A method for inhibiting fire front channeling in a dip angle reservoir by utilizing fire flood associated gas reinjection

Abstract

This invention belongs to the field of petroleum extraction technology, specifically relating to a method for suppressing fire line advance in dipped reservoirs using associated gas reinjection during fire-driven flooding. In the production process of dipped reservoirs, air is injected into air injection wells; associated gas is injected into production wells located on the updip direction of the air injection wells at a preset rate; other production wells produce using steam injection. When the reservoir combustion fire line advances to the updip production wells, the injection rate of associated gas into the updip production wells is increased. This invention injects associated gas into the updip production wells at the start of production to prevent the fire line from spreading upwards, making the fire line spread more uniform and improving the uniformity of fire line coverage in the reservoir. Furthermore, when the updip production wells experience fire line advance, increasing the injection rate of associated gas promotes the fire line to spread towards the downdip direction or other unaffected areas of the reservoir. This method has the advantages of improving fire line advance in production wells and enhancing the effectiveness of fire-driven flooding.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to a method for suppressing the advance of fire lines in dipped reservoirs by using associated gas reinjection during fire flooding. Background Technology

[0002] Fire flooding, also known as oil layer burning, involves injecting air into a high-viscosity heavy oil layer, causing the crude oil in the layer to undergo a high-temperature oxidation reaction, burning a portion of the crude oil to generate heat and reduce its viscosity, while simultaneously generating a driving force to displace the crude oil.

[0003] The uneven fire line coverage and fire line propagation problems that are widespread during fire-driving operations; in order to solve this problem.

[0004] Chinese patents CN104389571B discloses a method for developing monoclinic reservoirs using fire-firing to improve crude oil recovery rates in high-dipping light and heavy oil reservoirs; CN108894763B discloses a method for storing and utilizing exhaust gas produced by linear fire-firing; CN113445984B discloses a method for fire-firing development of heavy oil reservoirs with edge water intrusion at formation dip angles; and CN113494285B discloses a method for developing heavy oil reservoirs with edge water intrusion at the end of the huff and puff phase. These patents have made improvements in well pattern design and exhaust gas reinjection; however, problems such as uneven fire line coverage and fire line deviation still exist.

[0005] Chinese patent application CN116066038A discloses a step-by-step gas injection development method for oil reservoirs. When the gas-liquid interface migrates to the production well, the production well is converted to gas injection. The gas-liquid interface is developed and developed in a step-by-step manner as a whole. However, there are still problems such as uneven coverage of the fire line and fire line escalation in dipped oil reservoirs.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] To address the technical problems existing in the prior art, this invention provides a method for suppressing fire line propagation in dipped reservoirs using associated gas reinjection during fire-flooding. This invention injects associated gas into production wells in the upward dip direction at the start of production to prevent the fire line from spreading in that direction, making the fire line spread more uniform and improving the uniformity of fire line coverage in the reservoir. Furthermore, when fire line propagation occurs in production wells in the upward dip direction, the injection rate of associated gas is increased to promote the fire line's spread towards the downward dip direction or other unaffected areas of the reservoir, further improving the uniformity of fire line coverage. This method has the advantages of improving fire line propagation in production wells and enhancing the effectiveness of fire-flooding development.

[0008] This invention includes the following technical solutions:

[0009] This invention provides a method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, the method comprising the following steps:

[0010] During the production process of dipped reservoirs, air injection wells inject air; production wells located on the updip direction of air injection wells inject associated gas at a preset rate, and other production wells produce by steam huff and puff.

[0011] When the combustion fire line of the oil reservoir spreads into the production well in the updip direction, the associated gas injection rate of the production well in the updip direction with the fire line spreading should be increased.

[0012] Furthermore, the method for determining whether a production well has a "fire line" has entered the production well is as follows: when the annular pressure of the production well is at the preset pressure, it indicates that the production well has a "fire line" entering the production well.

[0013] Furthermore, the preset pressure is 0.5 to 0.8 MPa.

[0014] Furthermore, when a production well in the updip direction exhibits a flash flood, the associated gas injection rate is Q, which is obtained using the following formula:

[0015] Where K is the formation permeability, A is the cross-sectional area of ​​the oil layer through which the associated gas passes, ΔP is the pressure difference between the updip driving pressure and the formation, μ is the air viscosity at formation temperature, and L is the fire line advance distance.

[0016] Furthermore, the fire-propelled distance L is obtained by the following formula:

[0017] L = V1 * t;

[0018] Where V1 is the upward-tilting fire line expansion speed, and t is the production time after ignition.

[0019] Furthermore, the pressure difference ΔP between the updip driving pressure and the formation is obtained using the following formula:

[0020] ΔP = P3 - P;

[0021] Where P3 is the updip driving pressure and P is the formation pressure.

[0022] Furthermore, when injecting associated gas into a production well with a fire line surging in the updip direction, liquid is simultaneously injected into the production well with the fire line surging to achieve liquid sealing.

[0023] Furthermore, the liquid has the following chemical properties: it contains calcium chloride, which can cause carbon dioxide in the associated gas to precipitate.

[0024] Furthermore, the injection rate of the liquid is 0.1 to 0.3 cubic meters per minute.

[0025] Furthermore, the volume ratio of associated gas injected into the production well with the rapid advance to the volume of injected liquid is 5:1.

[0026] Furthermore, when the fire line of the oil reservoir moves a preset distance in the downward direction and no fire line enters the production well in the upward direction, the production well in the upward direction begins production.

[0027] Further, the moving distance is Lf, which is obtained by the following formula:

[0028]

[0029] Where A0 is the air consumption per unit volume of oil sand determined by indoor experiments, in Nm³. 3 / m 3 ; d is the distance between air injection wells, m; h is the average oil layer thickness, m; P is the bottomhole formation pressure of the air injection well, MPa; P i Atmospheric pressure (MPa); Q is the cumulative air injection volume (Nm³). 3 η is the average O2 utilization rate; Zp is the compressibility factor of air under the formation pressure P at the bottom of the air injection well; Φ is the porosity.

[0030] Furthermore, the preset distance is 1 / 2 to 4 / 7 of the well distance between the air injection well and the downsloping production well.

[0031] Furthermore, the production rate of an updip production well is equal to 1 / 2 to 4 / 7 of the production rate of a downdip production well.

[0032] Furthermore, when the production well in the updip direction starts production and simultaneously produces associated gas, the gas extraction rate of the associated gas in the production well in the updip direction is the first rate.

[0033] When the gas production line advances to 1 / 2 to 2 / 3 of the distance between the air injection well and the production well in the downdip direction, the gas production rate of the production well in the updip direction is the second rate.

[0034] The first velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 1 / 3 to 1 / 2, and the second velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 4 / 7 to 2 / 3.

[0035] Furthermore, when the structured well pattern is a linear well pattern:

[0036] When the fire line of the oil reservoir advances to the production well in the downdip direction, the production well with the fire line advancing in the downdip direction stops production and injects air, and the air injection well stops injecting air and injects associated gas.

[0037] Furthermore, when the structural well pattern is an area well pattern:

[0038] When the combustion fire line of the oil reservoir advances into the production well in the downdip direction, the production well with the fire line advancing in the downdip direction stops production, and then associated gas is injected into the stopped production well.

[0039] Furthermore, when the dip reservoir meets the following conditions: oil layer thickness > 6m, residual oil saturation > 0.35, porosity > 0.20, permeability > 500md, degassed crude oil viscosity under formation conditions < 10000mPa.s, oil layer depth 100m~3500m, reservoir dip angle > 5° and updip fault closure, linear well pattern production is adopted.

[0040] Furthermore, the dip reservoir meets the following conditions: oil layer thickness > 6m, residual oil saturation > 0.35, porosity > 0.20, permeability > 500md, and degassed crude oil viscosity under formation conditions. <10000 mPa.s, oil layer depth> For reservoirs with a depth of 200m, a dip angle of ≤8°, and poor edge and bottom water development, area well pattern production is adopted.

[0041] Furthermore, the control parameters for the steam injection effect are as follows: the steam injection sweep radius is less than half the distance between two adjacent production wells.

[0042] By adopting the above technical solution, the present invention has the following advantages:

[0043] 1. This invention injects associated gas into production wells in the upward dip direction at the start of production to prevent the fire line from spreading in the upward dip direction, making the fire line spread more uniform and improving the uniformity of fire line coverage in the reservoir; while increasing the injection rate of associated gas when the fire line in the production wells in the upward dip direction is amplified, promoting the fire line to spread to the downward dip direction of the reservoir or other unaffected areas, thus improving the uniformity of fire line coverage in the reservoir; it has the advantages of improving the fire line spread in production wells and enhancing the effectiveness of fire-driven development.

[0044] 2. This invention determines whether the fire line has spread to the production well by using preset conditions of associated gas, which has the advantage of high judgment accuracy.

[0045] 3. By controlling the injection rate of associated gas, this invention can further suppress the continued advance of the fire line, causing the fire line to spread towards the downdip direction of the reservoir or other unaffected areas, thereby improving the uniformity of the fire line spread in the reservoir.

[0046] 4. This invention uses associated gas reinjection production wells, which not only reduces fire-driven exhaust gas emissions but also reduces associated gas treatment costs; it has the advantages of good economic benefits and avoidance of environmental pollution.

[0047] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a flowchart of a method for suppressing fire line advance in dip reservoirs using associated gas reinjection during fire flooding, as described in an embodiment of the present invention.

[0050] Figure 2 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 1 ;

[0051] Figure 3 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 2 ;

[0052] Figure 4 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 3 ;

[0053] Figure 5 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 4 ;

[0054] Figure 6 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 5 ;

[0055] Figure 7 This is a schematic diagram of the production process of the linear well network in an embodiment of the present invention. Figure 6 ;

[0056] Figure 8 This is a schematic diagram of the production process of the area well network in an embodiment of the present invention. Figure 1 ;

[0057] Figure 9 This is a schematic diagram of the production process of the area well network in an embodiment of the present invention. Figure 2 ;

[0058] Figure 10 This is a schematic diagram of the production process of the area well network in an embodiment of the present invention. Figure 3 ;

[0059] Figure 11 This is a schematic diagram of the production process of the area well network in an embodiment of the present invention. Figure 4 ;

[0060] Figure 12 This is a schematic diagram of gas injection for a structured well network in an embodiment of the present invention. Detailed Implementation

[0061] The following description provides many different embodiments or examples for implementing various features of the invention. The elements and arrangements described in the specific examples below are only for concise expression of the invention and are merely examples, not intended to limit the invention.

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] This embodiment provides a method for suppressing the advance of the fire line in dip-angled reservoirs by using associated gas reinjection during fire flooding. Figure 1 As shown, the method includes the following steps:

[0064] There are two types of associated gas: one is flue gas generated during the combustion of oil reservoirs, and the other is formed by the combustion of natural gas using steam injection wells. Because of the density difference between gas and liquid, gas rises in a fluid due to gravity, causing flue gas to prematurely enter the updip direction. Updip production wells, by injecting associated gas, increase the updip pressure, which can reduce the advance rate of the fire line. Therefore, dipped reservoirs are produced using a structured well network. During production in dipped reservoirs, air injection wells inject air; production wells located on the updip direction of the air injection wells inject associated gas at a preset rate; and the remaining production wells produce using a steam huff and puff method.

[0065] The structured well network can be a linear well network or an area well network, and other forms of structured well networks should also be within the scope of protection of this invention; in the linear well network, an air injection well is set between two adjacent rows of production wells, and in the area well network, an air injection well is set in the middle of the production wells.

[0066] Specifically, such as Figure 2 The diagram shows a linear well network production process. In the diagram, air is injected into the air injection wells, and associated gas is injected into the production wells located on the updip direction of the air injection wells at a preset speed. This method can suppress the spread of the fire line in the updip direction and improve the uniformity of the fire line spread.

[0067] like Figure 8 The diagram shows a schematic of the production process of an area well network. In the diagram, air is injected into the air injection well, and associated gas is injected into the production well located in the upward tilt direction of the air injection well at a preset speed. In this way, the spread of the fire line in the upward tilt direction can be suppressed, and the uniformity of the fire line spread can be improved.

[0068] When the combustion fire line in the reservoir extends into a production well in the updip direction, the associated gas injection rate of the production well in the updip direction with the combustion fire line extending into it should be increased. Specifically, for example... Figure 3 As shown, in a linear well network, production wells in the updip direction exhibit flash flooding, which increases the associated gas injection rate of production wells with flash flooding; for example... Figure 9 As shown, production wells in the updip direction of the area well network have fire-line advance, which increases the associated gas injection rate of production wells with fire-line advance.

[0069] Whether a production well has experienced a flash flood can be determined by direct observation, but this method has low safety and accuracy. Therefore, in order to improve safety and accuracy, in some embodiments, the method for determining whether a flash flood has occurred in a production well is: when the annular pressure of the production well is at a preset pressure, it indicates that the production well has experienced a flash flood.

[0070] In some embodiments, the preset pressure is 0.5 to 0.8 MPa.

[0071] To create a high-pressure gas cap in the updip portion of the reservoir, further suppressing the fire line's advance and directing it towards the downdip direction or other unaffected areas, thus improving the uniformity of fire line coverage, in some embodiments, the injection rate of the associated gas is Q, which is obtained using the following formula:

[0072] Where K is the formation permeability, A is the cross-sectional area of ​​the oil layer through which the associated gas passes, ΔP is the pressure difference between the updip driving pressure and the formation, μ is the air viscosity at formation temperature, and L is the fire line advance distance.

[0073] In some embodiments, the fire-propelled distance L is obtained by the following formula:

[0074] L = V1 × t;

[0075] Where V1 is the upward-tilting fire line expansion speed, and t is the production time after ignition.

[0076] like Figure 12As shown, during normal production in a structured well network (including area well networks, linear well networks, etc.), air is injected through air injection wells. Each air injection well injects air into the well according to the wellhead injection pressure P1. The updip driving pressure P3 of the air injection well can be obtained by using the injection pressure P1 and the dip angle θ of the dip reservoir. After injecting associated gas into a production well with fire-drive propagation in the updip direction, it has a downdip driving pressure P4. When P3 = P4, fire-drive propagation can be effectively suppressed while reducing the use of associated gas. Therefore, in some embodiments, the pressure difference ΔP between the updip driving pressure and the formation is obtained by the following formula:

[0077] ΔP = P3 - P;

[0078] Where P3 is the updip driving pressure and P is the formation pressure at the bottom of the air injection well.

[0079] In some embodiments, the upward tilting driving pressure P3 is obtained by the following formula:

[0080]

[0081] Where P2 is the bottom hole injection pressure of the air injection well, and θ is the reservoir dip angle.

[0082] In some embodiments, the bottom-hole injection pressure P2 of the air injection well is obtained by the following formula:

[0083] P2 = P1 + ρgH;

[0084] Where P1 is the injection pressure at the wellhead of the air injection well, ρ is the density of the gas column in the wellbore, g is the acceleration due to gravity, and H is the height of the liquid column in the wellbore.

[0085] In some embodiments, when associated gas is injected into a production well with a fire-line runoff in the updip direction, liquid is simultaneously injected into the production well to achieve a liquid seal. For example... Figure 3 As shown, in this linear well network, the production wells in the updip direction have a rapid advance, so the injection rate of associated gas into the production well is increased, and liquid is also injected into the production well to achieve liquid sealing.

[0086] In some embodiments, the liquid has the following chemical properties: it contains calcium chloride, which can cause carbon dioxide in the associated gas to precipitate. Calcium chloride reacts with carbon dioxide to form calcium carbonate precipitate; after the fire line has entered the channel, the channel contains a large amount of gas. With the presence of calcium carbonate precipitate, some of the pore throat channels become smaller, reducing the gas volume in the channel and decreasing the degree of fire line entry, thereby effectively inhibiting further fire line entry.

[0087] In some embodiments, the injection rate of the liquid is 0.1 to 0.3 cubic meters per minute.

[0088] In some embodiments, the volume ratio of associated gas injected into a production well with a flash flood to the volume of injected liquid is 5:1. Preferably, the associated gas and the liquid are injected using a slug injection method.

[0089] In some embodiments, such as Figure 4 As shown, when the fire line in the reservoir moves a preset distance in the downward dip direction, and no fire line enters the production well in the upward dip direction, as... Figure 5 As shown, the production well in the upward-sloping direction begins production. The preset distance is 1 / 2 to 4 / 7 of the distance between the air injection well and the production well in the downward-sloping direction; it should be noted that 1 / 2 to 4 / 7 can be any value between 1 / 2 and 4 / 7. Figure 5 As can be seen, the fire line between the first air injection well on the left and the downsloping direction is exactly located at 1 / 2 of the well distance between the air injection well and the downsloping production well.

[0090] In some embodiments, the production rate of an updip production well is equal to 1 / 2 to 4 / 7 of the production rate of a downdip production well. It should be noted that 1 / 2 to 4 / 7 can be any value between 1 / 2 and 4 / 7.

[0091] In some embodiments, when an updip production well begins production and simultaneously produces associated gas, the gas extraction rate of the associated gas from the updip production well is a first rate.

[0092] When the gas extraction line advances to 1 / 2 to 2 / 3 of the distance between the air injection well and the production well in the downdip direction, it should be noted that 1 / 2 to 2 / 3 can be any value between 1 / 2 and 2 / 3; the gas extraction rate of the production well in the updip direction is the second rate.

[0093] The first velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 1 / 3 to 1 / 2. It should be noted that 1 / 3 to 1 / 2 can be any value between 1 / 3 and 1 / 2. The second velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 4 / 7 to 2 / 3. It should be noted that 4 / 7 to 2 / 3 can be any value between 4 / 7 and 2 / 3.

[0094] It should be noted that, Figure 5 The fire line between the first air injection well on the left and the downsloping direction, located exactly at half the distance between the air injection well and the downsloping production well, is merely illustrative. This fire line, located at exactly half the distance between the air injection well and the downsloping production well, should also be within the scope of protection of this invention even if it is located elsewhere. It should also be noted that... Figure 4 , Figure 5This is a schematic diagram of a linear well pattern and does not imply any limitation on the invention. Area well patterns are also within the scope of protection of this invention.

[0095] In some embodiments, the travel distance is Lf, which is obtained by the following formula:

[0096]

[0097] Where A0 is the air consumption per unit volume of oil sand determined by indoor experiments, in Nm³. 3 / m 3 ; d is the distance between air injection wells, m; h is the average oil layer thickness, m; P is the bottomhole formation pressure of the air injection well, MPa; P i Atmospheric pressure (MPa); Q is the cumulative air injection volume (Nm³). 3 η is the average O2 utilization rate; Zp is the compressibility factor of air under the formation pressure P at the bottom of the air injection well; Φ is the porosity.

[0098] In some embodiments, when the structured well pattern is a linear well pattern:

[0099] like Figure 6 As shown, when the reservoir combustion fire line advances to the production well in the downdip direction, such as Figure 7 As shown, the production well with the fire line rushing in the downward tilting direction stops production and injects air, and the air injection well stops injecting air and injects associated gas.

[0100] In some embodiments, when the structured well pattern is an area well pattern:

[0101] like Figure 10 As shown, when the reservoir combustion fire line advances to the production well in the downdip direction, such as Figure 11 As shown, the production well with the fire line rushing in the downward tilt direction stops production, and then associated gas is injected into the stopped production well.

[0102] In some embodiments, the reservoir thickness is >6m, residual oil saturation is >0.35, porosity is >0.20, permeability is >500md, degassed crude oil viscosity under formation conditions is <10000mPa·s, reservoir depth is 100m~3500m, reservoir dip angle is >5°, and updip fault closure is present. When the dip reservoir conditions meet the above conditions, production is carried out through a linear well pattern.

[0103] In some embodiments, the oil layer thickness is >6m, the residual oil saturation is >0.35, the porosity is >0.20, the permeability is >500md, and the viscosity of the degassed crude oil under formation conditions is [value missing]. <10000 mPa.s, oil layer depth> 200m, reservoir dip angle ≤ 8°, and no edge and bottom water development. When a dip reservoir meets the above conditions, production is carried out through area well patterning.

[0104] In some embodiments, the control parameters for the steam injection effect are: the steam injection sweep radius is less than half the well distance between two adjacent production wells.

[0105] It should be noted that, Figures 2-11 The number of production wells and air injection wells shown is illustrative and does not represent a limitation. It should also be noted that the number of production wells with rapid expansion in both linear and area well networks shown in the diagram is also illustrative.

[0106] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0107] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, characterized in that, The method includes the following steps: During the production process of dipped reservoirs, air injection wells inject air; production wells located on the updip direction of air injection wells inject associated gas at a preset rate, and other production wells produce by steam huff and puff. When the combustion fire line of the oil reservoir spreads into the production well in the updip direction, the associated gas injection rate of the production well in the updip direction with the fire line spreading should be increased.

2. The method for suppressing fire line advance in dip-angled reservoirs by using associated gas reinjection during fire flooding according to claim 1, characterized in that, The method for determining whether a production well has a "fire line" has entered the production well is as follows: when the annular pressure of the production well is at the preset pressure, it indicates that the production well has a "fire line" entering the production well.

3. The method for suppressing fire line advance in dip-angled reservoirs by using associated gas reinjection during fire flooding according to claim 2, characterized in that, The preset pressure is 0.5 to 0.8 MPa.

4. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in any one of claims 1-3, characterized in that... When a production well in the updip direction experiences a flash flood, the associated gas injection rate is Q, which is obtained by the following formula: Where K is the formation permeability, A is the cross-sectional area of ​​the oil layer through which the associated gas passes, ΔP is the pressure difference between the updip driving pressure and the formation, μ is the air viscosity at formation temperature, and L is the fire line advance distance.

5. The method for suppressing fire line advance in dip-angled reservoirs by using associated gas reinjection during fire flooding according to claim 4, characterized in that, The fire line advance distance L is obtained by the following formula: L = V1 * t; Where V1 is the upward-tilting fire line expansion speed, and t is the production time after ignition.

6. The method for suppressing fire line advance in dip-angled reservoirs by using associated gas reinjection during fire flooding according to claim 4, characterized in that, The pressure difference ΔP between the updip driving pressure and the formation is obtained by the following formula: ΔP = P3 - P; Where P3 is the updip driving pressure and P is the formation pressure.

7. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 1, characterized in that... When injecting associated gas into a production well with a fire line surging in the updip direction, liquid is simultaneously injected into the production well with the fire line surging to achieve liquid sealing.

8. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 7, is characterized in that... The liquid has the following chemical properties: it contains calcium chloride, which can cause carbon dioxide in the associated gas to precipitate.

9. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 7, characterized in that... The injection rate of the liquid is 0.1 to 0.3 cubic meters per minute.

10. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 7, characterized in that... The volume ratio of associated gas injected into a production well with a rapid advance to the volume of injected liquid is 5:

1.

11. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 1, characterized in that... When the fire line in the reservoir moves a predetermined distance in the downward direction and no fire line enters the production well in the upward direction, the production well in the upward direction begins production.

12. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 11, characterized in that... The moving distance is Lf, which is obtained by the following formula: Where A0 is the air consumption per unit volume of oil sand determined by indoor experiments, in Nm³. 3 / m 3 ; d is the distance between air injection wells, m; h is the average oil layer thickness, m; P is the bottomhole formation pressure of the air injection well, MPa; P i Atmospheric pressure (MPa); Q is the cumulative air injection volume (Nm³). 3 η is the average O2 utilization rate; Zp is the compressibility factor of air under the formation pressure P at the bottom of the air injection well; Φ is the porosity.

13. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 12, characterized in that... The preset distance is 1 / 2 to 4 / 7 of the distance between the air injection well and the production well in the downsloping direction.

14. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 11, characterized in that... The production rate of an updip production well is equal to 1 / 2 to 4 / 7 of the production rate of a downdip production well.

15. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 14, characterized in that... When an updip production well starts production and simultaneously produces associated gas, the gas extraction rate of the associated gas from the updip production well is the first rate. When the gas production line advances to 1 / 2 to 2 / 3 of the distance between the air injection well and the production well in the downdip direction, the gas production rate of the production well in the updip direction is the second rate. The first velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 1 / 3 to 1 / 2, and the second velocity is equal to the gas production rate of associated gas in production wells with a downdip direction of 4 / 7 to 2 / 3.

16. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in any one of claims 11-15, characterized in that... When using a linear well pattern for production in dip reservoirs: When the fire line of the oil reservoir advances to the production well in the downdip direction, the production well with the fire line advancing in the downdip direction stops production and injects air, and the air injection well stops injecting air and injects associated gas.

17. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in any one of claims 11-15, characterized in that, When using area well pattern production in dip reservoirs: When the combustion fire line of the oil reservoir advances into the production well in the downdip direction, the production well with the fire line advancing in the downdip direction stops production, and then associated gas is injected into the stopped production well.

18. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 1, characterized in that... When the dip reservoir meets the following conditions: reservoir thickness > 6m, residual oil saturation > 0.35, porosity > 0.20, permeability > 500md, degassed crude oil viscosity under formation conditions < 10000mPa.s, reservoir depth 100m~3500m, reservoir dip angle > 5° and updip fault closure, linear well pattern production is adopted.

19. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 1, characterized in that... The dip reservoir meets the following conditions: oil layer thickness > 6m, residual oil saturation > 0.35, porosity > 0.20, permeability > 500md, and degassed crude oil viscosity under formation conditions. <10000 mPa.s, oil layer depth> For reservoirs with a depth of 200m, a dip angle of ≤8°, and poor edge and bottom water development, area well pattern production is adopted.

20. A method for suppressing fire line advance in dip-angled reservoirs using associated gas reinjection during fire flooding, as described in claim 1, characterized in that... The control parameters for the steam injection effect are: the steam injection sweep radius is less than half the distance between two adjacent production wells.

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