某高压气井13Cr油管柱泄漏和腐蚀原因分析

某高压气井完井后,13Cr不锈钢特殊螺纹接头油管柱泄漏,套管压力升高,不得不进行修井作业。对该井取出的油管现场端和工厂端螺纹接头逐根检测,发现多根油管腐蚀和泄漏。抽样分析表明,油管力学性能符合工厂规定;该种13Cr油管材料在该井工况条件下不抗腐蚀,油管接头结构导致腐蚀集中,在油井酸化后接头已发生腐蚀,导致接触压力不足,油管接头部位比管体内壁腐蚀更为严重。     

某油井用13Cr油管腐蚀原因分析

近年来,国内油田发生多起13Cr油管腐蚀失效事故,腐蚀部位主要集中在油管接头,腐蚀基本特征均为点蚀.某油井于2004年4月下入一批特殊扣13Cr油管,2010年6月对该井进行修井作业时,取出油管后发现大量油管的外螺纹接头台肩内壁及倒角消失部位存在明显腐蚀坑,油管下井深度为5001.85 m.本文以该井为例,通过理化检验及微观分析等手段对13Cr     

特殊螺纹接头油管腐蚀原因分析

对某井特殊螺纹接头油管腐蚀穿孔事故进行了调查研究,对腐蚀穿孔的油管接头样品的化学成分、力学性能、金相组织进行了试验分析,对油管腐蚀形貌进行了微观分析和宏观分析,对油管腐蚀产物进行了能谱分析,依据试验结果对袖管腐蚀的原因进行了分析讨论．认为油管属于局部冲刷腐蚀,冲刷腐蚀原因是接头部位存在结构变化引起的紊流。     

API油管腐蚀失效原因分析

    对API（美国石油学会）油管腐蚀失效事故进行了系统调查,结果表明,API油管接头腐蚀严重区域集中在油管接头现场上扣端外螺纹接头内壁位置,油管腐蚀既与流体冲刷有关.也与CO₂腐蚀有关.经过试验研究,认为API油管接头中部的凹槽位置产生了紊流和剪切应力,腐蚀最严重的区域紊流和剪切应力最严重.为解决结构突变导致的腐蚀集中问题,建议油田使用接头内壁平齐的特殊螺纹接头油管.     

高Cl–环空保护液中超级13Cr油管点腐蚀行为研究

目的 研究超级13Cr管材在油气井服役环境中的点腐蚀失效机制,分析超级13Cr马氏体不锈钢在高温、高Cl⁻环空保护液、超临界H2S/CO2环境中的点腐蚀失效行为,明确其适用性,并提出相应的腐蚀控制措施。方法 通过分析失效油管的宏观形貌、显微组织、腐蚀形貌及腐蚀产物,判断超级13Cr油管现场失效的原因,结合高温高压反应釜模拟井下腐蚀环境,从平均腐蚀速率、点腐蚀速率等方面揭示超级13Cr油管的点腐蚀失效机理。结果 该超级13Cr材质管柱在受到H2S/CO2污染的环空保护液环境下会发生点腐蚀穿孔失效;通过观察现场失效油管发现,在受到腐蚀性气体污染的高Cl⁻环空保护液环境中,油管外壁发生了明显的局部腐蚀,油管腐蚀由外壁向内壁扩展,发生了严重的点腐蚀穿孔,并具有一定的H2S应力腐蚀开裂(SCC)特征;在环空保护液环境下,失效油管表面有Cr、O、Cl、S离子聚集,腐蚀受到CO2-H2S共同影响;模拟腐蚀实验结果显示,超级13Cr油管在腐蚀性气体污染的海水基环空保护液环境下具有点腐蚀敏感性,蚀坑深度为80.346 μm,点腐蚀速率达到10.34 mm/a。结论 超级13Cr油管在环空保护液中具有优异的抗均匀腐蚀能力,但在受到H2S/CO2污染的高Cl⁻环空保护液环境中具有明显点腐蚀倾向,建议环空保护液用淡水配制,并进行除氧处理。     

表面缺欠对超级13Cr油管在气井酸化过程中的腐蚀行为影响研究

目的研究光滑表面、无缺欠原始表面和带缺欠原始表面13Cr油管试样在气井酸化增产改造过程中的腐蚀行为,明确不同表面状态对超级13Cr油管腐蚀行为及机理的影响。方法采用高温高压腐蚀模拟实验,研究了三种表面状态的超级13Cr油管在气井酸化过程中鲜酸和残酸环境下的腐蚀行为。分别通过宏观观察、扫描电镜、三维共聚焦显微镜分析了试样在鲜酸和残酸中腐蚀后的宏观、微观和三维形貌。结果在鲜酸溶液中,无缺欠原始表面试样和带缺欠原始表面试样腐蚀速率相当,但均明显高于光滑表面试样。在残酸溶液中,缺欠导致超级13Cr油管腐蚀速率显著增大,带缺欠原始表面试样的腐蚀速率是,是无缺欠原始表面试样的2倍,光滑试样的7.3倍。结论超级13Cr油管表面状态对其在气井酸化过程中的平均腐蚀速率和局部腐蚀有显著的影响,内表面缺欠会降低其在酸化过程中的耐蚀性能,且此类缺欠对残酸介质更为敏感。     

高温高压环境Cl~-浓度和CO_2分压对不锈钢油管的影响

我国西部气田部分井深已经达到了8000m,因此在油管的选材方面采用大量的耐蚀材料(如13Cr不锈钢等)。超深井工况条件下主要的腐蚀因素包括氯离子和二氧化碳,因此利用高压釜模拟井下高温高压环境,通过改变上述两种腐蚀因素的含量,探究这两种腐蚀因素对13Cr和15Cr不锈钢油管的腐蚀影响。结果表明不锈钢油管点蚀深度随腐蚀介质含量升高而加深,目前的工况条件下不锈钢油管可以满足设计年限。     

天津钢管集团股份有限公司研制的TP-JC锯齿型特殊螺纹油管成功应用于气井

<正>2010年8月,由天津钢管集团股份有限公司研制的Φ88.9mm×6.45mm TP110S TP-JC锯齿型特殊螺纹油管在中石化塔河油田顺利下井,试压正常;此井井深4741m,共使用了422支油管。这是TP-JC锯齿型特殊螺纹油管首次应用于高     

汉廷特殊螺纹接头油套管的技术特点与应用分析

介绍了汉廷特殊螺纹接头油套管系列产品的概况,在对汉廷典型特殊螺纹接头的技术特点进行系统分析的基础上,提出了关于不同设计类型特殊螺纹接头油套管适用工况的建议。简要介绍了汉廷特殊螺纹接头在中石化西南油气分公司的应用情况。     

西部某油田修复油管螺纹处断裂的原因

采用化学成分分析、力学性能分析、金相检查、扫描电子显微镜观察等手段对西部某油田修复油管螺纹处断裂失效进行了分析。结果表明：井下修复油管管体螺纹发生断裂的主要原因是垢下腐蚀与氯化物应力腐蚀开裂;螺纹牙底外表面附着黑色物质引发垢下腐蚀,Cl^-通过缝隙进入金属基体,在拉应力作用下,发生氯化物应力腐蚀开裂,最终造成油管在螺纹处发生断裂。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.