A multi-stage adjustable layered gas injection quantitative regulation and control method

Abstract

The present application belongs to the field of oilfield gas injection development, and discloses a multi-stage adjustable separate layer gas injection quantitative control method which can realize precise adjustment and control of separate layer gas injection. The multi-stage adjustable separate layer gas injection quantitative control method comprises the following steps: step S1: before the multi-stage adjustable injection device is put into the well, the size of the gas nozzle of the multi-stage adjustable injection device is quantitatively calculated according to the injection allocation range and the gas absorption capacity data of each gas injection layer; step S2: the gas nozzle is processed and customized according to step S1; step S3: the multi-stage adjustable separate layer gas injection device is connected, assembled and put into the well with the hydraulic pipeline, the interlayer packer and the wellhead through sealing, and the ground hydraulic controller is connected; step S4: during the separate layer gas injection process, the injection allocation device is adjusted to the size of the gas nozzle which meets the injection allocation requirement according to the gas absorption capacity test data and the gas nozzle loss chart; and step S5: after the adjustment, the actual gas injection amount of each layer is calculated and interpreted according to the gas absorption capacity test data.

Description

Technical Field

[0001] This invention relates to the field of oilfield gas injection development and discloses a multi-level adjustable stratified gas injection quantitative control method. Background Technology

[0002] Gas injection development can significantly improve reservoir recovery, especially for low-permeability reservoirs. Pilot gas injection development trials have been conducted in some offshore oilfields in China. However, for multi-layered reservoirs with significant differences in inter-layer properties, indiscriminate gas injection can lead to gas channeling, affecting the development efficiency and damaging production facilities such as ESPs (Electric Submersible Pumps). Therefore, layered gas injection and refined development play a crucial role in improving oilfield recovery.

[0003] The existing gas injection development method has the following main shortcomings:

[0004] Layered gas injection control requires wireline operation to retrieve and deploy gas nozzles, which has low measurement and adjustment efficiency and high operating costs. Offshore oilfield platforms have limited operating space, and wireline operation to replace gas nozzles occupies the wellhead and affects the operation of other wells. Wireline operation is only suitable for gas injection wells with an inclination of less than 65°, and is not suitable for wells with high inclination or horizontal wells with segmented gas injection.

[0005] The nozzles used in stratified gas injection are of fixed size, resulting in poor matching with the reservoir injection volume. Adjustment is generally done in two ways: one is real-time adjustment based on downhole flow rate testing. However, current downhole stratified flow rate testing technology for gas wells is not yet mature, and a single testing method is insufficient to meet the needs of offshore oilfield gas injection wells with a wide flow range (10). 3 ~10 5 One method involves allocating gas volume roughly based on a single factor such as the gas distribution volume of each layer or formation pressure (Nm3 / d). However, downhole gas injection is highly sensitive to changes in temperature and pressure, resulting in insufficient accuracy in gas distribution. Similarly, obtaining the actual gas injection volume after layered injection control also suffers from the problem of unreliable testing accuracy. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a multi-level adjustable stratified gas injection quantitative control method, which can achieve precise adjustment and control of stratified gas injection.

[0007] The multi-stage adjustable layered gas injection quantitative control method according to the present invention includes the following steps: Step S1: Before the multi-stage adjustable injector is inserted into the well, the size of the multi-stage adjustable nozzle of the injector is quantitatively calculated based on the injection volume range and gas intake capacity data of each injection layer; Step S2: The nozzle is processed and customized according to Step S1; Step S3: The multi-stage adjustable layered gas injection injector is connected, assembled, and inserted into the well via hydraulic lines, interlayer packers, and wellhead penetration seals, and connected to the surface hydraulic controller; Step S4: During the layered gas injection process, the injector is adjusted to the nozzle size that meets the injection volume requirements based on the gas intake capacity test data of each layer and the nozzle wear chart; Step S5: After adjustment, the actual gas injection volume of each layer is calculated and interpreted based on the gas intake capacity test data of each layer.

[0008] Further, step S1 includes the following steps: Step S101: Based on reservoir static data and injection-production dynamic data, give the extreme values ​​of the gas injection rate for each gas injection layer. The extreme values ​​of the gas injection rate include the maximum gas injection rate q for each layer. imax and minimum gas injection volume q imin Step S102: Obtain the air intake capacity indicator curve for each injection layer; Step S103: Combine to obtain all injection operating regimes with the greatest differences between injection layers; Step S104: Determine the pressure after the nozzle and the pressure before the nozzle of each injection layer dispenser under all injection regimes; Step S105: Determine the equivalent diameter range of the nozzle opening of each injection layer dispenser; Step S106: Determine the equivalent diameter of each position of the nozzle opening of each injection layer dispenser.

[0009] Further, in step S102, the gas intake capacity indicator curves of each injection layer are obtained through on-site testing, and the relationship of the obtained gas intake capacity indicator curves is as follows:

[0010] q i =f(p chei ,T i (Equation 1)

[0011] In the formula, q i p represents the gas injection volume for each layer. chei T represents the gas injection pressure for each formation. i The gas injection temperature for each layer;

[0012] Alternatively, the gas intake capacity indicator curves for each injection layer can be calculated using reservoir data, and the calculation formula is as follows:

[0013]

[0014] In the formula, k i h i This refers to the formation coefficient of the gas injection layer. Z is a parameter characterizing the viscosity and compressibility factor of the gas in the relationship between the pseudo-pressure function difference of the injection layer and the square difference of the injection pressure. aT is the gas compressibility factor under standard conditions. a p represents the absolute temperature of the gas under standard conditions. a For standard condition pressure, T i p represents the gas injection temperature for each layer. ri The starting pressure of the gas injection layer, r L For the distance between injection and production wells, r w Where is the radius of the wellbore.

[0015] Further, in step S103, the method for combining all the gas injection operating regimes with the greatest interlayer differences is as follows: the maximum and minimum gas injection volumes of each gas injection layer are combined to form 2 N This type of gas injection system is denoted as

[0016]

[0017] 2 N Two types of gas injection systems correspond to 2 N The total gas injection volume is denoted as

[0018]

[0019] Further, in step S104, 2 N The pressure after the nozzle of the injector corresponding to each injection regime is calculated according to Equation 1 or Equation 2:

[0020]

[0021] 2 N The pressure before the injector nozzle corresponding to each gas injection regime is calculated using a gas injection wellbore temperature and pressure model, or calculated from a relationship obtained through testing, denoted as...

[0022]

[0023] Furthermore, in step S105, combining equations 5 and 6 and the nozzle pressure loss model, 2 is obtained. N The equivalent diameter of the valve is denoted as...

[0024]

[0025] Select the minimum value d in Equation 7 imin The maximum value d is selected as the minimum equivalent diameter of the gas injection nozzle in this gas injection layer. imax As the second largest equivalent diameter of the gas injection nozzle in this gas injection layer, the maximum equivalent diameter of the gas injection nozzle is determined to be equal to the minimum inner diameter of the injector, so as to meet the needs of implementing large-volume injection measures in the gas injection layer.

[0026] Furthermore, the valve pressure loss model was determined based on the following formula through ground testing or field testing:

[0027] when hour,

[0028] when hour,

[0029] In the formula, k is the gas adiabatic coefficient, q isc γ is the gas flow rate through the nozzle under standard conditions. g T represents the relative density of the gas. chfi Z represents the temperature of the gas in front of the mouth. chfi C is the pre-oral gas deviation factor. d The coefficients related to the Reynolds number and the shape, number, and arrangement of the nozzles are obtained through ground test experiments or field tests. When the gas flow is in a subcritical state during stratified gas injection in offshore oil fields, Equation 9 is used as the calculation formula for the nozzle pressure loss model.

[0030] Further, in step S106, d imin As the minimum equivalent diameter of the i-th layer dispenser, d imax The second largest equivalent diameter of the i-th level dispenser is used as the minimum inner diameter of the dispenser, which is also used as the maximum equivalent diameter of the i-th level dispenser. The equivalent diameters of the other levels of the n-level adjustable dispenser are... Based on the equivalent diameter and nozzle distribution of each gear level, design the number of holes and the diameter of each nozzle level.

[0031] Further, step S4 includes the following steps:

[0032] Step S401: Test the single-layer gas intake capacity data of the current time-series stratified gas injection well;

[0033] Step S402: Calculate the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions. Specifically, based on the test data from step S401 and combined with the gas injection wellbore temperature and pressure model, the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions is calculated and denoted as...

[0034] q i =f(p chei ,T i (Equation 10)

[0035] The pressure behind the nozzle corresponding to the injection volume is calculated using Equation 10;

[0036] Step S403: Based on the principle that the injection pressure at the wellhead of each layer is consistent during stratified gas injection, a stratified gas injection pressure model is established, and the calculation formula is as follows:

[0037] p tb =p che1 +Δpch1 +p f1 +…=p che2 +Δp ch2 +p f2 +…=…=p cheN +Δp chN +p fN +… (Equation 11)

[0038] In the formula, except for Δp chi All others are known or obtainable variables;

[0039] Step S404: Select the dispenser setting for each gas injection layer. For the layer with the highest injection pressure corresponding to the dispensed volume, select the maximum dispenser setting and calculate Δp for that layer based on the nozzle pressure loss model. chi Δp for other layers can be obtained according to Equation 11. chi Then, based on the nozzle pressure loss model, the equivalent diameter and setting of the dispenser that meets the dispensing amount for all other layers are obtained;

[0040] Step S405: Adjust the downhole injector settings using the surface controller, specifically adjusting the settings of each downhole injector layer to the settings calculated in step S404, and adjusting the wellhead gas injection flow rate to the total well injection volume Q. tot At this time, the injection pressure is P and the injection temperature is T.

[0041] Further, step S5 includes the following steps:

[0042] Step S501: Calculate the pressure and temperature before the nozzle of the first gas injection layer distributor. Specifically, based on the wellhead gas injection pressure, temperature, and flow rate, and combined with the gas injection wellbore temperature and pressure model, calculate the pressure p1 and temperature T1 before the nozzle of the first gas injection layer distributor.

[0043] Step S502: Calculate the gas injection flow rate of the first gas injection layer. For the current nozzle position of the first gas injection device, combine Equations 9 and 10 to obtain the gas injection flow rate q1 of the first gas injection layer.

[0044] Step S503: Calculate the gas injection flow rate of other gas injection layers, wherein steps S501 and S502 are repeated to calculate the gas injection flow rates q2, q3, ..., q of the second, third, ..., Nth gas injection layers. N ,remember

[0045] Step S504: Comprehensive splitting to eliminate calculation errors, wherein the actual gas injection flow rate of each layer is:

[0046]

[0047] Step S505: Calculate the gas injection volume of each layer under other injection pressures and temperatures. If the wellhead is injected with gas at pressure P′ and temperature T′, repeat steps S501 to S504 to obtain the gas injection volume of each layer under pressure P′ and temperature T′.

[0048] Compared with existing technologies, the multi-level adjustable layered gas injection quantitative control method of the present invention achieves precise quantitative layered gas injection throughout the entire process, from tool nozzle opening design, wellbore distribution, and distribution interpretation. It can control the nozzle opening of the downhole distributor from the surface and can also open or close each injection layer without the need for wireline work to replace nozzles, and does not occupy the wellhead working space of the offshore platform. The multi-level adjustable nozzles are prefabricated in the distributor, and the nozzle opening size is precisely matched to the design according to the distribution volume to avoid the situation where the distribution volume of each layer is not met. Based on the surface gas intake capacity test data, the nozzle opening can be precisely adjusted to meet the distribution volume, and the layered gas injection volume during actual gas injection of each layer can be obtained. No additional downhole testing work is required, and no downhole testing equipment needs to be installed, which meets the needs of fine gas injection development of oil reservoirs. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the multi-level adjustable stratified gas injection quantitative control method according to an embodiment of the present invention.

[0050] Figure 2 for Figure 1 The flowchart of step S1 is shown below;

[0051] Figure 3 for Figure 1 The flowchart of step S4 is shown below;

[0052] Figure 4 for Figure 1 The flowchart of step S5 is shown below;

[0053] Figure 5 A schematic diagram showing the connection between the multi-stage adjustable stratified gas injection string and the ground controller;

[0054] Figure 6 A schematic diagram of the structure of a multi-stage adjustable air nozzle for a dispensing device;

[0055] Figure 7 for Figure 6 The diagram shows a planar unfolded schematic of the air nozzle. Detailed Implementation

[0056] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0057] Figure 1 A schematic flowchart of a multi-level adjustable stratified gas injection quantitative control method 100 according to an embodiment of the present invention is shown. Figure 1 As shown, the multi-stage adjustable layered gas injection quantitative control method 100 may include the following steps: Step S1: Before the multi-stage adjustable injector is inserted into the well, the size of the multi-stage adjustable nozzle of the injector is quantitatively calculated based on the injection volume range and gas intake capacity data of each injection layer; Step S2: The nozzle is customized according to Step S1; Step S3: as shown in the figure. Figure 5 As shown, the multi-stage adjustable stratified gas injection dispenser 4 is assembled with the hydraulic control line 3, the interlayer packer 5, and the wellhead through-sealing connection 2, and then inserted into the well, and connected to the surface hydraulic controller 1; Step S4: During the stratified gas injection process, the dispenser is adjusted to the gas nozzle size that meets the injection volume requirements based on the gas intake capacity test data of each layer and the gas nozzle loss chart (also known as the gas nozzle pressure loss model); Step S5: After adjustment, the actual gas injection volume of each layer is calculated and interpreted based on the gas intake capacity test data of each layer.

[0058] The multi-level adjustable layered gas injection quantitative control method 100 of this invention can achieve precise customized processing of gas nozzles by matching the nozzle opening with the injection volume range and the formation gas intake capacity. At the same time, it makes full use of the advantages of the adjustable surface process. Based on the surface gas intake capacity test data, the nozzle opening can be precisely adjusted to meet the injection volume, and the layered gas injection volume during actual gas injection in each layer can be obtained. No additional downhole testing work is required, and no downhole testing equipment needs to be installed, which meets the needs of fine gas injection development in oil reservoirs.

[0059] According to the present invention, in such Figure 2 In the preferred embodiment shown, step S1 may include the following steps: Step S101: Based on reservoir static data and injection-production dynamic data, give the extreme values ​​of the injection volume for each gas injection layer, where the extreme values ​​of the injection volume include the maximum gas injection volume q for each layer. imax and minimum gas injection volume q imin Step S102: Obtain the air intake capacity indicator curve for each injection layer; Step S103: Combine to obtain all injection operating regimes with the greatest differences between injection layers; Step S104: Determine the pressure after the nozzle and the pressure before the nozzle of each injection layer dispenser under all injection regimes; Step S105: Determine the equivalent diameter range of the nozzle opening of each injection layer dispenser; Step S106: Determine the equivalent diameter of each position of the nozzle opening of each injection layer dispenser.

[0060] Further, in step S102, the gas intake capacity indicator curves of each injection layer are obtained through on-site testing, and the relationship of the obtained gas intake capacity indicator curves is as follows:

[0061] q i =f(p chei ,T i (Equation 1)

[0062] In the formula, q i p represents the gas injection volume for each layer. cheiT represents the gas injection pressure for each formation. i The gas injection temperature for each layer;

[0063] Alternatively, the gas intake capacity indicator curves for each injection layer can be calculated using reservoir data, and the calculation formula is as follows:

[0064]

[0065] In the formula, k i h i This refers to the formation coefficient of the gas injection layer. Z is a parameter characterizing the viscosity and compressibility factor of the gas in the relationship between the pseudo-pressure function difference of the injection layer and the square difference of the injection pressure. a T is the gas compressibility factor under standard conditions. a p is the absolute temperature of the gas under standard conditions. a For standard condition pressure, T i p represents the gas injection temperature for each layer. ri The starting pressure of the gas injection layer, r L For the distance between injection and production wells, r w Where is the radius of the wellbore.

[0066] Further, in step S103, the method for combining all the gas injection operating regimes with the greatest interlayer differences is as follows: the maximum and minimum gas injection volumes of each gas injection layer are combined to form 2 N This type of gas injection system is denoted as

[0067]

[0068] 2 N Two types of gas injection systems correspond to 2 N The total gas injection volume is denoted as

[0069]

[0070] Further, in step S104, 2 N The pressure after the nozzle of the injector corresponding to each injection regime is calculated according to Equation 1 or Equation 2:

[0071]

[0072] 2 N The pressure before the injector nozzle corresponding to each gas injection regime is calculated using a gas injection wellbore temperature and pressure model, or calculated from a relationship obtained through testing, denoted as...

[0073]

[0074] Furthermore, in step S105, combining equations 5 and 6 with the nozzle pressure loss model, 2 is obtained. N The equivalent diameter of the valve is denoted as...

[0075]

[0076] Select the minimum value d in Equation 7 imin The maximum value d is selected as the minimum equivalent diameter of the gas injection nozzle in this gas injection layer. imax As the second largest equivalent diameter of the gas injection nozzle in this gas injection layer, the maximum equivalent diameter of the gas injection nozzle is determined to be equal to the minimum inner diameter of the injector, so as to meet the needs of implementing large-volume injection measures in the gas injection layer.

[0077] Preferably, the nozzle pressure loss model can be determined based on the following formula through ground testing or field testing:

[0078] when hour,

[0079] when hour,

[0080] In the formula, k is the gas adiabatic coefficient, q isc γ is the gas flow rate through the nozzle under standard conditions. g T is the relative density of the gas. chfi Z represents the temperature of the gas in front of the mouth. chfi C is the pre-oral gas deviation factor. d The coefficients related to the Reynolds number and the shape, number, and arrangement of the nozzles are obtained through ground test experiments or field tests. When the gas flow is in a subcritical state during stratified gas injection in offshore oil fields, Equation 9 is used as the calculation formula for the nozzle pressure loss model.

[0081] Further, in step S106, d imin As the minimum equivalent diameter of the i-th layer dispenser, d imax The second largest equivalent diameter of the i-th level dispenser is used as the minimum inner diameter of the dispenser, which is also used as the maximum equivalent diameter of the i-th level dispenser. The equivalent diameters of the other levels of the n-level adjustable dispenser are... Based on the equivalent diameter and nozzle distribution of each gear level, design the number of holes and the diameter of each nozzle level.

[0082] According to the present invention, in step S2, as Figure 5 As shown, one end of the hydraulic control line 3 is connected to the surface hydraulic controller 1, and the other end is connected to the downhole injector 4. The hydraulic control line 3 passes through the wellhead crossing seal 2 and the interlayer packer 5 from top to bottom. The wellhead crossing seal 2 and the interlayer packer 5 can achieve sealing at each crossing node. The surface hydraulic controller 1 provides hydraulic power to drive the hydraulic oil in the hydraulic control line 3 and transmit the pressure to the hydraulic chamber of the downhole injector 4. The pressure change in the hydraulic chamber pushes the moving parts to slide to change the opening of the air nozzle.

[0083] like Figure 6 and Figure 7 As shown, the central tube 41 of the dispenser 4 has a series of round holes of different sizes, i.e., air nozzles. The air nozzles are distributed at 90° in the circumference and in multiple rows in the axial direction. They can slide to different positions through the internal bushing (not shown in the figure) to change the number of rows of air nozzles blocked, thereby changing the number of air nozzles that are open.

[0084] According to the present invention, such as Figure 3 As shown, step S4 may include the following steps: Step S401: Test the single-layer gas intake capacity data of the current time-layered gas injection well; including using the surface hydraulic controller to close other gas injection layers and only open the test layer, and test the relationship between the gas injection volume and the change of the wellhead injection pressure.

[0085] Step S402: Calculate the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions. Specifically, based on the test data from step S401 and combined with the gas injection wellbore temperature and pressure model, the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions is calculated and denoted as...

[0086] q i =f(p chei ,T i (Equation 10)

[0087] The pressure behind the nozzle corresponding to the injection volume is calculated using Equation 10.

[0088] Step S403: Based on the principle that the injection pressure at the wellhead of each layer is consistent during stratified gas injection, a stratified gas injection pressure model is established, and the calculation formula is as follows:

[0089] p tb =p che1 +Δp ch1 +p f1 +…=p che2 +Δp ch2 +p f2 +…=…=p cheN +Δp chN +p fN +… (Equation 11)

[0090] In the formula, except for Δp chi All others are known or obtainable variables.

[0091] Step S404: Select the dispenser setting for each gas injection layer. For the layer with the highest injection pressure corresponding to the dispensed volume, select the maximum dispenser setting and calculate Δp for that layer based on the nozzle pressure loss model. chi Δp for other layers can be obtained according to Equation 11. chiThen, based on the nozzle pressure loss model, the equivalent diameter and setting of the dispenser that meets the dispensing volume for all other layers are obtained.

[0092] Step S405: Adjust the downhole injector settings using the surface controller, specifically adjusting the settings of each downhole injector layer to the settings calculated in step S404, and adjusting the wellhead gas injection flow rate to the total well injection volume Q. tot At this time, the injection pressure is P and the injection temperature is T.

[0093] According to the present invention, such as Figure 4 As shown, step S5 includes the following steps: Step S501: Calculate the pressure and temperature in front of the nozzle of the first gas injection layer distributor, wherein, based on the wellhead gas injection pressure, temperature and flow rate, and combined with the gas injection wellbore temperature and pressure model, calculate the pressure p1 and temperature T1 in front of the nozzle of the first gas injection layer distributor.

[0094] Step S502: Calculate the gas injection flow rate of the first gas injection layer. For the current nozzle position of the first layer injector, combine Equations 9 and 10 to obtain the gas injection flow rate q1 of the first gas injection layer.

[0095] Step S503: Calculate the gas injection flow rate of other gas injection layers, wherein steps S501 and S502 are repeated to calculate the gas injection flow rates q2, q3, ..., q of the second, third, ..., Nth gas injection layers. N ,remember

[0096] Step S504: Comprehensive splitting to eliminate calculation errors, wherein the actual gas injection flow rate of each layer is:

[0097]

[0098] Step S505: Calculate the gas injection volume of each layer under other injection pressures and temperatures. If the wellhead is injected with gas at pressure P′ and temperature T′, repeat steps S501 to S504 to obtain the gas injection volume of each layer under pressure P′ and temperature T′.

[0099] The multi-level adjustable layered gas injection quantitative control method 100 of this invention can adjust the size of the gas nozzle of the downhole injector in real time on the ground. From the design of the gas nozzle size before entering the well to the control of the gas nozzle size and the interpretation of the layered gas injection volume in the well, the entire process is carried out through quantitative calculation, thereby achieving precise matching of the gas injection volume of the injection layer.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. 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 or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-level adjustable stratified gas injection quantitative control method, characterized in that, Includes the following steps: Step S1: Before the multi-stage adjustable injector is inserted into the well, the size of the multi-stage adjustable nozzle of the injector is quantitatively calculated based on the injection volume range and gas intake capacity data of each injection layer. Step S2: Process and customize the air nozzle according to step S1; Step S3: Connect, assemble, and insert the multi-stage adjustable stratified gas injection device into the hydraulic pipeline, interlayer packer, and wellhead crossing seal, and connect it to the surface hydraulic controller; Step S4: During the layered air injection process, adjust the injector to the nozzle size that meets the injection volume requirements based on the air intake capacity test data of each layer and the nozzle wear diagram. Step S5: After adjustment, calculate and interpret the actual air volume of each layer based on the air intake capacity test data of each layer.

2. The multi-level adjustable stratified gas injection quantitative control method according to claim 1, characterized in that, Step S1 includes the following steps: Step S101: Based on reservoir static data and injection-production dynamic data, provide the extreme values ​​of gas injection rates for each gas injection layer. The extreme values ​​of gas injection rates include the maximum gas injection rate for each layer. and minimum gas injection volume ; Step S102: Obtain the gas intake capacity indicator curve for each gas injection layer; Step S103: Combine all the gas injection operating regimes with the greatest difference between the gas injection layers; Step S104: Determine the post-nozzle pressure and pre-nozzle pressure of each gas injection layer dispenser under all injection regimes; Step S105: Determine the equivalent diameter range of the nozzle opening of each gas injection layer; Step S106: Determine the equivalent diameter of each position of the nozzle opening of the gas injector in each gas injection layer.

3. The multi-stage adjustable stratified gas injection quantitative control method according to claim 2, characterized in that, In step S102, the gas intake capacity indicator curves of each gas injection layer are obtained through on-site testing, and the relationship of the obtained gas intake capacity indicator curves is as follows: (Equation 1) In the formula, For the gas injection volume of each layer, Injecting gas pressure into each formation, The gas injection temperature for each layer; Alternatively, the gas intake capacity indicator curves of each of the aforementioned gas injection layers can be calculated using reservoir data, and the calculation formula is as follows: (Equation 2) In the formula, k i h i This refers to the formation coefficient of the gas injection layer. It is a parameter characterizing the viscosity and compressibility factor of the gas in the relationship between the pseudo-pressure function difference of the injection layer and the square difference of the injection pressure. The gas compressibility factor under standard conditions. The absolute temperature of the gas under standard conditions. For standard condition pressure, The gas injection temperature for each layer, The starting pressure for the gas injection layer, For injection and production well spacing, Where is the radius of the wellbore.

4. The multi-level adjustable stratified gas injection quantitative control method according to claim 3, characterized in that, In step S103, the method for combining all gas injection operating regimes with the greatest interlayer differences is as follows: the maximum and minimum gas injection volumes of each gas injection layer are combined to form... This type of gas injection system is denoted as (Equation 3) Type of gas injection system corresponding The total gas injection volume is denoted as (Equation 4).

5. The multi-stage adjustable stratified gas injection quantitative control method according to claim 4, characterized in that, In step S104, The pressure after the nozzle of the injector corresponding to the injection regime is calculated according to Equation 1 or Equation 2: (Equation 5) The pressure before the injector nozzle corresponding to each gas injection regime is calculated using a gas injection wellbore temperature and pressure model, or calculated from a relationship obtained through testing, denoted as... (Formula 6).

6. The multi-stage adjustable stratified gas injection quantitative control method according to claim 5, characterized in that, In step S105, by combining Equation 5, Equation 6, and the air nozzle pressure loss model, the following is obtained: The equivalent diameter of the valve is denoted as... (Equation 7) Select the minimum value in Equation 7 The maximum value is selected as the minimum equivalent diameter of the gas injection nozzle for this gas injection layer. As the second largest equivalent diameter of the gas injection nozzle in this gas injection layer, the maximum equivalent diameter of the gas injection nozzle is determined to be equal to the minimum inner diameter of the injector, so as to meet the needs of implementing large-volume injection measures in the gas injection layer.

7. The multi-stage adjustable stratified gas injection quantitative control method according to claim 6, characterized in that, The valve pressure loss model was determined based on the following formula through ground testing or field testing: when hour, (Equation 8); when hour, (Equation 9) In the formula, The adiabatic coefficient of the gas. This refers to the gas flow rate through the valve under standard conditions. The relative density of the gas, The temperature of the gas in front of the mouth. The gas deviation factor in front of the mouth, The coefficients related to the Reynolds number and the shape, number, and arrangement of the nozzles are obtained through ground test experiments or field tests. When the gas flow is in a subcritical state during stratified gas injection in offshore oil fields, Equation 9 is used as the calculation formula for the nozzle pressure loss model.

8. The multi-level adjustable stratified gas injection quantitative control method according to claim 7, characterized in that, In step S106, As the minimum equivalent diameter of the i-th layer dispenser. The second largest equivalent diameter of the i-th level dispenser is used as the minimum inner diameter of the dispenser, which is also used as the maximum equivalent diameter of the i-th level dispenser. The equivalent diameters of the other levels of the n-level adjustable dispenser are... , , ..., Based on the equivalent diameter and nozzle distribution of each gear level, the number of holes and the diameter of each nozzle level are designed.

9. The multi-level adjustable stratified gas injection quantitative control method according to claim 8, characterized in that, Step S4 includes the following steps: Step S401: Test the single-layer gas intake capacity data of the current time-series stratified gas injection well; Step S402: Calculate the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions. Specifically, based on the test data from step S401 and combined with the gas injection wellbore temperature and pressure model, the relationship between the injection volume and the pressure after the nozzle under downhole temperature conditions is calculated and denoted as... (Equation 10) The post-orifice pressure corresponding to the dispensing volume is calculated using Equation 10. Step S403: Based on the principle that the injection pressure at the wellhead of each layer is consistent during stratified gas injection, a stratified gas injection pressure model is established, and the calculation formula is as follows: (Equation 11) In the formula, p tb Inject pressure into the wellhead of each layer; p represents the difference between the pressure in front of and behind the mouth; fi This refers to the pressure loss between the wellhead and the injector nozzle; where, except for All others are known or obtainable variables; Step S404: Select the dispenser setting for each injection layer. For the layer with the highest injection pressure corresponding to the dispensed volume, select the highest dispenser setting. Calculate the pressure loss of that layer based on the nozzle pressure loss model. Other layers are obtained according to Equation 11. Then, based on the nozzle pressure loss model, the equivalent diameter and setting of the dispenser that meets the dispensing amount for all other layers are obtained; Step S405: Adjust the downhole injector settings using the surface controller, wherein the settings of each downhole injector layer are adjusted to the settings calculated in step S404, and the wellhead gas injection flow rate is adjusted to the total injection volume for the entire well. At this time, the injection pressure is P and the injection temperature is T.

10. The multi-level adjustable stratified gas injection quantitative control method according to claim 9, characterized in that, Step S5 includes the following steps: Step S501: Calculate the pressure and temperature before the nozzle of the first gas injection layer distributor. Specifically, based on the wellhead gas injection pressure, temperature, and flow rate, and combined with the gas injection wellbore temperature and pressure model, calculate the pressure p1 and temperature T1 before the nozzle of the first gas injection layer distributor. Step S502: Calculate the gas injection flow rate of the first gas injection layer. For the current nozzle setting of the first gas injection device, combine Equations 9 and 10 to obtain the gas injection flow rate of the first gas injection layer. ; Step S503: Calculate the gas injection flow rate of other gas injection layers, wherein steps S501 and S502 are repeated to calculate the gas injection flow rate of the second gas injection layer, the third gas injection layer, ..., the Nth gas injection layer. , ... ,remember ; Step S504: Comprehensive splitting to eliminate calculation errors, wherein the actual gas injection flow rate of each layer is: (Equation 12) In the formula, Q is the actual total gas injection flow rate; Step S505: Calculate the gas injection volume of each layer under other injection pressures and temperatures. If the wellhead is injected with gas at pressure P′ and temperature T′, repeat steps S501 to S504 to obtain the gas injection volume of each layer under pressure P′ and temperature T′.

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