Establishment and application of injection-production well adjustment chart for three types of oil reservoirs in water flooding stage

Abstract

The application relates to a kind of three types of oil layer blank water drive stage injection-production well adjustment chart establishing method, and relates to the field of tertiary oil recovery of three types of oil layer, solves the problem that existing three types of oil layer is obviously different from type 1 oil layer and cannot be completely applied to type 1 oil layer tracking adjustment technology.The method comprises the establishing method of injection well and production well adjustment chart;the establishing method of injection well adjustment chart comprises: taking injection-production ratio of injection well as the length of rectangle, the length range is 0-1.4, taking pressure space as width, the length range is 0-10, constructing rectangular chart;the chart is divided into five regions, which are reasonable area, speed-up area, fracturing area, speed-down area and speed-down and production control area;the establishing method of production well adjustment chart comprises: taking flow pressure of production well as the length of rectangle, the length range is 0-7.0, taking daily liquid production as width, the length range is 0-50, constructing rectangular chart, and there are four regions on the chart, which are fracturing area, small participation area, reasonable area and large participation area.

Description

Technical Field

[0001] This invention relates to the field of tertiary oil recovery technology for three types of oil reservoirs, and in particular to a method for establishing and using an adjustment chart for injection and production wells in the blank water drive stage of three types of oil reservoirs. Background Technology

[0002] According to the evolution of polymer flooding well networks in oilfields, polymer flooding is first carried out in Class I oil layers, followed by polymer flooding in other oil layers. With the continuous industrialization of Class I oil layers, polymer flooding tracking and adjustment technology has been continuously improved and optimized, forming a polymer flooding matching and adjustment technology suitable for Class I oil layers. Meanwhile, the remaining reserves of Class I oil layers are decreasing year by year. To achieve production succession, the future target of polymer flooding will shift from Class I to Class III oil layers. For example, in the Daqing Oilfield polymer flooding well network, from a sedimentary perspective, there are significant differences between Class I and Class III oil layers. First, the sedimentary environments are significantly different. Class I oil layers are mainly composed of deltaic distributary plain facies sand bodies and deltaic front facies sand bodies, with large-area channel sands developed in the plane, high drilling rate, large effective thickness, high permeability, and relatively homogeneous in the plane and between layers. In contrast, Class III oil layers have more layers, thinner thickness, lower permeability, and severe interlayer heterogeneity. Compared with Class I oil layers, Class III oil layers have poor mobilization during the waterflooding stage, relatively higher remaining oil saturation, and are affected by the waterflooding well network. Type I oil reservoirs have low formation pressure and low injection pressure before polymer injection. Type III oil reservoirs are poorly utilized during the water drive stage, with relatively high formation pressure and high injection pressure due to the influence of oil reservoir development. Moreover, the pressure distribution is uneven in the plane. This uneven pressure system is not conducive to the uniform advancement of polymer, thus affecting the oil displacement effect of polymer. However, since the oil reservoir development of Type III oil reservoirs differs significantly from that of Type I oil reservoirs and the degree of influence from the base wells is different, the existing technology for adjusting the pressure system cannot be fully applied to Type I oil reservoirs. Therefore, it cannot be used to guide the tracking and adjustment of injection and production wells before polymer injection. Summary of the Invention

[0003] This invention addresses the problem in the prior art where the significant differences between existing Class III and Class I oil reservoirs prevent the full application of Class I reservoir tracking and adjustment techniques. It provides a method for establishing an adjustment chart for injection-production wells during the blank waterflooding stage of Class III oil reservoirs. This method guides the tracking and adjustment of injection-production wells before polymer injection, providing a favorable pressure system for the uniform advancement of polymers. This invention also provides a method for using the adjustment chart for injection-production wells during the blank waterflooding stage of Class III oil reservoirs.

[0004] The present invention solves its problems through the following technical solution:

[0005] The first aspect of this invention provides a method for establishing an adjustment chart for injection-production wells in three types of oil reservoir blank water drive stages, comprising the following steps:

[0006] This includes methods for establishing adjustment charts for injection wells and production wells;

[0007] The method for establishing the injection well adjustment chart includes:

[0008] A rectangular diagram is constructed with the injection-production ratio of the injection well as the length of the rectangle, ranging from 0 to 1.4, and the pressure space of the injection well as the width of the rectangle, ranging from 0 to 10, with the unit being MPa.

[0009] The chart is divided into five areas: the rational zone, the acceleration zone, the fracturing zone, the deceleration zone, and the deceleration-controlled mining zone.

[0010] The method for establishing the production well adjustment chart includes:

[0011] A rectangular chart is constructed with the produced well flowing pressure as the length of a rectangle, ranging from 0 to 7.0 MPa, and the daily fluid production as the width of a rectangle, ranging from 0 to 50 tons. The chart contains four regions.

[0012] The diagram is divided into four areas: fracturing zone, low parameter adjustment zone, reasonable parameter adjustment zone, and high parameter adjustment zone.

[0013] Furthermore, regarding the established injection well adjustment chart:

[0014] The rectangular area formed by the long side ranging from 0.9 to 1.1 and the wide side ranging from 4 MPa to 6 MPa is a reasonable area;

[0015] The polygonal region formed by removing the reasonable area from the rectangular region with the long side ranging from 0 to 1.0 and the wide side ranging from 5 MPa to 10 MPa is the speed-up zone.

[0016] The rectangular area with a long side ranging from 0 to 1.0 and a wide side ranging from 0 MPa to 5 MPa, after removing the reasonable area, forms a polygonal area, which is the fracturing zone.

[0017] The rectangular region with a long side ranging from 1.0 to 1.4 and a wide side ranging from 0 MPa to 5 MPa, after removing the reasonable area, forms a polygonal region, which is the deceleration region.

[0018] The rectangular area with a long side ranging from 1.0 to 1.4 and a wide side ranging from 5 MPa to 10 MPa, after removing the reasonable area, forms a polygonal area, which is the rate-reducing and controlled mining area.

[0019] Furthermore, regarding the established production well adjustment chart:

[0020] The rectangular area formed by the long side ranging from 0MPa to 2.0MPa and the wide side ranging from 0t to 25t is the fracturing zone;

[0021] The rectangular region formed by the long side ranging from 0.0MPa to 2.0MPa and the wide side ranging from 25t to 50t is the parameter adjustment region;

[0022] A rectangular area with a long side ranging from 2.0MPa to 5.0MPa and a wide side ranging from 0t to 50t is considered a reasonable range.

[0023] The rectangular region formed by the long side ranging from 5.0MPa to 7.0MPa and the wide side ranging from 0t to 50t is the parameter adjustment region.

[0024] The second aspect of this invention provides a method for using an adjustment chart for injection-production wells in the blank water drive stage of three types of oil reservoirs;

[0025] Based on the constructed injection well adjustment chart and production well adjustment chart, relevant areas are selected and corresponding adjustment methods are applied according to the relevant adjustment parameters.

[0026] Furthermore, based on the constructed injection well adjustment map, and according to the two parameters of the injection-production ratio and the injection well pressure space, relevant areas are selected for corresponding adjustment methods, including the following steps:

[0027] Wells with an injection-production ratio ranging from 0.9 to 1.1 and a pressure range of 4 MPa to 6 MPa are within a reasonable zone of the rectangular area; the current injection parameters should be maintained for wells within the reasonable zone.

[0028] The injection wells with an injection-production ratio ranging from 0 to 1.0 and a pressure range of 5 MPa to 10 MPa are located in the acceleration zone of the polygonal region formed after removing the reasonable area from the rectangular region; the injection wells located in the acceleration zone are accelerated.

[0029] The injection-production ratio of the injection well is in the range of 0-1.0, and the pressure space is in the range of 0MPa-5MPa. The well is located in the fracturing zone of the polygonal area formed after removing the reasonable area from the rectangular area; the injection well located in the fracturing zone is subjected to fracturing.

[0030] For injection wells with an injection-production ratio ranging from 1.0 to 1.4 and a pressure range of 0 MPa to 5 MPa, the injection rate of the well is reduced within the polygonal region formed after removing the reasonable zone from the rectangular region. The injection rate of the injection wells located within the reduced-rate zone is then lowered.

[0031] The injection-production ratio of the injection well is in the range of 1.0-1.4, and the pressure range is in the range of 5MPa-10MPa. The injection well is located in the polygonal area formed after removing the reasonable area from the rectangular area. The injection rate of the injection well in the reduced-rate production zone is adjusted down, and the production rate of the production well is controlled.

[0032] Furthermore, for injection wells located within the acceleration zone, the injection rate is increased. Specifically, for injection wells with an injection-production ratio ≤ 0.9 when the injection pressure space is ≥ 7 MPa, the daily injection volume is increased by 20 m³ / s. 3 When the injection pressure space is ≥7MPa, for injection wells with an injection-production ratio greater than 0.9, the daily injection volume can be increased by 15m³. 3 When the injection pressure space is ≥6MPa and <7MPa, the daily injection volume is increased by 15m. 3 When the injection pressure space is <6MPa, the daily injection volume is increased by 12m. 3 ;

[0033] For injection wells located within the fracturing zone, fracturing is performed using the following methods: for oil layers with a perforation thickness ≥ 1.5m, multi-fracture fracturing is used; for oil layers with a perforation thickness less than 1.5m, conventional fracturing is used.

[0034] The injection rate of injection wells located in the aforementioned deceleration zone is reduced. Specifically, when the injection pressure space is ≥4MPa and <5MPa, the daily injection volume is reduced by 20m³. 3 When the injection pressure space is ≥3MPa and <4MPa, the daily injection volume should be reduced by 15m. 3 When the injection pressure space is <3MPa, the daily injection volume should be reduced by 10m³. 3 ;

[0035] While reducing the injection rate of injection wells located within the reduced-rate production control zone, the production rate of production wells is also controlled. Specifically, when the injection pressure space is ≥8MPa, the daily injection volume is reduced by 25m³. 3 The daily injection volume is reduced by 20m when the injection pressure space is ≥6MPa and <8MPa. The production well is connected to a control fluid volume of 50t. 3 The daily injection volume is reduced by 10m when the injection pressure space is <6MPa. (Note: The original text also mentions a production well with a control fluid volume of 40t, but this seems unrelated to the injection volume and is likely a separate, incomplete sentence.) 3 , connected to the production well to control fluid 30t.

[0036] Furthermore, based on the constructed production well adjustment map, and according to the two parameters of production well flowing pressure and daily fluid production of this well, relevant areas are selected for corresponding adjustment methods, including the following steps:

[0037] Wells with a production pressure range of 0MPa-2.0MPa and a daily fluid production range of 0t-25t are located in a rectangular fracturing zone. Fracturing is performed on the production wells located in the fracturing zone.

[0038] Wells with a production pressure range of 0.0MPa-2.0MPa and a daily fluid production range of 25t-50t are located in the rectangular parameter reduction zone. The production parameters of the production wells located in the parameter reduction zone are adjusted to be smaller.

[0039] Wells with a production pressure range of 2.0MPa-5.0MPa and a daily fluid production range of 0t-50t are located in a reasonable zone within the rectangular area. Production parameters for production wells within this reasonable zone are maintained.

[0040] Wells with a production pressure range of 5.0MPa-7.0MPa and a daily fluid production range of 0t-50t are located in the parameter adjustment zone of the rectangular area. The production parameters of the wells located in the parameter adjustment zone are adjusted to be increased.

[0041] Furthermore, fracturing is performed on the produced wells located in the fracturing zone. Specifically, multi-fracture fracturing is used for oil layers with a perforation thickness ≥ 1.5m, while conventional fracturing is used for oil layers with a perforation thickness less than 1.5m.

[0042] The production parameters of the wells in the reduced parameter zone are adjusted by reducing the following method: for wells with room for reduction in stroke rate, the stroke rate is reduced first; for wells without room for reduction in stroke rate, the stroke is reduced; when none of the above parameters can be met, the well is replaced with a smaller pump.

[0043] The production parameters of the wells in the above-mentioned parameter adjustment zone are increased. The specific method is as follows: for wells with room for increasing stroke rate, the stroke rate is increased first. For wells without room for increasing stroke rate, the stroke length is increased. When the above parameters cannot be met, the well is replaced with a larger pump.

[0044] Furthermore, the production parameters of the wells in the adjusted parameter area include stroke, stroke frequency, and pump diameter;

[0045] The production parameters of the wells produced in the large-scale production area include stroke, number of strokes, and pump diameter.

[0046] The injection-production well adjustment chart for the blank water drive stage of the three types of oil reservoirs in this invention can be directly applied to the blank water drive stage of the three types of oil reservoirs.

[0047] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:

[0048] Given the significant differences between Class III and Class I oil layers, and the inability to directly apply mature tracking and adjustment techniques for Class I layers, this invention provides a tracking and adjustment method for injection-production wells suitable for the blank water drive stage of Class III oil layers. This ensures the availability of a favorable pressure system for polymer injection and establishes an adjustment chart for injection-production wells during the blank water drive stage of Class III oil layers. This chart guides the tracking and adjustment of polymer flooding in Class III oil layers during the blank water drive stage, providing favorable conditions for the uniform advancement of polymers.

[0049] This invention has been applied in the X-zone Class III oil reservoir test area. Based on the injection-production well adjustment chart, a total of 14 injection well scheme adjustments and 4 fracturing operations were completed during the blank water drive stage. The parameters of 3 production wells were increased and the parameters of 10 production wells were decreased. After comprehensive adjustment, the plane distribution of injection pressure is more balanced. The difference in injection pressure between single wells decreased from 6.1 MPa before adjustment to 2.8 MPa. The flowing pressure of production wells increased from 3.08 MPa to 4.93 MPa, an increase of 1.85 MPa.

[0050] Based on field tests in three types of oil reservoirs, the results show that by timely tracking and adjusting injection and production wells, the injection and production in the study area tend to be balanced, the pressure distribution on the plane is more uniform, the maximum pressure difference of single wells is reduced, and the flowing pressure level of the production well is effectively improved, providing a favorable pressure system for the uniform advancement of polymers. The injection and production well chart invented in this paper can be directly applied in the blank water drive stage of three types of oil reservoirs. Attached Figure Description

[0051] Figure 1 Adjusted charts for injection wells in the three types of oil reservoir blank water drive stage established for this invention;

[0052] Figure 2 Adjustment charts for production wells in the three types of oil reservoir blank water drive stage established for this invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] like Figure 1 , Figure 2 As shown, a method for establishing an adjustment chart for injection-production wells in the blank water drive stage of three types of oil reservoirs specifically includes the following steps:

[0055] This includes methods for establishing adjustment charts for injection wells and production wells;

[0056] (1) Method for establishing the injection well adjustment chart;

[0057] like Figure 1 As shown, a rectangular chart is constructed with the injection-production ratio of the injection well as the length of the rectangle, ranging from 0 to 1.4, and the pressure space of the injection well as the width of the rectangle, ranging from 0 to 10, in MPa. The chart is divided into five regions:

[0058] The rectangular area formed by the long side ranging from 0.9 to 1.1 and the wide side ranging from 4 MPa to 6 MPa is the reasonable zone, and the current injection parameters should be maintained for injection wells located within this zone.

[0059] The polygonal region formed by removing the reasonable area from the rectangular region with the long side ranging from 0 to 1.0 and the wide side ranging from 5 MPa to 10 MPa is the acceleration zone. The injection wells located in this region are accelerated.

[0060] A rectangular area with a long side ranging from 0 to 1.0 MPa and a wide side ranging from 0 MPa to 5 MPa, after removing the reasonable zone, forms a polygonal area, which is the fracturing zone. Injection wells located within this zone are then subjected to fracturing.

[0061] The rectangular area with a long side range of 1.0-1.4 and a wide side range of 0MPa-5MPa, after removing the reasonable area, forms a polygonal area, which is the deceleration zone. The injection rate of the injection wells in this area is reduced.

[0062] The rectangular area with a long side range of 1.0-1.4 and a wide side range of 5MPa-10MPa, after removing the reasonable area, forms a polygonal area for rate reduction and production control. The injection rate of the injection wells in this area is reduced, while the production rate of the production wells is controlled.

[0063] (2) Establishment of production well adjustment charts,

[0064] like Figure 2 As shown, a rectangular chart is formed with the produced well flowing pressure as the length of a rectangle, ranging from 0 to 7.0 MPa, and the daily fluid production as the width of a rectangle, ranging from 0 to 50 tons. The chart has four regions:

[0065] The rectangular area formed by the long side ranging from 0MPa to 2.0MPa and the wide side ranging from 0t to 25t is the fracturing zone, and the production wells located in this zone are subjected to fracturing.

[0066] A rectangular area with a long side ranging from 0.0MPa to 2.0MPa and a wide side ranging from 25t to 50t is designated as the parameter reduction zone. Production parameters (stroke, number of strokes, pump diameter) of wells within this zone are reduced.

[0067] A rectangular area with a long side ranging from 2.0MPa to 5.0MPa and a wide side ranging from 0t to 50t is considered a reasonable zone, and production parameters for wells within this zone should be maintained.

[0068] The rectangular area formed by the long side ranging from 5.0MPa to 7.0MPa and the wide side ranging from 0t to 50t is the parameter adjustment zone, and the production parameters (stroke, number of strokes, pump diameter) of the producing wells located in this zone are adjusted to be larger.

[0069] (3) Using injection well adjustment charts to guide comprehensive injection well adjustment methods include:

[0070] ① The chart has five regions. The relevant region is selected based on the injection-production ratio of the injection well and the proportion of pressure rise space.

[0071] ② Adjust the injection rate for injection wells in the acceleration zone.

[0072] ③ Perform fracturing on injection wells located in fracturing zones.

[0073] ④ Reduce the injection rate of wells in the deceleration zone.

[0074] ⑤ For wells in the rate-reduction and controlled production zone, the injection rate should be reduced, and the production rate of connected production wells should also be reduced.

[0075] ⑥ For injection wells in the reasonable zone, the injection parameters should be maintained, and the dynamic changes of the well should be closely monitored. When the well is in other zones, adjustments should be made in a timely manner according to the adjustment chart.

[0076] To accelerate the injection wells located within the acceleration zone, the specific method is as follows: for injection wells with an injection-production ratio ≤ 0.9 and an injection pressure space ≥ 7 MPa, the daily injection volume is increased by 20 m³ / s. 3 When the injection pressure space is ≥7MPa, for injection wells with an injection-production ratio greater than 0.9, the daily injection volume can be increased by 15m³. 3 When the injection pressure space is ≥6MPa and <7MPa, the daily injection volume is increased by 15m. 3 When the injection pressure space is <6MPa, the daily injection volume is increased by 12m. 3 ;

[0077] For injection wells located within the fracturing zone, fracturing is performed using the following methods: for oil layers with a perforation thickness ≥ 1.5m, multi-fracture fracturing is used; for oil layers with a perforation thickness less than 1.5m, conventional fracturing is used.

[0078] The injection rate of injection wells located in the aforementioned deceleration zone is reduced. Specifically, when the injection pressure space is ≥4MPa and <5MPa, the daily injection volume is reduced by 20m³. 3 When the injection pressure space is ≥3MPa and <4MPa, the daily injection volume should be reduced by 15m. 3 When the injection pressure space is <3MPa, the daily injection volume should be reduced by 10m³. 3 ;

[0079] While reducing the injection rate of injection wells located within the reduced-rate production control zone, the production rate of production wells is also controlled. Specifically, when the injection pressure space is ≥8MPa, the daily injection volume is reduced by 25m³. 3 The daily injection volume is reduced by 20m when the injection pressure space is ≥6MPa and <8MPa. The production well is connected to a control fluid volume of 50t. 3The daily injection volume is reduced by 10m when the injection pressure space is <6MPa. (Note: The original text also mentions a production well with a control fluid volume of 40t, but this seems unrelated to the injection volume and is likely a separate, incomplete sentence.) 3 , connected to the production well to control fluid 30t.

[0080] (4) The methods for guiding the comprehensive adjustment of produced wells using the production well adjustment chart include:

[0081] ① The chart has four regions. Select the relevant region based on the well flow pressure and daily fluid production.

[0082] ② Perform fracturing on production wells located in fracturing zones;

[0083] ③ For wells in the low-parameter zone, reduce the production parameters, such as reducing the stroke, number of strokes, or replacing the pump with a smaller one;

[0084] ④ For wells in the production parameters adjustment area, increase the production parameters, increase the stroke, stroke frequency, or replace with a larger pump;

[0085] ⑤ For wells in the reasonable zone, maintain the current production parameters and closely monitor the dynamic changes of the well. When the well is in other zones, make timely adjustments according to the adjustment chart.

[0086] The production wells located in the fracturing zone are subjected to fracturing. Specifically, for oil layers with a perforation thickness ≥ 1.5m, multi-fracture fracturing is used, and for oil layers with a perforation thickness less than 1.5m, conventional fracturing is used.

[0087] The production parameters of the wells in the reduced parameter zone are adjusted by reducing the following method: for wells with room for reduction in stroke rate, the stroke rate is reduced first; for wells without room for reduction in stroke rate, the stroke is reduced; when none of the above parameters can be met, the well is replaced with a smaller pump.

[0088] The production parameters of the wells in the above-mentioned parameter adjustment zone are increased. The specific method is as follows: for wells with room for increasing stroke rate, the stroke rate is increased first. For wells without room for increasing stroke rate, the stroke length is increased. When the above parameters cannot be met, the well is replaced with a larger pump.

[0089] Example 1

[0090] To make the objectives, technical solutions, and advantages of this invention clearer, the following description, using the X-zone Class III oil reservoir test area as an example, will be further detailed with reference to the accompanying drawings.

[0091] This invention was applied in the X-zone Class III oil reservoir test area, which has a total of 14 injection wells and 21 production wells. The test area began blank waterflooding in June 2019. Using the injection well adjustment chart, the injection wells were guided to increase their injection rate 7 times, fracture 4 times, decrease their injection rate 5 times, and control production with reduced injection rate 2 times. Using the production well adjustment chart, the production wells were guided to adjust their parameters to high or low levels 3 times, low or low levels 10 times, and fracture 4 times. Through comprehensive adjustments at both the injection and production ends, the average pressure increase space in the study area increased from 5.2 MPa before adjustment to 6.0 MPa before polymer injection, and the flowing pressure increased from 3.08 MPa before adjustment to 4.93 MPa. The pressure distribution on the plane became more balanced, laying a good pressure system foundation for the uniform advancement of the polymer front.

[0092] 1. For example Figure 1 As shown, the injection well adjustment chart is used to guide the comprehensive adjustment of injection wells:

[0093] ① Further explanation of the injection rate adjustment chart for injection well A, which is located in the acceleration zone, is provided.

[0094] Basic information about Well A1: Before adjustment, the pressure rise potential of this well was 7.5 MPa, and the injection-production ratio was 0.86. Based on the pressure rise potential and the injection-production ratio, the area where Well A1 is located was identified as the acceleration zone on the injection well adjustment chart. The injection rate of this well was promptly increased. Compared with before the adjustment, the pressure rise potential decreased from 7.5 MPa to 5.8 MPa, and the injection-production ratio increased from 0.86 to 1.01. Based on the pressure rise potential and injection-production ratio of Well A1 after the adjustment, the area on the chart was identified. The results show that Well A1 is now in a reasonable zone after the acceleration.

[0095] During the initial water drive phase, the injection rates of seven injection wells in the acceleration zone were increased according to the injection well adjustment chart. After the adjustment, the average single-well pressure increase potential decreased by 1.1 MPa, and the daily injection volume increased by 104 m³. 3 The injection-production ratio increased by 0.23. Based on the pressure increase potential of the single well after the adjustment and the injection-production ratio, the area shown in the chart was identified. The results show that all seven wells are now within the reasonable range. The statistical effects of the injection wells before and after the acceleration in the study area are shown in Table 1.

[0096] Table 1

[0097]

[0098] ② Further explanation of the injection rate adjustment chart for injection well B1, which is located in the deceleration zone, is provided.

[0099] Basic information about Well B1: Before adjustment, the pressure rise potential of this well was 3.9 MPa, and the injection-production ratio was 1.21. Based on the pressure rise potential and injection-production ratio, the area where Well B1 is located was identified as a rate-reducing zone on the injection well adjustment chart. The injection rate of this well was promptly reduced. Compared with before the adjustment, the pressure rise potential increased from 3.9 MPa to 5.5 MPa, and the injection-production ratio decreased from 1.21 to 0.95. Based on the pressure rise potential and injection-production ratio of Well B1 after the adjustment, the area on the chart was identified. The results show that Well B1 is now in a reasonable zone after the rate increase.

[0100] During the blank water drive phase, according to the injection well adjustment chart, the injection rate of the five injection wells in the deceleration zone was reduced. After the adjustment, the average single-well pressure increased by 1.1 MPa, and the daily injection volume decreased by 80 m³. 3 The injection-production ratio decreased by 0.31. Based on the pressure increase potential of the single well after the adjustment and the injection-production ratio, the area shown in the chart was identified. The results show that all five wells are now in the reasonable range. The statistical effects of the injection wells before and after the acceleration in the study area are shown in Table 2.

[0101] Table 2

[0102]

[0103] ③ Further explanation of the injection well adjustment chart for fracturing injection well C1, which is located in the fracturing zone.

[0104] Basic information about well C1: Before fracturing, the pressure rise potential of this well was 2.9 MPa, and the injection-production ratio was 0.34. Based on the pressure rise potential and the injection-production ratio, the area where well C1 is located was identified as the fracturing zone on the injection well adjustment chart. Fracturing was promptly carried out on this well. Compared with before fracturing, the pressure rise potential increased from 2.9 MPa to 5.8 MPa, and the injection-production ratio increased from 0.34 to 0.92. Based on the adjusted pressure rise potential and injection-production ratio of well C1, the area on the chart was identified. The results show that well C1 is now in a reasonable zone after the acceleration.

[0105] During the blank water drive phase, according to the injection well adjustment chart, fracturing was performed on four injection wells located in the fracturing zone. After fracturing, the average single-well pressure increased by 3.0 MPa, and the daily injection volume increased by 104 m³. 3 The injection-production ratio increased by 0.42. Based on the pressure increase potential of the single well after the adjustment and the injection-production ratio, the area shown on the chart was identified. The results show that all four wells are now within the reasonable range. The statistical effects of the injection wells before and after the acceleration in the study area are shown in Table 3.

[0106] Table 3

[0107]

[0108] ④ The injection rate of injection well D1, located in the rate-reduction and production control zone, will be lowered. Simultaneously, the production rate of the connected production well will also be lowered. Further explanation of the injection well adjustment chart is provided.

[0109] Basic information about well D1: Before adjustment, the pressure rise potential of this well was 6.2 MPa, and the injection-production ratio was 1.06. Based on the pressure rise potential and the injection-production ratio, the area where well D1 is located was identified as a rate-reduction and production control zone on the injection well adjustment chart. The injection rate of this well and the production rate of the connected production well were promptly reduced. Compared with before the adjustment, the pressure rise potential decreased from 6.2 MPa to 5.5 MPa, and the injection-production ratio decreased from 1.06 to 0.95. Based on the pressure rise potential and injection-production ratio of well D1 after the adjustment, the area on the chart was identified. The results show that well D1 is now in a reasonable zone after the adjustment.

[0110] During the blank water drive phase, according to the injection well adjustment chart, the injection rates of two injection wells located in the rate-reduction and production control zone were adjusted downwards, and the production rates of the connecting wells were also adjusted downwards. After the adjustment, the average single-well pressure increase potential decreased by 1.1 MPa, and the daily injection volume decreased by 40 m³. 3 The injection-production ratio was reduced by 0.12. Based on the pressure increase space of the single well after adjustment and the injection-production ratio, the area in the chart was found. The results show that both wells are in the reasonable zone. The statistical effect of the injection well speed reduction and production control in the study area before and after is shown in Table 4.

[0111] Table 4

[0112]

[0113] 2. For example Figure 2 As shown, the method for guiding the comprehensive adjustment of produced wells using the produced well adjustment chart includes:

[0114] ① The stroke rate of well E1, a production well located in the low-parameter adjustment zone, will be reduced. Further explanation of the production well adjustment chart will be provided.

[0115] Basic information about Well E1: This well produces 50 tons of fluid per day and has a flowing pressure of 1.86 MPa. Based on the well's daily fluid production and flowing pressure, the area where Well E1 is located was identified as a low-parameter adjustment zone on the production well adjustment chart. Therefore, the well's stroke rate was promptly reduced from 5 strokes / min to 4 strokes / min. Compared to before the adjustment, the daily fluid production decreased from 50 tons to 34 tons, the daily oil production decreased from 4.1 tons to 2.5 tons, the water cut increased from 91.80% to 92.70%, and the flowing pressure increased from 1.86 MPa to 4.56 MPa, an increase of 2.70 MPa.

[0116] During the initial waterflooding phase in the study area, 10 producing wells were located in the low-parameter zone. Timely adjustments to production parameters resulted in a decrease in daily fluid production from 359t to 174t, daily oil production from 22.8t to 10.4t, an increase in overall water cut from 93.65% to 94.00%, and an increase in flowing pressure from 1.70MPa to 4.33MPa. Based on the adjusted daily fluid production and flowing pressure of individual wells, the zones shown on the chart were identified. The results indicate that all 10 wells are now within the reasonable range. Statistics of low-parameter wells in the study area are shown in Table 5.

[0117] Table 5

[0118]

[0119] ② The stroke rate of well F1, a production well located in the high-efficiency zone, will be adjusted upwards. Further explanation of the adjustment chart for production wells will be provided.

[0120] Basic information about Well F1: This well produces 21 tons of fluid per day and has a flowing pressure of 7.00 MPa. Based on the well's daily fluid production and flowing pressure, the area where Well F1 is located was identified as an area for adjusting parameters on the production well adjustment chart. Therefore, the well's stroke rate was promptly adjusted upwards from 3 strokes / min to 4 strokes / min. Compared to before the adjustment, the daily fluid production increased from 21 tons to 28 tons, the daily oil production increased from 1.0 tons to 1.6 tons, the water cut decreased from 95.20% to 94.30%, and the flowing pressure decreased from 7.00 MPa to 4.90 MPa, a decrease of 2.16 MPa.

[0121] During the initial waterflooding phase in the study area, three producing wells were located in the region requiring increased production parameters. Timely adjustments to these parameters resulted in a significant increase in daily fluid production from 57t to 85t, daily oil production from 1.7t to 2.9t, a decrease in overall water cut from 97.10% to 96.57%, and a decrease in flowing pressure from 6.06MPa to 4.15MPa. Based on the adjusted daily fluid production and flowing pressure of each well, the regions shown on the chart were identified, indicating that all three wells were now within the reasonable range. Statistics on wells requiring reduced production parameters in the study area are shown in Table 6.

[0122] Table 6

[0123]

[0124] ③ Fracturing was performed on well G1, a production well located in the fracturing zone. Further explanation of the adjustment chart for the production well was provided.

[0125] Basic information about Well G1: This well produces 22 tons of fluid per day and has a flowing pressure of 1.46 MPa. Based on the well's daily fluid production and flowing pressure, the area where Well G1 is located was identified as a fracturing zone on the well production adjustment chart, and fracturing was promptly performed on the well. Compared with before fracturing, the daily fluid production increased from 22 tons to 39 tons, the daily oil production increased from 0.4 tons to 1.1 tons, the water cut decreased from 98.00% to 97.20%, and the flowing pressure increased from 1.46 MPa to 4.72 MPa, an increase of 3.26 MPa.

[0126] In the study area, during the initial waterflooding phase, four production wells were located in the fracturing zone. Timely fracturing of these four wells resulted in an increase in daily fluid production from 43t to 146t, daily oil production from 3.1t to 16.0t, a decrease in overall water cut from 92.82% to 89.06%, and an increase in flowing pressure from 1.52MPa to 4.89MPa compared to before fracturing. Based on the adjusted daily fluid production and flowing pressure of each well, the zones shown on the chart were determined, indicating that all four wells were now within the reasonable range. Statistics on fracturing wells in the study area are shown in Table 7.

[0127] Table 7

[0128]

[0129] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A method for establishing an adjustment chart for injection-production wells in a blank water drive stage of three types of oil reservoirs, characterized in that: This includes methods for establishing adjustment charts for injection wells and production wells; The method for establishing the injection well adjustment chart includes: A rectangular diagram is constructed with the injection-production ratio of the injection well as the length of the rectangle, ranging from 0 to 1.4; and the pressure space of the injection well as the width of the rectangle, ranging from 0 to 10, in MPa. The chart is divided into five areas: the rational zone, the acceleration zone, the fracturing zone, the deceleration zone, and the deceleration-controlled mining zone. The method for establishing the production well adjustment chart includes: A rectangular chart is constructed with the produced well flowing pressure as the length of a rectangle, ranging from 0 to 7.0 MPa; and the daily fluid production as the width of a rectangle, ranging from 0 to 50 tons. The chart contains four regions. The diagram is divided into four areas: fracturing zone, low parameter adjustment zone, reasonable parameter adjustment zone, and high parameter adjustment zone.

2. The method for establishing the injection-production well adjustment chart for the three types of oil reservoir blank water drive stage according to claim 1, characterized in that: For the established injection well adjustment chart: The rectangular area formed by the long side ranging from 0.9 to 1.1 and the wide side ranging from 4 MPa to 6 MPa is a reasonable area; The polygonal region formed by removing the reasonable area from the rectangular region with the long side ranging from 0 to 1.0 and the wide side ranging from 5 MPa to 10 MPa is the speed-up zone. The rectangular area with a long side ranging from 0 to 1.0 and a wide side ranging from 0 MPa to 5 MPa, after removing the reasonable area, forms a polygonal area, which is the fracturing zone. The rectangular region with a long side ranging from 1.0 to 1.4 and a wide side ranging from 0 MPa to 5 MPa, after removing the reasonable area, forms a polygonal region, which is the deceleration region. The rectangular area with a long side ranging from 1.0 to 1.4 and a wide side ranging from 5 MPa to 10 MPa, after removing the reasonable area, forms a polygonal area, which is the rate-reducing and controlled mining area.

3. The method for establishing the injection-production well adjustment chart for the three types of oil reservoir blank water drive stage according to claim 1, characterized in that: For the established production well adjustment chart: The rectangular area formed by the long side ranging from 0MPa to 2.0MPa and the wide side ranging from 0t to 25t is the fracturing zone; The rectangular region formed by the long side ranging from 0.0MPa to 2.0MPa and the wide side ranging from 25t to 50t is the parameter adjustment region; A rectangular area with a long side ranging from 2.0MPa to 5.0MPa and a wide side ranging from 0t to 50t is considered a reasonable range. The rectangular region formed by the long side ranging from 5.0MPa to 7.0MPa and the wide side ranging from 0t to 50t is the parameter adjustment region.

4. A method for using an adjustment chart for injection-production wells in the blank water drive stage of three types of oil reservoirs, established according to any one of claims 1 to 3, characterized in that: Based on the constructed injection well adjustment chart and production well adjustment chart, relevant areas are selected and corresponding adjustment methods are applied according to the relevant adjustment parameters.

5. The method for using the injection-production well adjustment chart for the blank water drive stage of three types of oil reservoirs according to claim 4, characterized in that: Based on the constructed injection well adjustment map, and according to the injection-production ratio and pressure space of the injection well, relevant areas are selected for corresponding adjustment methods, including the following steps: Wells with an injection-production ratio ranging from 0.9 to 1.1 and a pressure range of 4 MPa to 6 MPa are within a reasonable zone of the rectangular area; the current injection parameters should be maintained for wells within the reasonable zone. The injection wells with an injection-production ratio ranging from 0 to 1.0 and a pressure range of 5 MPa to 10 MPa are located in the acceleration zone of the polygonal region formed after removing the reasonable area from the rectangular region; the injection wells located in the acceleration zone are accelerated. The injection-production ratio of the injection well is in the range of 0-1.0, and the pressure space is in the range of 0MPa-5MPa. The well is located in the fracturing zone of the polygonal area formed after removing the reasonable area from the rectangular area; the injection well located in the fracturing zone is subjected to fracturing. For injection wells with an injection-production ratio ranging from 1.0 to 1.4 and a pressure range of 0 MPa to 5 MPa, the injection rate of the well is reduced within the polygonal region formed after removing the reasonable zone from the rectangular region. The injection rate of the injection wells located within the reduced-rate zone is then lowered. The injection-production ratio of the injection well is in the range of 1.0-1.4, and the pressure range is in the range of 5MPa-10MPa. The injection well is located in the polygonal area formed after removing the reasonable area from the rectangular area. The injection rate of the injection well in the reduced-rate production zone is adjusted down, and the production rate of the production well is controlled.

6. The method for using the injection-production well adjustment chart for the blank water drive stage of three types of oil reservoirs according to claim 5, characterized in that: To accelerate the injection wells located within the acceleration zone, the specific method is as follows: for injection wells with an injection-production ratio ≤ 0.9 and an injection pressure space ≥ 7 MPa, the daily injection volume is increased by 20 m³ / s. 3 When the injection pressure space is ≥7MPa, for injection wells with an injection-production ratio greater than 0.9, the daily injection volume can be increased by 15m³. 3 When the injection pressure space is ≥6MPa and <7MPa, the daily injection volume is increased by 15m. 3 When the injection pressure space is <6MPa, the daily injection volume is increased by 12m. 3 ; For injection wells located within the fracturing zone, fracturing is performed using the following methods: for oil layers with a perforation thickness ≥ 1.5m, multi-fracture fracturing is used; for oil layers with a perforation thickness less than 1.5m, conventional fracturing is used. The injection rate of injection wells located in the aforementioned deceleration zone is reduced. Specifically, when the injection pressure space is ≥4MPa and <5MPa, the daily injection volume is reduced by 20m³. 3 When the injection pressure space is ≥3MPa and <4MPa, the daily injection volume should be reduced by 15m. 3 When the injection pressure space is <3MPa, the daily injection volume should be reduced by 10m³. 3 ; While reducing the injection rate of injection wells located within the reduced-rate production control zone, the production rate of production wells is also controlled. Specifically, when the injection pressure space is ≥8MPa, the daily injection volume is reduced by 25m³. 3 The daily injection volume is reduced by 20m when the injection pressure space is ≥6MPa and <8MPa. The production well is connected to a control fluid volume of 50t. 3 The daily injection volume is reduced by 10m when the injection pressure space is <6MPa. (Note: The original text also mentions a production well with a control fluid volume of 40t, but this seems unrelated to the injection volume and is likely a separate, incomplete sentence.) 3 , connected to the production well to control fluid 30t.

7. The method for using the injection-production well adjustment chart for the blank water drive stage of three types of oil reservoirs according to claim 4, characterized in that: Based on the constructed production well adjustment chart, and according to the two parameters of production well flowing pressure and daily fluid production of the well, relevant areas are selected for corresponding adjustment methods, including the following steps: Wells with a production pressure range of 0MPa-2.0MPa and a daily fluid production range of 0t-25t are located in a rectangular fracturing zone. Fracturing is performed on the production wells located in the fracturing zone. Wells with a production pressure range of 0.0MPa-2.0MPa and a daily fluid production range of 25t-50t are located in the rectangular parameter reduction zone. The production parameters of the production wells located in the parameter reduction zone are adjusted to be smaller. Wells with a production pressure range of 2.0MPa-5.0MPa and a daily fluid production range of 0t-50t are located in a reasonable zone within the rectangular area. Production parameters for production wells within this reasonable zone are maintained. Wells with a production pressure range of 5.0MPa-7.0MPa and a daily fluid production range of 0t-50t are located in the parameter adjustment zone of the rectangular area. The production parameters of the wells located in the parameter adjustment zone are adjusted to be increased.

8. The method for using the injection-production well adjustment chart for the blank water drive stage of three types of oil reservoirs according to claim 7, characterized in that: The production wells located in the fracturing zone are subjected to fracturing. Specifically, for oil layers with a perforation thickness ≥ 1.5m, multi-fracture fracturing is used, and for oil layers with a perforation thickness less than 1.5m, conventional fracturing is used. The production parameters of the wells in the reduced parameter zone are adjusted by reducing the following method: for wells with room for reduction in stroke rate, the stroke rate is reduced first; for wells without room for reduction in stroke rate, the stroke is reduced; when none of the above parameters can be met, the well is replaced with a smaller pump. The production parameters of the wells in the above-mentioned parameter adjustment zone are increased. The specific method is as follows: for wells with room for increasing stroke rate, the stroke rate is increased first. For wells without room for increasing stroke rate, the stroke length is increased. When the above parameters cannot be met, the well is replaced with a larger pump.

9. The method for using the injection-production well adjustment chart for the blank water drive stage of three types of oil reservoirs according to claim 7, characterized in that: The production parameters of the wells produced in the adjusted low-parameter zone include stroke, number of strokes, and pump diameter. The production parameters of the wells produced in the large-scale production area include stroke, number of strokes, and pump diameter.

10. An adjustment chart for injection-production wells in the blank water drive stage of three types of oil reservoirs, established by the method according to any one of claims 1 to 3, can be directly applied to the blank water drive stage of three types of oil reservoirs.

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