CN215907827U - Combustible ice development and production well - Google Patents
Combustible ice development and production well Download PDFInfo
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- CN215907827U CN215907827U CN202121797043.9U CN202121797043U CN215907827U CN 215907827 U CN215907827 U CN 215907827U CN 202121797043 U CN202121797043 U CN 202121797043U CN 215907827 U CN215907827 U CN 215907827U
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Abstract
The utility model discloses a combustible ice development production well, wherein three second packers are arranged between a production casing and a production pipe of the production well at intervals up and down, an upper second annular cavity and a lower second annular cavity are formed by the production casing, the production pipe and two adjacent second packers, the production casing is provided with a third through hole group communicated with the inside of the upper second annular cavity, the third through hole group is positioned below a surface casing, the pipe wall of the production pipe is respectively provided with two groups of first through hole groups communicated with the insides of the upper second annular cavity and the lower second annular cavity, the pipe wall of the production pipe is provided with a fourth through hole group communicated with the inside of the production pipe, two one-way ball valves are arranged in the production pipe at intervals up and down, the combustible ice development production well can realize sand washing, in-situ sand discharge, keep the top stratum of combustible ice stable, prevent seawater from permeating into a combustible ice decomposition exploitation area and adjust the temperature and pressure of the decomposition area, the purpose of maintaining and controlling the continuous decomposition and exploitation of the combustible ice is achieved.
Description
Technical Field
The utility model belongs to the field of combustible ice development and production, and particularly relates to a combustible ice development and production well.
Background
Natural gas hydrate (commonly called as combustible ice) is formed by natural gas molecules (main component methane) and water molecules in a cage-shaped crystal structure under the environment of low temperature and high pressure, and the thickness of the natural gas hydrate is 1m under the condition of standard temperature and pressure3The full decomposition energy of the natural gas hydrate can be released to 150-180 m3The natural gas of (1). It is generally accepted that the geological reserves of global gas hydrates are about 2 x 1016m3The total amount of carbon-containing traditional fossil energy is twice that of the carbon-containing traditional fossil energy which is proved on land worldwide, and the shallow layer of the seabed is a natural gas hydrate main force occurrence area at the depth of 300-1500 m. In the development process of natural gas hydrate deposits, a solid-to-gas-liquid phase change inevitably occurs along with the decomposition process of natural gas hydrates. During the process, a large amount of flowable water, gas and bonded and weakened silt are generated, the supporting strength of a pore framework for storing the original solid-phase combustible ice is reduced, the bonding strength is weakened, the strength of a seabed shallow geological structure is also reduced, and meanwhile, under the action of driving pressure difference, the silt on the inner wall of the porous medium is continuously washed in the seepage and migration process of gas-water two-phase flow to a bottom hole jet hole, so that the doped silt is separated and separated out from the original position more and more, and is transported to the periphery of a production well or the well along with the seepage process of the gas-water two-phase flow to accumulate and cause blockage, thereby influencing production.
For the blocking phenomenon of the mud and sand, various sand control nets play a role in delaying, the problem cannot be solved completely and effectively, and finally the gas output can be reduced to influence the production. In the multiple test production of combustible ice natural gas in various countries in the world at present, the test production is forced to be shut down and terminated due to serious sand production problem. In addition, different from the traditional fossil energy development, the shallow region where the seabed combustible ice storage layer belongs is loose in geology, and the exploitation process of the seabed combustible ice storage layer is also accompanied with serious phenomena of liquefaction, disintegration and collapse of a large-area solid phase storage layer. Therefore, the decomposition and development of the natural gas hydrate may induce geological disasters such as instability of a seabed slope, stratum collapse, shallow depression and the like; particularly, due to the change of geological structure caused by exploitation, when a large amount of seawater permeates into a natural gas hydrate deposit exploitation area, the controllable decomposition of the natural gas hydrate is influenced, and finally, the control failure of the development and production process of the combustible ice is caused.
The development of safe, environment-friendly, efficient and economical production processes and technologies is required to ensure that the formation is stable, the temperature and pressure are controllable, the production is efficient and continuous, the environment is friendly, and the laws and standards of resource commercial development are met and met in the development process of natural gas hydrate deposits. The currently proposed exploitation technology of the natural gas hydrate in the shallow sea floor mainly comprises heat injection exploitation, replacement combined heating exploitation, depressurization exploitation, geological exploitation, depressurization and heating exploitation and the like. There are many key issues to be addressed in these current technologies. Wherein, the heat loss of the shaft is larger in the heat injection exploitation process; the pyrolysis radiation area is small in the microwave heating process; the geothermal exploitation limitation is strong; the replacement mining process has low replacement degree; the temperature control difficulty of replacement combined heating mining is high, and the construction process is complex; geological excavation mining has low energy efficiency and great damage to the stability of a seabed shallow layer. The above methods cannot avoid the problems of liquefaction of the combustible ice storage layer and serious sand production. If the two common problems cannot be effectively solved, the original reservoir geological structure is finally damaged and collapsed, seawater is also infiltrated along with the damage of the combustible ice reservoir, the production well is finally completely out of control, and even geological risks are induced.
SUMMERY OF THE UTILITY MODEL
In order to achieve the above objects, it is an object of the present invention to provide a combustible ice developing and producing well which can continuously, controllably, safely decompose and collect combustible ice.
In order to achieve the purpose, the technical scheme of the utility model is as follows: the utility model provides a combustible ice develops production well, includes underwater wellhead assembly, production sleeve pipe and production pipe, the production pipe is established in the production sleeve pipe, and forms annular cavity between the two, the upper end of production sleeve pipe and production pipe is equallyd divide do not with underwater wellhead assembly connects, the lower extreme of production pipe is less than the lower extreme of production sleeve pipe, production sleeve pipe with be equipped with three second packer of interval distribution from top to bottom between the production pipe, and adjacent two form a second toroidal cavity between the second packer be equipped with on the pipe wall of production sleeve pipe and be located the top the third through-hole group of intercommunication in the second toroidal cavity, two sets of first through-hole groups of interval distribution about being equipped with on the pipe wall of production pipe, two sets of first through-hole groups and two second toroidal cavities one-to-ones, every group first through-hole group respectively with correspond communicate in the second toroidal cavity, and the production pipe is provided with a through fourth through hole group on the pipe wall below the production casing pipe, two upper and lower interval distributions are arranged in the production pipe, the production pipe is provided with two separated one-way ball valves, the first through hole group below the production pipe is positioned between the two one-way ball valves, the one-way ball valves are used for avoiding the upward flow of materials or sand-water mixed liquid below the production pipe in the production pipe, a second injection pipe and a third injection pipe are arranged in the underwater wellhead device, the lower end of the second injection pipe is communicated with the second annular cavity above the second injection pipe, and the lower end of the third injection pipe is communicated with the second annular cavity below the third injection pipe.
The beneficial effects of the above technical scheme are that: the lower ends of the production casing and the production pipe are both put into a sand layer below a combustible ice storage layer of a seabed stratum, the lower end of the production casing is lower than the lower end of the production casing, the second injection pipe is used for injecting regulating gas into the second annular cavity positioned above, the regulating gas is nitrogen or natural gas after temperature and pressure regulation, the injected regulating gas enters the combustible ice storage layer through the third through hole group to regulate the temperature and pressure inside the combustible ice storage layer, and further the decomposition speed of the combustible ice is controlled, wherein when the regulating gas is injected, the upper end of the production pipe needs to be simultaneously regulated and controlled to pass through a passage of an underwater wellhead or a normally open valve is closed, the normally open valve is closed to prevent the injected regulating gas from flowing upwards in an uncontrolled manner after entering the production pipe through the first through hole group positioned above, and the natural gas obtained after decomposition possibly carries a small amount of sand and water to enter the second annular cavity positioned above through the third through hole group, the gas-sand liquid multiphase mixture entering the production pipe is separated in the production pipe, the gas flows upwards to an underwater wellhead through the production pipe (the outlet pressure at the upper end of the production pipe needs to be adjusted and a channel needs to be kept smooth during production), the silt and water entering the production pipe are accumulated and deposited downwards in the production pipe, a third injection pipe is used for injecting water into the second annular cavity positioned below at high pressure, the water injected into the production pipe flows into the production pipe through the first through hole group positioned below, the silt and water deposited in the production pipe are extruded and discharged out of the production pipe through the fourth through hole group, the two one-way ball valves can prevent the silt and water in the production pipe from going upwards through the production pipe, in addition, the whole production well can also wash the silt and clean the third through hole group which enter the second annular cavity positioned above, the second injection pipe is used for injecting water into the second annular cavity positioned above to wash and flush the silt in the second annular cavity positioned above through the first through hole group positioned above, and the normally-open valve can be closed during washing, so that the combustible ice development and production well can complete in-situ controllable decomposition of combustible ice in a reservoir stratum, in-situ gas-liquid-sand separation in the production well, cleaning of a production hole (namely a third through hole group), cleaning of silt in the well, discharging of the in-situ silt in the well and the like, thereby facilitating the regulation and control of geological stability, production conditions and production working conditions and ensuring continuous and stable production of combustible ice natural gas.
In the technical scheme, a normally open valve for separating the production pipe is further arranged in the production pipe, the two one-way ball valves are both positioned below the normally open valve, and the first through hole component positioned above is distributed between the normally open valve and the one-way ball valve positioned above.
The beneficial effects of the above technical scheme are that: when the third through hole group needs to be cleaned or the normally-open valve is closed in an emergency, the flushing liquid and the produced natural gas can be blocked from going upwards through the production pipe, and therefore production is suspended.
Still include the top casing among the above-mentioned technical scheme, the production sleeve pipe box is established in the top casing, and form annular cavity between the two, the sheathed tube lower extreme of production is less than top casing's lower extreme, top casing with interval distribution's first packer about being equipped with two between the production casing, top casing, production casing and two first packer is used for enclosing jointly and forms an inclosed first annular cavity, be equipped with on top casing's the pipe wall with the second through-hole group of intercommunication in the first annular cavity, two the second packer all is located top casing's below, the third through-hole group is located top casing's below, be provided with first filling tube among the wellhead assembly under water, the lower extreme of first filling tube with intercommunication in the first annular cavity.
The beneficial effects of the above technical scheme are that: the lower end of the surface casing is arranged below the inner upper part of the combustible ice reservoir, so that low-temperature liquid (low-temperature water or liquefied carbon dioxide) can be injected into the first annular cavity by using the first injection pipe, the low-temperature liquid entering the first annular cavity is extruded and diffused to the upper part of the combustible ice reservoir through the second through hole group, and the solid phase strength of combustible ice and newly generated carbon dioxide hydrate is enhanced in the combustible ice reservoir in the area near the second through hole group, so that the geological condition of the upper stratum of the combustible ice reservoir is more stable, and meanwhile, the infiltration of seawater into a natural gas production area in the combustible ice reservoir can be reduced or prevented.
The technical scheme includes that the underground wellhead device comprises a surface casing, a guide pipe arranged outside the surface casing, the upper end of the guide pipe is connected with the underground wellhead device, the lower end of the surface casing is lower than the lower end of the guide pipe, and the second through hole group is located below the guide pipe.
The beneficial effects of the above technical scheme are that: so make whole producing well obtain firm support and producing the peripheral stratum geological stability of well better, and the lower extreme of pipe is gone into in the overlying silt layer to the wellhead assembly provides firm support for the water.
In the technical scheme, the lower ends of the guide pipe, the surface casing pipe, the production casing pipe and the production pipe are respectively provided with a pipe shoe for anchoring in each stratum of the seabed.
The beneficial effects of the above technical scheme are that: this allows the conductor, surface casing, production casing and production pipe to be securely installed in place on the seabed.
The first packer located above in the above technical scheme is located below the conduit.
The beneficial effects of the above technical scheme are that: therefore, the whole first annular cavity is positioned below the guide pipe, the second through hole group is directly communicated with the combustible ice storage layer, and the low-temperature liquid extruded and flowing out through the second through hole group can diffuse and permeate into the combustible ice storage layer.
The second packer located above in the technical scheme is located below the surface casing.
The beneficial effects of the above technical scheme are that: so that the second annular cavity above is located below the surface casing, so that the second annular cavity above can be matched with the third through hole group, and the third through hole group penetrates through the production casing to enter the combustible ice reservoir outside the production casing.
In the technical scheme, the through holes of the second through hole group and/or the third through hole group are through holes, and the through holes of the fourth through hole group are through holes.
The beneficial effects of the above technical scheme are that: the perforation is adopted to manage and control the geological environment and the production conditions around the production well, so that the production of the combustible ice natural gas is more stable and durable.
In the above technical scheme, a sand control net or a screen is arranged at the second through hole group and/or the third through hole group (or the pipe section where the second through hole group and/or the third through hole group is located can be directly replaced by the screen according to the actual environmental conditions).
The beneficial effects of the above technical scheme are that: the sand control net or the screen can prevent sand grains with larger grain sizes from entering the second annular cavity.
Drawings
FIG. 1 is a schematic illustration of a combustible ice development production well according to an embodiment of the utility model;
FIG. 2 is a schematic view of another embodiment of a combustible ice development production well according to the present invention;
FIG. 3 is a distribution diagram of a surface casing, a production tubing and a conduit according to an embodiment of the present invention.
In the figure: the device comprises a 1 underwater wellhead device, a 2 surface casing, a 201 second through hole group, a 3 production casing, a 301 third through hole group, a 4 production pipe, a 401 first through hole group, a 402 fourth through hole group, a 5 first packer, a 6 second packer, a 7 one-way ball valve, an 8 first injection pipe, a 901 second injection pipe, a 902 third injection pipe, a 10 normally-open valve, an 11 guide pipe and a 12 pipe shoe.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the utility model.
Example 1
As shown in figure 1 (the seabed is represented by S in figure 1, the combustible ice storage layer is represented by B, the overlying silt layer above the combustible ice storage layer is represented by A, and the silt layer below the combustible ice storage layer is represented by C) and figure 3, the embodiment provides a combustible ice development and production well, which comprises an underwater wellhead device 1, and a guide pipe 11, a surface casing 2, a production casing 3 and a production pipe 4 which are sequentially sleeved from outside to inside, wherein annular spaces are formed among adjacent two layers of pipelines in the surface casing 2, the production casing 3 and the production pipe 4 (namely the outer diameter of the production pipe is smaller than that of the production casing, and the outer diameter of the production casing is smaller than that of the surface casing), the upper ends of the guide pipe 11, the surface casing 2, the production casing 3 and the production pipe 4 are respectively connected with the underwater wellhead device 1 (the upper ends of the guide pipe 11, the surface casing 2, the production casing and the production pipe 4 are respectively arranged inside the underwater wellhead device, The production casing 3 and the production pipe 4 are connected in a one-to-one correspondence manner, and the production casing and the production pipe belong to the existing oil gas productionWell production technology, which is not described herein) is connected, the depth of the lower ends of the conduit 11, the surface casing 2, the production casing 3 and the production pipe 4 going into the seabed formation is sequentially increased, two first packers 5 spaced up and down are arranged between the surface casing 2 and the production casing 3, the surface casing 2, the production casing 3 and the two first packers 5 are used for enclosing together to form a closed first annular cavity, a second through hole group 201 communicating the top formation of the combustible ice storage layer and the first annular cavity is arranged on the pipe wall of the surface casing 2, three second packers 6 spaced up and down are arranged between the production casing 3 and the production pipe 4, a second annular cavity is formed between the two adjacent second packers 6, and the two second packers 6 are both located below the surface casing 2, a third through hole group 301 communicated with the second annular cavity chamber above is arranged on the pipe wall of the production casing 3, the third through hole group 301 is positioned below the surface casing 2, two groups of first through hole groups 401 distributed at intervals are arranged on the pipe wall of the production casing 4, the two groups of first through hole groups 401 correspond to the two second annular cavities one by one, the first through hole groups of each group are respectively communicated with the corresponding second annular cavities, a fourth through hole group 402 communicated with the lower end of the production casing is arranged on the pipe wall of the production casing 4 below the production casing 3, the fourth through hole groups are both positioned in a mud-sand layer below the combustible ice storage layer, two unidirectional ball valves 7 distributed at intervals are arranged in the production casing 4 and separate the production casing, the unidirectional ball valve 7 positioned above is arranged between the two groups of the first through hole groups 401, the first through hole group 401 located below is arranged between the two one-way ball valves, the one-way ball valve 7 is used for preventing sand-liquid below the one-way ball valve from flowing upwards through the one-way ball valve 4, a first injection pipe 8, a second injection pipe 901 and a third injection pipe 902 are arranged in the underwater wellhead device 1, the lower end of the first injection pipe is communicated with the first annular cavity, the lower end of the second injection pipe is communicated with the second annular cavity located above, the lower end of the third injection pipe is communicated with the second annular cavity located below, wherein the first injection pipe is communicated with the first annular cavityThe pipe is used for injecting low-temperature liquid into the first annular cavity, and the low-temperature liquid is low-temperature seawater or liquefied CO2And the injected low-temperature liquid permeates and diffuses to the top stratum of the combustible ice storage layer through the second through hole group, so that stable CO is formed in the top stratum of the combustible ice storage layer2Hydrates and CH4The second injection pipe is used for injecting regulating gas into the second annular cavity positioned above the second injection pipe, and the regulating gas is N after temperature and pressure regulation2Or the natural gas, through adjusting the injection pressure (adjusting the pressure of the injection pump, or jointly adjusting the pressure of the production pipe in the underwater wellhead 1), the temperature and the pressure of the production area of the communicated combustible ice reservoir can be controlled, the purpose of controlling the speed of the decomposition of the combustible ice is achieved, the natural gas generated by the decomposed combustible ice enters the second annular cavity positioned above through the third through hole group, enters the production pipe through the first through hole group positioned above, ascends in the production pipe to become the produced and collected natural gas, a small amount of liquid and silt entering the production pipe along with the natural gas generated by the decomposition of the combustible ice accumulate and settle after entering the production pipe, and finally is extruded and discharged to a silt layer outside the production pipe through the fourth through hole group, namely, if necessary, the high-pressure water injection is carried out in the second annular cavity positioned below through the third injection pipe, the water injected into the production pipe can flow into the production pipe through the first through hole group, and the silt accumulated in the production pipe is extruded and discharged to a silt layer outside the production pipe through the fourth through hole group.
The combustible ice development and production well is convenient for production control, production cannot be hindered due to the sand production problem, and accordingly exploitation of combustible ice can be continuously and stably achieved.
In the above technical solution, a normally open valve 10 is further disposed in the production pipe 4 to separate the production pipe 4, the two check ball valves 7 are both located below the normally open valve 10, and the first through hole group 401 located above is distributed between the normally open valve 10 and the check ball valve 7 located above, so that in an emergency, production is suspended if necessary, or gas generated by decomposition of combustible ice is blocked from ascending through the production pipe, or the normally open valve is closed when the third through hole group 301 of the natural gas production area is cleaned.
In the above technical solution, the lower ends of the pipe walls of the guide pipe 11, the surface casing 2, the production casing 3 and the production pipe 4 are all provided with pipe shoes 12 for anchoring in respective strata, so that the guide pipe 11, the surface casing 2, the production casing 3 and the production pipe 4 can be stably installed in the respective strata.
In the above technical solution, the first packer 5 located above is disposed below the conduit 11, so that the second through hole set 201 connected to the first annular cavity is located below the conduit and in the combustible ice storage layer, and the volume of the first annular cavity is relatively smaller, which facilitates rapid injection of cryogenic liquid.
The second packer 6 above the above technical solution is located below the surface casing 2, so that the second annular cavity above the second packer is located below the surface casing, so that the volume of the second packer is smaller, and the second packer is convenient for quick operation.
As shown in fig. 3, the production tubing and production casing may also be designed as a non-vertical well with inclined and horizontal sections to meet the need for increased productivity.
In the actual engineering construction process of the production well, after partial installation procedures such as drilling, descending a guide pipe, well cementing and the like are completed, drilling is continuously carried out in the guide pipe and a surface casing is installed, wherein the requirement that the lower end of the surface casing is descended to the upper part in a combustible ice storage layer is met, so that second through hole groups on the surface casing are all positioned at the junction of the upper part of the combustible ice storage layer and an overlying sand layer, and the well cementing low-temperature surface casing is used for well cementingAfter cement slurry is completed, two first packers are arranged in a surface casing at intervals up and down (a second through hole group is positioned between the two first packers) and a first injection pipe with a coated heat insulation layer is arranged in the surface casing, and low-temperature liquid, such as low-temperature liquefied CO, is injected into the first annular cavity by using the first injection pipe2And is extruded and permeated to the upper end in the combustible ice storage layer through the second through hole group along with low-temperature CO2The continuous injection can not only maintain the original natural gas hydrate in a stable solid phase, but also form new CO with water in the overlying sand layer under the set temperature and pressure conditions2Hydrate, and then forming dense natural gas hydrate and CO in the upper part and boundary area in the combustible ice storage layer2Hydrate coating and the closer to the second set of through holes, natural gas hydrates with CO2The denser the hydrate covering layer is, the change of the geological stability at the top of the combustible ice storage layer is monitored by monitoring the change of temperature, pressure and geological conditions of the stratum, and the process is repeated as necessary to maintain or generate stable natural gas hydrate and CO2The hydrate covering layer is used for solidifying the sand layer, the geological stability in the drilling and production processes is maintained, and the seawater in the overlying sand layer is effectively reduced or prevented from permeating into the combustible ice storage layer.
Based on the operation and on the basis of completing the surface casing well cementation, continuously drilling a well in the surface casing, wherein the process can adopt a multi-well section combination in the vertical, inclined and/or horizontal directions as required, drilling the well to a sand layer below the combustible ice storage layer, then putting in and installing a production casing, and completing the well cementation (after well completion, three second packers are installed below the surface casing in the production casing at intervals up and down, and a sand prevention net is installed at a third through hole group on the production casing), after the well cementation of the production casing is completed, continuously drilling the well in the production casing, putting in the sand layer below the combustible ice storage layer, then putting in the production pipe, and respectively installing a normally open valve and a one-way ball valve at corresponding positions in the production pipe, and finally completing the well cementation and well completion.
During production, the normally open valve in the production pipe is opened, and depending on the production situation, if necessary, for example, the gas production rate deviates from normalSetting value, injecting temperature and pressure regulated N into the second annular cavity via the second injection pipe2Or the natural gas (the pressure regulating process needs to be completed by the pressure regulation coordination of the production pipe), namely the pressure reduction decomposition process of the production area of the combustible ice storage layer can be controlled, and further the gas production rate during the in-situ decomposition of the combustible ice is controlled, considering that the phase change of the natural gas hydrate can occur in the pressure reduction decomposition process of the combustible ice, the gas phase and the water phase are subjected to the driving pressure difference in the porous medium, so that the seepage in the combustible ice storage layer is caused, and the inner wall of the porous medium which is loose is washed along the way, and carry a small amount of silt and water into the production casing and finally into the production pipe, where they accumulate and deposit, then flows under the action of gravity and enters the lower end of the production pipe through the two one-way ball valves, when the silt is accumulated to a certain degree, the purified water can be injected by the third injection pipe to wash the silt in the production pipe and is extruded and discharged to the silt layer outside the production pipe through the fourth through hole group.
The first through hole group, the second through hole group, the third through hole group and the fourth through hole group are provided with at least one through hole.
Example 2
The present example provides a method of producing combustible ice natural gas using a combustible ice development production well according to example 1, comprising the steps of:
step 1: installing a combustible ice development and production well on the seabed in place, wherein the lower ends of the production pipe 4 and the production casing 3 are both lowered into a sand layer below a combustible ice storage layer, the lower end of the surface casing 2 is lowered into the combustible ice storage layer, the lower end of the guide pipe 11 is lowered into an overlying sand layer above the combustible ice storage layer, and the underwater wellhead device 1 is positioned above the seabed;
step 2: monitoring the geological stability of the stratum at the top of the combustible ice storage layer, if necessary, injecting low-temperature liquid (low-temperature seawater or liquid carbon dioxide or nitrogen) into the first annular cavity through the first injection pipe, extruding and permeating the injected low-temperature liquid into an area near a production well of the combustible ice storage layer through the second through hole group, maintaining the original solid-phase natural gas hydrate, generating new compact hydrate, maintaining and strengthening the solid-phase hydrate of the stratum at the top of the combustible ice storage layer, and reducing or preventing seawater from permeating into the combustible ice storage layer;
and step 3: injecting nitrogen or natural gas subjected to temperature and pressure regulation into the second annular cavity positioned above through an underwater wellhead and a second injection pipe according to requirements in the production process, allowing the injected gas to enter a combustible ice storage layer through the third through hole group so as to control the decomposition speed of the combustible ice in the combustible ice storage layer, allowing the decomposed natural gas to possibly carry a small amount of sand and water and allowing the sand and water to enter a production pipe through the third through hole group, the second annular cavity positioned above and the first through hole group positioned above, allowing the gas in the production pipe to flow upwards through the production pipe, and allowing the sand and water entering the production pipe to downwards accumulate and deposit through the two one-way ball valves;
and 4, step 4: purified water is injected into the second annular cavity below through the third injection pipe, the injected water enters the production pipe through the first through hole group below, mud and sand deposited at the lower end in the production pipe are pressurized and washed, and the mud and sand layer outside the production pipe is discharged through the fourth through hole group through extrusion so as to realize in-situ removal of the accumulated and deposited mud and sand in the production pipe.
Therefore, the geological stability of the top stratum of the combustible ice storage layer can be ensured, seawater is prevented or reduced from permeating into the combustible ice storage layer, and gas-sand-liquid separation, mud-sand cleaning, in-situ discharge and the like are realized.
The above-mentioned embodiments are only examples of the present invention, and should not be construed as limiting the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. The utility model provides a combustible ice develops production well, its characterized in that, includes underwater wellhead assembly (1), production sleeve pipe (3) and production pipe (4), the production pipe is established in the production sleeve pipe, and forms annular cavity between the two, the upper end of production sleeve pipe (3) and production pipe (4) is equallyd divide respectively with underwater wellhead assembly (1) is connected, the lower extreme of production pipe (4) is less than the lower extreme of production sleeve pipe (3), production sleeve pipe (3) with be equipped with three second packer (6) of interval distribution about between production pipe (4), and adjacent two form a second annular cavity between second packer (6) be equipped with on the pipe wall of production sleeve pipe (3) and be located the third through-hole group (301) that communicates in the second annular cavity, be equipped with two sets of first through-hole groups (401) of interval distribution about on the pipe wall of production pipe (4), the two groups of the first through hole groups correspond to the two second annular cavities one by one, each group of the through hole groups (401) is respectively communicated with the corresponding second annular cavities, the production pipe (4) is provided with a through fourth through hole group (402) on the pipe wall below the production casing pipe (3), two one-way ball valves (7) which are distributed at intervals up and down are arranged in the production pipe (4) and separate the production pipe, the first through hole group below the production pipe is positioned between the two one-way ball valves (7), the one-way ball valves (7) are used for preventing materials or sand-water below the production pipe (4) from flowing upwards through the one-way ball valves, the mixed liquid underwater wellhead device (1) is provided with a second injection pipe (901) and a third injection pipe (902), the lower end of the second injection pipe (901) is communicated with the second annular cavity above the mixed liquid wellhead device, the lower end of the third injection pipe (902) is communicated with the second annular cavity positioned below.
2. Combustible ice development production well according to claim 1, characterized in that inside the production pipe (4) there is also a normally open valve (10) separating the production pipe (4), both of the one-way ball valves (7) being located below the normally open valve (10), and the first set of through holes (401) located above being distributed between the normally open valve (10) and the one-way ball valve (7) located above.
3. The combustible ice development and production well according to claim 1 or 2, characterized by further comprising a surface casing (2), wherein the production casing (3) is sleeved in the surface casing (2) and an annular cavity is formed between the production casing and the surface casing (2), the lower end of the production casing (3) is lower than the lower end of the surface casing (2), two first packers (5) which are distributed at intervals up and down are arranged between the surface casing (2) and the production casing (3), the surface casing (2), the production casing (3) and the two first packers (5) are used for jointly enclosing to form a closed first annular cavity, a second through hole group (201) communicated with the first annular cavity is arranged on the wall of the surface casing (2), and the two second packers (6) are both positioned below the surface casing (2), the third through hole group is located below the surface casing pipe (2), a first injection pipe (8) is arranged in the underwater wellhead device (1), and the lower end of the first injection pipe (8) is communicated with the inside of the first annular cavity.
4. A combustible ice development production well according to claim 3, characterized by further comprising a conduit (11) arranged outside the surface casing (2), the upper end of the conduit (11) being connected to the subsea wellhead (1), the lower end of the surface casing (2) being lower than the lower end of the conduit (11), the second set of through holes (201) being located below the conduit (11).
5. A combustible ice development production well according to claim 4, characterized in that the lower ends of the outer walls of the conduit (11), surface casing (2), production casing (3) and production pipe (4) are each provided with a pipe shoe (12) for anchoring in the various formations on the seabed.
6. A combustible ice development production well according to claim 4, characterized in that the first packer (5) situated above is arranged below the conduit (11).
7. A combustible ice development production well according to claim 4, characterized in that the second packer (6) situated above is arranged below the surface casing (2).
8. A combustible ice development production well according to claim 4, characterized in that the through holes of the second and/or third set of through holes (201, 301) are perforations and the through holes of the fourth set of through holes are perforations.
9. A combustible ice development production well according to claim 8, characterized in that a sand control net or screen is provided at the second through hole group (201) and/or the third through hole group (301).
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| CN202121797043.9U CN215907827U (en) | 2021-08-03 | 2021-08-03 | Combustible ice development and production well |
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| CN202121797043.9U CN215907827U (en) | 2021-08-03 | 2021-08-03 | Combustible ice development and production well |
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