CN112592704B

CN112592704B - High-temperature-resistant hydrate inhibitor and preparation method thereof

Info

Publication number: CN112592704B
Application number: CN202011605862.9A
Authority: CN
Inventors: 鲍素领; 邰津; 吴振华; 吴丹
Original assignee: Tianjin Xinxiang Petroleum Technology Co ltd
Current assignee: Tianjin Xinxiang Petroleum Technology Co ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-09-20
Anticipated expiration: 2040-12-30
Also published as: CN112592704A

Abstract

The invention provides a high-temperature-resistant hydrate inhibitor, a preparation method and application thereofThe problems that the low-dosage hydrate inhibitor in the prior art is degraded and loses efficacy at the temperature of more than 110 ℃ and is difficult to inject due to high viscosity are solved. The inhibitor comprises 40-45% by mass of polypropylene glycol-bis-2-aminopropyl ether; 1% -3% of a synergist; 0.3% -0.4% of PAAS; span-80, 0.1% -0.2%; 0.4 to 0.5 percent of isopropanol; 50.9 to 58.2 percent of water. The inhibitor main agent is a small molecular weight product synthesized at high temperature, the product is low in viscosity and temperature resistant, ether bonds and amino groups in molecules are easy to form hydrogen bonds with water molecules, and the hydrate inhibitor has an excellent hydrate inhibition effect; the synergist is used for capturing CO in natural gas ₂ 、H ₂ S, the water molecule cage structure is disturbed, the nucleation time of the hydrate can be obviously prolonged, the hydrate inhibition effect of the product is obviously improved, and the dosage of the inhibitor is reduced.

Description

High-temperature-resistant hydrate inhibitor and preparation method thereof

Technical Field

The invention belongs to the field of petroleum and natural gas exploitation and gathering and transportation, and particularly relates to a high-temperature-resistant hydrate inhibitor and a preparation method thereof.

Background

In a low-temperature high-pressure pipeline in the natural gas exploitation process, small molecule gas and liquid water easily form ice and snow-like cage crystals, namely natural gas hydrate.

After the natural gas hydrate is formed, a shaft, a pipeline, a valve and various equipment are blocked, and great harm is brought to the exploitation, gathering and transportation and processing of the natural gas, so that the natural gas hydrate inhibitor needs to be injected. Hydrate inhibitors are divided into thermodynamic inhibitors (methanol, ethylene glycol and the like) and low-dosage hydrate inhibitors, and the low-dosage hydrate inhibitors are more and more favored by researchers and oil and gas field users because of safety, environmental protection, low dosage and low comprehensive cost.

There are three current techniques for injecting low doses of hydrate inhibitors:

1. hydrate is formed in a shaft, and continuous filling or periodic filling is carried out by adopting a sleeve;

2. the hydrate is formed in a ground gathering and transportation pipeline, and continuous filling, periodic filling or continuous filling on the ground is adopted;

3. hydrates are formed in the well bore and the surface pipeline simultaneously, and continuous filling or periodic filling is carried out by adopting a sleeve.

Casing injection is a common injection mode of low-dose hydrate inhibitors, because the inhibitors can be extracted from an oil pipe only after entering the casing through a high-temperature environment at the bottom of the well, the hydrate inhibitors are required to resist the temperature at the bottom of the well, and for wells with the well depth of more than 4000m, the inhibitors must resist the high-temperature environment.

Common low-dose hydrate inhibitors in the prior art include polyvinylpyrrolidone PVP, polycaprolactone PCL, and Luvicap developed by basf, and some polymers and compounds derived therefrom. The inhibitor is not good in high temperature resistance, degradation failure of the inhibitor can be caused in a high-temperature environment for a well with the temperature of more than 110 ℃, meanwhile, the hydrate inhibitor is a high molecular weight polymer, the viscosity is high in a low-temperature environment, injection is difficult in winter construction, the hydrate inhibitor can be injected by heating to reduce the viscosity on site, and site construction is not convenient.

Disclosure of Invention

In view of the defects or shortcomings in the prior art, the invention aims to provide a high-temperature-resistant hydrate inhibitor and a preparation method thereof, wherein the hydrate inhibitor is high-temperature-resistant, keeps an inhibiting effect in a gas production well with a well depth of more than 4000 meters and a well bottom temperature of more than 110 ℃, has low viscosity at low temperature, can be injected smoothly in a low-temperature environment, and has small using amount and remarkable inhibiting effect; the preparation method has the advantages of simple process, easily obtained raw materials and reduced oil and gas exploitation cost.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

in a first aspect, an embodiment of the present invention provides a high temperature resistant hydrate inhibitor, where the hydrate inhibitor includes, by mass:

wherein the average molecular weight of the polypropylene glycol-bis-2-aminopropyl ether is 200-300.

As a preferred embodiment of the present invention, the synergist comprises: one or more of unsaturated organic amine diethylenetriamine, triethylene tetramine and tetraethylene pentamine.

As a preferred embodiment of the invention, the high-temperature-resistant hydrate inhibitor is suitable for gas recovery wells with the well depth of more than 4000 meters and the bottom temperature of more than 110 ℃, and the hydrate inhibitor is filled from a casing to inhibit the formation of well bore hydrates.

In a second aspect, the embodiment of the present invention further provides a preparation method of the high temperature resistant hydrate inhibitor, where the preparation method includes the following steps:

step S1, taking the total mass of the inhibitor as a reference, adding 52.5-58.7% of water, 0.1-0.2% of span-80 and 0.4-0.5% of isopropanol into a reaction kettle, and stirring for 30 minutes;

step S2, adding 0.3-0.4% of PAAS into a reaction kettle and stirring for 20 minutes;

step S3, adding 1-3% of synergist into a reaction kettle and stirring for 20 minutes;

step S4, heating 40-45% of polypropylene glycol-bis-2-aminopropyl ether reaction kettle with the average molecular weight of 200-300 to 140 ℃, stirring for reaction for 2-3 hours, and cooling to room temperature to obtain the high temperature resistant hydrate inhibitor.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

(1) the polypropylene glycol-bis-2-aminopropyl ether used as a main agent in the inhibitor has the advantages of average molecular weight of 200-300, small molecular weight, low viscosity and convenient injection; ether bonds and amino groups in the inhibitor form hydrogen bonds with water molecules to inhibit the formation of hydrates, thereby improving the inhibition effect and reducing the dosage of the inhibitor;

(2) the synergist diethylenetriamine, triethylene tetramine, tetraethylene pentamine and other small molecular unsaturated organic amines capture carbon dioxide and hydrogen sulfide in natural gas by utilizing the unique self structure and performance of the synergist, play a role in disturbing and destroying the water molecular cage structure, remarkably prolong the nucleation time of hydrate, increase the response time of on-site hydrate formation, remarkably improve the hydrate inhibition effect of the product, and greatly reduce the dosage of the inhibitor;

(3) the main component of the inhibitor is polypropylene glycol-bis-2-aminopropyl ether with the average molecular weight of 200-300, and the inhibitor is a low-molecular-weight product synthesized at high temperature, so that the inhibitor has a more stable structure in a high-temperature well, prevents degradation at the bottom of the high-temperature well, and is a hydrate inhibitor with low viscosity and high temperature resistance of 110-150 ℃;

(4) the preparation method of the inhibitor has the advantages of easily obtained raw materials, simple preparation process and reduced oil and gas exploitation cost.

Detailed Description

The present invention will be described in further detail with reference to specific examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail by examples.

Example 1

The embodiment provides a high-temperature-resistant hydrate inhibitor and a preparation method thereof, wherein the inhibitor comprises the following components in percentage by mass:

45% of polypropylene glycol-bis-2-aminopropyl ether with the average molecular weight of 200-300;

tetraethylenepentamine, 3%;

PAAS，0.4％；

span-80, 0.2%;

isopropanol, 0.5%;

50.9 percent of water.

In the proportion, the high-temperature-resistant PAAS has better compatibility with high-salinity brine, and is matched with the polypropylene glycol-bis-2-aminopropyl ether to realize the inhibiting effect on the hydrate at high temperature.

The preparation process of the inhibitor is as follows:

firstly, adding 50.9% of water, 0.2% of span-80 and 0.5% of isopropanol into a reaction kettle, and stirring for 30 minutes; then adding 0.4 percent of PAAS into the reaction kettle and stirring for 20 minutes; adding 3% of tetraethylenepentamine into the reaction kettle again, and stirring for 20 minutes;

and finally, heating 45% of polypropylene glycol-bis-2-aminopropyl ether reaction kettle with the average molecular weight of 200-300 to 140 ℃, stirring for reaction for 2-3 hours, and cooling to the normal temperature to obtain the uniform high-temperature-resistant low-viscosity hydrate inhibitor W1.

Example 2

40% of polypropylene glycol-bis-2-aminopropyl ether with the average molecular weight of 200-300;

1% of diethylenetriamine;

PAAS，0.3％；

span-80, 0.1%;

isopropanol, 0.4%;

58.2 percent of water.

The preparation process of the inhibitor is as follows:

firstly, adding 58.2 percent of water, 0.1 percent of span-80 and 0.4 percent of isopropanol into a reaction kettle, and stirring for 30 minutes; then adding 0.3 percent of PAAS into the reaction kettle and stirring for 20 minutes; adding 1% of diethylenetriamine into the reaction kettle again and stirring for 20 minutes;

and finally, heating 40% of polypropylene glycol-bis-2-aminopropyl ether reaction kettle with the average molecular weight of 200-300 to 140 ℃, stirring for reaction for 2-3 hours, and cooling to the normal temperature to obtain the uniform high-temperature-resistant low-viscosity hydrate inhibitor W2.

Example 3

42% of polypropylene glycol-bis-2-aminopropyl ether with the average molecular weight of 200-300;

1% of diethylenetriamine, 1% of triethylene tetramine and 1% of tetraethylenepentamine;

PAAS，0.35％；

span-80, 0.15%;

isopropanol, 0.45%;

water, 54.05%.

The preparation process of the inhibitor is as follows:

firstly, 42 percent of water, 0.15 percent of span-80 and 0.45 percent of isopropanol are added into a reaction kettle and stirred for 30 minutes; then adding 0.35% of PAAS into the reaction kettle and stirring for 20 minutes; adding 1% of the mixture of diethylenetriamine, triethylene tetramine and tetraethylene pentamine into the reaction kettle again and stirring for 20 minutes;

and finally, heating 42% of polypropylene glycol-bis-2-aminopropyl ether reaction kettle with the average molecular weight of 200-300 to 140 ℃, stirring for reaction for 2-3 hours, and cooling to the normal temperature to obtain the uniform high-temperature-resistant low-viscosity hydrate inhibitor W3.

The hydrate inhibitors W1, W2 and W3 provided by the embodiment of the invention are applied to the field of Jilin oil field in the depth of 303-4 wells, and the depth of the drilled well in the depth of 303-4 wells is 4315 meters. 4064- ⁴ m ³ Daily liquid production of 1m ³ The oil pressure is 5MPa, the pressure after interception is 3.2MPa, and the temperature is 2 ℃.

Analysis of a natural gas component sample of 303-4 inch deep wells revealed that the methane content was 79.02%, the ethane content was 8.23%, the propane content was 2.64%, the nitrogen content was 4.59%, the carbon dioxide was 2.91%, and the relative density of natural gas was 0.7.

The hydrate inhibitor adopts a casing periodic pumping mode, the dosing concentration is 0.5 percent, the continuous production does not occur freezing and blocking, and the product application effect is good. A thermodynamic inhibitor methanol is adopted in the prior art, the dosing concentration is 40%, and compared with the use of methanol, the cost is saved by 1/3-1/4.

The inhibitory effects of the inhibitors in the above three examples at different supercooling degrees are shown in table 1.

TABLE 1

As shown in Table 1, the effect of the high-temperature-resistant hydrate inhibitor on inhibiting the hydrate is more than 60min under different supercooling degrees, and safe gathering and transportation can be realized from the production ground to a united station for a gas production well.

Meanwhile, inhibitors W1, W2 and W3, PVP products, PCL products and Luvicap in the prior art were aged under the same conditions (temperature and time), the appearance of the products was observed, and the hydrate inhibitor effect evaluation test was performed on the aged products under the experimental conditions of 5MPa of pressure, 2 ℃ of temperature, 250rps of rotation speed and 5 ten thousand of mineralization, and the post-aging phenomenon and the time for inhibiting the formation of hydrates were listed in table 2.

TABLE 2

As can be seen from Table 2, the high-temperature-resistant hydrate inhibitor provided by the embodiment of the invention can still keep a good inhibiting effect in a high-temperature environment of 110-150 ℃, and does not generate a turbid phenomenon and hydrate.

In the comparative example, the product can basically keep good transparency and excellent hydrate inhibition effect at a low temperature of 50 ℃, but after aging at a high temperature of 110 ℃, the product becomes turbid, and the hydrate inhibition effect is completely lost.

The foregoing description is only exemplary of the preferred embodiments of the invention and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention herein disclosed is not limited to the particular combination of features described above, but also encompasses other arrangements formed by any combination of the above features or their equivalents without departing from the spirit of the invention. For example, the above features and (but not limited to) features having similar functions disclosed in the present invention are mutually replaced to form the technical solution.

Claims

1. A high-temperature-resistant hydrate inhibitor is characterized by comprising the following components in percentage by mass:

40 to 45 percent of polypropylene glycol-bis-2-aminopropyl ether;

1 to 3 percent of synergist;

PAAS 0.3%～0.4%；

span-800.1% -0.2%;

0.4 to 0.5 percent of isopropanol;

50.9 to 58.2 percent of water;

wherein the average molecular weight of the polypropylene glycol-bis-2-aminopropyl ether is 200-300; the synergist comprises: one or more of unsaturated organic amine diethylenetriamine, triethylene tetramine and tetraethylene pentamine.

2. The high temperature resistant hydrate inhibitor according to claim 1, wherein the high temperature resistant hydrate inhibitor is suitable for gas recovery wells with a well depth of more than 4000 meters and a bottom temperature of more than 110 ℃, and hydrate inhibitor is injected from a casing to inhibit formation of wellbore hydrate.

3. A process for the preparation of a refractory hydrate inhibitor according to claim 1 or claim 2, comprising the steps of:

step S1, based on the total mass of the inhibitor, adding 50.9-58.2% of water, 0.1-0.2% of span-80 and 0.4-0.5% of isopropanol into a reaction kettle, and stirring for 30 minutes;