供水，高压氮气与水的体积份数比为7：3，即被压缩的高压空气的体积与水的体积之比为7：3。
水与高压气体混合同时注入油管内孔(即喷气管)，通过油管内孔通道使含水高压气体喷入井底，对井下进行清淤，高压气体中的水份能够加强冲力，含水的气体的流速不小于15.24米/秒，可使井下泥砂及液体产生水马力，油井内固、液两项体积小于气体体积30％，在向上运动程中注入的气水混合物以气化的形式排出井外。
通常情况下，油井井底液体内部压强越大，井底的淤积物就越密实，需要更高压力的气体进行清除。为了保证清淤效果，根据经验，喷入油井内的高压气体的压力应不小于油井井底液体内部压强的2倍，如实施例一所述，油井井底液体内部压强为4.0MPa，采用8.0MPa的高压气体进行清淤会获得较好效果。
因为井下可能存在甲烷等可燃气体，高压空气中含有氧气，井内的砂岩在高速运动时与井壁钢管产生摩擦就会产生静电火花，此时着火***三个要素都具备。当甲烷浓度超过15.5％时，就可能发生***事故。如果注入氮气代替空气，成本会很高。所以采用科学的手段是在井内注入空气和水生成气化水，即可全面消除静电现象的产生过程，安全问题就得到保障。本方法通常针对机械液采的油井是不能加以应用的。对应采用实施例二所述的油井只能停井，检泵冲砂清淤。
实施例四：
一种油井高压气体冲压孔隙疏通方法，本实施例是实施例一所述的油井高压气体冲压装置的孔隙疏通方法，用于疏通油井与储油层之间的渗流孔隙，过程包括：
在油井内液面高度达到储油层下界后，向油井井底瞬时喷射高压气体，使油井内液体获得加速度，并从井口输出。
所述瞬时喷射高压气体的方法是，设开始喷射高压气体的时刻至液体开始从井口流出的时刻为液体输出时间，向油井内喷射高压气体的持续时间是所述液体输出时间的0.7倍。即液体在后程的30％时间内由高压气体释放的膨胀力和液体自身的运动惯性向上移动。
在一次上述过程完成后，储油层内的液体会向油井内渗流。当油井内液面高度达到储油层下界，再次向油井井底瞬时喷射高压气体，使油井内液体喷出井口，并重复本步骤多次，直至完成井下清淤。根据实践经验，对通常的油井而言，进行5次～10次高压气体喷射过程，即可获得获得良好的清淤效果。
本方法中，高压气体驱使油井内的液体以高加速度向井口运动，高加速度的液体可以整体形态向上运动，最终从井口排出。在这个运动过程中，当停止喷射高压气体后，油井内的液体仍然会以惯性继续向上运动，可造成一个“液体活塞”的效应，使井底产生一种真空效 应，即油井内的压力大大低于油井外储油层的压力，此时储油层中的液体会获得较大的驱动抽吸力进入油井，对钻井时渗漏到储油层里的泥浆、及接近油井的储油层中的粉细砂岩的沉淀物产生冲洗作用，所述泥浆及沉淀物会被清除，油井与储油层之间的渗流孔隙得以疏通。
本方法依据的原理是：当井内储油层下界产生的液柱通过急速气举时，可以使该液柱迅速从井底向井口方向上升，利用液体密度是气体800倍的异差和气体可产生爆发力的特点，及气体的密度是液体1/800的特征，可使液柱形成活塞功能，形成真空抽吸现象。由于气体密度低、也不产生累积压强的特征，所以井下的固体砂岩及液体可以进入井内。当井内液柱出现加速度时(产生了液柱惯性)井内液柱下部的气举压力会出现负压，此时关闭送气阀门，停止送气，让液柱惯性力真空发挥到极致。
实施例五：
一种油井高压气体冲压储油层疏通方法，本实施例是实施例一所述的油井高压气体冲压装置的储油层疏通方法，用于疏通储油层较大范围的渗流孔隙，过程包括：
首先使油井井口内处于封闭状态。然后向油井内注入高压气体，使油井内外液体被压回到储油层中，部分高压气体也被压到储油层中，然后迅速打开井口释放井内高压气体。在储油层内压力的驱使下，油层中的气体带着液体及水敏后的泥饼排入油井，重复本步骤多次。每一次的高压气体脉冲都能够在储层当中原有孔隙基础之产生加大孔喉的作用，可对更大范围的储油层内地层孔隙实现疏通。之后可采用实施例三所述的油井高压气体冲压清淤方法对井底清淤，或采用实施例二的方法进行采油，在采油过程中使井底得到清理。
本过程中需要较高的压力，应保持高压气体的压力不小于30MPa。本实施例中，使高压气体达到储能罐设计压力的上限35MPa。
本方法的原理是利用气体可压缩、可爆发、可吞可吐的特性来加大储层当中的孔喉，及渗透系数
目前国内外油田传统的井下清淤冲洗解卡作业中，通常采用将液体通过泵做功后在井内建立起液流循环，把井内的泥砂返到地面的工艺流程。该工艺存在以下缺陷：
由于液体存在液体累积压强，液体内部压强与液体比重和液体深度成正比。在几千米的井下存在很大的液体内部压强，泵出流量的提高，只能提高流体的携带能力，而不能使流体在液体中产生远距离的向上喷射，只有使流体在气体环境中喷射，这时才会出现流速越高、喷射距离越远的效果。在传统工艺的井下冲砂清淤作业时就会出现以下情况：
在井内落物后发生长距离砂卡的情况下只能采用套铣作业。大直径工具又不能采用套铣作业时，就只能倒扣打捞，分段冲洗。实际工作中如果发生这种情况，后续修井工程的打捞工艺就会非常繁杂，大大增加修井周期，甚至导致油井报废。由于井内液体液体内部压强的存在，平衡了套管外部地层的自然压强，所以传统清淤工艺只能对套管井内起到一定清淤效果，而对于套管外地层中存在的各种污染，如钻井时遗留在油层中的泥浆污染、近井地带粉砂沉积造成的污染及由于注水导致的地层中泥岩遇水膨胀生成的泥饼污染，则不会产生任何作用。油田开发中后期，由于长时间的注水、注酸作业，频繁的井下作业施工以及套管材质与腐蚀、地层的变化等诸多因素，经常会发生套管挫断。套管挫断处发生的套管外塌方可使上、下套管发生移位，套管腐蚀，导致正常采油、作业工具不能顺利通过。如果不把套管外这部分泥砂清理到井外，使用领尖工具也不能扶正套管，套管还容易被破坏。如果此处严重变形，领尖工具也找不到下部套管，只能采用将上部套管取出井外等措施解决。
采用实施例三、实施例四和实施例五的方法，不但可以解决长距离砂卡，也可以免去套铣过程，只要不是硬卡也会免去因为砂卡倒扣打捞的所有作业流程，使修井工艺变得非常轻松。在此基础上不动任何管柱和工具就会产生真空抽吸，对油井外清淤、目的层解堵具有很好的效果。本发明能够对所有油、水、气井的井下管柱严重漏失的清淤解堵及井下解卡作业，既可同时完成高速喷射冲击井内清洗，又具有真空抽吸油井外污染同时一次性打捞的功能。是解决油井外清淤解堵的最有力、最直接、最简便、最经济的终极采油最佳辅助的工艺。
本发明技术方案的特点是：
一.利用高压储能气体集速集中向井内注入氮气，做气举液柱使液体上返出井内，当井内达到气体欠平衡的瞬间，向输气管路内通过高压泵车，向井内强行注入清水，利用水产生水马力，在井内气体情况下产生喷射流冲击井底泥砂，气水流量、流速只要达到15.24米/秒以上，即可完成清淤任务。(修井工程同样可以达到此目地)。
二.利用气体渗透率是液体渗透率一千倍和可压缩、可爆发、可吞吐的特性，把井口通道堵死，向井内通过储油层炮眼注入大量的气体，并以脉冲共振手段，改造储层物性加大孔喉，定量定时开放井口返排，冲洗各种污染物。
三.利用急量气体气压举升储油层下界所积累的液柱产生的抽吸真空现象，通过射孔段，对储层产生强力抽吸采油，由负压被动采油，改为主动采油，同时排渣清淤于一体。原理是液体的密度是气体的800倍，液柱通过高压气举后可产生使液柱逐步出现加速度状态，即液柱会产生活塞作用，当液柱出现加速时，井内气体压力马上会降低到负压显示，此时关闭送气阀门，使真空度保持最大。此方案既能保持储油层井段无液柱对冲，井外进液速度还能加速进液量，也不产生水追压制油气产量。为了节省用气量，此方案可以连续储能，保障设 备以小功率做工，间断累积井下液柱的方式采油，并且可以做到每次间断采油的同时，也是清淤解堵过程在同步进行。
四.利用气体采油，可使井内储油层下界以无需保留液柱，井内也无机械泵，所以储油层可以全部裸露在无液体产生的累积压强下生产。因为水、油、气比重的差异，气会最先进入井内，可以在间断采油时利用井口安装一台真空泵先把气体抽排到井口容器中再压缩，充入容器中储存在利用。当采油真空时，套管环空中的天然气浓度已经很低，所剩余的气体可以达到排放标准，与所注的大量高压氮气一起排放到大气层。当间断时段再进行，抽排。即可达到，井内天然气的纯度又可达到排放标准，又可以油气同采充份利用。井内油气往往是一对孪生姐妹，有油就产生气，只不过气体的压力，让机械采油时井内所保留液柱产生累积压强给压制住了，没有机会得到释放。

Claims (10)

  1. 一种油井高压气体冲压装置；其特征在于，所述装置包括储能罐、喷气管和收集器，所述喷气管从所述油井的井口伸入油井，所述储能罐中存储高压气体，所述喷气管通过管道连接所述储能罐，所述收集器是收集所述油井内液体的收集器，所述收集器连通所述油井的井口。
  2. 根据权利要求1所述的一种油井高压气体冲压装置，其特征在于，所述喷气管伸入到所述油井的井底，所述喷气管的前端设有达到设定压力时开启的脉冲压力控制器，所述收集器连通所述油井的井口套管出口，所述喷气管通过三通连接输入高压水的高压水管。
  3. 根据权利要求1所述的一种油井高压气体冲压装置，其特征在于，所述储能罐内不小于20立方米，所述储能罐内的气体压力为35MPa。
  4. 一种油井高压气体冲压采油方法；其特征在于，所述方法包括：
    a.向油井内喷射高压气体，驱使所述油井内液体从井口套管出口喷出，所述液体被收集在收集器中、并在收集器中进行分离；
    b.当油井内液体的液面高度上升到储油层下界时，再次向油井内喷射高压气体，驱使所述油井内液体从井口套管出口喷出，并依次重复循环；
  5. 根据权利要求4所述的一种油井高压气体冲压采油方法，其特征在于，从所述油井井底向油井内喷射高压气体，所述高压气体的压力不小于油井井底液体内部压强的2倍，所述高压气体是氮气；所述液体在收集器中进行油、水及沉淀物的分离。
  6. 一种油井油井高压气体冲压清淤方法；其特征在于，所述方 法包括：
    向油井井底喷射高压气体，驱使油井内的液体从井口喷出；然后向高压气体中加入水，高压气体与水的体积份数比为7:3；向油井井底喷射含水的高压气体，利用水马力驱使油井内泥砂及液体从井口套管喷出，待井口喷出的气流中未见到泥砂后，停止喷射高压气体，所述高压气体是氮气；所述油井内气体的流速不小于15.24米/秒。
  7. 一种油井高压气体冲压孔隙疏通方法；其特征在于，所述方法包括：在油井内液面高度达到储油层下界后，向油井井底瞬时喷射高压气体，使油井内液体获得加速度，并从井口输出。
  8. 根据权利要求7所述的一种油井高压气体冲压孔隙疏通方法，其特征在于，所述瞬时喷射高压气体的方法是，设开始喷射高压气体的时刻至液体开始从所述井口流出的时刻为液体输出时间，向所述油井内喷射高压气体的持续时间是所述液体输出时间的0.7倍。
  9. 一种油井高压气体冲压储油层疏通方法；其特征在于，所述方法包括：使油井井口内处于封闭状态，向油井内注入高压气体，使所述油井内液体被压回到储油层中，然后打开井口释放井内高压气体。
  10. 根据权利要求9所述的一种油井高压气体冲压储油层疏通方法，其特征在于，所述高压气体把储油层中的液体推向相反的方向，当所述油井内的高压气体的压力达到最高值后，快速释放井内高压气体，使储层当中的液体及各种污染物随着气体一起喷出井口；以脉冲方式多次重复向油井内注入和释放高压气体。
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