CN112480888B - Underground gel valve and preparation method thereof - Google Patents

Underground gel valve and preparation method thereof Download PDF

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CN112480888B
CN112480888B CN202011361128.2A CN202011361128A CN112480888B CN 112480888 B CN112480888 B CN 112480888B CN 202011361128 A CN202011361128 A CN 202011361128A CN 112480888 B CN112480888 B CN 112480888B
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solution
gel
water
valve
underground
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CN112480888A (en
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聂法健
马玺
王振宇
毛洪超
张津滔
王艳平
司晓菊
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Puyang Huacheng Hengye Petroleum Technology Development Co ltd
Yangtze University
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Puyang Huacheng Hengye Petroleum Technology Development Co ltd
Yangtze University
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    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/42Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells
    • C09K8/426Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells for plugging
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52Amides or imides
    • C08F220/54Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/56Acrylamide; Methacrylamide
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52Amides or imides
    • C08F220/54Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/58Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
    • C08F220/585Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine and containing other heteroatoms, e.g. 2-acrylamido-2-methylpropane sulfonic acid [AMPS]
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    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K8/00Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/42Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells
    • C09K8/44Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing organic binders only
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/42Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells
    • C09K8/46Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing inorganic binders, e.g. Portland cement
    • C09K8/467Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing inorganic binders, e.g. Portland cement containing additives for specific purposes
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00Sealing or packing boreholes or wells
    • E21B33/10Sealing or packing boreholes or wells in the borehole
    • E21B33/13Methods or devices for cementing, for plugging holes, crevices or the like
    • E21B33/138Plastering the borehole wall; Injecting into the formation
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B34/00Valve arrangements for boreholes or wells
    • E21B34/06Valve arrangements for boreholes or wells in wells
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2208/00Aspects relating to compositions of drilling or well treatment fluids
    • C09K2208/26Gel breakers other than bacteria or enzymes

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Abstract

The invention relates to an underground gel valve which comprises the following raw materials in percentage by mass: 0.8-1.1% of supramolecular polyacrylamide, 0.2-0.25% of stabilizing agent, 0.5-0.65% of cross-linking agent, 0.05-0.1% of gel breaker and the balance of water. The invention also provides a preparation method of the underground gel valve. The gel valve has the advantages of strong operability, high reliability, low cost, no damage to a reservoir stratum, good applicability and the like, obviously improves the performances such as air tightness, pressure resistance, stability, pipe wall adhesion and the like, has the same excellent temperature resistance and gel breaking performance, greatly improves the applicability of underbalanced well completion and other technologies, shortens the drilling period, has good safety, reduces the drilling cost, improves the economic benefit and has great application prospect.

Description

Underground gel valve and preparation method thereof
Technical Field
The invention belongs to the technical field of gel valves, and particularly relates to an underground gel valve and a preparation method thereof.
Background
At present, the technique of open hole well completion, tail pipe unfixed perforation well completion, slotted liner well completion, casing valve screen pipe well completion and the like is mainly adopted for the unbalanced well completion at home and abroad. The open hole well completion and tail pipe unfixed perforation well completion are simple in operation and low in cost, but the well wall cannot be stably supported, and long-term stable development of an oil well is not facilitated; slotted liner completions and cased-hole screen completions can provide open hole support and collapse prevention, but the completion mode is high in cost, once a mechanical tool has a problem in the downhole, the replacement process is complex or difficult to replace, the well killing medium used in the drilling completion and well killing operation processes of the oil and gas wells is drilling mud or well killing fluid, and a conventional well killing construction method matched with the well killing medium is adopted. The conventional kill construction method damages the reservoir, the construction cost is high, and the construction operation is complex. In the process of well drilling, well completion and well repair, pipe string pulling operation is frequently carried out, and in order to ensure the operation safety, high-density liquid such as slurry, well killing liquid and the like is required to kill the well. And the excessive drilling fluid density of some deep wells and complex well sections can induce and aggravate the occurrence of lost circulation. Particularly in oil reservoir areas of Mongolia, gansu and Shaanxi in China, well leakage caused by the reasons becomes one of bottleneck problems affecting the drilling speed and increasing the drilling cost. In addition, there is a risk of gas escaping outwards during completion and workover operations in wells with large production of gas from the formation. In the underbalance of the protective reservoir and gas drilling construction, expensive casing valve equipment is required to be used for blocking underground gas, and the construction safety is ensured.
Disclosure of Invention
The invention provides an underground gel valve and a preparation method thereof aiming at the technical problems in the prior art, and the underground gel valve can realize safe drilling, completion and killing operations in the processes of drilling, completion and workover; the mud, the well killing fluid and the reservoir are effectively separated, the upper well killing fluid is effectively prevented from entering the stratum, and gases such as hydrogen sulfide in the stratum can be prevented from escaping outwards; the device replaces technical equipment such as a casing valve and the like, and avoids reservoir pollution in the process of drilling, well completion and well repair operation.
The technical scheme for solving the technical problems is as follows:
the downhole gel valve comprises the following raw materials in percentage by mass: 0.8-1.1% of supramolecular polyacrylamide, 0.2-0.25% of stabilizing agent, 0.5-0.65% of cross-linking agent, 0.05-0.1% of gel breaker and the balance of water.
On the basis of the technical scheme, the invention can be further improved as follows.
Further, the synthesis method of the supramolecular polyacrylamide comprises the following steps:
1) Preparing an oil phase: fully dissolving saturated petroleum fractions, span 80 and tween 80 in a mass ratio of 25;
2) Preparing aqueous solutions of the following four auxiliaries: 10% disodium ethylene diamine tetraacetate solution, 2% sodium bisulfite solution, 15% sodium metabisulfite solution and 20% sodium hydroxide solution;
3) Preparing a water phase: adding acrylamide and 2-acrylamido-2-methylpropanesulfonic acid in a mass ratio of 1; then adding the 10% disodium ethylene diamine tetraacetate solution and the 0.4% tetramethyl ethylene diamine solution in the step 2), and adjusting the pH value of the solution to 7 by using the 20% sodium hydroxide solution in the step 2) to obtain a water phase; wherein the mass ratio of the deionized water to the 10% disodium ethylene diamine tetraacetate solution to the acrylamide is 100:1, the mass-to-volume ratio (g/. Mu.l) of acrylamide to a 0.4% tetramethylethylenediamine solution is 2:1;
4) Emulsification: pouring the water phase in the step 3) into the oil phase in the step 1), and emulsifying for 20min to obtain an emulsion with the viscosity of more than 200mPa & s; continuously adjusting the position of the reactor in the emulsification process to enable the liquid level to present ripples; wherein the mass ratio of the saturated petroleum fraction to the acrylamide is 5;
5) Polymerization: pouring the emulsion into a reaction kettle, stirring at the stirring speed of 110-130r/min for 1h, and continuously introducing nitrogen to remove oxygen; simultaneously filling nitrogen into the 2% sodium bisulfite solution in the step 2) to remove oxygen; cooling the reaction kettle to reduce the internal temperature to 12 ℃, and then adding 2% of deoxygenated sodium bisulfite solution and 15% of sodium metabisulfite solution at the speed of 3-5ml/h in sequence; adding octyl phenol polyoxyethylene ether-10 into the reaction kettle, stirring for 1h, and stopping filling nitrogen to obtain supermolecule polyacrylamide; wherein the mass ratio of 2% sodium bisulfite solution, 15% sodium metabisulfite solution, octyl phenol polyoxyethylene ether-10 and acrylamide is 3:5:25:150.
Further, in the step 5), the early flow of the nitrogen is 6L/min; after the deoxygenated 2% sodium bisulfite solution is added into the reaction kettle, the nitrogen flow is 2-3L/min.
Further, the stabilizer comprises the following raw materials in percentage by mass: 30% choline chloride, 10% kcl (saturated) and 60% deionized water.
Further, the cross-linking agent comprises the following raw materials in percentage by mass: 10% sodium lauryl sulfate, 20% isopropyl alcohol and 70% deionized water.
Further, the preparation method of the cross-linking agent comprises the following steps: 1) Putting the three-necked bottle into a water bath kettle, and erecting a nitrogen introducing, stirring and condensing reflux device; 2) Respectively weighing deionized water, isopropanol and sodium dodecyl sulfate in a mass ratio of 7.
Further, the gel breaker is ammonium persulfate.
The invention also provides a preparation method of the underground gel valve, which comprises the following steps:
1) The preparation method of the gel valve comprises the following steps: connecting pipeline, starting pump circulation, and stabilizing discharge capacity of 0.8-1m 3 Sequentially adding a dry powder thickener through a jet pump, circularly dissolving for 20min, connecting a well cementation cement truck and a ground water pool, circularly stirring, adding water into the water pool according to the designed dosage, and adding supramolecular polyacrylamide and a stabilizer into the water under the stirring condition to prepare a uniform base liquid, wherein the base liquid accounts for 70%; then preparing a crosslinking solution, wherein the volume of the crosslinking solution is 20% of that of the downhole gel valve, and adding a crosslinking agent into water under the stirring condition to prepare a uniform solution; finally preparing a gel breaking solution, breakingThe volume of the glue solution is 10 percent of the volume of the underground gel valve, and the gel breaker ammonium persulfate is added into water under the stirring condition to prepare a uniform solution;
2) And (3) injection process of the gel valve: connecting a cement truck and a high-pressure proportional pump with a tee joint through a pipeline, wherein the outlet end of the tee joint is connected with the annular space or the oil pipe of the operation well; after the pipeline is tested to be qualified, simultaneously mixing the base fluid and the crosslinking fluid by using a cement truck and a high-pressure proportioning pump, continuously injecting the mixture into the underground, then injecting well killing fluid or clear water or slurry, and replacing the mixed solution of the base fluid and the crosslinking fluid to a preset position of a shaft; the injected base fluid and the injected cross-linking fluid form a downhole gel valve with higher viscosity at the temperature of 30-150 ℃ for 20-50min, and the downhole gel valve blocks a well section as long as 130-500 m;
3) When the gel needs to be broken, the gel breaking liquid is injected into the underground gel valve with higher viscosity through the cement truck, and the underground gel valve breaks the gel to form liquid with lower viscosity.
Further, in the step 1), the preparation equipment of the jelly glue valve comprises a stirrer, a tank truck and a water pool.
Further, in the step 2), the injection equipment of the gel valve comprises a cement truck, a high-pressure proportioning pump, a water tank and a tee joint.
The invention has the beneficial effects that: the gel valve has the advantages of strong operability, high reliability, low cost, no damage to a reservoir stratum, good applicability and the like, obviously improves the performances such as air tightness, pressure resistance, stability, pipe wall adhesion and the like, has excellent temperature resistance and gel breaking performance, greatly improves the applicability of underbalanced well completion and other technologies, shortens the drilling period, has good safety, reduces the drilling cost, improves the economic benefit and has great application prospect.
Detailed Description
The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
It should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" are intended to be construed broadly, as if they were connected either fixedly or removably, or as integrally formed structures. The specific meaning of such terms in this patent may be understood by one of ordinary skill in the art as appropriate.
All percentages used in the present invention are mass percentages unless otherwise indicated.
The gel valve is mainly used for sealing a shaft, so that the purposes of preventing oil and gas from upward fleeing and preventing drilling fluid from being lost are achieved. Thereby protecting the oil gas stability of the reservoir, having great protection effect on the permeability leakage stratum and having the functions of leakage prevention and leakage stoppage.
The invention designs an underground gel valve which comprises the following raw materials in percentage by mass: 0.8-1.1% of supramolecular polyacrylamide, 0.2-0.25% of stabilizing agent, 0.5-0.65% of cross-linking agent, 0.05-0.1% of gel breaker and the balance of water.
The synthesis method of the supramolecular polyacrylamide comprises the following steps:
1) Preparing an oil phase: fully dissolving saturated petroleum fractions, span 80 and Tween 80 in a mass ratio of 25;
2) Preparing aqueous solutions of the following four auxiliaries: 10% disodium ethylene diamine tetraacetate solution, 2% sodium bisulfite solution, 15% sodium metabisulfite solution and 20% sodium hydroxide solution;
3) Preparing a water phase: adding acrylamide and 2-acrylamido-2-methylpropanesulfonic acid in a mass ratio of 1; adding the 10% disodium ethylene diamine tetraacetate solution and the 0.4% tetramethyl ethylene diamine solution in the step 2), and adjusting the pH value of the solution to be 7 by using the 20% sodium hydroxide solution in the step 2) to obtain a water phase; wherein the mass ratio of the deionized water to the 10% disodium ethylene diamine tetraacetate solution to the acrylamide is 100:1, wherein the mass volume ratio (g/mu l) of acrylamide to a 0.4% tetramethylethylenediamine solution is 2;
4) Emulsification: pouring the water phase obtained in the step 3) into the oil phase obtained in the step 1), and emulsifying for 20min to obtain an emulsion with the viscosity of more than 200mPa & s; continuously adjusting the position of the reactor in the emulsification process to enable the liquid level to present ripples; wherein the mass ratio of the saturated petroleum fraction to the acrylamide is 5;
5) Polymerization: pouring the emulsion into a reaction kettle, stirring at the stirring speed of 110-130r/min for 1h, and continuously introducing nitrogen to remove oxygen; simultaneously filling nitrogen into the 2% sodium bisulfite solution in the step 2) to remove oxygen; cooling the reaction kettle to reduce the internal temperature to 12 ℃, and then adding 2% of deoxygenated sodium bisulfite solution and 15% of sodium metabisulfite solution at the speed of 3-5ml/h in sequence; adding octyl phenol polyoxyethylene ether-10 into the reaction kettle, stirring for 1h, and stopping filling nitrogen to obtain a polymer thickener-supramolecular polyacrylamide; wherein the mass ratio of 2% sodium bisulfite solution, 15% sodium metabisulfite solution, octyl phenol polyoxyethylene ether-10 and acrylamide is 3:5:25:150.
In the step 5), the early flow of the nitrogen is 6L/min; after the deoxygenated 2% sodium bisulfite solution is added into the reaction kettle, the nitrogen flow is 2-3L/min.
The polymer thickener, namely the supramolecular polyacrylamide, is a high molecular polymer formed by copolymerizing a multifunctional cationic surface active monomer and a water-soluble polymer, wherein a matrix monomer is assembled on the surface of the polymer, a hydrophobic group is wrapped in the assembly, and a reversible space network structure is formed by utilizing the chemical action among molecular bonds, so that the viscoelasticity of a colloid and the adhesive capacity to a tubular column are improved. The applicable temperature range is 30-150 ℃, and the mineralization resistance degree is (15 multiplied by 10) 4 mg/LCa 2+ 、Mg 2+ ) Acid and alkali resistance (pH value is 5-12), and oil-resistant substance immersion dirt resistance (the content of oil substances can reach 26%, and the plugging performance of the oil-resistant substance immersion dirt-resistant agent is not influenced).
The stabilizer comprises the following raw materials in percentage by mass: 30% choline chloride, 10% kcl (saturated) and 60% deionized water.
The gel breaker is ammonium persulfate.
The cross-linking agent comprises the following raw materials in percentage by mass: 10% sodium lauryl sulfate, 20% isopropyl alcohol and 70% deionized water.
The preparation method of the cross-linking agent comprises the following steps: 1) Putting the three-necked bottle into a water bath kettle, and erecting a nitrogen introducing, stirring and condensing reflux device; 2) Respectively weighing deionized water, isopropanol and sodium dodecyl sulfate in a mass ratio of 7.
The inventor firstly proposes a binary complex crosslinking idea, and a large amount of experimental researches show that when supramolecular polyacrylamide and a crosslinking agent simultaneously have long polar molecular chains, the crosslinking agent can interact with polyacrylamide molecules with a longer spatial distance under a low-concentration condition, so that the crosslinking performance of a system is remarkably improved, and unexpected technical effects are achieved. Based on the above, the inventor creatively provides the preparation method of the supramolecular polyacrylamide and the cross-linking agent, and the prepared supramolecular polyacrylamide and the cross-linking agent both have long polar molecular chains; and the proportion and the preparation method of the underground gel valve are improved to obtain the underground gel valve which has high crosslinking viscosity and compressive strength and can not cause damage to a reservoir by the gel breaking liquid.
The underground gel valve forms a space network structure with extremely strong acting force and the cohesive force with the well wall through cross-linking reaction, thereby meeting the requirement of packing pressure. The gel valve utilizes the strength of the gel valve and the adhesive force of the gel valve and the well wall to seal off the underground pressure, eliminates the reservoir damage caused by the overlarge underground pressure, protects the reservoir and avoids the drilling accidents caused by the failure of the casing valve. The underground gel valve is prepared underground, a high-strength gel section is formed in a shaft between the middle of a reservoir and the bottom of an oil pipe column, and the shaft is safely sealed in the drilling, well completion and well repair processes.
The invention also provides a preparation method of the underground gel valve, which comprises the following steps:
1) The preparation method of the gel valve comprises the following steps: connecting pipeline, starting pump circulation, and stabilizing discharge capacity of 0.8-1m 3 The dry powder thickener is sequentially added through a jet pump to be circularly dissolved for 20min, and is circularly stirred by connecting a well cementation cement truck and a ground water pool, and is added into the water pool according to the designed dosageAdding supramolecular polyacrylamide and a stabilizer into water under the stirring condition to prepare uniform base liquid, wherein the base liquid accounts for 70%; then preparing a cross-linking solution, wherein the volume of the cross-linking solution is 20% of that of the underground gel valve, and adding a cross-linking agent into water under the stirring condition to prepare a uniform solution; finally, preparing a gel breaking solution, wherein the volume of the gel breaking solution is 10% of that of the underground gel valve, and adding ammonium persulfate of the gel breaking agent into water under the stirring condition to prepare a uniform solution;
2) And (3) injection process of the gel valve: connecting a cement truck and a high-pressure proportional pump with a tee joint through a pipeline, wherein the outlet end of the tee joint is connected with the annular space or the oil pipe of the operation well; after the pipeline is tested to be qualified, simultaneously mixing the base fluid and the crosslinking fluid by using a cement truck and a high-pressure proportioning pump, continuously injecting the mixture into the underground, then injecting well killing fluid or clear water or slurry, and replacing the mixed solution of the base fluid and the crosslinking fluid to a preset position of a shaft; the injected base fluid and the injected cross-linking fluid form a downhole gel valve with higher viscosity at the temperature of 30-150 ℃ for 20-50min, and the downhole gel valve blocks a well section with the length of 130-500 m;
3) When the gel needs to be broken, the gel breaking liquid is injected into the underground gel valve with higher viscosity through the cement truck, and the underground gel valve breaks the gel to form liquid with lower viscosity.
In the step 1), the preparation equipment of the jelly glue valve comprises a stirrer, a tank truck and a water tank.
In the step 2), the injection equipment of the gel valve comprises a cement truck, a high-pressure proportioning pump, a water tank and a tee joint.
The performance of the underground gel valve is as follows: (1) applicable environment: the applicable temperature range is 30-150 ℃, and the mineralization resistance is 15 multiplied by 10 4 mg/L Ca 2+ 、Mg 2+ ) Acid and alkali resistance (pH value is 5-12), and oil-resistant substance immersion dirt resistance (the content of oil substances can reach 30 percent, and the plugging performance of the oil-resistant substance immersion dirt resistance is not influenced); (2) pumpability: the colloid is easy to prepare and pump in the initial state, and has good fluidity and viscosity of 10-350mPa & s; (3) airtightness and pressure resistance: the compression strength of colloid in the shaft is more than 2MPa/10m; (4) strong adhesion of tube wall: the colloid is tightly adhered to the pipe wall, so that the gas channeling of the pipe wall and the colloid slippage of the pipe wall are effectively prevented; (5) stability: the stable gelling time exceeds 15 days (the performance of the gel valve is stable under certain temperature and pressure) The operation requirement is met; (6) controllability of gelling time; controlling the gelling time to be 20-50min; (7) gel breaking property: and after the operation is finished, injecting a gel breaking solution, wherein the viscosity of the gel breaking solution after gel breaking is less than 5mPa & s, and the reservoir is not damaged.
The underground gel valve and the preparation method thereof are applied to the drilling, well completion or well repair process. The underground gel valve adopting the technical scheme of the invention has the following effects: (1) Safe drilling, completion and killing operations in the processes of drilling, completion and workover are realized; (2) The mud, the well killing fluid and the reservoir are effectively separated, the upper well killing fluid is effectively prevented from entering the stratum, and gases such as hydrogen sulfide in the stratum can be prevented from escaping outwards; (3) The underground gel valve of the technical scheme of the invention replaces technical equipment such as a mechanical casing valve and the like, realizes the requirements of sealing a shaft safely and at low cost in the underbalanced drilling process and the like, and simultaneously effectively avoids reservoir pollution in the drilling, well completion and workover operation processes. The defects that the conventional kill construction method damages the reservoir and the construction cost is high are overcome.
Example 1
The downhole gel valve designed by the embodiment comprises the following raw materials in percentage by mass: 0.8% of supramolecular polyacrylamide, 0.2% of stabilizing agent, 0.5% of cross-linking agent, 0.05% of gel breaker and the balance of water.
The synthesis method of the supramolecular polyacrylamide disclosed by the embodiment comprises the following steps of:
1) Preparing an oil phase: fully dissolving 500g of saturated petroleum fraction, 60g of span 80 and 40g of Tween 80, and covering with a preservative film to obtain an oil phase;
2) Preparing aqueous solutions of the following four auxiliaries: 10% disodium ethylene diamine tetraacetate solution, 2% sodium bisulfite solution, 15% sodium metabisulfite solution and 20% sodium hydroxide solution;
3) Preparing an aqueous phase: adding 300g of acrylamide and 300g of 2-acrylamido-2-methylpropanesulfonic acid into 400g of deionized water, stirring uniformly, adding the 20% sodium hydroxide solution obtained in the step 2), and adjusting the pH value of the solution to 6; adding 4g of 10% disodium ethylene diamine tetraacetate solution and 150 mu l of 0.4% tetramethylethylenediamine solution in the step 2), and adjusting the pH value of the solution to 7 by using 20% sodium hydroxide solution in the step 2) to obtain a water phase;
4) Emulsification: pouring the water phase in the step 3) into the oil phase in the step 1), and emulsifying for 20min to obtain an emulsion with the viscosity of more than 200mPa & s; continuously adjusting the position of the reactor in the emulsification process to enable the liquid level to present ripples;
5) Polymerization: pouring the emulsion into a reaction kettle, stirring at the stirring speed of 110-130r/min for 1h, and continuously introducing nitrogen to remove oxygen; simultaneously filling nitrogen into the 2% sodium bisulfite solution in the step 2) to remove oxygen; cooling the reaction kettle to reduce the internal temperature to 12 ℃, and then sequentially adding 6g of deoxygenated 2% sodium bisulfite solution and 10g of 15% sodium metabisulfite solution at the speed of 3-5ml/h through a micro-injection pump; and then adding 50g of octyl phenol polyoxyethylene ether-10 into the reaction kettle by using a normal pressure dropping funnel, stirring for 1 hour, and stopping filling nitrogen to obtain the polymer thickener-supramolecular polyacrylamide.
In the step 5), the early flow of the nitrogen is 6L/min; after the deoxygenated 2% sodium bisulfite solution is added into the reaction kettle, the nitrogen flow is 2-3L/min.
The stabilizer comprises the following raw materials in percentage by mass: 30% choline chloride, 10% kcl (saturated) and 60% deionized water.
The cross-linking agent in the embodiment comprises the following raw materials in percentage by mass: 10% sodium lauryl sulfate, 20% isopropyl alcohol and 70% deionized water. The preparation method comprises the following steps: 1) Putting a 1000ml three-necked bottle into a water bath kettle, and erecting a nitrogen introducing, stirring and condensing reflux device; 2) Respectively weighing 350g of deionized water, 100g of isopropanol and 50g of sodium dodecyl sulfate, sequentially adding the deionized water, the isopropanol and the sodium dodecyl sulfate into a 1000ml three-necked bottle, sealing and stirring, introducing nitrogen, starting a water bath at the temperature of 50 +/-0.5 ℃, reacting for 2 hours at constant temperature, and after the reaction is finished, taking out the three-necked bottle, and cooling the liquid to obtain the cross-linking agent.
In this embodiment, the breaker is ammonium persulfate.
The preparation method of the downhole gel valve comprises the following steps:
1) The preparation method of the gel valve comprises the following steps: connecting pipeline, starting pump circulation, and stabilizing discharge capacity of 0.8-1m 3 Sequentially adding a dry powder thickener (supramolecular polyacrylamide) through a jet pump to circularly dissolve for 20min, connecting a well cementation cement truck and a ground water pool, circularly stirring, adding water into the water pool according to the designed amount, and adding the supramolecular polyacrylamide and a stabilizer into the water under the stirring condition to prepare a uniform base liquid, wherein the base liquid accounts for 70%; then preparing a crosslinking solution, wherein the volume of the crosslinking solution is 20% of that of the downhole gel valve, and adding a crosslinking agent into water under the stirring condition to prepare a uniform solution; finally, preparing a gel breaking solution, wherein the volume of the gel breaking solution is 10% of that of the underground gel valve, and adding ammonium persulfate of the gel breaking agent into water under the stirring condition to prepare a uniform solution;
2) And (3) injection process of the gel valve: connecting the cement truck and the high-pressure proportional pump with a tee joint through a pipeline, wherein the outlet end of the tee joint is connected with the working well annulus or an oil pipe; after the pipeline pressure test is qualified, simultaneously mixing the base fluid and the crosslinking fluid by using a cement truck and a high-pressure proportional pump, continuously injecting the mixture into the underground, then injecting well killing fluid or clear water or slurry, and replacing the mixed solution of the base fluid and the crosslinking fluid to a preset position of a shaft; the injected base fluid and the injected cross-linking fluid form a downhole gel valve with higher viscosity at the temperature of 150 ℃ for 20min, and the downhole gel valve blocks a well section with the length of 130 m;
3) When the gel needs to be broken, the gel breaking liquid is injected into the underground gel valve with higher viscosity through the cement truck, and the underground gel valve breaks the gel to form liquid with lower viscosity.
In the step 1), the preparation equipment of the jelly glue valve comprises a stirrer, a tank truck and a water tank. The base solution and the cross-linking agent are uniformly mixed by a stirrer, and the gelling quality is ensured.
In the step 2), the injection equipment of the gel valve comprises a cement truck, a high-pressure proportioning pump, a water tank and a tee joint.
The downhole gel valves designed in examples 2-5 and comparative examples 1-2 and the preparation method thereof are the same as those in example 1, and only part of parameters are different, as shown in table 1, which is not repeated herein. The performance of the downhole gel valves of examples 1-5 and comparative examples 1-2 was tested and the results are shown in table 1.
The pressure bearing capacity of the gel valve is required to be free from entering a rock core with the permeability of less than 300 millidarcy under the condition of pressure difference of 25MPa, and the gel valve does not move in the sleeve under the condition of pressure difference of 25 MPa.
And evaluating the damage of the gel breaking liquid to the reservoir after the gel breaking of the underground gel valve is finished through the core damage rate.
Comparative example 3
Chinese patent CN107011879B discloses a "high temperature resistant high strength composite cross-linked gel packing agent and preparation method", and example 1 in its specific implementation is taken as comparative example 3 of the present invention.
Adding 3.5g of polyacrylamide into 500g of water, stirring for dissolving, standing for aging for 24 hours to prepare a polymer solution, adding polyethyleneimine into water, and stirring to prepare a cross-linking agent solution with the micro mass fraction of 5%; adding 10g of cross-linking agent solution and 2.5g of hectorite into the polymer solution, stirring until the cross-linking agent solution and the hectorite are uniformly mixed, and adjusting the pH value of the polymer solution to 10 by using a sodium hydroxide solution with the mass fraction of 5%; then pouring the mixture into an aging tank, and reacting for 12 hours at a constant temperature of 130 ℃ to obtain the high-temperature high-strength composite cross-linking gel packing agent. The gel forming time of the gel packing agent at 130 ℃ is 32min, the gel is stably formed for 16 days at 130 ℃, 10% hydrochloric acid solution is added for gel breaking for 24 hours, and the sealing compressive strength is 0.015MPa/m.
TABLE 1
Figure BDA0002803976460000111
Figure BDA0002803976460000121
Referring to table 1, it can be seen from the data analysis of examples 1-5 and comparative examples 1-3 that the technical effect of example 1 in terms of the overall properties (e.g., air tightness and pressure resistance, stability) is the worst of the 5 examples. However, as can be seen from the comparison of the test data of example 1 and comparative examples 1 to 3, the technical effect of the technical solution of example 1 in the aspects of air tightness, pressure resistance, stability, pipe wall adhesion and the like is obviously better than that of comparative examples 1 to 3. Therefore, it can be confirmed that the technical solution of the present invention has a technical effect significantly superior to those of comparative examples 1 to 3. The underground gel valve adopting the technical scheme of the invention has the following unexpected technical effects: the air tightness, the pressure resistance, the stability, the pipe wall adhesion and other properties are obviously improved, the temperature resistance and the gel breaking property are excellent, and the technical problems in the prior art can be effectively solved. In addition, the technical characteristics of the technical scheme of the invention have synergistic effect.
The specific technology not described in the present invention is the prior art. The mechanisms, components and parts of the present invention which are not described in detail are all the existing structures which exist in the prior art. Can be purchased directly from the market.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (5)

1. The underground gel valve is characterized by comprising the following raw materials in percentage by mass: 0.8-1.1% of supramolecular polyacrylamide, 0.2-0.25% of stabilizing agent, 0.5-0.65% of cross-linking agent, 0.05-0.1% of gel breaker and the balance of water;
the synthesis method of the supramolecular polyacrylamide comprises the following steps:
1) Preparing an oil phase: fully dissolving saturated petroleum fractions, span 80 and Tween 80 in a mass ratio of 25;
2) Preparing aqueous solutions of the following four auxiliaries: 10% disodium ethylene diamine tetraacetate solution, 2% sodium bisulfite solution, 15% sodium metabisulfite solution and 20% sodium hydroxide solution;
3) Preparing a water phase: adding acrylamide and 2-acrylamido-2-methylpropanesulfonic acid in a mass ratio of 1; then adding the 10% disodium ethylene diamine tetraacetate solution and the 0.4% tetramethyl ethylene diamine solution in the step 2), and adjusting the pH value of the solution to 7 by using the 20% sodium hydroxide solution in the step 2) to obtain a water phase; wherein the mass ratio of the deionized water to the 10% disodium ethylene diamine tetraacetate solution to the acrylamide is 100;
4) Emulsification: pouring the water phase obtained in the step 3) into the oil phase obtained in the step 1), and emulsifying for 20min to obtain an emulsion with the viscosity of more than 200mPa & s; continuously adjusting the position of the reactor in the emulsification process to enable the liquid level to present ripples; wherein the mass ratio of the saturated petroleum fraction to the acrylamide is 5;
5) Polymerization: pouring the emulsion into a reaction kettle, stirring at the stirring speed of 110-130r/min for 1h, and continuously introducing nitrogen to remove oxygen; simultaneously filling nitrogen into the 2% sodium bisulfite solution in the step 2) to remove oxygen; cooling the reaction kettle to reduce the internal temperature to 12 ℃, and then adding 2% of deoxygenated sodium bisulfite solution and 15% of sodium metabisulfite solution at the speed of 3-5mL/h in sequence; adding octyl phenol polyoxyethylene ether-10 into the reaction kettle, stirring for 1h, and stopping filling nitrogen to obtain supermolecule polyacrylamide; wherein the mass ratio of the 2% sodium bisulfite solution, the 15% sodium metabisulfite solution, the octyl phenol polyoxyethylene ether-10 and the acrylamide is 3;
the stabilizer comprises the following raw materials in percentage by mass: 30% choline chloride, 10% saturated KCl solution and 60% deionized water;
the cross-linking agent comprises the following raw materials in percentage by mass: 10% sodium lauryl sulfate, 20% isopropanol and 70% deionized water;
the preparation method of the cross-linking agent comprises the following steps: 1) Putting the three-necked bottle into a water bath kettle, and erecting a nitrogen introducing, stirring and condensing reflux device; 2) Respectively weighing deionized water, isopropanol and sodium dodecyl sulfate in a mass ratio of 7;
the gel breaker is ammonium persulfate.
2. The downhole jelly valve of claim 1, wherein in step 5), the early flow rate of nitrogen is 6L/min; after the deoxygenated 2% sodium bisulfite solution is added into the reaction kettle, the nitrogen flow is 2-3L/min.
3. A method of making a downhole gel valve according to any of claims 1-2, comprising the steps of:
1) The preparation method of the gel valve comprises the following steps: connecting pipeline, starting pump circulation, and stabilizing discharge capacity of 0.8-1m 3 The method comprises the following steps of (1) min, sequentially adding a dry powder thickener through a jet pump, circularly dissolving for 20min, circularly stirring by connecting a well cementation cement truck and a ground water pool, adding water into the water pool according to the designed amount, and adding supramolecular polyacrylamide and a stabilizer into the water under the stirring condition to prepare a uniform base liquid, wherein the base liquid accounts for 70%; then preparing a crosslinking solution, wherein the volume of the crosslinking solution is 20% of that of the downhole gel valve, and adding a crosslinking agent into water under the stirring condition to prepare a uniform solution; finally, preparing a gel breaking solution, wherein the volume of the gel breaking solution is 10% of that of the underground gel valve, and adding ammonium persulfate of the gel breaking agent into water under the stirring condition to prepare a uniform solution;
2) And (3) injection process of the gel valve: connecting the cement truck and the high-pressure proportional pump with a tee joint through a pipeline, wherein the outlet end of the tee joint is connected with the working well annulus or an oil pipe; after the pipeline is tested to be qualified, simultaneously mixing the base fluid and the crosslinking fluid by using a cement truck and a high-pressure proportioning pump, continuously injecting the mixture into the underground, then injecting well killing fluid or clear water or slurry, and replacing the mixed solution of the base fluid and the crosslinking fluid to a preset position of a shaft; the injected base fluid and the injected cross-linking fluid form a downhole gel valve with higher viscosity at the temperature of 30-150 ℃ for 20-50min, and the downhole gel valve blocks a well section as long as 130-500 m;
3) When the gel needs to be broken, the gel breaking liquid is injected into the underground gel valve with higher viscosity through the cement truck, and the underground gel valve breaks the gel to form liquid with lower viscosity.
4. The method according to claim 3, wherein in step 1), the dispensing equipment of the jelly glue valve comprises a stirrer, a tank truck and a water pool.
5. The preparation method according to claim 3, wherein in the step 2), the injection equipment of the jelly glue valve comprises a cement truck, a high-pressure proportioning pump, a water tank and a tee joint.
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