Modified nano-particles, sand consolidation material, application of sand consolidation material and sand control method for oil and gas well

Abstract

The invention relates to the technical field of oil and gas well sand prevention, in particular to modified nanoparticles, a sand consolidation material, application of the sand consolidation material and an oil and gas well sand prevention method. Based on the weight of the inorganic nanoparticles, the content of the coupling agent chain segment in the modified nanoparticles is 0.1-0.8 wt%, and the content of the organic chain segment in the modified nanoparticles is 30-70 wt%. The sand consolidation material comprises a component A, a component B and a component C, wherein the component A is the modified nanoparticles provided by the invention, and the viscosity of the sand consolidation material at 20-90 DEG C is 10-30 mPa.s. When the sand consolidation material is applied to oil and gas reservoir development, the sand consolidation material not only has very strong adsorption performance on the surfaces of sand grains, but also has very strong cross-linking curing performance, plays a role in gathering, curing, cross-linking and sand consolidation, has small influence on the permeability of rocks, improves the oil yield, and reduces the loss of oil extraction equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of sand control in oil and gas wells, and particularly to a modified nanoparticle, a sand consolidation material and its application, and a sand control method for oil and gas wells. Background Art

[0002] Unconsolidated sandstone oil and gas reservoirs are widely distributed globally with rich reserves and play an important role in the oil and gas extraction industry. Sand production is the main contradiction faced in the development of such oil and gas reservoirs, causing problems such as sand burial of oil layers, wellbore blockage, pump sticking, and frequent maintenance. Most wells need to take sand control measures to ensure normal production.

[0003] Installing a sand control screen pipe downhole is currently the most commonly used sand control measure in the oil and gas industry. Essentially, it constructs a filtration system downhole to prevent formation sand from entering the wellbore. This sand control measure does not fundamentally solve the sand production problem. Formation sand will accumulate outside the screen pipe along with the fluid, causing blockage and resulting in a decrease in the production of oil and gas wells. In addition, for special well conditions such as small hole diameter wells, long well sections, casing deformed wells, separate injection and production wells, etc., the installation and later salvage of the screen pipe are very difficult, and there is a high risk of operation failure.

[0004] The fundamental reason for formation sand production is that sand grains are peeled off from the rock skeleton and produced with the fluid. Theoretically, loose sand grains can be cemented by chemical sand consolidation methods to achieve the purpose of preventing formation sand production and fundamentally solve the formation sand production problem. Moreover, the chemical sand consolidation method has the advantages of simple construction technology, no pipe string left in the wellbore, and low measure cost, and has obvious technical advantages in special well conditions.

[0005] However, currently, the commonly used chemical sand consolidation materials at home and abroad are generally resin-based or modified resin-based. Due to their characteristics such as large molecular weight, high viscosity, non-water-soluble, and high toxicity, these materials have many disadvantages such as great reservoir damage, low consolidation strength, short effective period, and high harmfulness, resulting in limited on-site application scale of chemical sand consolidation technology. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems existing in the existing chemical sand consolidation technology, such as great reservoir damage, low consolidation strength, short effective period, and inapplicability in fine siltstone oil layers. The present invention provides a modified nanoparticle, a sand consolidation material and its application, and a sand control method for oil and gas wells. The sand consolidation material contains the modified nanoparticle, and the modified nanoparticle has an inorganic nanoparticle core and an organic modification layer. When applied to oil and gas wells, it can not only improve the mechanical properties of formation rocks, have high cementation strength, but also adapt to fine siltstone oil layers and achieve a better sand consolidation effect.

[0007] To achieve the above object, a first aspect of the present invention provides a modified nanoparticle for sand control in oil and gas wells, wherein the modified nanoparticle comprises an inorganic nanoparticle core, a coupling agent segment grafted on the particle surface, and an organic segment grafted on the particle surface or / and on the coupling agent; wherein, based on the weight of the inorganic nanoparticle, the content of the coupling agent segment is 0.1-0.8 wt%, and the content of the organic segment is 30-70 wt%.

[0008] A second aspect of the present invention provides a sand consolidation material, which comprises component A, component B and component C;

[0009] Wherein, the component A is the modified nanoparticle described in the first aspect.

[0010] A third aspect of the present invention provides an application of the sand consolidation material described in the second aspect in oil and gas reservoir development.

[0011] A fourth aspect of the present invention provides a sand control method for oil and gas wells, the method comprising:

[0012] (1) Injecting the sand consolidation material into the sand-producing layer of the oil and gas well;

[0013] (2) Then injecting a displacement fluid into the sand-producing layer;

[0014] Wherein, the sand consolidation material is the sand consolidation material described in the second aspect.

[0015] Through the above technical solution, the modified nanoparticle of the present invention comprises an inorganic nanoparticle core, a coupling agent segment grafted on the particle surface, and an organic segment grafted on the particle surface or / and on the coupling agent, and a small molecule organic segment with reactive activity and water solubility is introduced on the surface of the inorganic nanoparticle by grafting modification. On the one hand, the unsaturated property of the inorganic nanoparticle is retained; on the other hand, the reactive activity of the inorganic nanoparticle is increased. As can be seen from the schematic diagram of the adsorption and curing of the sand consolidation material on the sand grain surface shown in Figure 1 When the modified nanoparticle is mixed with a curing agent and used as a sand consolidation material in oil and gas reservoir development, the adsorption performance of the nanoparticle is utilized to automatically adsorb and aggregate on the surface of the formation sand; the surface activity of the nanoparticle is utilized, and the epoxy group in the small molecule organic segment undergoes a ring-opening reaction with the active hydrogen functional group in the curing agent, and cures to form a very thin nanoparticle aggregation network under the action of the formation temperature, crosslinking into a three-dimensional structure, so that it has both strong adsorption performance and strong crosslinking and curing performance, playing a role in aggregating, curing and crosslinking sand consolidation; the nanoparticles precipitate from the aqueous solution, and the aqueous solution occupies the rock pores, avoiding pore blockage and having little influence on the rock permeability. As can be seen from Table 1 and Table 2, the consolidated core obtained by using the sand consolidation material of the present invention has a relatively high strength, and also has good permeability in fine silt. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the adsorption and curing of the sand-fixing material on the surface of sand grains. Detailed implementation manners

[0017] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0018] The following will detail the specific implementation manners of the present invention. It should be understood that the specific implementation manners described herein are only for explaining and interpreting the present invention, and are not used to limit the present invention.

[0019] The first aspect of the present invention provides a modified nanoparticle for sand control in oil and gas wells. The modified nanoparticle includes an inorganic nanoparticle core, a coupling agent segment grafted on the particle surface, and an organic segment grafted on the particle surface or / and on the coupling agent. Wherein, based on the weight of the inorganic nanoparticle, the content of the coupling agent segment is 0.1-0.8 wt%, and the content of the organic segment is 30-70 wt%.

[0020] According to the present invention, the coupling agent segment and the organic segment are adsorbed on the surface of the nanoparticle by a grafting modification method. The epoxy groups in the organic modified outer layer undergo a ring-opening reaction with the active hydrogen functional groups in the curing agent and crosslink into a three-dimensional structure to connect the nanoparticle cores and form a high-strength curing layer. Based on the weight of the inorganic nanoparticle, the content of the organic segment is 30-70 wt%. When the proportion is less than 30%, the cementing strength is affected. When the proportion is greater than 70%, the adsorption activity of the nanoparticle is affected. In other words, on the one hand, the modified nanoparticle of the present invention retains the unsaturated characteristics of the inorganic nanoparticle; on the other hand, it increases the reaction activity of the inorganic nanoparticle, making this type of nanoparticle have both strong adsorption performance and strong crosslinking and curing performance.

[0021] According to the present invention, in order to control the grafting rate of the small molecule organic matter on the surface of the inorganic nanoparticle and make the modified nanoparticle have both strong adsorption performance and strong crosslinking and curing performance, preferably, based on the weight of the inorganic nanoparticle, the content of the organic segment is 45-60 wt%.

[0022] According to the present invention, in order to improve the water solubility of the modified nanoparticle, preferably, the substance providing the organic segment is a small molecule organic matter with a molecular weight ≤ 500 g / mol.

[0023] Further preferably, the small molecule organic compound is selected from one or more of 4-vinylcyclohexene oxide, allyl polyoxyalkylene epoxy ether, cyclohexyltrimethylsilane, epoxy cage-like silsesquioxane, methyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, phenyltrimethoxysilane; more preferably, it is 4-vinylcyclohexene oxide and / or allyl polyoxyalkylene epoxy ether.

[0024] According to the present invention, in order to improve the adsorption performance between the inorganic nanoparticles and the surface of the sand grains, as well as the adhesion of the organic chain segments to the core of the inorganic nanoparticles, preferably, the substance providing the coupling agent segment is a silane coupling agent. The Si(OCH2) group in the silane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the sand grains under certain conditions to form a strong silicon-oxygen bond, and the other end is connected to the active groups of the organic modified outer layer, thereby greatly improving the adhesion of the organic modified outer layer to the core of the nanoparticles.

[0025] More preferably, the coupling agent is selected from one or more of aminopropyltriethoxysilane, methyltriethoxysiloxane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0026] According to the present invention, in order to avoid blocking the voids during oil and gas production and improve the rigidity of the sand consolidation bonding layer and the permeability of the rock, preferably, the average particle size of the inorganic nanoparticles is 10 - 100 nm. The core of the nanoparticles serves as a carrier for the small molecule organic cross-linking agent, which can transport the small molecule organic compound to the micro pores or micro fractures of the rock, and automatically adsorb on the surface of the formation sand by utilizing the surface activity of the nanoparticles. When the small molecule organic compound undergoes cross-linking and curing, the core of the nanoparticles can play a strengthening role, greatly enhancing the cementation strength of the cured film.

[0027] Preferably, the inorganic nanoparticles are selected from one or more of nano-silica, nano-carbon fiber, carbon nanotube, nano-titanium oxide, nano-aluminum oxide; when the core of the nanoparticles is a mixture of multiple substances, the ratio is arbitrary.

[0028] Further preferably, the inorganic nanoparticles are nano-silica.

[0029] According to the present invention, in order to avoid blocking the voids during oil and gas production and improve the rigidity of the sand consolidation bonding layer and the permeability of the rock, preferably, the average particle size of the modified nanoparticles ≤ 1000 nm.

[0030] The present invention does not particularly limit the preparation method of the modified nanoparticles, as long as the modified nanoparticles with the above composition and structure can be obtained. According to a preferred embodiment of the present invention, the modified nanoparticles can be prepared by the following method, and the specific steps include:

[0031] (a) Mix the silane coupling agent, absolute ethanol and pure water, and adjust the pH to 3 - 4 to obtain a hydrolyzed solution of the silane coupling agent;

[0032] (b) Mix the hydrolyzed solution of the silane coupling agent with inorganic nanoparticles, stir, perform ultrasonic dispersion treatment, and adjust the pH to neutral to obtain a pretreated solution of the nanoparticles;

[0033] (c) Mix the pretreated solution of the nanoparticles with small - molecule organic substances, add a catalyst, inject nitrogen for protection, and stir and react to obtain the modified nanoparticles.

[0034] Among them, in step (a), there is no special limitation on the substance for adjusting the pH, as long as the acidity and alkalinity of the mixture of the silane coupling agent, absolute ethanol and pure water are adjusted to 3 - 4.

[0035] Preferably, in step (a), the substance for adjusting the pH is acetic acid.

[0036] In step (b), in order to better treat the inorganic nanoparticles and make the particle surface fully coated with the coupling agent, preferably, the weight ratio of the inorganic nanoparticles to the silane coupling agent is 1:0.05 - 0.06.

[0037] In step (b), there is no special limitation on the substance for adjusting the pH, as long as the pH value of the mixture is adjusted to neutral and the added substance does not react with the inorganic nanoparticles; preferably, in step (b), the substance for adjusting the pH is sodium bicarbonate.

[0038] Preferably, in step (c), the temperature of the reaction is 60 - 80 °C and the time is 1 - 2 h.

[0039] In order to control the grafting rate of the small - molecule organic substances on the surface of the inorganic nanoparticles, so that the modified nanoparticles have both strong adsorption performance and strong cross - linking and curing performance, preferably, in step (c), the weight ratio of the small - molecule organic substances, the catalyst and the inorganic nanoparticles is 20 - 40:0.1 - 0.8:100.

[0040] Preferably, in step (c), the catalyst is azobisisobutyronitrile, cerium oxide or sodium caprolactam.

[0041] The structure of the modified nanoparticles of the present invention can be tested and obtained by means of a laser particle size analyzer, infrared spectroscopy and scanning electron microscopy.

[0042] The composition of the modified nanoparticles of the present invention can be tested and obtained by infrared spectroscopy, nuclear magnetic resonance spectroscopy and spectral analysis, or calculated from the feed amount.

[0043] The second aspect of the present invention provides a sand consolidation material, which comprises component A, component B and component C;

[0044] Among them, the component A is the modified nanoparticle described in the first aspect.

[0045] Preferably, the component B is a curing agent.

[0046] More preferably, the component B is a water-soluble epoxy resin.

[0047] In the present invention, the water-soluble epoxy resin can be a commercially available product or prepared by existing methods.

[0048] Preferably, the water-soluble epoxy resin is one or more of ZW-6112 waterborne epoxy curing agent, DP-03 waterborne epoxy curing agent, CYDHD-220 waterborne epoxy curing agent, and SAC8325 waterborne epoxy curing agent.

[0049] More preferably, the component B can also be a mixture of polyetheramine and methanol, and the weight ratio of the two is 100∶(5-20).

[0050] In the present invention, the polyetheramine can be a commercially available product or prepared by existing methods.

[0051] Preferably, the model of the polyetheramine can be D230, D400, or D2000.

[0052] Preferably, the component C is a clay anti-swelling agent, which is mainly used to prevent the swelling of clay minerals in formation rocks.

[0053] Preferably, the component C is an aqueous solution of a clay anti-swelling agent, with a concentration of 1-5 wt%.

[0054] More preferably, the clay anti-swelling agent is selected from one or more of KCl, organic quaternary ammonium salts, and organic cationic polymers.

[0055] Preferably, the organic quaternary ammonium salt is polyhydroxypropyl dimethyl ammonium chloride.

[0056] Preferably, the organic cationic polymer is cationic polyacrylamide.

[0057] Preferably, in the sand consolidation material, the weight ratio of component A, component B, and component C is 1∶(0.2-1)∶(1-10).

[0058] More preferably, in the sand consolidation material, the weight ratio of component A, component B, and component C is 1∶(0.2-0.5)∶(2-6).

[0059] Preferably, the viscosity of the sand consolidation material is 10 - 30 mPa·s.

[0060] Preferably, the sand consolidation strength of the sand consolidation material is ≥ 8 MPa.

[0061] Preferably, the sand consolidation permeability of the sand consolidation material is ≥ 2 μm.

[0062] The present invention does not particularly limit the preparation method of the sand consolidation material, as long as the sand consolidation material with the above composition and properties can be obtained. According to a preferred embodiment of the present invention, the sand consolidation material can be prepared by the following method, and the specific steps include: mixing component A, component B, and component C according to a weight ratio of 1:(0.2 - 1):(1 - 10) to obtain the sand consolidation material.

[0063] Preferably, in order to uniformly disperse the component A modified nanoparticles, the step of stirring is further included after the mixing. More preferably, the stirring speed is 200 - 1000 rpm and the time is 5 - 30 min; or, the step of ultrasonic dispersion treatment is further included after the mixing. More preferably, the time of the ultrasonic dispersion treatment is 10 min.

[0064] The downhole environment for sand control in oil and gas wells is generally: water cut of 30 - 99%, sand particle size of 0.05 - 0.35 mm, and oil reservoir permeability of 0.1 - 3 μm 2 and formation temperature of 30 - 120 °C.

[0065] The sand control of the present invention for oil and gas wells refers to using the nanoparticle core as the carrier of the organic chain segments, which needs to penetrate into the fine pores of the rock along with clear water, transport the organic chain segments to the fine pores or microfractures of the rock, and form a very thin nanoparticle aggregation network under the action of the curing agent and formation temperature. It not only plays the role of aggregating, curing, and crosslinking to consolidate the sand, but also does not block the pores and has little impact on the rock permeability.

[0066] The third aspect of the present invention provides an application of the sand consolidation material described in the second aspect in the development of oil and gas reservoirs.

[0067] The fourth aspect of the present invention provides a method for sand control in oil and gas wells, and the method includes:

[0068] (1) Injecting the sand consolidation material into the sand-producing layer of the oil and gas well;

[0069] (2) Then injecting a displacement fluid into the sand-producing layer;

[0070] wherein, the sand consolidation material is the sand consolidation material described in the second aspect.

[0071] According to the sand control method described above, in order to adjust the injection profile between different oil layers, facilitate the uniform injection of the nano-particle sand control material into different oil layers, achieve uniform sand consolidation, improve the sand consolidation effect and the effective period of the entire well section, preferably, the sand control method further includes: before step (1), injecting a profile control and plugging agent into the sand-producing layer, preferably a gel profile control agent; more preferably, the profile control and plugging agent includes a polymer thickening agent and a gel breaker.

[0072] Even more preferably, the gel profile control agent is an aqueous solution containing a polymer thickening agent and a gel breaker. The polymer thickening agent refers to a polymer organic substance that can increase the viscosity of clear water, and there is no limit to its type. It can be guar gum powder, and its concentration in the gel profile control agent is 0.2-0.8 wt%; the gel breaker refers to a substance that can degrade the polymer thickening agent, and there is no limit to its type. It can be ammonium persulfate, and its concentration in the gel profile control agent is 0.1-0.3 wt%.

[0073] According to the sand control method described above, in order to clean the crude oil on the surface of formation sand grains, dredge the formation pores, facilitate the adsorption of nano-particles on the sand grain surface, avoid the influence of crude oil on the consolidation strength, and at the same time prevent clay hydration swelling and cause reservoir damage, preferably, the sand control method further includes: before injecting the profile control and plugging agent into the sand-producing layer, treating the sand-producing layer with a treatment fluid; more preferably, the treatment fluid includes an oil-washing agent and an anti-swelling agent.

[0074] Even more preferably, the treatment fluid is an aqueous solution containing an oil-washing agent and an anti-swelling agent. The oil-washing agent refers to a surfactant that can clean the crude oil on the sand grain surface and dredge the channels, and there is no limit to its type. It can be α-olefin sulfonate (AOS), and its concentration in the treatment fluid is 0.5-5 wt%; the anti-swelling agent refers to a substance that can inhibit the swelling of clay minerals, and there is no limit to its type. It can be KCl, and its concentration in the treatment fluid is 2-4 wt%.

[0075] According to the sand control method of the present invention, during the development process of the oil and gas reservoir, in order to make the small molecule organic substances in the modified nano-particles react completely with the curing agent, connect the inorganic nano-particle cores, and form a high-strength curing layer, preferably, the sand control method further includes: after step (2), shutting in the well for curing;

[0076] More preferably, the temperature for shutting in the well for curing is 50-90 °C, and the time is 12-48 h.

[0077] By utilizing the adsorption performance and reactivity of modified nanoparticles, the modified nanoparticles freely dispersed in the aqueous solution can penetrate into the micro pores of the rock along with the clear water; by utilizing the surface activity of the nanoparticles, they can be automatically adsorbed and aggregated on the surface of formation sand grains, and cured under the action of a curing agent and formation temperature to form a very thin nanoparticle aggregation network, playing the role of aggregating, curing and crosslinking sand consolidation. The nanoparticles precipitate from the aqueous solution and adsorb on the surface of the sand grains, and the aqueous solution occupies the rock pores, avoiding pore plugging and having little impact on the rock permeability.

[0078] According to the sand control method of the present invention, in order to achieve a better sand control effect, preferably, in the sand consolidation material, the dosage of the sand consolidation material can be calculated according to formula (1):

[0079] V = πr 2 φh Formula (1)

[0080] Wherein, V is the dosage of the sand consolidation material, in m 3 ; r is the radius of the sand consolidation range of the oil well, preferably 0.3 - 1 m; φ is the porosity of the oil reservoir, preferably 5 - 40%; h is the thickness of the sand production layer, preferably 1 - 20 m.

[0081] Preferably, the dosage V of the sand consolidation material is 0.01 - 25 m 3 .

[0082] The present invention will be described in detail below through examples, wherein the room temperature is 15 - 35 °C.

[0083] Component B1 is the CYDHD-220 waterborne epoxy curing agent of Baling Petrochemical.

[0084] Component B2 is a mixture of polyetheramine and methanol, wherein the weight ratio of polyetheramine to methanol is 5:1.

[0085] Example 1

[0086] Preparation method of sand consolidation material

[0087] (1) Preparation of component A:

[0088] Mix 5 g of silane coupling agent 3-aminopropyltriethoxysilane (KH550), 80 g of absolute ethanol and 15 g of clear water, and adjust the pH to 3 with acetic acid to obtain a coupling agent hydrolysis solution;

[0089] Mix 100 g of nano-SiO2 (average particle size of 70 nm) and 200 g of the coupling agent hydrolysis solution, stir evenly, put it into an ultrasonic processor, disperse for 30 min, dropwise add NaHCO3, and adjust the pH to 7 to obtain a nanoparticle pretreatment solution;

[0090] Heat 20 g of 4-vinylcyclohexene oxide to 40 °C, add the prepared nano-particle pretreatment solution and 0.1 g of catalyst azobisisobutyronitrile, stir, and then heat to 60 °C. React for 2 h to obtain Component A, defined as modified nano-particle 1;

[0091] Perform laser particle size analysis test on modified nano-particle 1. According to the test results, the average particle size of modified nano-particle 1 is 72 nm; perform infrared spectrum test on modified nano-particle 1. According to the test results, based on the weight of the inorganic nano-particles, the content of the coupling agent segment is 0.5 wt%, and the content of the organic segment is 40 wt%;

[0092] (2) Add KCl to clear water and stir evenly to obtain Component C with a concentration of 4%;

[0093] (3) Mix Component A, Component B1, and Component C according to a weight ratio of 1:0.5:2, and stir at a speed of 200 - 1000 rpm for 30 min to obtain sand consolidation material 1;

[0094] Perform viscosity test on sand consolidation material 1. According to the test results, the viscosity of sand consolidation material 1 at 60 °C is 8 mPa·s.

[0095] Example 2

[0096] Preparation method of sand consolidation material

[0097] (1) Preparation of Component A:

[0098] Mix 5 g of silane coupling agent 3-aminopropyltriethoxysilane (KH550), 80 g of absolute ethanol, and 15 g of clear water, and adjust the pH to 4 with acetic acid to obtain the coupling agent hydrolysis solution;

[0099] Mix 100 g of nano-SiO2 (average particle size of 50 nm) and 200 g of the coupling agent hydrolysis solution, stir evenly, put it into an ultrasonic processor, perform dispersion treatment for 30 min, add NaHCO3 dropwise, and adjust the pH to 7 to obtain the nano-particle pretreatment solution;

[0100] Heat 40 g of 4-vinylcyclohexene oxide to 60 °C, add the prepared nano-particle pretreatment solution and 0.14 g of catalyst azobisisobutyronitrile, stir, and then heat to 80 °C. React for 1 h to obtain Component A, defined as modified nano-particle 2;

[0101] Perform laser particle size analysis test on modified nano-particle 2. According to the test results, the average particle size of modified nano-particle 2 is 56 nm; perform infrared spectrum test on modified nano-particle 2. According to the test results, based on the weight of the inorganic nano-particles, the content of the coupling agent segment is 0.7 wt%, and the content of the organic segment is 60 wt%;

[0102] (2) Add KCl to clear water and stir evenly to obtain Component C with a concentration of 4%.

[0103] (3) Mix Component A, Component B1, and Component C according to a weight ratio of 1:0.5:2, and stir at a speed of 200 - 1000 rpm for 30 min to obtain Sand Consolidation Material 2.

[0104] Perform a viscosity test on Sand Consolidation Material 2. According to the test results, the viscosity of Sand Consolidation Material 2 at 60 °C is 15 mPa·s.

[0105] Example 3

[0106] Preparation method of sand consolidation material

[0107] (1) Preparation of Component A:

[0108] Mix 5 g of silane coupling agent 3-aminopropyltriethoxysilane (KH550), 80 g of absolute ethanol, and 15 g of clear water, and adjust the pH to 3 with acetic acid to obtain a coupling agent hydrolysis solution.

[0109] Mix 100 g of nano-SiO2 (average particle size of 70 nm) and 200 g of the coupling agent hydrolysis solution, stir evenly, put it into an ultrasonic processor, perform dispersion treatment for 30 min, add NaHCO3, and adjust the pH to 7 to obtain a nano-particle pretreatment solution.

[0110] Heat 20 g of allyl polyoxyalkylene epoxy ether to 40 °C, add the prepared nano-particle pretreatment solution and 0.1 g of catalyst azobisisobutyronitrile, stir, and heat to 60 °C, and react for 2 h to obtain Component A, defined as Modified Nano-Particle 3.

[0111] Perform laser particle size analysis test on Modified Nano-Particle 3. According to the test results, the average particle size of Modified Nano-Particle 3 is 72 nm; perform infrared spectrum test on Modified Nano-Particle 3. According to the test results, based on the weight of the inorganic nano-particles, the content of the coupling agent segment is 0.56 wt%, and the content of the organic segment is 53 wt%.

[0112] (2) Add KCl to clear water and stir evenly to obtain Component C with a concentration of 4%.

[0113] (3) Mix Component A, Component B1, and Component C according to a weight ratio of 1:0.5:2, and stir at a speed of 200 - 1000 rpm for 30 min to obtain Sand Consolidation Material 3.

[0114] Perform a viscosity test on Sand Consolidation Material 3. According to the test results, the viscosity of Sand Consolidation Material 3 at 60 °C is 18 mPa·s.

[0115] Example 4

[0116] Preparation method of sand consolidating material

[0117] (1) Preparation of component A:

[0118] Mix 5 g of silane coupling agent 3-aminopropyltriethoxysilane (KH550), 80 g of absolute ethanol and 15 g of clear water, and adjust the pH to 3 with acetic acid to obtain a coupling agent hydrolysis solution;

[0119] Mix 100 g of nano-SiO2 (average particle size of 70 nm) and 200 g of the coupling agent hydrolysis solution, stir evenly, put it into an ultrasonic processor, disperse for 30 min, dropwise add NaHCO3, and adjust the pH to 7 to obtain a nano-particle pretreatment solution;

[0120] Heat 20 g of 4-vinylcyclohexene oxide to 40 °C, add the prepared nano-particle pretreatment solution and 0.1 g of catalyst azobisisobutyronitrile, stir, and heat to 60 °C, react for 2 h to obtain component A, defined as modified nano-particle 4;

[0121] Carry out laser particle size analysis test on modified nano-particle 4. According to the test results, the average particle size of modified nano-particle 4 is 72 nm; carry out infrared spectrum test on modified nano-particle 1. According to the test results, based on the weight of the inorganic nano-particles, the content of the coupling agent segment is 0.5 wt%, and the content of the organic segment is 40 wt%;

[0122] (2) Add KCl to clear water, stir evenly to obtain component C with a concentration of 4%;

[0123] (3) Mix component A, component B2, and component C according to a weight ratio of 1:0.5:2, stir at a speed of 200 - 1000 rpm for 30 min to obtain sand consolidating material 4;

[0124] Carry out viscosity test on sand consolidating material 1. According to the test results, the viscosity of sand consolidating material 1 at 60 °C is 13 mPa·s.

[0125] Comparative Example 1

[0126] Phenolic resin sand consolidating agent, including: 60 g of phenolic resin (model 219, commercially available), 40 g of ethanol, 90 g of water and 10 g of curing agent NL.

[0127] Comparative Example 2

[0128] Epoxy resin curing agent, including: 60 g of epoxy resin (model E44, commercially available), 80 g of ethanol and 10 g of curing agent T31.

[0129] Test Example

[0130] The sand-fixing materials prepared in the examples were evaluated for sand control performance against the phenolic resin sand-fixing agent provided in Comparative Example 1 and the epoxy resin curing agent provided in Comparative Example 2. The specific method includes:

[0131] (1) One end of a Φ25×50 mm glass tube was connected to a vacuum filtration device to form a sand-fixing experimental device; 20 g of formation sand (sand grain size 20 - 40 mesh) was loaded into the Φ25×50 mm glass tube, the vacuum pump was started for filtration, clear water was poured in to wet the formation sand, and then the sand-fixing material prepared in the example was poured in to completely immerse the formation sand, and the filtration was stopped; both ends of the glass tube were sealed and fixed with a clamp to keep the formation sand in a compacted state, placed in a water bath, the temperature was set at 50 °C, after curing for 24 h, it was taken out, the glass tube was broken, and a consolidated core was obtained;

[0132] (2) Consolidated cores of different formation sands were prepared in the same method, wherein the particle sizes of the formation sands were 40 - 70 mesh, 60 - 80 mesh, 100 - 200 mesh, and 150 - 260 mesh respectively;

[0133] (3) Consolidated cores of phenolic resin sand-fixing agent and epoxy resin sand-fixing agent were prepared in the same method.

[0134] According to the method of SY / T 5276 - 2000 "Test Method for Flexural Strength, Compressive Strength and Permeability of Chemical Sand Control Artificial Cores", the permeability of the consolidated cores was tested, and the data results are shown in Table 1.

[0135] According to the method of SY / T 5276 - 2000 "Test Method for Flexural Strength, Compressive Strength and Permeability of Chemical Sand Control Artificial Cores", the compressive strength of the consolidated cores was tested, and the data results are shown in Table 2.

[0136] Table 1

[0137]

[0138] Table 2

[0139]

[0140]

[0141] Among them, due to the high system viscosity of the phenolic resin sand-fixing agent and the epoxy resin sand-fixing agent, they could not be completely sucked into the 100 - 200 mesh and 150 - 260 mesh formation sands by the vacuum filtration device, resulting in incomplete consolidated cores, completely solidified in the upper part and completely uncemented in the lower part, and the compressive strength could not be tested.

[0142] As can be seen from Table 1 and Table 2, the strength of the core consolidated by the nano-particle sand consolidation material of the present invention is higher than that consolidated by phenolic resin sand consolidant or epoxy resin sand consolidant. Moreover, the permeability of the core consolidated by the nano-particle sand consolidation material of the present invention is higher than that of phenolic resin sand consolidant or epoxy resin sand consolidant. Especially in the silt with a mesh size of 100-200 and fine silt with a mesh size of 150-260, the core consolidated by the nano-particle sand consolidation material also has good permeability.

[0143] Application Example 1

[0144] Taking an oil well as an example, the well depth of this well is 1523-1554 m, the oil layer thickness is 12 m, and the average formation porosity is 27%. This well produces fine silt, and the median grain size of the sand grains is 0.114 mm. The steps for sand control using the nano-particle sand consolidation material are as follows:

[0145] S1: Inject a pre-treatment fluid into the sand-producing layer. Among them, the pre-treatment fluid is clear water + 1% α-olefin sulfonate (AOS) + 2% KCl, and the construction displacement is not less than 1 m 3 / min, and the dosage of the pre-treatment fluid is 10 m 3 ;

[0146] S2: Inject a gel plugging agent into the sand-producing layer. Among them, the gel plugging agent is clear water + 0.6% guar gum powder + 0.2% ammonium persulfate, and the construction displacement is not higher than 1 m 3 / min, and the dosage of the gel plugging agent is 8 m 3 ;

[0147] S3: Inject the sand consolidation material prepared in Example 1 into the sand-producing layer. Use a 700-type pump truck to pump the mixed nano-particle sand consolidation material into the formation. The construction displacement is not higher than 1 m 3 / min, the total dosage of the sand consolidation material is 2.5 m 3 , and the sand consolidation radius is 0.5 m;

[0148] S4: Inject a displacement fluid. Among them, the displacement fluid is clear water, and use the displacement fluid to displace the sand consolidation material to the sand-producing layer;

[0149] S5: After shutting in the well for curing for 12-48 h, open the well for production.

[0150] Before implementing the sand control measures for this well, the average pump inspection period was 112 days, the average liquid production was 4.5 m 3 / d, and the average oil production was 0.8 m 3 / d. After using the sand consolidation material of the present invention for sand control operations, as of July 20, 2022, it has been in normal production for 236 days, with an average liquid production of 6.2 m 3 / d and an average oil production of 1.6 m 3 / d. It shows good sand control effect and plays a certain role in increasing production.

[0151] As can be seen from the above embodiments and comparative examples, when the sand consolidation material containing modified nanoparticles of the present invention is applied to oil and gas wells, on the one hand, by utilizing the adsorption property of the nanoparticles, they automatically adsorb and aggregate on the surface of formation sand; on the other hand, by utilizing the surface activity of the nanoparticles, a very thin nanoparticle aggregation network is formed under the action of the curing agent and formation temperature, playing a role in aggregating, curing and crosslinking sand consolidation.

[0152] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.

Claims

1. A modified nanoparticle for sand control in oil and gas wells, characterized in that, The modified nanoparticles comprise an inorganic nanoparticle core, a coupling agent segment grafted on the surface of the inorganic nanoparticles, and an organic segment grafted on the surface of the inorganic nanoparticles and / or the coupling agent segment; wherein, based on the weight of the inorganic nanoparticles, the content of the coupling agent segment is 0.1-0.8 wt%, and the content of the organic segment is 30-70 wt%.

2. The modified nanoparticle according to claim 1, wherein, Based on the weight of the inorganic nanoparticles, the content of the organic segment is 45-60 wt%; Preferably, the substance providing the organic segment is a small molecule organic compound with a molecular weight ≤500 g / mol.

3. The modified nanoparticle according to claim 1 or 2, wherein, The small molecule organic compound is selected from one or more of 4-vinylcyclohexene oxide, allyl polyoxyalkylene epoxy ether, cyclohexyltrimethylsilane, epoxy cage-like silsesquioxane, methyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, phenyltrimethoxysilane; more preferably 4-vinylcyclohexene oxide and / or allyl polyoxyalkylene epoxy ether.

4. The modified nanoparticle according to any one of claims 1-3, wherein, The substance providing the coupling agent segment is a silane coupling agent.

5. The modified nanoparticle according to claim 4, wherein, The silane coupling agent is selected from one or more of aminopropyltriethoxysilane, methyltriethoxysiloxane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

6. The modified nanoparticle according to any one of claims 1-5, wherein, The average particle size of the inorganic nanoparticles is 10-100 nm; and / or, the inorganic nanoparticles are selected from one or more of nano-silica, nano-carbon fiber, carbon nanotube, nano-titanium oxide, nano-aluminum oxide.

7. The modified nanoparticle according to any one of claims 1-6, wherein, The average particle size of the modified nanoparticles ≤1000 nm.

8. A sand consolidation material, characterized in that, The sand consolidation material comprises component A, component B and component C; wherein, the component A is the modified nanoparticles described in any one of claims 1-7.

9. The sand consolidation material according to claim 8, wherein, The component B is selected from curing agents; Preferably, the component B is a water-soluble epoxy resin.

10. The sand consolidation material according to claim 8 or 9, wherein, The component B comprises polyetheramine and methanol; Preferably, in the component B, the weight ratio of polyetheramine to methanol is 100:(5-20).

11. The sand consolidation material according to any one of claims 8-10, wherein, The component C is selected from clay anti-swelling agents.

12. The sand consolidation material according to any one of claims 8-11, wherein, The component C is selected from one or more of KCl, organic quaternary ammonium salts, organic cationic polymers.

13. The sand consolidation material according to any one of claims 8-12, wherein, In the sand consolidation material, the weight ratio of component A, component B, and component C is 1:(0.2-1):(1-10); preferably 1:(0.2-0.5):(2-6).

14. The sand consolidation material according to any one of claims 8-13, wherein, The viscosity of the sand consolidation material at 20-90 °C is 10-30 mPa·s; and / or, the sand consolidation strength of the sand consolidation material ≥8 MPa; and / or, the sand consolidation permeability of the sand consolidation material ≥2 μm.

15. Application of the sand consolidation material according to any one of claims 8-14 in oil and gas reservoir development.

16. An oil and gas well sand control method, characterized in that, The method comprises: (1) Injecting the sand consolidation material into the sand-producing formation of the oil and gas well; (2) Then injecting a displacement fluid into the sand-producing formation; wherein, the sand consolidation material is the sand consolidation material described in any one of claims 8-14.

17. According to the method of claim 16, wherein, The method further comprises: before step (1), injecting a profile control and plugging agent into the sand-producing formation.

18. According to the method of claim 17, wherein, The profile control and plugging agent comprises a high molecular weight viscosifier and a gel breaker; Preferably, based on the total weight of the profile control and plugging agent, the addition amount of the high molecular weight viscosifier is 0.2-0.8 wt%, and the addition amount of the gel breaker is 0.1-0.3 wt%.

19. According to the method of claim 17 or 18, wherein, The method further includes: before injecting the plugging agent into the sand-producing formation, treating the sand-producing formation with a treating fluid.

20. According to the method of claim 19, wherein, The treating fluid contains a deoiling agent and a swelling inhibitor; Preferably, based on the total weight of the treating fluid, the addition amount of the deoiling agent is 0.5 - 5 wt%, and the addition amount of the swelling inhibitor is 2 - 4 wt%.

21. According to the method of any one of claims 16-20, wherein, The method further includes: shutting in the well for curing after step (2); Preferably, the temperature for the well shut-in curing is 50 - 90 °C, and the time is 12 - 48 h.

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