Calculation method and device for layered steam injection allocation of steam flooding well, medium and equipment

Abstract

The invention relates to a calculation method and device for layered steam injection allocation of a steam flooding well, a medium and equipment, and the method comprises the steps: adjusting wellhead injection pressure or injection displacement, recording data, and forming a wellhead steam suction indication curve; a point is selected on a wellhead steam suction indication curve, and the pressure in front of a valve hole at the position of the current injection allocation valve is calculated through wellbore pressure loss; calculating the steam dryness of the steam from the wellhead to the point; calculating the throttling loss of the valve hole of the injection allocation valve in combination with the steam mass flow on the ground; the formation suction pressure of the current layer is obtained by subtracting the throttling loss of the valve hole of the injection allocation valve from the front pressure of the valve hole; taking a plurality of injection pressure points and injection displacements to obtain a steam absorption indication curve of the stratum; other stratums of the layered steam injection well are selected again, and stratum steam absorption indication curves of the other stratums are obtained; according to the stratum steam absorption indication curve of the whole stratum of the layered steam injection well, the limit value of wellhead injection pressure is determined; and determining the upstream pressure of each layer by referring to the limit value, and determining the size of a valve hole required to be configured by the injection allocation valve.

Description

Technical Field

[0001] The invention relates to a calculation method, device, medium and equipment for stratified steam injection and allocation in a steam drive well, belonging to the technical field of oil production engineering. Background Art

[0002] Steam drive production is a connection technology for further improving crude oil recovery after steam huff-and-puff production of heavy oil reservoirs. Steam drive can provide higher crude oil recovery. For multi-layer heavy oil reservoirs, due to differences in formation properties, injection and production of liquids during the huff-and-puff stage further exacerbate the single-layer advance and uneven utilization of each layer. In order to further improve the steam drive thermal recovery effect, it is necessary to carry out adjustable process matching and dynamically adjust with the changes in the formation. At present, steam drive matching has only been carried out for the design of pipe strings and tools, and no explanation has been given for the valve hole design of the injection volume and the single-layer injection.

[0003] Steam-driven wells are affected by high temperature and high pressure environments. The injection volume of each layer cannot be measured by tools, and the injection valve cannot be electrically controlled. Mechanical control methods are mainly used. In order to achieve formation injection, the valve hole of the injection valve needs to be adjusted. The lack of calculation method will result in no theoretical basis for valve hole adjustment.

[0004] With the increasing demand for steam drive deployment, it is necessary to adjust the reasonable valve hole formation calculation method according to the differences of each layer, so as to match the efficient deployment technology and improve the deployment efficiency of steam drive wells.

[0005] At present, the steam drive production technology mainly focuses on insulation, parameter monitoring, layered steam injection process string, injection tools, layered injection volume calculation and other aspects, but there is no description of how to configure the valve holes for layered and segmented steam injection so that the steam injection in each section reaches the injection volume. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a calculation method, device, medium and equipment for stratified steam injection allocation in steam-driven wells. The method can be used to make up for the disadvantage that steam-driven wells cannot be accurately tested by testing instruments due to high temperature or well type, so as to make injection allocation.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A calculation method for stratified steam injection allocation in steam drive wells, comprising:

[0009] S1: For stratified steam injection wells where fishing tools are lowered by wireline operation to adjust the valve hole area of ​​each layer or replace the valve core, the wellhead injection pressure or injection displacement is adjusted by adjusting the wellhead valve, and the stable injection state data of at least three points are recorded to form a wellhead steam absorption indication curve;

[0010] S2: Select a point on the wellhead steam suction indication curve with known wellhead injection pressure, steam displacement and steam dryness, and calculate the pressure P before the valve hole at the current injection valve position. f ;

[0011] S3: Calculate the steam dryness from the wellhead to this point;

[0012] S4: Get the pressure P before the valve hole at this point f After calculating the steam quality, the throttling loss ΔP of the injection valve hole is calculated based on the ground steam mass flow rate. m ;

[0013] S5: Using the pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , obtain the formation suction pressure under the corresponding steam injection amount of the current layer;

[0014] S6: repeating steps S1-S5, taking a number of injection pressure points and corresponding injection displacements, and thus obtaining a steam absorption indication curve of the formation;

[0015] S7: reselecting other strata of the stratified steam injection well, repeating steps S1 to S6, and obtaining formation steam absorption indication curves of other strata;

[0016] S8: Obtaining a formation steam absorption indication curve for the entire formation of the stratified steam injection well according to the formation steam absorption indication curve of a certain formation obtained in step S6 and the formation steam absorption indication curves of other formations obtained in step S7;

[0017] S9: Determine the limit value of the wellhead injection pressure according to the formation steam absorption indication curve of the whole formation of the stratified steam injection well;

[0018] S10: Refer to the limit value of the wellhead injection pressure to determine the pressure P before the valve of each layer f , and then according to the pressure P before each valve f Determine the valve hole size required for the injection valve to achieve precise injection.

[0019] The calculation method for steam injection allocation of steam drive wells is preferably as follows: when the injection valve is provided with multiple gear valve holes, the specific steps of adjusting the injection valve to a suitable gear are as follows:

[0020] A1: Knowing the range of steam injection volume for each layer, arrange and combine to find the combination with the largest difference in steam injection volume between layers;

[0021] A2: Calculate the pressure P before the valve of each layer under the combination with the maximum steam injection difference according to the wellhead injection pressure f ;

[0022] A3: Calculate the formation steam absorption pressure based on the formation steam absorption indication curve or formation test data of each layer;

[0023] A4: Use the pressure P before each valve f Subtract the formation steam absorption pressure to calculate the appropriate area of ​​the valve hole;

[0024] A5: Based on the maximum and minimum valve hole areas of each layer calculated according to the difference in steam injection volume, evenly arrange the valve hole areas of other gears according to the appropriate opening gear;

[0025] A6: When starting production, calculate the valve hole area under the corresponding injection amount according to the mixing method of claim 1, so as to adjust the injection valve to the appropriate gear position.

[0026] The calculation method for steam injection allocation in steam-driven wells preferably requires that when the wellhead injection parameters change, flow splitting calculations be performed on each layer downhole to obtain injection volume data for each layer. The specific method is as follows:

[0027] B1: The known wellhead steam injection volume becomes Q c and the injection pressure becomes P c , according to the pressure before the valve P f The total displacement Q is calculated by the calculation formula c Pressure drop ΔP flowing to a certain injection valve f , thus obtaining the valve front pressure P of the injection valve V1 ;

[0028] B2: According to the area of ​​the currently configured valve hole of the injection valve in B1, the throttling loss ΔP of the injection valve hole m The calculation formula is used to calculate the throttling loss ΔP of the current injection valve. m1 , use the valve front pressure P V1 Subtract ΔP m1 The formation steam absorption pressure P of the current layer can be obtained 01 ;

[0029] B3: According to the formation steam absorption index curve or formation steam absorption test data of the injection valve in B1, find the corresponding formation steam absorption pressure P 01 The displacement Q1 is the injection volume allocated to the injection valve layer in B1;

[0030] B4: According to the pressure before the valve P f The calculation formula for calculating Q c -Q1 displacement from the injection valve in B1 to the other injection valve pressure drop, denoted by P V1 Subtract ΔP f1 , you can get the pressure P before the other injection valve 02 ;

[0031] B5: According to the formation steam absorption index curve or formation steam absorption test data of another injection valve, find the corresponding formation steam absorption pressure P01 The displacement Q2 is the injection volume allocated to another injection valve layer;

[0032] B6: Use total displacement Q c Subtract the displacement Q1 allocated to the injection valve layer in B1 and the displacement Q2 allocated to another injection valve layer to obtain the displacement allocated to the third layer.

[0033] The calculation method for steam injection allocation of steam drive wells is preferably that the pressure before the valve hole P in step S2 is f The calculation formula is as follows:

[0034]

[0035] Where P1 is the starting point pressure; the depth increment is dz, and the pressure drop is dP f ρ m is the steam density; G m is the total mass flow rate of steam per unit cross-sectional area; V m V is the apparent velocity of steam; sg is the gas phase apparent (converted) velocity; θ is the angle between the pipe section and the horizontal direction; λ is the flow resistance; D is the inner diameter of the oil pipe; A is the cross-sectional area of ​​the oil pipe.

[0036] In the calculation method for stratified steam injection allocation in steam drive wells, preferably, in step S3, the steam quality of steam from the wellhead to the point is calculated, and the specific formula is as follows:

[0037]

[0038] In the formula, h l is the steam enthalpy; h g is the gas phase enthalpy value; x is the steam quality value; T is the temperature of each point in the wellbore; p is the pressure of each point in the wellbore; h is the steam enthalpy value, and z is the well temperature.

[0039] The calculation method for steam injection allocation of steam drive wells is preferably that the throttling loss ΔP of the injection valve hole in step S4 is m The calculation formula is as follows:

[0040]

[0041] In the formula, G Qm is the steam mass flow rate; is the steam expansion coefficient; C d is the steam flow coefficient; A f is the cross-sectional area of ​​the valve hole; ΔP m is the throttling loss of the injection valve; β is the ratio of the valve hole diameter d to the diameter of the flow channel before the valve.

[0042] A second aspect of the present invention provides a computing device for steam injection allocation in steam drive wells, comprising:

[0043] The first processing unit is used to adjust the wellhead injection pressure or injection displacement by adjusting the wellhead valve for the stratified steam injection well where the fishing tool is lowered by wireline operation to adjust the valve hole area of ​​each layer or replace the valve core, record the stable injection state data of at least three points, and form a wellhead steam absorption indication curve;

[0044] The second processing unit is used to select a point on the wellhead steam suction indication curve with known wellhead injection pressure, steam displacement and steam dryness, and calculate the valve hole front pressure P at the current injection valve position. f ;

[0045] The third processing unit is used to calculate the steam quality of steam from the wellhead to the point;

[0046] The fourth processing unit is used to obtain the pressure P before the valve hole at this point f After calculating the steam quality, the throttling loss ΔP of the injection valve hole is calculated based on the ground steam mass flow rate. m ;

[0047] The fifth processing unit is used to utilize the pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , obtain the formation suction pressure under the corresponding steam injection amount of the current layer;

[0048] The sixth processing unit is used to repeat the steps of the first processing unit to the fifth processing unit, take a number of injection pressure points and corresponding injection displacements, and thus obtain a steam absorption indication curve of the formation;

[0049] The seventh processing unit is to reselect other strata of the stratified steam injection well, repeat the first processing unit to the sixth processing unit, and obtain the formation steam absorption indication curve of other strata;

[0050] An eighth processing unit is used to obtain a formation steam absorption indication curve of the entire formation of the stratified steam injection well according to the formation steam absorption indication curve of a certain formation obtained by the sixth processing unit and the formation steam absorption indication curves of other formations obtained by the seventh processing unit;

[0051] A ninth processing unit, determining a limit value of the wellhead injection pressure according to a formation steam absorption indication curve of the entire formation of the stratified steam injection well;

[0052] The tenth processing unit is used to determine the pressure P before the valve of each layer by referring to the limit value of the wellhead injection pressure f , and then according to the pressure P before each valve f Determine the valve hole size required for the injection valve to achieve precise injection.

[0053] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the above-mentioned calculation methods for stratified steam injection allocation in steam drive wells.

[0054] A fourth aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the calculation method for stratified steam injection allocation in steam-driven wells described in any one of the above items are implemented.

[0055] The present invention adopts the above technical solution, which has the following advantages:

[0056] 1. The deployment and calculation method of the present invention has a wide range of applications and can meet the deployment calculation requirements of most stratified steam injection processes.

[0057] 2. The present invention provides a method for calculating the valve core or valve hole area required for each layer of injection valve, and provides a method for accurately setting and distributing the valve hole area for the injection valve with a preset steam nozzle valve hole.

[0058] 3. The method of calculating the steam injection volume for each layer when the wellhead injection parameters change is explained. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic diagram of a layered steam injection column provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0061] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second", "third", "fourth" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0062] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outer side", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0063] Steam drive wells are affected by high temperature and high pressure, and the injection volume of each layer cannot be measured by tools, and the injection valve cannot be electrically controlled. Mechanical control methods are mainly used. In order to achieve formation injection, the valve hole of the injection valve needs to be adjusted. The lack of calculation method will result in no theoretical basis for valve hole adjustment. With the increase in the demand for steam drive allocation, it is necessary to adjust the reasonable valve hole formation calculation method according to the differences of each layer, so as to match the efficient allocation technology and improve the allocation efficiency of steam drive wells. At present, steam drive mining technology mainly focuses on insulation, parameter monitoring, layered steam injection process string, injection tools, layered injection volume calculation, etc., but there is no description of how to configure the valve hole for layered and segmented steam injection so that the steam injection of each section reaches the injection volume.

[0064] Based on the above technical problems, the present invention provides a steam-driven well stratified steam injection allocation design and diversion calculation method, device, medium and equipment. This method can be used to make up for the disadvantage that steam-driven wells cannot be accurately tested by testing instruments due to high temperature or well type, so as to allocate injection.

[0065] like Figure 1 As shown, taking three layers as an example, the calculation method for stratified steam injection allocation of steam drive wells provided by the present invention is divided into the following three situations:

[0066] One situation is: for a stratified steam injection well where the valve hole area of ​​each layer can be adjusted or the valve core can be replaced by wireline operation, a certain layer of injection valve injection channel is reserved in a top-down or bottom-up order by wireline fishing according to different process implementation methods, and other layer injection channels are blocked or closed. The wellhead injection pressure or injection displacement is adjusted by adjusting the wellhead valve, and the stable injection state data of at least three points are recorded to form a wellhead steam absorption indication curve or regression equation;

[0067] Furthermore, the formation steam absorption indication curve or regression equation is derived through ground test data, and the implementation process is as follows:

[0068] a) Select a point on the surface steam injection index curve (i.e., wellhead steam absorption index curve). The wellhead injection pressure, steam displacement and steam dryness of this point are known. According to the momentum conservation equation, the valve front pressure P at the current injection valve position can be obtained. f At this time, the mass loss does not need to be considered. It is recommended to use the Beggs-Brill method to calculate the pressure drop along the wellbore:

[0069]

[0070] Where: P1 is the starting point pressure, MPa; the depth increment is dz, and the pressure drop is dP f ρ m -Steam density, kg / m 3 ; G m - is the total mass flow rate of steam per unit cross-sectional area, kg / m 2 S; V m -Steam apparent velocity, m / s; V sg - gas phase apparent (converted) velocity, m / s; θ-the angle between the pipe section and the horizontal direction; λ-flow resistance; D-the inner diameter of the oil pipe, m; A-the cross-sectional area of ​​the oil pipe, m 2 .

[0071] b) Calculate the steam dryness from the wellhead to this point:

[0072]

[0073] Where: h l is the steam enthalpy, kJ / kg; h g -Gas phase enthalpy value, kJ / kg; x is the steam quality value; T is the temperature of each point in the wellbore; p is the pressure of each point in the wellbore; h is the steam enthalpy value, and z is the well temperature.

[0074] c) After obtaining the pressure and steam dryness at this point (steam is composed of water and gas, knowing the steam dryness and the corresponding saturation pressure, we can know the current density and the throttling loss ΔP m Related to steam density. ), combined with the ground steam mass flow, the valve hole throttling loss ΔP is calculated. m Calculation:

[0075]

[0076] Where: G Qm -Steam mass flow rate, kg / h; - Steam expansion coefficient; C d -Steam flow coefficient; A f - Valve hole cross-sectional area, m 2 ; ΔP m - injection valve throttling loss, Pa; β-the ratio of the valve hole shrinkage diameter d to the flow channel diameter before the valve.

[0077] d) Using the calculated pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , the formation suction pressure under the corresponding steam injection amount of the current layer can be obtained.

[0078] e) Repeat steps a)-d) and take 5 pressure points and corresponding injection volumes, and the formation steam absorption indication curve can be obtained. The injection volume of the reservoir should be combined and the injection volume data should be placed in the middle of the 5 pressure points.

[0079] f) Close the injection valve of the current layer, open the layer to be tested, and continue to test the other two layers according to steps a)-e) to obtain the formation steam absorption indication curve of each layer.

[0080] g) According to the measured formation steam absorption indication curve, find the wellhead injection pressure benchmark, the benchmark is mainly based on the highest wellhead injection pressure under the conditions of satisfying the injection volume of each layer, and the wellhead injection pressure of the whole well is increased by 1-2Mpa on this pressure. The wellhead injection pressure should not exceed the upper limit of the wellhead equipment pressure;

[0081] h) Under the current wellhead injection pressure, the valve pre-pressure of each layer is calculated along the wellbore according to the injection amount of the whole well and each layer. The throttling loss required by the injection valve of each layer can be obtained by subtracting the formation suction pressure under the injection amount of each layer from the valve pre-pressure. According to the valve hole throttling calculation formula (3), the valve hole size required for the injection valve can be obtained, thereby realizing fine injection.

[0082] The second situation: the injection valve is set with multiple gear valve holes. The gear adjustment, valve hole closing and opening are achieved by pressurizing the hydraulic control pipeline connecting the injection valve to the wellhead. Since the valve hole cannot be replaced later, it is necessary to reasonably design and calculate the valve hole area of ​​each gear before entering the well. Considering the overall layout and space limitations of the injection valve, taking the setting of four gear openings and full closing as an example, the design method is as follows:

[0083] The injection volume range of each layer is known, 1# layer, (q 1min ,q 1max ); 2# layer, (q 2min ,q 2max ); 3# layer, (q 3min ,q 3max ).

[0084] Arrange and combine the combinations with the largest difference in steam injection amount between layers. For example, set the injection amount of each layer to be q 1min、 q 2max、 q 3min or q 1max、 q 2min、 q 3max； ;

[0085] Furthermore, the pressure before the valve of each layer under the combination with the maximum difference in steam injection is calculated according to the wellhead injection capacity;

[0086] Further, the formation steam absorption pressure is calculated according to the formation steam absorption indication curve or formation test data of each layer;

[0087] Furthermore, by subtracting the formation steam absorption pressure from the pressure before the valve of each layer, the appropriate area of ​​the valve hole can be derived according to formula (3);

[0088] Furthermore, according to the maximum valve hole area and the minimum valve hole area of ​​each layer calculated by the difference combination of each steam injection amount, the valve hole areas of the other two gears are evenly arranged according to the four opening gears;

[0089] Furthermore, when production starts, the valve hole area under the corresponding injection amount can be calculated according to the mixing method of situation one, so as to adjust the injection valve to the appropriate gear position.

[0090] The third situation: When the wellhead injection parameters change, it is necessary to perform flow splitting calculations on each layer in the well to obtain the injection volume data for each layer. The calculation method is as follows:

[0091] It is known that the wellhead steam injection volume becomes Q c and the injection pressure becomes P c , calculate the injection volume Q according to formula (1) c Pressure drop ΔP flowing to 1# injection valve f , thus obtaining the valve front pressure P of 1# injection valve V1 ;

[0092] Furthermore, according to the area of ​​the valve hole currently configured for the 1# injection valve, the throttling loss ΔP of the current injection valve is calculated according to formula (3): m1 , use the valve front pressure P V1 Subtract ΔP m1 The formation steam absorption pressure P of the current layer can be obtained 01 ;

[0093] Further, according to the 1# layer formation steam absorption index curve or formation steam absorption test data, find the corresponding formation steam absorption pressure P 01 The displacement Q1 is the injection volume allocated to the 1# layer;

[0094] Furthermore, Q is calculated according to formula (1): c -Q1's displacement from 1# injection valve to 2# injection valve is measured by P V1 Subtract ΔP f1 , you can get the pressure P before the 2# injection valve 02 ;

[0095] Further, according to the 2# layer formation steam absorption index curve or formation steam absorption test data, find the corresponding formation steam absorption pressure P 01 The displacement Q2 is the injection volume allocated to the 2# layer;

[0096] Furthermore, the total displacement Q c Subtract the flow Q1 obtained on the 1# layer and the flow Q2 obtained on the 2# layer to obtain the flow obtained on the 3# layer.

[0097] At present, the stratified steam injection wells only focus on the design of the tubing process, but do not explain how to allocate each layer to the injection amount required by the reservoir for each process type. This invention provides a method for allocating steam for stratified steam injection in steam-driven wells, which is applicable to various stratified steam injection processes. The advantages of this invention are: 1. This invention has a wide range of applications and can meet the allocation calculation of most stratified steam injection processes; 2. This invention provides a method for calculating the valve core or valve hole area required for each layer of injection valve; 3. For the injection valve with a preset steam nozzle valve hole, a method for accurately setting and distributing the valve hole area is provided; 4. In response to changes in wellhead injection parameters, a method for calculating the steam injection amount of each layer is explained.

[0098] A second aspect of the present invention provides a computing device for steam injection allocation in steam drive wells, comprising:

[0099] The first processing unit is used to adjust the wellhead injection pressure or injection displacement by adjusting the wellhead valve for the stratified steam injection well where the fishing tool is lowered by wireline operation to adjust the valve hole area of ​​each layer or replace the valve core, record the stable injection state data of at least three points, and form a wellhead steam absorption indication curve;

[0100] The second processing unit is used to select a point on the wellhead steam suction indication curve with known wellhead injection pressure, steam displacement and steam dryness, and calculate the valve hole front pressure P at the current injection valve position. f ;

[0101] The third processing unit is used to calculate the steam quality of steam from the wellhead to the point;

[0102] The fourth processing unit is used to obtain the pressure P before the valve hole at this point f After calculating the steam quality, the throttling loss ΔP of the injection valve hole is calculated based on the ground steam mass flow rate. m ;

[0103] The fifth processing unit is used to utilize the pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , obtain the formation suction pressure under the corresponding steam injection amount of the current layer;

[0104] The sixth processing unit is used to repeat the steps of the first processing unit to the fifth processing unit, take a number of injection pressure points and corresponding injection displacements, and thus obtain a steam absorption indication curve of the formation;

[0105] The seventh processing unit is to reselect other strata of the stratified steam injection well, repeat the first processing unit to the sixth processing unit, and obtain the formation steam absorption indication curve of other strata;

[0106] An eighth processing unit is used to obtain a formation steam absorption indication curve of the entire formation of the stratified steam injection well according to the formation steam absorption indication curve of a certain formation obtained by the sixth processing unit and the formation steam absorption indication curves of other formations obtained by the seventh processing unit;

[0107] A ninth processing unit, determining a limit value of the wellhead injection pressure according to a formation steam absorption indication curve of the entire formation of the stratified steam injection well;

[0108] The tenth processing unit is used to determine the pressure P before the valve of each layer by referring to the limit value of the wellhead injection pressure f , and then according to the pressure P before each valve f Determine the valve hole size required for the injection valve to achieve precise injection.

[0109] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the above-mentioned calculation methods for stratified steam injection allocation in steam drive wells.

[0110] A fourth aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the calculation method for stratified steam injection allocation in steam-driven wells described in any one of the above items are implemented.

[0111] The present invention is described in terms of flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to specific embodiments. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0112] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calculation method for steam injection allocation in steam drive wells, characterized in that: include: S1: For stratified steam injection wells where fishing tools are lowered by wireline operation to adjust the valve hole area of ​​each layer or replace the valve core, the wellhead injection pressure or injection displacement is adjusted by adjusting the wellhead valve, and the stable injection state data of at least three points are recorded to form a wellhead steam absorption indication curve; S2: Select a point on the wellhead steam suction indication curve with known wellhead injection pressure, steam displacement and steam dryness, and calculate the pressure P before the valve hole at the current injection valve position. f ; S3: Calculate the steam dryness from the wellhead to this point; S4: Get the pressure P before the valve hole at this point f After calculating the steam quality, the throttling loss ΔP of the injection valve hole is calculated based on the ground steam mass flow rate. m ; S5: Using the pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , obtain the formation suction pressure under the corresponding steam injection amount of the current layer; S6: repeating steps S1-S5, taking a number of injection pressure points and corresponding injection displacements, and thus obtaining a steam absorption indication curve of the formation; S7: reselecting other strata of the stratified steam injection well, repeating steps S1 to S6, and obtaining formation steam absorption indication curves of other strata; S8: Obtaining a formation steam absorption indication curve for the entire formation of the stratified steam injection well according to the formation steam absorption indication curve of a certain formation obtained in step S6 and the formation steam absorption indication curves of other formations obtained in step S7; S9: Determine the limit value of the wellhead injection pressure according to the formation steam absorption indication curve of the whole formation of the stratified steam injection well; S10: Refer to the limit value of the wellhead injection pressure to determine the pressure P before the valve of each layer f , and then according to the pressure P before each valve f Determine the valve hole size required for the injection valve to achieve precise injection.

2. The calculation method for steam injection allocation in steam drive wells according to claim 1, characterized in that: When the injection valve is provided with multiple gear valve holes, the specific steps for adjusting the injection valve to the appropriate gear are as follows: A1: Knowing the range of steam injection volume for each layer, arrange and combine to find the combination with the largest difference in steam injection volume between layers; A2: Calculate the pressure P before the valve of each layer under the combination with the maximum steam injection difference according to the wellhead injection pressure f ; A3: Calculate the formation steam absorption pressure based on the formation steam absorption indication curve or formation test data of each layer; A4: Use the pressure P before each valve f Subtract the formation steam absorption pressure to calculate the appropriate area of ​​the valve hole; A5: Based on the maximum and minimum valve hole areas of each layer calculated according to the difference in steam injection volume, evenly arrange the valve hole areas of other gears according to the appropriate opening gear; A6: When starting production, calculate the valve hole area under the corresponding injection amount according to the mixing method of claim 1, so as to adjust the injection valve to the appropriate gear position.

3. The calculation method for steam injection allocation in steam drive wells according to claim 1, characterized in that: When the wellhead injection parameters change, it is necessary to perform flow splitting calculations on each layer in the well to obtain the injection volume data for each layer. The specific method is as follows: B1: The known wellhead steam injection volume becomes Q c and the injection pressure becomes P c , according to the pressure before the valve P f The total displacement Q is calculated by the calculation formula c Pressure drop ΔP flowing to a certain injection valve f , thus obtaining the valve front pressure P of the injection valve V1 ; B2: According to the area of ​​the currently configured valve hole of the injection valve in B1, the throttling loss ΔP of the injection valve hole m The calculation formula is used to calculate the throttling loss ΔP of the current injection valve. m1 , use the valve front pressure P V1 Subtract ΔP m1 The formation steam absorption pressure P of the current layer can be obtained 01 ; B3: According to the formation steam absorption index curve or formation steam absorption test data of the injection valve in B1, find the corresponding formation steam absorption pressure P 01 The displacement Q1 is the injection volume allocated to the injection valve layer in B1; B4: According to the pressure before the valve P f The calculation formula for calculating Q c -Q1 displacement from the injection valve in B1 to the other injection valve pressure drop, denoted by P V1 Subtract ΔP f1 , you can get the pressure P before the other injection valve 02 ; B5: According to the formation steam absorption index curve or formation steam absorption test data of another injection valve, find the corresponding formation steam absorption pressure P 01 The displacement Q2 is the injection volume allocated to another injection valve layer; B6: Use total displacement Q c Subtract the displacement Q1 allocated to the injection valve layer in B1 and the displacement Q2 allocated to another injection valve layer to obtain the displacement allocated to the third layer.

4. The calculation method for steam injection allocation in steam drive wells according to claim 1, characterized in that: The pressure P before the valve hole in step S2 f The calculation formula is as follows: Where P1 is the starting point pressure; the depth increment is dz, and the pressure drop is dP f ρ m is the steam density; G m is the total mass flow rate of steam per unit cross-sectional area; V m V is the superficial velocity of steam; sg is the gas phase apparent (converted) velocity; θ is the angle between the pipe section and the horizontal direction; λ is the flow resistance; D is the inner diameter of the oil pipe; A is the cross-sectional area of ​​the oil pipe.

5. The calculation method for steam injection allocation in steam drive wells according to claim 1, characterized in that: In step S3, the steam quality of steam from the wellhead to the point is calculated, and the specific formula is as follows: In the formula, h l is the steam enthalpy; h g is the gas phase enthalpy value; x is the steam quality value; T is the temperature of each point in the wellbore; p is the pressure of each point in the wellbore; h is the steam enthalpy value, and z is the well temperature.

6. The calculation method for steam injection allocation in steam drive wells according to claim 1, characterized in that: The throttling loss ΔP of the injection valve hole in step S4 m The calculation formula is as follows: In the formula, G Qm is the steam mass flow rate; is the steam expansion coefficient; C d is the steam flow coefficient; A f is the cross-sectional area of ​​the valve hole; ΔP m is the throttling loss of the injection valve; β is the ratio of the valve hole diameter d to the diameter of the flow channel before the valve.

7. A calculation device for steam injection allocation in steam drive wells, characterized in that: include: The first processing unit is used to adjust the wellhead injection pressure or injection displacement by adjusting the wellhead valve for the stratified steam injection well where the fishing tool is lowered by wireline operation to adjust the valve hole area of ​​each layer or replace the valve core, record the stable injection state data of at least three points, and form a wellhead steam absorption indication curve; The second processing unit is used to select a point on the wellhead steam suction indication curve with known wellhead injection pressure, steam displacement and steam dryness, and calculate the valve hole front pressure P at the current injection valve position. f ; The third processing unit is used to calculate the steam quality of steam from the wellhead to the point; The fourth processing unit is used to obtain the pressure P before the valve hole at this point f After calculating the steam quality, the throttling loss ΔP of the injection valve hole is calculated based on the ground steam mass flow rate. m ; The fifth processing unit is used to utilize the pressure P before the valve hole f Subtract the throttling loss of the injection valve hole ΔP m , obtain the formation suction pressure under the corresponding steam injection amount of the current layer; The sixth processing unit is used to repeat the steps of the first processing unit to the fifth processing unit, take a number of injection pressure points and corresponding injection displacements, and thus obtain a steam absorption indication curve of the formation; The seventh processing unit is to reselect other strata of the stratified steam injection well, repeat the first processing unit to the sixth processing unit, and obtain the formation steam absorption indication curve of other strata; An eighth processing unit is used to obtain a formation steam absorption indication curve of the entire formation of the stratified steam injection well according to the formation steam absorption indication curve of a certain formation obtained by the sixth processing unit and the formation steam absorption indication curves of other formations obtained by the seventh processing unit; A ninth processing unit, determining a limit value of the wellhead injection pressure according to a formation steam absorption indication curve of the entire formation of the stratified steam injection well; The tenth processing unit is used to determine the pressure P before the valve of each layer by referring to the limit value of the wellhead injection pressure f , and then according to the pressure P before each valve f Determine the valve hole size required for the injection valve to achieve precise injection.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the calculation method for stratified steam injection allocation in steam drive wells according to any one of claims 1 to 6 are implemented.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the calculation method for stratified steam injection allocation in steam drive wells according to any one of claims 1 to 6 are implemented.

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