阅读说明：本技术 海域天然气水合物的原位种植和采集系统及其方法 (In-situ planting and collecting system and method for sea natural gas hydrate ) 是由 孙治雷 吴能友 张喜林 曹红 耿威 王利波 翟滨 张现荣 徐翠玲 于 2019-08-27 设计创作，主要内容包括：本发明所述的海域天然气水合物的原位种植和采集系统及其方法,提供一种原位井扩孔、截留并种植天然气水合物以实施后续采集的系统及其方法。以期加速提高泄漏区羽状流气体的收集速度与效率,在原位形成固态水合物的前提下形成封存并转移,从而实现天然气水合物海域采集作业的低能耗、无污染开发、并改善海水缺氧与酸化程度、缓解温室气体排放效应。包括有冷泉扩孔及成品收集单元、冷泉集气种植单元和海底工程辅助单元。冷泉扩孔及成品收集单元,包括工程船或钻井平台、钻井装置和吊装系统；冷泉集气种植单元,包括固气采集装置和扩孔导流系统；海底工程辅助单元,包括通过爬行车脐带缆连接工程船或钻井平台的工程爬行车。(The invention relates to a sea area natural gas hydrate in-situ planting and collecting system and a method thereof, and provides a system and a method for reaming a hole in an in-situ well, intercepting and planting natural gas hydrate to implement subsequent collection. The method is used for accelerating the collection speed and efficiency of plume gas in a leakage area, and sealing and transferring are formed on the premise of in-situ formation of solid hydrate, so that low energy consumption and pollution-free development of natural gas hydrate sea area collection operation are realized, the anoxic and acidification degrees of seawater are improved, and the greenhouse gas emission effect is relieved. Comprises a cold spring reaming and finished product collecting unit, a cold spring gas-collecting planting unit and a submarine engineering auxiliary unit. The cold spring reaming and finished product collecting unit comprises an engineering ship or a drilling platform, a drilling device and a hoisting system; the cold spring gas collection planting unit comprises a solid gas collecting device and a reaming and flow guiding system; a submarine engineering auxiliary unit comprises an engineering crawler connected with an engineering ship or a drilling platform through a crawler umbilical cable.)

1. The in-situ planting and collecting system for the sea natural gas hydrate is characterized in that: comprises a cold spring reaming and finished product collecting unit, a cold spring gas-collecting planting unit and a submarine engineering auxiliary unit;

the cold spring reaming and finished product collecting unit comprises an engineering ship or a drilling platform (1), a drilling device (11) and a hoisting system (12);

the cold spring gas collection planting unit comprises a solid gas collection device (2) and a reaming and flow guiding system (4);

the solid gas acquisition device (2) comprises a pressure reduction gas transmission valve (21), a pressure sensor, an intelligent control unit (25) and an automatic sealing device (29);

the reaming and flow guiding system 4 comprises a casing (41), a perforation (42) arranged on the wall of the casing (41) and an wellhead flow control device (43);

the auxiliary unit for the submarine engineering comprises an engineering crawler (3) connected with an engineering ship or a drilling platform (1) through a crawler umbilical cable (31), and a crawler repeater (32) is connected to the crawler umbilical cable (31).

2. The in situ marine natural gas hydrate growing and harvesting system of claim 1, wherein: the solid gas collecting device (2) is characterized in that an anchoring weight block (27) connected with an anchor cable (28) is arranged at the bottom of the device, and a releaser (26) is connected to the anchor cable (28).

3. The in situ marine natural gas hydrate growing and harvesting system of claim 2, wherein: the solid gas acquisition device (2) is provided with a Beidou (or iridium) positioning device (22) and a hoisting ring (23).

4. An in-situ planting and collecting method of an in-situ sea area natural gas hydrate growing and collecting system according to claims 1 to 3, characterized by: comprises the operation implementation process of a cold spring reaming and finished product collecting unit and a cold spring gas-collecting planting unit;

the operation process of the cold spring reaming and finished product collecting unit is as follows,

firstly, drilling and reaming a cold spring leakage center by using an engineering ship or a drilling platform (1) and a drilling device (11);

then, a reaming diversion system (4) is arranged and supported, and a sleeve (41) with a perforation (42) is arranged, so that fluid enters the sleeve (41) along with the pressure difference between the inside and the outside;

the operation implementation process of the cold spring gas-collecting planting unit is as follows,

firstly, throwing an engineering crawler (3) from an engineering ship or a drilling platform (1);

then, an anchoring weight (27) is thrown in;

then, arranging a solid gas collecting device (2);

in the whole collection process, the buoyancy of the solid gas collection device (2) is sensed by a pressure sensor and an intelligent control unit (25), and when a preset threshold value is reached, the solid gas collection device (2) is separated from an anchoring weight block (27) and floats to the sea surface to rise under the driving of the buoyancy difference;

finally, when the solid gas collecting device (2) reaches the sea surface, the solid gas is collected by the hoisting system (12) through the hoisting ring (23); after the solid hydrate is completely decomposed, outputting methane gas by using a pressure reduction gas transmission valve (21);

and the solid gas collecting device (2) completes one construction process and is continuously used for repeating the next construction process.

5. The in-situ planting and collecting method of sea natural gas hydrates according to claim 4, wherein: in the operation process of the cold spring reaming and finished product collecting unit, a wellhead flow control device (43) is arranged at the seabed wellhead; during production, the engineering crawler (3) is used to close and open the wellhead flow control device (43).

6. The in-situ planting and collecting method of sea natural gas hydrates according to claim 4 or 5, wherein: in the operation process of the cold spring reaming and finished product collecting unit, the engineering crawler (3) is connected with an engineering ship or a drilling platform (1) through a crawler umbilical cable (31) and is provided with a crawler repeater (32).

7. The in-situ planting and collecting method of sea natural gas hydrates according to claim 6, wherein: and in the operation process of the cold spring reaming and finished product collecting unit, an engineering crawler (3) is used for throwing the anchoring weight block (27) and properly arranging the anchoring weight block around the reaming and flow guiding system (4).

8. The in-situ planting and collecting method of sea natural gas hydrates according to claim 7, wherein: in the operation process of the cold spring reaming and finished product collecting unit, the engineering crawler (3) is used for connecting the solid gas collecting device (2) with the anchoring weight block (27) through the anchor cable (28).

9. The in-situ planting and collecting method of sea natural gas hydrates according to claim 8, wherein: when the internal pressure of the solid-gas acquisition device (2) reaches a preset threshold value, the automatic sealing device (29) closes the solid-gas acquisition device (2) in an air tightness processing mode; the pressure sensor and the intelligent control unit (25) give an instruction to the releaser (26) to release the solid gas acquisition device (2).

Technical Field

The invention relates to an in-situ planting and collecting system and method for a sea area shallow surface layer natural gas hydrate (shown as a seabed cold spring or fluid leakage) under natural conditions, and belongs to the technical field of ocean resource development engineering.

Background

The natural gas hydrate is used as a novel, high-efficiency and environment-friendly energy source and is widely distributed in the world, and the conservative estimation of the total amount of the hydrate of the global resource level is about nx10¹⁵m³(hundreds of millions of cubic meters) are considered as the most promising alternative energy source for petroleum and natural gas in the future by various countries.

Natural gas hydrates are crystalline compounds produced naturally and composed of hydrocarbon gases mainly including methane and water molecules, usually in the form of ice and snow, chemically belonging to "clathrate inclusions", and usually generated and existing in a low-temperature (0-10 ℃) and high-pressure (greater than 10.1MPa) environment. The content of methane in the natural gas hydrate is 80-99.9%, the natural gas hydrate is an efficient and clean energy resource, the energy density of the natural gas hydrate is 10 times that of coal or carbonaceous shale and 2 times that of conventional natural gas, and the combustion pollution of the natural gas hydrate is much less than that of traditional fossil fuels such as coal, petroleum and natural gas.

Extensive research studies have demonstrated that 99% of the total natural gas hydrates are present in the ocean and that the natural gas hydrates are shallower in depth than conventional reservoirs, primarily in surface deposits on landscapes, islands and basins. The hydrate is a metastable compound, and can still form after being discharged into a water body due to leakage of a cold spring as long as the water depth is enough, so that the phenomenon that the hydrate forms in an investigation container after methane bubbles overflow is found in cold spring investigation of many places in the world, and hydrate shells are rapidly formed on the surface of the methane bubbles after the methane bubbles overflow. Because the density of the hydrate is less than that of water, the formed hydrate crystals quickly float to the upper water body until the upper part of the stable zone is decomposed and melted. Therefore, based on the natural law, how to utilize the natural gas hydrate leakage phenomenon (namely seabed cold spring activity) to finally obtain clean methane gas from the seabed can overcome the problems of higher economic cost and greater environmental pollution of the existing drilling development, and simultaneously realize interception of the leaked methane gas from the source, solve the problems of seawater acidification and oxygen deficiency and increased greenhouse effect gas emission in the atmosphere caused by the leakage of the natural gas hydrate, and is an important technical problem in the current exploitation and collection of the natural gas hydrate in the sea area.

As described in the following prior application patent, application No. cn201710228147.x, entitled deep sea hydrothermal metal sulfide deposit in situ planting system. The in-situ planting system provided by the application utilizes natural factors to cultivate the deep-sea hydrothermal metal sulfide deposit so as to reduce the exploitation cost and avoid polluting the environment. The hydrothermal solution metal sulfide hill body is penetrated into the drilling casing, the hydrothermal solution metal sulfide hill body sequentially comprises a water-resisting layer, a hydrothermal solution fluid enrichment layer and a hill body bedrock from outside to inside, the wall of the drilling casing at the hydrothermal solution fluid enrichment layer is provided with a perforation hole, the top end of the drilling casing is provided with the wellhead control diversion device, the bottom end of the fluid mixing control cover is provided with a lower opening, the lower opening is sleeved around the top end of the drilling casing, the top end of the fluid mixing control cover is provided with an upper opening, the side wall of the fluid mixing control cover is provided with a plurality of fluid holes, and the inner wall of the fluid mixing control cover is provided with a sulfide mineral coating.

Also as in the following prior application, application No. 201710228024.6, entitled deep sea hydrothermal metal sulfide harvesting electrolysis system. This application is with reducing the exploitation, smelt and cost of transportation as the purpose, including the collection ore robot, mining platform, metal sulphide electrolytic bath and thermoelectric generator, arrange a plurality of collection ore robot on the metal sulphide deposit, the collection ore robot is through ore transfer passage connection mining platform, mining platform is through mining backward flow water discharge tube coupling ocean, set up metal sulphide electrolytic bath on the mining platform, metal sulphide electrolytic bath is through electrolysis waste water discharge tube coupling ocean, thermoelectric generator's hot junction is placed in the hydrothermal spout department of metal sulphide deposit, thermoelectric generator's cold junction is placed in bottom sea water, thermoelectric generator is through cable junction metal sulphide electrolytic bath.

The 2 references mentioned above collectively embody the technology of in-situ planting and collecting metal sulfides in deep sea areas, in liquid or solid forms, and disclose that hydrothermal metal minerals are stable substances in the collection process of hydrothermal metal minerals, and do not involve the metastable state phenomena of gas-liquid mixing and solid-state transformation, which are peculiar to natural gas hydrates, so that no technical solutions are provided for forming solid hydrates, transferring and storing, and reducing methane gas escape, and such problems are exactly the problems that the collection process of sea natural gas hydrates must face and overcome.

In view of this, the present patent application is specifically proposed.

Disclosure of Invention

The invention relates to a sea area natural gas hydrate in-situ planting and collecting system and a method thereof, and provides a system and a method thereof for reaming a hole in an in-situ well, intercepting and planting natural gas hydrate to implement subsequent collection aiming at the current cold spring leakage all over the sea floor. The method aims to accelerate the improvement of the collection speed and efficiency of plume gas in a leakage area, and the sealing and transfer are formed on the premise of in-situ formation of solid hydrate, so that the purposes of low energy consumption and pollution-free development of natural gas hydrate sea area collection operation, improvement of seawater anoxia and acidification degree and alleviation of greenhouse gas emission effect are realized.

In order to achieve the design purpose, the in-situ planting and collecting system for the sea area natural gas hydrate mainly comprises a cold spring reaming and finished product collecting unit, a cold spring gas collection planting unit and a seabed engineering auxiliary unit. Wherein the content of the first and second substances,

the cold spring reaming and finished product collecting unit comprises an engineering ship or a drilling platform, a drilling device and a hoisting system;

the cold spring gas collection planting unit comprises a solid gas collecting device and a reaming and flow guiding system; the solid gas collecting device comprises a pressure reduction gas transmission valve, a pressure sensor, an intelligent control unit and an automatic sealing device; the reaming diversion system comprises a casing, and a perforation and a wellhead flow control device which are arranged on the wall of the casing;

the auxiliary unit for the submarine engineering comprises an engineering crawler connected with an engineering ship or a drilling platform through a crawler umbilical cable, and a crawler repeater is connected to the crawler umbilical cable.

According to the design concept, after the cold spring reaming unit and the finished product collecting unit reach a free gas layer through drilling, the free gas is enabled to be discharged to play a role in reducing pressure, further leakage of the block-shaped hydrate serving as a cover layer at the upper part is promoted, and the discharge flux of methane gas at the leakage point of the hydrate is increased;

the cold spring gas collection planting unit is responsible for properly guiding escaped gas into the collection planting unit, quickly forming solid hydrate crystals in situ by utilizing the characteristic of a hydrate stability zone existing in natural gas, and performing proper pressure maintaining and self-closing operation after the whole collection unit is filled with hydrate solids.

The submarine engineering auxiliary unit mainly uses a crawler to accurately distribute, collect and the like the collecting and planting units, and finally realizes pollution-free development of sea area natural gas hydrate.

Therefore, the in-situ planting and collecting system for the sea natural gas hydrate realizes acceleration and collection of plume gas of a hydrate leakage area, forms solid hydrate in situ, then carries out sealing, naturally gasifies in the process of upward self-floating after underwater release, and transfers and seals in a sea engineering ship or an engineering platform, thereby realizing low energy consumption and pollution-free development of the natural gas hydrate. By applying the device, the escape of methane gas can be effectively reduced, the anoxic and acidification degrees of seawater are improved, and the greenhouse gas effect in the atmosphere is favorably relieved; meanwhile, the traditional drilling development of natural gas hydrate resources is changed into intensive control planting, so that the interference of silt is removed, the high-quality natural gas hydrate is obtained, and meanwhile, the shape of the obtained ore body can be uniformly controlled, so that the ore body is more suitable for the flow industrial operation in the later gas production process of liquefying and separating methane, the production efficiency is improved, and because only water bodies are discharged from an engineering ship or a platform in the production process, the environmental pollution hardly exists.

Furthermore, the solid gas collecting device is provided with an anchoring weight block connected with an anchor rope, and the anchor rope is connected with a releaser. When the buoyancy of the hydrate in the device reaches the upper limit, under the indication of the pressure sensor and the intelligent control unit, the device is integrally and automatically unhooked from the seabed and self-floats to the sea surface by utilizing the characteristic that the total density is less than that of the sea water, so as to be beneficial to collection by an engineering platform or an engineering ship.

In addition, the solid gas acquisition device is provided with a Beidou (or iridium) positioning device and a hoisting ring so as to avoid losing or entering dangerous positions of an engineering ship or a drilling platform in the ascending process.

Based on the in-situ planting and collecting system applying the sea natural gas hydrate, the application simultaneously provides a new hydrate in-situ planting and collecting method, which comprises the operation implementation process of a cold spring reaming and finished product collecting unit and a cold spring gas collection planting unit. In particular, the amount of the solvent to be used,

the operation process of the cold spring reaming and finished product collecting unit is as follows:

firstly, drilling and reaming a cold spring leakage center by using an engineering ship or a drilling platform and a drilling device;

then, a reaming diversion system is arranged and supported, and a sleeve with a perforation is arranged, so that fluid enters the sleeve along with the pressure difference between the inside and the outside;

the operation implementation process of the cold spring gas-collecting planting unit is as follows,

firstly, throwing an engineering crawler from an engineering ship or a drilling platform;

then, an anchoring weight is put in;

then, arranging a solid gas collecting device;

in the whole collection process, the buoyancy of the solid-gas collection device is sensed by the pressure sensor and the intelligent control unit, and when the preset threshold value is reached, the solid-gas collection device is separated from the anchoring weight block and floats to the sea surface to rise under the driving of the buoyancy difference;

finally, when the solid gas collecting device reaches the sea level, the solid gas is collected by the hoisting system through the hoisting ring; after the solid hydrate is completely decomposed, outputting methane gas by using a pressure reduction gas transmission valve;

and finishing a solid gas collecting device of a construction process, and continuously repeating the next construction process.

Furthermore, in the operation process of the cold spring reaming and finished product collecting unit, in order to obtain better natural gas hydrate and improve the operation efficiency of collecting the hydrate, a wellhead flow control device can be arranged at the submarine wellhead; during production, the engineering crawler is used to close and open the wellhead flow control device.

In the operation process of the cold spring reaming and finished product collecting unit, the engineering crawler is connected with an engineering ship or a drilling platform through a crawler umbilical cable and is provided with a crawler repeater so as to improve the moving flexibility and the controlled performance of the engineering crawler.

On this basis, utilize engineering crawl car to put in anchoring pouring weight and arrange it properly around reaming water conservancy diversion system to and, utilize engineering crawl car to be connected solid for the gas collection system anchor rope and anchoring pouring weight.

When the internal pressure of the solid gas collecting device is monitored to reach a preset threshold value, the automatic sealing device closes the solid gas collecting device in an air tightness processing mode; the pressure sensor and the intelligent control unit give an instruction to the releaser to release the solid gas acquisition device.

In summary, the sea area natural gas hydrate in-situ planting and collecting system and the sea area natural gas hydrate in-situ planting and collecting method have the advantages and beneficial effects that plume gas of a hydrate leakage area is accelerated and collected, solid hydrate is formed in situ, then sealing is carried out, after underwater release, natural gasification is carried out in the upward self-floating process, and transfer sealing is carried out on a sea surface engineering ship or an engineering platform, so that low-energy consumption and pollution-free development of the natural gas hydrate are realized. By applying the device, the escape of methane gas can be effectively reduced, the anoxic and acidification degrees of seawater are improved, and the greenhouse gas effect in the atmosphere is favorably relieved; meanwhile, the traditional drilling development of natural gas hydrate resources is changed into intensive control planting, so that the interference of silt is removed, the high-quality natural gas hydrate is obtained, and meanwhile, the shape of the obtained ore body can be uniformly controlled, so that the ore body is more suitable for the flow industrial operation in the later gas production process of liquefying and separating methane, the production efficiency is improved, and because only water bodies are discharged from an engineering ship or a platform in the production process, the environmental pollution hardly exists.

Drawings

The drawings are included to further detail the design concepts and features of the application.

Fig. 1 is a schematic diagram of an in-situ planting and collecting system for sea natural gas hydrates.

In the figure, 1, an engineering ship or a drilling platform, 11, a drilling device, 12 and a hoisting system; 2. the device comprises a solid gas acquisition device, a pressure reduction gas transmission valve 21, a Beidou (or iridium) positioning device, a lifting ring 23, a lifting ring 24, a formed solid hydrate 25, a pressure sensor and intelligent control unit 26, a releaser 27, an anchoring weight 28, an anchor cable 29 and an automatic sealing device; 3. engineering creeper truck, 31-creeper truck umbilical cable, 32, creeper truck repeater; 4. a reaming diversion system 41, a casing 42, a perforation 43 and an wellhead flow control device; 5. mud volcanoes developing cold springs and shallow hydrate layers, 51, overburden layer, 52, solid hydrate layer, 53, free gas layer under hydrate layer, 54, lower sediment layer or bedrock, 55, primary fracture zone (fluid rapid leakage zone).

Detailed Description

The present application is further described with reference to the accompanying drawings and the following preferred embodiments.