CN213869829U - Device for inhibiting generation of hydrate in shaft by circulating seawater - Google Patents
Device for inhibiting generation of hydrate in shaft by circulating seawater Download PDFInfo
- Publication number
- CN213869829U CN213869829U CN202023092426.4U CN202023092426U CN213869829U CN 213869829 U CN213869829 U CN 213869829U CN 202023092426 U CN202023092426 U CN 202023092426U CN 213869829 U CN213869829 U CN 213869829U
- Authority
- CN
- China
- Prior art keywords
- wall
- riser
- marine riser
- window
- seawater
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
A device for inhibiting generation of well bore hydrates by circulating seawater belongs to the technical field of exploitation of sea natural gas hydrates and comprises an outer sleeve, a marine riser, an oil pipe, a water pump, a pulley, a cable and a motor, wherein the outer sleeve is sleeved outside the marine riser, the marine riser is of a hollow double-layer structure consisting of the outer wall of the marine riser and the inner wall of the marine riser, the outer wall of the marine riser is provided with an upper window and a lower window, and when one of the upper window and the lower window is opened, the other window is shielded; an annular space is formed between the oil pipe and the inner wall of the riser; the cable is wound on the pulley and forms a lifting system with the motor by connecting the outer sleeve; and a pump suction inlet of the water pump is positioned in an annular space formed between the inner wall of the riser and the oil pipe. The utility model directly utilizes the natural seawater to heat the pipe wall of the oil pipe, does not need to provide extra heating energy by people, has low energy consumption, is safe and environment-friendly; the upper windows and the lower windows are arranged at different positions of the outer wall of the marine riser, so that the efficient utilization of the seawater energy of the nodes at different times is realized, and the long-term effective operation of the system can be ensured.
Description
Technical Field
The utility model belongs to a sea area natural gas hydrate exploitation technical field specifically relates to a device that circulating seawater restraines pit shaft hydrate and generates.
Background
During the sea natural gas hydrate exploitation process, natural gas generated by reservoir hydrate decomposition and water flow into the bottom of a well together, and the natural gas and the water move in a wellbore in a gas-water two-phase flow state. The temperature and pressure in the shaft are constantly changed along with the depth of the well under the influence of the temperature of seawater, throttling effect, pressure of the wellhead and the like. For a shaft above a mud line in a deep water low-temperature environment, secondary hydrate is easily generated on the inner wall of the shaft, a pipe column is blocked, and pressure building can be formed in severe cases to cause the pipe column to break, so that huge economic loss is caused.
At present, the commonly used methods for preventing the formation of gas hydrate in a gas well shaft mainly comprise a chemical inhibitor injection method and a downhole throttling method. The chemical inhibitor injection method is to inject chemical agents into a shaft from the ground regularly, breaks the continuity of production, and has the defects of high cost, insufficient safety, environmental protection and the like. The downhole throttling technology is to heat gas by means of formation heat energy to prevent hydrate from being generated, but in a low-temperature deep-water marine environment, the heat dissipation speed is high, and a heat source provided by the formation is not enough to inhibit the generation of secondary hydrate in a shaft.
Still other measures, see patent document, CN201910128714.3, disclose an electromagnetic heating device and method for exploiting seabed combustible ice, wherein a certain length of electromagnetic heating device is installed at the inlet end of an electric submersible pump to heat the bottom of the well, which is not suitable for a well bore above a deep cement line. The document number CN201810345979.4 discloses a method for exploiting natural gas hydrate by using a sleeve type heater, the sleeve type heater is placed in an exploitation interval, and for a low-temperature marine environment, the heat dissipation speed of a shaft is high, and the problem of secondary hydrate blockage of the shaft above a deepwater cement line cannot be solved. The publication No. CN201510183801.0 discloses a method for removing hydrate blockage of a gas recovery well shaft, which removes ice blockage by using reaction of an acidic solution and calcium oxide to release heat, but the method cannot be used for preventing secondary hydrate from generating. Document No. CN201110313048.4 discloses a spontaneous heating natural gas hydrate control device, which works by means of formation gas and is not suitable for gas-water co-production wells.
Therefore, an effective prevention method is urgently needed for the problem of secondary hydrate formation of the shaft above the mud line in the process of exploiting the sea natural gas hydrate.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a device that circulating seawater restraines pit shaft hydrate and generates for solve the problem that pit shaft secondary hydrate formed above the sea area natural gas hydrate exploitation process mud line.
In order to achieve the above purpose, the utility model adopts the following technical scheme: an apparatus for circulating seawater to inhibit hydrate formation in a wellbore, comprising: the outer sleeve is sleeved outside the marine riser, the length of the outer sleeve is larger than the distance between the upper opening window and the lower opening window which are arranged on the outer wall of the marine riser, and the outer sleeve can axially move relative to the marine riser and is used for covering the upper opening window or the lower opening window; the marine riser is of a hollow double-layer structure consisting of an outer wall of the marine riser and an inner wall of the marine riser, an annulus is formed between the outer wall of the marine riser and the inner wall of the marine riser, an upper window and a lower window are arranged on the outer wall of the marine riser, wherein the upper window is located at a position 3-10 m below the sea level, the lower window is located at a position 10-100 m below the sea level, when the device for inhibiting the generation of the wellbore hydrate by circulating seawater works, when one of the upper window and the lower window is open, the other one is shielded, and the temperature of the seawater at the position of the open window is higher than 20 ℃; the oil pipe is positioned in the riser, and an annular space is formed between the oil pipe and the inner wall of the riser; the cable is wound on the pulley, one end of the cable is connected with the motor, and the other end of the cable is connected with the outer sleeve; and a pump suction inlet of the water pump is positioned in an annular space formed between the inner wall of the riser and the oil pipe.
As a preferred scheme of the utility model, the length of outer sleeve is greater than the distance 1m ~ 3m between upper-opening window and the lower-opening window.
As a preferred scheme of the utility model, the pump sunction inlet is located in the position of 5m ~ 20m below the sea water level in the annular space formed between the marine riser inner wall and the oil pipe.
Through the above design scheme, the utility model discloses following beneficial effect can be brought: the utility model provides a device for inhibiting the generation of a shaft hydrate by circulating seawater, which directly utilizes natural seawater to heat the pipe wall of an oil pipe, does not need to provide extra heating energy by people, has low energy consumption, and is safe and environment-friendly; the upper windows and the lower windows are arranged at different positions of the outer wall of the marine riser, so that the efficient utilization of the seawater energy of the nodes at different times is realized, and the long-term effective operation of the system can be ensured.
Drawings
The accompanying drawings description herein is provided to provide a further understanding of the invention and constitute a part of the application of the invention, and the exemplary embodiments and descriptions thereof are used for understanding the invention and do not constitute undue limitations of the invention in the drawings:
FIG. 1 is a diagram of the working state of the device for inhibiting the formation of hydrate in a shaft by circulating seawater in spring and summer.
Fig. 2 is a diagram of the working state of the device for inhibiting the formation of the hydrate in the shaft by circulating seawater in autumn and winter.
The respective symbols in the figure are as follows: 1-an outer sleeve; 2-outer wall of riser; 3-inner wall of the riser; 4-windowing on the upper part; 5-windowing down; 6-oil pipe; 7-a water pump; 8-pump suction inlet; 9-a pulley; 10-a cable; 11-motor.
Detailed Description
In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the drawings of the present invention will be combined below to clearly and completely represent the technical solution of the embodiments of the present invention.
As shown in fig. 1 and 2, arrow a indicates the seawater circulation direction, and arrow b indicates the hydrate reservoir.
As shown in fig. 1 and 2, the device for inhibiting the generation of the hydrate in the shaft by circulating seawater comprises an outer sleeve 1, a marine riser, an oil pipe 6, a water pump 7, a pulley 9, a cable 10 and a motor 11.
The outer sleeve 1 is movably sleeved outside the riser, and the length of the outer sleeve 1 is larger than the distance between the upper opening window 4 and the lower opening window 5 which are arranged on the outer wall 2 of the riser. In order to take account of the window closing effect of the windowing and the pipe consumption, the length of the outer sleeve 1 is larger than the distance between the upper windowing 4 and the lower windowing 5 by 1 m-3 m, and the outer sleeve 1 can axially move relative to the marine riser under the drive of the cable 10 and is used for covering the upper windowing 4 or the lower windowing 5.
The riser is a hollow double-layer structure consisting of a riser outer wall 2 and a riser inner wall 3, and an annulus is formed between the riser outer wall 2 and the riser inner wall 3; the marine riser is a heat-insulation marine riser, specifically, heat-insulation coatings are arranged on the inner surface and the outer surface of the outer wall 2 of the marine riser or the outer wall 2 of the marine riser adopts a double-layer concentric pipe wall, and an annular space of the double-layer concentric pipe wall is filled with heat-insulation materials and inert gases or vacuumized, so that the apparent heat conduction coefficient of the outer wall 2 of the marine riser is kept below 0.04W/m DEG C, and heat is prevented from being transferred to low-temperature seawater at the lower part in the seawater circulation process; the heat insulation coating adopts an aerogel coating or a glass fiber coating. The heat insulating material is one of asbestos, diatomite, perlite, aerogel felt, glass fiber, foam concrete and calcium silicate; the inert gas is one of argon, krypton and xenon. An upper windowing part and a lower windowing part are arranged on the outer wall 2 of the marine riser, wherein the upper windowing part 4 is positioned in a high-temperature region of seawater in spring and summer and is positioned 3-10 m below the sea level; the lower window 5 is positioned in a high-temperature area of seawater in autumn and winter and is positioned 10-100 m below the sea level. The specific position of the window is determined by the vertical temperature distribution of the seawater in the mined sea area because the seawater in different sea areas is vertically distributed in four seasons. When the device for inhibiting the generation of the hydrate in the shaft by circulating seawater works, one of the upper open window 4 and the lower open window 5 is opened, and the other one is shielded, so that the hydrate is prevented from being generated on the inner wall of the oil pipe 6, the opened open window is used as an inlet for seawater to enter the whole device, and the temperature of the seawater at the position of the open window is higher than 20 ℃.
The oil pipe 6 is positioned inside the riser, an annular space is formed between the oil pipe 6 and the inner wall 3 of the riser, and a heat insulation coating is arranged on the inner side of the pipe wall of the oil pipe 6 to prevent heat of the oil pipe 6 from dissipating, so that the temperature of the pipe wall of the oil pipe 6 can be approximately equal to the temperature of circulating seawater, and hydrate can be prevented from being generated on the inner wall of the oil pipe 6. The thermal insulation coating can be selected from an aerogel coating or a glass fiber coating.
The mooring rope 10 is wound on the pulley 9, one end of the mooring rope 10 is connected with the motor 11, the other end of the mooring rope 10 is connected with the sleeve 4, the motor 11 rotates and simultaneously drives the mooring rope 10 to run on the pulley 9, and the outer sleeve 1 is lifted and lowered by changing the rotation direction of the motor 11.
And a pump suction inlet 8 of the water pump 7 is positioned in an annular space formed between the inner wall 3 of the marine riser and the oil pipe 6, and in order to ensure the suction effect, the position of the pump suction inlet 8 is positioned at a position 5-20 m below the sea water level in the annular space formed between the inner wall 3 of the marine riser and the oil pipe 6.
The following detailed description of the specific operation process of the device for inhibiting the formation of hydrate in a shaft by circulating seawater in spring and summer is provided with reference to fig. 1, which specifically includes the following implementation steps:
A. in spring and summer, the temperature of the seawater at the position of the upper window 4 is higher than that of the seawater at the position of the lower window 5, the motor 11 is started, and the motor 11 drives the mooring rope 10 to lower the outer sleeve 1 through the pulley 9;
B. when the outer sleeve 1 is lowered to the position for covering the lower windowing 5 and opening the upper windowing 4, the motor 11 is closed;
C. according to the principle of a U-shaped pipe, seawater sequentially flows into an annular space between the outer wall 2 and the inner wall 3 of the riser and an annular space between the inner wall 3 of the riser and the oil pipe 6 through the upper opening window 4, and a pressure balance system is established;
D. starting a water pump 7, and pumping seawater in the annular space between the inner wall 3 of the marine riser and the oil pipe 6 at a displacement of 45L/s to realize seawater circulation in the marine riser;
E. the seawater pumped by the water pump 7 is directly discharged into the sea.
The following detailed description of the specific operation process of the device for inhibiting the formation of the hydrate in the shaft by circulating seawater in autumn and winter is provided with reference to fig. 2, which specifically comprises the following implementation steps:
A. in autumn and winter, the temperature of the seawater at the position of the lower window 5 is higher than that of the seawater at the position of the upper window 4, the motor 11 is started, the motor 11 drives the cable 10 to lift the outer sleeve 1 through the pulley 9;
B. when the outer sleeve 1 is lifted to the position for covering the upper open window 4 and opening the lower open window 5, the motor 11 is closed;
C. according to the principle of a U-shaped pipe, seawater sequentially flows into an annular space between the outer wall 2 and the inner wall 3 of the riser and an annular space between the inner wall 3 of the riser and the oil pipe 6 through the lower opening window 5, and a pressure balance system is established;
D. starting a water pump 7, and pumping seawater in the annular space between the inner wall 3 of the marine riser and the oil pipe 6 at a discharge capacity of 50L/s to realize seawater circulation in the marine riser;
E. the seawater pumped by the water pump 7 is directly discharged into the sea.
A method of circulating seawater to inhibit wellbore hydrate formation, the method comprising the steps of:
(a) when the temperature of the shallow sea water is higher than that of the middle sea water, the motor 11 drives the mooring rope 10 to lower the outer sleeve 1 through the pulley 9, wherein the shallow sea water is the sea water which is 3-10 m below the sea level, and the middle sea water is the sea water which is 10-100 m below the sea level;
(b) when the outer sleeve 1 is lowered to the position for covering the lower windowing 5 and opening the upper windowing 4, the motor 11 is closed;
(c) according to the principle of a U-shaped pipe, shallow high-temperature seawater sequentially flows into an annular space between the outer wall 2 of the marine riser and the inner wall 3 of the marine riser and an annular space between the inner wall 3 of the marine riser and the oil pipe 6 through the upper opening window 4, and a pressure balance system is established;
(d) starting a water pump 7, pumping seawater in an annular space between the inner wall 3 of the riser and the oil pipe 6 at a discharge capacity of 10L/s-60L/s, and realizing seawater circulation in the riser;
(e) the heat-exchanged seawater pumped by the water pump 7 is directly discharged into the sea;
(f) with the alternation of four seasons, when the temperature of the shallow layer seawater is lower than that of the middle layer seawater, the water pump 7 is closed;
(g) turning on the motor 11, the motor 11 drives the cable 10 to lift the outer sleeve 1 up through the pulley 9;
(h) when the outer sleeve 1 is lifted to the position for covering the upper open window 4 and opening the lower open window 5, the motor 11 is closed;
(i) according to the principle of a U-shaped pipe, the middle-layer seawater flows into the riser through the lower opening window 5;
(j) starting a water pump 7, and extracting seawater in an annular space between the inner wall 3 of the riser and the oil pipe 6 to realize seawater circulation in the riser;
further, in order to ensure that the temperature of the oil pipe 6 is always higher than the generation temperature of the natural gas hydrate, the discharge capacity of the pump can be increased to increase the circulation speed of the seawater, and preferably, the discharge capacity of the pump is more than 30L/s.
In conclusion, aiming at the problem of formation of secondary hydrate of the shaft above the mud line in the exploitation process of the natural gas hydrate in the sea area, the utility model provides a device for inhibiting generation of the shaft hydrate by circulating seawater, which directly utilizes the natural seawater to heat the pipe wall of the oil pipe 6, does not need to provide extra heating energy artificially, and has low energy consumption, safety and environmental protection; the upper opening window 4 and the lower opening window 5 are arranged at different positions of the outer wall 2 of the marine riser, so that the efficient utilization of seawater energy at different time nodes is realized, and the long-term effective operation of the system can be ensured.
Claims (3)
1. An apparatus for circulating seawater to inhibit hydrate formation in a wellbore, comprising: the marine riser comprises an outer sleeve (1), a riser, an oil pipe (6), a water pump (7), a pulley (9), a cable (10) and a motor (11), wherein the outer sleeve (1) is sleeved outside the riser, the length of the outer sleeve (1) is greater than the distance between an upper window (4) and a lower window (5) which are arranged on the outer wall (2) of the riser, and the outer sleeve (1) can axially move relative to the riser and is used for covering the upper window (4) or the lower window (5); the marine riser is of a hollow double-layer structure consisting of a marine riser outer wall (2) and a marine riser inner wall (3), an annulus is formed between the marine riser outer wall (2) and the marine riser inner wall (3), an upper window and a lower window are arranged on the marine riser outer wall (2), wherein the upper window (4) is located at a position 3 m-10 m below the sea level, the lower window (5) is located at a position 10 m-100 m below the sea level, when the device for inhibiting the generation of the wellbore hydrate by circulating seawater works, one of the upper window (4) and the lower window (5) is open, the other one is shielded, and the temperature of the seawater at the position of the open window is higher than 20 ℃; the oil pipe (6) is positioned inside the riser, and an annulus is formed between the oil pipe (6) and the inner wall (3) of the riser; the cable (10) is wound on the pulley (9), one end of the cable (10) is connected with the motor (11), and the other end of the cable is connected with the outer sleeve (1); and a pump suction inlet (8) of the water pump (7) is positioned in an annular space formed between the inner wall (3) of the water-resisting pipe and the oil pipe (6).
2. The apparatus for inhibiting hydrate formation in a wellbore using circulating seawater of claim 1, wherein: the length of the outer sleeve (1) is larger than the distance between the upper windowing (4) and the lower windowing (5) by 1-3 m.
3. The apparatus for inhibiting hydrate formation in a wellbore using circulating seawater of claim 1, wherein: the position of the pump suction inlet (8) is located at a position 5-20 m below the sea water level in an annulus formed between the inner wall (3) of the water-resisting pipe and the oil pipe (6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023092426.4U CN213869829U (en) | 2020-12-21 | 2020-12-21 | Device for inhibiting generation of hydrate in shaft by circulating seawater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023092426.4U CN213869829U (en) | 2020-12-21 | 2020-12-21 | Device for inhibiting generation of hydrate in shaft by circulating seawater |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213869829U true CN213869829U (en) | 2021-08-03 |
Family
ID=77069538
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202023092426.4U Expired - Fee Related CN213869829U (en) | 2020-12-21 | 2020-12-21 | Device for inhibiting generation of hydrate in shaft by circulating seawater |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213869829U (en) |
-
2020
- 2020-12-21 CN CN202023092426.4U patent/CN213869829U/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20200011573A1 (en) | Geothermal system operable between heat recovery and heat storage modes | |
| RU2365747C2 (en) | Method for gas production from underground formation (versions) | |
| CN110644963B (en) | Method for exploiting hydrate based on multilateral well | |
| CN204663496U (en) | A kind of canned pair of down-hole electric submersible pump producing tubular column | |
| CN104763333A (en) | Drilling system and method based on subsea pump pressure control | |
| CN111520110B (en) | Supercritical CO of horizontal well2Method and system for developing enhanced geothermal energy by fracturing | |
| CN111173480B (en) | Natural gas hydrate exploitation method | |
| CN112483052B (en) | Device and method for inhibiting generation of shaft hydrate by circulating seawater | |
| CN215444027U (en) | Ultrasonic vibration combined mining structure for natural gas hydrate depressurization mining | |
| CN213869829U (en) | Device for inhibiting generation of hydrate in shaft by circulating seawater | |
| CN201874543U (en) | Underground boosting water injection process pipe string | |
| CN109630076B (en) | Method for exploiting natural gas hydrate by combining radial horizontal well and pressure reduction and heat injection | |
| CN204532070U (en) | A kind of well system based on subsea pump pressure control | |
| CN116263084A (en) | Drilling and production system and method for offshore natural gas hydrate development | |
| CN113622831A (en) | Offshore thermal recovery electric submersible pump injection-production integrated pipe column and operation method | |
| CN111911117B (en) | Combustible ice exploitation pipe column heated by stratum energy and operation method thereof | |
| CN113513298A (en) | Hot dry rock branch well same-well synchronous injection-production method and injection-production device | |
| CN109441400B (en) | Device and method for removing and preventing wax of gas lift oil production well | |
| CN115726742B (en) | Multi-source multi-method combined exploitation system and method for natural gas hydrate, shallow gas and deep gas | |
| CN110230896B (en) | Underground heat extraction device and underground heat extraction method | |
| CN102720475A (en) | Safe and energy-saving immovable-string viscosity-breaking and paraffin-inhibiting system for offshore oilfields | |
| CN113622832A (en) | Offshore thermal recovery external cable electric submersible pump injection-production integrated pipe column and operation method | |
| CN111997577B (en) | Injection-production integrated tubular column structure of heat-insulation canned electric submersible pump and technological method | |
| US11773653B2 (en) | Double-layer coiled tubing double-gradient drilling system | |
| CN107476785A (en) | A kind of closed flow string of the double submersible electric pumps of Oil/gas Well series connection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20210803 Termination date: 20211221 |