Profile control and displacement process selection method for controlling bottom water invasion of Jurassic oil reservoir

Abstract

The invention discloses a profile control and displacement process selection method for controlling bottom water invasion of a Jurassic oil reservoir. The method comprises the following steps: firstly, collecting data of accumulative oil production, accumulative water production, accumulative injection rate, geological reserves, a crude oil volume coefficient, a formation water volume coefficient, a comprehensive compression coefficient, a crude oil original volume coefficient, formation original pressure and current oil reservoir pressure of an oil reservoir, then calculating the water invasion amount of a block over the years by utilizing the collected data, and drawing a curve; s2, selecting a profile control and displacement process according to the water invasion value and the water invasion curve trend of the block over the years; and S3, carrying out profile control and displacement on the well group, needing profile control and displacement, of the Jurassic bottom water reservoir according to the profile control and displacement process selected in the step S2. According to the method, the water invasion condition of the bottom water of the Jurassic oil reservoir is calculated and represented, different states of the water invasion of the bottom water oil reservoir are calculated, and different profile control and displacement processes are screened according to the different states of the water invasion of the bottom water oil reservoir, so that the purposes of controlling the water invasion of the bottom water and inhibiting the water content are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir. Background Art

[0002] At present, most of my country's oil fields have entered the medium-high water content period. After entering the high water content period, the oil production rate decreases rapidly. Among these high water-content oil fields, bottom water reservoirs account for a huge number and have rich reserves. In oil reservoirs with bottom water, before the oil reservoir is exploited, the water is located in the lower part of the oil layer, and the upper oil layer will form a hemispherical potential distribution when the layer is opened. Due to the influence of the vertical potential gradient, the oil-water contact surface will be deformed, and the potential gradient will reach the maximum along the well axis, forming a water cone. As the oil and gas production rate increases, the water cone continues to rise and breaks through into the bottom of the well, causing oil and water or gas and water to be produced at the same time, reducing the oil and gas production. This process of bottom water advancing longitudinally in a cone shape with oil and gas production is called bottom water cone advance. Once the bottom water cone advances, it is very unfavorable to the exploitation of oil and gas reservoirs. Because the bottom water enters the wellbore, it will cause a large amount of water production in the oil and gas wells, resulting in a significant reduction in oil and gas production, or even oil and gas production suspension, which seriously affects the normal production and benefits of the oil and gas wells.

[0003] To control the water intrusion of bottom water reservoirs, the current method is mainly to inject polymers, oil-water emulsions, foam or air into the water injection wells to increase the viscosity of the water phase to delay the water cone. Search for the flooding process selection of bottom water reservoirs and find relevant technologies. The following three are examples:

[0004] The invention patent with the patent publication (announcement) number CN 116066039A discloses a method for late-stage oil recovery in high-water-content sandstone reservoirs with strong bottom water. The method adopts a dual-horizontal well injection mixed gas mode. The dual-horizontal well includes a horizontal injection well and a horizontal oil production well. The mixed gas includes carbon dioxide and nitrogen. For oil reservoirs where low water drive efficiency is the main contradiction and water cone is a secondary contradiction, the bottom horizontal well is used to inject mixed gas and the top horizontal well is used to produce oil; for oil reservoirs where water cone is the main problem and low water drive efficiency is a secondary contradiction, the top horizontal well is used to inject mixed gas and the bottom horizontal well is used to produce oil. After effectively controlling the water cone, the oil recovery effect is further exerted. First, for water cone oil reservoirs, this method ignores the size and degree of water cone. Secondly, it is necessary to replace the injection string suitable for CO2, and the wellbore operation is relatively cumbersome.

[0005] The invention patent with patent publication (announcement) number CN104342095B discloses a self-gassing expandable foam jelly and its preparation method and application. Although the self-gassing expandable foam jelly can solve the problem of edge and bottom water intrusion, it does not involve the subsequent flooding process selection.

[0006] The invention patent with the patent publication (announcement) number CN112943162B discloses a method for rapidly densifying an artificial partition at the gas-water interface of an edge-bottom water gas reservoir, comprising: (1) injecting an aqueous monomer solution with a pH value between 10 and 12 into the gas-water interface, wherein the aqueous monomer solution is composed of an aqueous monomer and an aqueous solvent, and the mass fraction of the aqueous monomer is 2 to 5%; (2) injecting an oil-phase monomer solution into the gas-water interface, so that the oil-phase monomer solution spreads, and the gas-water interface is transformed into an oil-water interface, and the oil-phase monomer solution is injected into the gas-water interface. The liquid is composed of a new oil phase monomer, a spreading agent, nanoparticles and an oil phase solvent, the mass fraction of the new oil phase monomer is 0.1-1%, the mass fraction of the spreading agent is 0.05-0.1%, and the amount of nanoparticles added is 0.01-0.02 g / ml; (3) the water phase monomer in the water layer undergoes an interfacial polymerization reaction with the new oil phase monomer to form a polymer water barrier layer at the oil-water interface; (4) under the production pressure difference, the impurity particles block the pore throat, crystallization occurs, and a denser polymer water barrier layer is formed. This method does not involve the judgment of the water intrusion amount of the water body. Summary of the invention

[0007] The present invention aims to provide a method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir, so as to overcome the above technical defects.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir comprises the following steps:

[0010] S1, first collect the cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and current reservoir pressure data of the oil reservoir, and then use the collected data to calculate the water invasion volume of the block over the years and draw a curve;

[0011] S2, select the flooding technology according to the water influx values ​​and water influx curve trends of the block over the years;

[0012] S3, performing flooding on the well group that needs flooding in the Jurassic bottom water reservoir according to the flooding technology selected in step S2.

[0013] Furthermore, the water intrusion calculation formula for the block over the years is:

[0014] We=N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o

[0015] Where:

[0016] W e The amount of water intrusion;

[0017] N p is the cumulative oil production, in units of 10 4 t;

[0018] B o is the crude oil volume coefficient;

[0019] ρ o is the density of crude oil, in t / m 3 ;

[0020] W p is the cumulative water production, the unit is 10 4 m 3 ;

[0021] B w is the formation water volume coefficient;

[0022] W i is the cumulative injection volume, the unit is 10 4 m 3 ;

[0023] C t is the comprehensive compression factor;

[0024] N is geological reserves, unit is 10 4 t;

[0025] B oi is the original volume coefficient of crude oil;

[0026] ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

[0027] Furthermore, the cumulative oil production N p It is obtained by adding up the monthly oil production of each oil well in the reservoir since the start of production.

[0028] Furthermore, the cumulative water production W p It is obtained by adding up the monthly water production of each oil well in the reservoir since the start of production.

[0029] Furthermore, the cumulative water injection volume W i It is obtained by adding up the monthly water injection volume of each injection well since the start of production.

[0030] Furthermore, the specific method for selecting the flooding process according to the water influx values ​​and water influx curve trends of the block over the years is:

[0031] (1) When the bottom water intrusion is negative, it indicates that the bottom water is suppressed and polymer microspheres are selected for flooding;

[0032] (2) When the bottom water invasion is positive and the invasion trend is decreasing year by year, it indicates that the bottom water has invaded the reservoir but has been suppressed. PEG series gel particles are selected for flooding, and the production intensity is reduced to continuously slow down the bottom water uplift;

[0033] (3) When the bottom water invasion is positive and the invasion trend increases year by year, it indicates that the bottom water has invaded the reservoir and the invasion is increasing year by year. Viscoelastic self-regulating agents are selected for flooding to suppress the invasion of bottom water.

[0034] Preferably, the injection volume concentration of the polymer microspheres is 0.1%-0.15%, and the injection amount is 8-10t.

[0035] Preferably, the particle size of the polymer microspheres is 50-100 nm.

[0036] Preferably, the injection volume concentration of the PEG series gel particles is 0.4-06%, and the injection amount is 8-10t.

[0037] Preferably, the injection volume concentration of the viscoelastic self-regulating agent is 0.1-0.15%.

[0038] Preferably, the injection amount of the viscoelastic self-regulating agent is 5-6t.

[0039] Preferably, the liquid extraction intensity is achieved by reducing the stroke frequency.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention calculates and characterizes the bottom water invasion conditions of Jurassic oil reservoirs, calculates different states of bottom water invasion in oil reservoirs, and screens different flooding processes according to the different states of bottom water invasion in oil reservoirs, in order to achieve the purpose of controlling bottom water invasion and suppressing water content.

[0042] 2. The method for selecting a flooding process for controlling bottom water invasion in a Jurassic oil reservoir provided by the present invention specifically comprises the following steps: calculating the amount of water invasion over the years according to a material balance equation, judging the state of bottom water invasion according to the value and change trend of the water invasion, and selecting a flooding process according to the state of bottom water invasion: when the bottom water invasion is a negative value, it indicates that the bottom water is suppressed in the block, and polymer microspheres are selected for flooding to effectively improve the water flooding contradiction; when the bottom water invasion is a positive value and the trend is decreasing year by year, it indicates that the bottom water has invaded the oil reservoir and has been suppressed year by year, and PEG series gel particles are selected, and the production intensity is reduced at the same time to continuously slow down the bottom water rise; when the bottom water invasion is a positive value and the trend is increasing year by year, it indicates that the bottom water has invaded the oil reservoir and the invasion is increasing year by year, and a viscoelastic self-regulating agent is selected to increase the viscosity of the dominant channel and suppress the invasion of bottom water.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other design solutions and drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 It is the comprehensive production curve of Yan 9 oil reservoir;

[0046] Figure 2 This is the graph showing the change of reservoir water intrusion with development time in the A62 area of ​​the Yan9 oil reservoir;

[0047] Figure 3 This is the dynamic curve diagram of the PEG flooding well group in the A62 Yan9 reservoir;

[0048] Figure 4 This is the comprehensive production curve of Z8 Yan9 reservoir;

[0049] Figure 5 This is the change chart of natural decline, comprehensive decline and water content increase rate of Z8 Yan9 reservoir over the years;

[0050] Figure 6 This is the graph showing the change of water intrusion in the Z8 area reservoir with development time;

[0051] Figure 7 This is a diagram showing the changes in water drive control degree, water drive efficiency, and pressure maintenance level of the Z8 oil reservoir over the years.

[0052] Figure 8 This is the comprehensive development curve of the oil reservoir in Z8 area;

[0053] Fig. 9 This is the comprehensive production curve of Yan 10 oil reservoir;

[0054] Fig.10 This is the bottom water contact relationship diagram of the X4 area;

[0055] Fig.11 This is the graph showing the change of water intrusion in the X4 area reservoir with development time;

[0056] Fig.12 This is the dynamic curve of the viscoelastic self-regulating agent well group 4 in the northeast of the reservoir.

[0057] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0058] The content of the present invention can be further understood by combining the following detailed description of the preferred implementation method of the present invention and the embodiments included. Unless otherwise stated, all technical and scientific terms used in this article have the same meaning as those of ordinary skill in the art to which the present invention belongs. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in the present invention, the definition of the term provided in the present invention shall prevail.

[0059] The present invention provides a method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir, comprising the following steps:

[0060] S1, first collect the cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and current reservoir pressure data of the oil reservoir, and then use the collected data to calculate the water invasion volume of the block over the years and draw a curve;

[0061] S2, select the flooding technology according to the water influx values ​​and water influx curve trends of the block over the years;

[0062] S3, performing flooding on the well group that needs flooding in the Jurassic bottom water reservoir according to the flooding technology selected in step S2.

[0063] Furthermore, the water intrusion calculation formula for the block over the years is:

[0064] W e =N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o

[0065] Where:

[0066] W e The amount of water intrusion;

[0067] N p is the cumulative oil production, in units of 10 4 t;

[0068] B o is the crude oil volume coefficient;

[0069] ρ ois the density of crude oil, in t / m 3 ;

[0070] W p is the cumulative water production, the unit is 10 4 m 3 ;

[0071] B w is the formation water volume coefficient;

[0072] W i is the cumulative injection volume, the unit is 10 4 m 3 ;

[0073] C t is the comprehensive compression factor;

[0074] N is geological reserves, unit is 10 4 t;

[0075] B oi is the original volume coefficient of crude oil;

[0076] ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

[0077] Furthermore, the cumulative oil production N p It is obtained by adding up the monthly oil production of each oil well in the reservoir since the start of production.

[0078] Furthermore, the cumulative water production W p It is obtained by adding up the monthly water production of each oil well in the reservoir since the start of production.

[0079] Furthermore, the cumulative water injection volume W i It is obtained by adding up the monthly water injection volume of each injection well since the start of production.

[0080] Furthermore, the specific method for selecting the flooding process according to the water influx values ​​and water influx curve trends of the block over the years is:

[0081] (1) When the bottom water invasion is negative, it indicates that the bottom water is suppressed in the area, and polymer microspheres are selected for flooding to effectively improve the water flooding contradiction; the polymer microspheres can preferably be nano-scale polymer microspheres for flooding or polyacrylamide polymer microspheres WQ50N produced by Xi'an Wande Energy Chemical Co., Ltd., with a production batch number of 202308130005;

[0082] (2) When the bottom water invasion is positive and the invasion trend is decreasing year by year, it indicates that the bottom water has invaded the reservoir but has been suppressed. PEG series gel (i.e., polymer elastic gel) particles are selected for displacement, and the fluid production intensity is reduced (preferably by reducing the stroke frequency) to continuously slow down the bottom water uplift; among them, the PEG series gel particles can preferably be the polyacrylamide displacement agent PEG-1 for enhanced oil recovery produced by Gansu Zhongke Polymer Petroleum Technology Co., Ltd., with a production batch number of 202303154004;

[0083] (3) When the bottom water invasion is positive and the invasion trend increases year by year, it indicates that the bottom water has invaded the oil reservoir and the invasion is increasing year by year. A viscoelastic self-regulating agent is selected for displacement to increase the viscosity of the dominant channel and inhibit the invasion of bottom water. The viscoelastic self-regulating agent can preferably be a silicate oil displacement agent NT-1 for oil production produced by Shaanxi Rixin Petrochemical Co., Ltd., with a production batch number of 202305201008.

[0084] Preferably, the injected volume concentration of the polymer microspheres is 0.1%-0.15%, and the injected amount is 8-10t.

[0085] Preferably, the particle size of the polymer microspheres is 50-100 nm.

[0086] Preferably, the injection volume concentration of the PEG series gel particles is 0.4-06%, and the injection amount is 8-10t.

[0087] Preferably, the injection volume concentration of the viscoelastic self-regulating agent is 0.1-0.15%, and the injection amount is 5-6t.

[0088] The present invention will be further described below in conjunction with embodiments:

[0089] Example 1

[0090] A6 Yan9 Reservoir: Reference Figure 1 The oil reservoir was established and put into production in 2009. The development layer is Yan 9, with an average oil layer thickness of 9.9m, a porosity of 17.6%, a permeability of 24.2mD, an oil saturation of 51.5%, and an original formation pressure of 10.8MPa.

[0091] The reservoir has weakly developed edge and bottom water. After long-term water injection, the profile contradictions are prominent, there are water drive dominant channels, and the water content continues to rise rapidly.

[0092] The cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and historical and current reservoir pressure data of the reservoir are shown in Table 1.

[0093] Using the data in Table 1, the water intrusion over the years is calculated based on the material balance equation. The calculation formula is:

[0094] We=N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o

[0095] Where:

[0096] W e is the water intrusion; N p is the cumulative oil production, in units of 10 4 t; B o is the crude oil volume coefficient; ρ o is the density of crude oil, in t / m 3 ; W p is the cumulative water production, the unit is 10 4 m 3 ; B w is the formation water volume coefficient; W i is the cumulative injection volume, the unit is 10 4 m 3 ; C t is the comprehensive compression coefficient; N is the geological reserves, the unit is 10 4 t; B oi is the original volume coefficient of crude oil; ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

[0097] Table 1

[0098]

[0099] Based on the calculated water invasion value, draw a curve of water invasion versus formation pressure, such as Figure 2 shown.

[0100] Depend on Figure 2 It can be seen that the bottom water in this block is relatively developed. In recent years, due to the high intensity of liquid production, the bottom water has invaded the reservoir but has been suppressed year by year. The current formation pressure is 9.8MPa, and the water invasion volume reaches 7.37×10 4 m 3 .

[0101] Combined with the bottom water invasion, PEG flooding was implemented in March 2021 (the bottom water invasion in the figure is positive and the trend is decreasing year by year, indicating that the invasion is under control year by year, and PEG series gel particles are selected for flooding). The single well dosage is 8t, refer to Figure 3After implementation, the monthly reduction was 3.5%↓-0.9%, the monthly water cut increased by 0.7%↓-0.4%, and the crude oil reduction was reduced by 3,401 tons in stages, with significant adjustment and displacement effects.

[0102] Example 2

[0103] Z8 Yan9 reservoir, reference Figure 4 The reservoir was established in 1997, with the development layer being Yan 9, with an average oil layer thickness of 13.3 m, an average effective porosity of 19.6%, an air permeability of 33.2 × 10-3 μm2, a permeability of 24.2 mD, and an original formation pressure of 7.65 MPa.

[0104] Depend on Figure 5 It can be seen that the bottom water of the reservoir is developed in the central and western parts. Due to the dual influence of bottom water and injected water, the comprehensive water content continues to rise (88.1%), the recovery degree of recoverable reserves is high (81.0%), and the water storage rate decreases.

[0105] The cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and historical and current reservoir pressure data of the reservoir are shown in Table 2.

[0106] Using the data in Table 2, the water intrusion over the years was calculated based on the material balance equation. The calculation formula is:

[0107] We=N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o

[0108] Where:

[0109] W e is the water intrusion; N p is the cumulative oil production, in units of 10 4 t; B o is the crude oil volume coefficient; ρ o is the density of crude oil, in t / m 3 ; W p is the cumulative water production, the unit is 10 4 m 3 ; B w is the formation water volume coefficient; W i is the cumulative injection volume, the unit is 10 4 m 3 ; C tis the comprehensive compression coefficient; N is the geological reserves, the unit is 10 4 t; B oi is the original volume coefficient of crude oil; ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

[0110] Table 2

[0111]

[0112] According to the value of water invasion, draw the curve of water invasion changing with formation pressure, such as Figure 6 shown.

[0113] The variation of water invasion volume in Z8 reservoir with development time is shown in Figure 7. The reservoir has been developed for 25 years. In the early stage, with the progress of development, the liquid production intensity was high, the formation pressure decreased year by year, and the water invasion volume increased year by year, reaching a maximum of 91.7×10 4 m 3 Since then, due to the strengthening of water injection and suppression of bottom water, the water invasion has been reduced year by year. At present, the formation pressure is 9.2MPa, the formation pressure remains at 112%, the water invasion is negative, and the injected water occupies a dominant position in the production layer.

[0114] Schematic diagram of water drive degree ( Figure 8 ) It can also be seen that due to the enhanced water injection in the past four years, the overall reservoir pressure has remained at a high level.

[0115] In view of the bottom water intrusion, 100nm microsphere flooding with a concentration of 0.1% was implemented in 2017. Through comprehensive management such as microsphere flooding, injection and production control, the development situation has stabilized, with a natural decline of 3.6% and a water content increase rate of 0.6%.

[0116] Example 3

[0117] X4 Yan 10 reservoir, reference Fig. 9 , which was put into production in 2010. The development layer is Yan 10, with an average oil layer thickness of 9.1m, a porosity of 16.1%, an air permeability of 16.2mD, and an oil saturation of 48.9%. It is a low permeability oil reservoir.

[0118] like Fig.10 As shown, bottom water is developed in the whole area, with Class I and Class II bottom water contact wells accounting for 60.2%, and interlayers are only developed locally.

[0119] The cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and historical and current reservoir pressure data of the reservoir are shown in Table 3.

[0120] Table 3

[0121]

[0122] Using the data in Table 3, the water intrusion over the years was calculated based on the material balance equation. The calculation formula is:

[0123] We=N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o

[0124] Where:

[0125] W e is the water intrusion; N p is the cumulative oil production, in units of 10 4 t; B o is the crude oil volume coefficient; ρ o is the density of crude oil, in t / m 3 ; W p is the cumulative water production, the unit is 10 4 m 3 ; B w is the formation water volume coefficient; W i is the cumulative injection volume, the unit is 10 4 m 3 ; C t is the comprehensive compression coefficient; N is the geological reserves, the unit is 10 4 t; B oi is the original volume coefficient of crude oil; ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

[0126] The curve of reservoir water invasion changing with formation pressure is shown in Fig.11 As shown in the figure. The bottom water in this block is relatively developed. In recent years, due to the high intensity of liquid production, the water invasion is positive and has shown an increasing trend year by year, making it difficult to control water and stabilize oil. The current formation pressure is 9.8MPa, and the water invasion has reached 30.73×10 4 m 3 .

[0127] Combined with the bottom water intrusion situation, 10 viscoelastic self-regulating agents will be tested from April 2021, referring to Fig.12 The daily construction capacity of the 4 well groups in the northeast has increased from 16m 3 ↑26m 3 After the test, the daily oil production was 18.5t↑20.7t, and the comprehensive water content was 81.6%↓78.7%.

Claims

1. A method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir, characterized in that: The following steps are involved: S1, first collect the cumulative oil production, cumulative water production, cumulative injection volume, geological reserves, crude oil volume coefficient, formation water volume coefficient, comprehensive compression coefficient, crude oil original volume coefficient, formation original pressure and current reservoir pressure data of the oil reservoir, and then use the collected data to calculate the water invasion volume of the block over the years and draw a curve; S2, select the flooding technology according to the water influx values ​​and water influx curve trends of the block over the years; S3, performing flooding on the well group that needs flooding in the Jurassic bottom water reservoir according to the flooding technology selected in step S2.

2. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 1, characterized in that: In step S1, the water intrusion calculation formula of the block over the years is: We=N p B o / ρ o +W p B w -W i -C t B oi NΔP / ρ o Where: W e The amount of water intrusion; N p is the cumulative oil production, in units of 10 4 t; B o is the crude oil volume coefficient; ρ o is the density of crude oil, in t / m 3 ; W p is the cumulative water production, the unit is 10 4 m 3 ; B w is the formation water volume coefficient; W i is the cumulative injection volume, the unit is 10 4 m 3 ; C t is the comprehensive compression factor; N is geological reserves, unit is 10 4 t; B oi is the original volume coefficient of crude oil; ΔP is the difference between the original formation pressure and the current reservoir pressure, MPa.

3. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 2, characterized in that: The cumulative oil production N p It is obtained by adding up the monthly oil production of each oil well in the reservoir since the start of production; The cumulative water production W p It is obtained by adding up the monthly water production of each oil well in the reservoir since the start of production; The cumulative water injection volume W i It is obtained by adding up the monthly water injection volume of each injection well since the start of production.

4. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 1, characterized in that: According to the water influx values ​​and water influx curve trends of the block over the years, the specific method for selecting the flooding process is: (1) When the bottom water intrusion is negative, it indicates that the bottom water is suppressed and polymer microspheres are selected for flooding; (2) When the bottom water invasion is positive and the invasion trend is decreasing year by year, it indicates that the bottom water has invaded the reservoir but has been suppressed. PEG series gel particles are selected for flooding, and the production intensity is reduced to continuously slow down the bottom water uplift; (3) When the bottom water invasion is positive and the invasion trend increases year by year, it indicates that the bottom water has invaded the reservoir and the invasion is increasing year by year. Viscoelastic self-regulating agents are selected for flooding to suppress the invasion of bottom water.

5. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The injection volume concentration of the polymer microspheres is 0.1%-0.15%, and the injection amount is 8-10t.

6. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The particle size of the polymer microspheres is 50-100 nm.

7. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The injection volume concentration of the PEG series gel particles is 0.4-06%, and the injection amount is 8-10t.

8. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The injection volume concentration of the viscoelastic self-regulating agent is 0.1-0.15%.

9. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The injection amount of the viscoelastic self-regulating agent is 5-6t.

10. The method for selecting a flooding process for controlling bottom water intrusion in a Jurassic oil reservoir according to claim 4, characterized in that: The liquid extraction intensity is achieved by reducing the stroke frequency.

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