Method for improving recovery ratio of thickened oil steam channeling well

Abstract

The invention provides a method for improving the recovery ratio of a thickened oil steam channeling well. The method comprises the following steps: step 1, determining a heavy oil reservoir production well which is subjected to steam flooding and / or steam huff and puff and has a steam channeling channel as a target well; 2, mixed gas of high-temperature steam and air is injected into a target well stratum through a target well shaft; then soaking is conducted; wherein the temperature of the mixed gas is 80-200 DEG C; 3, when it is detected that the oxygen concentration of gas in the shaft of the target well is lower than the rated concentration, well soaking is ended, and the well is opened for production; and 4, after the step 3 is finished, at least one round of steam huff and puff production is conducted on the target well. According to the method, the high-permeability channel of the heavy oil reservoir can be economically and effectively plugged in situ, so that the recovery efficiency of the heavy oil reservoir is improved

Description

Technical Field

[0001] The present invention relates to the technical field of heavy oil thermal recovery and oil recovery enhancement, and in particular to a method for enhancing the oil recovery of heavy oil gas channeling wells. Background Art

[0002] In the middle and late stages of steam injection in heavy oil reservoirs, there is a common phenomenon of steam "fingering" along high permeability channels, which leads to uneven utilization of reservoir profiles, limited thermal coverage, accelerated production decline, and poor economic benefits. In order to solve the problem of steam channeling caused by high permeability channels and improve the utilization of reservoirs, plugging agents are used to plug high permeability channels to improve reservoir recovery.

[0003] In the middle and late stages of steam injection and huff-and-puff in heavy oil reservoirs, foam, particulate matter, cement slurry, gel, etc. are commonly used to adjust and flood heavy oil reservoirs in order to improve the recovery rate. The advantages of foam adjustment and flooding are good injectability and selective plugging, while the disadvantages are low plugging ability of the channel, short stability time, short validity period, high construction cost, and environmental pollution caused by produced fluid. Particulate adjustment and flooding has problems such as mismatch between particle size and pore size, difficulty of solid particles to stay in the channel, and failure to achieve the effect of plugging. Cement slurry adjustment and flooding has problems such as short solidification time, inability to perform deep plugging, serious blockage of oil layers, and high construction risk. Gel adjustment and flooding has the advantage of good injectability, but poor high temperature resistance. Nowadays, in order to better improve the recovery rate of heavy oil reservoirs, technicians have begun to carry out composite flooding of heavy oil reservoirs by simultaneously implementing multiple flooding methods, such as polymer microsphere-surfactant composite flooding, which first injects a certain amount of polymer microspheres and then injects a certain amount of surfactant. This combines the advantages of two flooding agents, with both the advantages of easy injection and strong regulation ability of polymer microspheres and the advantages of strong oil recovery ability of surfactants and the ability to improve the recovery rate of medium and low permeability channels, which can maximize the oil recovery effect. However, the composite flooding method has problems such as high cost, immature technology, and environmental pollution.

[0004] Based on the problems existing in the existing single and composite flooding technologies, there is an urgent need to explore new technical solutions that can economically and effectively plug the high-permeability channels of heavy oil reservoirs in situ and thus increase the recovery rate of heavy oil reservoirs, so as to improve the production effect of thermal recovery in the middle and late stages of heavy oil reservoirs. Summary of the invention

[0005] The purpose of the present invention is to provide an economical and effective technical solution for in-situ plugging of high permeability channels in heavy oil reservoirs to improve the recovery rate of heavy oil reservoirs.

[0006] In order to achieve the above object, the present invention provides a method for improving the recovery rate of a heavy oil gas channeling well, wherein the method comprises:

[0007] Step 1: Determine the heavy oil reservoir production wells that have undergone steam flooding and / or steam stimulation and have steam channeling as target wells;

[0008] Step 2: injecting a mixture of high-temperature steam and air into the target well formation through the target well bore; then, the well is soaked, and the injected mixture of high-temperature steam and air contacts the heavy oil in the steam channeling channel of the target well formation, causing the heavy oil in the steam channeling channel to be oxidized and thickened to block the steam channeling channel; wherein the temperature of the mixture of high-temperature steam and air is 80-200°C;

[0009] Step 3: When it is detected that the oxygen concentration of the gas in the target wellbore is lower than the rated concentration, the well is shut down and the well is opened for production to produce the unreacted residual gas and the mobile heavy oil in the formation of the target well;

[0010] Step 4: After step 3, perform at least one round of steam stimulation production on the target well.

[0011] The invention provides a method for improving the recovery rate of a heavy oil gas channeling well. The method injects a mixed gas of high-temperature steam and air into a target well formation, so that the mixed gas of high-temperature steam and air contacts the heavy oil in the gas channeling channel of the target well formation. Since the reaction temperature is low and the degree of oxidation in the hydrothermal environment is greater than that in the hydrothermal cracking, the heavy oil in the gas channeling channel mainly undergoes an oxidation reaction (oxygen absorption reaction), the oxygen content in the heavy oil in the gas channeling channel increases, and a viscosity increase phenomenon occurs. The viscosity-increased heavy oil forms an in-situ blockage on the gas channeling channel, thereby realizing the adjustment and displacement of the heavy oil reservoir, thereby improving the recovery rate of the heavy oil reservoir.

[0012] In the method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention, preferably, the method further comprises:

[0013] Step 5: Repeat steps 2-4.

[0014] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, preferably, the air is selected from one of ordinary air, oxygen-reduced air and oxygen-enriched air.

[0015] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, preferably, the volume ratio of high-temperature steam to air in the mixed gas of high-temperature steam and air is 3-25:3; more preferably, the volume ratio of high-temperature steam to air in the mixed gas of high-temperature steam and air is 6:4.

[0016] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, the oxygen concentration of the gas in the wellbore of the target well can be used to determine the degree of oxidation of the heavy oil; preferably, when the oxygen concentration of the gas in the wellbore of the target well is lower than the rated concentration, the degree of oxidation and viscosity increase of the heavy oil in the gas channeling channel has reached the maximum; more preferably, the volume concentration of oxygen in the mixed gas of high-temperature steam and air is 3.5-11.5%, and further preferably is 8.4%.

[0017] In the method for improving recovery of heavy oil gas channeling wells provided by the present invention, preferably, the rated concentration is 0.5-2 Vol% (ie, the volume concentration is 0.5-2%); more preferably, the rated concentration is 1 Vol% (ie, the volume concentration is 1%).

[0018] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, preferably, the injection amount of the mixed gas of high-temperature steam and air satisfies the requirement that the air injection volume of a single well reaches 2.5×10 4 -9.5×10 4 Nm 3 (under standard conditions, i.e. 0°C and 1 atmosphere);

[0019] More preferably, the injection volume of the mixed gas of high-temperature steam and air is sufficient to achieve a single well air injection volume of 5.5×10 4 -9.5×10 4 Nm 3 (under standard conditions, i.e. 0°C and 1 atmosphere).

[0020] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, preferably, the injection pressure of the mixed gas of high-temperature steam and air is 2.0-9.0 MPa.

[0021] In the method for improving the recovery rate of heavy oil gas channeling wells provided by the present invention, preferably, in step 2, after the well is shut down for 3-8 days, the oxygen concentration of the gas in the wellbore of the target well is detected.

[0022] In the method for improving recovery of heavy oil gas channeling wells provided by the present invention, preferably, in step 4, 3-5 rounds of steam stimulation production are performed on the target well.

[0023] In the method for improving the recovery of heavy oil gas channeling wells provided by the present invention, preferably, step 1: determining a heavy oil reservoir production well that has undergone steam flooding and / or steam stimulation and has a steam channeling channel as a target well, comprising:

[0024] Step 1.1, selecting a heavy oil reservoir production well that has undergone steam flooding and / or steam stimulation;

[0025] Step 1.2, verifying whether a steam channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well; if a steam channel is formed, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well is used as a target well;

[0026] More preferably, step 1.2, verifying whether a steam channel is formed in the selected steam flooding and / or steam stimulation heavy oil reservoir production wells, comprises:

[0027] Steam is injected into the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. If there is an adjacent well with a temperature rise and / or an increase in water content, a steam channeling channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. Otherwise, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well does not form a steam channeling channel.

[0028] The method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention injects a mixed gas of high-temperature steam and air at a certain temperature into a heavy oil reservoir formation that has undergone steam flooding and / or steam huff and puff and has a gas channeling channel, so that the heavy oil in the gas channeling channel undergoes oxidation and viscosity increase to achieve in-situ adaptive plugging of the gas channeling channel, thereby achieving heavy oil reservoir adjustment and improvement of the recovery rate of the heavy oil reservoir. The method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention has a simple process and high technical feasibility. The method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention achieves heavy oil reservoir adjustment and displacement by mixed injection of steam and air, does not require the addition of additional chemical reagents, and reduces the adjustment and displacement cost. No other impurities are generated during the adjustment and displacement process of the method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention, and the entire process is green and environmentally friendly. The residual gas after the reaction of the method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention has an energy-enhancing effect. The method for improving the recovery rate of a heavy oil gas channeling well provided by the present invention is suitable for the industrial promotion of plugging and management of heavy oil gas channeling channels. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution provided by the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0030] A specific embodiment of the present invention provides a method for improving the recovery rate of a heavy oil gas channeling well, wherein the method comprises:

[0031] Step S1: determining a heavy oil reservoir production well that has undergone steam flooding and / or steam stimulation and has a steam channel as a target well;

[0032] Step S2: injecting a mixture of high-temperature steam and air into the target well formation through the target well bore; then performing well soaking, the injected mixture of high-temperature steam and air contacts the heavy oil in the steam channeling channel of the target well formation, causing the heavy oil in the steam channeling channel to undergo oxidation and viscosity enhancement to block the steam channeling channel; wherein the temperature of the mixture of high-temperature steam and air is 80-200° C.;

[0033] Step S3: when it is detected that the oxygen concentration of the gas in the wellbore of the target well is lower than the rated concentration, the well is shut down and the well is opened for production to produce the unreacted residual gas and the mobile heavy oil in the formation of the target well;

[0034] Step S4: After step S3, at least one round of steam stimulation production is performed on the target well.

[0035] Furthermore, the method further comprises:

[0036] Step S5: Repeat steps S2-S4.

[0037] Furthermore, the air is selected from one of ordinary air, oxygen-reduced air and oxygen-enriched air.

[0038] Furthermore, the volume ratio of high-temperature steam to air in the mixed gas of high-temperature steam and air is 3-25:3; further, the volume ratio of high-temperature steam to air in the mixed gas of high-temperature steam and air is 6:4.

[0039] Furthermore, the volume concentration of oxygen in the mixed gas of high-temperature steam and air is 3.5-11.5%; further, the volume concentration of oxygen in the mixed gas of high-temperature steam and air is 8.4%.

[0040] Further, the rated concentration is 0.5-2Vol% (ie, the volume concentration is 0.5-2%); further, the rated concentration is 1Vol% (ie, the volume concentration is 1%).

[0041] Furthermore, the injection volume of the mixed gas of high-temperature steam and air is sufficient to meet the single-well air injection volume of 2.5×10 4 -9.5×10 4 Nm 3 (Under the marked conditions, i.e., 0°C and 1 atmosphere); Furthermore, the injection volume of the mixed gas of high-temperature steam and air meets the requirement that the single-well air injection volume reaches 5.5×10 4 -9.5×10 4 Nm 3 (under standard conditions, i.e. 0°C and 1 atmosphere).

[0042] Furthermore, the injection pressure of the mixed gas of high-temperature steam and air is 2.0-9.0 MPa.

[0043] Furthermore, in step S2, after the well is shut down for 3-8 days, the oxygen concentration of the gas in the wellbore of the target well is detected.

[0044] Furthermore, in step S4, 3-5 rounds of steam stimulation production are performed on the target well.

[0045] Further, step S1: determining a heavy oil reservoir production well that has undergone steam flooding and / or steam stimulation and has a steam channel as a target well, comprising:

[0046] Select heavy oil reservoir production wells that have undergone steam flooding and / or steam stimulation;

[0047] Verify whether a steam channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well; if a steam channel is formed, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well is used as a target well;

[0048] Furthermore, the verification of whether a steam channel is formed in the selected heavy oil reservoir production wells subjected to steam flooding and / or steam stimulation includes:

[0049] Steam is injected into the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. If there is an adjacent well with a temperature rise and / or an increase in water content, a steam channeling channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. Otherwise, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well does not form a steam channeling channel.

[0050] Example 1

[0051] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0052] 1. Select Well 1#, a heavy oil reservoir production well that has experienced steam stimulation; verify whether Well 1# has a steam channel. Specifically, inject steam into Well 1#. If there is an increase in temperature and / or water content in the adjacent wells, Well 1# has a steam channel. Otherwise, Well 1# has no steam channel. If Well 1# has a steam channel, Well 1# will be used as the target well.

[0053] During the verification process of whether a steam channel was formed in Well 1#, after steam was injected into Well 1#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 1#, and Well 1# was selected as the target well.

[0054] 2. Mix ordinary air (oxygen content of about 21% by volume) and high-temperature steam in a volume ratio of 3:10 and inject it into the formation of Well 1 through the wellbore of Well 1# until the injection volume of ordinary air reaches 4.0×10 4 Nm 3 When the valve of No. 1 well is closed and the well is soaked, the mixed gas of ordinary air and high-temperature steam injected contacts the heavy oil in the steam channel of No. 1 well formation, causing the heavy oil in the steam channel to oxidize and thicken, thereby blocking the steam channel; wherein, the temperature of the mixed gas of ordinary air and high-temperature steam injected is 80°C;

[0055] 3. In this embodiment, after three days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and mobile heavy oil in the formation of the target well. The physical property analysis of the produced heavy oil shows a viscosity of 17890mPa.s and a viscosity increase rate of 32.5%.

[0056] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0057] During the steam stimulation production process in step 4, the steam injection pressure reached 12.9 MPa, which was significantly higher than the steam injection pressure of 11.6 MPa in the previous steam stimulation process of Well 1#, indicating that the steam channel was blocked. The oil production in a single cycle increased by 243 tons.

[0058] Example 2

[0059] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0060] 1. Select Well 2#, a heavy oil reservoir production well that has experienced steam stimulation. Well 2# is an adjacent well of Well 1#. Verify whether Well 2# has a steam channel. Specifically, inject steam into Well 2#. If the adjacent well has a temperature increase and / or water content increase, Well 2# has a steam channel. Otherwise, Well 2# has no steam channel. If Well 2# has a steam channel, Well 2# is used as the target well.

[0061] During the verification process of whether a steam channel was formed in Well 2#, after steam was injected into Well 2#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 2#, and Well 2# was selected as the target well.

[0062] 2. Mix the oxygen-reduced air (oxygen content of about 10% by volume) and high-temperature steam in a volume ratio of 4:6 and inject it into the formation of Well 2 through the wellbore of Well 2 until the injection volume of the oxygen-reduced air reaches 8.0×10 4 Nm 3 When the valve of No. 2 well is closed and the well is soaked, the mixed gas of oxygen-reduced air and high-temperature steam injected contacts the heavy oil in the steam channeling channel of No. 2 well, causing the heavy oil in the steam channeling channel to be oxidized and thickened, thereby blocking the steam channeling channel; wherein, the temperature of the mixed gas of oxygen-reduced air and high-temperature steam injected is 120°C;

[0063] 3. In this embodiment, after 7 days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and mobile heavy oil in the target well formation. The physical property analysis of the produced heavy oil shows a viscosity of 21700mPa.s and a viscosity increase rate of 60.7%.

[0064] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0065] During the steam stimulation production process in step 4, the steam injection pressure was significantly higher than the steam injection pressure of the 2# well during the previous steam stimulation process, which indicates that the steam channeling channel has been blocked.

[0066] Embodiment 3:

[0067] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0068] 1. Select Well 3#, a heavy oil reservoir production well that has experienced steam stimulation. Well 3# is an adjacent well of Well 1#. Verify whether Well 3# has a steam channel. Specifically, inject steam into Well 3#. If the temperature and / or water content of the adjacent well increases, Well 3# has a steam channel. Otherwise, Well 3# has no steam channel. If Well 3# has a steam channel, Well 3# will be used as the target well.

[0069] During the verification process of whether a steam channel was formed in Well 3#, after steam was injected into Well 3#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 3#, and Well 3# was selected as the target well.

[0070] 2. Mix oxygen-enriched air (oxygen content 30-40% by volume) and high-temperature steam in a volume ratio of 3:10 and inject into the formation of Well 3 through the wellbore of Well 3 until the injection volume of oxygen-enriched air reaches 3.0×10 4 Nm 3 When the valve of Well 3# is closed and the well is soaked, the mixed gas of oxygen-enriched air and high-temperature steam injected contacts the heavy oil in the steam channel of Well 3#, causing the heavy oil in the steam channel to oxidize and thicken, thereby blocking the steam channel; wherein the temperature of the mixed gas of oxygen-enriched air and high-temperature steam injected is 160°C;

[0071] 3. In this embodiment, after 6 days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so the soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and the mobile heavy oil in the formation of the target well. The physical property analysis of the produced heavy oil shows a viscosity of 25300mPa.s and a viscosity increase rate of 87.4%.

[0072] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0073] During the steam stimulation production process in step 4, the steam injection pressure was significantly higher than the steam injection pressure of Well 3# during the previous steam stimulation process, indicating that the steam channel was blocked.

[0074] Embodiment 4:

[0075] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0076] 1. Select Well 4#, a heavy oil reservoir production well that has experienced steam stimulation; verify whether Well 4# has a steam channel. Specifically, inject steam into Well 4#. If there is an increase in temperature and / or water content in the adjacent wells, Well 4# has a steam channel. Otherwise, Well 4# has no steam channel. If Well 4# has a steam channel, Well 4# will be used as the target well.

[0077] During the verification process of whether a steam channel was formed in Well 4#, after steam was injected into Well 4#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 4#, and Well 4# was selected as the target well.

[0078] 2. Mix oxygen-enriched air (oxygen content 30-40% by volume) and high-temperature steam in a volume ratio of 3:20 and inject into the formation of Well 4 through the wellbore of Well 4 until the injection volume of oxygen-enriched air reaches 3.0×10 4 Nm 3 When the valve of Well 4# is closed and the well is soaked, the mixed gas of oxygen-enriched air and high-temperature steam injected contacts the heavy oil in the steam channeling channel of Well 4#, causing the heavy oil in the steam channeling channel to be oxidized and thickened, thereby blocking the steam channeling channel; wherein, the temperature of the mixed gas of oxygen-enriched air and high-temperature steam injected is 140°C;

[0079] 3. In this embodiment, after 7 days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and mobile heavy oil in the target well formation. The physical property analysis of the produced heavy oil shows a viscosity of 10750mPa.s and a viscosity increase rate of 70.6%.

[0080] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0081] During the steam stimulation production process in step 4, the steam injection pressure was significantly higher than the steam injection pressure of the 4# well during the previous steam stimulation process, which indicates that the steam channeling channel has been blocked.

[0082] Embodiment 5:

[0083] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0084] 1. Select Well 5#, a heavy oil reservoir production well that has experienced steam stimulation. Well 5# is an adjacent well of Well 4#. Verify whether a steam channel is formed in Well 5#. Specifically, inject steam into Well 5#. If the temperature and / or water content of the adjacent well increases, then a steam channel is formed in Well 5#. Otherwise, no steam channel is formed in Well 5#. If a steam channel is formed in Well 5#, then Well 5# is used as the target well.

[0085] During the verification process of whether a steam channel was formed in Well 5#, after steam was injected into Well 5#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 5#, and Well 5# was selected as the target well.

[0086] 2. Mix the oxygen-reduced air (oxygen content 10% by volume) and high-temperature steam in a volume ratio of 4:6 and inject it into the formation of Well 5 through the wellbore of Well 5 until the injection volume of the oxygen-reduced air reaches 8.0×10 4 Nm 3 When the valve of Well 5# is closed and the well is soaked, the mixed gas of oxygen-reduced air and high-temperature steam injected contacts the heavy oil in the steam channeling channel of Well 5#, causing the heavy oil in the steam channeling channel to be oxidized and thickened, thereby blocking the steam channeling channel; wherein, the temperature of the mixed gas of oxygen-reduced air and high-temperature steam injected is 140°C;

[0087] 3. In this embodiment, after 7 days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and mobile heavy oil in the formation of the target well. The physical property analysis of the produced heavy oil shows a viscosity of 8290mPa.s and a viscosity increase rate of 31.6%.

[0088] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0089] During the steam stimulation production process in step 4, the steam injection pressure was significantly higher than the steam injection pressure of the 5# well during the previous steam stimulation process, indicating that the steam channel was blocked.

[0090] Embodiment 6:

[0091] This embodiment provides a method for improving the recovery rate of a heavy oil gas channeling well, the method comprising:

[0092] 1. Select Well 6#, a heavy oil reservoir production well that has experienced steam stimulation. Well 6# is an adjacent well of Well 4#. Verify whether a steam channel is formed in Well 6#. Specifically, inject steam into Well 6#. If the temperature and / or water content of the adjacent well increases, Well 6# has a steam channel. Otherwise, Well 6# has no steam channel. If Well 6# has a steam channel, Well 6# will be used as the target well.

[0093] During the verification process of whether a steam channel was formed in Well 6#, after steam was injected into Well 6#, the liquid volume in the adjacent wells increased and the temperature of the produced liquid rose, which proved that a steam channel was formed in Well 6#, and Well 6# was selected as the target well.

[0094] 2. Ordinary air (oxygen content 21% by volume) and high-temperature steam were mixed in a volume ratio of 3:10 and injected into the formation of Well 6 through the wellbore of Well 6# until the injection volume of ordinary air reached 4.0×10 4 Nm 3 At this time, the valve of Well 6# is closed and the well is soaked. The mixed gas of ordinary air and high-temperature steam injected contacts the heavy oil in the steam channel of Well 6#, causing the heavy oil in the steam channel to oxidize and thicken, thereby blocking the steam channel. The temperature of the mixed gas of ordinary air and high-temperature steam injected is 120°C.

[0095] 3. In this embodiment, after 5 days of soaking, it is detected that the oxygen concentration of the gas in the target wellbore is lower than 1Vol%, so soaking is terminated and the well is opened for production until the water content reaches 99% to produce the unreacted residual gas and mobile heavy oil in the formation of the target well. The physical property analysis of the produced heavy oil shows a viscosity of 9750mPa.s and a viscosity increase rate of 61.4%.

[0096] 4. After step 3, steam stimulation production is carried out on the target well; steam stimulation production includes steam injection stage (steam stimulation stage), well shut-in stage (well shut-in stage) and recovery stage (steam exhalation stage).

[0097] The steam injection pressure during the steam stimulation production process in step 4 was significantly higher than the steam injection pressure during the previous steam stimulation process in well 6#, indicating that the steam channel was blocked.

[0098] The above embodiments are only one or more embodiments of this specification. For those skilled in the art, one or more embodiments of this specification may have various changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application should be included in the scope of the claims.

Claims

1. A method for improving the recovery of heavy oil gas channeling wells, wherein: The method includes: Step 1: Determine the heavy oil reservoir production wells that have undergone steam flooding and / or steam stimulation and have steam channeling as target wells; Step 2: injecting a mixture of high-temperature steam and air into the target well formation through the target well borehole; then soaking the well; wherein the temperature of the mixture of high-temperature steam and air is 80-200°C; Step 3: When it is detected that the oxygen concentration of the gas in the wellbore of the target well is lower than the rated concentration, the well is shut down and the well is opened for production; Step 4: After step 3, perform at least one round of steam stimulation production on the target well.

2. The method according to claim 1, wherein: The method further includes: Step 5: Repeat steps 2-4.

3. The method according to claim 1, wherein: The air is selected from one of ordinary air, oxygen-reduced air and oxygen-enriched air.

4. The method according to claim 1, wherein: The volume ratio of high-temperature steam to air in the mixed gas of high-temperature steam and air is 3-25:

3.

5. The method according to claim 1 or 4, wherein: The volume oxygen concentration of the mixed gas of high-temperature steam and air is 4-11%.

6. The method according to claim 1, wherein: The nominal concentration is 0.5-2Vol%.

7. The method according to claim 1 or 2, wherein: The injection volume of the mixed gas of high-temperature steam and air is sufficient to meet the single-well air injection volume of 2.5×10 4 -9.5×10 4 Nm 3 .

8. The method according to claim 1 or 2, wherein: In step 2, after the well has been shut down for 3-8 days, the oxygen concentration of the gas in the wellbore of the target well is detected.

9. The method according to claim 1 or 2, wherein: In step 4, 3-5 rounds of steam stimulation production are performed on the target well.

10. The method according to claim 1 or 2, wherein: Step 1: Identify the heavy oil reservoir production wells that have undergone steam flooding and / or steam stimulation and have steam channeling as target wells, including: Step 1.1, selecting a heavy oil reservoir production well that has undergone steam flooding and / or steam stimulation; Step 1.2, verifying whether a steam channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well; if a steam channel is formed, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well is used as a target well; Wherein, step 1.2, verifying whether a steam channel is formed in the selected steam flooding and / or steam stimulation heavy oil reservoir production wells, comprises: Steam is injected into the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. If there is an adjacent well with a temperature rise and / or an increase in water content, a steam channeling channel is formed in the selected steam-driven and / or steam-stimulated heavy oil reservoir production well. Otherwise, the selected steam-driven and / or steam-stimulated heavy oil reservoir production well does not form a steam channeling channel.