A sand-carrying liquid base fluid and its application

Abstract

The present invention particularly relates to a sand-carrying liquid base fluid and application thereof, belonging to the technical field of oil extraction. The components of the base fluid include: agent A and agent B; the components of the agent A include: resin binder, curing agent and organic solvent; the components of the agent B include: dispersant, foaming agent, foam stabilizer, coupling agent and solvent; a foam resin with bonding properties is used as an effective component, which carries filling materials to fill cracks and formation deficit zones when used, and the foam resin is adsorbed on the surface of the filling material. After solidification, the filling material is bonded into one, forming an artificial well wall sand barrier, which effectively improves the effect of fracturing and sand prevention.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to a sand-carrying base fluid and application thereof. Background Art

[0002] Unconsolidated sandstone reservoirs are shallow and poorly cemented, making sand production from oil wells a major challenge during development. Conventional sand control completion methods, while preventing sand production from the formation, also limit well productivity, significantly hindering efficient oilfield development. Therefore, to address the issue of sand production limiting production in unconsolidated sandstone reservoirs, Grubert proposed fracturing and filling sand control technology at the end of the last century to control sand production and effectively increase well productivity. Fracturing and sand control technology involves creating fractures through hydraulic fracturing, injecting proppant material into the fractures and formation depletion zones, and sealing these fractures with screens or resin-bonded sand to prevent proppant flowback, creating a sand barrier that serves the dual purpose of sand control and production enhancement. After decades of development and application, this technology has evolved into screen fracturing and sand control, resin-coated sand fracturing and sand control, fiber composite fracturing and sand control, and spray resin fracturing and sand control. It has become one of the most important sand control technologies, with its application expanding year by year.

[0003] As reservoir development conditions become increasingly complex, existing fracturing and sand control technologies are becoming less adaptable. Screen-tube fracturing and sand control require pre-existing screens in the wellbore, hindering subsequent measures. Resin-coated sand fracturing and sand control are costly. Fiber-composite fracturing and sand control have low bonding strength. Spray-coated resin fracturing and sand control require high-performance fracturing fluids, making them prone to sand plugging. Furthermore, existing fracturing and sand control technologies suffer from uneven injection in heterogeneous reservoirs and undersaturated filling and low compaction in severely depleted formations. These issues lead to poor sand control effectiveness and shortened effectiveness, necessitating the development of new fracturing and sand control technologies. Summary of the Invention

[0004] The purpose of this application is to provide a sand-carrying base fluid and its application to solve the problem of poor sand control effect in current oil wells.

[0005] The embodiment of the present invention provides a sand-carrying liquid base fluid, the base fluid comprising: agent A and agent B;

[0006] The components of the agent A include: a resin binder, a curing agent and an organic solvent;

[0007] The components of the agent B include: a dispersant, a foaming agent, a foam stabilizer, a coupling agent and a solvent.

[0008] Optionally, the components of the base liquid include, by mass fraction: resin binder 30%-60%, curing agent 10%-40%, organic solvent 10%-30%, dispersant 0.3%-0.6%, foaming agent 0.3%-0.8%, foam stabilizer 0.4%-1.5%, coupling agent 0.05%-0.2%, and the balance is solvent.

[0009] Optionally, the mass ratio of agent A to agent B is 1:0.8-1.2.

[0010] Optionally, the resin binder is a thermosetting epoxy resin and / or a thermosetting phenolic resin;

[0011] The curing agent is at least one of aliphatic polyamine curing agent, alicyclic polyamine curing agent, aromatic amine curing agent, acid anhydride curing agent, polyamide curing agent, modified amine curing agent and latent curing agent;

[0012] The organic solvent is at least one of acetone, ethanol, ethyl acetate, ethylene glycol monobutyl ether, tetrahydrofuran and chloroform;

[0013] The dispersant is a nonionic surfactant;

[0014] The foaming agent is at least one of sodium α-olefin sulfonate, sodium lauryl sulfate, sodium lauryl sulfonate, sodium dodecylbenzene sulfonate, silicone surfactant, lauramidopropyl betaine, lauramidopropyl hydroxysulfobetaine, cocoyl glutamic acid and cocoamidopropyl betaine;

[0015] The foam stabilizer is at least one of silicone resin polyether, polyethylene glycol PEG, polyvinyl alcohol PVA, hydrophobic nano-SiO2, graphite powder, dolomite powder and carbon dioxide powder;

[0016] The coupling agent is a silane coupling agent;

[0017] The solvent is water.

[0018] Optionally, the resin binder is a thermosetting epoxy resin and a thermosetting phenolic resin, and the mass ratio of the thermosetting epoxy resin to the thermosetting phenolic resin is 1:0.3-0.7; and the curing agent is triethanolamine.

[0019] Based on the same inventive concept, an embodiment of the present invention further provides a sand-carrying fluid, wherein the components of the sand-carrying fluid include, by volume: 40%-80% nitrogen and 20%-60% base liquid; wherein the base liquid is the sand-carrying fluid base liquid described above.

[0020] Based on the same inventive concept, an embodiment of the present invention further provides a fracturing filling sand control material, the components of the fracturing filling sand control material include: a sand-carrying fluid and a filling material, and the sand-carrying fluid is the sand-carrying fluid described above.

[0021] Optionally, the filling material is at least one of quartz sand, ceramsite, slag, calcium carbonate, walnut shell, corundum, manganese sand, zeolite, coke and fiber.

[0022] Based on the same inventive concept, an embodiment of the present invention further provides a fracturing and filling sand control method, the method comprising:

[0023] Conduct formation pretreatment for the well to be treated;

[0024] Performing foam mixing and drainage to remove blockage in the well to be treated after bottom layer pretreatment;

[0025] Carrying sand filling on the well to be treated after the blockage is removed by foam mixing;

[0026] The well to be treated after sand filling is subjected to gas pore expansion, and then shut-in and solidification are performed to complete sand control;

[0027] The sand-carrying filling is carried out using the fracturing filling sand-control material as described above.

[0028] Optionally, the sand-carrying filling is carried out in a graded filling manner.

[0029] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0030] The sand-carrying fluid base fluid provided in an embodiment of the present invention adopts a foam resin with cementing properties as an effective component. When used, the foam resin carries filling materials to fill cracks and formation deficit zones. The foam resin is adsorbed on the surface of the filling material and cements the filling material into one after solidification to form an artificial well wall sand barrier, effectively improving the effect of fracturing and sand prevention.

[0031] 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, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic diagram of the on-site construction process of foam resin fracturing and sand control provided by an embodiment of the present invention;

[0034] Figure 2 1 is a schematic structural diagram of a foam sand mixer provided by an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the pressure difference between the foamed resin sand-carrying fluid and the conventional sand-carrying fluid for gravel packing provided by an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of improving graded filling effect of foam resin provided by an embodiment of the present invention;

[0037] Figure 5 This is a morphology diagram of the foam resin sand-carrying liquid provided by the specific implementation process of the present invention;

[0038] Figure 6 This is a morphology diagram of the foam resin mortar provided by the specific implementation process of the present invention;

[0039] Figure 7 It is a structural schematic diagram of a consolidated core provided by a specific implementation process of the present invention;

[0040] Figure 8 is a flow chart of a method provided by an embodiment of the present invention;

[0041] Figure numerals: 1-foam sand mixer, 11-inner cylinder, 12-outer cylinder, 13-air cavity, 14-nozzle, 15-cone baffle, 16-foam resin inlet, 17-mortar inlet, 18-air inlet, 19-foam sand-carrying liquid outlet, 2-foam generator, 3-cement truck, 4-nitrogen injection truck, 5-first liquid tank truck, 6-fracturing truck, 7-sand mixing truck, 8-sand tank truck, 9-second liquid tank truck. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than for limiting the present invention.

[0043] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event of any conflict, the present specification shall take precedence.

[0044] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0045] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0046] During the invention process, the applicant discovered that foam fracturing is a commonly used fracturing technique in oil fields. The properties of foam fluids can improve the fracturing results of specific wells. However, no reports have been found on foam fracturing sand control technology. Therefore, leveraging the properties of foam fluids to develop foam resin fracturing sand control technology to overcome the limitations of existing fracturing sand control technology is a worthy research direction.

[0047] According to a typical embodiment of the present invention, a sand-carrying liquid base fluid is provided, wherein the base fluid comprises: agent A and agent B;

[0048] The components of the agent A include: a resin binder, a curing agent and an organic solvent;

[0049] The components of the agent B include: a dispersant, a foaming agent, a foam stabilizer, a coupling agent and a solvent.

[0050] Agent A and Agent B are prepared in advance indoors and stored in a sealed container. The separate preparation of Agent A and Agent B facilitates the storage and transportation of the medicines.

[0051] In some embodiments, the components of the base liquid include, by mass fraction: resin binder 30%-60%, curing agent 10%-40%, organic solvent 10%-30%, dispersant 0.3%-0.6%, foaming agent 0.3%-0.8%, foam stabilizer 0.4%-1.5%, coupling agent 0.05%-0.2%, and the balance is solvent.

[0052] In some embodiments, the mass ratio of agent A to agent B is 1:0.8-1.2.

[0053] In some embodiments, the resin binder is a thermosetting epoxy resin and / or a thermosetting phenolic resin; preferably, bisphenol A epoxy resin is used.

[0054] Bisphenol A epoxy resin is a widely used resin binder in the market. It has strong adhesion to various materials, high mechanical strength, and strong chemical resistance. With the addition of a curing agent, it can cure at low temperatures. Bisphenol A epoxy resin has high viscosity and is insoluble in water, requiring dilution with a solvent to facilitate its dispersion in water.

[0055] The curing agent is at least one of aliphatic polyamine curing agent, alicyclic polyamine curing agent, aromatic amine curing agent, acid anhydride curing agent, polyamide curing agent, modified amine curing agent and latent curing agent; preferably, modified aromatic amine curing agent H113 and low molecular weight polyamide curing agent 650 are mixed in a ratio of 1:1, which has high curing strength and controllable curing speed, meeting the sand control construction time requirements.

[0056] The organic solvent is at least one of acetone, ethanol, ethyl acetate, ethylene glycol monobutyl ether, tetrahydrofuran, and chloroform; preferably, ethylene glycol monobutyl ether is used as the solvent. Ethylene glycol monobutyl ether is an excellent solvent with low toxicity and excellent solubility in bisphenol A epoxy resin. The inventors have found in experiments that using ethylene glycol monobutyl ether as a solvent for bisphenol A epoxy resin can significantly improve the epoxy resin's resistance to water inhibition. In combination with a dispersant, the bisphenol A epoxy resin can have good dispersibility in aqueous solution, which is conducive to foaming.

[0057] The dispersant is a nonionic surfactant, which can be selected from OP-10, SP-80, Tween-60, AEO-9, etc. Preferably, OP-10 is used as the dispersant. The dispersant can disperse the resin binder in the form of microparticles in water.

[0058] The foaming agent is at least one of sodium α-olefin sulfonate (AOS), sodium lauryl sulfate (SDS), sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, a silicone surfactant, lauramidopropyl betaine (LAB-35), lauramidopropyl hydroxysulfobetaine (LHSB), cocoyl glutamic acid, and cocoamidopropyl betaine (CAB-35). Preferably, the foaming agent is sodium lauryl sulfate (SDS). Sodium lauryl sulfate (SDS) is adsorbed at the gas / liquid interface, reducing the surface tension between the gas / liquid phases and forming foam.

[0059] The foam stabilizer is at least one of silicone resin polyether, polyethylene glycol (PEG), polyvinyl alcohol (PVA), hydrophobic nano-SiO2, graphite powder, dolomite powder, and carbon dioxide powder. Preferably, the foam stabilizer is a combination of polyethylene glycol (PEG) and hydrophobic nano-SiO2. The polyethylene glycol (PEG) increases liquid phase viscosity, while the nano-SiO2 particles increase foam film strength. The combined use improves foam stability. The polyethylene glycol (PEG) and nano-SiO2 particles can also combine with epoxy resin to enhance the epoxy resin's consolidation strength.

[0060] The coupling agent is a silane coupling agent, which can be specifically selected from KH550, KH560, KH570, KH792, DL602, DL171, etc. Preferably, KH550 is used. The coupling agent can change the surface properties of formation sand particles, increase the affinity of phenolic resin formation sand, and improve the strength of cemented formation sand.

[0061] The solvent is water.

[0062] Preferably, the resin binder is a thermosetting epoxy resin and a thermosetting phenolic resin, and the mass ratio of the thermosetting epoxy resin to the thermosetting phenolic resin is 1:0.3-0.7; and the curing agent is triethanolamine.

[0063] According to another typical embodiment of the present invention, a sand-carrying fluid is provided, wherein the components of the sand-carrying fluid include, by volume: 40%-80% nitrogen and 20%-60% base fluid; wherein the base fluid is the sand-carrying fluid base fluid described above.

[0064] According to another typical embodiment of the present invention, a fracturing filling sand control material is provided. The fracturing filling sand control material comprises: a sand-carrying fluid and a filling material. The sand-carrying fluid is the sand-carrying fluid described above.

[0065] In some embodiments, the filler material is at least one of quartz sand, ceramsite, slag, calcium carbonate, walnut shells, corundum, manganese sand, zeolite, coke, and fiber.

[0066] In some embodiments, a graded filling method is used, first filling with 30 / 50 mesh quartz sand, followed by 20 / 40 mesh coke particles, with a volume ratio of quartz sand to coke of 70:30. The smaller quartz sand at the front end of the fracture enhances sand control against fine silt; the larger, more permeable coke particles at the rear end of the fracture reduce the pressure drop of produced fluids.

[0067] According to another typical embodiment of the present invention, a fracturing and filling sand control method is provided, the method comprising:

[0068] S1. Performing formation pretreatment on the well to be treated;

[0069] Specifically, a cement truck is used to inject pre-fluid into the formation. The pre-fluid uses oilfield sewage or tap water, and is added with oil cleaning agent, anionic foaming agent and anti-swelling agent to clean the oil stains on the surface of the sand particles and at the same time to prevent the clay minerals from swelling.

[0070] S2. Foam mixing and drainage of the well to be treated after pretreatment of the bottom layer;

[0071] Specifically, high-pressure nitrogen is injected using a nitrogen injection truck. When the wellhead pressure reaches 2-10 MPa, the wellhead valve is opened for blowdown, discharging fine silt, argillaceous minerals, and other blockages from the formation. Prepad fluid and high-pressure nitrogen are repeatedly injected and blowdown is performed until the flowback fluid is free of impurities, fully hollowing out the formation surrounding the wellbore. This prevents subsequent filling material from mixing with impurities in the formation, which could lead to a decrease in the permeability of the filling layer.

[0072] S3. The well to be treated after the foam mixed row unblocking is filled with sand; the sand filling is filled with fracturing filling anti-sand material as described above;

[0073] Specifically, Agent A and Agent B are mixed and stirred evenly, and then injected into the foam generator using a cement truck. At the same time, high-pressure nitrogen is injected into the foam generator using a nitrogen injection truck to generate foam resin, which is then injected into the foam sand mixer. At the same time, a mortar mixed with a water-based sand-carrying fluid and filling material (gravel) is injected into the foam sand mixer using a fracturing truck. After passing through the foam sand mixer, the filling material and the foam resin are evenly mixed to generate foam resin mortar, which is then injected into the formation. The cement truck has a construction displacement of 0.3-0.8m 3 / min, the nitrogen injection vehicle has a displacement of 0.5-20m 3 / min, the fracturing truck has a displacement of 0.3-0.6m 3 / min, the volume ratio of gravel to guar gum sand-carrying fluid is 30%-70%.

[0074] S4. Perform gas pore expansion on the well to be treated after sand filling, and then shut in the well for solidification to complete sand control.

[0075] Specifically, high-pressure nitrogen is injected using a nitrogen injection truck to increase the porosity, displace the excess resin bonding between the gravels, and restore the flow channel; the well is then shut down on the ground for 24 hours, and the resin bonding is fully solidified to form an artificial well wall bonding layer, completing the sand control construction.

[0076] The ground processes and foam sand mixing equipment required for the above operations are as follows:

[0077] The ground equipment for on-site construction of foam resin fracturing and sand control includes foam sand mixer, foam generator, cement truck, nitrogen injection truck, first liquid tank truck, fracturing truck, sand mixing truck, sand tank truck and second liquid tank truck.

[0078] The foam sand mixer outlet is connected to the oil wellhead, and the foam resin inlet is connected to the foam generator outlet. The foam generator's air inlet is connected to a nitrogen injection truck, and its liquid inlet is connected to a cement truck. The cement truck is connected to a first liquid tanker. The foam sand mixer's mortar inlet is connected to the fracturing truck outlet, and the fracturing truck's inlet is connected to a sand mixer truck. The sand mixer truck is connected to a sand tanker truck and a second liquid tanker truck, respectively. The foam sand mixer's air inlet is connected to the nitrogen injection truck via a pipeline. The first liquid tanker truck carries the foam resin base liquid, and the second tanker truck carries the water-based sand-carrying fluid.

[0079] The foam sand mixer primarily consists of an inner tube, an outer tube, an air cavity, nozzles, baffle cones, a foam resin inlet, a mortar inlet, an air inlet, and a foam sand-carrying liquid outlet. The outer tube wraps around the inner tube, with an air cavity between the two. Multiple nozzles are installed on the inner tube, connecting the air cavity with the interior of the inner tube. Multiple baffle cones are located inside the inner tube, arranged axially along the inner tube. The foam resin inlet and mortar inlet are three-way connections, connected to one end of the inner tube. The air inlet is located on the outer tube and connects to the interior of the air cavity.

[0080] The foam resin sand-carrying liquid and mortar enter the inner cylinder simultaneously. The impact of the baffle cone creates turbulent agitation. Simultaneously, high-pressure gas is ejected from the nozzle, creating jet agitation. This dual agitation creates a powerful stirring effect between the foam resin sand-carrying liquid and the mortar, achieving uniform mixing and forming foam resin mortar. The baffle cone is designed with a conical structure to significantly reduce erosion and wear caused by sand particles on the baffle cone.

[0081] In some embodiments, sand filling is performed in a staged filling manner.

[0082] Specifically, the fractures are filled first with 30 / 50 mesh quartz sand, followed by 20 / 40 mesh coke particles, with a volume ratio of quartz sand to coke of 70:30. The smaller quartz sand at the front of the fracture enhances sand control against fine silt, while the larger, more permeable coke particles at the rear of the fracture reduce the pressure drop of the produced fluid.

[0083] The sand-carrying liquid base fluid of this application and its application will be described in detail below in combination with the specific implementation process and experimental data.

[0084] At room temperature, take 50 parts of bisphenol A epoxy resin E44, 20 parts of ethylene glycol monobutyl ether, 20 parts of modified aromatic amine curing agent H113 and 20 parts of low molecular weight polyamide curing agent 650, pour them into a container, heat to 50-60℃, stir evenly, fully dissolve, prepare Agent A, and seal for storage.

[0085] Take 97.5 parts of tap water, add 0.2 parts of coupling agent KH550, 0.3 parts of dispersant OP-10, 0.4 parts of foaming agent SDS, 0.5 parts of foam stabilizer polyethylene glycol PEG6000, 1.0 parts of foam stabilizer nano-SiO2, and 0.1 parts of coupling agent KH550, mix and stir, fully dissolve, prepare agent B, and seal for storage.

[0086] The above-mentioned drugs can all be purchased on the market.

[0087] Mix Agent A and Agent B in a ratio of 1:1, and use a stirrer to stir the resulting foam resin sand-carrying liquid (such as Figure 5 The main technical parameters of the foam resin sand-carrying liquid were measured as follows: foaming coefficient 300-700%, foam density 0.35-0.65g / cm 3 , half-life at room temperature is 25h, half-life at 60℃ is 3h.

[0088] Take 120mL foam resin sand-carrying liquid, add 72mL quartz sand proppant (20 / 40 mesh), stir evenly, and prepare foam resin mortar with sand ratio of 60% (such as Figure 6As shown in the figure, it can be seen that the foam resin sand-carrying fluid has good sand-carrying performance. The proppant added to the foam resin sand-carrying fluid can maintain stability for a long time without settling.

[0089] The performance of the foam resin mortar prepared above was evaluated according to the following experimental method:

[0090] (1) Experimental conditions

[0091] a.Φ25×50mm glass tube

[0092] b. Vacuum filtration tester

[0093] c. Constant temperature water bath

[0094] d. Permeability tester

[0095] e.Material mechanics testing machine

[0096] (2) Experimental steps

[0097] a. Place the glass tube into a vacuum filtration instrument and place a metal mesh at the bottom;

[0098] b. The foam resin mortar is loaded into a glass tube, and the foam resin mortar is sucked using a vacuum filtration tester to fill and compact the proppant in the glass tube;

[0099] c. After all the foam resin mortar has been sucked out, continue to suck out air for 10 seconds to increase the pores by gas;

[0100] f. Seal both ends of the glass tube with metal filters and place in a 60°C constant temperature water bath to cure for 12 hours;

[0101] g. Take out the glass tube and break it gently to get the solidified core (such as Figure 7 The two ends were smoothed and the core permeability and compressive strength were tested.

[0102] The performance comparison of cores consolidated with foamed resin sand-carrying fluid and cores consolidated with conventional resin-coated sand is shown in Table 1.

[0103] Table 1 Experimental test results of foam resin and conventional resin coated sand

[0104]

[0105] According to the experimental results, compared with conventional resin-coated sand, the permeability and compressive strength of foam resin consolidated cores are significantly improved.

[0106] The comparison of construction parameters of foam resin fracturing and sand control technology and existing resin-coated sand fracturing and sand control technology is shown in Table 2.

[0107] Table 2 Comparison of foam resin fracturing sand control and resin coated sand fracturing sand control

[0108]

[0109]

[0110] The prepared Agent A and Agent B are placed in different containers and transported to the construction site. The supporting equipment required for the construction site mainly includes 700 cement truck, 1200 nitrogen injection truck, 1m 3 Mixing tank, liquid tank truck, 2000 type fracturing vehicle group, 35MPa pressure foam generator, 35MPa pressure foam sand mixer, etc. Figure 1 The ground construction process is shown as connected.

[0111] Follow the steps below to carry out the construction:

[0112] (1) Formation pretreatment: Use a cement truck to inject pre-flushing fluid into the formation. The pre-flushing fluid is made of oilfield wastewater or tap water, and is added with oil washing agent, anionic foaming agent sodium α-olefin sulfonate and anti-swelling agent KCl to clean the oil stains on the surface of the sand particles and at the same time to prevent the clay minerals from swelling.

[0113] (2) Foam mixing and unblocking: Use a nitrogen injection truck to inject high-pressure nitrogen. When the wellhead pressure reaches 2-10 MPa, open the wellhead valve to release the fine silt, mud minerals and other blockages in the formation. Repeatedly inject pre-fluid and high-pressure nitrogen, and release the foam until there are no impurities in the return fluid. The formation around the wellbore is fully hollowed out to prevent the subsequent filling material from mixing with impurities in the formation, resulting in a decrease in the permeability of the filling layer.

[0114] (3) Foam resin sand filling: Mix Agent A and Agent B evenly, inject them into the foam generator using a cement truck, and inject high-pressure nitrogen into the foam generator using a nitrogen injection truck to generate foam resin, which is then injected into the foam sand mixer. At the same time, a fracturing truck is used to inject a mortar mixed with water-based sand-carrying fluid and filling material (gravel) into the foam sand mixer. After passing through the foam sand mixer, the filling material and foam resin are evenly mixed to generate foam resin mortar, which is then injected into the formation. The construction displacement of the cement truck is 0.3-0.8m 3 / min, the nitrogen injection vehicle has a displacement of 0.5-20m 3 / min, the fracturing truck has a displacement of 0.3-0.6m 3 / min, the volume ratio of gravel to guar gum sand-carrying fluid is 30%-70%.

[0115] (4) Gas pore expansion: Use a nitrogen injection truck to inject high-pressure nitrogen to increase pores, displace excess resin between gravels, and restore flow channels.

[0116] (5) Shut down the well and solidify it: shut down the well on the ground for 24 hours, and then the resin cement will be fully solidified to form an artificial well wall cement layer, thus completing the sand control construction.

[0117] One or more technical solutions in the embodiments of the present invention may have at least the following technical effects or advantages:

[0118] (1) The sand-carrying fluid provided in the embodiment of the present invention is a foam resin sand-carrying fluid. The foam resin sand-carrying fluid itself has a cementing property. The resin cementing agent can be adsorbed on the surface of the gravel and cement the gravel into one body after solidification to form an artificial well wall sand barrier. It can also be filtered into the formation and reinforce the well wall after solidification, thereby playing a dual sand control role and improving the sand control effect.

[0119] (2) The sand-carrying fluid provided by the embodiment of the present invention utilizes the Jamin effect of the foam resin to block the high permeability layer, prevent the fingering phenomenon, increase the injection pressure of the medium and low permeability layers, achieve uniform sand filling of the high, medium and low permeability layers, ensure the sand filling effect of each layer, and improve the overall sand control effect of the heterogeneous oil layer;

[0120] (3) The sand-carrying fluid provided by the embodiment of the present invention utilizes the high pressure difference of the foam resin sand-carrying fluid to enable the filling material to be tightly filled in the cracks and formation deficit zones, achieving saturated filling and improving the degree of compaction, thereby significantly improving the consolidation strength of the filling material and extending the effective period of sand control. Figure 3 As shown;

[0121] (4) The sand-carrying fluid provided by the embodiment of the present invention utilizes the excellent sand-carrying performance of the foam resin to ensure the quality of graded filling, thereby improving the sand control effect and reducing the impact of the sand control layer on production. Figure 4 shown.

[0122] (5) The method provided in the embodiment of the present invention utilizes a foam sand mixer to perform secondary strengthening on the foam, thereby achieving uniform mixing of the foam resin and the solid filling material and improving the foam mixing quality;

[0123] (6) The method provided in the embodiment of the present invention uses conventional gravel instead of resin-coated sand, which can significantly reduce the cost of raw materials.

[0124] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0125] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0126] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A sand-carrying liquid base fluid, characterized in that: The base liquid comprises: agent A and agent B; agent A and agent B are prepared separately; The components of Agent A are as follows: 50 parts of bisphenol A epoxy resin E44, 20 parts of ethylene glycol monobutyl ether, 20 parts of modified aromatic amine curing agent H113 and 20 parts of low molecular weight polyamide curing agent 650. The ingredients of Agent B are: 97.5 parts of tap water, 0.2 parts of coupling agent KH550, 0.3 parts of dispersant OP-10, 0.4 parts of foaming agent SDS, 0.5 parts of foam stabilizer polyethylene glycol PEG6000, 1.0 parts of foam stabilizer nano-SiO2, and 0.1 parts of coupling agent KH550.

2. A sand-carrying fluid, characterized in that: The components of the sand-carrying fluid include, by volume: 40%-80% nitrogen and 20%-60% base fluid; wherein the base fluid is the sand-carrying fluid base fluid described in claim 1.

3. A fracturing filling sand control material, characterized in that: The components of the fracturing filling sand control material include: sand-carrying fluid and filling material, and the sand-carrying fluid is the sand-carrying fluid according to claim 2.

4. The fracturing filling sand control material according to claim 3, characterized in that: The filling material is at least one of quartz sand, ceramsite, slag, calcium carbonate, walnut shell, corundum, manganese sand, zeolite, coke and fiber.

5. A fracturing and filling sand control method, characterized in that: The method comprises: Conduct formation pretreatment for the well to be treated; Performing foam mixing and drainage to remove blockage in the well to be treated after bottom layer pretreatment; Carrying sand filling on the well to be treated after the blockage is removed by foam mixing; The well to be treated after sand filling is subjected to gas pore expansion, and then shut-in and solidification are performed to complete sand control; The sand-carrying filling is carried out using the fracturing filling sand-control material according to any one of claims 3 to 4.

6. The fracturing and filling sand control method according to claim 5, characterized in that: The sand-carrying filling is carried out in a graded filling manner.

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