A method for optimizing and adjusting injection and production parameters during oil reservoir water injection development

Abstract

The present invention provides a method for optimizing and adjusting injection and production parameters during the water injection development process of an oil reservoir, the method comprising: dividing the oil reservoir into zones, determining the main controlling factors within each zone, the development technical parameters under different main controlling factors, and the development rules; determining the main controlling factors, development targets, and current indicators of development technical parameters for each injection and production well group; determining the well group and development target that require injection and production adjustment based on the reasonable indicators of the development target and the current indicators of the injection and production well group; adjusting the injection and production well group according to the range of development technical parameters; repeating the above steps to complete the optimization and adjustment of injection and production parameters at different development stages. The present invention clarifies the development target and reasonable development technical parameters under each main controlling factor by dividing the main controlling factor area, and determines the injection and production well group that requires adjustment by comparing it with the current indicators of the injection and production well group. Then, by optimizing and adjusting the injection and production parameters, the oil reservoir is exploited normally in the direction of the control target, thereby improving the development effect of the oil reservoir.

Description

Technical Field

[0001] The invention belongs to the technical field of oil reservoir development and relates to a method for optimizing and adjusting injection and production parameters during the water injection development process of an oil reservoir. Background Art

[0002] As an important fossil energy source in today's society, petroleum is essential for every step, from oilfield exploration and production to subsequent production and processing. Once an oil reservoir is mined, the key issue that must be addressed is whether it can be effectively developed. Oil reservoirs are generally developed through water injection based on their component characteristics. The extraction of oil reservoirs is closely related to the geological environment in which they are located. The complex characteristics of the geological environment make the development of oil reservoirs more difficult, and therefore an understanding of the corresponding geological characteristics is also required. Due to the different geological characteristics and oil content in different areas of the reservoir, once the reservoir is fully water-flooded, the implementation of reasonable development technology is the key to ensuring efficient reservoir development. The optimization and adjustment of injection and production parameters need to be carried out throughout the entire life cycle of the reservoir development.

[0003] Different types of reservoirs will affect the choice of development technology. For heterogeneous reservoirs, corresponding reasonable technical solutions should be implemented at different stages of reservoir water injection development. Taking complex porosity carbonate reservoirs as an example, this type of reservoir has strong planar and interlayer heterogeneity, and complex geological features such as high permeability layers, fractures, asphalt layers, and interlayers are widely developed. After the reservoir is water-injected for development, if inappropriate water injection development technical policies are implemented, it will lead to premature breakthrough of injected water and premature flooding of production wells. After water breakthrough, the water cut of the oil wells will increase rapidly and the production will decrease significantly. Most reservoirs will face development challenges such as high water cut and low recovery rate. For reservoirs entering the long-term water injection development stage, the reservoir well network is basically determined and the well locations are generally fully deployed. It is difficult to continue to add new wells. The optimization of development effects can basically only rely on measures and adjustments to injection and production parameters to optimize development effects.

[0004] Optimizing injection and production parameters does not require changes to the well pattern, is simple to operate, and does not require any additional measures or construction costs. It is also a currently widely used method for optimizing development effects. CN 110288258A discloses a method for tapping the potential of remaining oil in high-water-cut reservoirs. The method includes: analyzing the main geological controlling factors of the flow field in different reservoirs to determine a quantitative characterization method for the reservoir flow field, and then determining the initial flow field distribution pattern and pattern. Then, combining development dynamics and other late-stage oilfield development data to analyze the dominant flow field distribution pattern and pattern, and finally using the dominant flow field-initial flow field difference method to find and recover the remaining oil. This method mainly compares the initial flow field with the dominant flow field and utilizes the difference between the two to recover the remaining oil. It does not cover the entire process of reservoir development and does not clearly define how to adjust injection and production parameters during the reservoir development process.

[0005] CN 106351624A discloses a method for improving oil recovery by zoning control of fault-block reservoirs in the ultra-high water-cut stage. The method comprises: analyzing the structural geological characteristics and well pattern evolution characteristics of the study area; conducting a reasonable zoning study by studying the complex remaining oil characteristics and influencing factors; comprehensively formulating a zoning scheme for complex fault-block reservoirs in the ultra-high water-cut stage by analyzing the differences in planar water flooding effects and influencing factors of typical fault-block reservoirs; using numerical simulation means or reservoir engineering methods to clarify the development contradictions of each zone, optimize the zoning control technology policy, and carry out the optimization design of the zoning injection-production control scheme; the method focuses on zoning specific fault-block reservoirs to regulate the injection-production scheme separately, but it is also aimed at the later stage of exploitation of specific oil reservoirs, has a narrow scope of application, involves fewer main controlling factors, and does not involve the selection of development targets or the summary of development laws.

[0006] In summary, for the exploitation of heterogeneous oil reservoirs, it is also necessary to form a set of injection and production parameter optimization and adjustment technologies throughout the life cycle of water injection development based on the characteristics of the reservoir to ensure the development effect of the reservoir. Summary of the Invention

[0007] In response to the problems existing in the prior art, the purpose of the present invention is to provide a method for optimizing and adjusting injection and production parameters during the water injection development process of an oil reservoir. The method clarifies the development objectives and reasonable development technical parameters under each main controlling factor by dividing the oil reservoir into areas, and determines the injection and production well groups and development objectives that need to be adjusted by comparison with the current indicators of the injection and production well groups. Then, by optimizing and adjusting the injection and production parameters, the oil reservoir is exploited normally in the direction of the control target, and real-time adjustments are made according to different development stages, which can continuously improve the development effect of the oil reservoir.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for optimizing and adjusting injection and production parameters during the water flooding development process of an oil reservoir, the method comprising the following steps:

[0010] (1) Divide the reservoir into zones according to its location, determine the main controlling factors affecting the waterflooding development effect of the reservoir in each zone, the development technical parameters for given development targets under different main controlling factors, and the development rules under different main controlling factors;

[0011] (2) Divide the entire reservoir into injection and production well groups, and determine the main controlling factors, current indicators of development goals, and current indicators of development technical parameters for each injection and production well group;

[0012] (3) Determine reasonable indicators of development targets under different main controlling factors of the entire reservoir, and based on the current indicators of the injection and production well groups in step (2), determine the well groups that need injection and production adjustments and their development targets that need to be adjusted;

[0013] (4) adjusting the well group that needs injection and production adjustment selected in step (3) according to the range of development technical parameters determined in step (1) to reach a reasonable technical parameter range;

[0014] (5) According to the frequency of injection and production parameter optimization and adjustment, steps (1) to (4) are repeated to complete the optimization and adjustment of injection and production parameters at different development stages of the reservoir.

[0015] In the present invention, the development of oil reservoirs is a prerequisite for the utilization of petroleum resources, so its development effect is particularly important. Due to the complexity of the geological environment in which the oil reservoirs are located, it is difficult to complete the exploitation process by keeping the injection and production technology and parameters unchanged. The development process of the oil reservoir is a process of continuous optimization and adjustment of the injection and production parameters. In the present invention, the distribution of the oil reservoirs is first divided into zones, and different main controlling factor zones are divided in each zone. Based on the main controlling factors, its development goals and reasonable development technical parameters are clarified, and the development rules are derived in turn. According to the division of the injection and production well groups of the basic units of the oil reservoir, the main controlling factors of the injection and production well groups and their current development indicators are clarified. The reasonable indicators of the development target under the same main controlling factors are compared with the current indicators to determine the injection and production well groups and development targets that need to be adjusted. Optimization and adjustment are made within a reasonable range of development technical parameters to ensure normal development of the reservoir towards the control target. The above process is carried out in real time at different stages of reservoir development. According to different development stages, reasonable development targets and development technical parameters are re-determined, and injection and production parameters of the injection and production well groups are optimized and adjusted in real time, forming a technology for optimizing and adjusting injection and production parameters throughout the life cycle of reservoir waterflood development to ensure the development effect of the reservoir. The method is flexible in operation, less affected by subjective factors, and can be used for the development of different types of reservoirs.

[0016] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0017] As a preferred technical solution of the present invention, the reservoir is divided into zones according to geographical location in step (1), and each zone is further divided into regions with different main controlling factors.

[0018] Preferably, the main controlling factors in step (1) are determined by combining dynamic and static methods, and injection and production well groups under different main controlling factors have different development effects.

[0019] Preferably, the main controlling factors in step (1) include any one or a combination of at least two of a high permeability layer, a fracture zone, high viscosity oil, bottom water or a well trajectory, preferably a high permeability layer, a combination of a high permeability layer and a fracture zone, a combination of a high permeability layer and high viscosity oil, and a combination of a high permeability layer and bottom water.

[0020] In the present invention, the main controlling factors of oil reservoir development are mainly geological reservoir factors, but also include other factors such as fluid and development methods. Geological factors are factors related to heterogeneity, such as high permeability layers, fracture zones, high-viscosity oil, bottom water and other major factors. They also include the drilling horizon, well trajectory, effective length of the horizontal section, vertical distance between injection and production wells, AB point location of horizontal injection and production wells, and inter-well connectivity.

[0021] Taking a heterogeneous carbonate reservoir in a certain oil field as an example, according to the production situation of each well group in water injection development and the law of water content rising, high permeability layer, high permeability layer + high viscosity oil, high permeability layer + fracture zone, high permeability layer + bottom water and the matching relationship between well trajectory and high permeability layer are the main controlling factors affecting the law of water content rising. However, since the matching relationship between well trajectory and high permeability layer is relatively scattered, it is difficult to study it as a whole. In this paper, the four main controlling factors of high permeability layer, high permeability layer + high viscosity oil, high permeability layer + fracture zone and high permeability layer + bottom water are analyzed, and their distribution in the reservoir block is shown as follows. Figure 1 shown.

[0022] In this study, different controlling factors influence the production and water-cut rise patterns of well groups differently. By comparing and categorizing the production and water-cut changes in oil wells based on their production dynamics, and combining them with dynamic and static factors, we can identify the controlling factors influencing waterflooding. For example, in the initial stages of waterflooding, wells in fractured zones with bottom water see water upon drilling, causing a rapid rise in water cut and resulting in sudden flooding. In wells in high-permeability zones, oil wells experience rapid flooding after water injection from the corresponding water wells, leading to a slow rise in water cut. When the water injection enters the mid-term stage, although the well group in the fracture zone + bottom water is mainly affected by the bottom water, the influence of the surrounding injected water also gradually becomes prominent. The well group in the high permeability layer shows different water content change patterns due to the differences in the well trajectories passing through the high permeability layer. The water content of some oil wells continues to rise, the water content of some oil wells remains stable, and the water content of a small number of oil wells decreases slightly. Then, a relationship is established between the static factor label and the water injection development law of the single well / well group to determine the main controlling factors affecting the water injection development effect of the single well, and fine calibration and division are carried out on the injection and production well network deployment map to determine the main controlling factors of the partition.

[0023] As a preferred technical solution of the present invention, the oil reservoir water injection development in step (1) is divided into different development stages, and the development objectives and development technical parameters of different development stages need to be determined.

[0024] Preferably, the development stages are divided according to the water content or the degree of recovery.

[0025] In the present invention, according to the division of the oil reservoir development stages, it can be divided into a low water content stage, a medium water content stage and a high water content stage, or divided into a low recovery degree stage, a medium recovery degree stage and a high recovery degree stage.

[0026] As a preferred technical solution of the present invention, the development target in step (1) includes any one or a combination of at least two of the water cut increase rate, production decline rate, pressure maintenance degree or pressure recovery rate. Typical but non-limiting examples of the combination include: a combination of water cut increase rate and production decline rate, a combination of production decline rate and pressure maintenance degree, a combination of water cut increase rate, pressure maintenance degree and pressure recovery rate, etc.

[0027] Preferably, the development technical parameters in step (1) include any one or a combination of at least two of the following: injection-production ratio, production pressure difference, oil production rate, maximum injection volume, minimum injection volume, maximum production volume, minimum production volume or maximum gas-oil ratio, wherein the maximum and minimum injection volumes or the maximum and minimum production volumes usually coexist, and the technical parameters are not limited to the above-mentioned options.

[0028] Preferably, the development technical parameters in step (1) are obtained by actual production dynamic data analysis and / or numerical simulation research.

[0029] In the present invention, after clarifying the main controlling factors of the zoning, it is necessary to formulate optimization targets for different development stages and production conditions, that is, the control targets in the development process; for example, in the low water-cut stage, the main target is to maintain and restore the reservoir pressure, while taking into account the control of the rapid increase of water cut; in the high water-cut stage, the target is to control the rapid increase of water cut and restore the reservoir pressure.

[0030] In the present invention, numerical simulation research is used as a method to obtain development technical parameters. The reasonable reservoir pressure under different main controlling factors is determined by numerical simulation research. With the pressure maintenance level as a variable, the changes in technical parameters with development goals are studied, and the cumulative oil production and final water cut of the corresponding production wells are obtained. The reasonable reservoir pressure maintenance level and reservoir pressure in different main controlling factor areas are obtained as the target value for subsequent pressure recovery.

[0031] At present, the most widely used method is the dynamic data analysis method. The reasonable development technical parameters under each main controlling factor in different development stages are determined by using regression formulas based on a large amount of actual dynamic data analysis. First, the discrete data points of the injection-production ratio, water cut increase rate and pressure recovery rate under different main controlling factor well groups are statistically analyzed, and the trend line + interval average processing method is adopted. The monthly or quarterly scattered data points are more centered after interval averaging processing, so as to determine the relationship between the injection-production ratio, water cut increase rate and pressure recovery rate in different main controlling factor areas with more reliable regression coefficients. The reasonable injection-production ratio range of different main controlling factor well groups is determined based on the minimum allowable pressure maintenance level and the maximum water cut increase rate, and then the reasonable value of the injection-production ratio of the subdivided unit is determined according to different pressure levels and different water cut stages.

[0032] Based on historical production performance data, the water cut rise rate, static and flowing pressure levels, etc. of all injection and production well groups are determined. These are then compared with the reasonable technical parameter limits of the injection and production well groups under different main controlling factors to clarify the injection and production parameter limits for the injection and production well groups to maintain pressure without drop and control water cut rise within a reasonable range.

[0033] Taking a heterogeneous carbonate reservoir in a certain oilfield as an example, the relationship between the water cut increase rate, pressure recovery rate and injection-production ratio under different main controlling factors obtained by the above method is shown in Table 1, as well as the reasonable injection-production ratio range. The reasonable injection-production ratio range under different pressure and water cut conditions is further subdivided and shown in Table 2.

[0034] Table 1 Relationship between water cut rise rate, pressure recovery rate and injection-production ratio and reasonable injection-production ratio range

[0035]

[0036]

[0037] Table 2 Reasonable injection-production ratio range under different pressure and water content conditions

[0038]

[0039] As a preferred technical solution of the present invention, the representation form of the development law in step (1) includes any one of the relationship curve between water content and recovery degree, water content increase rate curve, production decline law curve or pressure change law curve, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of the relationship curve between water content and recovery degree and the water content increase rate curve, a combination of the water content increase rate curve and the production decline law curve, a combination of the water content increase rate curve, the production decline law curve and the pressure change law curve, etc.

[0040] As a preferred technical solution of the present invention, the horizontal wells in the oil reservoir in step (2) are arranged in a row-like well pattern.

[0041] Preferably, the injection-production well group in step (2) is the smallest injection-production unit, and each injection-production well group includes an injection well and a production well.

[0042] In the present invention, the injection wells are water injection wells, the production wells are oil production wells, and the horizontal wells are arranged alternately in rows of injection wells and production wells.

[0043] As a preferred technical solution of the present invention, the main controlling factor of the injection-production well group in step (2) is determined by the main controlling factor area determined in step (1) where the injection-production well group is located.

[0044] Preferably, the current indicators of the development objectives and development technical parameters in step (2) are derived from current production data.

[0045] In the present invention, some current indicators of the development technical parameters, such as the injection-production ratio, can be directly obtained, while some parameters, such as the maximum and minimum production of production wells and the maximum and minimum injection volumes of injection wells, can be determined by production capacity evaluation methods such as inflow and outflow dynamic curves.

[0046] As the production conditions and injection volume of the well groups change, the flow direction and diversion rate of injected water between well groups are not static. Auxiliary evaluation can be performed based on dynamic connectivity evaluation or diversion rate results of streamline numerical simulation to calculate a more accurate injection-production ratio, and optimization and adjustment can be made on this basis.

[0047] As a preferred technical solution of the present invention, the reasonable index of the development target in step (3) adopts the average index of the current development, or the reasonable index corresponding to the development law obtained in step (1) is reversely deduced.

[0048] Preferably, the average development index currently comprises the average development index of the entire reservoir or the average development indexes of each under different main controlling factors, preferably the average development indexes of each under different main controlling factors.

[0049] Preferably, the current indicators of the development target in step (2) are compared with the reasonable indicators in step (3), and the injection and production well group with poor current indicators is determined to be the well group that needs injection and production adjustment. The injection and production well group with poor current indicators includes the injection and production well group that obviously deviates from the development law of step (1) or the development indicators have obviously deteriorated.

[0050] Preferably, the development target corresponding to the poor current indicator is the development target that needs to be adjusted for the injection and production well group.

[0051] As a preferred technical solution of the present invention, the deviation of the development target in step (4) is achieved by adjusting the injection and production parameters to achieve reasonable indicators of the development target, and the injection and production parameters are adjusted within the range of reasonable technical parameters.

[0052] Preferably, the adjusted injection-production parameters include the injection rate of the injection well or the liquid production rate of the production well in the injection-production well group.

[0053] In the present invention, the adjustment of the development indicators of the injection-production well group requires a clear adjustment target and is carried out within the range of reasonable technical parameters. For example, if the water cut rise rate is used as the control target, if the water cut rise rate is too fast, the injection-production ratio needs to be controlled and the lower limit of the reasonable injection-production ratio needs to be adjusted; if the current injection-production ratio is already at the lower limit of the reasonable injection-production ratio, the injection-production ratio will be further reduced. In the next adjustment, attention will be paid to whether the pressure is still within the reasonable control range, and then further consideration will be given to how to adjust the injection-production ratio; if the pressure is used as the control target, when the current pressure is low, the injection-production ratio needs to be increased, and the upper limit of the reasonable injection-production ratio needs to be adjusted; if the current injection-production ratio is already at the upper limit of the reasonable injection-production ratio, the injection-production ratio will be further increased. In the next adjustment, attention will be paid to whether the water cut rise rate is still within the reasonable control range, and then further consideration will be given to how to adjust the injection-production ratio.

[0054] As a preferred technical solution of the present invention, the frequency of optimizing and adjusting the injection and production parameters in step (5) is quarterly, monthly, weekly or daily.

[0055] Preferably, in different development stages, the reasonable development objectives and reasonable development technical parameters under the same main controlling factors are different, and the current indicators of the injection and production well groups will also be different, and steps (1) and (2) will be continuously optimized.

[0056] Preferably, based on the optimized steps (1) and (2), the injection and production well groups that need to be adjusted are re-determined, and their injection and production parameters are optimized.

[0057] In the present invention, the optimization of the injection and production parameters is carried out throughout the entire process of reservoir water injection development. Therefore, a suitable frequency of optimization adjustment is selected according to the actual injection and production development process. As the reservoir development continues, the reasonable development technical parameters will change, and the corresponding adjustment of the injection and production well group also needs to be carried out in real time.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The method of the present invention clarifies the development objectives and reasonable development technical parameters under each major controlling factor by dividing the reservoir into regions. By comparing the parameters with the current indicators of the injection-production well group, the injection-production well group and the development objectives that need to be adjusted are determined. Then, by optimizing and adjusting the injection-production parameters, the reservoir is produced normally in the direction of the control target. By making real-time adjustments according to different development stages, the development effect of the reservoir can be continuously improved, and the average annual recovery rate can be increased by about 0.2%;

[0060] (2) The method of the present invention is flexible to operate, is less affected by subjective factors, and can be used for the development of different types of oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1The distribution of the main controlling factors in the heterogeneous carbonate reservoir block provided by the present invention;

[0062] Figure 2 is a relationship diagram between the water cut increase rate of the entire reservoir and the injection-production ratio provided in Example 1 of the present invention;

[0063] Figure 3 is a relationship diagram between the full reservoir pressure recovery rate and the injection-production ratio provided in Example 1 of the present invention;

[0064] Figure 4 This is a comparison chart of the pressure maintenance level data of each well group provided in Example 1 of the present invention and the reasonable pressure maintenance level;

[0065] Figure 5 This is a comparison chart of the water cut of each well group and the upper limit of the reasonable water cut provided in Example 1 of the present invention;

[0066] Figure 6 This is the injection-production parameter optimization process of a certain well group with a water cut to be optimized provided in Example 1 of the present invention;

[0067] Figure 7 The water cut rising rate curve and the pressure recovery rate curve during the injection-production parameter optimization process of a certain water cut well group to be optimized provided in Example 1 of the present invention;

[0068] Figure 8 The production performance curve of a certain water cut optimization well group provided in Example 1 of the present invention;

[0069] Figure 9 This is a graph showing the change in water cut increase rate before and after full reservoir optimization provided in Example 1 of the present invention;

[0070] Figure 10 This is the pressure recovery condition after full reservoir optimization provided by Example 1 of the present invention. DETAILED DESCRIPTION

[0071] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention is further described in detail below. However, the following embodiments are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0072] The specific embodiment of the present invention provides a method for optimizing and adjusting injection and production parameters during the water flooding development of an oil reservoir, the method comprising the following steps:

[0073] (1) Divide the reservoir into zones according to its location, determine the main controlling factors affecting the waterflooding development effect of the reservoir in each zone, the development technical parameters for given development targets under different main controlling factors, and the development rules under different main controlling factors;

[0074] (2) Divide the entire reservoir into injection and production well groups, and determine the main controlling factors, current indicators of development goals, and current indicators of development technical parameters for each injection and production well group;

[0075] (3) Determine reasonable indicators of development targets under different main controlling factors of the entire reservoir, and based on the current indicators of the injection and production well groups in step (2), determine the well groups that need injection and production adjustments and their development targets that need to be adjusted;

[0076] (4) adjusting the well group that needs injection and production adjustment selected in step (3) according to the range of development technical parameters determined in step (1) to reach a reasonable technical parameter range;

[0077] (5) According to the frequency of injection and production parameter optimization and adjustment, steps (1) to (4) are repeated to complete the optimization and adjustment of injection and production parameters at different development stages of the reservoir.

[0078] The following are typical but non-limiting examples of the present invention:

[0079] Example 1:

[0080] This embodiment provides a method for optimizing and adjusting injection and production parameters during oil reservoir water flooding development, the method comprising the following steps:

[0081] (1) Taking a heterogeneous carbonate reservoir as an example, the reservoir is divided into zones according to its geographical location, and the main controlling factors affecting the water injection development effect of the reservoir in each zone are determined, as well as the development technical parameters for given development targets under different main controlling factors and the development rules under different main controlling factors.

[0082] The main controlling factors are determined by combining dynamic and static methods. Different injection and production well groups under different main controlling factors have different development effects. The main controlling factors include high permeability layers, the combination of high permeability layers and fracture zones, the combination of high permeability layers and high-viscosity oil, and the combination of high permeability layers and bottom water.

[0083] The water injection development of the oil reservoir is divided into different development stages. The development objectives and development technical parameters of each development stage must be determined. The development stages are divided according to the water cut. The development objectives include the water cut increase rate and the pressure maintenance level. The development technical parameters include the injection-production ratio.

[0084] The reasonable injection-production ratio range is obtained through the regression formula under actual dynamic data analysis. First, the injection-production ratio, water cut increase rate and pressure recovery rate under different main controlling factors are statistically analyzed for discrete data points. The trend line + interval average processing method is adopted to determine the relationship between the injection-production ratio, water cut increase rate and pressure recovery rate in different main controlling factors. The reasonable injection-production ratio range of different main controlling factors well groups is determined by the minimum allowable pressure maintenance level and the maximum water cut increase rate. Then, the reasonable injection-production ratio values ​​of the units are subdivided according to different pressure levels and different water cut stages. The specific data results are shown in Tables 1 and 2.

[0085] Among them, taking the relationship between the water cut increase rate and the injection-production ratio, and the pressure recovery rate and the injection-production ratio in the entire reservoir as an example, the process of the trend line + interval average processing method is explained: first, according to the current development stage and production data, a scatter plot of the water cut increase rate and the injection-production ratio is obtained. The interval range is large due to factors such as the water cut monitoring cycle and measurement error, but there is an obvious law that the water cut increase rate increases with the increase of the injection-production ratio. By controlling the injection-production ratio interval step size at 0.1, when the data points are less than 5, the injection-production ratio and the water cut increase rate are both averaged. When the data points are greater than 5, the step size can be subdivided and the average is taken for up to 5 data points, thereby obtaining the mean plot and relationship formula of the water cut increase rate and the injection-production ratio. The specific results are as follows: Figure 2 The relationship between water cut rise rate and injection-production ratio is shown in the graph;

[0086] Similarly, we obtain the scatter plot of pressure recovery rate and injection-production ratio. Since the pressure measurement point data of the well group in the main controlling factor area are relatively small, the pressure recovery rate and injection-production ratio have a relatively obvious regularity after the quarterly data scatter plot statistics. However, due to the lack of monitoring well points, the distribution interval is relatively large. We can take the average according to the concentrated interval of the data points, and then obtain the relationship formula between the pressure recovery rate and injection-production ratio. The specific results are as follows: Figure 3 The relationship between pressure recovery rate and injection-production ratio is shown in the figure;

[0087] (2) Dividing the entire reservoir into injection and production well groups, wherein the horizontal wells in the reservoir are arranged in a row-like well pattern, wherein the injection and production well group is the smallest injection and production unit, and each injection and production well group includes an injection well and a production well, and determining the main controlling factors, current indicators of development targets, and current indicators of development technical parameters for each injection and production well group; the main controlling factors of the injection and production well group are determined by the main controlling factor area determined in step (1) where the injection and production well group is located; and the current indicators of development targets and development technical parameters are derived from current production data;

[0088] (3) determining reasonable indicators of development targets under different main controlling factors of the entire reservoir, wherein the reasonable indicators of the development targets adopt the current average development indicators under different main controlling factors; based on the current indicators of the injection-production well group in step (2), comparing them with the reasonable indicators, determining the well group that needs to be adjusted for injection and production and the development targets that need to be adjusted, wherein the injection-production well group with worse current indicators is the well group that needs injection and production adjustment, and the development targets corresponding to the worse current indicators are the development targets that need to be adjusted for the injection-production well group;

[0089] Among them, the existing production dynamic data is compared and analyzed on a monthly basis to identify the well groups that need to be optimized and adjusted and the degree of their deviation from the target, and their injection and production parameters are adjusted; the comparison chart of the pressure maintenance level data of each well group and the reasonable pressure maintenance level is as follows Figure 4 As shown, the pressure wells to be optimized are determined and the screening of abnormal pressure recovery well points is completed; the comparison chart of the water cut of each well group and the upper limit of the reasonable water cut is shown in Figure 5 As shown, the water cut wells to be optimized are determined and the screening of well points with abnormal water cut increase rate is completed;

[0090] (4) adjusting the well group that needs injection and production adjustment selected in step (3) according to the range of development technical parameters determined in step (1) to reach a reasonable technical parameter range; the deviation of the development target of the injection and production well group to be adjusted is achieved by adjusting the injection and production parameters to achieve a reasonable indicator of the development target, and the injection and production parameters are adjusted within the reasonable technical parameter range;

[0091] Taking the above-mentioned well group with water content to be optimized as an example, the optimization process of its injection and production parameters is as follows: Figure 6 As shown in the figure, the water cut rising rate curve and pressure recovery rate curve in the parameter optimization process are as follows: Figure 7 As shown in Figure 1, when the water cut increased significantly, the injection-production ratio was lowered to control the water cut increase rate. The injection-production ratio was then appropriately increased to maintain around 1.0. After the adjustment, the pressure showed an upward trend, and the water cut did not increase significantly, indicating that the injection-production optimization adjustment had a good effect. The production performance curve of the well group is shown in Figure 1. Figure 8 As shown in Figure 2, it can be further reflected that after the optimization of injection-production ratio began, the measured water cut generally decreased;

[0092] (5) According to the frequency of injection and production parameter optimization and adjustment, which is monthly, repeat steps (1)-(4) to complete the optimization and adjustment of injection and production parameters at different development stages of the reservoir; in different development stages, the reasonable development goals and reasonable development technical parameters under the same main controlling factors are different, and the current indicators of the injection and production well group will also be different. Continuously optimize steps (1) and (2), and based on the optimized steps (1) and (2), re-determine the injection and production well group that needs to be adjusted and optimize its injection and production parameters;

[0093] After this adjustment of the well group to be optimized in the entire reservoir, the comprehensive water content of the reservoir has been controlled, and the changes in the water content increase rate are as follows: Figure 9 As shown in the figure, the pressure recovery of the reservoir is controlled from 7.9% before adjustment to -2.3%. Figure 10 As shown in the figure, after adjustment, the reservoir pressure recovered to 259 psi, achieving a good effect of controlling water and stabilizing oil production.

[0094] From the above embodiments, it can be seen that the method of the present invention clarifies the development objectives and reasonable development technical parameters under each main controlling factor by dividing the area of ​​the oil reservoir, and determines the injection and production well group and development objectives that need to be adjusted by comparison with the current indicators of the injection and production well group. Then, by optimizing and adjusting the injection and production parameters, the oil reservoir is exploited normally in the direction of the control target, and according to the above process and method, real-time adjustments are made according to different development stages, which can continuously improve the development effect of the oil reservoir. The method is flexible in operation, less affected by subjective factors, and can be used for the development of different types of oil reservoirs.

[0095] While the present invention uses the above-described embodiments to illustrate the detailed methods of the present invention, the present invention is not limited to the above-described detailed methods, nor does it necessarily rely on the above-described detailed methods for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the methods of the present invention, additions of auxiliary steps, and selections of specific methods are all within the scope of protection and disclosure of the present invention.

Claims

1. A method for optimizing and adjusting injection and production parameters during water flooding development of oil reservoirs, characterized in that: The method comprises the following steps: (1) Divide the reservoir into zones according to its location, determine the main controlling factors affecting the waterflooding development effect of the reservoir in each zone, the development technical parameters for given development targets under different main controlling factors, and the development rules under different main controlling factors; The main controlling factors include any one or a combination of at least two of the following: high permeability layer, fracture zone, high viscosity oil, bottom water or well trajectory; the development objectives include any one or a combination of at least two of the following: water cut increase rate, production decline rate, pressure maintenance degree or pressure recovery rate; the representation form of the development law includes any one or a combination of at least two of the following: a water cut and recovery degree relationship curve, a water cut increase rate curve, a production decline law curve or a pressure change law curve; (2) Divide the entire reservoir into injection and production well groups, and determine the main controlling factors, current indicators of development goals, and current indicators of development technical parameters for each injection and production well group; (3) Determine reasonable indicators of development targets under different main controlling factors of the entire reservoir, and based on the current indicators of the injection and production well groups in step (2), determine the well groups that need injection and production adjustments and their development targets that need to be adjusted; The reasonable index of the development target adopts the average index of the current development, or the reasonable index corresponding to the development law obtained in step (1); (4) adjusting the well group that needs injection and production adjustment selected in step (3) according to the range of development technical parameters determined in step (1) to achieve a reasonable technical parameter range; the deviation of the development target is achieved by adjusting the injection and production parameters to achieve a reasonable indicator of the development target, and the injection and production parameters are adjusted within the reasonable technical parameter range; (5) According to the frequency of injection and production parameter optimization and adjustment, steps (1) to (4) are repeated to complete the optimization and adjustment of injection and production parameters at different development stages of the reservoir.

2. The method according to claim 1, characterized in that The reservoirs in step (1) are divided into zones according to geographical locations, and each zone is further divided into areas with different main controlling factors.

3. The method according to claim 1, characterized in that The determination of the main controlling factors in step (1) is achieved through a combination of dynamic and static methods. Injection and production well groups under different main controlling factors have different development effects.

4. The method according to claim 1, wherein The main controlling factors in step (1) are the high permeability layer, the combination of the high permeability layer and the fracture zone, the combination of the high permeability layer and high viscosity oil, and the combination of the high permeability layer and bottom water.

5. The method according to claim 1, wherein The reservoir water injection development in step (1) is divided into different development stages, and the development objectives and development technical parameters of different development stages need to be determined.

6. The method according to claim 5, characterized in that The development stages are divided according to the water content or the degree of recovery.

7. The method according to claim 1, characterized in that The development technical parameters in step (1) include any one or a combination of at least two of the following: injection-production ratio, production pressure difference, oil production rate, maximum injection volume, minimum injection volume, maximum production volume, minimum production volume or maximum gas-oil ratio.

8. The method according to claim 1, characterized in that The development technical parameters described in step (1) are obtained through actual production dynamic data analysis and / or numerical simulation research.

9. The method according to claim 1, characterized in that The horizontal wells in the oil reservoir in step (2) are arranged in a row well pattern.

10. The method according to claim 1, characterized in that The injection-production well group in step (2) is the smallest injection-production unit, and each injection-production well group includes an injection well and a production well.

11. The method according to claim 1, wherein The main controlling factors of the injection-production well group in step (2) are determined by the main controlling factor area determined in step (1) where the injection-production well group is located.

12. The method according to claim 1, characterized in that The current indicators of the development objectives and development technical parameters in step (2) are derived from current production data.

13. The method according to claim 1, wherein The average development index of the current development in step (3) includes the average development index of the entire reservoir or the average development index of each under different main controlling factors.

14. The method according to claim 13, wherein: The average indicators currently developed are the average development indicators of each under different main controlling factors.

15. The method according to claim 1, wherein Compare the current indicators of the development target in step (2) with the reasonable indicators in step (3) to determine the injection-production well group with the worse current indicators as the well group that needs injection-production adjustment.

16. The method according to claim 15, characterized in that The development target corresponding to the poor current indicator is the development target that needs to be adjusted for the injection and production well group.

17. The method according to claim 1, wherein The injection and production parameters adjusted in step (4) include the injection rate of the injection wells or the liquid production rate of the production wells in the injection and production well group.

18. The method according to claim 1, wherein The frequency of optimizing and adjusting the injection and production parameters in step (5) is quarterly, monthly, weekly or daily.

19. The method according to claim 1, wherein In different development stages, the reasonable development goals and reasonable development technical parameters under the same main controlling factors are different, and the current indicators of the injection and production well group will also be different, and steps (1) and (2) will be continuously optimized.

20. The method according to claim 1, wherein Based on the optimized steps (1) and (2), the injection and production well groups that need to be adjusted are re-determined, and their injection and production parameters are optimized.

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