Method for acquiring chemical flooding injection-production communication type

Abstract

The invention relates to the technical field of oil reservoir engineering and tertiary oil recovery, in particular to a method for obtaining a chemical flooding injection-production communication type. The method comprises the following steps: determining a chemical flooding target block, and obtaining basic static data of the chemical flooding target block; checking and verifying element data in the basic static data, and establishing target block associated information; the effective thickness and the deposition phase of each deposition unit are determined, and whether chemical flooding is effectively connected or not is determined; injection-production communication types are judged, calculated and classified through the injection-production communication type thickness judgment coefficient; the total effective thickness and the thickness proportion of the injection-production communication type are obtained; the injection-production communication type of the injection-production well group of the chemical flooding multilayer heterogeneous reservoir is obtained; and according to the injection-production communication type, scheme design before polymer injection or injection parameter adjustment in the polymer flooding process is conducted, and the fracturing measure transformation opportunity is determined. According to the method for obtaining the chemical flooding injection-production communication type, calculation is accurate, evaluation is objective and real, and the bottleneck in the prior art is broken through.

Description

Technical Field

[0001] The invention relates to the technical field of oil reservoir engineering and tertiary oil recovery, and in particular to a method for obtaining a chemical drive injection-production connection type. Background Art

[0002] With the continuous expansion of the scale of chemical flooding in oil fields, the conditions of the oil layers under development have gradually deteriorated. The number of imperfect injection-production connectivity types, such as thin injection and thick production, thick injection and thin production, has increased, directly affecting the effect of polymer flooding development. It is necessary to design personalized solutions and measures for different types of oil layers. Therefore, the discrimination and calculation of different injection-production connectivity types in chemical flooding oil layers is crucial. At present, there is no relevant research on the calculation method of injection-production connectivity type in chemical flooding oil layers at home and abroad. In the past, the identification of injection-production connectivity types, such as thin injection and thick production, thick injection and thin production, was mainly based on researchers' manual map recognition or subjective and fuzzy judgment based on the thickness of oil and water wells, resulting in inaccurate division methods. At the same time, there are many wells and sedimentary units in the actual blocks of the mine, and the workload of obtaining the injection-production connectivity types of oil layers and well groups is large. The acquisition process is time-consuming and labor-intensive, and it is difficult to achieve convenient and quick acquisition. Therefore, in view of the above shortcomings, a method for obtaining the injection-production connectivity type of chemical flooding is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The present invention provides a method for obtaining the injection-production connectivity type of chemical drive, thereby avoiding the problem in the prior art where there is no definite calculation method, resulting in researchers only being able to judge the injection-production connectivity type of the chemical drive layer by manual map recognition or subjective and fuzzy judgment based on the thickness of oil and water wells, which leads to improper classification of the injection-production connectivity type and large errors.

[0005] (II) Technical solution

[0006] In order to solve the above problems, the present invention provides a method for obtaining the chemical flooding injection-production connection type, comprising:

[0007] Step S1: determine the chemical flooding target block, divide the deposition unit, and obtain basic static data of the chemical flooding target block;

[0008] Step S2: determining the target well, central well and connected well for chemical flooding, performing data proofreading on the element data involved in the determination of the connection type in the basic static data of step S1, verifying the validity of the data, and establishing the target block association information;

[0009] Step S3: determining the effective thickness and sedimentary phase of the target well and the connected wells for chemical flooding in each sedimentary unit, and determining that the central well and the surrounding connected wells are effectively connected for chemical flooding in each sedimentary unit;

[0010] Step S4: Use the injection-production connection type thickness discrimination coefficient to calculate the injection-production connection type determination for each connection direction of the sedimentary unit, and classify according to the injection-production connection type;

[0011] Step S5: Obtain the total effective thickness and thickness ratio of the injection-production connection type for each target sedimentary unit and target block of the chemical flooding target well;

[0012] Step S6: Obtain the injection-production connection type of the chemical flooding injection-production well group;

[0013] Step S7: According to the injection-production connection type of each sedimentary unit of the chemical flooding target well and the injection-production connection type of the well group, carry out the pre-polymer injection plan design or adjust the injection parameters during the polymer flooding process, and determine the transformation timing of the fracturing measures.

[0014] Preferably, in the step S1, the basic static data of the chemical flooding target block includes the injection-production well numbers of the target block, the reservoir data of the sedimentary units of the oil and water wells, the sedimentary facies data of the oil and water wells, the connection library of the oil and water wells, and the perforation data.

[0015] Preferably, in the step S3, the method for judging the sedimentary facies is that when a single well develops channel sand or inter-channel sand, it is a connected facies, and when a single well develops pinch-out or off-specification, it is considered a non-connected facies.

[0016] Preferably, in the step S3, the method for judging the effective connection of chemical flooding is that when any one of the central well and the connected wells is off-specification or pinch-out, it is judged as a non-connected type, including verifying the facies of the intermediate transition wells. When the facies of the intermediate wells is off-specification or pinch-out facies, it is considered that the injection-production is not connected.

[0017] Preferably, in the step S4, the injection-production connection types include thick injection and thick production type, thin injection and thick production type, thick injection and thin production type, thin injection and thin production type, and non-connected type.

[0018] Preferably, for the thick injection and thick production type: the effective thickness ratio of the injection-production wells is 0.3 < A < 3; for the thick injection and thin production type: the effective thickness ratio of the injection-production wells is A ≥ 3; for the thin injection and thick production type: the effective thickness ratio of the injection-production wells is A ≤ 0.3; for the thin injection and thin production type: the effective thickness of both the oil and water wells is h ≤ 0.5 m; for the non-connected type: when any one of the oil and water wells is pinch-out or off-specification, or the sedimentary facies of the intermediate transition well is pinch-out or off-specification, it is judged as a non-connected type.

[0019] Preferably, in the step S6, the chemical flooding injection-production well group is four oil wells connected with a water well as the center or four water wells connected with an oil well as the center.

[0020] Preferably, in the step S5, the situation of obtaining the effective thickness and thickness ratio of each injection-production connection type of the target well, target sedimentary unit and target block:

[0021] (1) Calculate the ratio of the connection thickness of each injection-production connection type of the target well x on the sedimentary unit i:

[0022]

[0023] Among them, E xi-注采连通类型 is the thickness ratio of each injection-production connection type of target well x on sedimentary unit i, h xi-注采连通类型 is the effective thickness of each injection-production connection type of target well x on sedimentary unit i, h xi is the effective thickness of target well x on deposition unit i, h xi-连通井 is the effective thickness of the oil well connected to the central well, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; n is the number of connections of different injection-production connection types of well x on sedimentary unit i, n≤4; m is the number of connection directions of well x on sedimentary unit i, m≤4;

[0024] (2) Calculate the proportion of the connected thickness of each injection-production connection type for all wells in the target block on the i-th sedimentary unit:

[0025]

[0026] Among them, E i-注采连通类型 is the thickness ratio of each injection-production connection type of all wells in the i-th sedimentary unit, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in sedimentary unit i;

[0027] (3) Calculate the total connected thickness ratio of each injection-production connection type for all wells in the target block in all sedimentary units (blocks):

[0028]

[0029] Among them, E 区块注采连通类型 is the total connected thickness ratio of each injection-production connection type of all wells in the target block on all sedimentary units (blocks), and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in the target block, and q is the total number of sedimentary units in the target block.

[0030] Preferably, in step S6, the thickness of the single layer, the number of connected directions and the ratio of the thickness of the thin and thick layers are considered, and the connectivity coefficient E is applied. 井组 The well group connectivity type is determined, and the calculation formula is:

[0031]

[0032]

[0033]

[0034] Among them, h 单层碾平i is the thickness of single layer development, η 厚度比例i is the thickness ratio, E 井组连通系数 is the well group connectivity coefficient, h 连通井i is the effective thickness of the center well, k i is the number of connected directions of the central well on sedimentary unit i; h 连通井i is the effective thickness of the oil well connected to the central well, m; m is the number of sedimentary units.

[0035] Preferably, the judgment principle of the well group connectivity type is: when E 井组连通系数 When E ≤0.3, the well group belongs to the thin injection and thick production type; 井组连通系数 ≥3, the well group belongs to the thick injection and thin production type; when 0.3 <E 井组连通系数 <3, and the thickness of oil and water wells is relatively large, the well group belongs to the thick injection and thick production type; when 0.3 <E 井组连通系数 <3, and the development of oil and water wells is poor, the well group belongs to the thin injection and thin production type.

[0036] (III) Beneficial effects

[0037] The method for obtaining the injection-production connection type of chemical drive provided by the present invention has accurate and fast calculation, objective and true evaluation, and effectively solves the unreasonable personalized scheme design of oil layer injection parameters of different injection-production connection types before chemical drive, avoids the imperfection of injection-production connection types in the development and adjustment process of chemical drive, successfully improves the large limitations of the transformation parameters of oil layer fracturing measures, and breaks through the technical bottleneck of only being able to make fuzzy subjective judgments with large errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic flow chart of a method for obtaining a chemical flooding injection-production connection type according to an embodiment of the present invention;

[0039] Figure 2 This is a diagram showing the influence of the ratio of the thickness of the thin / thick layers on the improvement of the polymer flooding recovery factor in a thick injection and thin production well group according to an embodiment of the present invention;

[0040] Figure 3 This is a diagram showing the influence of the ratio of the thickness of thin / thick layers on the improvement of polymer flooding recovery in a thin-injection-thick-production well group according to an embodiment of the present invention;

[0041] Figure 4 This is a diagram showing the effect of injection velocity on polymer flooding effect of oil layers with different injection-production connection types according to an embodiment of the present invention;

[0042] Figure 5 This is a diagram showing the influence of injection concentration on polymer flooding effect of oil layers with different injection-production connection types according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 technicians in this field without creative work are within the scope of protection of the present invention.

[0044] like Figure 1 As shown, the present invention provides a method for obtaining the chemical flooding injection-production connection type. The working principle of the method for obtaining the chemical flooding injection-production connection type is described in detail below:

[0045] Step S1: determine the chemical flooding target block, divide the deposition unit, and obtain basic static data of the chemical flooding target block.

[0046] In practical applications, the basic static data of the target block of chemical flooding includes the injection and production well number of the target block, the reservoir data of the oil and water well sedimentary unit, the sedimentary phase data of the oil and water well, the oil and water well connection library and the perforation data. It should be noted that the basic data of the target block can be but not limited to the above data, as long as it is conducive to obtaining the layer and well injection and production connection type. In this embodiment, a typical Class II oil layer block in the northern area of ​​a domestic oil field is taken as the research object. The block is a five-point area well network with a well spacing of 150 meters. There are 237 injection and production wells, including 107 injection wells and 130 oil production wells. In practical applications, the target layer for exploitation is Grape II 7 to High I4+5, and 8 sedimentary units are developed. The basic data of the block include: the injection and production well number of the block, the injection and production well connection well number library, the reservoir data of the sedimentary unit, the sedimentary phase data, the small layer database and the perforation library.

[0047] Step S2: Determine the target well, central well and connected well for chemical flooding, perform data proofreading on the element data related to the connection type determination in the basic static data of step S1, verify the validity of the data, and establish the target block association information.

[0048] In this method, the sedimentary unit reservoir data, sedimentary phase data and perforation data are associated data for connection type determination. Extracting element data requires not only data correction but also verification of data validity. In this embodiment, the target well is a water well and the connected well is an oil well. The injection-production connection type of the block with the water well as the center is counted, including the target well number, the well number connected to the target well, the sedimentary unit name, the sedimentary phase category of each well in each sedimentary unit, the effective thickness of each well in each sedimentary unit and other elements. It is necessary to check whether the sedimentary phase data and the effective thickness of a single well in the perforation data are consistent in each sedimentary unit to verify the validity of the data.

[0049] Step S3: Determine the effective thickness and sedimentary phase of the target wells and connected wells for chemical flooding in each sedimentary unit, and determine whether the central well and the surrounding connected wells are effectively connected for chemical flooding in each sedimentary unit.

[0050] In the present method, the sedimentary phase difference is determined as connected phase difference when a single well develops channel sand and inter-channel sand, and is determined as disconnected phase difference when a single well develops pinch-out or out-of-surface. In practical applications, the method for determining effective connectivity of chemical drive is to determine it as disconnected type when any one of the central well and the connected well is out-of-surface or pinch-out, including checking the phase difference of the intermediate transition well. When the phase difference of the intermediate well is out-of-surface or pinch-out phase difference, it is determined as injection-production disconnection. In this embodiment, it is determined that the target well x and the connected well are effectively connected by chemical drive in each sedimentary unit, and the phase difference of the intermediate well of the chemical drive injection-production well is verified. According to the sedimentary phase belt map of each sedimentary unit in the target block, if the phase difference of the intermediate well is pinch-out or out-of-surface, due to the existence of the intermediate non-connected phase, it is considered that the direction is disconnected, and the intermediate well phase difference column is marked as pinch-out or out-of-surface.

[0051] In this embodiment, as shown in Tables 1-1 to 1-4, the associated data table is calculated based on the injection-production connectivity type of each sedimentary unit established in step S2. The associated data table includes the following information: target well number, target well connectivity direction number, target well sedimentary phase, target well effective thickness, connected well number 1, whether the intermediate well phase is pinched out or out of the table. If the intermediate well phase is pinched out or out of the table, the direction is considered to be a disconnected type, and the disconnected thickness of the well is h. xi +h 连通井1 , thick injection and thick production connected thickness, thick injection and thin production connected thickness, thin injection and thick production connected thickness, thin injection and thin production connected thickness, disconnected thickness, target well-connected well 1 injection and production connection type, and so on connected well 4..., total connected thickness of target well xi, total connected thickness of thick injection and thick production, total connected thickness of thick injection and thin production, total connected thickness of thin injection and thick production, total connected thickness of thin injection and thin production, and total disconnected thickness.

[0052] Table 1-1 Basic data table of injection-production connectivity status of sedimentary unit P27 in target block (main well and connected well 1)

[0053]

[0054]

[0055] Table 1-2 Basic data table of injection-production connectivity status of sedimentary unit P27 in target block (connected well 2)

[0056]

[0057]

[0058] Table 1-3 Basic Table of Associated Data on Injection-Production Connection Status of Sedimentary Units in Target Block P27 (Connected Wells 3)

[0059]

[0060] Table 1-4 Basic Table of Associated Data on Injection-Production Connection Status of Sedimentary Units in Target Block P27 (Connected Wells 4)

[0061]

[0062] Step S4: Use the thickness discrimination coefficient of injection-production connection types to calculate the determination of injection-production connection types in each connected direction of the sedimentary unit, and classify according to the injection-production connection types.

[0063] In this embodiment, based on the sedimentary facies type and effective thickness of the target single well x and the surrounding connected wells determined in step S3 on sedimentary unit i, judge the corresponding injection-production connection types of the single well x and the surrounding connected wells, namely thick injection-thick production, thick injection-thin production, thin injection-thick production, thin injection-thin production, and non-connected types. It should be noted that in the past, the dividing line thickness between thin injection-thick production and thick injection-thin production was not clear. Applying the research results of reservoir numerical simulation, the ratio of the thickness of thin layers to thick layers of injection-production wells will only have an obvious impact on the polymer flooding recovery factor when it is ≤ 0.3. As Figure 2 and Figure 3 shown, the basis for the determination standard of single-layer injection-production connection types in this method is exactly the use of the research results of reservoir numerical studies.

[0064] In practical applications, the principle for dividing single-layer injection-production connection types is as follows: Thick injection-thick production type: The ratio of the effective thickness of injection-production wells is 0.3 < A < 3; Thick injection-thin production type: The ratio of the effective thickness of injection-production wells is A ≥ 3; Thin injection-thick production type: The ratio of the effective thickness of injection-production wells is A ≤ 0.3; Thin injection-thin production type: The effective thickness of both oil and water wells is h ≤ 0.5 m; Non-connected type: If any one of the oil and water wells is pinched out or outside the table, or the sedimentary facies of the intermediate transition well is pinched out or outside the table, it is determined as the non-connected type.

[0065] In this embodiment, the method for determining injection-production connection types is implemented in the form of writing statements in excel. The thicknesses of injection-production connection types are respectively the effective thickness of the target single well x on sedimentary unit i plus the effective thickness of the connected wells on sedimentary unit i. Tables 2-1 to 2-5 are for identifying the injection-production types in each connected direction of a single layer, and the results are shown in Tables 2-1 to 2-5.

[0066] Table 2-1 Associated Data Table on Injection-Production Connection Type Status of Sedimentary Units in Target Block P27 (Main Well and Connected Well 1)

[0067]

[0068]

[0069] Table 2-2 Target Block P27 Sedimentary Unit Injection-Production Connectivity Type Status Correlation Data Table (Connected Well 2)

[0070]

[0071]

[0072] Table 2-3 Target Block P27 Sedimentary Unit Injection-Production Connectivity Type Status Correlation Data Table (Connected Well 3)

[0073]

[0074]

[0075] Table 2-4 Target Block P27 Sedimentary Unit Injection-Production Connectivity Type Status Correlation Data Table (Connected Well 4)

[0076]

[0077]

[0078] Table 2-5 Data table of injection-production connection type status of sedimentary unit in target block P27 (overall connection thickness statistics)

[0079]

[0080]

[0081] Step S5: Obtain the total effective thickness and thickness ratio of each target sedimentary unit and injection-production connectivity type of the target block in the chemical flooding target well.

[0082] In this method, the thickness and type of the injection-production connection type between the target well and the connected well in each sedimentary unit are obtained according to the above steps, and the effective thickness ratio of each injection-production connection type in each sedimentary unit and target block of the chemical flooding target well is obtained:

[0083] (1) Calculate the ratio of the connection thickness of each injection-production connection type of the target well x on the sedimentary unit i:

[0084]

[0085] Among them, E xi-注采连通类型 is the thickness ratio of each injection-production connection type of target well x on sedimentary unit i, h xi-注采连通类型 is the effective thickness of each injection-production connection type of target well x on sedimentary unit i, h xi is the effective thickness of target well x on deposition unit i, h xi-连通井is the effective thickness of the oil well connected to the central well, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; n is the number of connections of well x in different injection-production connection types on sedimentary unit i, n≤4; m is the number of connection directions of well x on sedimentary unit i, m≤4.

[0086] In practical applications, taking the L7-AS1126 well as an example, the number of connected directions of the water well in the P27 unit is 4, and the effective thickness is 4m. The effective thickness of the connected oil well 1 is 2.8m, and the effective thickness ratio A of the injection and production wells is equal to 1.43, which is a thick injection and thick production type. The connected thickness of thick injection and thick production is the sum of the effective thicknesses of the injection and production wells, which is 6.8m; the effective thickness of the connected oil well 2 is 1m, and the effective thickness ratio A of the injection and production wells is equal to 4, which belongs to the thick injection and thin production type, and the connected thickness of thick injection and thin production is the sum of the effective thicknesses of the injection and production wells, which is 5m; the effective thickness of the connected oil well 3 is 0.2m, and the effective thickness ratio A of the injection and production wells is equal to 20, which belongs to the thick injection and thin production type, and the connected thickness of thick injection and thin production is the sum of the effective thicknesses of the injection and production wells, which is 4.2m; the effective thickness of the connected oil well 4 is 2.8m, and the connected thickness ratio A of the injection and production wells is equal to 1, which belongs to the thick injection and thick production type, and the connected thickness of thick injection and thick production is the sum of the effective thicknesses of the injection and production wells, which is 6.8m. Therefore, the injection-production connection types of L7-AS1126 in the four connection directions on the P27 unit are thick injection and thick production, thick injection and thin production, thick injection and thin production, and thick injection and thick production. The connection thickness ratio of each injection-production type is:

[0087]

[0088]

[0089] Therefore, the injection-production connection types and thickness ratios of other wells in each connection direction on the P27 sedimentary unit can be obtained in the same way. Similarly, the injection-production connection type thickness and ratio of all wells in P28+9, P2101, P2102, G11, G12, G13 and G14+5 units can be obtained.

[0090] (2) Calculate the proportion of the connected thickness of each injection-production connection type for all wells in the target block on the i-th sedimentary unit:

[0091]

[0092] Among them, E i-注采连通类型 is the thickness ratio of each injection-production connection type of all wells in the i-th sedimentary unit, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in sedimentary unit i.

[0093] In practical applications, the overall connection thickness of the target well in each sedimentary unit and the effective thickness of different injection-production connection types are obtained according to (1), and the thickness ratio of the injection-production connection type of the target well in each sedimentary unit can be obtained. Taking the P27 unit as an example:

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] (3) Calculate the total connected thickness ratio of each injection-production connection type for all wells in the target block in all sedimentary units (blocks):

[0100]

[0101] Among them, E 区块注采连通类型 is the total connected thickness ratio of each injection-production connection type of all wells in the target block on all sedimentary units (blocks), and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in the target block, and q is the total number of sedimentary units in the target block.

[0102] As shown in Tables 3-1 and 3-2, it can be obtained that the overall injection-production connection type connection thickness ratio of the example block is 61.99% for thick injection and thick production, 9.64% for thick injection and thin production, 8.56% for thin injection and thick production, 8.56% for thin injection and thin production, and 18.92% for disconnected thickness.

[0103] Table 3-1 Target block injection-production connectivity type results

[0104]

[0105]

[0106] Table 3-2 Target block injection-production connectivity type results

[0107]

[0108]

[0109] Step S6: Obtain the injection-production connectivity type of the chemical flooding injection-production well group.

[0110] In this method, considering the single-layer development thickness, the number of connected directions, and the thickness ratio of thin and thick layers, the connectivity coefficient E is applied. 井组 To determine the connectivity type of the well group, the calculation formula is:

[0111]

[0112]

[0113]

[0114] Where h 单层碾平i is the single-layer development thickness, η 厚度比例i is the thickness ratio, E 井组连通系数 is the well group connectivity coefficient, h 连通井i is the effective thickness of the central well, k i is the number of connected directions of the central well in sedimentary unit i; h 连通井i is the effective thickness of the oil wells connected to the central well, m; m is the number of sedimentary units.

[0115] The chemical flooding injection-production well group is to connect four oil wells with a water well as the center or connect four water wells with an oil well as the center. The judgment principle for the connectivity type of the well group is: when the well group connectivity coefficient E ≤ 0.3, the well group belongs to the thin injection and thick production type; when the well group connectivity coefficient E ≥ 3, the well group belongs to the thick injection and thin production type; when 0.3 < E well group connectivity coefficient < 3 and the development thicknesses of both oil and water wells are relatively large, the well group belongs to the thick injection and thick production type; when 0.3 < E well group connectivity coefficient < 3 and the developments of both oil and water wells are relatively poor, the well group belongs to the thin injection and thin production type. In this embodiment, taking the injection-production complete well group as an example, with a water well as the center and four oil wells connected around it, considering the single-layer flattened thickness, the number of connected directions, and the thickness ratio, the connectivity coefficient E of the well group is used to determine the connectivity type of the well group. As shown in Table 4, the single-layer flattened thickness and the thickness ratio are calculated based on the effective thickness and the number of connected directions of the injection-production wells. According to the formula, the well group connectivity coefficient is calculated to be 0.9, and the development thicknesses of both oil and water wells are relatively high, so the well group belongs to the thick injection and thick production type.

[0116] Table 4 is the basic database for determining the injection-production connectivity type of the L7-PS1526 well group

[0117]

[0118] Step S7: According to the injection-production connectivity types of each sedimentary unit of the chemical flooding target well and the injection-production connectivity type of the well group, carry out the pre-polymer injection plan design or adjust the injection parameters during the polymer flooding process to determine the fracturing measure transformation timing.

[0119] In this embodiment, according to steps S1-S6, the target chemical flooding block and the injection-production connection type of the well group are determined. The polymer flooding development of Daqing Oilfield has entered the stage of precise regulation and deep potential tapping, and it is necessary to design the injection parameters and the timing of the adjustment measures in a personalized way. According to the results of the numerical simulation study, Figure 4 and Figure 5 As shown, both thin-injection-thick-production and thick-injection-thin-production layers are not suitable for high injection rates. Thin-injection-thick-production layers are suitable for low-injection-concentration and medium-speed production, while thick-injection-thin-production layers are suitable for high-concentration and low-injection-rate production. Thin-injection-thick-production layers and thick-injection-thin-production layers require fracturing during polymer flooding development. Water wells in thin-injection-thick-production layers have the best fracturing effect at the initial stage of polymer injection, while oil wells in thick-injection-thin-production layers should not be fractured too early. Fracturing in the low water content period or recovery period can achieve a higher recovery rate.

[0120] In practical applications, the present invention is compared with the existing manual judgment acquisition method based only on the development thickness or the connection fence diagram: the disadvantage of the conventional method for judging the injection-production connection type is that the thickness boundary is not clear, especially the fuzzy thickness division of thin injection and thick production, thick injection and thin production, and strong subjectivity. The judgment results of different people are often quite different. At the same time, the difference between the intermediate transition wells is not fully considered, which makes the calculated injection-production connection type inaccurate. The thickness ratio method is used for the chemical flooding injection-production connection type of the single layer and well group of the target block. It is based on the previous theoretical research results of reservoir numerical simulation. The judgment principle is more rigorous and accurate, and the database established by using Excel can achieve rapid identification, and then compared with the results of the conventional method. The acquisition method provided by this patent is more accurate and reliable, and the work intensity is reduced.

[0121] The method for obtaining the injection-production connectivity type of chemical drive provided by the present invention can realize the accurate and rapid calculation of the connectivity type of injection-production well groups from a single-layer single connectivity direction to a multi-layer multi-connectivity direction in a chemical drive oil reservoir. The method can be used to objectively evaluate the injection-production connectivity quality of the reservoir in the chemical drive block, effectively solve the unreasonable personalized scheme design of oil layer injection parameters of different injection-production connectivity types before chemical drive, avoid the imperfection of the injection-production connectivity type in the development and adjustment process of chemical drive, successfully improve the large limitations of the transformation parameters of the oil layer fracturing measures, and break through the technical bottleneck of only being able to make fuzzy subjective judgments with large errors.

[0122] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for obtaining the connection type of chemical flooding injection and production, characterized in that: Including: Step S1: Determine the target block for chemical flooding, divide the sedimentary units, and obtain the basic static data of the target block for chemical flooding; Step S2: Determine the target wells, central well, and connected wells for chemical flooding, proofread the element data related to the determination of the connection type in the basic static data of Step S1, verify the validity of the data, and establish the associated information of the target block; Step S3: Determine the effective thickness and sedimentary facies of the target wells and connected wells for chemical flooding in each sedimentary unit, and determine the effective chemical flooding connection between the central well and the surrounding connected wells in each sedimentary unit; Step S4: Use the thickness discrimination coefficient for injection-production connection types to calculate and determine the injection-production connection type in each connection direction of the sedimentary unit, and classify according to the injection-production connection type; Step S5: Obtain the total effective thickness and thickness ratio of the injection-production connection types of each target sedimentary unit and target block of the target wells for chemical flooding; Step S6: Obtain the injection-production connection type of the chemical flooding injection-production well group; Step S7: According to the injection-production connection type of each sedimentary unit of the target wells for chemical flooding and the injection-production connection type of the well group, carry out the pre-polymer injection plan design or adjust the injection parameters during the polymer flooding process, and determine the timing of fracturing measure transformation.

2. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S1, the basic static data of the target block for chemical flooding includes the injection-production well numbers of the target block, the reservoir data of the oil and water wells in the sedimentary unit, the sedimentary facies data of the oil and water wells, the connection library of the oil and water wells, and the perforation data.

3. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S3, the method for judging the sedimentary facies is that when a single well develops channel sand or inter-channel sand, it is the connected facies, and when a single well develops pinch-out or outside the table, it is considered the unconnected facies.

4. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S3, the method for judging the effective chemical flooding connection is that when any one of the central well and the connected wells is outside the table or pinch-out, it is judged as the unconnected type, including verifying the sedimentary facies of the intermediate transition wells. When the sedimentary facies of the intermediate wells is outside the table or pinch-out facies, it is considered that the injection-production is not connected.

5. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S4, the injection-production connection types include thick injection-thick production type, thin injection-thick production type, thick injection-thin production type, thin injection-thin production type, and unconnected type.

6. The method for obtaining the chemical flooding injection-production connection type according to claim 5, characterized in that: For the thick injection-thick production type: the effective thickness ratio of the injection-production wells is 0.3 < A < 3; for the thick injection-thin production type: the effective thickness ratio of the injection-production wells is A ≥ 3; for the thin injection-thick production type: the effective thickness ratio of the injection-production wells is A ≤ 0.3; for the thin injection-thin production type: the effective thickness of both the oil and water wells is h ≤ 0.5 m; for the unconnected type: when any one of the oil and water wells is pinch-out or outside the table, or the sedimentary facies of the intermediate transition well is pinch-out or outside the table, it is judged as the unconnected type.

7. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S6, the chemical flooding injection-production well group is centered on a water well and connected to four oil wells, or centered on an oil well and connected to four water wells.

8. The method for obtaining the chemical flooding injection-production connection type according to claim 1, characterized in that: In Step S5, the situation of obtaining the effective thickness and thickness ratio of each injection-production connection type of the target well, target sedimentary unit, and target block: (1) Calculate the connection thickness ratio of each injection-production connection type of target well x in sedimentary unit i: Among them, E xi-注采连通类型 is the thickness ratio of each injection-production connection type of target well x on sedimentary unit i, h xi-注采连通类型 is the effective thickness of each injection-production connection type of target well x on sedimentary unit i, h xi is the effective thickness of target well x on deposition unit i, h xi-连通井 is the effective thickness of the oil well connected to the central well, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; n is the number of connections of different injection-production connection types of well x on sedimentary unit i, n≤4; m is the number of connection directions of well x on sedimentary unit i, m≤4; (2) Calculate the connection thickness ratio of each injection-production connection type of all wells in the target block in the i-th sedimentary unit: Among them, E i-注采连通类型 is the thickness ratio of each injection-production connection type of all wells in the i-th sedimentary unit, and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in sedimentary unit i; (3) Calculate the total connection thickness ratio of each injection-production connection type of all wells in all sedimentary units (block) of the target block: Among them, E 区块注采连通类型 is the total connected thickness ratio of each injection-production connection type of all wells in the target block on all sedimentary units (blocks), and the injection-production connection types are thick injection and thick production, thick injection and thin production, thin injection and thick production, thin injection and thin production, and no connection; p is the total number of wells in the target block, and q is the total number of sedimentary units in the target block.

9. The method for obtaining the chemical flooding injection-production connection type according to claim 8, characterized in that: In step S6, the thickness of the single layer, the number of connected directions and the ratio of the thickness of the thin and thick layers are considered, and the connectivity coefficient E is applied. 井组 The well group connectivity type is determined, and the calculation formula is: Among them, h 单层碾平i is the thickness of single layer development, η 厚度比例i is the thickness ratio, E 井组连通系数 is the well group connectivity coefficient, h 连通井i is the effective thickness of the center well, k i is the number of connected directions of the central well on sedimentary unit i; h 连通井i is the effective thickness of the oil well connected to the central well, m; m is the number of sedimentary units.

10. The method for obtaining the chemical flooding injection-production connection type according to claim 9, characterized in that: The principle for judging the well group connectivity type is: 井组连通系数 When E ≤0.3, the well group belongs to the thin injection and thick production type; 井组连通系数 ≥3, the well group belongs to the thick injection and thin production type; when 0.3 <E 井组连通系数 <3, and the thickness of oil and water wells is relatively large, the well group belongs to the thick injection and thick production type; when 0.3 <E 井组连通系数 <3, and the development of oil and water wells is poor, the well group belongs to the thin injection and thin production type.

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