阅读说明：本技术 一种地热井可降解胶塞液及利用可降解胶塞液封层的方法 (Geothermal well degradable rubber plug liquid and method for sealing layer by utilizing degradable rubber plug liquid ) 是由 周涛 范旭良 宋江莉 王磊 周小勤 王静 彭兰贞 陈丽娟 于 2021-09-11 设计创作，主要内容包括：本发明公开了一种地热井可降解胶塞液及利用可降解胶塞液封层的方法,该胶塞液包含以下重量份的原料：异佛尔酮二异氰酸酯40份、聚己内酯多元醇100份,2,2-二羟甲基丙酸4份,丁二醇5份,三乙胺3份,乙二胺2份,蒸馏水1300份、丙烯酰胺100-150份、过硫酸铵1份、N,N-亚甲基双丙烯酰胺1份。该胶塞液与井筒具有较好的粘接强度,可满足封层需要。固化后的胶塞可在双氧水溶液的作用下发生破胶。(The invention discloses a geothermal well degradable rubber plug liquid and a method for sealing a layer by utilizing the degradable rubber plug liquid, wherein the rubber plug liquid comprises the following raw materials in parts by weight: 40 parts of isophorone diisocyanate, 100 parts of polycaprolactone polyol, 4 parts of 2, 2-dimethylolpropionic acid, 5 parts of butanediol, 3 parts of triethylamine, 2 parts of ethylenediamine, 1300 parts of distilled water, 100 parts of acrylamide, 150 parts of ammonium persulfate and 1 part of N, N-methylene bisacrylamide. The rubber plug liquid has better bonding strength with a shaft, and can meet the requirement of a sealing layer. The solidified rubber plug can be broken under the action of the hydrogen peroxide solution.)

1. The geothermal well degradable rubber plug liquid is characterized by comprising the following raw materials in parts by weight: 40 parts of isophorone diisocyanate, 100 parts of polycaprolactone polyol, 4 parts of 2, 2-dimethylolpropionic acid, 5 parts of butanediol, 3 parts of triethylamine, 2 parts of ethylenediamine, 1300 parts of distilled water, 100 parts of acrylamide-containing material 150 parts, 1 part of ammonium persulfate and 1 part of N, N-methylene bisacrylamide.

2. The geothermal well degradable plug fluid of claim 1, wherein the average molecular weight of the polycaprolactone is 1800-.

3. A method for preparing the geothermal well degradable rubber plug liquid in the claim 1, which is characterized by comprising the following steps:

(1) adding 100 parts of polycaprolactone polyol into a reaction kettle in parts by weight, heating to 75 ℃, and preserving heat for 0.5 h;

further heating the reaction system to 110 ℃, vacuumizing and dehydrating for 0.5h under 250Pa, and then cooling to 65 ℃;

(2) adding 4 parts of 2, 2-dimethylolpropionic acid, 5 parts of butanediol and 40 parts of isophorone diisocyanate into a reaction kettle under the condition of stirring, heating the temperature of a reaction system to 80 ℃, and reacting for 5 hours;

(3) cooling the temperature of the reaction system to 50 ℃, adding 3 parts of triethylamine, and reacting for 0.5 h; then adding 300 parts of distilled water and 2 parts of ethylenediamine into the system, continuously stirring for reacting for 2 hours, and cooling the reaction system to 25 ℃;

(4) adding 1000 parts of distilled water, 100 parts of acrylamide, 150 parts of ammonium persulfate, 1 part of N, N-methylene bisacrylamide and 1 part of ammonium persulfate into the system, continuing stirring for 0.1h, and stopping stirring to obtain the geothermal well degradable rubber plug liquid.

4. A method for liquid sealing a layer by utilizing a degradable rubber plug is characterized by comprising the following steps:

(1) after the oil pipe is lowered to a target layer, 100L-200L of degradable rubber plug liquid is pumped into the shaft from the oil pipe, and the degradable rubber plug liquid is replaced to the target layer by clear water, wherein the temperature of the target layer is 90-110 ℃;

(2) lifting the oil pipe to separate and contact the oil pipe and the degradable rubber plug liquid, and curing and molding the degradable rubber plug liquid after 4 hours to finish plugging;

(3) after the construction is finished, an oil pipe is put into the shaft to a position 0.5m above the rubber plug, 15% hydrogen peroxide aqueous solution is pumped to the position of the rubber plug through the oil pipe for rubber breaking, after the rubber plug is degraded, clear water is injected from the oil pipe, and degradation products are washed out of the shaft.

Technical Field

The invention relates to a geothermal well degradable rubber plug liquid and a method for sealing a layer by utilizing the degradable rubber plug liquid.

Background

In well repair and fracturing operations, because the formation pressure and the internal pressure of a shaft are not balanced, a target layer position needs to be plugged. The liquid rubber plug can realize the plugging of a target layer, and can break rubber and discharge out of a shaft after the construction is finished, so that the liquid rubber plug is widely concerned. The existing liquid rubber plug mainly aims at the field of oil and gas wells, and is hydrogel in nature. The hydrogel system is formed by mainly using guar gum, polyacrylamide and other substances as polymer matrixes through crosslinking. The liquid rubber plug has the problem that the wall-grabbing force of the rubber plug is not strong. The oil-gas wells mostly contain a large amount of combustible and explosive substances such as crude oil, natural gas and the like, so that the selection of the gel-forming substance and the corresponding gel breaker is limited to a certain extent in the design process of the rubber plugs.

Disclosure of Invention

The invention aims to provide a geothermal well degradable rubber plug liquid, so that a cured rubber plug has good plugging capability, and can be quickly broken in a short time and discharged out of a shaft. Therefore, the technical scheme of the invention is as follows: the geothermal well degradable rubber plug liquid comprises the following raw materials in parts by weight: 40 parts of isophorone diisocyanate, 100 parts of polycaprolactone polyol, 4 parts of 2, 2-dimethylolpropionic acid, 5 parts of butanediol, 3 parts of triethylamine, 2 parts of ethylenediamine, 1300 parts of distilled water, 100 parts of acrylamide and 150 parts of ammonium persulfate and 1 part of N, N-methylenebisacrylamide.

The average molecular weight of the polycaprolactone was 1800-.

The invention also provides a preparation method of the oil and gas well plugging fluid, which comprises the following steps:

(1) adding 100 parts of polycaprolactone polyol into a reaction kettle in parts by weight, heating to 75 ℃, and preserving heat for 0.5 h. Further heating the reaction system to 110 ℃, vacuumizing and dehydrating for 0.5h under 250Pa, and then cooling to 65 ℃;

(2) adding 4 parts of 2, 2-dimethylolpropionic acid, 5 parts of butanediol and 40 parts of isophorone diisocyanate into a reaction kettle under the condition of stirring, heating the temperature of a reaction system to 80 ℃, and reacting for 5 hours;

(3) and cooling the temperature of the reaction system to 50 ℃, adding 3 parts of triethylamine, and reacting for 0.5 h. Then adding 300 parts of distilled water and 2 parts of ethylenediamine into the system, continuously stirring for reacting for 2 hours, and cooling the reaction system to 25 ℃;

(4) adding 1000 parts of distilled water, 100 parts of acrylamide, 150 parts of ammonium persulfate, 1 part of N, N-methylene bisacrylamide and 1 part of ammonium persulfate into the reaction system, continuing stirring for 0.1h, and stopping stirring to obtain the degradable rubber plug liquid for the geothermal well.

The invention has the beneficial effects that: the invention introduces the polyester urethane material into the polyacrylamide hydrogel to form an interpenetrating network structure, thereby greatly enhancing the mechanical strength of the formed polymer gel. The invention is suitable for the temperature range of a target layer of 90-110 ℃, and the rubber plug liquid can rapidly generate polymerization reaction in a shaft to form hydrogel. Acrylamide after polymerization can restrict water molecules which originally move freely in the system, and at the moment, polyurethane molecules can show excellent bonding performance, so that the bonding strength of the rubber plug and a shaft is greatly improved, and the rubber plug is endowed with good pressure bearing performance. Meanwhile, polyester polyurethane molecules contain a large number of ester bonds which are easy to degrade, the degradation performance of the polyester polyurethane molecules is far superior to that of polyether polyurethane, and the polyester polyurethane can be degraded under the action of hydrogen peroxide at a target stratum temperature. The polyacrylamide molecules in the rubber plug can also be subjected to macromolecular chain fracture under the action of hydrogen peroxide, so that the rubber plug is endowed with degradable performance.

The invention also provides a method for sealing a layer by using the degradable rubber plug liquid, which comprises the following steps:

(1) after the oil pipe is lowered to a target layer, 100L-200L of degradable rubber plug liquid is pumped into the shaft from the oil pipe, and the degradable rubber plug liquid is replaced to the target layer by clear water, wherein the temperature of the target layer is 90-110 ℃;

(2) lifting the oil pipe to separate and contact the oil pipe and the degradable rubber plug liquid, and curing and molding the degradable rubber plug liquid after 4 hours to finish plugging; (3) after the construction is finished, an oil pipe is put into the shaft to a position 0.5m above the rubber plug, and the hydrogen peroxide aqueous solution with the concentration of 15% is pumped to the position of the rubber plug through the oil pipe for rubber breaking. After the rubber plug is degraded, clear water is injected from the oil pipe, and degradation products are washed out of the shaft.

Detailed Description

The invention is described in further detail below:

example 1

Weighing the following raw materials in parts by weight: 40kg of isophorone diisocyanate, 100kg of polycaprolactone polyol (with the average molecular weight of 1800), 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol, 3kg of triethylamine, 2kg of ethylenediamine, 1300kg of distilled water, 100kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylenebisacrylamide.

The preparation method comprises the following steps:

(1) adding 100kg of polycaprolactone polyol into a reaction kettle, heating to 75 ℃, and preserving heat for 0.5 h. Further heating the reaction system to 110 ℃, vacuumizing and dehydrating for 0.5h under 250Pa, and then cooling to 65 ℃;

(2) adding 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol and 40kg of isophorone diisocyanate into a reaction kettle under the condition of stirring, heating the temperature of a reaction system to 80 ℃, and reacting for 5 hours;

(3) the temperature of the reaction system is reduced to 50 ℃, and then 3kg of triethylamine is added to react for 0.5 h. Then adding 300kg of distilled water and 2kg of ethylenediamine into the system, continuously stirring for reacting for 2 hours, and cooling the reaction system to 25 ℃;

(4) adding 1000kg of distilled water, 100kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylene bisacrylamide into the reaction system, continuing stirring for 0.1h, and stopping stirring to obtain the degradable rubber plug liquid for the geothermal well.

A method for liquid sealing a layer by utilizing a degradable rubber plug comprises the following steps:

(1) after the oil pipe is lowered to a target layer, 100L of degradable rubber plug liquid is pumped into the shaft from the oil pipe, and the degradable rubber plug liquid is replaced to the target layer by clear water, wherein the temperature of the target layer is 90 ℃;

(2) lifting the oil pipe to separate and contact the oil pipe and the degradable rubber plug liquid, and curing and molding the degradable rubber plug liquid after 4 hours to finish plugging;

(3) after the construction is finished, an oil pipe is put into the shaft to a position 0.5m above the rubber plug, and the hydrogen peroxide aqueous solution with the concentration of 15% is pumped to the position of the rubber plug through the oil pipe for rubber breaking. After the rubber plug is degraded, clear water is injected from the oil pipe, and degradation products are washed out of the shaft.

Example 2

Weighing the following raw materials in parts by weight: 40kg of isophorone diisocyanate, 100kg of polycaprolactone polyol (average molecular weight of 1900), 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol, 3kg of triethylamine, 2kg of ethylenediamine, 1300kg of distilled water, 100kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylenebisacrylamide.

The preparation method comprises the following steps:

(1) adding 100kg of polycaprolactone polyol into a reaction kettle, heating to 75 ℃, and preserving heat for 30 min. Further heating the reaction system to 110 ℃, vacuumizing and dehydrating for 30min under 250Pa, and then cooling to 65 ℃;

(2) adding 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol and 40kg of isophorone diisocyanate into a reaction kettle under the stirring condition, heating the temperature of a reaction system to 80 ℃, and reacting for 5 hours;

(3) and (3) cooling the temperature of the reaction system to 50 ℃, adding 3kg of triethylamine, and reacting for 20 min. Then adding 300kg of distilled water and 2kg of ethylenediamine into the system, continuously stirring for reacting for 2 hours, and cooling the reaction system to 25 ℃;

(4) 1000kg of distilled water, 125kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylene bisacrylamide are added into the system, the stirring is continued for 0.1 hour, and the stirring is stopped to obtain the degradable rubber plug liquid for the geothermal well.

A method for liquid sealing a layer by utilizing a degradable rubber plug comprises the following steps:

(1) after the oil pipe is lowered to a target layer, 150L of degradable rubber plug liquid is pumped into the shaft from the oil pipe, and the degradable rubber plug liquid is replaced to the target layer by clear water, wherein the temperature of the target layer is 100 ℃;

(2) lifting the oil pipe to separate and contact the oil pipe and the degradable rubber plug liquid, and curing and molding the degradable rubber plug liquid after 4 hours to finish plugging;

(3) after the construction is finished, an oil pipe is put into the shaft to a position 0.5m above the rubber plug, and the hydrogen peroxide aqueous solution with the concentration of 15% is pumped to the position of the rubber plug through the oil pipe for rubber breaking. After the rubber plug is degraded, clear water is injected from the oil pipe, and degradation products are washed out of the shaft.

Example 3

Weighing the following raw materials in parts by weight: 40kg of isophorone diisocyanate, 100kg of polycaprolactone polyol (average molecular weight of 2000), 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol, 3kg of triethylamine, 2kg of ethylenediamine, 1300kg of distilled water, 150kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylene-bisacrylamide.

The preparation method comprises the following steps:

(1) adding 100kg of polycaprolactone polyol into a reaction kettle, heating to 75 ℃, and preserving heat for 30 min. Further heating the reaction system to 110 ℃, vacuumizing and dehydrating for 30min under 250Pa, and then cooling to 65 ℃;

(2) adding 4 kg of 2, 2-dimethylolpropionic acid, 5kg of butanediol and 40kg of isophorone diisocyanate into a reaction kettle under the stirring condition, heating the temperature of a reaction system to 80 ℃, and reacting for 5 hours;

(3) the temperature of the reaction system is reduced to 50 ℃, and then 3kg of triethylamine is added to react for 20 min. Then adding 300kg of distilled water and 2kg of ethylenediamine into the system, continuously stirring for reacting for 2 hours, and cooling the reaction system to 25 ℃;

(4) adding 1000kg of distilled water, 150kg of acrylamide, 1kg of ammonium persulfate and 1kg of N, N-methylene bisacrylamide into the reaction system, continuing stirring for 0.1h, and stopping stirring to obtain the degradable rubber plug liquid for the geothermal well.

A method for liquid sealing a layer by utilizing a degradable rubber plug comprises the following steps:

(1) after the oil pipe is lowered to a target layer, 200L of degradable rubber plug liquid is pumped into the shaft from the oil pipe, and the degradable rubber plug liquid is replaced to the target layer by clear water, wherein the temperature of the target layer is 110 ℃;

(2) lifting the oil pipe to separate and contact the oil pipe and the degradable rubber plug liquid, and curing and molding the degradable rubber plug liquid after 4 hours to finish plugging;

(3) after the construction is finished, an oil pipe is put into the shaft to a position 0.5m above the rubber plug, and the hydrogen peroxide aqueous solution with the concentration of 15% is pumped to the position of the rubber plug through the oil pipe for rubber breaking. After the rubber plug is degraded, clear water is injected from the oil pipe, and degradation products are washed out of the shaft.