A well group and single well plugging method for condensate gas reservoir anti-condensate damage

Abstract

The application discloses a well group and single well plugging removal method for condensate gas reservoir reverse condensation damage, the well group plugging removal method for condensate gas reservoir reverse condensation damage determines the air injection amount according to the reverse condensation damage distribution range of the condensate gas reservoir; selects a well from the well group to be an air injection well, injects air into the air injection well according to the air injection amount, ignites at the air injection well midpoint when reaching the first set time; determines the plugging removal success according to the current wellhead pressure drop of the air injection well and / or the oil production drop of the production well in the well group, stops the air injection, and injects nitrogen into the air injection well to extinguish the fire. The application has flexible operation mode, can effectively remove the reservoir damage caused by the condensate gas reservoir reverse condensation phenomenon, has wide action range, and has good plugging removal effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of condensate gas reservoir engineering, and particularly relates to a well group plugging removal method for condensate gas reservoir retrograde condensation damage and a single well plugging removal method. BACKGROUND

[0002] Condensate gas reservoir is a kind of gas reservoir which is more "delicate" among all types of oil and gas reservoirs, but it also has high economic value. Condensate gas reservoir is different from ordinary oil reservoir or gas reservoir, which has the dual characteristics of oil reservoir and gas reservoir. During the production process, the condensate gas will undergo very complex phase changes with the change of pressure. During the depletion production process of the condensate gas reservoir, when the bottom hole pressure is lower than the dew point pressure of the formation condensate gas, the heavy components of the formation fluid will be precipitated to cause retrograde condensation phenomenon, and it occurs earliest in the near wellbore zone. The production layer changes from single-phase flow to two-phase flow. When the condensate oil saturation is lower than the critical flow saturation, the retrograde condensate oil will continuously accumulate, causing a significant reduction in effective permeability and affecting the production capacity of the reservoir, which is a kind of reservoir plugging and damage caused by retrograde condensation. SUMMARY

[0003] The present application relates to the technical field of condensate gas reservoir engineering, and particularly relates to a well group plugging removal method for condensate gas reservoir retrograde condensation damage and a single well plugging removal method.

[0004] Therefore, there is no special effective and complete plugging removal method for the retrograde condensation phenomenon of the condensate gas reservoir. How to effectively remove the retrograde condensation damage and improve the production of the condensate gas reservoir is a technical problem to be solved.

[0005] In order to at least partially solve the technical problems existing in the prior art, the present application is made by the inventors, and through specific embodiments, a well group plugging removal method for condensate gas reservoir retrograde condensation damage and a single well plugging removal method are provided, which can effectively remove the retrograde condensation damage of the condensate gas reservoir and have a wide range of action.

[0006] In a first aspect, an embodiment of the present application provides a well group plugging removal method for condensate gas reservoir retrograde condensation damage, comprising:

[0007] determine the air injection amount according to the retrograde condensate damage distribution range of the condensate gas reservoir, the retrograde condensate damage distribution range being a retrograde condensate damage distribution range of a well group;

[0008] select a well from the well group to be changed into an air injection well, inject air into the air injection well according to the air injection amount, and ignite in the air injection well when a first set time is reached;

[0009] If it is determined that the deblocking is successful according to the decrease amplitude of the current wellhead pressure of the air injection well and / or the decrease amplitude of the oil production of the production well in the well group, stop the injection of air, and inject nitrogen into the air injection well to extinguish the fire.

[0010] In a second aspect, the embodiment of the present application provides a single-well deblocking method for retrograde condensate damage of a condensate gas reservoir, comprising:

[0011] determine the air injection amount according to the retrograde condensate damage distribution range of the condensate gas reservoir, the retrograde condensate damage distribution range being a retrograde condensate damage distribution range of a single well;

[0012] change the well into an air injection well, inject air into the air injection well according to the air injection amount, ignite in the air injection well when a first set time is reached, stop the injection of air when the current wellhead pressure reaches a set pressure condition, and change the air injection well into a production well to produce oil after a second set time of huff and puff;

[0013] If it is determined that the deblocking is successful according to the decrease amplitude of the current wellhead pressure of the production well and / or the decrease amplitude of the oil production, inject nitrogen into the production well to extinguish the fire.

[0014] The beneficial effects of the above technical solutions provided by the embodiment of the present application at least include:

[0015] (1) The well group deblocking method for retrograde condensate damage of a condensate gas reservoir provided by the embodiment of the present application determines the air injection amount according to the retrograde condensate damage distribution range of the condensate gas reservoir, selects a well from the well group to be changed into an air injection well, injects air into the air injection well according to the air injection amount, ignites in the air injection well when a first set time is reached, and if it is determined that the deblocking is successful according to the decrease amplitude of the current wellhead pressure of the air injection well and / or the decrease amplitude of the oil production of the production well in the well group, stops the injection of air and injects nitrogen into the air injection well to extinguish the fire. The ignition is performed by injecting air, the chemical reaction between oxygen in the air and part of the retrograde condensate oil in the condensate gas reservoir is used to block part of the retrograde condensate oil in the wellbore as fuel, and then the continuation of the oxidation reaction is maintained, so as to finally achieve the purpose of complete deblocking. The well is selected from the well group to be changed into an air injection well, air is injected into the air injection well and ignited, part of the retrograde condensate oil in the wellbore is used as fuel, the burning range can extend from the air injection well to the surrounding production wells, and therefore the reservoir damage between the injection and production wells with a long distance and a large retrograde condensate damage range can be removed.

[0016] (2) The well group unblocking method for anti-condensate damage in condensate gas reservoirs provided in this embodiment of the invention uses only a small proportion of anti-condensate oil as fuel, and most of the remaining anti-condensate oil blocking the wellbore can be extracted, minimizing the loss of anti-condensate oil and resulting in significant economic benefits. At the same time, due to the unblocking operation, the reservoir permeability is restored, and the generated heat and produced gas have a certain energy-boosting and pressure-replenishing effect on the reservoir, which can effectively improve the reservoir condition of condensate gas reservoirs. Therefore, after the unblocking operation is stopped, production can be resumed in the original production mode, and the gas well can maintain a high production rate for a longer period of time, thereby improving the natural gas recovery rate compared with conventional unblocking methods. At the same time, the unblocking operation is relatively simple and has a low cost.

[0017] (3) The single-well unblocking method for reverse condensate damage in condensate gas reservoirs provided in this embodiment of the invention involves converting the single well into an air injection well, injecting air into the air injection well, igniting it in the air injection well when a first set time is reached, stopping the air injection when the current wellhead pressure reaches the set pressure condition, and shutting the well for a second set time before converting the air injection well into a production well for oil production; if the unblocking is determined to be successful based on the decrease in the current wellhead pressure and / or the decrease in oil production of the production well, nitrogen is injected into the production well for extinguishing the fire. The single well with reverse condensate damage around the wellbore is first used as an air injection well, air is injected and ignited, and then converted into a production well to extract the unburned reverse condensate oil blocking the wellbore. This not only unblocks the reverse condensate damage around the wellbore but also extracts most of the unburned reverse condensate oil blocking the wellbore; at the same time, the unblocking range is wide and can remove all reverse condensate damage extending around the wellbore.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a flowchart of the well group unblocking method for anti-condensation damage in condensate gas reservoirs in Embodiment 1 of the present invention;

[0021] Figure 2 This is a flowchart of a single-well unblocking method for anti-condensation damage in condensate gas reservoirs in Embodiment 2 of the present invention;

[0022] Figure 3 This is a flowchart illustrating the specific implementation of the single-well unblocking method for anti-condensation damage in condensate gas reservoirs in Embodiment 3 of the present invention. Detailed Implementation

[0023] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] In the description of this invention, it should be noted that the terms "comprising," "including," "having," "containing," etc., are all open-ended terms, meaning that they include but are not limited to. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] To address the problem that existing technologies cannot effectively and thoroughly resolve the reverse condensation phenomenon in condensate gas reservoirs, this invention provides a method for unblocking well groups and individual wells in response to reverse condensation damage in condensate gas reservoirs. This method can effectively relieve reverse condensation damage in condensate gas reservoirs and has a wide range of applications.

[0028] By using dynamic analysis and numerical simulation of condensate gas reservoirs, the planar and vertical distribution range of the anti-condensate damage reservoir and the oil content of the anti-condensate oil can be estimated. Based on its planar distribution range, if it is determined that the anti-condensate damage around a single well has not extended to surrounding wells, the single-well unblocking method in the following embodiments is adopted; if it is determined that the anti-condensate damage around a single well has extended to surrounding wells, that is, the anti-condensate damage occurs within the well group, the well group unblocking method in the following embodiments is adopted.

[0029] Example 1

[0030] Embodiment 1 of the present invention provides a method for unblocking well groups suffering from reverse condensation damage in condensate gas reservoirs, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0031] Step S11: Determine the air injection rate based on the distribution range of anti-condensation damage in the condensate gas reservoir.

[0032] The distribution range of anti-condensate damage is the distribution range of anti-condensate damage in the well group, that is, the anti-condensate damage around the wellbore of a single well has extended to the surrounding wells.

[0033] In some embodiments, the air injection rate is determined based on the average distribution area of ​​anti-condensation damage in the horizontal direction and the average distribution height in the vertical direction of the condensate gas reservoir.

[0034] Furthermore, based on the average horizontal distribution area S and the average vertical distribution height h of the anti-condensation damage in the condensate gas reservoir, the daily air injection rate Q is determined using the following formula. air :

[0035] Q air =0.82Sh.

[0036] Step S12: Select a well from the well group and change it to an air injection well. Inject air into the air injection well according to the air injection rate. When the first set time is reached, ignite the air injection well.

[0037] Generally, wells located in the center of the well group are selected. These wells can be either injection wells or production wells. The selected wells are then shut in, the accumulated fluid in the well cavity is removed, and they are converted into air injection wells.

[0038] The first set time can be set by comprehensively considering the horizontal and vertical distribution range of the reservoir damaged by anti-condensation and the oil content of the anti-condensation oil. Generally, the first set time can be set to 5 to 10 days.

[0039] Air is injected into the air injection well according to the air injection volume. You can start by injecting a small amount of air into the air injection well and gradually increase the injection volume until it stabilizes at the air injection volume determined in step S11.

[0040] After the air injection time reaches the first set time, the ignition temperature is maintained at the set ignition temperature by monitoring the temperature of the ignition equipment. If the condensate gas reservoir is a light oil condensate gas reservoir, the ignition temperature in the air injection well is controlled above 300℃; if the condensate gas reservoir is a heavy oil condensate gas reservoir, the ignition temperature in the air injection well is controlled above 450℃.

[0041] After ignition, the anticondensate oil blocking the wellbore reacts fully with oxygen in the air underground, achieving underground combustion.

[0042] In some embodiments, after ignition in the air injection well, the process may further include:

[0043] Monitor whether the CO2 content in the gas produced by the production wells in the monitoring well group reaches the set content threshold; if yes, confirm successful ignition; if not, re-ignite in the air injection well until the CO2 content in the gas produced by the production wells in the monitoring well group reaches the set content threshold.

[0044] Furthermore, the produced gas from the production well can be monitored and analyzed by gas chromatography to determine the CO2 content of the produced gas.

[0045] The content threshold can be set at 12%.

[0046] Once ignition is confirmed to be successful, the air injection rate can be gradually increased. For example, the daily air injection rate can be increased to the air injection rate determined in step S11 within one month.

[0047] Step S13: If the unblocking is successful based on the decrease in the current wellhead pressure of the air injection well and / or the decrease in the oil production of the production wells in the well group, stop the air injection and inject nitrogen into the air injection well to extinguish the fire.

[0048] After ignition, the unblocking stage begins. As the underground combustion front continues to advance, some of the anti-condensate oil that caused the wellbore blockage is consumed as fuel. The remaining anti-condensate oil will be pushed to the production well end by the combustion front and extracted along with the flue gas through the production well. At this time, the oil production level of the production well will gradually increase and reach a stable level.

[0049] The significant decrease in pressure at the injection well indicates that the other end of the well group (the production well) has become unblocked, meaning that the gas injection well, the production well, and the reservoir between them have been largely unblocked. The oil production level of the production well begins to drop rapidly. Alternatively, combined with other relevant dynamic analyses, it can be determined that the anti-condensate oil causing the blockage has been removed, the reservoir has returned to its original level, and the blockage has been successfully resolved.

[0050] Once the blockage is deemed successfully cleared, air injection is stopped, the injection well is shut down, and nitrogen sluice gate injection is initiated for underground fire suppression. Subsequently, the production well's extraction method is switched back to the condensate gas reservoir extraction method used before the blockage was cleared. If the selected air injection well was originally a production well, it is converted back to a production well, and the extraction method is switched back to the original condensate gas reservoir extraction method.

[0051] The well group unblocking method for anti-condensate damage in condensate gas reservoirs provided in Embodiment 1 of this invention determines the air injection volume based on the distribution range of anti-condensate damage in the condensate gas reservoir, converts the screening well in the well group into an air injection well, injects air into the air injection well according to the air injection volume, and ignites it in the air injection well after a first set time. If the unblocking is determined to be successful based on the current wellhead pressure drop of the air injection well and / or the oil production drop of the production wells in the well group, the air injection is stopped, and nitrogen is injected into the air injection well for extinguishing. Ignition through air injection allows oxygen in the air to chemically react with some of the anti-condensate oil in the condensate gas reservoir, using the anti-condensate oil blocking the wellbore as fuel, thereby maintaining the oxidation reaction and ultimately achieving complete unblocking. Converting the screening well in the well group into an air injection well, injecting air into the air injection well and igniting it, using the anti-condensate oil blocking the wellbore as fuel, allows the combustion range to extend from the air injection well to the surrounding production wells, thus relieving reservoir damage over long distances and with a large anti-condensate damage range between injection and production wells.

[0052] Only a small proportion of the anti-condensate oil is used as fuel; the majority of the remaining anti-condensate oil blocking the wellbore can be extracted, minimizing its loss and resulting in significant economic benefits. Simultaneously, the unblocking operation restores reservoir permeability, and the generated heat and produced gas have a certain energy-boosting and pressure-replenishing effect on the reservoir, effectively improving the reservoir condition of the condensate gas reservoir. Therefore, after the unblocking operation ceases, production can resume at the original extraction method, and the gas well can maintain a high and stable production rate for a longer period, thus improving the natural gas recovery rate compared to conventional unblocking methods. Furthermore, the unblocking operation is relatively simple and has a lower cost.

[0053] Example 2

[0054] Embodiment 2 of the present invention provides a single-well unblocking method for reverse condensation damage in condensate gas reservoirs, the process of which is as follows: Figure 2 As shown, it includes the following steps:

[0055] Step S21: Determine the air injection rate based on the distribution range of anti-condensation damage in the condensate gas reservoir.

[0056] The distribution range of anti-condensate damage is the distribution range of anti-condensate damage in a single well, that is, the anti-condensate damage around the wellbore of a single well does not extend to surrounding wells.

[0057] The daily air injection rate Q can be determined using the following formula, based on the average horizontal distribution area S and the average vertical distribution height h of the anti-condensation damage in the condensate gas reservoir. air :

[0058] Q air =0.82Sh.

[0059] Step S22: Change the well to an air injection well, inject air into the air injection well according to the air injection volume, and ignite in the air injection well when the first set time is reached.

[0060] A single well could originally be either an injection well or a production well. First, the well is shut down and the accumulated fluid in the well cavity is removed, then it is converted into an air injection well.

[0061] If the condensate gas reservoir is a light oil condensate gas reservoir, the ignition temperature in the air injection well should be controlled above 300℃; if the condensate gas reservoir is a heavy oil condensate gas reservoir, the ignition temperature in the air injection well should be controlled above 450℃.

[0062] Step S23: Once the current wellhead pressure reaches the set pressure condition, stop the air injection and, after the second set time of well shut-in, convert the air injection well into a production well for oil production.

[0063] When the difference between the current wellhead pressure and the wellhead pressure before air injection is less than the set difference threshold, that is, when the current wellhead pressure is close to the wellhead pressure before air injection, stop the air injection, close the air injection well, and shut down the well for the second set time, which can be 3 to 5 days.

[0064] After the well is shut down, it is reopened for production recovery, and attention is paid to monitoring the produced gas. It can be seen that as the flue gas is discharged, the oil production also increases significantly and remains stable for a period of time.

[0065] Step S24: If the unblocking is successful based on the decrease in the current wellhead pressure and / or the decrease in oil production, inject nitrogen into the production well to extinguish the fire.

[0066] When the oil production level drops rapidly and the casing pressure also begins to fall significantly, it can be determined that the anti-condensate oil that caused the blockage near the single well has been removed, the reservoir has returned to its original level, and the blockage has been successfully cleared.

[0067] After injecting nitrogen into the production well to extinguish the fire, the well is shut in. Subsequently, if the well was originally a production well, the well's extraction method is switched to the condensate gas reservoir extraction method used before unblocking.

[0068] The steps described above are the same as or similar to those in Embodiment 1, and will not be repeated here. Please refer to Embodiment 1 for details.

[0069] The single-well unblocking method for reverse condensate damage in condensate gas reservoirs provided in Embodiment 2 of this invention involves converting the single well into an air injection well, injecting air into the air injection well, igniting it after a first set time, stopping air injection once the current wellhead pressure reaches a set pressure condition, and then shutting the well for a second set time before converting the air injection well into a production well for oil production. If the unblocking is deemed successful based on the decrease in the current wellhead pressure and / or the decrease in oil production of the production well, nitrogen is injected into the production well to extinguish the fire. The single well with reverse condensate damage around the wellbore is first used as an air injection well, where air is injected and ignited, and then converted into a production well to extract the unburned reverse condensate oil blocking the wellbore. This method not only relieves the reverse condensate damage around the wellbore but also extracts most of the unburned reverse condensate oil blocking the wellbore. Furthermore, it has a wide unblocking range, capable of relieving all reverse condensate damage extending around the wellbore.

[0070] In some embodiments, it is determined whether the anti-condensation damage distribution range of the current production well is less than the set allowable damage range; if not, the air injection volume is determined according to the anti-condensation damage distribution range of the current production well, the current production well is changed to an air injection well, air is injected into the current air injection well according to the currently determined air injection volume, ignition is performed in the air injection well when the first set time is reached, the air injection is stopped when the current wellhead pressure reaches the set pressure condition, the well is shut down for a second set time, and the current air injection well is changed to a production well for oil production; if the unblocking is determined to be successful according to the decrease in the current wellhead pressure and / or the decrease in the oil production of the current production well, nitrogen is injected into the production well for fire extinguishing; return to execute the determination of whether the anti-condensation damage distribution range of the current production well is less than the set allowable damage range.

[0071] The damage caused by reverse condensation can be completely resolved by switching between single-well air injection and production circulation.

[0072] Example 3

[0073] This invention provides a specific implementation of a single-well unblocking method for reverse condensation damage in condensate gas reservoirs, using a condensate gas reservoir that has been undergoing depletion-driven development. As formation pressure decreases, reverse condensation becomes significant, resulting in severe reservoir damage. 30% of the wells are in low-production or shut-down states. To restore the reservoir's effective permeability, air injection is implemented for unblocking. This condensate gas reservoir has a burial depth of 3000–3400 m, an original formation pressure of 37 MPa, a formation temperature of 78.5 °C, a porosity of 14.3%, a reservoir permeability of 26.3 mD, and a square well pattern with a well spacing of 200 m.

[0074] The specific implementation process of single-well unblocking is as follows: Figure 3 As shown, it includes the following steps:

[0075] Step S31: Determine the degree and extent of damage caused by anti-condensation, and determine the amount of air injected.

[0076] Through dynamic analysis and reservoir numerical simulation, the analysis results are as follows: the effective permeability of the reservoir has decreased to about 0.5-2 mD; the reverse condensation damage near the production well is severe, and in the plane, it is concentrated in the range of about 25m-40m of the production wellbore, with an average radius of 30m; in the vertical direction, it is about 2.7m-6m, with an average distribution height of 4m.

[0077] Based on the well spacing, controlled area, and calculated reverse condensation range, the optimal air injection rate is calculated to be 9200 Nm³. 3 / d.

[0078] Step S32: Shut down the production well and switch to an air injection well.

[0079] Step S32 is a pretreatment step before air injection. After shutting down the well, the accumulated liquid in the well cavity of the production well is removed, and the air injection pipeline is connected to convert it into an air injection well.

[0080] Step S33: Inject air into the air injection well according to the determined air injection volume, and ignite in the air injection well when the first set time is reached.

[0081] Step S34: Once the current wellhead pressure reaches the set pressure condition, stop the air injection and shut the well for the second set time.

[0082] After 15 days of continuous air injection, the air injection was stopped. At this point, the air slug injected into the reservoir was 138,000 Nm. 3 Shut down the air injection well and shut it off.

[0083] Step S35: Convert the air injection well into a production well for oil production.

[0084] After 5 days of well shut-in, the well was opened for production. The gas production monitoring results are as follows: oxygen content 0.5%, CO2 content 14%, oil production 6.2-12.5 t / d per day, with an average daily oil production of 8 t / d.

[0085] Step S36: If the unblocking is successful based on the decrease in the current wellhead pressure and / or the decrease in oil production of the production well, inject nitrogen into the production well to extinguish the fire.

[0086] After stabilizing production for about 120 days, the oil production began to drop significantly, to only 0.2 to 0.5 t / d. It can be judged that the anti-condensate oil that caused the blockage near the single well has been basically removed, the reservoir has returned to its original level, and the blockage has been successfully cleared.

[0087] Step S37: After nitrogen extinguishing, shut in the well and switch the production method to condensate gas reservoir production method.

[0088] Well shut-in operation. Subsequently, the production method was switched to the condensate gas reservoir production method before unblocking, and the well was once again used as a production well for natural gas production.

[0089] During the unblocking process, approximately 960 tons of anti-condensate oil were recovered. Based on a cost of 2,400 yuan per ton of oil, the economic benefit was 2.3 million yuan. After restoring the original condensate gas reservoir production method, the production well output increased to 1.5 to 2.2 times the original level. Through dynamic analysis and reservoir numerical simulation calculations, the effective permeability of the reservoir was calculated to be equivalent to 23.0 MD, with a recovery level of 87%. The production well maintained high production for 18 months, and the natural gas recovery rate increased by 11.8% compared to before the unblocking operation.

[0090] Statistics show that in this method, the anti-condensate oil used as fuel accounts for only about 5-10%, and most of the remaining anti-condensate oil clogging the wellbore can be extracted with a recovery rate as high as 85-90%, minimizing the loss of anti-condensate oil and resulting in significant economic benefits.

[0091] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0092] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0093] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A method for unblocking well groups suffering from anti-condensation damage in condensate gas reservoirs, characterized in that, include: Based on the distribution range of anti-condensation damage in light oil condensate gas reservoirs, the air injection rate is determined using the following formula, where the anti-condensation damage distribution range refers to the anti-condensation damage distribution range of the well group: Q air =0.82 Sh in, Q air To determine the daily air injection volume, S This represents the average distribution area of ​​anti-condensation damage in the horizontal direction. h The average height of the longitudinal distribution of anti-condensation damage; The selected wells in the well group are changed to air injection wells. Air is injected into the air injection wells according to the air injection volume. When the first set time is reached, the ignition temperature in the air injection wells is controlled to be above 300°C for ignition. If the unblocking is deemed successful based on the decrease in the current wellhead pressure of the air injection well and / or the decrease in the oil production of the production wells in the well group, the air injection is stopped, and nitrogen is injected into the air injection well to extinguish the fire.

2. The method as described in claim 1, characterized in that, After ignition in the air injection well, the process also includes: Monitor whether the CO2 content in the gas produced by the production wells in the well group reaches the set content threshold. If so, ignition is confirmed to be successful; If not, repeat the ignition process in the air injection well until the CO2 content in the gas produced by the production well in the well group reaches the set content threshold.

3. The method as described in claim 2, characterized in that, The set content threshold is 12%.

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