阅读说明：本技术 一种耐温泡沫凝胶及其制备方法与应用 (Temperature-resistant foam gel and preparation method and application thereof ) 是由 林梅钦 杨子浩 罗智忆 董朝霞 李晓晨 于 2019-11-25 设计创作，主要内容包括：本发明公开了一种耐温泡沫凝胶及其制备方法与应用。按照质量百分比计,泡沫凝胶包括如下组分：聚合物0.3％；交联剂0.15～0.35％；起泡剂0.05～0.15％；余量的水；交联剂为交联剂A或交联剂A与交联剂B的混合物,交联剂A为间苯二酚；交联剂B为甲醛。使用显微镜和扫描电镜观察水基泡沫、聚合物溶液泡沫和泡沫凝胶的微观结构,由结果得知,普通泡沫和聚合物在常温条件下由于液膜的流动无法保持长时间的稳定,泡沫凝胶的液膜形成了网状凝胶结构,从而增强了液膜的黏度和强度,阻碍了液膜的流动,泡沫凝胶在高温条件下具有较好的稳定性。通过低渗裂缝型岩心封堵实验,本发明泡沫凝胶体系可以在岩心中形成有效封堵,抑制气体突破效果良好,在低渗油藏中具有广阔的应用前景。(The invention discloses a temperature-resistant foam gel and a preparation method and application thereof. The foam gel comprises the following components in percentage by mass: 0.3% of a polymer; 0.15-0.35% of a cross-linking agent; 0.05-0.15% of foaming agent; the balance of water; the cross-linking agent is a cross-linking agent A or a mixture of the cross-linking agent A and a cross-linking agent B, and the cross-linking agent A is resorcinol; the crosslinking agent B is formaldehyde. The microscopic structures of the water-based foam, the polymer solution foam and the foam gel are observed by using a microscope and a scanning electron microscope, and the results show that the common foam and the polymer can not keep stable for a long time due to the flowing of the liquid film under the normal temperature condition, and the liquid film of the foam gel forms a reticular gel structure, so that the viscosity and the strength of the liquid film are enhanced, the flowing of the liquid film is hindered, and the foam gel has better stability under the high temperature condition. Through a low-permeability fractured core plugging experiment, the foam gel system can form effective plugging in the core, has a good effect of inhibiting gas breakthrough, and has a wide application prospect in a low-permeability reservoir.)

1. The foam gel comprises the following components in percentage by mass:

0.3% of a polymer;

0.15-0.35% of a cross-linking agent;

0.05-0.15% of foaming agent;

the balance of water;

the cross-linking agent is a cross-linking agent A or a mixture of the cross-linking agent A and a cross-linking agent B, and the cross-linking agent A is resorcinol; the cross-linking agent B is formaldehyde;

the foaming agent is cocamidopropyl betaine, sodium dodecyl sulfate or sodium dodecyl benzene sulfonate.

2. The foam gel of claim 1, wherein: the polymer is polyacrylamide, and the molecular weight of the polymer is 2000-2800 ten thousand.

3. The foam gel of claim 1 or 2, wherein: when the cross-linking agent is a mixture of the cross-linking agent A and the cross-linking agent B, the mass percentage of the cross-linking agent A is 0.15-0.30%;

the mass percentage of the cross-linking agent B is 0.02-0.04%.

4. The foamed gel of claim 3, wherein: in the foamed gel, the mass percentage of the cross-linking agent A is 0.245%;

the mass percentage of the cross-linking agent B is 0.035%.

5. The foam gel of claim 1 or 2, wherein: when the cross-linking agent is the cross-linking agent A, the mass percentage of the cross-linking agent A is 0.15-0.30%.

6. The foamed gel of claim 5, wherein: in the foamed gel, the mass percentage of the cross-linking agent A is 0.26%.

7. The foam gel of any one of claims 1 to 6, wherein: the foaming agent is cocamidopropyl betaine;

the foaming agent accounts for 0.075 percent by mass.

8. The foam gel of any one of claims 1 to 7, wherein: the foam gel further comprises a foam stabilizer;

the foam stabilizer is xanthan gum;

the mass percentage content of the foam stabilizer is 3%;

the foamed gel further comprises an oxygen scavenger;

the oxygen scavenger is thiourea;

the mass percentage of the oxygen scavenger is 0.4%.

9. A process for the preparation of a foam gel as claimed in any one of claims 1 to 8, comprising the steps of:

preparing an aqueous solution of the polymer, sequentially adding the components 1) or 2) to the aqueous solution, and stirring and foaming the aqueous solution to obtain the polymer;

1) the compound cross-linking agent and the foaming agent;

2) the compound cross-linking agent, the foaming agent, the foam stabilizer and the oxygen scavenger.

10. Use of the foam gel of any one of claims 1-8 as a profile control agent for or in a profile control of a hypotonic reservoir.

Technical Field

The invention relates to a temperature-resistant foam gel and a preparation method and application thereof, belonging to the technical field of optimizing gas flooding and volume.

Background

In recent years, the rapid development of the economy of China improves the urbanization level and accelerates the industrialization process. Many high and new technology industries such as a series of modern industries of refining, fine chemistry, aerospace and the like require a large amount of petroleum as a raw material and industrial production energy. The chemical products such as diesel oil, gasoline, asphalt, paraffin wax and the like refined from petroleum are widely applied to daily life and production of people. Therefore, oil consumption has been increasing and has been high for many years. With the large-scale exploitation and development of oil fields, petroleum as a non-renewable energy source has gradually entered the decline period, and the demand for new techniques for oil well productivity development and oil recovery has become increasingly urgent. The tertiary oil recovery technology changes the current oil recovery mode, deeply excavates the potential of the low-yield well, exerts the maximum energy of the low-yield well and ensures the recovery quality of the old oil field.

On the basis of a foam water plugging system and a gel water plugging system, a foam gel water plugging system is further developed. The foamed gel system is a composite system formed by foaming and then crosslinking polymer solution to form gel. The system has the characteristics of water-based foam before gelling and weak gel after gelling, the main difference between the foam gel and the water-based foam is that the continuous phases of the foam gel are different, and the foam gel is foam taking gel as an external phase, so that the foam gel system has good mechanical strength and stability, and the water plugging effective period of the foam gel system can be prolonged.

With the continuous and deep development of petroleum, the foam gel performance requirement of increasingly complex reservoir environments is higher and higher. The development work of the temperature-resistant foamed gel system in China has been greatly advanced, and the experiment in the mine field has also been rich in experience. However, most of the temperature-resistant gel foam systems developed at present have poor stability, and the foam gel is easy to break under the high-temperature condition, so that the stratum cannot be plugged for a long time. Therefore, it is required to provide a high temperature resistant and high stability foam gel system.

Disclosure of Invention

The invention aims to provide a temperature-resistant foam gel, wherein a Haake rheometer and a Brookfield viscometer are used for researching rheological property and stability of a foam gel system and influencing factors of the foam gel system, and a scanning electron microscope is used for observing the microstructure of the foam gel system to obtain the foam gel system with high temperature resistance and high stability.

The temperature-resistant foamed gel provided by the invention comprises the following components in percentage by mass:

0.3% of a polymer;

0.15-0.35% of a cross-linking agent;

0.05-0.15% of foaming agent;

the balance of water;

the cross-linking agent is a cross-linking agent A or a mixture of the cross-linking agent A and a cross-linking agent B, and the cross-linking agent A is resorcinol; the cross-linking agent B is formaldehyde;

the foaming agent is cocamidopropyl betaine (CAB-35), Sodium Dodecyl Sulfate (SDS) or Sodium Dodecyl Benzene Sulfonate (SDBS), and three surfactants of CAB-35, SDS and SDBS have good compatibility with gel systems of the cross-linking agent A and the cross-linking agent B, and have good temperature resistance.

Tests on the foaming capacity and the foam stabilizing capacity of the foaming agent show that the CAB-35 has the highest foam comprehensive value and the polymer foam has the best stability, and the CAB-35 with the dosage of 0.075 wt% is selected as the foaming agent of the foam gel system in consideration of comprehensive compatibility, temperature resistance, foaming and foam stabilizing capacity, so that the generation and the stability of the foam gel system are facilitated.

In the temperature-resistant foamed gel, the polymer can be polyacrylamide, and the molecular weight of the polymer is 2000-3000 ten thousand;

specifically, the polyacrylamide KYPAM (Beijing chemostat chemical company Limited) has the molecular weight of 2500-2800 ten thousand.

In the foamed gel, when the cross-linking agent is the mixture, the mass percentage of the cross-linking agent A is 0.15-0.30%, and the preferable mass percentage is 0.245%;

the mass percentage content of the cross-linking agent B is 0.02-0.04%, and the preferable mass percentage content is 0.035%.

In the foamed gel, when the cross-linking agent is the cross-linking agent A, the mass percentage of the cross-linking agent A is 0.15-0.30%, and the preferable mass percentage is 0.26%.

The cross-linking agent A and the compound cross-linking agent (the mixture of the cross-linking agent A and the cross-linking agent B) adopted by the invention have the capability of quick cross-linking, and can form a liquid film with certain strength, so that better foam gel can be formed by cross-linking in the foam half-life period.

In the temperature-resistant foam gel, the foam gel further comprises a foam stabilizer;

the foam stabilizer can be xanthan gum, and the molecular weight of the foam stabilizer is 200-600 ten thousand, such as 300 ten thousand;

the mass percentage of the foam stabilizer can be 3%.

The foam stabilizer prolongs the half-life period of the foam, so that the polymer has longer time to crosslink with the crosslinking agent, and a gel-phase liquid film with higher viscosity is formed by crosslinking when the liquid film has larger thickness, thereby improving the stability of the foam gel and enabling the foam gel to be stable for a longer time under a high-temperature condition; however, excessive foam stabilizer reacts with the cross-linking agent to form flocculent precipitate, which is discharged to the bottom of the measuring cylinder along with the precipitation solution, so that the strength of the foamed gel is slightly reduced, which is not beneficial to the formation and stabilization of the foamed gel, and therefore, the optimal dosage of the foam stabilizer is 3%.

In the temperature-resistant foam gel, the foam gel further comprises an oxygen scavenger;

the oxygen scavenger may be thiourea;

the mass percentage of the oxygen scavenger can be 0.4%.

With the increase of the concentration of the oxygen scavenger, the precipitation of the foamed gel is gradually reduced, so that more polymer solutions are crosslinked to form a gel-phase liquid film, the strength of the foamed gel is enhanced, and the excessive oxygen scavenger does not have adverse effect on the formation of the foamed gel. Comprehensively, the optimal dosage of the oxygen scavenger is 0.4 wt%.

Under the condition of 80 ℃ and 10000mg/L NaCl mineralization degree, the viscosity of the foam gel of the invention reaches about 12000 mPa.s, and the stable foam gel can be formed.

Under the condition of 100 ℃ and 10000mg/L NaCl mineralization degree, the temperature-resistant foam gel has good stability, the half-life period can reach 10 days, and the system shows good temperature resistance.

The foamed gel of the present invention can be prepared as follows:

preparing an aqueous solution of the polymer, sequentially adding the following components 1) or 2), and stirring for foaming;

1) the compound cross-linking agent and the foaming agent;

2) the compound cross-linking agent, the foaming agent, the foam stabilizer and the oxygen scavenger.

The microscopic structures of the water-based foam, the polymer solution foam and the foam gel are observed by using a microscope and a scanning electron microscope, and the results show that the common foam and the polymer can not keep stable for a long time due to the flowing of the liquid film under the normal temperature condition, and the liquid film of the foam gel forms a reticular gel structure, so that the viscosity and the strength of the liquid film are enhanced, the flowing of the liquid film is hindered, and the foam gel has better stability under the high temperature condition. Through a low-permeability fractured core plugging experiment, the foam gel system can form effective plugging in the core, has a good effect of inhibiting gas breakthrough, and has a wide application prospect in a low-permeability reservoir.

Drawings

FIG. 1 shows the evaluation results of the temperature resistance of the blowing agent.

FIG. 2 is a graph showing the foaming capacity of different foaming agents in an aqueous solution at room temperature.

FIG. 3 is a graph of the foaming capacity of different blowing agents in a 0.3% polymer solution at 80 ℃.

FIG. 4 is a photograph of a foam gel formed with six different cross-linking agents, wherein FIG. 4(a) is a phenolic resin system foam gel and FIG. 4(b) is a cross-linking agent A-phenolic resin system foam gel; FIG. 4(c) is a crosslinker A system foam gel; FIG. 4(d) is a complex crosslinker I system foam gel; FIG. 4(e) is a formulated crosslinker II system foam gel; FIG. 4(f) is a crosslinker B system foam gel.

FIG. 5 shows the amount of cross-linking agent A used and the gel viscosity at different temperatures.

FIG. 6 is a graph of viscosity as a function of shear time for six gel systems after 24 hours.

FIG. 7 is a graph of viscosity versus time for two gel systems.

FIG. 8 shows the amount of liquid separated from two gel foams heated for one week.

FIG. 9 shows two foams for one week, wherein FIG. 9(a) shows a crosslinker A foam gel system and FIG. 9(b) shows a built crosslinker II foam gel system.

FIG. 10 shows the amount of run out of the frothy gel as a function of the amount of foam stabilizer.

FIG. 11 is a graph showing the change in foam viscosity and amount of eluent with oxygen scavenger concentration.

FIG. 12 is a graph of foam gel viscosity as a function of temperature.

FIG. 13 is a graph of gel foam volume as a function of temperature.

FIG. 14 shows the change of the viscosity of the gel foam and the amount of the eluent with temperature.

Fig. 15 shows the microstructure of the water-based foam (fig. 15(a)), the polymer foam (fig. 15(b)), and the foam gel (fig. 15 (c)).

FIG. 16 is a photomicrograph of a water-based foam/gel foam showing the water-based foam after 0min at 25 ℃, FIG. 16(a) is a water-based foam left standing at 25 ℃ for 20min, FIG. 16(c) is a foam gel at 25 ℃ for 0h, and FIG. 16(d) is a foam gel heated at 80 ℃ for 24 h.

FIG. 17 is a foam gel plugging performance evaluation experimental device.

FIG. 18 shows the properties of plugging a foamed gel with different opening degrees, wherein the opening degree of the slit shown in FIG. 18(a) is 0.1mm, the opening degree of the slit shown in FIG. 18(b) is 0.3mm, and the opening degree of the slit shown in FIG. 18(c) is 0.5 mm.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

In the following examples, crosslinking agent A was resorcinol and crosslinking agent B was formaldehyde.

The polymer used in the following examples is polyacrylamide KYPAM with a molecular weight of 2500 to 2800 ten thousand.