Preparation method of gel foam carrying modified molybdenum disulfide system
阅读说明：本技术 一种凝胶泡沫携带改性二硫化钼体系的制备方法 (Preparation method of gel foam carrying modified molybdenum disulfide system ) 是由 侯吉瑞 屈鸣 许杰 许志辉 张工厂 刘学杰 刘坤岳 许金梦 黄宁 于 2019-08-08 设计创作，主要内容包括：本发明公开了一种凝胶泡沫携带改性二硫化钼体系的制备方法,涉及油田开采技术领域,包括以下步骤：(1)改性MoS<Sub>2</Sub>的制备；(2)改性MoS<Sub>2</Sub>悬浮液的制备；(3)淀粉凝胶的制备；(4)凝胶泡沫携带改性二硫化钼体系的制备。本发明在凝胶泡沫基础上,首创了凝胶泡沫复配改性二硫化钼体系,加强了凝胶泡沫的稳定性和持久性。经研究发现,凝胶泡沫复配改性二硫化钼体系在没有破坏泡沫原有性质下成功将泡沫析液半衰期提高了一倍,对凝胶泡沫稳定进行了一次创新的突破。(The invention discloses a preparation method of a gel foam carrying modified molybdenum disulfide system, which relates to the technical field of oil field exploitation and comprises the following steps of (1) preparation of modified MoS 2 , (2) preparation of modified MoS 2 suspension, (3) preparation of starch gel, and (4) preparation of a gel foam carrying modified molybdenum disulfide system.)
1. A preparation method of a gel foam carrying modified molybdenum disulfide system is characterized by comprising the following steps: the method comprises the following steps:
(1) Preparing modified MoS 2, namely adding Cetyl Trimethyl Ammonium Bromide (CTAB) into deionized water to obtain a CTAB solution, dispersing hydrophilic MoS 2 nanosheets into the other part of deionized water with the same amount to obtain a MoS 2 nanosheet dispersion, adding the CTAB solution into the MoS 2 nanosheet dispersion, continuously stirring, and finally washing and drying to obtain modified MoS 2 powder;
(2) Preparing modified MoS 2 suspension, namely mixing the prepared modified MoS 2 with formation water, and then adding alkylphenol ethoxylates to obtain modified MoS 2 suspension;
(3) Preparation of starch gel: uniformly stirring alpha-modified starch and Polyacrylamide (PAM) in deionized water, adding N, N' -methylene bisacrylamide, continuously stirring, slowly adding an initiator, transferring to a closed container, putting into an oven, heating and gelatinizing;
(4) And (3) preparing a gel foam carrying modified molybdenum disulfide system, namely adding the prepared starch gel into tap water, adding an anionic temperature-resistant salt-resistant foaming agent, stirring, and adding the modified MoS 2 suspension after the foam is prepared to obtain the gel foam carrying modified molybdenum disulfide system.
2. The preparation method according to claim 1, wherein the hydrophilic MoS 2 nanosheets prepared in step (1) are prepared by dissolving a molybdenum source and a sulfur source in deionized water, then autoclaving at a high pressure of 180 ℃ and 220 ℃ and a pressure of 2MPa, cooling the solution to room temperature, washing, and dialyzing with ultrapure water to obtain MoS 2 nanosheets.
3. The method of claim 2, wherein: the molybdenum source is selected from one of hexaammonium heptamolybdate, ammonium tetrathiomolybdate and molybdenum (II) acetate dimer; the sulfur source is selected from one of thiourea, sulfur powder and potassium thiocyanate; the molar ratio of the molybdenum source to the sulfur source was 1: 7.
4. the preparation method according to claim 1, wherein the modified MoS 2 is used in the step (2) in an amount of 0.005 wt% based on the mass of the formation water, and the mass ratio of the modified MoS 2 to the alkylphenol ethoxylates is 1: 2.
5. The method of claim 1, wherein: the alkylphenol polyoxyethylene ether is preferably OP-10.
6. The method of claim 1, wherein: in the step (3), the mass ratio of the alpha-modified starch to the polyacrylamide to the N, N' -methylene bisacrylamide to the initiator is 4:4:0.1: 0.01.
7. The method of claim 1, wherein: the initiator in the step (3) is potassium persulfate.
8. The method of claim 1, wherein: the temperature of the oven in the step (3) is 60-150 ℃.
9. The preparation method according to claim 1, wherein the mass ratio of the starch gel solution to the tap water in the step (4) is 1:1-2, the amount of the anionic temperature-resistant salt-resistant foaming agent is 0.2 wt% of the total mass of the starch gel solution and the tap water, and the amount of the modified MoS 2 suspension is 0.005 wt% of the total mass of the starch gel solution and the tap water.
10. The method of claim 1, wherein: in the step (4), the anionic temperature-resistant salt-tolerant foaming agent is alpha-sodium alkenyl sulfonate AOS.
The technical field is as follows:
the invention relates to the technical field of oilfield exploitation, in particular to a preparation method of a gel foam carrying modified molybdenum disulfide system.
Background art:
The conventional miscible-phase gas-drive oil-increasing technology for oil field exploitation at present is comprehensively popularized and put into use in a large range, and comprises LPG flooding, rich gas flooding, high-pressure dry gas flooding, CO 2 flooding and N 2 flooding, wherein the N 2 flooding is mainly used for the application of oil field exploitation due to the advantages of low price, easy availability, non-combustibility, non-explosion, no toxicity, no corrosion and low oil-water solubility.
Gas injection is one of the important technologies for improving the recovery ratio (EOR) of carbonate reservoirs, and compared with thermal oil recovery and chemical flooding, the gas injection is more remarkable in the actual production effect of a mine field and has a wider application range. Gas injection can effectively enlarge the spread volume of crude oil in the stratum, and residual oil at the high part of an oil reservoir is started under the action of gravity differentiation, but the problem of gas channeling exists, so that the maximum performance of the oil displacement effect is influenced. Therefore, temperature-resistant salt-tolerant micro-dispersed gel reinforced foam is researched and developed, and the adaptability and the plugging capability of a gel foam system are verified through indoor tests and mine field tests, so that the oil displacement efficiency of attic oil at the top is effectively improved, and the like.
In carbonate formation foam displacement, foam first enters a large flow channel, and the specific process can be roughly divided into a stable foam zone, a foam-oil mixing zone and a pure oil zone. Because of the instability of foam in oil, the foam at the front edge of the foam displacement is very easy to break after contacting with crude oil, and released nitrogen is not easy to dissolve in oil, enters a high construction position under the action of gravity differentiation and is continuously accumulated to form a secondary gas cap to displace attic oil; along with the continuous injection of foam, crude oil is continuously driven out under the combined action of the foam and gas, the oil saturation in the large channel is reduced, the foam stability is enhanced and is accumulated in the flow channel, the accumulation action increases the resistance of the follow-up foam to the large channel, and the gas is blocked, so that the fluidity of the gas is controlled, the gas interface can be uniformly reduced, and the occurrence of gas channeling is effectively inhibited.
At present, the mainly adopted stable foam system mostly adopts multi-slug and multi-turn injection or uses high-viscosity polymer such as petroleum-grade scleroglucan and the like as base liquid of gel foam. By means of comprehensive mine field effect analysis, the gel foam system has been successful in stages and starts to be popularized in a large range. However, in order to enhance the stability of the foam and improve the half-life of the liquid separation, a large number of injection modes and a high-concentration injection mode are adopted, so that the investment of labor and cost is increased, the fault tolerance of the actual production capacity of a mine site is reduced, and the stability of the foam is limited at present due to various uncertain factors, heterogeneity of different landforms, irregular crack distribution, solution breaking, a river and the like (mainly carbonate rock stratum).
The invention content is as follows:
The technical problem to be solved by the invention is to provide a preparation method of a gel foam carrying modified molybdenum disulfide system, the method has definite operation parameters and good repeatability, and the prepared gel foam compounding modified molybdenum disulfide system successfully improves the half-life of foam liquid separation by one time without destroying the original properties of foam.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
A preparation method of a gel foam carrying modified molybdenum disulfide system comprises the following steps:
(1) Preparing modified MoS 2, namely adding Cetyl Trimethyl Ammonium Bromide (CTAB) into deionized water to obtain a CTAB solution, dispersing hydrophilic MoS 2 nanosheets into the other part of deionized water with the same amount to obtain a MoS 2 nanosheet dispersion, adding the CTAB solution into the MoS 2 nanosheet dispersion, continuously stirring, and finally washing and drying to obtain modified MoS 2 powder;
(2) Preparing modified MoS 2 suspension, namely mixing the prepared modified MoS 2 with formation water, and then adding alkylphenol ethoxylates to obtain modified MoS 2 suspension;
(3) Preparation of starch gel: uniformly stirring alpha-modified starch and Polyacrylamide (PAM) in deionized water, adding N, N' -methylene bisacrylamide, continuously stirring, slowly adding an initiator, transferring to a closed container, putting into an oven, heating and gelatinizing;
(4) And (3) preparing a gel foam carrying modified molybdenum disulfide system, namely adding the prepared starch gel into tap water, adding an anionic temperature-resistant salt-resistant foaming agent, stirring, and adding the modified MoS 2 suspension after the foam is prepared to obtain the gel foam carrying modified molybdenum disulfide system.
The preparation method of the hydrophilic MoS 2 nanosheet in the step (1) comprises the steps of dissolving a molybdenum source and a sulfur source in deionized water, then carrying out high-pressure autoclaving at the temperature of 180 ℃ and the temperature of 220 ℃ and under the pressure of 2MPa, cooling the solution to room temperature, washing, and dialyzing with ultrapure water to obtain the MoS 2 nanosheet.
The molybdenum source is selected from one of hexaammonium heptamolybdate, ammonium tetrathiomolybdate and molybdenum (II) acetate dimer; the sulfur source is selected from one of thiourea, sulfur powder and potassium thiocyanate; the molar ratio of the molybdenum source to the sulfur source was 1: 7.
the amount of the modified MoS 2 in the step (2) is 0.005 wt%, calculated by the mass of the formation water, and the mass ratio of the modified MoS 2 to the alkylphenol ethoxylates is 1: 2.
The alkylphenol polyoxyethylene ether is preferably OP-10.
In the step (3), the mass ratio of the alpha-modified starch to the polyacrylamide to the N, N' -methylene bisacrylamide to the initiator is 4:4:0.1: 0.01. The alpha-modified starch is provided for the chemical industry of Beijing Hapeng.
The initiator in the step (3) is potassium persulfate.
The temperature of the oven in the step (3) is 60-150 ℃.
In the step (4), the mass ratio of the starch gel solution to the tap water is 1:1-2, the dosage of the anionic temperature-resistant salt-resistant foaming agent is 0.2 wt% of the total mass of the starch gel solution and the tap water, and the dosage of the modified MoS 2 suspension is 0.005 wt% of the total mass of the starch gel solution and the tap water.
in the step (4), the anionic temperature-resistant salt-tolerant foaming agent is alpha-sodium alkenyl sulfonate AOS. The molecular structure of the anionic temperature-resistant salt-resistant foaming agent is composed of nonpolar oleophilic (hydrophobic) groups and polar hydrophilic (oleophobic) groups, and a hydrophilic and oleophilic so-called 'amphiphilic structure' molecule is formed.
according to researches, the preparation method of the nano molybdenum disulfide is divided into three major types, namely a physical method, a chemical method and a heavy stacking (intercalation) composite method, the preparation of the nano molybdenum disulfide is carried out by combining laboratory preparation conditions, preferably a two-step reduction method (one of the chemical methods), firstly, a high-purity molybdenum source (sodium molybdate, ammonium molybdate and the like) is selected to react with a sulfur source (sodium sulfide and ammonium sulfide), a brownish molybdenum trisulfide (MoS 3) is obtained as an initial compound (precursor) after acidification and precipitation reaction, then, hydrogen is introduced at a high temperature to reduce MoS 3 to obtain the nano molybdenum disulfide (MoS 2), and the reaction equation is as follows (the sodium molybdate and the ammonium sulfide are adopted in the experiment of the group):
4(NH4)2S+Na2MoO4+4H2O→8NH4OH+Na2MoS4，
H2+Na2MoS4＝MoS3↓+H2S↑+2Na，
H2+MoS3＝MoS2↓+H2S
the modified molybdenum disulfide nanosheet can improve foam stability and oil resistance, and can be carried to a high part of an oil reservoir to emulsify and reduce viscosity of high-part crude oil; the 0.005% modified molybdenum disulfide solution is added into the foam, so that the half-life period of the foam liquid separation is prolonged, and the half-life period of the original liquid separation is prolonged by one time. The foam added with the modified molybdenum disulfide solution can quickly enter an oil phase at the bottom layer to form 'foam oil', the viscosity of crude oil is reduced, the fluidity of the crude oil is improved, and the transition band formed by the formed 'foam oil' is favorable for expanding the swept range.
The invention has the beneficial effects that: on the basis of the gel foam, the invention creates a gel foam compound modified molybdenum disulfide system for the first time, and enhances the stability and durability of the gel foam. Researches show that the gel foam compound modified molybdenum disulfide system successfully improves the half-life period of foam liquid separation by one time without destroying the original properties of the foam, and makes an innovative breakthrough on the stability of the gel foam.
Description of the drawings:
FIG. 1 is a comparison of the emulsification rate and water separation rate of foam concentrate carried MoS 2 and single MoS 2 solutions;
FIG. 2 is a gel foam carrying modified MoS 2 to form a "foam oil";
FIG. 3 is a colloidal foam carrying modified MoS 2;
FIG. 4 is a graph of the drag reduction capability of a gel foam system;
FIG. 5 is a comparison of the adsorption capacity of different gel foam systems.
The specific implementation mode is as follows:
In order to make the technical means, the original characteristics, the achieved purposes and the effects of the invention easy to understand, the invention is further explained by combining the specific embodiments and the drawings.