CN112457835A

CN112457835A - High-temperature-resistant salt-resistant composite plugging agent

Info

Publication number: CN112457835A
Application number: CN202011335729.6A
Authority: CN
Inventors: 李成勇; 冯青; 彭立
Original assignee: Chengdu Univeristy of Technology
Current assignee: Chengdu Univeristy of Technology
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2021-03-09
Anticipated expiration: 2040-11-25
Also published as: CN112457835B

Abstract

The invention relates to a composite plugging agent, which consists of the following components in percentage by mass: 20-30% of phenolic aldehyde prepolymer, 20-30% of sodium organosilicate, 1-5% of cross-linking agent, 10-15% of beta-cyclodextrin polymer, 5-15% of active siloxane, 2.5-5% of sodium polyphosphate, 1-5% of stabilizing agent and the balance of water. According to the invention, organic silicon compounds a plurality of high-temperature resistant organic materials and inorganic materials to form a reticular polymer with a porous spongy skeleton structure, so that the toughness and compactness of the inorganic material are improved, the swelling resistance and temperature resistance of the organic material are improved, and a novel high-temperature resistant gel is formed.

Description

High-temperature-resistant salt-resistant composite plugging agent

Technical Field

The invention belongs to the technical field of tertiary oil recovery, and relates to a high-temperature-resistant salt-resistant composite plugging agent.

Background

In the process of oil exploitation, most oil wells are developed by water injection, particularly high-speed high-liquid-volume exploitation of offshore oil fields, because of the influence of reservoir heterogeneity, water injection forms a dominant channel, or ineffective circulation is formed in cracks and large channels, the recovery ratio cannot be further improved, if the exploitation effect is improved, the plane and longitudinal contradiction of an oil reservoir need to be adjusted and controlled, and the profile control agent can force the liquid flow to turn by plugging the large channels, so that the water drive wave and the volume are enlarged, and the purpose of stable yield and high yield of the oil fields is achieved.

Aiming at high-temperature (more than 90 ℃) and high-salinity (more than 10 ten thousand mg/l) oil reservoirs, the conventional profile control agent has unsatisfactory effect and large on-site implementation risk. The main body of the high-temperature resistant organic plugging agent such as emulsion polymer gel and AMPS copolymer gel adopted in oil fields at present is a polymer derivative, and the high-temperature resistant organic plugging agent has the advantages of online continuous deep injection and the disadvantages of easy increase of hydrolysis degree, excessive crosslinking, long-chain fracture, poor adsorption performance, serious shearing damage, low curing degree, limited temperature resistance and salt resistance, limited pressure bearing capacity and the like of the polymer derivative under a high-temperature condition. The high-temperature resistant inorganic plugging agent such as water glass, superfine cement and the like is high-temperature resistant and high-salt resistant, and has the defects of easy pressure rise, large hardness, poor toughness and frangibility, large volume dehydration shrinkage amplitude, short injection distance, high construction risk and incapability of realizing deep plugging adjustment. In land oil fields, high-temperature resistant resin is tried to be added into high-temperature resistant inorganic material cement and water glass, the problems of high temperature resistance, plugging strength and injectability are expected to be solved, in fact, different plugging agents are compounded and injected, the difference of the propelling speed is easy to separate water, the injection control difficulty is large, and the phenomena of gelling and plugging or non-gelling and plugging are often caused on site.

Disclosure of Invention

The invention aims to solve the technical problem of providing a high-temperature-resistant salt-resistant composite plugging agent to achieve the purposes of oil stabilization, water control and development effect improvement in oil fields.

The technical scheme for realizing the purpose of the invention is as follows:

the composite plugging agent comprises the following components in percentage by mass: 20-30% of phenolic aldehyde prepolymer, 20-30% of sodium organosilicate, 1-5% of cross-linking agent, 10-15% of beta-cyclodextrin polymer, 5-15% of active siloxane, 2.5-5% of sodium polyphosphate, 1-5% of stabilizing agent and the balance of water.

And the preparation method of the phenolic aldehyde prepolymer comprises the steps of sucking phenol and formaldehyde with the molar ratio of 2.5: 1-3: 1 into a reaction kettle in batches by a vacuum pump under the action of an alkaline catalyst, and reacting for 4-5 hours at the temperature of 50-60 ℃, wherein the content of hydroxymethyl in the phenolic aldehyde prepolymer is 18.92-23.34%.

In addition, the cross-linking agent is calculated by 100 percent, the mass percent of ammonium bicarbonate is 10 to 20 percent, the mass percent of organic chromium is 20 to 30 percent, and the balance is epoxy resin.

Preferably, the cross-linking agent is a mixture of 10% by mass of ammonium bicarbonate, 30% by mass of organic chromium and 60% by mass of epoxy resin, based on 100%. The three are mixed according to the proportion, the coordination effect among different monomers can be exerted, and the gelling performance under the conditions of high temperature and high mineralization degree is improved.

Moreover, the beta-cyclodextrin polymer is a reaction mixed product obtained by stirring hydroxypropyl distarch phosphate, beta-cyclodextrin cassava starch and melamine in a molar ratio of 2:6:2 at the temperature of 50-60 ℃ for about 1-2 hours, and can integrally improve the tackifying effect and long-term thermal stability of the phenolic aldehyde prepolymer under the high-temperature condition.

And the active siloxane is a mixture of primary amino modified organic silicone oil KF-865 and aminoethyl tripropoxysilane according to the molar ratio of 1:1, and the two are mixed according to the proportion, so that the effect of the siloxane coupling phenolic aldehyde prepolymer and the sodium organosilicate is improved, and the effect is better in the aspect of increasing the stability of the composite plugging agent than the effect of mixing according to other proportions.

And the sodium polyphosphate is sodium tripolyphosphate, and the uniform dispersion degree and viscoelasticity of the composite plugging agent can be improved by controlling the concentration range.

And the stabilizer is a mixture of at least two of sodium ethyl sulfamate, ammonium hydroxide, polyvinyl alcohol, furfural and sodium phosphate.

Preferably, the stabilizer is a mixture of sodium slow ethyl sulfamate and ammonium hydroxide, the mass percentage of the sodium slow ethyl sulfamate is 30-40% and the balance is ammonium hydroxide, wherein the heat stabilizer accounts for 100%. The stabilizer can effectively control the reaction speed, slow down the reaction heat release and improve the product quality, and if the reaction speed is violent, the resin molecular weight can be greatly different, the free phenol content is high, and the resin quality is reduced.

Preferably, the composite plugging agent consists of the following components in percentage by mass: 25% of phenolic aldehyde prepolymer, 25% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 5% of cross-linking agent, 10% of active siloxane, 2.5% of sodium polyphosphate, 5% of stabilizing agent and the balance of deionized water.

A preparation method of a composite plugging agent comprises the steps of sequentially adding organic sodium silicate, a modified phenolic prepolymer, active siloxane, a beta-cyclodextrin polymer and sodium polyphosphate into a stirring reactor, stirring for 2 hours, uniformly mixing to form an amphiphilic inclusion system, and then adding a stabilizer and a cross-linking agent to form a gel profile control agent. The siloxane is coupled with the phenolic aldehyde prepolymer and the organic sodium silicate to form the high-molecular composite plugging agent, so that the integrity of the product in the injection process is effectively ensured, and then the stabilizer and the cross-linking agent are added to strengthen the temperature resistance, salt tolerance and plugging performance of the composite plugging agent.

The specific stirring speed and time can be reasonably set according to actual conditions, in a preferred embodiment, the stirring speed is 500-1000 r/min, the coupling reaction temperature is 40-100 ℃, considering that the pH value can influence the reaction polymerization crosslinking time in the process of adding the stabilizer and the crosslinking agent, and in order to regulate and control the polymerization crosslinking speed, the pH value of the composite plugging agent solution is preferably controlled to be 5-9.

The first aspect of the invention provides a preparation method of high-temperature-resistant high-salt inclusion gel, namely a preparation idea of coupling first and then crosslinking, which mainly comprises the following steps: dispersing organic sodium silicate, a beta-cyclodextrin polymer and a phenolic aldehyde prepolymer in a sodium polyphosphate solution, and then performing inclusion by using water-soluble siloxane oil to form a composite tackifying system with good flowing property, wherein the initial apparent viscosity is 20-150 mPa.s, and the composite tackifying system can be used as an oil displacement agent under the conditions of high temperature and high salt; adding a cross-linking agent and a stabilizing agent into the tackifying system, and uniformly mixing to obtain the slowly cross-linked two-way inclusion gel deep profile control and flooding agent, wherein the gel viscosity reaches more than 50000 mPa.s.

The second aspect of the invention provides an inclusion gel profile control agent prepared by any one of the methods, the gelling strength is greater than 50000mPa.s, the gel profile control agent can resist the temperature of more than 350 ℃ after gelling, the salt tolerance is greater than 20 ten thousand mg/l, and the profile control agent can be applied to profile control and flooding of high-temperature and high-salt oil reservoirs.

In order to solve the problem that the conventional plugging agent is not resistant to high temperature and has poor profile control and flooding effects under high salt oil reservoir conditions, organic siloxane (covalent bonds with 50% ionic bond characteristics, directional covalent bonds and nondirectional ionic bonds) which is compatible with organic materials and inorganic materials is provided, a host-guest inclusion polymer system is formed by silicone gel and a modified phenolic aldehyde prepolymer through hydrophobic action and van der waals force, and the system has good injectability, outstanding temperature and salt resistance and 20-150 mPa.s of initial bulk viscosity and can be used as an oil displacement agent under high temperature and high salt conditions, because the bond energy of the Si-O bonds of the organic siloxane is 121 kilocalories/gram molecule and is higher than the bond energy of the C-C bonds of 82.6 kilocalories/gram molecule, and has low surface tension, wettability and stable physiological inertia.

A certain amount of cross-linking agent and stabilizing agent are added according to actual needs to form inclusion gel, the viscosity of the gel reaches more than 50000mPa & s, the gel can be used as a profile control agent under the conditions of high temperature and high salt, the gel improves the toughness and compactness of the original inorganic material plugging agent, improves the swelling resistance and temperature resistance of the organic material plugging agent, and has great application prospect in the aspect of high-temperature and high-salt oil reservoir development.

The invention has the advantages and beneficial effects that:

1. the invention adopts organic siloxane to compound two high temperature resistant plugging agents, namely organic phenolic resin and inorganic silicic acid gel, which are commonly used in oil fields into a new gel system, and after different plugging agents, such as phenolic resin and silicic acid gel, are compounded, the phenomenon of delamination often occurs, as shown in figure 2a, the injection process can not enter an ideal position, and even the plugging or the plugging can not be realized. The gel system has no layering phenomenon, as shown in figure 2b, the injectability is superior to simple mixing of two plugging agents, the system has strong plugging capability, the residual resistance coefficient (representing the capability of the plugging agent for reducing the permeability of a reservoir) is 18-46 and is higher than the residual resistance coefficient (less than 10) of the conventional temperature-resistant plugging agent after the water glass or phenolic resin is gelled, the system can be configured by seawater, high salinity saline water (25 ten thousand ppm) and produced sewage after appropriate oil-water separation treatment, and the preparation cost of chemical agents is reduced; the gel profile control agent has strong thermal stability (stable performance after being aged for 360 days at 130 ℃), simple preparation method, controllable crosslinking time of the gel profile control agent, strong practicability and convenient popularization, and can be used in high-temperature and high-salinity reservoir stratum.

2. According to the invention, two high-temperature resistant organic materials and an inorganic material are compounded together through organic silicon to form a reticular polymer with a porous spongy framework structure, so that the toughness and compactness of the inorganic material are improved, the swelling resistance and temperature resistance of the organic material are improved, and a novel high-temperature resistant gel is formed.

3. The surface tension of the profile control and flooding agent is between 32 and 46mN/m and lower than the surface tension of 75.49mN/m of crude oil, the injection process is generally not pressurized, the problem that the conventional plugging agent is difficult to coordinate between profile control and flooding depth and profile control and flooding strength is solved,

4. the gel has the preservation validity period of more than 6 months at room temperature, the gelling time of 24-120 h, the temperature resistance of more than 350 ℃, the salt tolerance of more than 20 ten thousand mg/l, the gel viscosity of more than 50000mPa & s,

5. the invention belongs to the range of tertiary oil recovery, is suitable for deep profile control and flooding operation treatment of an injection well, and has good application prospect in the aspect of improving the crude oil recovery ratio in the later development of a high water-cut oil field.

Drawings

Fig. 1 is an SEM image (300 times) of the composite plugging agent of the present invention.

FIG. 2a is a diagram showing a state after mixing of a resin and water glass;

fig. 2b is a diagram of a blocking agent of the present invention.

Detailed Description

The technical solutions will be described clearly and completely in the following with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and all other embodiments obtained by those skilled in the art without any creative work belong to the protection scope of the present invention.

Example 1

A high-temperature-resistant salt-resistant composite plugging agent comprises the following components in percentage by mass:

25% of phenolic aldehyde prepolymer, 25% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 5% of cross-linking agent, 10% of active siloxane, 2.5% of sodium polyphosphate, 5% of stabilizer and a proper amount of deionized water.

Sequentially adding organic sodium silicate, phenolic aldehyde prepolymer, active siloxane, beta-cyclodextrin polymer and sodium polyphosphate into a stirring reactor, stirring for 2 hours, uniformly mixing to form an amphiphilic inclusion system, and adding a stabilizer and a cross-linking agent to form a gel profile control and flooding agent.

The preparation method of the phenolic aldehyde prepolymer is characterized in that under the action of an alkaline catalyst, phenol and formaldehyde with the molar ratio of 2.5: 1-3: 1 are sucked into a reaction kettle in batches by a vacuum pump and react for about 4-5 hours at the temperature of 50-60 ℃, and the content of hydroxymethyl in the phenolic aldehyde prepolymer is 18.92-23.34%.

The cross-linking agent is a mixture of 10 percent by mass of ammonium bicarbonate, 30 percent by mass of organic chromium and 60 percent by mass of epoxy resin in 100 percent.

The beta-cyclodextrin polymer is a mixed product of hydroxypropyl distarch phosphate, beta-cyclodextrin cassava starch and melamine with the molar ratio of 2:6:2, which are stirred for about 1-2 hours at the temperature of 50-60 ℃ and react.

The active siloxane is a mixture of primary amino modified organic silicone oil KF-865 and aminoethyl tripropoxysilane according to the molar ratio of 1: 1.

The sodium polyphosphate is sodium tripolyphosphate.

The stabilizer is a mixture of sodium slow ethyl sulfamate and ammonium hydroxide, the mass percent of the sodium slow ethyl sulfamate is 30-40%, and the balance is the ammonium hydroxide.

According to the method, the raw materials and the proportions of the components are utilized, and the mixing reaction is carried out according to the operation, so that the composite plugging agent with good compressive strength, temperature resistance and salt tolerance is obtained.

The plugging agent stock solution of the example is diluted to 5% concentration by clear water according to SY/T5590-2004 profile control agent performance evaluation method, gelling time and gelling strength tests are carried out, and data such as the highest temperature, mineralization degree, gelling time, initial viscosity, gelling viscosity and the like of gelling are recorded. The viscosity, measured at a test temperature of 130 ℃, a degree of mineralization of 180000mg/L and a PH of 7, is greater than 40000mpa.s, the test results being given in table 1.

Example 2

The difference from example 1 is that: the components by mass percentage are as follows:

15% of phenolic aldehyde prepolymer, 15% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 2.5% of cross-linking agent, 10% of active siloxane, 2.5% of sodium polyphosphate, 5% of stabilizing agent and a proper amount of deionized water. The test results are shown in Table 1.

Example 3

15% of phenolic aldehyde prepolymer, 15% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 2.5% of cross-linking agent, 10% of active siloxane, 2.5% of sodium polyphosphate, 2.5% of stabilizing agent and a proper amount of deionized water. The test results are shown in Table 1.

Example 4

25% of phenolic aldehyde prepolymer, 25% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 5% of cross-linking agent, 5% of active siloxane, 2.5% of sodium polyphosphate, 5% of stabilizer and a proper amount of deionized water. The test results are shown in Table 1.

Comparative example 1

The differences from example 1 are: the reactive silicone was not added, and the remaining components were the same as in example 1. The test results are shown in Table 1.

Comparative example 2

The differences from example 1 are: the other components were the same as in example 1 without adding a crosslinking agent and a stabilizer. The test results are shown in Table 1.

TABLE 1 evaluation of the temperature and salt resistant composite blocking agent (5% concentration)

It can be seen from the table that the main agent of the composite plugging agent is the phenolic prepolymer and the sodium organosilicate of the common high-temperature and high-salt resistant plugging agent, and when the active siloxane is between 10% and 15%, the composite plugging agent has good compressive strength and migration performance under the conditions of the test temperature of 130 ℃, the mineralization degree of 180000mg/L and the pH value of 7.

According to the invention, two materials with different properties, namely an organic material and an inorganic material, are coupled firstly, and a preparation idea of post-crosslinking polymerization is taken as a guide, and a good temperature-resistant and salt-resistant plugging agent for profile control and flooding of a water injection well is obtained by preferably selecting the components and the proportion of a temperature-resistant and salt-resistant high-molecular functional monomer, a stabilizer, a crosslinking agent and a dispersing agent, and has the advantages of simple preparation, no need of special nitrogen removal and oxygen removal and the like.

The profile control agent has the advantages of high compressive strength, controllable gelling time, good temperature resistance and salt resistance, low surface tension, certain emulsification and oil washing capacities and certain viscoelasticity, and can meet the requirement of high-dose deep injection in a small pressure space range in the injection process.

The method is suitable for profile control and flooding plugging of a high-porosity and high-permeability channel caused by heterogeneity in the process of conglomerate reservoir exploitation, meets the requirement of further improving the recovery ratio of oil fields with the reservoir temperature below 150 ℃ and the mineralization degree below 200000mg/l at home and abroad, and develops 12-well profile control and flooding in 2019 when the conventional high-temperature profile control agent is used in the stage of indoor experiments and the technology is immature, so that the average oil increase of a single well is 500 tons, and the profile control and flooding effect is obvious.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept, and these changes and modifications are all within the scope of the present invention.

Claims

1. The composite plugging agent comprises the following components in percentage by mass:

20-30% of phenolic aldehyde prepolymer,

20-30% of organic sodium silicate,

1-5% of cross-linking agent,

10-15% of beta-cyclodextrin polymer,

5-15% of active siloxane,

2.5 to 5 percent of sodium polyphosphate,

1-5% of stabilizer,

The balance being water.

2. The composite plugging agent according to claim 1, wherein: the preparation method of the phenolic aldehyde prepolymer is characterized in that under the action of an alkaline catalyst, phenol and formaldehyde in a molar ratio of 2.5: 1-3: 1 react for about 4-5 hours at the temperature of 50-60 ℃, and the content of hydroxymethyl in the phenolic aldehyde prepolymer is 18.92-23.34%.

3. The composite plugging agent according to claim 1, wherein: the cross-linking agent is calculated by 100 percent, the mass percent of ammonium bicarbonate is 10 to 20 percent, the mass percent of organic chromium is 20 to 30 percent, and the balance is epoxy resin.

4. The composite plugging agent according to claim 1, wherein: the beta-cyclodextrin polymer is a product obtained by stirring hydroxypropyl distarch phosphate, beta-cyclodextrin tapioca starch and melamine in a molar ratio of 2:6:2 at 50-60 ℃ for 1-2 hours to react.

5. The composite plugging agent according to claim 1, wherein: the active siloxane is a mixture of primary amino modified organic silicone oil KF-865 and aminoethyl tripropoxysilane according to the molar ratio of 1: 1.

6. The composite plugging agent according to claim 1, wherein: the sodium polyphosphate is sodium tripolyphosphate.

7. The composite plugging agent according to claim 1, wherein: the stabilizer is a mixture of at least two of sodium ethyl sulfamate, ammonium hydroxide, polyvinyl alcohol, furfural and sodium phosphate.

8. The composite plugging agent according to claim 7, wherein: the stabilizer is a mixture of sodium slow ethyl sulfamate and ammonium hydroxide, the mass percent of the sodium slow ethyl sulfamate is 30-40%, and the balance is the ammonium hydroxide.

9. The composite plugging agent according to claim 1, wherein: the composite material comprises the following components in percentage by mass: 25% of phenolic aldehyde prepolymer, 25% of sodium organosilicate, 10% of beta-cyclodextrin polymer, 5% of cross-linking agent, 10% of active siloxane, 2.5% of sodium polyphosphate, 5% of stabilizing agent and the balance of deionized water.

10. The method for preparing the composite plugging agent according to claim 1, wherein the method comprises the following steps: sequentially adding organic sodium silicate, phenolic aldehyde prepolymer, active siloxane, beta-cyclodextrin polymer and sodium polyphosphate into a stirring reactor, stirring and mixing uniformly to form an amphiphilic inclusion system, wherein the amphiphilic inclusion system can be used as a composite oil displacement agent under the condition of high temperature and high salt, and a stabilizing agent and a cross-linking agent are added to form a gel profile control and flooding agent and can be used as a composite profile control and plugging agent under the condition of high temperature and high salt.