阅读说明：本技术 一种注气井完井自动注液氮隔热防腐方法 (Automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion ) 是由 栾天 于 2020-07-23 设计创作，主要内容包括：本发明公开了一种注气井完井自动注液氮隔热防腐方法,针对油井注蒸汽的注气井进行特殊完井,在环套空间内注带压液氮,保证在注蒸汽过程中蒸汽所携带的热量最大程度到达油层,同时对带压液氮在环套空间内对注气管柱进行防腐保护,解决了传统注蒸汽热损耗大的问题,也杜绝了氮气进入油层而对地层造成影响,引起气窜的问题。(The invention discloses an automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion, which is used for performing special well completion on a gas injection well for injecting steam into an oil well, injecting liquid nitrogen with pressure into a ring sleeve space, ensuring that heat carried by the steam in the steam injection process reaches an oil layer to the maximum extent, and performing corrosion prevention protection on a gas injection pipe column in the ring sleeve space by using the liquid nitrogen with pressure, thereby solving the problem of large heat loss of the traditional steam injection, and also avoiding the problem of gas channeling caused by the influence of nitrogen entering the oil layer on the stratum.)

1. An automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion is characterized by comprising the following steps:

the center of the gas injection well (1) is provided with a gas injection pipe column (2), and the bottom of the gas injection pipe column (2) is provided with a gas injection tail pipe (6); an annular sleeve space (12) is formed between the outer wall of the gas injection pipe column (2) and the wall of the gas injection well (1);

two stainless steel sealing packers (4) are arranged in the ring sleeve space (12) and above the gas injection layer (3) of the oil well, wherein the two stainless steel sealing packers (4) are arranged up and down and are connected by a stainless steel oil pipe (5);

after the gas injection well (1) is completed, normal-pressure liquid nitrogen is injected into the annular sleeve space (12) through a sleeve valve (14) by using an intelligent liquid nitrogen injection system (10), and the internal and external pressure difference of the gas injection pipe column (2) is kept within the bearing range of the gas injection pipe column (2);

when hot steam (13) is injected into the gas injection pipe column (2), the temperature of the gas injection pipe column (2) is increased rapidly, and liquid nitrogen with pressure is injected into the ring sleeve space (12) through the intelligent liquid nitrogen injection system (10), so that the pressure difference between the inside and the outside of the gas injection pipe column (2) is kept stable.

2. The automatic liquid nitrogen injection, heat insulation and corrosion prevention method for gas injection well completion according to claim 1, wherein the intelligent liquid nitrogen injection system (10) is communicated with a vehicle-mounted liquid nitrogen production device (8), and the vehicle-mounted large-capacity electricity storage cabinet (9) supplies power to the intelligent liquid nitrogen injection system (10) and the vehicle-mounted liquid nitrogen production device (8).

3. The automatic liquid nitrogen injection, heat insulation and corrosion prevention method for gas injection well completion according to claim 1, characterized in that a stainless steel oil pipe is adopted as the gas injection tail pipe (6).

Technical Field

The invention relates to the technical field of oil extraction, in particular to an automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion.

Background

In order to increase the crude oil yield and drive the thick oil super-thick oil, each large oil field generally adopts a mode of injecting steam into an oil layer to extract oil. In order to reduce the heat loss of hot steam in the gas injection pipe column and reduce the energy consumption, a heat insulation pipe and a nitrogen gas concomitant injection mode are generally adopted in the process of injecting steam. But the mode that adopts the thermal-insulated pipe gas injection can cause serious corruption to hang weight very big, have great limitation, the mode of nitrogen gas companion injection all can bring very big influence to the stratum moreover, can destroy the stratum structure behind a large amount of nitrogen gas entering stratum, causes serious gas channeling, seriously influences the effect of annotating steam.

The heat loss in the steam injection process is huge, more than 50% of heat is lost in the pipe column, and huge waste of energy is caused.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion, which is used for performing special well completion on a gas injection well for injecting steam into an oil well, injecting liquid nitrogen with pressure into a ring sleeve space, ensuring that heat carried by the steam in the steam injection process reaches an oil layer to the maximum extent, and performing corrosion prevention protection on a gas injection pipe column in the ring sleeve space by using the liquid nitrogen with pressure, thereby solving the problem of large heat loss of the traditional steam injection, and also avoiding the problem of gas channeling caused by the influence of the nitrogen entering the oil layer on the stratum.

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

an automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion specifically comprises the following steps:

a gas injection pipe column is arranged in the center of the gas injection well, and a gas injection tail pipe is arranged at the bottom of the gas injection pipe column; an annular sleeve space is formed between the outer wall of the gas injection pipe column and the wall of the gas injection well;

two stainless steel sealing packers are arranged in the ring sleeve space and above the gas injection layer of the oil well, are vertically arranged and are connected by adopting stainless steel oil pipes;

after the gas injection well is completed, normal-pressure liquid nitrogen is injected into the annular sleeve space through a sleeve valve by using an intelligent liquid nitrogen injection system, and the internal and external pressure difference of the gas injection pipe column is kept within the bearing range of the gas injection pipe column;

when hot steam is injected into the gas injection pipe column, the temperature of the gas injection pipe column is increased sharply, and liquid nitrogen with pressure is injected into the annular sleeve space through the intelligent liquid nitrogen injection system, so that the pressure difference between the inside and the outside of the gas injection pipe column is kept stable.

Furthermore, the intelligent liquid nitrogen injection system is communicated with a vehicle-mounted liquid nitrogen making device, and the vehicle-mounted large-capacity electricity storage cabinet supplies power to the intelligent liquid nitrogen injection system and the vehicle-mounted liquid nitrogen making device.

Further, the gas injection tail pipe adopts a stainless steel oil pipe.

The invention has the beneficial effects that:

1. the method is characterized in that a special well completion is carried out on a gas injection well for injecting steam into an oil well, liquid nitrogen with pressure is injected into a ring sleeve space, and nitrogen belongs to sub-inert gas and is insensitive to heat conduction, so that heat carried by steam in the steam injection process can be guaranteed to reach an oil layer to the maximum extent, and the problem of large heat loss of the traditional steam injection process is solved; meanwhile, the pressurized liquid nitrogen isolates oxygen and carbon dioxide in the ring sleeve space, so that the chemical corrosion and the electric corrosion of the oxygen and the carbon dioxide to the gas injection pipe column are blocked, and the effect of performing anticorrosion protection on the gas injection pipe column is achieved.

2. According to the invention, the stainless steel sealing packer is arranged in the ring sleeve space and above the gas injection layer of the oil well, so that the problem of gas channeling caused by the influence of nitrogen entering an oil layer on the stratum can be effectively solved.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention.

Detailed Description

The invention will be further described with reference to the accompanying drawings. It should be noted that the present embodiment is premised on the technical solution, and detailed description and specific implementation are given, but the scope of protection of the present invention is not limited to the present embodiment.

The embodiment provides an automatic liquid nitrogen injection heat insulation and corrosion prevention method for gas injection well completion, as shown in fig. 1, specifically comprising the following steps:

the center of the gas injection well 1 is provided with a gas injection pipe column 2, and the bottom of the gas injection pipe column 2 is provided with a gas injection tail pipe 6; an annular sleeve space 12 is formed between the outer wall of the gas injection pipe column 2 and the wall of the gas injection well 1;

a stainless steel sealing packer 4 is arranged in the ring sleeve space 12 and above the oil well gas injection layer 3;

after the gas injection well 1 is completed, normal-pressure liquid nitrogen is injected into the ring sleeve space 12 through the sleeve valve 14 by using the intelligent liquid nitrogen injection system 10, and the internal and external pressure difference of the gas injection pipe column 2 is kept within the bearing range of the gas injection pipe column 2;

when hot steam 13 is injected into the gas injection pipe column 2, the temperature of the gas injection pipe column 2 is increased sharply, and liquid nitrogen with pressure is injected into the ring sleeve space 12 through the intelligent liquid nitrogen injection system 10, so that the pressure difference between the inside and the outside of the gas injection pipe column 2 is kept stable.

In this embodiment, the intelligent liquid nitrogen injection system 10 is connected to the vehicle-mounted liquid nitrogen making device 8, and the vehicle-mounted large-capacity electricity storage cabinet 9 supplies power to the intelligent liquid nitrogen injection system 10 and the vehicle-mounted liquid nitrogen making device 8.

In the present embodiment, the gas injection tail pipe 6 is made of a stainless steel oil pipe.

In the embodiment, the gas injection pipe column 2 adopts a traditional oil pipe.

It should be noted that the intelligent liquid nitrogen injection system 10 can supplement pressurized liquid nitrogen at any time according to the pressure in the annular space 12, so as to keep the internal and external pressure difference of the gas injection pipe column 2 stable.

In this embodiment, two stainless steel seal packers 4 are installed at positions above the gas injection horizon 3 of the oil well, and the two stainless steel seal packers 4 are arranged up and down and connected by a stainless steel oil pipe 5.

Various other changes and modifications to the above-described embodiments and concepts will become apparent to those skilled in the art from the above description, and all such changes and modifications are intended to be included within the scope of the present invention as defined in the appended claims.