CN100591803C - 一种抗h2s与co2联合作用下的缓蚀剂 - Google Patents
一种抗h2s与co2联合作用下的缓蚀剂 Download PDFInfo
- Publication number
- CN100591803C CN100591803C CN200610105097A CN200610105097A CN100591803C CN 100591803 C CN100591803 C CN 100591803C CN 200610105097 A CN200610105097 A CN 200610105097A CN 200610105097 A CN200610105097 A CN 200610105097A CN 100591803 C CN100591803 C CN 100591803C
- Authority
- CN
- China
- Prior art keywords
- inhibiter
- quaternary ammonium
- corrosion
- oil
- virahol
- 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
- 230000009471 action Effects 0.000 title claims abstract description 16
- 239000003112 inhibitor Substances 0.000 title abstract description 11
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229940051841 polyoxyethylene ether Drugs 0.000 claims abstract description 30
- 229920000056 polyoxyethylene ether Polymers 0.000 claims abstract description 30
- 125000000217 alkyl group Chemical group 0.000 claims abstract description 4
- -1 methyl quaternary ammonium salt Chemical class 0.000 claims description 42
- 150000003856 quaternary ammonium compounds Chemical class 0.000 claims description 32
- 125000005233 alkylalcohol group Chemical group 0.000 claims description 28
- 229910052717 sulfur Inorganic materials 0.000 claims description 28
- JJDGTGGQXAAVQX-UHFFFAOYSA-N 6-methyl-1-(6-methylheptoxy)heptane Chemical compound CC(C)CCCCCOCCCCCC(C)C JJDGTGGQXAAVQX-UHFFFAOYSA-N 0.000 claims description 20
- 229910019142 PO4 Inorganic materials 0.000 claims description 20
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 20
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 20
- 239000010452 phosphate Substances 0.000 claims description 20
- 150000001412 amines Chemical group 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 125000003118 aryl group Chemical group 0.000 claims description 3
- 125000000753 cycloalkyl group Chemical group 0.000 claims description 3
- 229910052736 halogen Inorganic materials 0.000 claims description 3
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 125000005843 halogen group Chemical group 0.000 claims 1
- 238000005260 corrosion Methods 0.000 abstract description 55
- 230000007797 corrosion Effects 0.000 abstract description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 16
- 238000000034 method Methods 0.000 abstract description 15
- 238000005065 mining Methods 0.000 abstract description 4
- 239000000126 substance Substances 0.000 abstract description 3
- 230000002401 inhibitory effect Effects 0.000 abstract 1
- 239000003921 oil Substances 0.000 description 25
- 238000002360 preparation method Methods 0.000 description 20
- 230000000694 effects Effects 0.000 description 16
- HNNQYHFROJDYHQ-UHFFFAOYSA-N 3-(4-ethylcyclohexyl)propanoic acid 3-(3-ethylcyclopentyl)propanoic acid Chemical compound CCC1CCC(CCC(O)=O)C1.CCC1CCC(CCC(O)=O)CC1 HNNQYHFROJDYHQ-UHFFFAOYSA-N 0.000 description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 14
- 239000007789 gas Substances 0.000 description 13
- 239000003814 drug Substances 0.000 description 12
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 10
- 238000003756 stirring Methods 0.000 description 10
- 230000005764 inhibitory process Effects 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 7
- 229940079593 drug Drugs 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 7
- 230000000116 mitigating effect Effects 0.000 description 7
- 239000003129 oil well Substances 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 230000001954 sterilising effect Effects 0.000 description 5
- 238000004659 sterilization and disinfection Methods 0.000 description 5
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 4
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 230000018044 dehydration Effects 0.000 description 4
- 238000006297 dehydration reaction Methods 0.000 description 4
- 230000003628 erosive effect Effects 0.000 description 4
- 238000009413 insulation Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 238000010792 warming Methods 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000000157 electrochemical-induced impedance spectroscopy Methods 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical group C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 239000010779 crude oil Substances 0.000 description 2
- 230000005518 electrochemistry Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 150000002367 halogens Chemical group 0.000 description 2
- 238000001453 impedance spectrum Methods 0.000 description 2
- 230000010534 mechanism of action Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 229910000926 A-3 tool steel Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 238000000627 alternating current impedance spectroscopy Methods 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 235000009508 confectionery Nutrition 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000000840 electrochemical analysis Methods 0.000 description 1
- 230000001804 emulsifying effect Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 150000002461 imidazolidines Chemical class 0.000 description 1
- 239000012729 immediate-release (IR) formulation Substances 0.000 description 1
- 239000010733 inhibited oil Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000002332 oil field water Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 230000001314 paroxysmal effect Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000007096 poisonous effect Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000000246 remedial effect Effects 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 150000007979 thiazole derivatives Chemical class 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 208000016261 weight loss Diseases 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
- 235000020681 well water Nutrition 0.000 description 1
- 239000002349 well water Substances 0.000 description 1
Images
Landscapes
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
Description
Claims (6)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN200610105097A CN100591803C (zh) | 2006-09-04 | 2006-09-04 | 一种抗h2s与co2联合作用下的缓蚀剂 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN200610105097A CN100591803C (zh) | 2006-09-04 | 2006-09-04 | 一种抗h2s与co2联合作用下的缓蚀剂 |
Publications (2)
Publication Number | Publication Date |
---|---|
CN1966774A CN1966774A (zh) | 2007-05-23 |
CN100591803C true CN100591803C (zh) | 2010-02-24 |
Family
ID=38075744
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN200610105097A Expired - Fee Related CN100591803C (zh) | 2006-09-04 | 2006-09-04 | 一种抗h2s与co2联合作用下的缓蚀剂 |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN100591803C (zh) |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101182410B (zh) * | 2007-11-22 | 2011-02-02 | 张煜 | 一种油田缓蚀剂 |
CN101613598B (zh) * | 2009-07-29 | 2012-02-01 | 中国石油化工集团公司 | 一种抑制h2s/co2腐蚀的缓蚀剂及其制备方法 |
CN101624518B (zh) * | 2009-08-19 | 2012-01-18 | 大庆油田有限责任公司 | 一种适用于co2驱采出井井筒防腐的缓蚀剂 |
CN103059825B (zh) * | 2011-10-18 | 2015-02-18 | 中国石油化工股份有限公司 | 一种油井用缓蚀剂及制备方法 |
CN102627955B (zh) * | 2012-03-29 | 2013-11-13 | 中国石油天然气集团公司 | 连续油管用高温抗o2/co2缓蚀剂及其b剂制备方法 |
CN102732893B (zh) * | 2012-06-25 | 2013-11-06 | 大庆中浮石油技术开发有限公司 | 一种复合缓蚀剂 |
CN102732890B (zh) * | 2012-06-25 | 2013-10-30 | 大庆中浮石油技术开发有限公司 | 含二氧化碳天然气气相缓蚀剂 |
CN102776018A (zh) * | 2012-07-12 | 2012-11-14 | 天津市瑞德赛恩新材料开发有限公司 | 一种延迟焦化多功能缓蚀剂及其制备方法 |
CN103865506B (zh) * | 2014-02-27 | 2017-01-11 | 山东泰和水处理科技股份有限公司 | 一种油气田高温酸化缓蚀剂及其制备方法 |
CN105154048A (zh) * | 2015-07-31 | 2015-12-16 | 西南石油大学 | 一种用于煤层气井井下管杆防co2与o2腐蚀条件的复配缓蚀剂 |
CN106047326B (zh) * | 2016-06-03 | 2019-06-11 | 中国石油天然气股份有限公司 | 一种适用于高矿化度、高钡锶环境的co2驱缓蚀阻垢剂 |
CN107629777B (zh) * | 2017-10-20 | 2020-09-04 | 中国石油大学(北京) | 一种抑制腐蚀的复配型缓蚀剂及其制法与应用 |
CN109652045A (zh) * | 2018-12-12 | 2019-04-19 | 中石化石油工程技术服务有限公司 | 一种用于稠油热采的油井缓蚀剂及其制备方法 |
US11993744B2 (en) | 2022-04-12 | 2024-05-28 | Championx Usa Inc. | Solid paraffin inhibitor and corrosion inhibitor compositions |
CN114990555A (zh) * | 2022-07-05 | 2022-09-02 | 秦皇岛贝特化工科技有限公司 | 一种抗二氧化碳腐蚀的金属缓蚀剂及其制备方法与应用 |
CN115656021A (zh) * | 2022-11-02 | 2023-01-31 | 长庆工程设计有限公司 | 一种油气田站场用腐蚀监控的方法及系统 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1277240A (zh) * | 2000-06-21 | 2000-12-20 | 中国石油天然气总公司石油管材研究所 | 一种油田用新型抗co2腐蚀缓蚀剂 |
CN1410595A (zh) * | 2002-10-24 | 2003-04-16 | 华中科技大学 | 一种抑制碳钢co2腐蚀的水溶性缓蚀剂及其制备方法 |
CN1473962A (zh) * | 2003-06-30 | 2004-02-11 | 中国石油化工集团公司 | 一种缓蚀剂组合物及其制备和应用 |
CN1563494A (zh) * | 2004-03-26 | 2005-01-12 | 沈阳市铭阳防腐研究所 | 抗硫化氢腐蚀缓蚀剂 |
CN1818138A (zh) * | 2005-02-07 | 2006-08-16 | 长江大学 | 一种控制二氧化碳腐蚀的缓蚀剂及其制备方法 |
-
2006
- 2006-09-04 CN CN200610105097A patent/CN100591803C/zh not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1277240A (zh) * | 2000-06-21 | 2000-12-20 | 中国石油天然气总公司石油管材研究所 | 一种油田用新型抗co2腐蚀缓蚀剂 |
CN1410595A (zh) * | 2002-10-24 | 2003-04-16 | 华中科技大学 | 一种抑制碳钢co2腐蚀的水溶性缓蚀剂及其制备方法 |
CN1473962A (zh) * | 2003-06-30 | 2004-02-11 | 中国石油化工集团公司 | 一种缓蚀剂组合物及其制备和应用 |
CN1563494A (zh) * | 2004-03-26 | 2005-01-12 | 沈阳市铭阳防腐研究所 | 抗硫化氢腐蚀缓蚀剂 |
CN1818138A (zh) * | 2005-02-07 | 2006-08-16 | 长江大学 | 一种控制二氧化碳腐蚀的缓蚀剂及其制备方法 |
Also Published As
Publication number | Publication date |
---|---|
CN1966774A (zh) | 2007-05-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN100591803C (zh) | 一种抗h2s与co2联合作用下的缓蚀剂 | |
Olajire | Corrosion inhibition of offshore oil and gas production facilities using organic compound inhibitors-A review | |
CN106479468B (zh) | 一种油气田用有机复合高效除硫剂及其制备方法与应用 | |
Prabha et al. | Corrosion problems in petroleum industry and their solution | |
CN107418549B (zh) | 一种耐温120~140℃的复合酸化缓蚀剂 | |
Benamor et al. | Effect of temperature and fluid speed on the corrosion behavior of carbon steel pipeline in Qatari oilfield produced water | |
Chen et al. | Corrosion behavior study of oil casing steel on alternate injection air and foam liquid in air-foam flooding for enhance oil recovery | |
CN107652965A (zh) | 一种低摩阻胶凝酸及其制备方法 | |
Zhao et al. | Corrosion inhibition approach of oil production systems in offshore oilfields | |
Zeng et al. | Annular corrosion risk analysis of gas injection in CO2 flooding and development of oil-based annulus protection fluid | |
CN105483708A (zh) | 适用于油气田含h2s/co2腐蚀环境输送管线的缓蚀剂及其制备方法 | |
Liu et al. | Novel Ce@ N-CDs as green corrosion inhibitor for metal in acidic environment | |
Dong et al. | Role of polyacrylamide concentration on corrosion behavior of N80 steel in the HPAM/H2S/CO2 environment | |
Ituen et al. | Inhibition of X80 steel corrosion in oilfield acidizing environment using 3-(2-chloro-5, 6-dihydrobenzo [b][1] benzazepin-11-yl)-N, N-dimethylpropan-1-amine and its blends | |
Zhang et al. | Effect of temperature on corrosion behavior of VM110SS casing steel in the CO2/H2S coexistent environment | |
Liu et al. | New corrosion inhibitor for 13Cr stainless steel in 20% HCl solution | |
Sastri | Corrosion processes and the use of corrosion inhibitors in managing corrosion in underground pipelines | |
CN105238379B (zh) | 一种气井酸化用长效缓蚀剂及其配制方法和使用方法 | |
Huttenloch et al. | Inhibitor performance on carbon steel in the geothermal environment of the Upper Rhine graben (Central Europe)–A laboratory study | |
Wang et al. | Corrosion inhibitor development for slight sour environment with oxygen intrusion issue | |
CN102559167A (zh) | 新型希夫碱油井酸化缓蚀剂的制备方法及其应用 | |
CN102585796B (zh) | 酸化缓蚀剂N-(γ-甲基蒽)吡啶氯化物及其制备方法 | |
CN109678800A (zh) | 苄基咪唑啉阳离子化合物、缓蚀剂及制备方法和应用 | |
Li et al. | Experimental study on the corrosion of a downhole string under flue gas injection conditions | |
Huttenloch et al. | Performance of corrosion inhibitors on carbon steel in the geothermal environment of the Upper Rhine Graben (URG) depending on inhibitor concentration, temperature and hydrodynamic conditions—a laboratory study |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C41 | Transfer of patent application or patent right or utility model | ||
TA01 | Transfer of patent application right |
Effective date of registration: 20090109 Address after: Shaanxi province Xi'an Weiyang Weiyang Road No. 151 in Changqing Garden District Changqing headquarters and the Ministry of science and technology project post encoding: 710021 Applicant after: CNPC CHUANQING DRILLING ENGINEERING Co.,Ltd. Address before: Department of science and technology, bureau of Exploration Bureau Changqing District, Shaanxi City, Xi'an Province, China: 710021 Applicant before: Changqing Petroleum Exploration Bureau |
|
ASS | Succession or assignment of patent right |
Owner name: CHINA PETROLEUM GROUP CHUANQING DRILLING ENGINEERI Free format text: FORMER OWNER: CHANGQING PETROLEUM EXPLORATION BUREAU Effective date: 20090109 |
|
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100224 Termination date: 20190904 |
|
CF01 | Termination of patent right due to non-payment of annual fee |