模拟塔里木油田环境中低Cr钢的H_2S/CO_2腐蚀行为

通过高温高压腐蚀试验,运用SEM、XRD、EDS等分析技术.研究了普通P110与3Cr110钢在模拟塔里木油田现场环境中的CO2/H2S腐蚀特征.结果表明:在模拟CO2腐蚀环境中,这两种材料的腐蚀产物为FeCO3,3Cr110表现出良好的抗CO2均匀腐蚀及局部腐蚀能力,其平均腐蚀速率显著小于普通P110;模拟CO2/H2S腐蚀条件下,两种材料的均匀腐蚀速率远小于单独CO2腐蚀环境下的均匀腐蚀速率,表面腐蚀产物为FeS,H2S腐蚀占主导作用,Cr元素在低Cr钢腐蚀产物膜中的富集,其腐蚀产物Cr(OH)3改善了腐蚀产物膜的稳定性,显著提高了低Cr钢的抗均匀腐蚀及局部腐蚀能力.     

90℃时油管钢P110的CO2/H2S腐蚀行为

采用高温高压釜试验,辅以失重法、X射线衍射、扫描电镜和电子能谱分析,对90℃时油管钢P110在模拟油井采出液中的CO2/H2S腐蚀行为进行了研究。结果表明,在本试验条件下,油管钢P110的腐蚀速率高达5.1260mm/a,腐蚀类型以H2S腐蚀(坑蚀)为主,腐蚀产物主要为硫化物。     

高含CO2低含H2S条件下温度对P110碳钢腐蚀规律的影响

为了明确高含CO₂及少量H₂S条件下，温度变化对石油管材P110钢腐蚀速率的影响，利用高温高压硫化氢反应釜开展了腐蚀模拟试验，利用失重法记录腐蚀速率。应用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和激光共聚焦显微镜等，研究并分析了P110钢表面的腐蚀形貌和产物。结果表明：在1 MPa CO₂分压、20 kPa H₂S分压和流速1 m/s条件下，P110钢管材均匀腐蚀速率随温度升高先增大后减小，在100℃附近达到峰值。当温度超过80℃时，P110钢表面腐蚀形态由全面腐蚀转变为局部腐蚀。随着温度的升高，P110钢表面腐蚀产物由富铁结构转变为富硫结构，致密的陨硫铁矿和磁黄铁矿阻碍腐蚀反应的离子扩散。此外，在60～100℃,温度升高会同时促进阴极反应和阳极反应，导致P110钢自腐蚀电流密度增加，腐蚀速率提高，而当温度继续由100℃升高至120℃时，P110钢自腐蚀电流密度减小，腐蚀过程逐渐受到抑制。     

P110SS钢在H2S和CO2环境中的腐蚀特征

利用高温高压哈氏合金反应釜对P110SS油套管钢在不同H2S和CO2环境下的腐蚀行为进行了实验。研究了H2S和CO2分压对P110SS油套管钢腐蚀规律的影响,利用SEM、EDS、XRD等方法分析了腐蚀试样的微观形貌与结构特征,发现P110SS在较低温度条件下,H2S浓度非常低时,腐蚀特征与单纯CO2腐蚀规律相似,腐蚀速率比较高。在相同的H2S分压条件下,随CO2浓度增加,腐蚀速率依次增加。通过应力腐蚀开裂试验表明,P110SS在高温205℃条件下应力腐蚀开裂敏感较小。     

高温高压H2S/CO2腐蚀产物膜对低铬钢氢渗透行为的影响

目的探讨含Cr腐蚀产物膜对油管钢氢渗透行为的影响。方法对80SS、P110-3Cr和P110-7Cr油管钢试样进行高温高压H_2S/CO_2腐蚀模拟实验,并利用双电解池技术测量试样腐蚀前、后的氢渗透电流密度。通过扫描电子显微镜、能谱分析仪和X射线衍射仪对腐蚀产物膜的微观形貌、成分和物相组成进行分析。结果三种材料的腐蚀产物主要由亚稳态的马基诺矿型硫铁化合物构成,没有发现典型的CO_2腐蚀产物FeCO_3晶体,在P110-3Cr(7.4%Cr)和P110-7Cr(14.75%Cr)钢的腐蚀产物膜中有Cr元素富集。随着钢中Cr含量的提高,120℃腐蚀后,试样的表观扩散系数减小。80SS、P110-3Cr和P110-7Cr油管钢试样表面无腐蚀膜时,吸附氢浓度分别为0.98×10~(-5)、9.54×10~(-5)、9.3×10~(-5) mol/cm~3。120℃腐蚀后,带有腐蚀膜试样的膜层/基体界面钢基体侧的吸附氢浓度分别为0.93×10~(-5)、5.17×10~(-5)、8.52×10~(-5) mol/cm~3。结论三种油管钢的腐蚀过程均由H_2S控制。腐蚀产物膜中Cr元素富集有助于降低带有腐蚀膜试样的表观扩散系数。与不带腐蚀膜的试样相比,三种带腐蚀膜试样的膜层/基体界面钢基体侧的吸附氢浓度降低,腐蚀产物膜对氢渗透具有明显的阻碍作用。     

模拟油田H_2S/CO_2环境中油管钢的动态腐蚀行为研究

在模拟油田CO2/H2S共存的腐蚀环境中,研究了温度、CO2分压、H2S分压对N80、P110两种油管钢动态腐蚀行为的影响。结果表明,在实验参数范围内,随着温度、CO2分压、H2S分压的变化,两种材质的动态腐蚀速率都呈现了先增大后减小的变化趋势,且P110钢的腐蚀速率大于N80钢的腐蚀速率。     

CO2对H2S／CO2环境中P110钢应力腐蚀的影响研究

采用恒载荷拉伸法、腐蚀电化学测试和断口分析技术等,研究了P110钢在不同H2S／CO2含量的NACE-A溶液中的硫化物应力腐蚀（SSCC）行为．结果表明,在加载初期,P110钢的自腐蚀电位Ecorr）急剧下降,至极小值后缓慢升高,达到稳定值后直至断裂,试样断口呈脆性解理状．当通入CO2量达到17％时,P110钢的自腐蚀...     

抗硫套管钢P110SS在高含H2S/CO2环境中的腐蚀行为和硫化物应力开裂敏感性研究

利用高温高压反应釜模拟普光气田的工况环境,研究抗硫套管钢P110SS在高含H2S/CO2环境中的腐蚀行为和硫化物应力开裂(SSC)敏感性.结果表明,随着温度和H2S/CO2分压的升高,P110SS的腐蚀速率先降低后升高,而在相当于井中部工况的环境中,钢的腐蚀速率最低,腐蚀产物膜明显脱落.在高含H2S/CO2环境中,采用四点弯曲法加载达到P110SS屈服强度的90%时,试样表面未发现裂纹,表明SSC敏感性比较低.     

高Cl~-条件下H_2S分压对P110钢腐蚀速率的影响

利用高温高压釜设备模拟油气田环境并辅以失重法,研究了高Cl-条件下H2S分压对P110钢腐蚀速率的影响,结果表明:P110钢的腐蚀速率随着H2S分压的增大呈先增大后减小的趋势,且在0.06 MPa时取得最大值;采用扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线能谱仪(EDS)技术对腐蚀产物膜进行分析知:H2S分压通过影响腐蚀产物膜厚度、微观吸附形貌和表面膜成分等,进而影响了P110钢的腐蚀速率.     

页岩气井井筒腐蚀规律与防护措施

为了明确页岩气井井筒的腐蚀规律,对现场取得数据进行灰色关联分析,确定CO2分压、硫酸盐还原菌含量的关联度大于0.7,为影响腐蚀的主控因素。通过动态腐蚀评价试验测定温度、压力、CO2分压和硫酸盐还原菌含量对N80钢和P110钢腐蚀速率的影响。通过腐蚀失重法开展了缓蚀剂的评价及优选试验,结果表明:缓蚀剂2在加注量为200m/L时,对N80钢和P110钢有较好的缓蚀效果,且此时经济效益最大化。     

模拟油田工况条件低Cr钢抗H2S应力腐蚀开裂行为研究

    运用四点弯曲试验方法,参照NACE 0177-2005标准研究了低Cr钢在模拟塔里木油田工况条件下的抗H₂S应力腐蚀开裂（SSC）行为.结果表明：经720小时试验后,0.5 Cr试样表面未发现宏观及微观裂纹,表现出良好的抗SSC能力,而普通3 Cr、5 Cr试样表面均发现宏观及微观裂纹,没有通过抗SSC性能检测;应从成分设计及适当的热处理等方面着手,获得理想的显微组织,来提高3 Cr、5 Cr钢的抗SSC性能.     

Q125级套管钢高频电阻焊接头耐CO2/H2S腐蚀行为

采用SEM,EBSD和电化学等手段研究了Q125级石油套管钢高频电阻焊接头的耐CO₂/H2S腐蚀行为.结果表明,Q125级套管钢高频电阻焊接头处母材的耐腐蚀性能最好,热影响区次之,而焊缝的耐腐蚀性能最差,导致高频电阻焊接头在CO₂/H₂S腐蚀环境中产生了沟槽腐蚀.试验钢焊缝处的大角晶界比例高于母材和热影响区,从而使焊缝区反应速度常数高于母材和热影响区,这是焊缝区腐蚀速率最高的一个重要原因.通过电化学分析表明,焊缝处的电极反应的极化阻力最小,腐蚀反应易于发生;而母材的电极反应的极化电阻最大,腐蚀反应不易进行,这与腐蚀试验所得结果及极化曲线分析结果一致.     

Corrosion resistance of the anti‐sulfide steel in the CO2/H2S containing solutions

The present work primarily investigates the corrosion characterization of the common P110 steel and the anti‐sulfide P110SS steel in CO₂‐containing solution with or without hydrosulfuric acid (H₂S) at 70 °C. The electrochemical techniques such as potentiodynamic polarization sweep and electrochemical impedance spectroscopy (EIS) were used to disclose the differences of the corrosion mechanisms between both P110 and P110SS steels in CO₂‐containing solution with various additions of H₂S. The EIS data fitted by ZsimpWin software were analyzed and discussed. The experimental results indicated that H₂S could accelerate and also inhibit the corrosion attack according to the changes of corrosive environments.     

Strength characteristics of copper/aluminium alloy friction welded joints

The susceptibility to hydrogen-induced cracking in hydrogen sulphide (H₂S) environment of welded API X80 steel was studied. The flux-cored arc welding process was employed with E71-T1 and E71-T8K6 wires. The welding parameters were kept constant, but the samples were welded using different preheat temperatures (room temperature and 100°C). The gapped bead-on-plate (G-BOP) test was used. The specimens of modified G-BOP tests were exposed to an environment saturated with H₂S, as recommended by the NACE TM0284 standard. The weld beads were characterized by optical microscopy and the level of residual hydrogen in the samples was measured. The fracture surface areas of hydrogen-induced cracking were calculated and the fracture mode was discussed. It was found that the preheating temperature of 100°C was enough to avoid cracking, even in the presence of H₂S. It was also found that the E71-T8K6 wire was more susceptible to cracking, and the typical mixed-mode fracture was predominant in all samples.     

Study on the impact toughness and diffusible hydrogen of G105 drill pipe steel in wet H2S environment

In order to investigate the influence of wet H₂S environment on impact toughness of G105 drill pipe steel, the impact test of drill pipe exposed to NACE A solution for different time was carried out. Meanwhile, the diffusible hydrogen concentration was measured to study the relationship between diffusible hydrogen and impact toughness damage. The results suggest that with the increase of corrosion time, the impact energy of G105 drill pipes decreases from 107.7 to 88.4?J, and the dynamic fracture toughness decreases gradually. The impact toughness damage increases as the diffusion hydrogen concentration increases. However, the impact energy recovery happened after hydrogen releasing. The quasi-cleavage features occur with the increasing of hydrogen concentration.     

2205双相不锈钢在酸性H2S环境下的应力腐蚀行为及开裂机理研究

_{摘要:采用C型环实验研究了2205双相不锈钢在饱和H2S环境下的应力腐蚀行为及开裂机理。研究结果表明,2205双相不锈钢在NACE标准A溶液中有良好的抗应力腐蚀能力。通过OM}、_{SEM、EDS及电化学手段分析得出2205双相不锈钢的应力腐蚀开裂经历了表面点蚀,蚀坑形成,H2S解离,H原子吸附并从蚀坑位置扩散进入金属基体,在金属基体中聚集,通过氢致开裂机制导致裂纹萌生,并逐渐扩展。}     

Effect of flow velocity on pipeline steel corrosion behaviour in H2S/CO2 environment with sulphur deposition

The effect of element sulphur on the performance of corrosion inhibitor in H₂S/CO₂ gas field solution was investigated at different velocities. The morphology and composition of corrosion products were characterised by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. The results indicated that L360 QS steel surface suffered from sulphur-induced pitting corrosion at a low velocity due to insufficient sulphur-carrying fluid power. At high flow velocities, the steel surface is likely to be suffered high fluid power which can remove the inhibitor film and corrosion scales by the mechanical erosion effect. The sulphur corrosion mechanism model and the flow-induced corrosion model due to the high wall shear force have been proposed in the study. This work suggested that the gas production rate should be controlled at an acceptable level to guarantee the service safety of pipeline system.     

Updated CO2/H2S internal corrosion model of natural gas pipelines based on flow field calculations

The ‘A line’ of the Sichuan Natural Gas East Transportation in China was used as the subject of the study, and an existing CO₂/H₂S corrosion model was utilised to predict the uniform corrosion rate. Then, the flow parameters were simulated by computational fluid dynamics based on turbulence theory, and the influence on the corrosion rate of the pipeline was analysed in a detail to more accurately describe the corrosion problems of natural gas pipelines that contain CO₂/H₂S. After that, an updated CO₂/H₂S corrosion model under the influence of flow filed was proposed by modifying the existing CO₂/H₂S corrosion model. The actual condition was calculated by the updated CO₂/H₂S corrosion model. Results show that flow parameters, namely, velocity, turbulent kinetic energy and phase distribution, affect pipeline corrosion. The flow parameters did not change significantly at the small scale changes in the pipeline (5 and 15°) of a broad and smooth flow channel of the large diameter gas transport pipeline. The shape of corrosion often appears in the form of an elliptical sheet. The corrosion location and the corrosion rate calculated by the updated model are consistent with the wall thickness detection data in the site conditions, which verified that the updated CO₂/H₂S corrosion model is valid. The updated CO₂/H₂S corrosion model influenced by the flow field can predict the corrosion distribution and the corrosion rate of the three-dimensional key positions in natural gas pipelines.     

H2S溶液中316L不锈钢TIG焊接头的腐蚀性能

文中通过极化曲线、交流阻抗、Mott-Schottky曲线、浸泡腐蚀试验等方法对316L奥氏体不锈钢TIG焊接头各区域在不同浓度H₂S溶液中的耐蚀性能进行了研究.极化曲线及交流阻抗结果表明,随着溶液中H₂S浓度的升高,焊接接头各区域的耐蚀性明显降低.另一方面对于相同浓度的H₂S溶液,316L基体的耐蚀性最好,其次是热影响区,焊缝区的耐蚀性最差.Mott-Schottky曲线结果表明,焊接接头在H₂S溶液中的表面钝化膜形成p-n结结构,掺杂浓度高达1022 cm-3,且掺杂浓度随H₂S浓度升高而增大,致使钝化膜防护性能降低.