Method for preventing and consolidating sand through in-layer potential tapping

Abstract

The invention relates to a method for potential tapping, sand prevention and sand consolidation in a thick oil layer, which comprises the following steps of: S1, determining a measure target layer, and probing the layer number condition, the oil layer physical property, the fluid property, the energy condition, the production process and rule and the water content rising characteristic of the measure target layer; an effective injection channel is established, and favorable conditions of selective injection are created; s2, displacement pretreatment is conducted on the thick oil layer, the thick oil layer is squeezed and injected with a pretreatment agent for pretreatment, the main agent of the pretreatment agent is mahogany petroleum sulfonate, and 1-2.55% of polymer, salt and alkali are compounded according to the formation condition to form a multi-component composite oil displacement system; s3, deep plugging control, sand prevention and sand consolidation are conducted, and a thick oil layer of a third-system stratum is preferentially selected; s4, an artificial well wall is reconstructed; S5, perforation is repeated; repeatedly perforating the top boundary of the oil layer to weaken a water cone and realize sand prevention, water reduction and oil increase; the overall development level of an oil field is effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of conventional well repairing operation technology and supporting technology, and in particular relates to a method for tapping potential within a layer to prevent sand and consolidate sand. Background Art

[0002] With the late development of oil fields, most oil wells enter the high water content stage, and the development mode shifts from interlayer to intralayer, especially to thick oil layers. Water plugging in a single thick oil layer has some obvious effects, but a small number of sand production in the formation causes sand burial in the oil layer and pump jam, which reduces the effectiveness of the measures and seriously affects the normal production of the oil wells.

[0003] The article "Research and Application of Integrated Technology for Sand Control and Water Blockage in Gudong Oilfield" published by Zhang Guorong et al. in the February 2001 issue of "Petroleum Drilling and Production Technology" pointed out that in the middle and late stages of the development of loose sandstone reservoirs, the workload and difficulty of sand control and water blocking in oil fields continue to increase due to the dual contradictions of sand and water production in the oil layers. In response to this situation, a new integrated technology for sand control and water blocking was proposed, and the formulas of two sand control and water blocking agents, FD-1 and FD-2, were determined. Their performance was evaluated indoors, the type and dosage of pore expanding agents were determined, the effects of various formation factors on the performance of sand control and water blocking agents were investigated, the method and sequence of on-site construction and the formula for calculating the dosage of sand control and water blocking agents were determined, and the on-site application was analyzed.

[0004] The invention patent "Oil Well Sand Prevention and Selective Water Plugging Process" by Sun Jie et al., which was published on August 28, 2002, sintered a layer of hydrophobic material on the surface of quartz sand, and then mixed it with a hydratable carrier glue to make a viscous sand paste. Finally, the sand paste was squeezed into the oil layer through a fracturing truck, and a pre-coated sand well wall was formed between the oil layers around the well wall. After the carrier glue was hydrated, the sand particles formed an oil filter well wall with hydrophobic and oleophilic micropores. The sand and water mixed in the oil layer cannot enter the wellbore, while the crude oil can be easily lifted to the ground through the oil filter sand well wall. It has the characteristics of simple process and long service life, can save a lot of underground oil reservoir resources, and effectively improve the overall development level of the oil field.

[0005] Although the integrated sand control and water plugging technology has played a good role in sand control and oil production increase in sandstone reservoirs, there has been no relevant report on how to control water, stabilize oil and prevent sand in thick oil layers. Summary of the invention

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A method for tapping potential in thick oil layers to prevent sand and consolidate sand, comprising the following steps:

[0008] S1. Determine the target layer of the measure, explore the number of layers, oil layer physical properties, fluid properties, energy status, production history and laws, and water content rise characteristics of the target layer of the measure; establish an effective injection channel and create favorable conditions for selective injection;

[0009] S2. Pre-treatment of thick oil layers

[0010] Pretreatment of thick oil layers by squeezing pretreatment agents. The main agent of the pretreatment agent is petroleum sulfonate. According to the formation conditions (such as formation pH, mineralization, etc.), 1-2.55% of polymer, salt, and alkali are compounded to form a multi-component composite oil displacement system;

[0011] S3, deep plugging and sand control, giving priority to thick oil layers in the Tertiary strata;

[0012] S4. Reconstruction of artificial well wall

[0013] S5. Repeated perforation

[0014] Repeated perforation at the top of the oil layer can reduce the water cone, thereby preventing sand from falling and increasing oil production.

[0015] Furthermore, the effective thickness of the thick oil layer is ≥ 1.5 meters.

[0016] Furthermore, after the thick oil layer is pre-treated by displacement in step S2, the oil film between the sand particles can be peeled off, which is beneficial to the sand control and water blocking of the curing agent. The electrolyte in the pre-treatment agent can make the free high-valent particles in the plugging agent form a microcrystalline reinforcement structure, thereby improving the strength of the plugging agent.

[0017] Furthermore, after the deep plugging and sand control in step S3, water blocking increases the resistance of the dominant channel in the far well area, cements and solidifies the dominant channel in the near well area to reduce water production, makes the movable sand particles immobile, blocks the area near the well wall, weakens the channeling in the layer, increases the water avoidance height, makes the formation near the well wall resistant to scour and reduces sand production, and after the overall resistance of the dominant channel is increased, the oil displacement agent entering the deep formation can be effectively driven along the successive channels and parts to improve the recovery efficiency.

[0018] Furthermore, when conducting deep plugging and sand control, suspended and highly selective plugging agents and sand control agents are used to enter the middle and lower parts of thick oil layers, the direction of water advance and large pores that are preferentially flooded under the control and guidance of the pressure field to achieve deep and selective plugging, thereby achieving the effect of plugging waterways and consolidating formations.

[0019] Furthermore, when rebuilding the artificial well wall, the production pressure difference between the well wall and the area near the wellbore is large, and high-strength plugging agents are used to effectively block the water cone channel and the channel channel to rebuild the well wall structure.

[0020] Furthermore, when repeating the perforation in step S5, it is necessary to select layers and locations for repeated perforation with variable intensity according to formation conditions, production profile conditions, strength of squeeze injection construction, pressure levels, and interlayer conditions. By repeated perforation with variable intensity, the differences in production profiles can be compensated for, and water blocking pollution in the oil layer can be removed at specific points.

[0021] Furthermore, when repeating the perforation in step S5, the rhythmic effect of the thick oil layer and the longitudinal distribution of the thin interlayer and its effect on the development effect need to be considered when selecting the location for repeated perforation.

[0022] The advantages and positive effects of the present invention are:

[0023] The present invention relates to an integrated process method for water control, oil stabilization, sand control and sand consolidation in thick oil layers (effective thickness ≥ 1.5 meters). Specifically, it relates to a method for deep sand control and sand consolidation in thick oil layers on the basis of water blocking in the layers, and repeated perforation of the top boundary of the oil layer is used to reduce profile interference. The method has the characteristics of simple process, oil increase and sand control, and effectively improves the overall development level of the oil field. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0025] Figure 1 A schematic diagram of a method for tapping potential within a thick oil layer and preventing and consolidating sand provided in Example 1 of the present invention;

[0026] Figure 2 A production curve diagram provided for Example 2 of the present invention;

[0027] Figure 3 A production curve diagram provided for Example 2 of the present invention. DETAILED DESCRIPTION

[0028] First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of example, but all descriptions are only for illustration and should not be understood as limiting the present invention in any way. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature displayed or implied in the drawings, can still be combined or deleted between these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned in this document. In addition, in order to simplify the drawings, the same or similar technical features may be marked only in one place in the same drawing.

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0030] Example 1

[0031] The present embodiment provides a method for tapping potential in thick oil layers and preventing sand from consolidating, comprising the following steps:

[0032] S1. Determine the target layer of the measure, explore the number of layers, oil layer physical properties, fluid properties, energy status, production history and laws, and water content rise characteristics of the target layer of the measure; establish an effective injection channel and create favorable conditions for selective injection (such as diversion, temporary plugging, perforation, relief, and regulation of pressure field distribution);

[0033] S2. Pre-treatment of thick oil layers

[0034] Pretreatment of thick oil layers by squeezing pretreatment agents. The main agent of the pretreatment agent is petroleum sulfonate. According to the formation conditions (such as formation pH, mineralization, etc.), 1-2.55% of polymer, salt, and alkali are compounded to form a multi-component composite oil displacement system;

[0035] After the displacement pretreatment of the thick oil layer, the oil film between the sand particles can be stripped, which is beneficial to the sand control and water blocking of the curing agent. The electrolyte in the pretreatment agent can make the free high-valent particles in the plugging agent form a microcrystalline reinforcement structure, thereby improving the strength of the plugging agent.

[0036] When pre-treating thick oil layers, the following two points should be noted during the treatment process:

[0037] A. According to the oil layer and fluid conditions, there are formation expansion and permeability prevention, crude oil viscosity reduction, unblocking and blockage adjustment, reduction of interfacial tension, improvement of formation wettability, oil displacement and energy enhancement, etc., so the composition of the reagents is not exactly the same;

[0038] B. The injection of oil displacement agent not only needs to improve the fluid and formation during the injection process, but also needs to be driven back after the well measures are taken, so the designed dosage varies greatly;

[0039] After the displacement pretreatment of thick oil layer, it can make:

[0040] A. Pre-clean and dredge the channels that need to be adjusted and blocked, balance the pressure between layers and holes, and facilitate the selective entry of subsequent blocking liquid;

[0041] B. After entering the formation, the dispersed oil droplets in the injection path can be aggregated to form a continuous oil phase, overcoming the Jamin effect, increasing the oil phase permeability, enhancing the oil phase fluidity, and increasing the relative oil production;

[0042] C. It can reduce the surface tension of crude oil on the pore wall and reduce capillary resistance; at the same time, it can promote the gravity separation of oil and water in thick oil layers;

[0043] D. During production, it has the functions of driving back crude oil (oil washing, oil displacement, volume increase, energy increase, viscosity reduction, anti-swelling and shrinkage, wetting and steering), so as to reduce the resistance of crude oil in the pores;

[0044] E. It also has the function of interacting with the plugging agent to improve the efficiency of the plugging agent.

[0045] S3: Deep plugging and sand control and consolidation, giving priority to thick oil layers in the Tertiary strata; this is because:

[0046] A. Shallow burial, loose stratum cementation, under-compaction (easy to produce sand), good oil layer properties (presence of advantageous channels);

[0047] B. The reservoir fluid properties are poor, the crude oil viscosity is high, and the oil-water viscosity ratio is large (the crude oil has poor fluidity, obvious viscosity fingering, the dominant channel is easily flooded, and the crude oil has a strong sand-carrying capacity, which exacerbates sand production);

[0048] C. The formation has sufficient energy. When the water content is high, the daily liquid production is high, the hydrodynamic disturbance is enhanced, the water cone and water channeling are obvious, and the water content rises rapidly. When the flow rate is higher than the critical flow rate (Leiro value), the sand particles in the free jumping aggregate in the formation become suspended aggregates and are carried and produced by water, which intensifies the sand production.

[0049] D. When the thickness of a single layer is greater than 3m, the greater the thickness, the greater the profile heterogeneity. The profile contradiction within the layer is particularly prominent in the Upper Tertiary strata.

[0050] It can be seen that the rising water content, sand production, high crude oil viscosity, contradictory profiles, and high formation energy of the Upper Tertiary strata are mutually influential. Therefore, there is a comprehensive management idea of ​​systematic synergistic improvement of profile control and water plugging, sand control, and viscosity reduction for oil recovery:

[0051] That is, viscosity reduction: making crude oil easier to extract and stripping the oil film between sand particles is beneficial to the sand control and water plugging of the curing agent. The electrolyte in the oil displacement agent can make the free high-valent particles in the plugging agent form a microcrystalline reinforced structure, thereby improving the strength of the plugging agent.

[0052] Water plugging and sand prevention: Water plugging increases the resistance of the dominant channel in the far well area, cements and solidifies the dominant channel in the near well area to reduce water production, makes movable sand particles immobile, blocks the area near the well wall, weakens channeling within the layer, increases the water avoidance height, makes the formation near the well wall resistant to erosion and reduces sand production, and after the overall resistance of the dominant channel is increased, the oil displacement agent entering the deep formation can be effectively driven along the successive channels and parts to improve the recovery efficiency.

[0053] When conducting deep plugging and sand control, suspended and highly selective plugging agents and sand control agents are used under the control and guidance of the pressure field. Large doses of these agents are introduced into the middle and lower parts of thick oil layers, the direction of water advance, and the large pores that are preferentially flooded to achieve deep and selective plugging, thereby achieving the effects of plugging waterways and consolidating formation sand. The selectivity and diversion characteristics of the agents are utilized, and the pressure field guidance technology, namely the hydrodynamic adjustment technology, is introduced, so that the plugging cone profile formed by the plugging agent can effectively compensate for the water cone profile.

[0054] In the present invention, the design concept of the amount of the plugging agent is: Q = (3.14R 2 )N1HN2ΦN3

[0055] Among them, N1 is the area sweep coefficient, that is, the percentage of the water swept area in the well network area in the water injection development reservoir, which is generally 25%-50%; N2 is the thickness sweep coefficient, that is, the ratio of the thickness of the plugging agent swept in the longitudinal direction of the reservoir to the vertical thickness of the reservoir, N2 is generally 1 / 4-1 / 2; N3 is the pore sweep coefficient, that is, the percentage of the pore volume swept by the plugging agent in the reservoir to the total pore volume, N3 is generally 1 / 5-1 / 10; Q is the amount of plugging agent used; R is the plugging radius.

[0056] S4. Reconstruction of artificial well wall

[0057] The thick oil layer of the Upper Tertiary System has good physical properties and a large relative loss during drilling, which will produce a thicker mud cake, thus affecting the cementing of the second interface. The mud cake is not resistant to scouring and migrates with water during the production process, forming obvious channeling channels in the same layer, interfering with the profile output (or there is a risk of channeling within the layer); in this regard, we use high-strength plugging agents to effectively block the water cone channel and the channeling channel and rebuild the wellbore structure; generally, the first water plugging should consider the wellbore reconstruction problem, and repeated tapping within the layer should be determined according to the situation.

[0058] After the wellbore wall is rebuilt, the problems of large pressure drop gradient in the near-wellbore area, erosion-resistant and easy sand production in the formation can be overcome, and sand prevention and consolidation can be achieved; the problem of poor cementing quality can be overcome and secondary cementing can be achieved; the problem of channeling within the layer can be overcome; combined with repeated perforation at selected locations, the water avoidance height can be increased to effectively reduce water.

[0059] When rebuilding the artificial well wall, the production pressure difference is large in the well wall and near the well area. High-strength plugging agents are used to effectively block the water cone channel and the channel channel to rebuild the well wall structure.

[0060] In the near-wellbore area, as the pressure drop increases, the water from the middle and lower parts of the thick oil layer will overcome the gravity and produce water cones, which will interfere with the oil channels in the upper part of the thick oil layer and form obvious profile interference; the thick oil layer has good physical properties and a large relative leakage during drilling, which will produce a thicker mud cake, thereby affecting the cementing of the second interface. The mud cake is not resistant to scouring and migrates with water during the production process, forming obvious same-layer channeling, interfering with profile output; the well wall and near-wellbore area have a large production pressure difference, and high-strength plugging agents should be used to effectively seal the water cone channel and channeling channel to rebuild the well wall structure.

[0061] S5. Repeated perforation can accurately remove pollution, increase water avoidance height, control liquid production speed, and improve development effect;

[0062] When repeated perforating, it is necessary to select layers and locations for variable intensity repeated perforating based on formation conditions, production profile conditions, strength of squeeze injection construction, pressure levels, and interlayer conditions. Variable intensity repeated perforating can compensate for differences in production profiles and remove water plugging pollution in oil layers at targeted locations.

[0063] When repeating perforation, the rhythmic effect of thick oil layers and the vertical distribution of thin interlayers and their impact on development effects need to be considered when selecting locations for repeated perforation. For bottom water reservoirs, if there are continuous mudstone interlayers or physical interlayers inside thick blocky reservoirs and near the oil-water interface, the coning of bottom water will be controlled. There are three conditions for the vertical distribution of interlayers:

[0064] A. Interlayer in water layer

[0065] The interlayer is far away from the oil-water interface and only has a certain inhibitory effect on the upward movement of formation water below the interlayer;

[0066] B. Interlayer near the oil-water interface

[0067] The interlayer is close to the oil-water interface, and its distribution is either above the oil-water interface or below the oil-water interface. This type of interlayer is very important for the development of bottom water reservoirs. It is equivalent to two natural barriers of oil wells, which can inhibit the rising speed of the water cone, extend the water-free oil production period, and improve the ultimate recovery rate.

[0068] C. Interlayer in oil layer

[0069] The interlayer is far away from the oil-water interface. When the water cone reaches the interlayer, it has a certain inhibitory effect on the water cone.

[0070] After plugging, the application of excessive displacement technology, plugging removal or selected layer and location flow-limiting perforation technology can accurately remove oil layer pollution, achieve formation production allocation, and effectively overcome water cones and water channeling; repeated perforation of the top boundary of the oil layer can reduce water cones, achieve sand control, reduce water consumption, and increase oil production.

[0071] The effective thickness of the thick oil layer in the above method is ≥1.5 meters.

[0072] The above method overcomes the singleness of water blocking in thick oil layers, realizes the integration of water blocking and sand control in thick oil layers, and not only has a good sand control effect, but also has the effect of reducing water and increasing oil production while preventing sand, effectively improving the overall development level of the oil field, and having good economic benefits. It has been applied on site in 10 wells with a success rate of 100%.

[0073] Specifically, in this embodiment, Figure 1 As shown:

[0074] ①. The oil displacement slug adopts the oil displacement system to clear the blockage channel, so that the dispersed oil droplets gather to form a continuous oil phase; betaine-type surfactant is squeezed to clear the blockage channel, reduce the oil-water interfacial tension, make the crude oil gather in the upper part of the oil layer, improve the oil phase permeability, and achieve water reduction and oil increase;

[0075] ② The water plugging section plug is squeezed into the plugging agent and the anti-killing agent to the direction of water advance in the thick oil layer and the large pores that are preferentially flooded, forming a plugging cone profile; the heat-resistant and salt-resistant organic gel plugging agent with strong salt tolerance and high plugging rate is injected into the formation with low viscosity, and gelled into a high-strength gel with the help of the formation temperature to plug the large water outlet channel, promote the diversion of liquid flow, and activate the remaining oil potential; at the same time, the sand control agent is added to achieve the purpose of sand control and sand consolidation;

[0076] ③. Use high-strength plugging agent to seal the wellbore and rebuild the wellbore wall to prevent the plugging agent from vomiting back into the wellbore; use ultrafine cement as the main agent, add retarders, suspension dispersants, toughening agents and other additives to improve the interface bonding strength. Plug the blastholes, interlayer channeling grooves and near-wellbore areas to prevent the plugging agent from vomiting back;

[0077] ④. Determine the perforation position by comprehensively considering the rhythmic influence of thick oil layers, the vertical distribution of thin interlayers and their impact on development results.

[0078] Example 2

[0079] This embodiment takes Liu 19-6 as an example: the well is located in Liu 19 block of Liuxi Oilfield in Raoyang Sag of Jizhong Depression;

[0080] The well was put into production in July 2008, with an initial daily production of 8.1 tons of liquid and 2.9 tons of oil, with a comprehensive water content of 63.9%. Currently, the pump is leaking, with a daily production of 18 tons of liquid and 1.96 tons of oil, a water content of 89.2%, a cumulative oil production of 32,650 tons, and a cumulative water production of 153,365m 3 In order to improve the production capacity of the well, it was decided to carry out intra-layer potential tapping and sand control in layer 7.

[0081] On June 17, 2022, the operation team moved to the construction site, washed the original well string on the 19th, washed the sand string on the 22nd, and scraped on the 29th: GX-T140 scraper + 1.53m + 1 D73mm external thickened oil pipe short section + 196 D73mm external thickened oil pipes were placed, and scraped repeatedly 10 times at the 1806-1825.0m section of the well, scraping to 1846.64m; 25m of deoiled formation water was used 3 Reverse circulation well washing, on the 30th, the casing was tested and 190 Y221CY114*58-150 / 50 packers + D73mm external thickened oil pipes were lowered, lifted up one meter and rotated to lower the seat seal, H: 1800.20m, the pump truck pressure was 15MPa, the pressure was stabilized for 30min, the pressure drop was 0MPa, and the casing was qualified. On July 2, the water absorption was measured: the pressure was 2MPa, and the formation water absorption was about 15m per hour 3 ;

[0082] Water plugging on July 3: Priority injection of 100m3 of petroleum sulfonate and its compound 3 Pre-treatment, construction pressure 0-4MPa; add plugging agent A and sand control agent SWD 150m 3 , construction pressure 4-16MPa, top water 6m 3 , stop the pump and shut down the well for 30 minutes, and release the casing pressure to zero. 180 D73mm thickened oil pipes were installed. The well was soaked for 48 hours, and finally the 2FSZ14-21 blowout preventer was installed, and the No. 7 layer was perforated with cables; after the well was opened, the maximum daily oil production was 7 tons, the water content was 29.3%, and the effect of tapping the potential within the layer was obvious. Up to now, the effect of tapping the potential within the layer has continued, with an increase of 2 tons of oil per day, and no sand production was found in the well, indicating that the method of combining tapping the potential within the thick oil layer with sand control and consolidation has been successfully applied in the Liu 19-6 well. Production curve is shown in Figure 2 The well has accumulated 1,087 tons of oil and reduced ineffective liquid production by 11,394 cubic meters. In the same year, the construction of sand prevention and consolidation in the stratum of Liu 19-7 well was carried out, with a maximum daily increase of 7 tons of oil. As of February 25, 2023, the cumulative increase in oil was 765 tons. At present, the well has continued to increase oil production by tapping the stratum, and no sand has been seen. The production curve is shown in Figure 3 .

[0083] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for tapping the potential of thick oil layers and preventing and consolidating sand, characterized in that: The steps include: S1. Determine the target layer of the measure, explore the number of layers, oil layer physical properties, fluid properties, energy status, production history and laws, and water content rise characteristics of the target layer of the measure; establish an effective injection channel and create favorable conditions for selective injection; S2. Pre-treatment of thick oil layers Pre-treat the thick oil layer by squeezing pre-treatment agents. The main agent of the pre-treatment agent is petroleum sulfonate. According to the formation conditions, 1-2.55% of polymer, salt and alkali are compounded to form a multi-component composite oil displacement system. S3, deep plugging and sand control, giving priority to thick oil layers in the Tertiary strata; S4. Reconstruction of artificial well wall S5. Repeated perforation Repeated perforation at the top of the oil layer can reduce the water cone, thereby preventing sand from falling and increasing oil production.

2. The method for sand prevention and consolidation in a layer according to claim 1, characterized in that: in, The effective thickness of thick oil layer is ≥1.5 meters.

3. The method for sand prevention and consolidation in a layer according to claim 1, characterized in that: After the thick oil layer is pre-treated by displacement in step S2, the oil film between the sand particles can be peeled off, which is beneficial to the sand control and water blocking of the curing agent. The electrolyte in the pre-treatment agent can make the free high-valent particles in the blocking agent form a microcrystalline reinforcement structure, thereby improving the strength of the blocking agent.

4. The method for sand prevention and consolidation in a layer according to claim 1, characterized in that: After the deep plugging and sand control in step S3, water blocking increases the resistance of the dominant channel in the far well area, cements and solidifies the dominant channel in the near well area to reduce water production, makes movable sand particles immobile, blocks the area near the well wall, weakens channeling within the layer, increases the water avoidance height, makes the formation near the well wall resistant to scouring and reduces sand production, and after the overall resistance of the dominant channel is increased, the oil displacement agent entering the deep formation is effectively driven along the successive channels and parts to improve the recovery efficiency.

5. The method for sand prevention and consolidation in a layer according to claim 1, characterized in that: When conducting deep plugging and sand control, suspended and highly selective plugging agents and sand control agents are used under the control and guidance of the pressure field to enter the middle and lower parts of the thick oil layers, the direction of water advance and the large pores that are preferentially flooded to achieve deep and selective plugging, thereby achieving the effect of plugging waterways and consolidating formations.

6. The method for tapping potential within a layer to prevent and consolidate sand according to claim 1, characterized in that: When rebuilding the artificial well wall, the production pressure difference between the well wall and the area near the wellbore is large. High-strength plugging agents are used to effectively seal the water cone channel and the channel to rebuild the well wall structure.

7. The method for sand prevention and consolidation in a layer according to claim 1, characterized in that: When repeating the perforation in step S5, it is necessary to select layers and locations for repeated perforation with variable intensity according to formation conditions, production profile conditions, strength of squeeze injection construction, pressure level, and interlayer conditions. By repeated perforation with variable intensity, the difference in production profiles can be compensated and water blocking pollution in the oil layer can be removed at a fixed point.

8. The method for tapping potential within a layer to prevent and consolidate sand according to claim 7, characterized in that: When repeating the perforation in step S5, the rhythmic effect of thick oil layers and the longitudinal distribution of thin interlayers and their influence on the development effect need to be considered when selecting the location for repeated perforation.

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