技术领域Technical Field
本发明涉及一种天然气水合物的开采技术，具体是涉及一种天然气水合物原位加热排采装置及其排采方法。The invention relates to a natural gas hydrate mining technology, in particular to a natural gas hydrate in-situ heating and mining device and a mining method thereof.
背景技术Background technique
天然气水合物是由水分子和充填其中的客体分子形成的包络型化合物，在低温、高压环境下以晶体形式存在。自然界中的天然气水合物主要以甲烷水合物为主，赋存于低温高压环境条件的永久冻土区和深海沉积物中，1单位体积的甲烷水合物分解可产生150-180标准体积的甲烷气体和0.8标准体积的水，具有储量巨大、分布广泛、埋藏深度浅、能量密度高的优点，据估计，地球上以天然气水合物形式储藏的有机碳占全球总有机碳的53％，是煤、石油、天然气三种化石燃料总碳量的2倍。因此，天然气水合物被认为是21世纪的理想清洁替代能源，具有良好的应用前景。Natural gas hydrates are envelope compounds formed by water molecules and guest molecules filled therein, and exist in the form of crystals under low temperature and high pressure environments. Natural gas hydrates in nature are mainly methane hydrates, which exist in permafrost areas and deep-sea sediments under low temperature and high pressure environmental conditions. The decomposition of 1 unit volume of methane hydrate can produce 150-180 standard volumes of methane gas and 0.8 standard volumes of water. It has the advantages of huge reserves, wide distribution, shallow burial depth, and high energy density. It is estimated that the organic carbon stored in the form of natural gas hydrates on the earth accounts for 53% of the total organic carbon in the world, which is twice the total carbon content of the three fossil fuels of coal, oil, and natural gas. Therefore, natural gas hydrates are considered to be an ideal clean alternative energy source in the 21st century and have good application prospects.
由于天然气水合物存在固液气三种相态的变化，与常规的石油天然气相比存在较大的开采难度，从2002年开始，在加拿大北极地区马利克(Mallik)站位开展的天然气水合物试采及研究，证实了通过加热、降压均可实现将天然气水合物分解成气态及液态进行流动，从而拉开了天然气水合物高效开采的研究序幕。目前国际上普遍认可的天然气水合物开采方法主要有：降压法、热激法、二氧化碳置换法以及这些方法的组合应用，其开采手段主要是参考常规的油气开采工艺，首先通过钻井建立井筒直达天然气水合物的储层，然后采用合适的物理化学手段，改变储层的温度或者压力等热力学条件，破坏水合物的结合环境，促进天然气水合物分解为水和天然气，最后将分解后的天然气和水收集、输送至地面，从而实现天然气水合物的开采。Since natural gas hydrates have three phase changes of solid, liquid and gas, they are more difficult to exploit than conventional oil and natural gas. Since 2002, the trial production and research of natural gas hydrates carried out at Mallik Station in the Canadian Arctic have confirmed that natural gas hydrates can be decomposed into gas and liquid states for flow by heating and depressurization, thus opening the prelude to the research on efficient exploitation of natural gas hydrates. At present, the main methods of natural gas hydrate exploitation generally recognized internationally are: depressurization method, thermal shock method, carbon dioxide replacement method and the combined application of these methods. The exploitation means mainly refer to the conventional oil and gas exploitation process. First, a wellbore is established by drilling to directly reach the reservoir of natural gas hydrates, and then appropriate physical and chemical means are used to change the thermodynamic conditions such as temperature or pressure of the reservoir, destroy the binding environment of hydrates, promote the decomposition of natural gas hydrates into water and natural gas, and finally collect and transport the decomposed natural gas and water to the ground, so as to realize the exploitation of natural gas hydrates.
近30年以来，各国科学家对天然气水合物的开发技术已经进行了比较系统的实验室实验和小规模的现场开采实验，验证了各种天然气水合物的开采技术和方法，主要开采机理还是通过降低天然气水合物储层的压力至热力学平衡线之下，使得天然气水合物分解，但天然气水合物分解过程需要吸收大量的热，导致储层的温度随之降低，当温度降到一定程度时，又反过来影响天然气水合物的相平衡，使得储层孔隙内自由水结冰和水合物二次生成，堵塞孔隙通道，降低储层的渗透率，因此，维持并提高储层的温度，对天然气水合物的开采有着非常重要的意义。Over the past 30 years, scientists from various countries have conducted relatively systematic laboratory experiments and small-scale field mining experiments on the development technology of natural gas hydrates, and verified various natural gas hydrate mining technologies and methods. The main mining mechanism is to reduce the pressure of the natural gas hydrate reservoir to below the thermodynamic equilibrium line to decompose the natural gas hydrate. However, the decomposition process of natural gas hydrates requires the absorption of a large amount of heat, causing the temperature of the reservoir to decrease. When the temperature drops to a certain level, it in turn affects the phase equilibrium of the natural gas hydrate, causing the free water in the reservoir pores to freeze and hydrates to form secondary, blocking the pore channels and reducing the permeability of the reservoir. Therefore, maintaining and increasing the temperature of the reservoir is of great significance to the mining of natural gas hydrates.
国家知识产权局公开了公开号为CN1920251B的专利文献，它具体公开了以下内容：本发明采取了以下的技术方案：1)构筑开采井及集气井。首先采用深水钻井技术领域的现有技术在水合物成矿区构筑开采井及集气井，并构筑开采井与集气井之间的连接通道；开采井及集气井贯穿至水合物储层底部。2)天然气水合物分解。向水合物储层注入水合物分解促进剂，将天然气水合物分解为天然气和水，同时在安装于开采井下的催化氧化燃烧器中采用氧化剂原位催化氧化燃烧燃料加热载热流体，然后将载热流体泵入水合物储层供给天然气水合物分解所需的热能，将催化氧化燃烧所产生的CO2气体注入水合物储层，使其形成CO2水合物填充甲烷水合物开采后留下的空隙，CO2水合物生成所释放的热量传递给水合物分解促进剂，用于天然气水合物的分解，CO2水合物形成吸收分解促进剂中的水份，提高了水合物分解促进剂的浓度。3)分解后的天然气导出。通过天然气导出管道将分解后的天然气收集至海面上的分离、储气装置。The State Intellectual Property Office has published a patent document with a publication number of CN1920251B, which specifically discloses the following: The present invention adopts the following technical solutions: 1) Constructing mining wells and gas collection wells. First, the existing technology in the field of deep-water drilling technology is used to construct mining wells and gas collection wells in the hydrate mineralization area, and a connecting channel between the mining wells and the gas collection wells is constructed; the mining wells and the gas collection wells penetrate to the bottom of the hydrate reservoir. 2) Decomposition of natural gas hydrates. A hydrate decomposition promoter is injected into the hydrate reservoir to decompose the natural gas hydrate into natural gas and water. At the same time, an oxidant is used in situ in the catalytic oxidation burner installed under the mining well to catalytically oxidize and burn fuel to heat the heat-carrying fluid, and then the heat-carrying fluid is pumped into the hydrate reservoir to supply the heat energy required for the decomposition of natural gas hydrates. The CO2 gas generated by the catalytic oxidation combustion is injected into the hydrate reservoir to form CO2 hydrates to fill the gaps left after the methane hydrate is mined. The heat released by the formation of CO2 hydrates is transferred to the hydrate decomposition promoter for the decomposition of natural gas hydrates. The CO2 hydrate formation absorbs the water in the decomposition promoter, thereby increasing the concentration of the hydrate decomposition promoter. 3) Decomposed natural gas is exported. The decomposed natural gas is collected through a natural gas export pipeline and sent to a separation and gas storage device on the sea surface.
所述步骤(2)天然气水合物分解可以具体细化为以下步骤：(1)催化氧化燃烧器采用电加热点火预热；(2)向安装于开采井中的催化氧化燃烧器输送燃料及氧化剂，燃料及氧化剂在预热器中预热；(3)在催化剂作用下，燃料在井下催化氧化燃烧器中被氧化剂催化氧化，放出热量加热载热流体；(4)向天然气水合物储层注入水合物分解促进剂，将天然气水合物分解为天然气和水；(5)载热流体输送至水合物储层加热水合物分解促进剂及天然气水合物储层，促进天然气水合物的分解；(6)将催化氧化燃烧产物输送至水合物储层，控制水合物储层温度低于CO2水合物稳定温度，高于CH4水合物稳定温度；(7)催化氧化燃烧产物中的CO2在水合物储层形成CO2水合物，放出水合物生成热加热水合物分解促进剂；(8)CO2水合物形成吸收水合物分解促进剂中的水份，水合物分解促进剂浓度升高，对天然气水合物的分解速率加快。The step (2) of decomposing natural gas hydrates can be specifically divided into the following steps: (1) preheating the catalytic oxidation burner by electric heating; (2) delivering fuel and oxidant to the catalytic oxidation burner installed in the production well, and preheating the fuel and oxidant in the preheater; (3) under the action of the catalyst, the fuel is catalytically oxidized by the oxidant in the downhole catalytic oxidation burner, and heat is released to heat the heat-carrying fluid; (4) injecting a hydrate decomposition promoter into the natural gas hydrate reservoir to decompose the natural gas hydrate into natural gas and water; (5) delivering the heat-carrying fluid to the hydrate reservoir for heating Hydrate decomposition promoter and natural gas hydrate reservoir, promoting the decomposition of natural gas hydrate; (6) transporting the catalytic oxidation combustion products to the hydrate reservoir, controlling the hydrate reservoir temperature to be lower than the CO2 hydrate stability temperature and higher than the CH4 hydrate stability temperature; (7) the CO2 in the catalytic oxidation combustion products forms CO2 hydrate in the hydrate reservoir, releasing the hydrate formation heat to heat the hydrate decomposition promoter; (8) the CO2 hydrate formation absorbs the water in the hydrate decomposition promoter, the concentration of the hydrate decomposition promoter increases, and the decomposition rate of natural gas hydrate is accelerated.
上述技术方案将燃烧器生成的载热流体导入到天然气水合物储层中，对天然气水合物储层进行加热，由于天然气水合物储层的压力较大，将载热流体导入到天然气水合物储层中，在实际操作中有一定的难度，采用该技术进行加热的方式实际使用效果很不理想。并且上述技术方案需要创建两个井，一个集气井和一个开采井，集气成本高。The above technical solution introduces the heat-carrying fluid generated by the burner into the natural gas hydrate reservoir to heat the natural gas hydrate reservoir. Due to the high pressure of the natural gas hydrate reservoir, it is difficult to introduce the heat-carrying fluid into the natural gas hydrate reservoir in actual operation. The actual use effect of the heating method using this technology is not ideal. In addition, the above technical solution requires the creation of two wells, a gas collection well and a production well, and the gas collection cost is high.
发明内容Summary of the invention
本发明的目的在于提供一种天然气水合物原位加热排采装置，该排采装置具有实用性强、开采效率高、操作方便的特点。The object of the present invention is to provide a natural gas hydrate in-situ heating and drainage device, which has the characteristics of strong practicability, high mining efficiency and convenient operation.
本发明的目的在于提供一种天然气水合物原位加热排采的方法，具有开采效率高，成本低廉的特点。The object of the present invention is to provide a method for in-situ heating and drainage of natural gas hydrate, which has the characteristics of high mining efficiency and low cost.
为解决上述技术问题，本发明所采用的技术方案是：In order to solve the above technical problems, the technical solution adopted by the present invention is:
一种天然气水合物原位加热排采装置，包括同轴连续油管、电子点火环和燃烧助剂喷管，所述同轴连续油管包括外管、内管和外管接头，电子点火环设在燃烧助剂喷管上，燃烧助剂喷管与内管的一端连通，内管的另一端从外管中穿过与燃烧助剂高压气源连通，所述外管接头安装在外管的端部，用以将内管和外管固定在一起，并使内管和外管同轴心安装，所述外管与内管之间的环空为天然气采排通道，所述外管接头上设有与天然气采排通道相通的天然气采排孔。A natural gas hydrate in-situ heating and drainage device comprises a coaxial continuous oil pipe, an electronic ignition ring and a combustion aid nozzle, wherein the coaxial continuous oil pipe comprises an outer pipe, an inner pipe and an outer pipe joint, the electronic ignition ring is arranged on the combustion aid nozzle, the combustion aid nozzle is connected with one end of the inner pipe, and the other end of the inner pipe passes through the outer pipe and is connected with a combustion aid high-pressure gas source, the outer pipe joint is installed at the end of the outer pipe, and is used to fix the inner pipe and the outer pipe together, and to install the inner pipe and the outer pipe coaxially, the annulus between the outer pipe and the inner pipe is a natural gas drainage channel, and the outer pipe joint is provided with a natural gas drainage hole connected with the natural gas drainage channel.
进一步地，所述燃烧助剂为氧气，燃烧助剂高压气源包括制氧设备和气体增压设备，制氧设备的氧气经气体增压设备增压后送入内管。Furthermore, the combustion aid is oxygen, and the high-pressure gas source of the combustion aid includes an oxygen production device and a gas boosting device. The oxygen from the oxygen production device is pressurized by the gas boosting device and then fed into the inner tube.
进一步地，所述燃烧助剂喷管的一端设有卡瓦连接器，卡瓦连接器通过锁定锚钉与内管连接，所述燃烧助剂喷管的另一端为封闭的圆锥状结构，圆锥状结构的圆锥面上分布有多个燃烧助剂出口；所述外管通过锁定锚钉与外管接头连接。Furthermore, a slip connector is provided at one end of the combustion aid nozzle, which is connected to the inner tube through a locking anchor. The other end of the combustion aid nozzle is a closed conical structure, and a plurality of combustion aid outlets are distributed on the conical surface of the conical structure; the outer tube is connected to the outer tube joint through a locking anchor.
进一步地，所述燃烧助剂喷管上设有氧气浓度传感器和温度压力传感器。Furthermore, the combustion aid nozzle is provided with an oxygen concentration sensor and a temperature and pressure sensor.
进一步地，所述燃烧助剂喷管上设有二氧化碳浓度传感器。Furthermore, a carbon dioxide concentration sensor is provided on the combustion aid nozzle.
进一步地，所述燃烧助剂喷管上设有两个陶瓷绝缘滑环，所述氧气浓度传感器、温度压力传感器和二氧化碳浓度传感器位于两个陶瓷绝缘滑环之间。Furthermore, two ceramic insulating slip rings are provided on the combustion aid nozzle, and the oxygen concentration sensor, the temperature and pressure sensor and the carbon dioxide concentration sensor are located between the two ceramic insulating slip rings.
进一步地，所述内管中设有电缆线，所述电缆线同时与温度压力传感器、二氧化碳浓度传感器、氧气浓度传感器和电子点火环电连接。Furthermore, an electric cable is provided in the inner tube, and the electric cable is electrically connected to the temperature and pressure sensor, the carbon dioxide concentration sensor, the oxygen concentration sensor and the electronic ignition ring at the same time.
进一步地，所述氧气浓度传感器设有两个，两个氧气浓度传感器位于电子点火环的旁边，所述二氧化碳浓度传感器位于两个氧气浓度传感器之间。Furthermore, two oxygen concentration sensors are provided, the two oxygen concentration sensors are located beside the electronic ignition ring, and the carbon dioxide concentration sensor is located between the two oxygen concentration sensors.
一种天然气水合物原位加热排采的方法，通过同轴连续油管将助燃剂输送到位于地下天然气水合物储层中的开采井水平段内，助燃剂与开采井水平段内的天然气混合成为可燃气体，利用电子点火装置点燃可燃气体，并拉动同轴连续油管，以带动燃烧助剂喷管在开采井水平段中往复移动，对开采井水平段的井壁进行加热，开采井水平段的井壁将热量传递给天然气水合物储层，促使天然气水合物储层中的天然气水合物快速分解成天然气和水，天然气和水通过同轴连续油管的内外管间的环空通道排出到海洋平台甲板上的处理系统。A method for in-situ heating and drainage of natural gas hydrates comprises the following steps: a combustion aid is transported to a horizontal section of a production well located in an underground natural gas hydrate reservoir through a coaxial continuous oil pipe; the combustion aid is mixed with the natural gas in the horizontal section of the production well to form a combustible gas; an electronic ignition device is used to ignite the combustible gas, and the coaxial continuous oil pipe is pulled to drive a combustion aid nozzle to move back and forth in the horizontal section of the production well, thereby heating the well wall of the horizontal section of the production well; the well wall of the horizontal section of the production well transfers heat to the natural gas hydrate reservoir, thereby causing the natural gas hydrate in the natural gas hydrate reservoir to quickly decompose into natural gas and water; the natural gas and water are discharged to a processing system on an offshore platform deck through an annular channel between inner and outer pipes of the coaxial continuous oil pipe.
进一步地，天然气水合物原位加热排采的具体步骤如下：Furthermore, the specific steps of in-situ heating and drainage of natural gas hydrate are as follows:
S1、构建开采井：利用现代钻井技术，在天然气水合物储层内建立带有水平段的初始井，然后在初始井内下入套管及防砂管柱，最后安装井口，完成开采井的建井工程；S1. Construction of mining wells: Using modern drilling technology, an initial well with a horizontal section is built in the natural gas hydrate reservoir, and then casing and sand control pipes are run into the initial well, and finally the wellhead is installed to complete the construction of the mining well;
S2、安装原位加热排采装置：在海洋平台上安置同轴连续油管作业设备、制氧设备、气体增压设备，设备之间通过高压管线连接；S2. Install in-situ heating and drainage equipment: Install coaxial coiled tubing equipment, oxygen production equipment, and gas boosting equipment on the offshore platform, and connect the equipment through high-pressure pipelines;
S3、输送燃烧助剂喷管到开采井：同轴连续油管与燃烧助剂喷管安装连接后，利用同轴连续油管作业设备将同轴连续油管连续向开采井内输送，将输送燃烧助剂喷管输送到开采井的水平段中；S3. Transporting the combustion aid nozzle to the production well: After the coaxial coiled tubing is installed and connected with the combustion aid nozzle, the coaxial coiled tubing operation equipment is used to continuously transport the coaxial coiled tubing into the production well, and the combustion aid nozzle is transported to the horizontal section of the production well;
S4、输送氧气到开采井：启动制氧设备，制氧设备提供的氧气，通过气体增压设备增压后，经同轴连续油管的内管输送到输送燃烧助剂喷管，氧气经燃烧助剂喷管进入开采井的水平段中；S4. Transporting oxygen to the production well: Start the oxygen generator. The oxygen provided by the oxygen generator is pressurized by the gas booster and then transported to the combustion aid nozzle through the inner tube of the coaxial coiled tubing. The oxygen enters the horizontal section of the production well through the combustion aid nozzle;
S5、抽取开采井中的液体：将开采井内的液体经同轴连续油管的内外管之间的环空排出到海洋平台上的液体处理系统；S5. Extracting liquid from the production well: discharging the liquid in the production well through the annulus between the inner and outer pipes of the coaxial coiled tubing to the liquid treatment system on the offshore platform;
S6、点燃可燃气体：待开采井内的液体被完全排空后，启动电子点火环，点燃开采井内水平段的可燃气体；S6, ignite the combustible gas: after the liquid in the mining well is completely emptied, start the electronic ignition ring to ignite the combustible gas in the horizontal section of the mining well;
S7、氧气流量的调节：通过燃烧助剂喷管上面的温度压力传感器和氧气浓度传感器的回馈参数，调节注入氧气的流量，以控制燃烧强度；S7. Regulation of oxygen flow: by using the feedback parameters of the temperature and pressure sensor and oxygen concentration sensor on the combustion aid nozzle, the flow of injected oxygen is regulated to control the combustion intensity;
S8、控制燃烧区域：控制同轴连续油管的起出及下入的速度，以拖动燃烧助剂喷管在开采井内水平段的往复移动，以不断改变开采井内水平段的加热位置，从而实现对燃烧面的控制；S8. Control the combustion area: Control the speed of pulling out and lowering the coaxial coiled tubing to drag the combustion aid nozzle to move back and forth in the horizontal section of the mining well to continuously change the heating position of the horizontal section of the mining well, thereby achieving control of the combustion surface;
S9、排采天然气：关闭制氧设备，经加热后，天然气水合物储层中的天然气水合物分解为天然气和水，天然气和水进入到开采井内，天然气、水以及燃烧后的尾气，都通过同轴连续油管的内外管间的环空通道排出到海洋平台甲板上的处理系统。S9. Natural gas extraction: Shut down the oxygen production equipment, and after heating, the natural gas hydrate in the natural gas hydrate reservoir will decompose into natural gas and water. The natural gas and water will enter the extraction well, and the natural gas, water and exhaust gas after combustion will be discharged to the processing system on the deck of the offshore platform through the annular channel between the inner and outer pipes of the coaxial continuous oil pipe.
本发明的有益效果在于：The beneficial effects of the present invention are:
对开采井水平段的井壁进行加热，开采井水平段的井壁将热量传递给天然气水合物储层，产生的热量破坏水合物形成的热力学条件，促进水合物快速分解，使天然气水合物储层中的天然气水合物快速分解成天然气和水，同时，燃烧后的废气降低了井筒的液柱压力，为井筒内液体举升提供了充足的动力，本发明的装置及方法，本发明方法具有开采工艺简单、开采效率高、成本低廉、操作简单的特点，适用于海洋天然气水合物大规模工业化开采。The well wall of the horizontal section of the production well is heated, and the well wall of the horizontal section of the production well transfers heat to the natural gas hydrate reservoir. The generated heat destroys the thermodynamic conditions for the formation of hydrates, promotes the rapid decomposition of hydrates, and makes the natural gas hydrates in the natural gas hydrate reservoir quickly decompose into natural gas and water. At the same time, the exhaust gas after combustion reduces the liquid column pressure in the wellbore, providing sufficient power for lifting the liquid in the wellbore. The device and method of the present invention have the characteristics of simple production process, high production efficiency, low cost and simple operation, and are suitable for large-scale industrial production of marine natural gas hydrates.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
利用附图对本发明作进一步说明，但附图中的实施例不构成对本发明的任何限制，对于本领域的普通技术人员，在不付出创造性劳动的前提下，还可以根据以下附图获得其它的附图：The present invention is further described with the aid of the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other accompanying drawings according to the following drawings without creative work:
图1为本发明的结构示意图；Fig. 1 is a schematic diagram of the structure of the present invention;
图2为图1所示的分解图；FIG2 is an exploded view of FIG1 ;
图3为本发明实施过程中处于加热状态的示意图；FIG3 is a schematic diagram of a heating state during the implementation of the present invention;
图4为本发明的流程图。FIG. 4 is a flow chart of the present invention.
图中：1、外管；2、内管；3、外管接头；4、电子点火环；5、燃烧助剂喷管；6、天然气采排通道；7、天然气采排孔；8、卡瓦连接器；9、燃烧助剂出口；10、氧气浓度传感器；11、二氧化碳浓度传感器；12、温度压力传感器；13、电缆线；14、开采井；15、海洋平台；16、同轴连续油管；17、陶瓷绝缘滑环；18、水平段。In the figure: 1. outer pipe; 2. inner pipe; 3. outer pipe joint; 4. electronic ignition ring; 5. combustion aid nozzle; 6. natural gas production and drainage channel; 7. natural gas production and drainage hole; 8. slip connector; 9. combustion aid outlet; 10. oxygen concentration sensor; 11. carbon dioxide concentration sensor; 12. temperature and pressure sensor; 13. cable; 14. production well; 15. offshore platform; 16. coaxial continuous oil pipe; 17. ceramic insulating slip ring; 18. horizontal section.
具体实施方式Detailed ways
为了使本领域的技术人员更好地理解本发明的技术方案，下面结合附图和具体实施例对本发明作进一步详细的描述，需要说明的是，在不冲突的情况下，本申请的实施例及实施例中的特征可以相互组合。In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other without conflict.
如图1、图2所示，一种天然气水合物原位加热排采装置，包括同轴连续油管、电子点火环4和燃烧助剂喷管5，所述同轴连续油管16包括外管1、内管2和外管接头3，电子点火环4设在燃烧助剂喷管5上，燃烧助剂喷管5与内管2的一端连通，内管2的另一端从外管1中穿过与燃烧助剂高压气源连通，所述外管接头3安装在外管1的端部，用以将内管2和外管1固定在一起，并使内管2和外管1同轴心安装，外管1与内管2之间的环空为天然气采排通道6，外管接头3上设有与天然气采排通道6相通的天然气采排孔7。As shown in Figures 1 and 2, a natural gas hydrate in-situ heating and drainage device includes a coaxial coiled tubing, an electronic ignition ring 4 and a combustion aid nozzle 5. The coaxial coiled tubing 16 includes an outer tube 1, an inner tube 2 and an outer tube joint 3. The electronic ignition ring 4 is arranged on the combustion aid nozzle 5. The combustion aid nozzle 5 is connected to one end of the inner tube 2. The other end of the inner tube 2 passes through the outer tube 1 and is connected to a combustion aid high-pressure gas source. The outer tube joint 3 is installed at the end of the outer tube 1 to fix the inner tube 2 and the outer tube 1 together and install the inner tube 2 and the outer tube 1 coaxially. The annulus between the outer tube 1 and the inner tube 2 is a natural gas drainage channel 6. The outer tube joint 3 is provided with a natural gas drainage hole 7 that is connected to the natural gas drainage channel 6.
所述燃烧助剂为氧气，燃烧助剂高压气源包括制氧设备和气体增压设备，制氧设备的氧气经气体增压设备增压后送入内管。The combustion aid is oxygen, and the high-pressure gas source of the combustion aid includes oxygen production equipment and gas boosting equipment. The oxygen of the oxygen production equipment is pressurized by the gas boosting equipment and then sent into the inner tube.
燃烧助剂喷管5的一端设有卡瓦连接器8，卡瓦连接器8通过锁定锚钉与内管2连接，所述燃烧助剂喷管5的另一端为封闭的圆锥状结构，圆锥状结构的圆锥面上分布有多个燃烧助剂出口9；外管1通过锁定锚钉与外管接头3连接。A slip connector 8 is provided at one end of the combustion aid nozzle 5, and the slip connector 8 is connected to the inner tube 2 through a locking anchor. The other end of the combustion aid nozzle 5 is a closed conical structure, and a plurality of combustion aid outlets 9 are distributed on the conical surface of the conical structure; the outer tube 1 is connected to the outer tube joint 3 through a locking anchor.
燃烧助剂喷管5上设有氧气浓度传感器10。燃烧助剂喷管5上设有二氧化碳浓度传感器11。燃烧助剂喷管5上设有温度压力传感器12。所述氧气浓度传感器10设有两个，两个氧气浓度传感器10位于电子点火环4的旁边，所述二氧化碳浓度传感器11位于两个氧气浓度传感器10之间。An oxygen concentration sensor 10 is provided on the combustion aid nozzle 5. A carbon dioxide concentration sensor 11 is provided on the combustion aid nozzle 5. A temperature and pressure sensor 12 is provided on the combustion aid nozzle 5. Two oxygen concentration sensors 10 are provided, and the two oxygen concentration sensors 10 are located beside the electronic ignition ring 4, and the carbon dioxide concentration sensor 11 is located between the two oxygen concentration sensors 10.
燃烧助剂喷管5上设有两个陶瓷绝缘滑环17，所述氧气浓度传感器10、温度压力传感器12和二氧化碳浓度传感器11位于两个陶瓷绝缘滑环17之间。Two ceramic insulating slip rings 17 are provided on the combustion aid nozzle 5 , and the oxygen concentration sensor 10 , the temperature and pressure sensor 12 and the carbon dioxide concentration sensor 11 are located between the two ceramic insulating slip rings 17 .
内管2中设有电缆线13，所述电缆线13同时与温度压力传感器12、二氧化碳浓度传感器11、氧气浓度传感器10和电子点火环4电连接。An electric cable 13 is provided in the inner tube 2 , and the electric cable 13 is electrically connected to the temperature and pressure sensor 12 , the carbon dioxide concentration sensor 11 , the oxygen concentration sensor 10 and the electronic ignition ring 4 at the same time.
如图3所示，一种天然气水合物原位加热排采的方法，通过同轴连续油管将助燃剂输送到位于地下天然气水合物储层中的开采井14的水平段18内，助燃剂与开采井水平段内的天然气混合成为可燃气体，利用电子点火环4（电子点火装置）点燃可燃气体，并拉动同轴连续油管16，以带动燃烧助剂喷管5在开采井水平段18中往复移动，对开采井水平段18的井壁进行加热，开采井水平段的井壁将热量传递给天然气水合物储层，促使天然气水合物储层中的天然气水合物快速分解成天然气和水，天然气和水通过同轴连续油管的内外管间的环空通道排出到海洋平台甲板上的处理系统。As shown in FIG3 , a method for in-situ heating and drainage of natural gas hydrate is provided, wherein a combustion aid is transported to a horizontal section 18 of a production well 14 located in an underground natural gas hydrate reservoir through a coaxial continuous tubing, the combustion aid is mixed with the natural gas in the horizontal section of the production well to form a combustible gas, the combustible gas is ignited by an electronic ignition ring 4 (electronic ignition device), and the coaxial continuous tubing 16 is pulled to drive the combustion aid nozzle 5 to move back and forth in the horizontal section 18 of the production well, heating the well wall of the horizontal section 18 of the production well, and the well wall of the horizontal section of the production well transfers heat to the natural gas hydrate reservoir, prompting the natural gas hydrate in the natural gas hydrate reservoir to quickly decompose into natural gas and water, and the natural gas and water are discharged to the processing system on the deck of the offshore platform through the annular channel between the inner and outer pipes of the coaxial continuous tubing.
如图3、图4所示，具体来说，天然气水合物原位加热排采的具体步骤如下：As shown in Figures 3 and 4, the specific steps of in-situ heating and drainage of natural gas hydrate are as follows:
S1、构建开采井14：利用现代钻井技术，在天然气水合物储层内建立带有水平段18的初始井，然后在初始井内下入套管及防砂管柱，最后安装井口，完成开采井14的建井工程；S1. Construction of the production well 14: using modern drilling technology, an initial well with a horizontal section 18 is established in the natural gas hydrate reservoir, then casing and sand control pipe string are run into the initial well, and finally a wellhead is installed to complete the construction of the production well 14;
S2、安装原位加热排采装置：在海洋平台15上安置同轴连续油管作业设备、制氧设备和气体增压设备，各设备之间通过高压管线连接；S2. Installing in-situ heating and drainage equipment: Installing coaxial coiled tubing operation equipment, oxygen production equipment and gas pressurization equipment on the offshore platform 15, and connecting the equipment through high-pressure pipelines;
S3、输送燃烧助剂喷管到开采井：同轴连续油管16与燃烧助剂喷管5安装连接后，本发明所述的同轴连续油管是通过弯曲的方式缠绕在同轴连续油管作业设备的滚筒上，利用同轴连续油管作业设备将同轴连续油管连续向开采井14内输送，将输送燃烧助剂喷管输送到开采井14的水平段中；S3, conveying the combustion aid nozzle to the production well: After the coaxial coiled tubing 16 is installed and connected with the combustion aid nozzle 5, the coaxial coiled tubing of the present invention is wound on the drum of the coaxial coiled tubing operation equipment in a bending manner, and the coaxial coiled tubing operation equipment is used to continuously convey the coaxial coiled tubing into the production well 14, and the combustion aid nozzle is conveyed to the horizontal section of the production well 14;
S4、输送氧气到开采井14：启动制氧设备，制氧设备提供的氧气，通过气体增压设备增压后经同轴连续油管的内管输送到输送燃烧助剂喷管，氧气经燃烧助剂喷管进入开采井的水平段中；S4, transporting oxygen to the production well 14: starting the oxygen production equipment, the oxygen provided by the oxygen production equipment is pressurized by the gas booster and then transported to the combustion aid delivery nozzle through the inner tube of the coaxial coiled tubing, and the oxygen enters the horizontal section of the production well through the combustion aid nozzle;
S5、抽取开采井中的液体：将开采井内的液体经同轴连续油管的内外管之间的环空排出到海洋平台上的液体处理系统；S5. Extracting liquid from the production well: discharging the liquid in the production well through the annulus between the inner and outer pipes of the coaxial coiled tubing to the liquid treatment system on the offshore platform;
S6、点燃可燃气体：待开采井内的液体被完全排空后，启动电子点火环4，点燃开采井内水平段18的可燃气体；S6, igniting the combustible gas: after the liquid in the mining well is completely emptied, start the electronic ignition ring 4 to ignite the combustible gas in the horizontal section 18 of the mining well;
S7、氧气流量的调节：通过燃烧助剂喷管上面的温度压力传感器12和氧气浓度传感器10的回馈参数，调节注入氧气的流量，以控制燃烧强度；S7, oxygen flow rate adjustment: through the feedback parameters of the temperature and pressure sensor 12 and the oxygen concentration sensor 10 on the combustion aid nozzle, the flow rate of injected oxygen is adjusted to control the combustion intensity;
S8、控制燃烧区域：控制同轴连续油管16的起出及下入的速度，以拖动燃烧助剂喷管5在开采井内水平段18的往复移动，以不断改变开采井内水平段的加热位置，从而实现对燃烧面的控制；S8, control the combustion area: control the speed of pulling out and lowering the coaxial coiled tubing 16 to drag the combustion aid nozzle 5 to move back and forth in the horizontal section 18 in the mining well, so as to continuously change the heating position of the horizontal section in the mining well, thereby realizing the control of the combustion surface;
S9、排采天然气：关闭制氧设备，经加热后，天然气水合物储层中的天然气水合物分解为天然气和水，天然气、水以及燃烧后的尾气，都通过同轴连续油管16的内外管间的环空通道排出到海洋平台甲板上的处理系统。S9. Natural gas extraction: shut down the oxygen production equipment, and after heating, the natural gas hydrate in the natural gas hydrate reservoir is decomposed into natural gas and water. The natural gas, water and exhaust gas after combustion are discharged to the processing system on the deck of the offshore platform through the annular channel between the inner and outer pipes of the coaxial continuous oil pipe 16.
本发明所述的水合物为在一定温压条件下由甲烷等气体分子和水分子结合形成的笼型固体结晶体，沉积在海底泥质粉砂储层内。The hydrate described in the present invention is a cage-type solid crystal formed by the combination of gas molecules such as methane and water molecules under certain temperature and pressure conditions, and is deposited in the muddy silt sand reservoir on the seabed.
本发明通过向井下输送助燃剂，与地层产出的可燃气体混合后，利用高压电点火系统，完成井下原位燃烧加热，产生的热量破坏水合物形成的热力学条件，促进水合物快速分解，同时，燃烧后的废气降低了井筒的液柱压力，为井筒内液体举升提供了充足的动力，该方法为热激和降压法的联合应用，本发明天然气水合物开采工艺简单，开采效率高，成本低廉，操作简单，易于实现自动化和远程遥控，适用于海洋天然气水合物大规模工业化开采。The present invention delivers a combustion aid to the well, mixes it with the combustible gas produced by the formation, and then uses a high-voltage electric ignition system to complete in-situ combustion heating in the well. The heat generated destroys the thermodynamic conditions for the formation of hydrates and promotes the rapid decomposition of hydrates. At the same time, the exhaust gas after combustion reduces the liquid column pressure in the wellbore, providing sufficient power for lifting the liquid in the wellbore. This method is a combined application of thermal shock and pressure reduction methods. The natural gas hydrate exploitation process of the present invention is simple, has high exploitation efficiency, low cost, simple operation, and is easy to realize automation and remote control. It is suitable for large-scale industrial exploitation of marine natural gas hydrates.
此外，在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。尽管上面已经示出和描述了本发明的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本发明的限制，本领域的普通技术人员在本发明的范围内可以对上述实施例进行变化、修改、替换和变型。In addition, those skilled in the art may combine and combine the different embodiments or examples and the features of the different embodiments or examples described in this specification without contradiction. Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.
| Application Number | Priority Date | Filing Date | Title |
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| CN202210938360.0ACN115306364B (en) | 2022-08-05 | 2022-08-05 | A natural gas hydrate in-situ heating and drainage device and drainage method thereof |
| Application Number | Priority Date | Filing Date | Title |
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| CN202210938360.0ACN115306364B (en) | 2022-08-05 | 2022-08-05 | A natural gas hydrate in-situ heating and drainage device and drainage method thereof |
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| CN115306364A CN115306364A (en) | 2022-11-08 |
| CN115306364Btrue CN115306364B (en) | 2024-05-17 |
| Application Number | Title | Priority Date | Filing Date |
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| CN202210938360.0AActiveCN115306364B (en) | 2022-08-05 | 2022-08-05 | A natural gas hydrate in-situ heating and drainage device and drainage method thereof |
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| SAGD技术应用于陆域冻土天然气水合物开采中的理论研究;王志刚;张永勤;梁健;王汉宝;吴纪修;李宽;李鑫淼;尹浩;李小洋;;探矿工程(岩土钻掘工程);20170510(第05期);第14-18页* |
| 王汉鹏 等.地下盐穴储气库造腔控制与注采运行安全评估.山东大学出版社,2021,第29-33页.* |
| Publication number | Publication date |
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| CN115306364A (en) | 2022-11-08 |
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