CN208934671U - Valve pipe combined type underground throttle for gas well production - Google Patents
Valve pipe combined type underground throttle for gas well production Download PDFInfo
- Publication number
- CN208934671U CN208934671U CN201821430820.4U CN201821430820U CN208934671U CN 208934671 U CN208934671 U CN 208934671U CN 201821430820 U CN201821430820 U CN 201821430820U CN 208934671 U CN208934671 U CN 208934671U
- Authority
- CN
- China
- Prior art keywords
- throttling
- spool
- valve core
- gas well
- valve
- 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.)
- Active
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 37
- 230000001105 regulatory effect Effects 0.000 claims description 26
- 239000007788 liquid Substances 0.000 claims description 21
- 230000013011 mating Effects 0.000 claims description 15
- 238000013461 design Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 11
- 238000004080 punching Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 74
- 238000000605 extraction Methods 0.000 description 9
- 239000002343 natural gas well Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 210000002445 nipple Anatomy 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 241000521257 Hydrops Species 0.000 description 2
- 206010030113 Oedema Diseases 0.000 description 2
- 238000004873 anchoring Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005183 dynamical system Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000033001 locomotion Effects 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 235000020681 well water Nutrition 0.000 description 2
- 239000002349 well water Substances 0.000 description 2
- 238000013475 authorization Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 208000035475 disorder Diseases 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Lift Valve (AREA)
Abstract
The utility model provides a gas well production is with valve pipe combined type downhole choke ware, the outside of the choke ware shell top of this downhole choke ware is equipped with elasticity adjusting nut, the bottom is connected to the gas production oil pipe in the pit, the cavity upper end inside the choke ware shell is equipped with the throttle valve seat, the center of throttle valve seat is installed with the case centralizer, the cavity lower extreme is equipped with the case director; the upper end of the throttling valve seat is connected with the elastic adjusting nut, the lower end of the throttling valve seat is abutted against the upper end of the throttling valve core, the lower end of the throttling valve core is fixed on the valve core guider, a throttling pipe is formed by punching the middle of the valve core guider, the lower end of the throttling pipe is fixed on the throttling valve core, the upper end of the throttling pipe is connected with the valve core centralizer, the valve core centralizer is sleeved with a valve core balance spring, the upper end of the valve core balance spring is fixed on the elastic adjusting nut, and the lower end of the. The utility model can automatically adjust the throttling pressure according to the bottom stratum pressure and prolong the drainage and gas production period; and no throttling effect is realized in the later period of gas well drainage and production.
Description
Technical field
The utility model belongs to gas well liquid loading production gas technology field, and in particular to a kind of gas well liquid loading valve pipe mating type well
Lower flow controller.
Background technique
Underground throttle device is mounted to appropriate location in gas production tubing string, realizes one of reducing pressure by regulating flow in pit shaft by flow nipple
Kind production scheme.Surface throttling engineering is transferred among pit shaft by which, using stratum thermal energy to the low temperature day after throttling
Right gas heating, prevents Hydrate Plugging phenomenon；The safety of gas production gathering system is improved with producing by throttling simultaneously.
Current underground throttle device is single size flow nipple, cannot be automatically adjusted.When drop in formation pressure, due in well
The effect of flow controller, makes gas well prematurely reduce gas production；When gas production is lower than entrained liquid threshold, if being not taken out in time
Flow controller then easily causes hydrops in well that can not carry output ground, causes the water logging of gas well.Meanwhile flow controller salvages work at present
Skill is complicated, and success rate is not high, and construction operation cost is big.
Number of patent application discloses a kind of air tap of underground throttle with eddy current effect for 201120429624.7, in well
Vortex water conservancy diversion version is set in the gas nozzle of lower flow controller, when air-flow passes through, due to the effect of vortex deflector, the multiphase flow of disorder
It is converted into a kind of orderly vortex, gas is upward in the form of continuous air column in oil pipe immediate vicinity, this forms of motion energy
The pressure loss for the movement for keeping gas upward reduces, and increases gas flow rate, and the final fluid-carrying capability for enhancing gas well extends gas well
The aneroid production cycle.The problem of patent solves the problems, such as flow controller hydrops, but flow controller gas nozzle needs repeatedly replacement, still
In the presence of.
Chinese patent literature disclose " a kind of natural gas well underground throttle device " (the patent CN203347761U day for announcing:
2013-12-18), this publication disclose a kind of natural gas well underground throttle device, including central tube, central tube is equipped with and beats
Neck, flow nipple are fished out, is additionally provided with anchoring system, sealing system and dynamical system on central tube, anchoring system includes slips, fixation
Cone and removable pin, the fixed cone is fixed on central tube by removable pin, and fixed cone is inserted into slips.Using above-mentioned knot
Structure can reduce the size of flow controller, to adapt to the lesser oil pipe of diameter, improve the versatility of flow controller.Wherein, patent text
It offers between packing element and sleeve equipped with spring one；Dynamical system includes pusher head and fixed pin, and the pusher head is assemblied in set
It on cylinder, and is connect by fixed pin with central tube, spring two is equipped between the sleeve and central tube.For structure,
When salvaging the above-mentioned natural gas well underground throttle device of replacement, slips smoothly exits fixed cone and unseals under the shock of external force, and packing element
In lower section under the action of spring force, pusher head can not be exited, cannot be unsealed, natural gas well underground throttle device process is above proposed and locates always
In setting state, then plus natural gas well underground throttle device upper end sand grains and dirt with the growth of setting time it is cumulative,
Cause fishing difficult, or even failure.
Chinese patent literature discloses a kind of " 27/8 inch of natural gas well underground throttle device " (Authorization Notice No. CN
201326408Y), including gas nozzle and shell, gas nozzle, that is, gas outlet, shell include lower core bar, bushing, attachment cap, lock tube etc., gas
Mouth is set in the lower stomidium of lower core bar, and it is setting firm that this device realizes flow controller, and resistance to pressure difference is high, unseals reliable legibility
Envelope, flow controller go into the well be hampered steadily above mention it is not setting, anchor mechanism when well operations under flow controller, solution sealing mechanism, sealing mechanism with
Locking mechanism is in relative tension state under the action of rubbing righting mechanism, and it is existing that the anchor mechanism of flow controller will not generate accidentally seat
As the problem of having well solved existing differential flow controller frequent failure.But this mechanical balance type downhole choke device
Every set is only equipped with a throttling gas nozzle, after gas well installs downhole choke device, as gas well mining time extends, gas pressure,
Yield can gradually decrease, and the throttling technological parameter that early period, design matched is caused to be difficult to meet the normal of gas well difference production period
Production requirement, such as gas well are difficult to complete to stop production with production or gas well plug-ging water logging, seriously affect development effectiveness.Therefore, in order to protect
Gas well continuous and stable production is demonstrate,proved, gas well needs to regularly replace various sizes of throttling gas nozzle, at this moment must just salvage downhole choke
Device, the replacement that throttling gas nozzle is completed on ground are launched again again later, due to underground working complexity, the dispensing of downhole choke device
There is a certain security risk with fishing, and frequently dispensing and fishing can additionally increase investment cost.
Utility model content
In order to solve the above problems existing in the present technology, the utility model provides a kind of gas well liquid loading valve pipe combination
Type underground throttle device, purpose according to borehole pressure automatic adjustment choke pressure first is that can realize better water pumping gas production, extend
The gas well liquid loading period；Purpose salvages construction operation second is that the utility model eliminates flow controller, saves gas well heavy repair task expense.
To achieve the goals above, the utility model adopts the following technical solution:
A kind of gas well liquid loading valve pipe mating type underground throttle device, by flow controller shell, spool guider, throttling valve core,
Throttle valve seat, spool balancing spring, elastic force regulating nut, spool centralizer composition, the tip exterior of the flow controller shell are set
It is equipped with elastic force regulating nut, the bottom end of flow controller shell is connected to underground gas production oil pipe, and the inside of flow controller shell is hollow cavity
Body, the hollow cavity upper end are provided with throttle valve seat, and the center of throttle valve seat is equipped with spool centralizer, hollow cavity lower end
It is provided with spool guider；The throttle valve seat upper end is connect with elastic force regulating nut, on throttle valve seat lower end and throttling valve core
End abuts, and throttling valve core lower end is fixed on spool guider, and the intermediate perforation of spool guider forms throttle pipe, the throttling
The lower end of pipe is fixed in throttling valve core, and the upper end of throttle pipe is connected with spool centralizer, is arranged with spool on spool centralizer
The upper end of balancing spring, the spool balancing spring is fixed on elastic force regulating nut, and the lower end of spool balancing spring is fixed on
In throttling valve core.
The throttling valve core top has outer scalene cone, and throttle valve seat bottom end has and scalene cone phase outside throttling valve core top
Matched interior scalene cone, the outer scalene cone are identical as the taper of interior scalene cone.
The throttle pipe is the center hole throttling passage of cross brace shape design.
The elastic force of the spool balancing spring can be adjusted by elastic force regulating nut.
The throttle valve seat and flow controller shell are integrally designed.
The throttling valve core and spool guider are integrally designed.
Pass through screwed connection between the elastic force regulating nut and throttle valve seat.
The upper end of the spool balancing spring and elastic force regulating nut are welded to connect, the lower end of spool balancing spring and throttling
Spool is welded to connect.
The flow controller shell is by screwed connection in underground gas production oil pipe.
A kind of application method of gas well liquid loading valve pipe mating type underground throttle device is gone into operation initial stage in gas well, bottom pressure
It acts in throttling valve core, upper epimerite flow valve core, and the pressure is greater than the elastic force of spool balancing spring, then throttling valve core and throttling
Valve seat combines, and formation gas is only by producing ground after the throttle pipe reducing pressure by regulating flow in throttling valve core；
When strata pressure declines, and gas production reduces, the upper top power that strata pressure suffered by throttling valve core generates reduces, when it
Less than spool balancing spring elastic force when, under the elastic force effect of spool balancing spring, throttling valve core and throttle valve seat are detached from, storage
Layer gas then passes through the extraction ground of the disengaging gap between throttling valve core and throttle valve seat.
The beneficial effects of the utility model are:
1. automatically adjusting choke pressure according to downhole formation pressure, remain compared with high yield tolerance, extends water pumping gas production week
Phase；
2. realizing in the gas well mining later period without throttle effect, flow controller can be saved and salvage construction operation, save gas well overhaul
Operating cost.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of utility model；
Fig. 2 is the partial enlarged view of A-A in Fig. 1.
Description of symbols:
1- flow controller shell, 2- spool guider, 3- throttling valve core, 4- throttle valve seat, 5- spool balancing spring,
6- elastic force regulating nut, 7- throttle pipe, 8- spool centralizer.
Specific embodiment
Embodiment 1
As shown in Figure 1, a kind of gas well liquid loading valve pipe mating type underground throttle device, by flow controller shell 1, spool guider
2, throttling valve core 3, throttle valve seat 4, spool balancing spring 5, elastic force regulating nut 6, spool centralizer 8 form, the flow controller
Elastic regulating nut 6 is arranged in the tip exterior of shell 1, and the bottom end of flow controller shell 1 is connected to underground gas production oil pipe, flow controller
The inside of shell 1 is hollow cavity, and the hollow cavity upper end is provided with throttle valve seat 4, and the center of throttle valve seat 4 is equipped with valve
Core centralizer 8, hollow cavity lower end are provided with spool guider 2；4 upper end of throttle valve seat is connect with elastic force regulating nut 6,
4 lower end of throttle valve seat is abutted with 3 upper end of throttling valve core, and 3 lower end of throttling valve core is fixed on spool guider 2, spool guider 2
Intermediate perforation form throttle pipe 7, the lower end of the throttle pipe 7 is fixed in throttling valve core 3, the upper end of throttle pipe 7 and spool
Centralizer 8 is connected, and spool balancing spring 5 is arranged on spool centralizer 8, bullet is fixed in the upper end of the spool balancing spring 5
On power regulating nut 6, the lower end of spool balancing spring 5 is fixed in throttling valve core 3.
It goes into operation initial stage in gas well, when bottom pressure is higher, gas production is larger, extraction gas only passes through the throttle pipe 7 extraction, real
Now throttling is with production.When strata pressure decline, gas production reduce when, the throttling valve core 3 spool balancing spring effect under with
Throttle valve seat 4 is detached from, and is made to produce gas by the channel extraction between throttle pipe 7 and flow controller shell 1, is preferably realized that taking liquid adopts
Gas extends the gas well water pumping gas production period.
Embodiment 2
On the basis of embodiment 1, the throttling valve core and throttle valve seat contact surface are designed using the conical surface, throttling
3 top of spool has outer scalene cone, and 4 bottom end of throttle valve seat has the interior oblique cone to match with scalene cone outside 3 top of throttling valve core
Face, the outer scalene cone are identical as the taper of interior scalene cone, it can be achieved that combining closely when abutting against.
The throttle valve seat 4 is integrally designed with flow controller shell 1；Throttling valve core 3 and spool guider 2 are integrally designed；Institute
It states and passes through screwed connection between elastic force regulating nut 6 and throttle valve seat 4.
The upper end of the spool balancing spring 5 and elastic force regulating nut 6 are welded to connect, the lower end of spool balancing spring 5 with
Throttling valve core 3 is welded to connect；The elastic force of the spool balancing spring 5 can be adjusted by elastic force regulating nut 6, tune when precession
Greatly, it is turned down when back-out.
Embodiment 3
On the basis of the above embodiments, as shown in Fig. 2, the throttle pipe 7 is the center hole of cross brace shape design
Throttling passage, the diameter of center hole are 3-5mm；When bottom pressure is higher, gas production is larger, extraction gas only passes through the throttling
Pipe extraction realizes throttling with production；When strata pressure declines, and gas production reduces, the throttling valve core 3 is in spool balancing spring
5 effects are lower and throttle valve seat 4 is detached from, and extraction gas is made to pass through the channel between the cross brace shape throttle pipe designed and flow controller shell
Extraction is preferably realized and takes liquid gas production, and the gas well water pumping gas production period is extended.Disengaging between the throttling valve core and throttle valve seat
Gap, in the case where spool balancing spring is acted on from the power between strata pressure, it can be achieved that the automatic continuous adjusting of different choke pressures.
Embodiment 4
A kind of application method of gas well liquid loading valve pipe mating type underground throttle device are as follows:
The flow controller shell 1 is gone into operation initial stage on underground gas production oil pipe in gas well by screwed connection, bottom pressure
It is higher, gas production is larger, bottom pressure acts in throttling valve core 3 at this time, upper epimerite flow valve core 3, and the pressure be greater than spool
The elastic force of balancing spring 5, then throttling valve core 3 is combined with throttle valve seat 4, and formation gas only passes through the throttling in throttling valve core 3
Ground is produced after 7 reducing pressure by regulating flow of pipe；
When strata pressure declines, and gas production reduces, the upper top power that strata pressure suffered by throttling valve core 3 generates reduces, when
When it is less than the elastic force of spool balancing spring 5, under the elastic force effect of spool balancing spring 5, throttling valve core 3 and throttle valve seat 4
It is detached from, reservoir gas then passes through the extraction ground of the disengaging gap between throttling valve core 3 and throttle valve seat 4.Strata pressure is lower, section
Flow valve core 3 and 4 gap of throttle valve seat are bigger (elastic constant of spool balancing spring 5), then throttling action is smaller, up to no section
Stream.
The elastic force of spool balancing spring 5, according to target gas well gas testing yield, can pass through elastic force regulating nut 6 before entering well
Precession tune up, or screw out turn down.When tool enters well, under the elastic force effect of spool balancing spring 5, throttling valve core 3 and throttling
Valve seat 4 completely disengages, and tool is without throttle effect.
Claims (9)
1. a kind of gas well liquid loading valve pipe mating type underground throttle device, it is characterised in that: be oriented to by flow controller shell (1), spool
Device (2), throttling valve core (3), throttle valve seat (4), spool balancing spring (5), elastic force regulating nut (6), spool centralizer (8) group
At elastic regulating nut (6) is arranged in the tip exterior of the flow controller shell (1), and the bottom end of flow controller shell (1) is connected to
The inside of underground gas production oil pipe, flow controller shell (1) is hollow cavity, and the hollow cavity upper end is provided with throttle valve seat (4),
The center of throttle valve seat (4) is equipped with spool centralizer (8), and hollow cavity lower end is provided with spool guider (2)；The throttling
Valve seat (4) upper end is connect with elastic force regulating nut (6), and throttle valve seat (4) lower end is abutted with throttling valve core (3) upper end, throttle valve
Core (3) lower end is fixed on spool guider (2), and the intermediate perforation of spool guider (2) forms throttle pipe (7), the throttling
The lower end of pipe (7) is fixed on throttling valve core (3), and the upper end of throttle pipe (7) is connected with spool centralizer (8), spool centralizer
(8) it being arranged on spool balancing spring (5), the upper end of the spool balancing spring (5) is fixed on elastic force regulating nut (6),
The lower end of spool balancing spring (5) is fixed on throttling valve core (3).
2. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the section
Flow valve core (3) top has outer scalene cone, and throttle valve seat (4) bottom end has to match with scalene cone outside throttling valve core (3) top
Interior scalene cone, the outer scalene cone is identical as the taper of interior scalene cone.
3. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the section
Flow tube (7) is the center hole throttling passage of cross brace shape design.
4. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the valve
The elastic force of core balancing spring (5) can be adjusted by elastic force regulating nut (6).
5. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the section
Valve seat (4) and flow controller shell (1) are flowed to be integrally designed.
6. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the section
Flow valve core (3) and spool guider (2) are integrally designed.
7. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the bullet
Pass through screwed connection between power regulating nut (6) and throttle valve seat (4).
8. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the valve
The upper end and elastic force regulating nut (6) of core balancing spring (5) are welded to connect, the lower end of spool balancing spring (5) and throttling valve core
(3) it is welded to connect.
9. a kind of gas well liquid loading according to claim 1 valve pipe mating type underground throttle device, it is characterised in that: the section
Device shell (1) is flowed by screwed connection in underground gas production oil pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821430820.4U CN208934671U (en) | 2018-09-03 | 2018-09-03 | Valve pipe combined type underground throttle for gas well production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821430820.4U CN208934671U (en) | 2018-09-03 | 2018-09-03 | Valve pipe combined type underground throttle for gas well production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208934671U true CN208934671U (en) | 2019-06-04 |
Family
ID=66719689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821430820.4U Active CN208934671U (en) | 2018-09-03 | 2018-09-03 | Valve pipe combined type underground throttle for gas well production |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208934671U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108894760A (en) * | 2018-09-03 | 2018-11-27 | 中国石油集团川庆钻探工程有限公司 | Valve pipe combined type underground throttle for gas well production and use method thereof |
-
2018
- 2018-09-03 CN CN201821430820.4U patent/CN208934671U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108894760A (en) * | 2018-09-03 | 2018-11-27 | 中国石油集团川庆钻探工程有限公司 | Valve pipe combined type underground throttle for gas well production and use method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108894760A (en) | Valve pipe combined type underground throttle for gas well production and use method thereof | |
| CN201095977Y (en) | Gas lift pipe column for hot washing protective oil layer and no-killing operation | |
| CN103452542B (en) | Switchable fracturing sliding sleeve | |
| CN105443041B (en) | Differential pressure type drill bit | |
| CN107304661A (en) | Single-flow valve assembly, gas lift valve, gas lift tool and integrated tubular column | |
| CN105257256B (en) | Underground gas production tubing string and gas production method | |
| CN105317377A (en) | Center differential pressure type drill bit | |
| CN106837266A (en) | Gas well underground drainage and gas production tool based on integration of jet flow and vortex flow | |
| CN208934671U (en) | Valve pipe combined type underground throttle for gas well production | |
| CN105089581B (en) | Downhole flow control device and process method for large-pipe-diameter gas well | |
| CN202187750U (en) | Preset type underground throttling device | |
| CN106285580B (en) | A kind of underground throttle device | |
| CN206035458U (en) | Clear hole of hydraulic jet pierces through device | |
| CN206299368U (en) | A kind of underground throttle device of easy deblocking | |
| CN202745847U (en) | Controllable hydraulic ejector | |
| CN105201464B (en) | A kind of binodal stem bar underground throttle device | |
| CN201786317U (en) | Super-heavy oil thermal production well oil pipe sealing controller | |
| CN205743858U (en) | Neo-epoxy resin sand screen | |
| CN205618144U (en) | Double -barrelled formula multilayer acidizing water injection string | |
| CN204804767U (en) | Throwing and fishing type high-pressure gas injection valve | |
| CN205225214U (en) | Large-pipe-diameter gas well downhole flow control device | |
| CN202832384U (en) | Single-flow sand-proof blanking plug for water injection well | |
| CN2585975Y (en) | Oil well layered stable and constant steam injection device | |
| CN204357412U (en) | Casing sliding sleeve capable of being repeatedly closed | |
| CN205422659U (en) | Novel reducing sand screen overflows |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20201028 Address after: 100007 Dongcheng District, Dongzhimen, China, North Street, No. 9 Oil Mansion, No. Patentee after: CHINA NATIONAL PETROLEUM Corp. Patentee after: CNPC CHUANQING DRILLING ENGINEERING Co.,Ltd. Address before: No.6, mengzhuiwan street, Chenghua District, Chengdu, Sichuan 610056 Patentee before: CNPC CHUANQING DRILLING ENGINEERING Co.,Ltd. Patentee before: CHINA NATIONAL PETROLEUM CORPORATION CHUANQING DRILLING ENGINEERING COMPANY LIMITED CHANGQING DOWNHOLE TECHNOLOGY Co. |
|
| TR01 | Transfer of patent right |