CN104265250A - Rapid induced flow completion pipe column for subsurface nitrogen making gas well - Google Patents
Rapid induced flow completion pipe column for subsurface nitrogen making gas well Download PDFInfo
- Publication number
- CN104265250A CN104265250A CN201410474396.3A CN201410474396A CN104265250A CN 104265250 A CN104265250 A CN 104265250A CN 201410474396 A CN201410474396 A CN 201410474396A CN 104265250 A CN104265250 A CN 104265250A
- Authority
- CN
- China
- Prior art keywords
- induced flow
- gas well
- oil
- oil pipe
- hole
- 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.)
- Pending
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 30
- 239000007789 gas Substances 0.000 title abstract description 23
- 238000007789 sealing Methods 0.000 claims abstract description 34
- 238000003780 insertion Methods 0.000 claims abstract description 14
- 230000037431 insertion Effects 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 10
- 239000003129 oil well Substances 0.000 claims abstract description 10
- 239000004576 sand Substances 0.000 claims abstract description 8
- 239000003999 initiator Substances 0.000 claims description 17
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 11
- 238000010304 firing Methods 0.000 claims description 9
- 210000002445 nipple Anatomy 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 6
- 238000012360 testing method Methods 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 8
- 241000191291 Abies alba Species 0.000 description 2
- 238000005474 detonation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000008398 formation water Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000003380 propellant Substances 0.000 description 1
- 230000035939 shock Effects 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
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
-
- 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
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
Landscapes
- 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)
- Pipe Accessories (AREA)
Abstract
The invention discloses a rapid induced flow completion pipe column for a subsurface nitrogen making gas well. The rapid induced flow completion pipe column for the subsurface nitrogen making gas well is mainly formed by a mandrel hanger, an oil tube, a subsurface safety valve, a production packer, a working barrel, an insertion positioning seal, a blind tube and a subsurface nitrogen induced flow device; the upper end of the oil tube hangs inside an oil well through the mandrel hanger; the subsurface safety valve, the production packer and the working barrel are respectively arranged on the oil tube; the lower end of the oil tube is connected with the blind tube through the insertion positioning seal; the insertion positioning seal is inserted inside a sealing cylinder of a sand control packer inside the oil well; the subsurface nitrogen making induced flow device is inserted to the blind tube; the subsurface nitrogen making induced flow device is mainly formed by an ignition head, an exploder, a booster tube, a detonating cord, a gas generating agent and an outer casing; the ignition head is arranged at the top of the exploder; the exploder is connected with the detonating cord through the booster tube; the outer casing is full of the gas generating agent which is connected with the detonating cord. According to the above structural form, the rapid induced flow completion pipe column for the subsurface nitrogen making gas well has the advantages of being few in induced flow operation equipment, simple in operation process, high in efficiency, low in cost and stable and reliable.
Description
Technical field
The present invention relates to a kind of induced flow completion tubular column, specifically the quick induced flow completion tubular column of nitrogen gas well is made in a kind of down-hole.
Background technology
At present, offshore gas well first enters completion tubular column down usually, then carries out induced flow separately, and completion tubular column itself does not possess the function of induced flow.Offshore gas well induced flow adopts coiled tubing nitrogen injection induced flow technology usually.This technology needs to connect on offshore boring island to make nitrogen (liquid nitrogen) equipment and continuous oil pipe device, and implement is many, operation procedure is complicated, the activity duration is long, operating cost is high, there is larger risk simultaneously.In addition, narrow tube nitrogen induced flow technology and multistage gas lift tubing string induced flow technology is still had.Narrow tube nitrogen induced flow technology pluses and minuses are identical with coiled tubing nitrogen injection induced flow technology.Multistage gas lift tubing string induced flow technology is limited by the tightness problem of gas lift valve in long-term production process, and flexibility is simultaneously poor, and application is less at present.
The common problem that current gas well completion tubing string exists is that tubing string itself does not possess induced flow function, needs independent induced flow, and induced flow implement is many, operation procedure is complicated, efficiency is low, cost is high, risk is larger.
There is no the quick induced flow completion tubular column of gas well at present, is below the Patents retrieved.
It is CN201159066Y that State Intellectual Property Office discloses publication number on December 3rd, 2008, and patent name is the patent document of high-pressure oil-gas well test induced flow valve, is applicable to the negative pressure test jobs of various high-pressure oil-gas well.This patent comprises sealing test valve and spool fishery, and the body of fishing for of spool fishery is connected with the valve body of sealing test valve.Use this patent effectively can carry out induced flow to high-pressure oil-gas well, improve the test success rate of Oil/gas Well and can increase work efficiency.Construction is in time, easy to operate, only need by this patent with test string down in well, utilize cementing truck to suppress the operation that can complete and open this induced flow valve, reach the object of induced flow.
It is CN2351548Y that State Intellectual Property Office discloses publication number on December 1st, 1999, patent name is the patent document that nitrogen induced flow device is made in a kind of down-hole, this patent belongs to the downhole tool that oilfield uses, it comprises main body, packing, shear pin, inner sleeve, pipe nipple, overcoat, spring, lower contact composition, this patent is owing to have employed the structure of main body, inner sleeve, spring, it can produce enough negative pressure value near shaft bottom, by utilizing the energy induced flow oil well of well dynamic, improve oil production, reduce oil extraction in oil field cost, improve oilfield economic benefit.Its structure is simple, technique is simple, success rate is high.
It is CN102733787A that State Intellectual Property Office discloses publication number on October 17th, 2012, patent name is the Patent Application Publication of plug-in type coiled tubing induced flow device, present patent application document comprises outer tubing string, coiled tubing, coiled tubing injector, described coiled tubing is sent in outer tubing string by coiled tubing injector, be provided with in described outer tubing string and insert location sealing blind pipe, the described periphery of insertion location sealing blind pipe and the inner circumferential of outer tubing string are sealed and matched, the lower end of described coiled tubing is provided with insertion seal bar, insert seal bar and be provided with the through hole be communicated with coiled tubing vertically, when coiled tubing is sent into precalculated position in outer tubing string downwards by described coiled tubing injector, described insertion seal bar is inserted in sealing blind pipe, the periphery of inserting seal bar is sealed and matched with the inner circumferential inserting location sealing blind pipe.Formation water output when present patent application document can solve oil and gas well testing, major diameter tubing string takes the undesirable problem of liquid effect, also can carry out conventional gaslift induced flow, ask and produce and test, reach the object of one-trip string several functions.
Above-mentioned patent or Patent Application Publication different from the technical scheme of this patent.
Summary of the invention
The object of the invention is to overcome deficiency of the prior art, provide the down-hole that a kind of induced flow implement is few, operation procedure is simple, efficiency is high, cost is low, reliable and stable to make the quick induced flow completion tubular column of nitrogen gas well.
For achieving the above object, the technical solution adopted in the present invention is:
The quick induced flow completion tubular column of nitrogen gas well is made in down-hole, it makes nitrogen induced flow device composition primarily of tubing hanger, oil pipe, storm valve, production packer, insertion location sealing, blind pipe and down-hole, wherein, the upper end of described oil pipe is hung in oil well by tubing hanger, storm valve, production packer and seating nipple are located on oil pipe respectively, the lower end of oil pipe is connected with blind pipe by inserting location sealing, described insertion location sealing is inserted in the sealing drum of the sand control packer in oil well, and down-hole is made nitrogen induced flow device and is located in blind pipe.
Described down-hole is made nitrogen induced flow device and is formed primarily of igniter head, initiator, detonating primer, detonating fuse, gas-forming agent and shell, described igniter head is located at the top of initiator, initiator is connected with detonating fuse by detonating primer, and gas-forming agent is loaded in the enclosure, is connected with detonating fuse.
Described igniter head adopts firing pin type igniter head, also comprises fire rod, described fire rod, in order to drop into from the upper port of oil pipe in oil pipe and to fall along oil pipe, fire rod clashes into firing pin type igniter head, and the striker impact initiator of firing pin type igniter head, initiator is detonated.
Sealing ring is provided with between described insertion location sealing and the sealing drum of sand control packer; Described sealing ring is provided with two.
Beneficial effect of the present invention: owing to adopting above-mentioned form of structure, this patent has that induced flow implement is few, operation procedure is simple, efficiency is high, cost is low, stable can be steady feature.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:
Fig. 1 is structural representation of the present invention;
Fig. 2 is for making the structural representation of nitrogen induced flow device in down-hole shown in Fig. 1.
In figure: 1, tubing hanger; 2, oil pipe; 3, storm valve; 4, sealing ring; 5, production packer; 6, location sealing is inserted; 7, blind pipe; 8, nitrogen induced flow device is made in down-hole; 9, oil well; 10, igniter head; 11, initiator; 12, detonating primer; 13, detonating fuse; 14, gas-forming agent; 15, shell; 16, fire rod; 17, sand control packer;
18, seating nipple.
Detailed description of the invention
As shown in Figure 1, 2, the quick induced flow completion tubular column of nitrogen gas well is made in down-hole, and it makes nitrogen induced flow device 8 and primarily of tubing hanger 1, oil pipe 2, storm valve 3, production packer 5, insertion location sealing 6, blind pipe 7, down-hole
seating nipple 18composition, wherein, the upper end of described oil pipe 2 is hung in oil well 9 by tubing hanger 1, storm valve 3 and production packer 5 are located on oil pipe 2 respectively, the lower end of oil pipe 2 is connected with blind pipe 7 by inserting location sealing 6, described insertion location sealing 6 is inserted in the sealing drum of the sand control packer 17 in oil well 9, and down-hole is made nitrogen induced flow device 8 and is located in blind pipe 7.Sealing ring 4 is provided with between described insertion location sealing 6 and the sealing drum of sand control packer 17; Described sealing ring 4 is provided with two.
Described down-hole is made nitrogen induced flow device 8 and is formed primarily of igniter head 10, initiator 11, detonating primer 12, detonating fuse 13, gas-forming agent 14 and shell 15, described igniter head 10 is located at the top of initiator 11, initiator 11 is connected with detonating fuse 13 by detonating primer 12, gas-forming agent 14 is filled in shell 15, is connected with detonating fuse 13.
Described igniter head 10 adopts firing pin type igniter head, also comprises fire rod 16, described fire rod 16, in order to drop into from the upper port of oil pipe in oil pipe and to fall along oil pipe, fire rod clashes into firing pin type igniter head, and the striker impact initiator of firing pin type igniter head, initiator 11 is detonated.
Operating principle: make the quick induced flow completion tubular column of nitrogen gas well under certain gas well lower going-into-well, completion practice installs christmas tree, set test envelope production packer qualified after, open all valves making nitrogen induced flow device from christmas tree cap to down-hole, drop into fire rod from gas production treetop.Fire rod is made nitrogen induced flow device inner chamber accelerates shock excitation well make nitrogen induced flow device from tubing hanger, oil pipe, storm valve, pressure bomb, production packer, seating nipple, location sealing, down-hole, point of release duration and degree of heating striker, excites initiator to produce detonation.Detonation is delivered to gas-forming agent by detonating primer, detonating fuse, and excited gas propellant produces rapidly a large amount of nitrogen, and gas well is lured work, thus produces a large amount of nitrogen and realize gas well induced flow.
The above is the preferred embodiment of the present invention; certainly the interest field of the present invention can not be limited with this; should be understood that; for those skilled in the art; technical scheme of the present invention is modified or equivalent replacement, do not depart from the protection domain of technical solution of the present invention.
Claims (5)
1. the quick induced flow completion tubular column of nitrogen gas well is made in a down-hole, it is characterized in that: it is primarily of tubing hanger, oil pipe, storm valve, production packer, seating nipple, insert location sealing, nitrogen induced flow device composition is made in blind pipe and down-hole, wherein, the upper end of described oil pipe is hung in oil well by tubing hanger, storm valve, production packer and seating nipple are located on oil pipe respectively, the lower end of oil pipe is connected with blind pipe by inserting location sealing, described insertion location sealing is inserted in the sealing drum of the sand control packer in oil well, down-hole is made nitrogen induced flow device and is located in blind pipe.
2. the quick induced flow completion tubular column of nitrogen gas well is made in down-hole according to claim 1, it is characterized in that: described down-hole is made nitrogen induced flow device and formed primarily of igniter head, initiator, detonating primer, detonating fuse, gas-forming agent and shell, described igniter head is located at the top of initiator, initiator is connected with detonating fuse by detonating primer, gas-forming agent is loaded in the enclosure, is connected with detonating fuse.
3. the quick induced flow completion tubular column of nitrogen gas well is made in down-hole according to claim 2, it is characterized in that: described igniter head adopts firing pin type igniter head, also comprise fire rod, described fire rod, in order to drop into from the upper port of oil pipe in oil pipe and to fall along oil pipe, fire rod clashes into firing pin type igniter head, and the striker impact initiator of firing pin type igniter head, initiator is detonated.
4. the quick induced flow completion tubular column of nitrogen gas well is made in down-hole according to claim 3, it is characterized in that: be provided with sealing ring between described insertion location sealing and the sealing drum of sand control packer.
5. the quick induced flow completion tubular column of nitrogen gas well is made in down-hole according to claim 4, it is characterized in that: described sealing ring is provided with two.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410474396.3A CN104265250A (en) | 2014-09-17 | 2014-09-17 | Rapid induced flow completion pipe column for subsurface nitrogen making gas well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410474396.3A CN104265250A (en) | 2014-09-17 | 2014-09-17 | Rapid induced flow completion pipe column for subsurface nitrogen making gas well |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104265250A true CN104265250A (en) | 2015-01-07 |
Family
ID=52156808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410474396.3A Pending CN104265250A (en) | 2014-09-17 | 2014-09-17 | Rapid induced flow completion pipe column for subsurface nitrogen making gas well |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104265250A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106930715A (en) * | 2017-05-15 | 2017-07-07 | 中国石油化工股份有限公司 | Oil-water well self-propelled nitrogen negative pressure returns row casting and dragging free device and its application method |
| CN108086946A (en) * | 2018-01-18 | 2018-05-29 | 江苏航天鸿鹏数控机械有限公司 | Gas well induced flow switch valve |
| CN110761748A (en) * | 2018-04-02 | 2020-02-07 | 刘玉友 | Ball-throwing type pump-free exploitation device for oil field |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4410041A (en) * | 1980-03-05 | 1983-10-18 | Shell Oil Company | Process for gas-lifting liquid from a well by injecting liquid into the well |
| RU2059071C1 (en) * | 1994-02-08 | 1996-04-27 | Сергей Николаевич Пастух | Method for producing high-temperature supersonic jet |
| CN201386541Y (en) * | 2009-04-09 | 2010-01-20 | 刘晓棠 | Wax removal and well cleanout device for gas heat carrier |
| CN201386550Y (en) * | 2009-04-09 | 2010-01-20 | 刘晓棠 | Mixed gas injection device for heavy oil combustion |
| CN202194623U (en) * | 2011-08-29 | 2012-04-18 | 中国石油集团川庆钻探工程有限公司 | Combination structure of a compound oil pipe well completion pipe string |
| CN102562023A (en) * | 2012-03-06 | 2012-07-11 | 中国矿业大学 | System for improving air permeability of coal by using warm-pressing inert gas |
| CN102733787A (en) * | 2012-07-12 | 2012-10-17 | 中国海洋石油总公司 | Plug-in coiled tubing induced-spraying device |
| CN103982168A (en) * | 2014-04-21 | 2014-08-13 | 中北大学 | Underground multi-stage intelligent high pressure gas pulse formation fracturing device and method thereof |
| CN204140035U (en) * | 2014-09-17 | 2015-02-04 | 中国海洋石油总公司 | The quick induced flow completion tubular column of nitrogen gas well is made in down-hole |
-
2014
- 2014-09-17 CN CN201410474396.3A patent/CN104265250A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4410041A (en) * | 1980-03-05 | 1983-10-18 | Shell Oil Company | Process for gas-lifting liquid from a well by injecting liquid into the well |
| RU2059071C1 (en) * | 1994-02-08 | 1996-04-27 | Сергей Николаевич Пастух | Method for producing high-temperature supersonic jet |
| CN201386541Y (en) * | 2009-04-09 | 2010-01-20 | 刘晓棠 | Wax removal and well cleanout device for gas heat carrier |
| CN201386550Y (en) * | 2009-04-09 | 2010-01-20 | 刘晓棠 | Mixed gas injection device for heavy oil combustion |
| CN202194623U (en) * | 2011-08-29 | 2012-04-18 | 中国石油集团川庆钻探工程有限公司 | Combination structure of a compound oil pipe well completion pipe string |
| CN102562023A (en) * | 2012-03-06 | 2012-07-11 | 中国矿业大学 | System for improving air permeability of coal by using warm-pressing inert gas |
| CN102733787A (en) * | 2012-07-12 | 2012-10-17 | 中国海洋石油总公司 | Plug-in coiled tubing induced-spraying device |
| CN103982168A (en) * | 2014-04-21 | 2014-08-13 | 中北大学 | Underground multi-stage intelligent high pressure gas pulse formation fracturing device and method thereof |
| CN204140035U (en) * | 2014-09-17 | 2015-02-04 | 中国海洋石油总公司 | The quick induced flow completion tubular column of nitrogen gas well is made in down-hole |
Non-Patent Citations (1)
| Title |
|---|
| 袁秋长: "排液燃气发生器的设计及参数计算", 《火***学报》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106930715A (en) * | 2017-05-15 | 2017-07-07 | 中国石油化工股份有限公司 | Oil-water well self-propelled nitrogen negative pressure returns row casting and dragging free device and its application method |
| CN108086946A (en) * | 2018-01-18 | 2018-05-29 | 江苏航天鸿鹏数控机械有限公司 | Gas well induced flow switch valve |
| CN108086946B (en) * | 2018-01-18 | 2024-02-20 | 江苏航天鸿鹏数控机械有限公司 | Gas well blowout inducing switch valve |
| CN110761748A (en) * | 2018-04-02 | 2020-02-07 | 刘玉友 | Ball-throwing type pump-free exploitation device for oil field |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104278978B (en) | Soluble bridge plug fracturing technology pipe string and fracturing method thereof | |
| US20110132608A1 (en) | Device for the Focus and Control of Dynamic Underbalance or Dynamic Overbalance in a Wellbore | |
| CN103352684B (en) | Chemical Physics compound explosion fracturing equipment and manufacture method thereof | |
| CN103410484B (en) | A kind of minor diameter tubing pump is crossed pump school and is deeply penetrated and adopt connection and make production method | |
| CN201531261U (en) | Deflagration fracturing device used in cased well | |
| CN104373093A (en) | Underground nitrogen-making induced flow completion pipe string having pressure monitoring function | |
| CN109025915B (en) | Full-drift-diameter cross-isolation lower-return-hole-testing combined pipe column and operation method thereof | |
| WO2006045248A1 (en) | A high-energy gas fracture tool for through-tubing operation | |
| CN109083625A (en) | A kind of full-bore is across every combined operation of perforation and testing tubing string and its operating method | |
| CN107654213B (en) | High-energy negative pressure blocking remover | |
| CN206581900U (en) | A kind of multistage ignites the safe tubing string of explosion fracturing step by step | |
| CN104265250A (en) | Rapid induced flow completion pipe column for subsurface nitrogen making gas well | |
| CN202300348U (en) | Ball-off type pressure tapping detonating device | |
| CN201531256U (en) | Dynamic seal press device for improving fracturing effect of composite perforation | |
| US9470079B1 (en) | High energy gas fracturing device | |
| CN102052066A (en) | Dynamic seal pressing method and device for improving complex perforation pressing crack effect | |
| CN106593387B (en) | A method of realizing the more cluster pressure breaks of horizontal well in segments | |
| CN108222911B (en) | Horizontal open hole well production increasing completion pipe string and combined operation method | |
| CN108915661B (en) | Deflagration fracturing downhole experiment method for open hole well | |
| WO2020139459A2 (en) | Expanding sleeve for isolation | |
| CN107130945A (en) | A kind of rupture disk perforated casing box cupling device | |
| CN105089581B (en) | A kind of Large Diameter Pipeline gas well well flow rate controller and process | |
| CN104265251A (en) | Nitrogen making induced flow device | |
| CN204140036U (en) | Make nitrogen induced flow device | |
| CN204140035U (en) | The quick induced flow completion tubular column of nitrogen gas well is made in down-hole |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20150107 |
|
| RJ01 | Rejection of invention patent application after publication |