AU2020286197B2 - Coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation system and method - Google Patents
Coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation system and method Download PDFInfo
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- CCEKAJIANROZEO-UHFFFAOYSA-N sulfluramid Chemical group CCNS(=O)(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F CCEKAJIANROZEO-UHFFFAOYSA-N 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 title claims abstract description 38
- NMJORVOYSJLJGU-UHFFFAOYSA-N methane clathrate Chemical compound C.C.C.C.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O NMJORVOYSJLJGU-UHFFFAOYSA-N 0.000 title claims abstract description 23
- 239000007789 gas Substances 0.000 claims abstract description 94
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Natural products C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 81
- 238000009413 insulation Methods 0.000 claims abstract description 69
- 238000002955 isolation Methods 0.000 claims abstract description 64
- 150000004677 hydrates Chemical class 0.000 claims abstract description 52
- 239000003345 natural gas Substances 0.000 claims abstract description 39
- 238000010438 heat treatment Methods 0.000 claims abstract description 37
- 238000004519 manufacturing process Methods 0.000 claims abstract description 36
- -1 natural gas hydrates Chemical class 0.000 claims abstract description 13
- 238000003860 storage Methods 0.000 claims description 19
- 238000005553 drilling Methods 0.000 claims description 14
- 239000010425 asbestos Substances 0.000 claims description 13
- 229910052895 riebeckite Inorganic materials 0.000 claims description 13
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 10
- 239000004917 carbon fiber Substances 0.000 claims description 10
- 239000013049 sediment Substances 0.000 claims description 10
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 7
- 239000011888 foil Substances 0.000 claims description 7
- 230000005611 electricity Effects 0.000 claims description 4
- 230000007246 mechanism Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000011435 rock Substances 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract description 7
- 238000009412 basement excavation Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 230000007547 defect Effects 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 5
- 238000005065 mining Methods 0.000 description 5
- 238000010276 construction Methods 0.000 description 3
- 230000002265 prevention Effects 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 2
- 238000009933 burial Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000005243 fluidization Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000000844 transformation Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 206010039509 Scab Diseases 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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- 239000000835 fiber Substances 0.000 description 1
- 230000002068 genetic effect Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910052976 metal sulfide Inorganic materials 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- 239000004033 plastic Substances 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
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- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/01—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells specially adapted for obtaining from underwater installations
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
- E21B43/2401—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection by means of electricity
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
- E21B41/0099—Equipment or details not covered by groups E21B15/00 - E21B40/00 specially adapted for drilling for or production of natural hydrate or clathrate gas reservoirs; Drilling through or monitoring of formations containing gas hydrates or clathrates
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
The invention discloses a coverage-type deep-sea mud volcano-associated natural gas
hydrate exploitation system and method, which are mainly applied to submarine mud
volcano-associated superficial massive hydrates and exploit natural gas hydrates through a
coverage-type heat-insulation heating method according to the occurrence characteristics
of deep-sea mud volcano-associated hydrates, based on a specially-designed gas isolation
and heat insulation cover and thermal electrodes. Decomposed hydrates flow into a
production well via perforated holes of the production well under the effect of a pressure
difference at the bottom of the well, and a depressurization device is disposed in the
production well to further decompose the hydrates. This technical solution can effectively
overcome the defects of small heating range, high energy consumption and low output rate
of a heating-type hydrate exploitation method, greatly improve the exploitation efficiency
and effectively avoid possible environmental risks and eco-catastrophes caused by
large-area excavation on the seabed of existing methods; in addition, solar energy is used
on the site, so that the cost is low, environmental friendliness is realized, large-scale
efficient and economical exploitation of the hydrates is realized, the application prospect
is broad, and the application value is high.
Sea level
6 mud volcano
U 2 16
FIG. 1
&G 152
FIG. 2
Description
Sea level
6 mud volcano
U 2 16
FIG. 1
&G 152
FIG. 2
[0001] Technical Field
[0002] The invention belongs to the technical field of exploration and exploitation of
submarine natural gas hydrate resources, in particular to a coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system and method.
[0003] Description of Related Art
[0004] Natural gas hydrates (also referred to as "combustible ice") are ice-like
crystalline compounds formed by hydrocarbon gases such as methane and water in a
high-pressure environment. Natural gas hydrates in the sea include deep diffused natural gas
hydrates and superficial leaky natural gas hydrates according to the gas migration and
accumulation manner, the burial depth and the genetic model. Wherein, the superficial leaky
hydrates are closely associated with many special geologic bodies such as mud diaper, mud
volcanoes and gas chimneys.
[0005] Superficial hydrates associated with mud volcanoes are well developed in
many sea areas, and these mud volcanoes with a diameter of several meters to hundreds of
meters protrude over the seabed by several meters to tens of meters and are rich of huge
high-saturability hydrates. According to investigation, the reservoir of methane in a single
mud volcano in Nankai Trough reaches one billion cubic meters, and tens to hundreds of such
mud volcanoes are usually developed in groups. For example, 1742 superficial hydrate
geologic bodies have been found in Japan sea, and most of these superficial hydrate geologic
bodies are associated with mud volcanoes. Mud volcano-associated superficial hydrates are
expected to play the same important role as the deep diffused hydrates in hydrate industrialization because of their extensive distribution on the seabed, small burial depth and thick and laminar occurrence manner, and have immeasurable resource significance.
[0006] At present, many superficial hydrate exploitation methods have been put
forward, such as the well-known solid fluidization method and the robot mining method.
However, no corresponding method is available yet for superficial hydrates associated with
mud volcanoes. Meanwhile, although the solid fluidization method is simple and practicable,
large-area excavation needs to be carried out on the seabed, which may result in
eco-catastrophes and environmental disasters in a wide region, so the risk is uncontrollable.
The robot mining method may also result in environmental risks due to seabed excavation in
spite of its novel idea, and because of the high technical difficulties and other difficulties of
robot mining, it has not yet been implemented up to now in the seabed mining field including
exploration of submarine manganese nodule crusts and metal sulfide, which indicates that the
seabed robot is still a conceptual design for current mining and remains far off being put into
industrial production.
[0007] Considering the special structures of the deep-sea mud volcano-associated
natural gas hydrates such as shallow occurrence positions and even exposure to the surface of
the seabed, centralized occurrence scopes, moundy tops protruding out of the surface of the
seabed, and gas channels developed at the center, there is an urgent need for a targeted
exploitation technique.
[0008] The invention provides a coverage-type deep-sea mud volcano-associated
natural gas hydrate exploitation system and method, which are mainly applied to submarine
mud volcano-associated superficial massive hydrates and adopt a coverage-type
heat-insulation heating method to exploit the hydrates according to the occurrence characteristics of the deep-sea mud volcano-associated hydrates.
[0009] The invention is realized through the following technical solution:
[0010] A coverage-type deep-sea mud volcano-associated natural gas hydrate
exploitation system comprises an engineering ship support unit, a power supply unit, a
drilling and casing unit and a gas isolation and heat insulation unit, wherein the engineering
ship support unit provides basic hardware support for hydrate exploitation and realizes a
collection of natural gas hydrates, and the power supply unit is connected to the gas isolation
and heat insulation unit through a power supply cable;
[0011] The gas isolation and heat insulation unit is regularly laid on a mud volcano
, covers the mud volcano and comprises a gas isolation and heat insulation cover connected to
the power supply unit, wherein the gas isolationandheatinsulation cover sequentially
comprises, from bottom to top, a heat-conducting aluminum foil layer, a carbon fiber heating
wire layer, an asbestos heat insulation layer and a heat-proof gas isolation layer and supplies
heat into a sediment layer to heat a natural gas hydrate reservoir.
[0012] Furthermore, the gas isolation and heat insulation unit further comprises
thermal electrodes which are disposed at positions with a high hydrate saturability and a large
thickness, the thermal electrodes and the carbon fiber heating wire layer of the gas isolation
and heat insulation cover adopt two independent power supply circuits, and the power supply
circuit of the thermal electrodes is separately buried between the asbestos heat insulation layer
and the heat-proof gas isolation layer.
[0013] Furthermore, a safe unhooking system is disposed at a joint of an exploitation
mother ship and the natural gas transport pipe to handle a sudden severe weather or other
disastrous events to avoid risks and guarantee operation safety.
[0014] Furthermore, the power supply unit comprises a solar heating panel, a
photoelectric converter and a storage battery which are disposed on the engineering ship support unit, and solar energy or electricity in the storage battery is transmitted into the gas isolation and heat insulation cover and the thermal electrodes through the power supply unit to heat the hydrates.
[0015] Furthermore, the engineering ship support unit comprises the exploitation
mother ship, a hoisting mechanism and a natural gas storage device, a flow control valve is
disposed on the natural gas storage device, a temperature-pressure sensor is disposed on the
power supply cable, and the operating state of the system is determined and controlled
according to system information collected by the temperature-pressure sensor and the flow
control valve, so that safe and efficient operation of the system is guaranteed.
[0016] The invention further provides an exploitation method based on the
coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation system,
comprising the following steps:
[0017] First, determining a central conduit of the mud volcano, drilling a well in the
central conduit of the mud volcano, and disposing a casing pipe and perforated holes in the
central conduit of the mud volcano;
[0018] Second, disposing the gas isolation and heat insulation unit on a flank of the
mud volcano, wherein the gas isolation and heat insulation unit comprises the gas isolation
and heat insulation cover and thermal electrodes, and the gas isolation and heat insulation
cover sequentially comprises, from bottom to top, a heat-conducting aluminum foil layer, the
carbon fiber heating wire layer, the asbestos heat insulation layer and the heat-proof gas
isolation layer;
[0019] Third, heating hydrates by means of the ship-borne power supply unit; and
[0020] Fourth, collecting gas in the production well, and storing the collected gas on
an engineering ship.
[0021] Furthermore, in the first step, the position of the central conduit of the mud volcano is targeted according to the position of a cold spring vent determined by a two-dimensional multi-channel seismic section explanation result and a submarine image.
[0022] Furthermore, the first step is implemented specifically through the following
sub-steps:
[0023] Drilling the well in the central conduit of the mud volcano through a deepwater
drilling technique, wherein the drilled well penetrates through a sediment covering layer
above natural gas, stretches into a hydrate reservoir and ends at bed rock of the mud volcano,
so that the production well is formed; and
[0024] Mounting the casing pipe, forming the perforated holes in the hydrate reservoir
to guide water and gas generated by decomposing the hydrates, and disposing the
depressurization control valve in the production well to combine heat production and
depressurization to decompose the hydrates more sufficiently.
[0025] Furthermore, the second step is implemented specifically through the
following steps:
[0026] Drilling holes at position, with a high hydrate saturability and a large thickness,
of the flank of the mud volcano, and placing the thermal electrodes in the holes;
[0027] then, regularly placing the gas isolation and heat insulation cover on the mud
volcano by means of an engineering underwater robot, and connecting the gas isolation and
heat insulation cover to the thermal electrodes placed in the drilled holes, wherein an opening
is formed in a position, corresponding to a central hole of the mud volcano, of the gas
isolation and heat insulation cover.
[0028] Furthermore, in the fourth step, after gas released by the hydrates flows into
the production well via the perforated holes, the gas is delivered into a natural gas storage
device on an exploitation mother ship through the natural gas transport pipe, and a safe
unhooking system is disposed at a joint of the natural gas transport pipe and the exploitation mother ship to handle a sudden severe weather or other disastrous events.
[0029] Compared with the prior art, the invention has the following advantages and
beneficial effects:
[0030] 1) The gas isolation and heat insulation cover can be laid freely according to
the shape of the mud volcano, has a good gas leakage prevention capacity to prevent gas
generated by decomposing the hydrates from leaking from the flank, and can realize uniform
heating; heat-insulation treatment is carried out between the gas isolation layer and the
heating layer with asbestos materials, so that the heating layer only supplies heat to the
hydrates below to minimize energy consumption;
[0031] 2) Moreover, multiple thermal electrodes are disposed at the position with a
high hydrate saturability and a large thickness and are effectively connected to heating
elements of the gas isolation and heat insulation cover, and each thermal electrode can
penetrate to a required depth according to the actual depth of the hydrates to further heat the
hydrates in a target region, so that the decomposed hydrates can flow into the production well
via the perforated holes of the production well under the effect of a pressure difference at the
bottom of the well.
[0032] By adoption of this solution, the defects of small heating range, high energy
consumption and low output rate of a heating-type hydrate exploitation method are overcome,
and the exploitation efficiency can be greatly improved; moreover, possible environmental
risks and eco-catastrophes caused by large-area excavation on the seabed of existing methods
are avoided; large-scale efficient and economical exploitation of the hydrates can be realized,
the application prospect is broad, and the application value is high.
[0033] FIG. 1 is a schematic diagram of a coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation system in an embodiment of the invention;
[0034] FIG. 2 is a structural diagram of a gas isolation and heat insulation cover in an
embodiment of the invention;
[0035] Wherein: 1, exploitation mother ship; 2, hoisting mechanism; 3, natural gas
storage device; 4, flow control valve; 5, solar heating panel; 6, photoelectric converter; 7,
storage battery; 8, safe unhooking system; 9, temperature-pressure sensor; 10, power supply
cable; 11, production well; 12, perforated hole; 13, depressurization control valve; 14, natural
gas transport pipe; 15, gas isolation and heat insulation cover; 16, thermal electrode; 17,
hydrate reservoir; 18, sediment layer; 151, heat-conducting aluminum foil layer; 152, carbon
fiber heating wire layer; 153, asbestos heat insulation layer; 154, heat-proof gas isolation
layer.
[0036] To gain a clearer understanding of the above purposes, features and advantages
of the invention, the invention will be further explained below in conjunction with the
drawings and embodiments. Many specific details are expounded in the following description
for a comprehensive appreciation of the invention. But the invention can also be implemented
in other ways different from those mentioned herein. Therefore, the invention is not limited to
the specific embodiments disclosed below.
[0037] The invention provides a coverage-type deep-sea mud volcano-associated
natural gas hydrate exploitation system and method, which are mainly applied to submarine
mud volcano-associated superficial massive hydrates and exploit natural gas hydrates through
a heating method based on a specially-designed gas isolation and heat insulation cover and
thermal electrodes. Decomposed hydrates flow into a production well via perforated holes of the production well under the effect of a pressure difference at the bottom of the well, and a depressurization device is disposed in the production well to further decompose the hydrates to complete thermal production of the volcano-associated hydrates; moreover, to reduce energy consumption and improve economical efficiency, solar power generation is used to heat the thermal electrodes, and a ship-borne autonomous power supply device is used in rainy days or at night when the solar energy conversion efficiency is insufficient, so that stable and continuous production is guaranteed.
[0038] Embodiment 1
[0039] This embodiment provides a coverage-type exploitation system for thermal
production of submarine deep-sea mud volcano-associated natural gas hydrates. When it is
determined in the resource exploration stage that a hydrate reservoir 17 in a submarine mud
volcano is located below a sediment layer 18, this system and relevant techniques can be used
to exploit hydrates to obtain natural gas. Specifically, as shown in FIG. 1:
[0040] The exploitation system comprises an engineering ship support unit, a power
supply unit, a drilling and casing unit and a gas isolation and heat insulation unit, wherein the
engineering ship support unit comprises an exploitation mother ship 1, a hoisting mechanism
2, a natural gas storage device 3 and a safe unhooking system 8, a flow control valve 4 is
disposed on the natural gas storage device 3, and the safe unhooking system is able to
immediately separate the exploitation mother ship from other underwater systems in case of a
sudden severe weather or other disastrous events to allow the exploitation mother ship to
leave a working site to avoid risks and allow other systems to stay on a seabed; after the
weather returns to normal or the disastrous events are eliminated, the exploitation mother ship
can return to the site and continue to work after being connected to the underwater systems
through an unhooking device.
[0041] The power supply unit comprises a solar heating panel 5, a photoelectric converter 6 and a storage battery 7 which are disposed on the engineering ship support unit, the power supply unit is connected to the gas isolation and heat insulation unit through a power supply cable 10, a temperature-pressure sensor 9 is disposed on the power supply cable
, solar energy or electricity in the storage battery is transmitted into the gas isolation and
heat insulation cover and thermal electrodes through the power supply unit to heat the
hydrates, and system information is automatically collected by the temperature-pressure
sensor 9 and the flow control valve 4 to determine the operating state of the system and to
control the operation of a valve in time to guarantee safe and efficient operation of the system;
[0042] The drilling and casing unit comprises a production well 11, perforated holes
12 and a natural gas transport pipe 14, wherein the perforated holes 12 are formed in a hydrate
enrichment layer in the production well 11 to better guide the hydrates to release fluid, and a
depressurization control valve 13 is disposed at an appropriate position of the natural gas
transport pipe 14 to combine pressurization and thermal production to guarantee smooth
output of the natural gas hydrates. A well is preferably drilled in a central conduit of the mud
volcano, which is an important passage for material exchange between mud volcano fluid and
the outside and has a good lateral circulation condition; after the hydrates are heated to be
decomposed, gas will migrate into the central conduit to be collected; and specifically, the
position of the central conduit of the mud volcano can be targeted according to the position of
a cold spring vent determined by a two-dimensional multi-channel seismic section
explanation result and a submarine image.
[0043] The gas isolation and heat insulation unit can only supply heat into the
sediment layer, including the gas isolation and heat insulation cover 15 and the thermal
electrodes 16; the gas isolation and heat insulation cover 15 is a special heating body and
sequentially comprises, from bottom to top, a heat-conducting aluminum foil layer 151, a
carbon fiber heating wire layer 152, an asbestos heat insulation layer 153 and a heat-proof gas isolation layer 154. The heat-conducting aluminum foil layer 151 has a flame-retarding and heat-conducting function, thus facilitating heat transfer to the sediment layer below; the carbon fiber heating wire 152 is made of carbon fiber materials and is disposed in the gas isolation and heat insulation cover in an S shape, a hollow square shape or a wavy shape; the asbestos heat insulation layer 153 is subjected to heat-insulation treatment with asbestos materials to supply heat only into the sediment layer to efficiently and uniformly heat the natural gas hydrate reservoir; a heat-proof plastic film (made of polysulfone plastic and capable of being used under 100-180°C for a long time) is laid on the surface of the heat-insulating asbestos layer to serve as the heat-proof gas isolation layer 154 to endow the device with a gas leakage prevention function, so that gas generated by decomposing the hydrates will not leak to the ocean or the atmosphere via a covering layer; moreover, the four layers have food flexibility and can be bent freely according to the shape of the mud volcano without compromising the using effect.
[0044] In addition, to avoid contradictions that may be caused by different heating
powers, the thermal electrodes 16 and carbon fiber heating wires of the gas isolation and heat
insulation cover 15 adopt independent power supply circuits; during construction, the circuit
of the thermal electrodes is separately buried between the heat insulation layer and the gas
isolation layer of the gas isolation and heat insulation cover 15, so that an opening does not
need to be additionally formed in the gas isolation and heat insulation cover 15 anymore, the
construction difficulty will not be increased, and the risk of gas leakage is avoided; during
exploitation, power is supplied to the thermal electrodes separately, and the heating efficiency
is controlled through a temperature control switch to satisfy the heating requirements of
hydrates with different thicknesses.
[0045] According to this embodiment, a coverage-type heat-insulation heating method
is adopted according to the occurrence characteristics of deep-sea mud volcano hydrates; the gas isolation and heat insulation cover can be laid freely according to the shape of the mud volcano, has a good gas leakage prevention capacity to prevent gas generated by decomposing the hydrates n from leaking from the flank, and can realize uniform heating; heat-insulation treatment is carried out between the gas isolation layer and the heating layer with asbestos materials, so that the heating layer only supplies heat to the hydrates below to minimize energy consumption; moreover, multiple thermal electrodes are disposed at the position with a high hydrate saturability and a large thickness and are effectively connected to heating elements of the gas isolation and heat insulation cover, and each thermal electrode can penetrate to a required depth according to the actual depth of the hydrates to further heat the hydrates in a target region, so that the decomposed hydrates can flow into the production well via the perforated holes of the production well under the effect of a pressure difference at the bottom of the well.
[0046] Embodiment 2
[0047] This embodiment provides a corresponding exploitation method based on the
coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation system
disclosed in Embodiment 1. The exploitation method specifically comprises the following
steps:
[0048] First, the central conduit of the mud volcano is determined, a well is drilled in
the central conduit of the mud volcano, and a casing pipe and the perforated holes are
disposed in the central conduit of the mud volcano;
[0049] The exploitation mother ship 1 is sailed to the hydrate region of the mud
volcano, the well is drilled in the conduit of the mud volcano-associated hydrates through a
deepwater drilling technique, and the well penetrates through a sediment covering layer 18
above natural gas, stretches into a hydrate reservoir 17 and finally ends at bed rock of the mud
volcano, so that the production well 11 is formed; then the casing pipe is mounted, the perforated holes 12 are drilled in the hydrate reservoir to guide water and gas generated by decomposing the hydrates, and the depressurization control valve 13 is disposed in the production well, so that thermal production and decompression are combined to decompose the hydrates more sufficiently.
[0050] Second, the gas isolation and heat insulation cover is disposed on the flank of
the mud volcano by means of an engineering robot;
[0051] Holes are drilled in positions, with a high hydrate saturability and a large
thickness, of the flank of the mud volcano, and the thermal electrodes 16 are placed into the
holes. Then, the gas isolation and heat insulation cover 15 is regularly disposed on the mud
volcano by means of the engineering underwater robot and is connected to the thermal
electrodes 16 placed into the holes. An opening is formed in the position, corresponding to a
central hole of the mud volcano, of the gas isolation and heat insulation cover 15. In this way,
construction of the gas isolation and heat insulation unit is completed.
[0052] Third, the hydrates are heated by the ship-borne power supply unit (the solar
panel and the standby storage battery);
[0053] Solar energy collected by the solar heating panel 5 of the exploitation mother
ship 1 is converted into electric energy by the photoelectric converter 6, and the electric
energy is transmitted to the volcano gas isolation and heat insulation cover 15 on the seabed.
The gas isolation and heat insulation 15 and the integrated thermal electrodes 16 supply
power to heat the natural gas hydrates. In rainy days or at night when the power of electric
energy generated by the whole solar system cannot meet exploitation requirements, the
ship-borne storage battery 7 is started to supply power to guarantee that the whole production
process is stable and continuous.
[0054] Fourth, gas in the production well is collected and is stored on the ship;
[0055] After gas released by the hydrates flows into the production well 11 via the perforated holes 12, the gas can be delivered into the natural gas storage device 3 on the exploitation mother ship through the natural gas transport pipe 14 so as to be stored. The depressurization control valve 13 is disposed on the natural gas transport pipe, so that the risk of instrument damage caused by an excessively high pressure in the gas accumulation process is prevented; the pressure can be decreased properly to combine thermal production and depressurization to prompt the hydrate exploitation efficiency to be improved.
[0056] It should be noted that in the whole exploitation process, the full-course
operation is safety monitored by means of automatic control and feedback of the entire system.
For example, system information is automatically collected by the temperature-pressure
sensor 9 and the flow control valve 4 to determine the operating state of the system and to
control the operation of the valve in time to switch the operating mode, so that the working
requirements under different conditions are met, and safe and efficient operation of the system
is guaranteed.
[0057] According to the invention, a coverage-type heat-insulation heating method is
adopted according to the occurrence characteristics of deep-sea mud volcano hydrates, so that
the defects of small heating range, high energy consumption and low output rate of a
heating-type hydrate exploitation method are overcome, and the exploitation efficiency can be
greatly improved; moreover, possible environmental risks and eco-catastrophes caused by
large-area excavation on the seabed of existing methods are avoided; in addition, solar energy
is used on the site, so that the cost is low, environmental friendliness is realized, and in use,
the system is driven by standby electricity stored on the ship at night and in rainy days by
controlling the pressure condition of the gas well. By adoption of these measures, large-scale
efficient and economical exploitation of the hydrates can be realized, and the application
prospect is broad.
[0058] The aforesaid embodiments are merely preferred ones of the invention and are not intended to limit the invention in any forms. Any skilled in the art can make alterations or transformations according to the technical contents disclosed above to obtain equivalent embodiments applied to other fields. Any simple modifications and equivalent alternations and transformations of the above embodiments obtained based on the technical principle of the invention without departing from the contents of the technical solution of the invention still fall within the protection scope of the technical solution of the invention.
[0059] It will be understood that the term "comprise" and any of its derivatives (eg
comprises, comprising) as used in this specification is to be taken to be inclusive of features
to which it refers, and is not meant to exclude the presence of any additional features unless
otherwise stated or implied.
[0060] The reference to any prior art in this specification is not, and should not be taken as,
an acknowledgement or any form of suggestion that such prior art forms part of the common
general knowledge.
Claims (9)
1. A coverage-type deep-sea mud volcano-associated natural gas hydrate exploitation
system, comprising an engineering ship support unit, a power supply unit, a drilling and
casing unit and a gas isolation and heat insulation unit, wherein the engineering ship
support unit provides basic hardware support for hydrate exploitation and realizes a
collection of natural gas hydrates, and the power supply unit is connected to the gas
isolation and heat insulation unit through a power supply cable (10);
the drilling and casing unit comprises a production well (11), perforated holes (12) and
a natural gas transport pipe (14), wherein the perforated holes (12) are formed in a hydrate
enrichment layer in the production well (11), the natural gas transport pipe (14) has an end
disposed in the production well (11) and an end connected to the engineering ship support
unit, and a depressurization control valve (13) is disposed on the natural gas transport pipe
(14);
the gas isolation and heat insulation unit is regularly laid on a mud volcano, covers the
mud volcano and comprises a gas isolation and heat insulation cover (15) connected to the
power supply unit, wherein the gas isolation and heat insulation cover (15) sequentially
comprises, from bottom to top, a heat-conducting aluminum foil layer (151), a carbon
fiber heating wire layer (152), an asbestos heat insulation layer (153) and a heat-proof gas
isolation layer (154) and supplies heat into a sediment layer to heat a natural gas hydrate
reservoir;
the gas isolation and heat insulation unit further comprises thermal electrodes (16)
which are disposed at positions with a high hydrate saturability and a large thickness, the
thermal electrodes (16) and the carbon fiber heating wire layer (152) adopt two
independent power supply circuits, and the power supply circuit of the thermal electrodes
(16) is separately buried between the asbestos heat insulation layer (153) and the
heat-proof gas isolation layer (154).
2. The coverage-type deep-sea mud volcano-associated natural gas hydrate
exploitation system according to Claim 1, wherein a safe unhooking system (8) is
disposed at a joint of an exploitation mother ship (1) and the natural gas transport pipe (14)
to handle a sudden severe weather or other disastrous events.
3. The coverage-type deep-sea mud volcano-associated natural gas hydrate
exploitation system according to Claim 1, wherein the power supply unit comprises a solar
heating panel (5), a photoelectric converter (6) and a storage battery (7) which are
disposed on the engineering ship support unit, and solar energy or electricity in the storage
battery is transmitted into the gas isolation and heat insulation cover (15) and the thermal
electrodes (16) through the power supply unit to heat the hydrates.
4. The coverage-type deep-sea mud volcano-associated natural gas hydrate
exploitation system according to Claim 2, wherein the engineering ship support unit
comprises the exploitation mother ship (1), a hoisting mechanism (2) and a natural gas
storage device (3), a flow control valve (4) is disposed on the natural gas storage device
(3), a temperature-pressure sensor (9) is disposed on the power supply cable (10), and an
operating state of the system is determined and controlled according to system information
collected by the temperature-pressure sensor (9) and the flow control valve (4).
5. An exploitation method based on the coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system according to Claim 1,
comprising the following steps:
1) determining a central conduit of the mud volcano, drilling a well in the central
conduit of the mud volcano, and disposing a casing pipe and the perforated holes in the
central conduit of the mud volcano;
2) disposing the gas isolation and heat insulation unit on a flank of the mud volcano,
wherein the gas isolation and heat insulation unit comprises the gas isolation and heat
insulation cover (15) and the thermal electrodes (16), and the gas isolation and heat insulation cover (15) sequentially comprises, from bottom to top, the heat-conducting aluminum foil layer (151), the carbon fiber heating wire layer (152), the asbestos heat insulation layer(153) and the heat-proof gas isolation layer (154);
3) heating the hydrates by means of the ship-borne power supply unit; and
4) collecting gas in the production well, and storing the collected gas on an
engineering ship.
6. The exploitation method based on the coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system according to Claim 5, wherein
in Step 1), the position of the central conduit of the mud volcano is targeted according to
the position of a cold spring vent determined by a two-dimensional multi-channel seismic
section explanation result and a submarine image.
7. The exploitation method based on the coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system according to Claim 5, wherein
Step 1) is implemented specifically through the following sub-steps:
drilling the well in the central conduit of the mud volcano through a deepwater drilling
technique, wherein the drilled well penetrates through a sediment covering layer (18)
above natural gas, stretches into a hydrate reservoir (17) and ends at bed rock of the mud
volcano, so that the production well (11) is formed; and
mounting the casing pipe, forming the perforated holes (12) in the hydrate reservoir to
guide water and gas generated by decomposing the hydrates, and disposing the
depressurization control valve (13) in the production well (11) to combine heat production
and depressurization to decompose the hydrates more sufficiently.
8. The exploitation method based on the coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system according to Claim 5, wherein
Step 2) is implemented specifically through the following sub-steps:
drilling holes at position, with a high hydrate saturability and a large thickness, of the flank of the mud volcano, and placing the thermal electrodes (16) in the holes; then, regularly placing the gas isolation and heat insulation cover (15) on the mud volcano by means of an engineering underwater robot, and connecting the gas isolation and heat insulation cover (15) to the thermal electrodes (16) placed in the drilled holes, wherein an opening is formed in a position, corresponding to a central hole of the mud volcano, of the gas isolation and heat insulation cover (15).
9. The exploitation method based on the coverage-type deep-sea mud
volcano-associated natural gas hydrate exploitation system according to Claim 5, wherein
in Step 4), after gas released by the hydrates flows into the production well (11) via the
perforated holes (12), the gas is delivered into a natural gas storage device (3) on an
exploitation mother ship through the natural gas transport pipe (14), and a safe unhooking
system (8) is disposed at a joint of the natural gas transport pipe (14) and the exploitation
mother ship to handle a sudden severe weather or other disastrous events.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010159725.0 | 2020-03-09 | ||
| CN202010159725.0A CN111155972B (en) | 2020-03-09 | 2020-03-09 | Covering type deep-sea mud volcanic type natural gas hydrate exploitation system and method |
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| AU2020286197A1 AU2020286197A1 (en) | 2021-09-23 |
| AU2020286197B2 true AU2020286197B2 (en) | 2021-11-04 |
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| EP (1) | EP3879069B1 (en) |
| JP (1) | JP6892177B1 (en) |
| CN (1) | CN111155972B (en) |
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| WO2022248998A1 (en) * | 2021-05-25 | 2022-12-01 | Aarbakke Innovation As | Water bottom deployable gas hydrate production system |
| CN114708780B (en) * | 2022-05-12 | 2023-02-24 | 青岛海洋地质研究所 | Physical simulation experiment device and method for volcano formation |
| CN115182705B (en) * | 2022-07-27 | 2024-03-22 | 广东中煤江南工程勘测设计有限公司 | Submarine cold spring exploitation device and method |
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|---|---|---|---|---|
| WO2013025644A1 (en) * | 2011-08-12 | 2013-02-21 | Mcalister Technologies, Llc | Systems and methods for extracting and processing gases from submerged sources |
| CN108643869A (en) * | 2018-04-24 | 2018-10-12 | 西南石油大学 | A kind of sea-bottom shallow gas hydrates solid state fluidizing lasting exploit device and method |
| CN110630269A (en) * | 2019-10-12 | 2019-12-31 | 广州海洋地质调查局 | Natural gas collection system suitable for seabed mud volcano |
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| JP3305280B2 (en) * | 1999-03-29 | 2002-07-22 | 太陽工業株式会社 | How to collect methane hydrate gas |
| US8869880B2 (en) * | 2007-02-12 | 2014-10-28 | Gaumer Company, Inc. | System for subsea extraction of gaseous materials from, and prevention, of hydrates |
| CN105840148B (en) * | 2016-03-24 | 2019-01-01 | 西南石油大学 | The sea-bottom natural gas collection device and method of outer buoyancy tank ladder pipe circulating hot water heating |
| CN105822267B (en) * | 2016-03-31 | 2021-01-26 | 杨溢 | Method and device for exploiting deep sea natural gas hydrate |
| CN106884627B (en) * | 2017-03-28 | 2019-03-26 | 中国石油大学(华东) | A kind of sea bed gas hydrate quarrying apparatus |
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- 2020-12-04 DK DK20211931.9T patent/DK3879069T3/en active
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013025644A1 (en) * | 2011-08-12 | 2013-02-21 | Mcalister Technologies, Llc | Systems and methods for extracting and processing gases from submerged sources |
| CN108643869A (en) * | 2018-04-24 | 2018-10-12 | 西南石油大学 | A kind of sea-bottom shallow gas hydrates solid state fluidizing lasting exploit device and method |
| CN110630269A (en) * | 2019-10-12 | 2019-12-31 | 广州海洋地质调查局 | Natural gas collection system suitable for seabed mud volcano |
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| EP3879069A1 (en) | 2021-09-15 |
| AU2020286197A1 (en) | 2021-09-23 |
| EP3879069B1 (en) | 2022-03-23 |
| CN111155972B (en) | 2020-09-22 |
| DK3879069T3 (en) | 2022-04-04 |
| JP2021139274A (en) | 2021-09-16 |
| CN111155972A (en) | 2020-05-15 |
| JP6892177B1 (en) | 2021-06-23 |
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