WO2019010908A1

WO2019010908A1 - Fluidized mining method of combustible ice through rotary spraying and pressure relief

Info

Publication number: WO2019010908A1
Application number: PCT/CN2017/114451
Authority: WO
Inventors: 许兴亮; 王东杰; 孙大增; 王志明; 田素川; 刘青鑫; 刘忠堂; 宋志坚; 温鹏飞; 李俊生; 马晓健; 俞庆彬
Original assignee: 中国矿业大学
Priority date: 2017-07-14
Filing date: 2017-12-04
Publication date: 2019-01-17
Also published as: CN107288584A; CN107288584B

Abstract

Disclosed is a fluidized mining method of combustible ice through rotary spraying and pressure relief. Situations, such as pressure changes, in a reservoir stratum can be grasped in a timely manner while pressure-relief mining is conducted on combustible ice resources, a corresponding improved treatment is provided, the mining speed can be effectively controlled, and at the same time, information related to the reservoir stratum can be collected, fed back and processed in a timely manner. Meanwhile, the mining method is low in mining cost, easy to implement, high in economic efficiency, simple in mining technology and mature in related application equipment technology, and can also rapidly achieve application in industrial mining.

Description

Combustible ice rotary spray pressure relief fluidization mining method

Technical field

The invention relates to a flammable ice-spinning pressure-removing fluidized mining method, which is suitable for solid-state combustible ice mining in permafrost.

Background technique

Combustible ice is a high-density, high-calorific, clean energy source. According to scientists' estimates, the total amount of global combustible ice resources is converted into methane gas, which is equivalent to two of the world's known total reserves of coal, oil and gas. With the depletion of the world's oil and gas resources, it is extremely urgent to seek new replacement energy sources with huge reserves. According to relevant data analysis, China's South China Sea slope, the southern part of Taiwan Island, the Okinawa Trough and the frozen soil layer of the Qinghai-Tibet Plateau are all subject to the formation of flammable ice. Therefore, carrying out and strengthening research on combustible ice is of great significance for solving China's energy shortage and the world energy crisis.

At present, the main mining methods in each country are as follows: 1. Injecting a heating fluid by direct injection or directly heating the reservoir to increase the temperature in the hydrate region and cause dissolution. The energy consumption is large, and the defects of low heat utilization efficiency cannot be effectively solved. 2. The pressure reduction method reduces the pressure to promote the decomposition of the hydrate. The method does not require continuous excitation, and the cost is low, which is suitable for large-area mining, and is currently the most promising. A development technology; 3, chemical reagent injection mining method, chemical reagent injection mining method by destroying combustible ice by injecting certain chemical reagents such as brine, methanol, ethanol, ethylene glycol, glycerin, etc. into the combustible ice reservoir The phase equilibrium condition of the reservoir promotes the decomposition of combustible ice. Although this method can reduce the initial energy input, the defect is obvious. The chemical reagents required are expensive and have a slow effect on the combustible ice reservoir. 4. Replacement mining method According to the pressure condition of the flammable ice stabilizer zone, under certain temperature conditions, the pressure required to stabilize the flammable ice is higher than that of the CO ₂ hydrate. The heat released by this action can continue the decomposition reaction of the flammable ice. The ground continues, but there are major hidden dangers. If the geological movement releases a large amount of CO2, it will have catastrophic consequences for the ecological environment.

So far, an economical and effective large-scale commercial mining method for flammable ice has not yet been formed. However, it is difficult to achieve a true commercial mining purpose by using only one mining method in the known method. Therefore, new mining methods are urgently needed. Accelerate the large-scale commercial exploitation of combustible ice.

Summary of the invention

The invention provides a flammable ice-spinning pressure-removing fluidized mining method, which can timely grasp the pressure changes in the reservoir, and correspondingly improve the treatment, avoiding the sudden change of reservoir pressure during the mining process and the like, affecting the safety of the hydrate reservoir structure. The danger of sex and stability occurs.

The technical solution adopted by the present invention to solve the technical problem thereof is:

A combustible ice-spinning pressure-removing fluidized mining method comprises the following steps:

The first step: to determine the distribution of the combustible ice reservoir and the thickness of the reservoir;

The second step: dividing the grid unit module of the combustible ice reservoir to form a plurality of mining unit modules;

The third step: laying a mining hole on each mining unit module, the depth of the mining hole from the topsoil layer to the top of the combustible ice reservoir;

The fourth step: using the double pipe column to mine the mining unit module, pre-installing the rotary nozzle at the bottom end of the inner pipe column, installing the sensor at the middle position of the inner wall of the outer pipe column and the bottom end of the inner pipe column;

Step 5: Install the outer tubular string at the center of the mining borehole, the bottom of which is placed in the non-permeable rock formation, and the inner tubular string with the rotary jet nozzle is inserted from the top of the outer tubular string and passes through the bottom of the outer tubular string. Extending into the combustible ice reservoir, a plurality of collecting holes are formed at the top of the outer tubular string, and each collecting hole is connected with a gas pumping chamber disposed on the ground;

Step 6: A water tank is arranged near the bottom of the inner tubular column. The bottom of the water tank is connected with the rotary spray nozzle, and the top of the water tank is opened. The opening is connected with the water tower on the ground through the hose, and the rotary spray nozzle is downward. Rotary jet advancement, the rotary jet nozzle shoots high-speed flammable ice to the surrounding, crushes it, produces gaseous natural gas hydrate, and uses the outer tubular string to transport the generated gaseous natural gas hydrate to the air pump bin for collection until the mining unit module The natural gas hydrates in the collection are all collected;

Step 7: Repeat step 6 until all gas hydrates in other mining unit modules have been collected;

As a further preferred embodiment of the present invention, the diameter of the outer tubular string is the same as the diameter of the mining borehole;

As a further preferred embodiment of the present invention, a support plate is mounted at the bottom end of the outer tubular string for providing support for the inner tubular string;

As a further preferred embodiment of the present invention, the sensor is a pressure sensor and a flow sensor, and the sensor is connected to the signal processor through a wire;

As a further preferred embodiment of the wood invention, a water tank is disposed at a position near the bottom of the inner tubular string, and the depth of the water tank is 1 m.

Through the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

1. The invention can carry out pressure relief mining of combustible ice resources, timely grasp the pressure changes in the reservoir, etc., and provide corresponding improvement treatment to avoid the damage of reservoir structure during the mining process and the safety of the hydrate reservoir structure. The danger of stability occurs;

2. It can effectively realize the exploitation of solid combustible ice;

3. Low mining cost, easy to implement and high economical. The mining technology is simple, the relevant application equipment technology is mature, and the industrial mining application can be quickly controlled to effectively control the mining speed. At the same time, the reservoir related information can be collected and fed back in time.

DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

Figure 1 is a schematic view showing the structure of an apparatus for mining according to a preferred embodiment of the present invention;

Figure 2 is a schematic structural view of an outer tubular string of a preferred embodiment of the present invention;

Figure 3 is a cross-sectional view along line A-A of a preferred embodiment of the present invention.

In the figure: 1 is the mining hole, 2 is the inner pipe column, 3 is the support plate, 4 is the sensor, 5 is the air pump bin, 6 is the water tower, 7 is the annular sealing device, 8 is the outer pipe column, 9 is the rotary jet nozzle 10 is a hose, 11 is a non-permeable rock formation, and 12 is a combustible ice reservoir.

Detailed ways

The invention will now be described in further detail with reference to the drawings. These drawings are simplified schematic diagrams, and only the basic structure of the present invention is illustrated in a schematic manner, and thus only the configurations related to the present invention are shown.

As shown in FIGS. 1-3, the present invention includes the following technical features: a mining bore 1, an inner tubular string 2, a support plate 3, a sensor 4, a gas pump chamber 5, a water tower 6, an annular sealing device 7, and an outer tubular string 8, Rotary spray head 9, hose 10, non-permeable rock formation 11, combustible ice reservoir 12.

The mining principle of the present invention is to apply the "boundary layer surface effect", that is, when the fluid speed is increased, the object is connected to the fluid. The pressure on the interface of the touch will decrease, otherwise the pressure will increase; due to the velocity gradient between the high-speed jet and the solid combustible ice, a pressure drop will occur; the surrounding pressure becomes lower, and the stable balance curve of the combustible ice is continuously destroyed, making the combustible The ice reservoir begins to melt and the gas produced is continuously replenished into the free gas reservoir until the combustible ice is mined.

A flammable ice-spinning pressure-removing fluidized mining method of the present invention comprises the following steps:

Step 5: Install the outer tubular string at the center of the mining borehole, the bottom of which is placed in the non-permeable rock formation, and the inner tubular string with the rotary jet nozzle is inserted from the top of the outer tubular string and passes through the bottom of the outer tubular string. Extend into the combustible ice reservoir and seal with the annular sealing device at the top of the outer tubular string to prevent debris from entering the gap between the inner tubular string and the outer tubular string; a plurality of collecting holes are formed at the top end of the outer tubular string, each collecting hole Connected to a pumping station that is placed on the ground;

Step 6: A water tank is arranged near the bottom of the inner tubular column. The bottom of the water tank is connected with the rotary spray nozzle, and the top of the water tank is opened. The opening is connected with the water tower on the ground through the hose, and the rotary spray nozzle is downward. Rotary jet advancement, the rotary jet nozzle shoots high-speed flammable ice to the surrounding, crushes it, produces gaseous natural gas hydrate, and uses the outer tubular string to transport the generated gaseous natural gas hydrate to the air pump bin for collection until the mining unit module The natural gas hydrates in the collection are all collected; that is, the water pump tank sprays high pressure water into the water tank at the bottom of the inner pipe column through a soft water pipe, forms a high-pressure jet at the rotary spray nozzle, and adjusts the direction of the rotary spray nozzle to produce The cutting plane is horizontal, the rotary nozzle rotates at a high speed, and the disc-shaped high-pressure jet ring ejected by it cuts and breaks the surrounding solid combustible ice, and gradually moves the rotary nozzle downward to the bottom of the combustible ice reservoir to form a radius. Up to 5m of cylindrical mining space, the radius can be adjusted by jet pressure; some gaseous, liquid and if formed during the cutting process The solid state flammable ice is broken. At this time, the gaseous flammable ice is collected. As the free gas decreases, the surrounding pressure becomes lower, and the stable balance curve of the flammable ice is continuously damaged, so that the combustible ice reservoir begins to melt and the gas is continuously added. In a free gas reservoir until the combustible ice is mined;

As a further preferred embodiment of the present invention, a water tank is disposed at a position near the bottom of the inner tubular string, and the depth of the water tank is 1 m.

The invention provides two sensors at different positions, can collect data on the mining surface, and can also monitor the information of the fluid in the collection pipeline to realize simultaneous monitoring of the beginning and the end, and comprehensive gas treatment and utilization on the surface. The reservoir pressure information collected by the signal processor and the analysis and treatment of the injected fluid flow information can timely grasp the decomposition of the hydrate in the reservoir, and adjust the control of the hydrate decomposition gas production. speed.

In the actual mining process, since the mining depth is often several hundred meters or less, or even several kilometers, the inner tubular string design cannot be a common equal-diameter tubular string of several hundred meters, which can generally be designed as a modular installation. That is, every certain length The degree is designed as a section, and the segment and the segment are connected by a connecting structure such as a buckle.

However, this patent uses a high-pressure water jet. When high-pressure water is injected into the pipe string that is open at one end, the high pressure carried by the high-pressure water itself is wasted, and the pressure requirement of forming a high-pressure jet at the nozzle of the jet nozzle cannot be completed. Furthermore, the combustible ice mining is not possible, so the innovative method of the invention adopts the combination of the electric telescopic rod structure and the soft water pipe to solve one problem. Firstly, the hose is made of polyurethane material, ensuring that the water pipe can reach the working water pressure, and then the inside. A 1m deep water tank is set at the bottom of the pipe column, the upper interface is connected with a soft water pipe, and the lower structure is connected with a rotary spray nozzle, so that the speed and pressure of the high pressure jet formed by the rotary jet nozzle can be adjusted by adjusting the water pressure in the ground water tank. The length of the first section of the inner tubular string is greater than 10m of the outer tubular string to ensure the sealing and support between the inner tubular string and the outer tubular string. The inner tubular string adopts an electric telescopic rod structure, and an electric motor is placed on the top of the inner tubular string. The change of the amount of expansion and contraction of the inner pipe string can be accurately realized by controlling the motor.

Those skilled in the art will appreciate that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and unless defined as herein, will not be idealized or overly formal. Explanation.

The meaning of "and/or" as used in the wood application means that the case where each exists alone or both are included.

The term "connected" as used in this application may be a direct connection between components or an indirect connection between components through other components.

In view of the above-described embodiments of the present invention, various changes and modifications may be made by those skilled in the art without departing from the scope of the invention. The technical scope of the present invention is not limited to the contents of the specification, and the technical scope thereof must be determined according to the scope of the claims.

Claims

A flammable ice-spinning pressure-removing fluidized mining method, characterized in that the method comprises the following steps:

The first step: to determine the distribution of the combustible ice reservoir and the thickness of the reservoir;

The second step: dividing the grid unit module of the combustible ice reservoir to form a plurality of mining unit modules;

The third step: laying a mining hole on each mining unit module, the depth of the mining hole from the topsoil layer to the top of the combustible ice reservoir;

The fourth step: using the double pipe column to mine the mining unit module, pre-installing the rotary nozzle at the bottom end of the inner pipe column, installing the sensor at the middle position of the inner wall of the outer pipe column and the bottom end of the inner pipe column;

Step 5: Install the outer tubular string at the center of the mining borehole, the bottom of which is placed in the non-permeable rock formation, and the inner tubular string with the rotary jet nozzle is inserted from the top of the outer tubular string and passes through the bottom of the outer tubular string. Extending into the combustible ice reservoir, a plurality of collecting holes are formed at the top of the outer tubular string, and each collecting hole is connected with a gas pumping chamber disposed on the ground;

Step 6: A water tank is arranged near the bottom of the inner tubular column. The bottom of the water tank is connected with the rotary spray nozzle, and the top of the water tank is opened. The opening is connected with the water tower on the ground through the hose, and the rotary spray nozzle is downward. Rotary jet advancement, the rotary jet nozzle shoots high-speed flammable ice to the surrounding, crushes it, produces gaseous natural gas hydrate, and uses the outer tubular string to transport the generated gaseous natural gas hydrate to the air pump bin for collection until the mining unit module The natural gas hydrates in the collection are all collected;

Step 7: Repeat step 6 until all gas hydrates in other mining unit modules have been collected.
The method of claim 1, wherein the diameter of the outer tubular string is the same as the diameter of the mining borehole.
The method according to claim 1, wherein a support plate is mounted on the bottom end of the outer tubular string for providing support for the inner tubular string.
The method according to claim 1, wherein the sensor is a pressure sensor and a flow sensor, and the sensor is connected to the signal processor through a wire.
The flammable ice-spinning pressure-removing fluidized mining method according to claim 1, characterized in that: a water tank is arranged at a position near the bottom of the inner tubular string, and the depth of the water tank is 1 m.