A high-temperature and high-salt resistant double sand control and water plugging method

Abstract

The present application belongs to the technical field of oil extraction plugging, and relates to a high-temperature and high-salt resistant double sand control water plugging method, comprising the following steps: (1) plugging a high-permeability sand water layer to a stratum by positively pushing a seawater-based intelligent cross-linking sand control water plugging system solution plug, then positively displacing seawater through a tubing and inversely displacing seawater through an oil-casing annulus; (2) plugging a primary wellbore to inject an expansion consolidation system solution plug into a stratum, then positively displacing seawater through a tubing and inversely displacing seawater through an oil-casing annulus; (3) shutting in and waiting for consolidation. The present application adopts a double chemical plugging method for a stratum and a horizontal wellbore, forms an artificial low-permeability zone and a strip-shaped barrier zone, and prolongs a water-free oil production period of a sidetracked new wellbore by more than 40%.

Description

Technical Field

[0001] This invention belongs to the field of oilfield oil production and plugging technology, and relates to a dual sand control and water plugging method resistant to high temperature and high salinity, and particularly to a dual sand control and water plugging method for horizontal wells with high permeability sand and water layers and old wellbores. Background Technology

[0002] Offshore loose sandstone oilfields have a high proportion of reserves and are characterized by high production and high liquid volume. Sand production in oil wells is one of the most common and serious problems faced during the production of high-liquidity loose sandstone oil wells. As most of the major offshore oilfields enter the middle and late stages of development, the problems of water injection, low water levels at the reservoir edge, and high water cut in oil wells are becoming increasingly serious, resulting in a rapid decline in oilfield production and posing a major challenge to the efficient development of oilfields.

[0003] Currently, there are many research results on sand control and water shut-off systems. Mechanical sand control cannot seal the large, high-permeability channels that have already formed within the reservoir, and cannot solve complex problems such as water channeling and rising water cut. Chemical sand control mainly focuses on the performance research of systems with acrylamide and urea-formaldehyde resin as the main components. Due to the high reactivity of acrylamide monomers, polymerization is easily carried out under the action of initiators, resulting in a short gelation time for the system, which is difficult to meet the time requirements of large-scale water shut-off operations. In addition, the gel lacks a rigid structure and will dehydrate and shrink in the formation for a long time, affecting the effectiveness of water shut-off. Furthermore, some water shut-off systems do not have sand control function, and cannot achieve integrated sand control and water shut-off construction.

[0004] Well plugging technology uses two types of materials: cement and expansion consolidation systems. Cement has the following disadvantages: cement particles are large and cannot be injected into the formation; cement has a large filtration loss and is difficult to adjust; cement is prone to shrinkage and poor consolidation; existing expansion consolidation systems have high construction costs, difficulties in agent injection, and are prone to water loss. These factors greatly limit the promotion and application of existing expansion consolidation systems. Summary of the Invention

[0005] To address the problem of poor sealing effect in existing technologies for highly permeable sand-water layers and old wellbores, this invention provides a dual sand control and water plugging method that is resistant to high temperature and high salinity.

[0006] The high-temperature and high-salt resistant dual sand control and water plugging method provided by this invention includes the following steps:

[0007] (1) Blocking the highly permeable sand-water layer

[0008] The solution of the seawater-based intelligent cross-linked sand control and water plugging system is squeezed into the formation, and then the seawater is replaced by the oil pipe and the seawater is replaced by the oil casing annulus.

[0009] (2) Seal the original wellbore

[0010] The expansion and consolidation system solution slug is injected into the formation, and then the seawater is positively displaced through the tubing and negatively displaced through the annulus of the casing.

[0011] (3) Close the well and wait for the condensation to set.

[0012] The above-mentioned high-temperature and high-salt dual sand control and water shut-off method, by weight percentage, comprises: 5%–15% modified polyacrylamide, 5%–15% sodium polymethacrylate, 35%–40% phenolic resin, and 35%–50% triethanolamine.

[0013] In the above-mentioned high-temperature and high-salt dual sand control and water shut-off method, the concentration of the slugs in the seawater-based intelligent cross-linked sand control and water shut-off system solution is 5%-8%, and the concentration increases by 0.5% step by step with the increase of the number of slugs.

[0014] In the above-mentioned high-temperature and high-salt dual sand control and water plugging method, the injection volume of the seawater-based intelligent cross-linked sand control and water plugging system solution slug is 0.005PV to 0.01PV.

[0015] The above-mentioned high-temperature and high-salt dual sand control and water plugging method has a formation action radius of 3-5m for the seawater-based intelligent cross-linked sand control and water plugging system solution slug.

[0016] In the above-mentioned high-temperature and high-salt dual sand control and water shut-off method, in step (1), seawater is positively displaced by an oil pipe for 40-60m. 3 Seawater was replaced by annular displacement of 5-10m through the oil casing. 3 .

[0017] The above-mentioned high-temperature and high-salt dual sand control and water plugging method, by weight percentage, comprises: 40%–55% solid silicate, 20%–30% liquid polyvinyl alcohol, and 17%–35% liquid sodium gluconate.

[0018] In the above-mentioned high-temperature and high-salt dual sand control and water plugging method, the concentration of the expansion consolidation system solution is 10% to 15%, and the concentration increases by 2% with the increase of the number of slugs.

[0019] In the above-mentioned high-temperature and high-salt dual sand control and water plugging method, the injection volume of the solution slug in the above-mentioned expansion consolidation system is 0.0004PV to 0.005PV.

[0020] In the above-mentioned high-temperature and high-salt dual sand control and water shut-off method, in step (2), seawater is positively displaced by an oil pipe for 20-30m. 3 Seawater was replaced by annular displacement of 5-10m through the oil casing. 3 .

[0021] The above-mentioned high-temperature and high-salt dual sand control and water plugging method has a construction pressure of ≤16MPa for the seawater-based intelligent crosslinked sand control and water plugging system solution and ≤25MPa for the expansion consolidation system solution; the injection pressure rise rate is controlled to be 4-10MPa / h during construction.

[0022] In the above-mentioned high-temperature and high-salt dual sand control and water plugging method, the well shut-in and waiting-for-condensation time is 48-72 hours.

[0023] The aforementioned dual sand control and water shut-off method with high temperature and high salinity resistance also includes drilling a side-drilling window at the root of the oil well to obtain an adjustment well.

[0024] The above-mentioned high-temperature and high-salt dual sand control and water plugging method uses seawater to prepare the seawater-based intelligent crosslinked sand control and water plugging system solution and the tough expansion consolidation solution.

[0025] The technical solution of the present invention has the following beneficial effects:

[0026] (1) The present invention adopts a dual chemical plugging method for the formation and horizontal wellbore to form an artificial low-permeability zone and a strip-shaped shielding zone, which extends the waterless oil production period of the new side-drilled wellbore by more than 40%.

[0027] (2) The seawater-based intelligent cross-linked sand control and water plugging system and expansion consolidation system adopted in this invention have technical advantages such as good injection performance, erosion resistance, shear resistance, and high temperature and high salt resistance;

[0028] (3) The high temperature and high salt dual sand control and water plugging method of the present invention realizes the integrated construction of horizontal well sand control and water plugging, saving construction time and cost. Attached Figure Description

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0030] Figure 1 A schematic diagram of the seawater-based intelligent cross-linked sand control and water shut-off system injected into the bottom of the well; where 1 represents the oil layer, 2 represents the tailpipe, 3 represents the seawater-based intelligent cross-linked sand control and water shut-off system, and 4 represents the high-permeability strip.

[0031] Figure 2 This is a schematic diagram of the sealing effect of the seawater-based intelligent cross-linked sand control and water plugging system and the expansion consolidation system; where 5 is the artificial low-permeability isolation zone, 6 is the expansion consolidation system, and 7 is the adjustment well.

[0032] Figure 3 This is a schematic diagram of the high-temperature gelation of the seawater-based intelligent crosslinking sand control and water plugging system of the present invention.

[0033] Figure 4 This is a three-dimensional network structure diagram of the seawater-based intelligent cross-linked sand control and water blocking system of the present invention.

[0034] Figure 5 This is a static gelation curve of the seawater-based intelligent crosslinking sand control and water plugging system of the present invention.

[0035] Figure 6 This is a viscosity retention curve of the seawater-based intelligent crosslinked sand control and water plugging system of the present invention.

[0036] Figure 7 This is a graph showing the experimental data of the sand control performance of the seawater-based intelligent cross-linked sand control and water plugging system of the present invention.

[0037] Figure 8 Temperature-consolidation time curves of three types of solid particles in a seawater-based intelligent cross-linked sand control and water plugging system.

[0038] Figure 9 This is an experimental curve showing the initial setting time of the expansion consolidation system of the present invention.

[0039] Figure 10 This is an experimental curve showing the reduction of filtration loss in the expanded consolidation system of the present invention. Detailed Implementation

[0040] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0041] When a range of values ​​is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0042] To address the problem of poor sealing performance in high-permeability sand-water layers and old wellbores, this invention provides a method for dual sealing of high-permeability sand-water layers and old wellbores in horizontal wells using a seawater-based intelligent cross-linking sand control and water plugging system and an expansion consolidation system.

[0043] Specifically, the high-temperature and high-salt dual sand control and water shut-off method of the present invention includes the following steps: (1) using a seawater-based intelligent cross-linked sand control and water shut-off system solution to seal the high-permeability sand and water layer; (2) using an expansion consolidation system to seal the original wellbore; and (3) shutting in the well and waiting for solidification.

[0044] Figure 1 This is a schematic diagram showing the seawater-based intelligent cross-linked sand control and water shut-off system injected into the bottom of the well. Figure 2 This diagram illustrates the sealing effects of a seawater-based intelligent cross-linked sand control and water shut-off system and an expansion consolidation system. In this diagram, 1 represents the oil layer, 2 the tailpipe, 3 the seawater-based intelligent cross-linked sand control and water shut-off system, 4 the high-permeability strip, 5 the artificial low-permeability isolation zone, 6 the expansion consolidation system, and 7 the adjustment well.

[0045] pass Figure 1-2 As can be seen, this invention achieves integrated sand control and water plugging construction of horizontal wells by using a dual chemical plugging method on the formation and horizontal wellbore to form an artificial low-permeability zone and a strip-shaped shielding zone, thus saving construction time and costs.

[0046] The following is a detailed description of each step of the high-temperature and high-salt-resistant dual sand control and water-blocking method of the present invention:

[0047] (1) Blocking the highly permeable sand-water layer

[0048] The process of sealing highly permeable sand and water layers specifically includes: forcibly injecting a seawater-based intelligent cross-linked sand control and water-blocking system solution into the formation, then replacing the seawater through the oil pipe and replacing the seawater through the annulus of the oil casing.

[0049] Preferably, by weight percentage, the seawater-based intelligent crosslinked sand control and water plugging system comprises: 5%–15% modified polyacrylamide, 5%–15% sodium polymethacrylate, 35%–40% phenolic resin, and 35%–50% triethanolamine.

[0050] The modified polyacrylamide is a sulfonated polyacrylamide with the following molecular formula: [-CH2-CH(CONH2)] x [-CH2-CH(CONHC(C2H6)SO3Na] y The ratio of x:y is 3:1, the average relative molecular weight of the sulfonated polyacrylamide is 400,000, and it was purchased from Jinan Zhongbei Fine Chemical Co., Ltd.

[0051] Sodium polymethacrylate is (C4H6O2). x ·xNa, where X=1-4. CASNO.:54193-36-1.

[0052] Among them, the polyhydroxymethyl groups -CH2OH in phenolic resin and the acrylamide groups -CONH2 in modified polyacrylamide polymer readily undergo condensation reaction to form a three-dimensional cross-linked network structure system (such as...). Figure 4 As shown in the figure, phenolic resin can also inhibit the high-temperature hydrolysis of amide groups on HPAM molecular chains to a certain extent, thereby improving the temperature resistance of the system.

[0053] The seawater-based intelligent crosslinked sand control and water shut-off system solution is prepared using seawater. Preferably, the concentration of the slugs in the seawater-based intelligent crosslinked sand control and water shut-off system solution is 5%-8%, and the concentration increases by 0.5% with the increase of the number of slugs. This allows the agent molecules to penetrate deeply into the oil layer and exhibit oil-water selectivity, reacting extensively on the surface of the water-bearing core to generate supramolecular gels, which bind sand particles to the rock pores, greatly reducing permeability and achieving the dual effects of sand control and water shut-off.

[0054] Preferably, the injection volume of the solution slug in the seawater-based intelligent cross-linked sand control and water plugging system is 0.005PV to 0.01PV, and the formation radius of action is 3-5m.

[0055] Preferably, after the seawater-based intelligent cross-linked sand control and water shut-off system solution is positively extruded into the formation as a sluice, the seawater is positively displaced 40-60m through the oil pipe. 3 Seawater was replaced by annular displacement of 5-10m through the oil casing. 3 .

[0056] The seawater-based intelligent cross-linked sand control and water plugging system of this invention has an aqueous solution that is a low-viscosity free-flowing liquid at room temperature (20-60℃) (injection viscosity <10cp). It can flow deep into the formation along the formation worm channels and form a gel-like substance with certain viscosity strength and temperature and salt resistance under formation conditions (100℃). This gel-like substance is adsorbed and retained in the oil layer channels, ultimately achieving the effect of sand control and water plugging. The initial setting time of the gel-like substance is adjustable from 22 to 35 hours to meet the needs of different plugging construction processes. It is temperature resistant to 100℃ and salt resistant to 50,000-100,000 mg / l. It is erosion resistant. After 100PV water drive, the plugging rate is retained to >90%, the erosion resistance is >97%, and the effective retention time is long.

[0057] The seawater-based intelligent cross-linked sand control and water shut-off system employed in this invention can penetrate deep into the oil reservoir and undergo a chemical reaction in the water-bearing pores to produce a large amount of gel (see...). Figure 3 System architecture characteristics: a dense and ordered three-dimensional spatial network structure, containing typical chain bundles, mesh openings, and nodes (see...). Figure 4 This process aggregates free sand into clumps, blocks high-permeability zones, prevents water from flowing into these zones too quickly, and controls sand production from the reservoir.

[0058] (2) Seal the original wellbore

[0059] The process of sealing the original wellbore specifically includes: injecting an expansion and consolidation system solution into the formation as a slug, and then positively displacing the seawater through the tubing and negatively displacing the seawater through the annulus.

[0060] This invention employs an expansion consolidation system to completely seal off the horizontal section of the original wellbore. This sealing creates a strip-shaped shielding zone with a permeability of 0 mD, thereby blocking the water-flooded area and water body, slowing the rapid rise in water cut, and simultaneously increasing the utilization of remaining potential.

[0061] Preferably, the expansion and consolidation system comprises, by weight percentage: 40%–55% solid silicate, 20%–30% liquid polyvinyl alcohol, and 17%–35% liquid sodium gluconate.

[0062] Among them, the solid silicate is one or more of sodium silicate Na2O·nSiO2 (CAS No.: 13870-30-9), tricalcium silicate 3CaO·SiO2, dicalcium silicate 2CaO·SiO2, and tricalcium aluminate 3CaO·Al2O3 (CAS No: 1327-39-5).

[0063] The chemical formula for liquid polyvinyl alcohol is [C2H4O]. n Where n is 1 to 4. This reagent is a highly transparent aqueous solution, purchased from Guangzhou Ars New Materials Co., Ltd.

[0064] The concentration of liquid polyvinyl alcohol is 0.3-0.5 g / mL; the concentration of liquid sodium gluconate is 0.35-0.4 g / mL.

[0065] The expansion-consolidation system of this invention exhibits good superplastic deformation, good fracture resistance and flexibility, and good creep performance. It also has significant anti-cracking and anti-abrasion properties, is not prone to shrinkage, and expands by 1.4% within 72 hours at 60-100℃. Its pressure resistance reaches 25-40MPa. The compressive strength and permeability of the consolidated body decrease by less than 3% after 3 days at an ambient temperature of 300℃. After hydrolysis, it forms a low-viscosity fluid, which forms a consolidated body with certain strength under reservoir conditions (100℃, 24MPa) with a water loss of <26mL.

[0066] The expansion consolidation system of this invention is mainly used for sealing impermeable environments such as wellbores and formation channels. The slurry prepared by this system has a viscosity of only 10-30 MPa·s at room temperature (20-60℃), which is convenient for construction and has good fluidity. After thickening time >8h, the consistency reaches 100Bc, which has the advantages of high sealing strength, good flexural strength, and temperature and salt resistance.

[0067] The toughening expansion and consolidation solution is prepared using seawater. Preferably, the concentration of the expansion and consolidation system solution is 10% to 15%, and its concentration increases by 2% with the increase of the number of slugs. The injection time is 1 to 2 hours, and the initial solidification time of the system is 5.5 to 10 hours.

[0068] More preferably, the injection volume of the above-mentioned expansion-consolidation system solution slug is 0.0004PV to 0.005PV.

[0069] Preferably, after injecting the expansion and consolidation system solution into the formation via a slug, the present invention positively displaces seawater for 20-30m through the tubing. 3 Seawater was replaced by annular displacement of 5-10m through the oil casing. 3 .

[0070] After the expansion and consolidation system of the present invention is injected into the formation, the changes that occur can be divided into four stages: a) the initial stage, which is mainly a surface reaction, in which the surface of the consolidated particles hydrates, releasing a large amount of heat, and the consolidated body solidifies rapidly. The reaction in this stage is only on the surface of the consolidated particles, consumes very little water, and the consolidated slurry still has relatively good fluidity. b) During the sluggish phase, the hydrated calcium silicate, hydrated calcium ferrite, and hydrated calcium sulfoaluminate gels formed on the surface of the solidified particles have very low permeability, preventing further hydration. At this time, heat release decreases, the hydration rate is very slow, and the fluidity of the solidified slurry remains very good. c) During the setting phase, water begins to penetrate into the particles, hydration accelerates, the hydrates grow and interlock to form a three-dimensional network structure, the solidified slurry gradually loses its fluidity and enters the setting phase. This process generally lasts for tens of minutes, and the final solidified body has a compressive strength in the megapascal range. d) During the hardening phase, hydrates continue to increase, crystals grow and precipitate, and the calcium hydroxide produced by the hydration of a large amount of tricalcium silicate and dicalcium silicate fills the pores. The porosity and permeability of the solidified stone gradually decrease, and the strength gradually increases.

[0071] Further preferably, the construction pressure of the seawater-based intelligent crosslinking sand control and water plugging system solution is ≤16MPa, and the construction pressure of the expansion and consolidation system solution is ≤25MPa. During construction, the injection pressure rise rate is controlled at 4-10MPa / h. Considering the injection dosage (PV) and the gelation time of the plugging agent, the injection discharge rate for this operation is designed to be 45-60m³. 3 The final injection rate and pressure will be determined based on the on-site trial injection results, and the rate of pressure increase during construction should be controlled. On-site construction can be flexibly adjusted according to the actual injection situation, maximizing the discharge rate within the allowable injection conditions.

[0072] (3) Close the well and wait for condensation

[0073] Preferably, the time for shutting in the well and waiting for condensation is 48-72 hours.

[0074] Preferably, the high-temperature and high-salt dual sand control and water shut-off method of the present invention further includes: (4) side-drilling at the root of the oil well to obtain an adjustment well, thereby preventing edge water from being produced through the original wellbore, affecting the waterless oil production period of the new wellbore, and improving the oil well development effect.

[0075] More preferably, the azimuth angle between the adjusted well and the original wellbore trajectory is >45°.

[0076] Example

[0077] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments, unless otherwise specified, are performed according to conventional methods and conditions.

[0078] Example 1

[0079] Reservoir A, a loose sandstone reservoir, is a typical high-porosity, high-permeability reservoir. It is developed using a row-and-column water injection method. Well K1 is a horizontal well in reservoir A, with a horizontal section length of 350m. The reservoir permeability is 800-5000 mD, porosity is 25-34%, effective reservoir thickness is 15m, and reservoir temperature is 100℃. Well K1 was put into production in 2015, initially producing 850 cubic meters of fluid / day and 400 cubic meters of oil / day, with a water cut of 52%. After 8 years of development and production, the cumulative fluid production has reached 155.1 × 10⁻⁶ m³ / day. 4 In some reservoir layers, long-term scouring by water injection has created dominant channels. Simultaneously, influenced by edge water in the northern part of the reservoir, the development layers of the target reservoir are severely water-flooded, with a water cut reaching 98.5%. Furthermore, well K1 has a high daily fluid production, and the reservoir is loosely cemented. On-site pump inspections revealed some sand production in the wellbore. Therefore, chemical sand control and water shut-off measures need to be implemented in well K1, and a sidetracked adjustment well needs to be drilled in the original wellbore.

[0080] The system employed consisted of a seawater-based intelligent cross-linked sand control and water plugging system, comprising 10% sulfonated polyacrylamide (purchased from Jinan Zhongbei Fine Chemical Co., Ltd.), 10% sodium polymethacrylate (where X=2), 36% phenolic resin, and 44% triethanolamine (purchased from Guangzhou Ars New Materials Co., Ltd.). The expansion and consolidation system comprised 50% solid silicate (containing Na2O·nSiO2 and 3CaO·SiO2), 28% liquid polyvinyl alcohol, and 22% liquid sodium gluconate (purchased from Guangzhou Ars New Materials Co., Ltd.), with the concentration of liquid polyvinyl alcohol being 0.3-0.5 g / ml and the concentration of liquid sodium gluconate being 0.35-0.4 g / ml.

[0081] Table 1

[0082]

[0083] First, the injection volume of the seawater-based intelligent cross-linked sand control and water shut-off system solution is designed to be approximately 0.008 PV, and the control volume of this well is... The injection volume of the seawater-based intelligent cross-linked sand control and water plugging system is 1260m³. 3 The injection procedure, which involves gradually increasing the concentration by 0.5% from low to high using a slug pump, is shown in Table 2.

[0084] Table 2 Pumping Procedure for Seawater-Based Intelligent Crosslinked Sand Control and Water Plugging System

[0085]

[0086] Secondly, the designed injection volume of the expansion consolidation system is 0.0004 PV, therefore the injection volume of the expansion consolidation system is 63 m³. 3 The injection concentration was gradually increased by 2% from low to high, and the injection slug pump procedure is shown in Table 3.

[0087] Table 3 Pumping Procedure for Expanded Consolidation System

[0088]

[0089] Finally, a new adjustment wellbore was drilled by side-drilling at the root of the original horizontal wellbore.

[0090] In practice: after side-drilling, the new adjustment well initially produced 450 cubic meters of fluid per day with a water cut of 5%. The sand production at the wellhead was less than 1 / 10,000, achieving good sand control and water shut-off effects, with a cumulative increase in oil production of 12,000 cubic meters.

[0091] Performance testing of water-blocking system

[0092] 1. Seawater-based intelligent cross-linked sand control and water plugging system

[0093] The seawater-based intelligent cross-linked sand control and water plugging system comprises, by weight percentage: 10% sulfonated polyacrylamide (purchased from Jinan Zhongbei Fine Chemical Co., Ltd.), 10% sodium polymethacrylate (where X=2), 36% phenolic resin, and 44% triethanolamine (purchased from Guangzhou Ars New Materials Co., Ltd.).

[0094] 1.1 Temperature and salt resistance test

[0095] A 1% solution of a seawater-based intelligent cross-linked sand control and water plugging system was prepared using water with a mineralization of 30,000 mg / L.

[0096] The seawater-based intelligent crosslinked sand control and water plugging system solution was statically gelled at 120℃. It can be seen that the sealing system has excellent temperature resistance. This system basically cannot gel from room temperature to 60℃ (see...). Figure 5 ).

[0097] The crosslinked system maintains high strength at 120℃; it also maintains high strength at 120℃ under a mineralization of 30000 mg / L, indicating that the system has good temperature and salt resistance (see...). Figure 6 ).

[0098] 1.2 Sand control performance test

[0099] A 7% solution of a seawater-based intelligent cross-linked sand control and water plugging system was prepared using water with a mineralization of 30,000 mg / L.

[0100] Through a single core parallel flow simulation experiment, 245g of quartz sand with a particle size of 0.3-0.6mm and 105g of quartz sand with a particle size of less than 0.1mm were packed into a 30cm×5cm sand-filling pipe. The produced water was saturated at a flow rate of 3mL / min, and then a 1% seawater-based intelligent cross-linked sand control and water-blocking system solution with different PVs was injected in reverse. The system was flushed with clean water at flow rates of 30ml / min, 80ml / min, 100ml / min, and 150ml / min, respectively. When the total flushing flow rate at each flow rate was 4800ml, the sand particles in the flushed liquid were collected, placed in a 120℃ oven for 24 hours, cooled, and weighed.

[0101] Measure the sand output rate under different pump flow rates (see Figure 7 The results showed that the system has high sand control strength, meets the sand control requirements of high-volume offshore oil wells, has a critical sand production flow rate of 100 ml / min, a sand production rate of less than one ten-thousandth, and a critical flow rate increased by 100 times.

[0102] 1.3 Performance Testing of Three Solid Particles

[0103] Take 30.0g of sample and dilute it with 500ml of seawater to the phase transition point of the solution. Take three 100ml portions of the solution and add 50.0g of quartz sand (60-80 mesh), formation sand (60-120 mesh), and clay (greater than 200 mesh) to each portion, respectively. Then pour in 100ml of oilfield produced water, stir gently, and start timing simultaneously to observe the time required for solidification. Measure the consolidation time at different temperatures.

[0104] The higher the temperature, the greater the consolidation rate of the three solid particles in this system. At actual formation temperatures, the agent can rapidly consolidate formation sand (see...). Figure 8 ).

[0105] 2. Expansion-consolidation system

[0106] The expansion-consolidation system comprises, by weight percentage: 50% solid silicate (including Na2O·nSiO2 and 3CaO·SiO2), 28% liquid polyvinyl alcohol, and 22% liquid sodium gluconate (purchased from Guangzhou Ars New Materials Co., Ltd.), wherein the concentration of liquid polyvinyl alcohol is 0.4 g / ml and the concentration of liquid sodium gluconate is 0.37 g / ml.

[0107] 2.1 Initial setting time test

[0108] An expansion and consolidation system solution with a concentration of 12% was prepared using seawater with a mineralization of 30,000 mg / L.

[0109] Pour the expansion and consolidation system solution into the thickener's mud cup and place it on the drive plate inside the autoclave. Then tighten the top cover assembly of the autoclave, insert the temperature sensor through the center hole on the top cover, and screw it in partially. During the test, the solidified body in the mud cup should be heated and pressurized according to the corresponding reservoir parameters. The temperature should be controlled to rise to 120°C within 2 hours and maintained. The pressure should be set at 25 MPa, and the rotation speed at 150 r / min. The thickening time should be measured within the overall temperature range. The thickening time is the time elapsed from the start of heating and pressurization until the consistency reaches 100 Bc.

[0110] The initial setting time curve shows that the initial setting time of this system can be adjusted in a timely manner according to well conditions, ensuring safe construction (see...). Figure 9 ).

[0111] 2.2 Filtration Loss Reduction Test

[0112] An expansion and consolidation system solution with a concentration of 12% was prepared using seawater with a mineralization of 30,000 mg / L.

[0113] The expansion and consolidation system is poured into a high-temperature and high-pressure filter.

[0114] With the pressure valve closed, for a filter cartridge with a length of 25.4 cm, pour the expansion and consolidation system solution into the filter cartridge up to 5.1 cm ± 0.6 cm below the filter screen support.

[0115] Place the filter screen and O-ring into the filtration chamber and secure the end cap to it. Apply a pressure of 3500 kPa ± 300 kPa to the filtration apparatus, without closing the test valve. Open the bottom valve within 30 seconds after inverting the filtration chamber to begin the filtration test. Collect the filtrate and record the filtrate volumes at 55 min, 125 min, 175 min, 250 min, 300 min, and 350 min, accurate to ± 1 mL.

[0116] The filtration loss reduction curve shows that the system has a good filtration loss reduction effect at 90℃, ensuring the success rate of construction (see...). Figure 10 ).

[0117] The present invention has been disclosed above with reference to preferred embodiments. However, those skilled in the art should understand that these embodiments are merely illustrative of the invention and should not be construed as limiting its scope. It should be noted that any variations and substitutions equivalent to these embodiments should be considered to be covered within the scope of the claims. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A dual sand control and water shut-off method resistant to high temperature and high salinity, characterized in that, Includes the following steps: (1) Blocking the highly permeable sand-water layer A seawater-based intelligent cross-linked sand control and water shut-off system solution is injected into the formation via a sluice gate, and then the seawater is positively displaced through the tubing and negatively displaced through the annulus of the casing. The seawater-based intelligent cross-linked sand control and water shut-off system comprises, by weight percentage: 5%–15% modified polyacrylamide, 5%–15% sodium polymethacrylate, 35%–40% phenolic resin, and 35%–50% triethanolamine. (2) Seal the original wellbore An expansion and consolidation system solution is injected into the formation via a sluice gate, and then seawater is positively displaced through the tubing and negatively displaced through the annulus. The expansion and consolidation system comprises, by weight percentage: 40%–55% solid silicate, 20%–30% liquid polyvinyl alcohol, and 17%–35% liquid sodium gluconate. (3) Close the well and wait for it to solidify (4) A well adjustment well is obtained by drilling a window at the root of the oil well.

2. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The concentration of the slugs in the seawater-based intelligent cross-linked sand control and water plugging system is 5%-8%, and the concentration increases by 0.5% with the increase of the number of slugs.

3. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The injection volume of the solution slug in the seawater-based intelligent cross-linked sand control and water plugging system is 0.005PV~0.01PV.

4. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The formation action radius of the solution slug in the seawater-based intelligent cross-linked sand control and water plugging system is 3-5m.

5. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, In step (1), seawater is displaced by tubing 40-60 m 3 , and seawater is displaced by tubing-casing annulus 5-10 m 3 .

6. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The concentration of the expanded solidification system solution is 10%~15%, and the concentration increases by 2% with the increase of the number of slugs.

7. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The injection volume of the above-mentioned expansion-consolidation system solution slug is 0.0004PV~0.005PV.

8. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, In step (2), seawater is positively displaced 20-30m through the oil pipeline. 3 Seawater was replaced by annular displacement via oil casing for 5-10m. 3 .

9. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The construction pressure of the seawater-based intelligent cross-linked sand control and water plugging system solution is ≤16MPa, and the construction pressure of the expansion consolidation system solution is ≤25MPa; the injection pressure rise rate is controlled at 4-10MPa / h during construction.

10. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The time for shutting in the well and waiting for condensation is 48-72 hours.

11. The high-temperature and high-salt resistant dual sand control and water-blocking method according to claim 1, characterized in that, The solution of the seawater-based intelligent cross-linked sand control and water plugging system is prepared using seawater.

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