含硫气田腐蚀研究现状

综述了目前含硫化氢气田的腐蚀机理、H2S/CO2共存条件下腐蚀行为、多相流腐蚀等方面的研究现状,并提出为了安全开发高含硫化氢气田,必须开展高浓度H2S和高浓度CO2体系腐蚀机理和在H2S/CO2的腐蚀环境中多相流腐蚀的研究工作,同时建立高含硫化氢环境的试验评价标准和适应高含硫气田腐蚀预测模型.     

高酸性气田钻井中钻具的选材评价

以高含硫化氢聚合物钻井液为腐蚀介质,考察了温度、流速、pH值、PCO2/P2S分压比对S135和G105高强度钻杆钢的腐蚀影响,并对腐蚀产物形貌和成分进行了分析.结果表明,腐蚀速率随温度的升高而增大,在60～80℃间,腐蚀速率略有下降,温度超过120℃后,腐蚀速率变化不明显;流速对腐蚀速率影响不大;pH值越低,腐蚀越明显;在本试验范围内PCO2/PH2S分压比对腐蚀速率影响不大;气相腐蚀速率高于液相腐蚀速率,这与常规酸性钻井液中液相腐蚀速率高于气相腐蚀速率相反.硫化物应力腐蚀试验表明,钻杆强度越高其临界应力越低.钻杆的抗硫性能依次为G105(C)＞G105(D)＞S135(B)＞S135(A),此方法可为国内在开发高酸性气田时合理选取井下钻具管材提供参考.     

仪表制造用金属材料抗硫化氢腐蚀的室内评选结果

前言仪器仪表是保证工艺线安全高产及实现自动化控制的重要组成部分。在含硫天然气田的开发过程中,由于气体中存在着相当数量的硫化氢与二氧化碳对材料的电化学腐蚀,以及负荷应力和介质的共同作用[1],     

美国开发醋酸纤维素膜脱硫技术

天然气因产地不同,其成分的差异很大:有的几乎是纯甲烷,有的则不同程度地含有二氧化碳、氮或硫化氢。当只含氮和二氧化碳时,由于两者均无燃烧值,因而会对天然气起稀释作用,从而降低其热值;当含硫化氢时,则因本身及其燃烧产物有毒,故所有三种杂质均须予以脱除。况且,二氧化碳和硫化氢是酸性的,增加了腐蚀输气管线及其辅助设备的危险。输气管线内天然气中的二氧化碳含量的上限一般低于2％,但硫化氢的含量十分低,约4ppm(体积比)。     

S135钻杆断裂原因分析

通过化学成分分析、力学性能测试、显微组织分析等手段对某断裂失效的S135钻杆进行了材质理化检验;采用SEM和EDS分别对断口形貌及表面腐蚀产物成分进行了分析。结果表明：该钻杆的材料性能符合APISpecSD规范要求,钻杆断裂的主要原因是硫化氢应力腐蚀开裂,并伴有一定程度的二氧化碳腐蚀。     

基于点蚀的316L不锈钢在酸性气田环境中的适应性评价

国内外酸性气田的开发使腐蚀环境越来越苛刻,为满足气液混输的工艺要求,发展了耐蚀合金/碳钢的双金属复合管技术。316L不锈钢被广泛用于双金属管的内衬,在含H_2S和CO_2环境中腐蚀速率很低,然而在高含Cl-的溶液中,316L不锈钢容易出现点蚀而诱发集输管线失效,为此,就316L不锈钢在酸性气田集输环境中的点蚀进行评述。讨论了影响316L不锈钢点蚀的材质因素,Mn和Fe的硫化物及Mg、Al、Ca的氧化物等两种夹杂物均能促进钝化膜的溶解而引起点蚀;分析了316L不锈钢点蚀的H_2S、CO_2、温度、Cl-浓度和pH值等环境的适应性条件,发现H_2S环境比CO_2环境更容易发生点蚀,H_2S和CO_2对点蚀发生存在协同机制,温度升高、Cl-浓度增加和酸性介质均会增加316L不锈钢点蚀的敏感性。为进一步优化选材原则,需重点加强环境因素的协同机制、环境适应性的边界条件、点蚀发展的动力学以及新的标准研究。     

深井钻具失效原因分析与预防对策

钻具服役条件恶劣,是钻井设备工具的一个薄弱环节,特别是在深井、超深井及复杂地质环境下钻井,钻具失效事故时有发生。如果不加以预防及处理就可能造成钻井周期延长,钻井效率下降,从而造成经济上的巨大损失。本论文首先从理论的角度总结深井钻具失效的机理,提出预防深井钻具失效的措施,对提高深井钻井速度,降低钻井成本有重要意义。     

探讨钻具管理中存在问题与对策

钻具一般是野外作业的主要工具，因为钻具工作历时长、工作环境是恶劣，所以钻具失效是最常见的问题之一。频繁发生钻具失效事故导致工程的经济效益损失惨重。对钻具失效的原因进行全面分析，及时发现问题，并对此采取相应的钻具管理措施，才能有效制止钻具失效的事故发生，从而提高经济效益。     

高酸性腐蚀气田用BG2250-125镍基合金油管开发

综述了高酸性腐蚀气田用BG2250镍基合金油井管国产化开发进展情况。通过与国外同类产品的实物质量分析以及成分、电弧炉冶炼、电渣重溶、锻造、热挤压、冷轧、特殊扣设计与加工、腐蚀评价等工艺技术的研究,宝钢开发的BG2250-125等镍基合金油管的产品质量达到了国际同类产品的先进水平,并已在普光气田成功下井使用,为我国高酸性气田的开发提供了重要的物资保障。     

油井管失效分析预测预防技术进展及发展方向

介绍了石油管材失效分析及预测预防工作发展概况,在石油管材失效分析预测预防程序与方法、钻具失效预测预防技术、套管和油管失效分预测预防技术进展等方面的主要技术进展,根据钻具和套管失效概况及原因分析,提出了研究思路与主要研究方向.     

On the Causes of Corrosion Fracture of Industrial Pipelines

It is established that the most active corrosion components in gas-water-oil environment are hydrogen sulfide, carbon dioxide, oxygen, and mineral salts (especially chlorides). The main types of corrosion fracture of the metalware of oil and gas objects, in particular, industrial pipelines, exploited under severe climatic conditions, are static and cyclic hydrogen fatigue, sulfide cracking, and local (pitting and groove) corrosion.     

A study on axial cracking failure of drill pipe body

Frequently happening drill pipe failure accidents in oil and gas wells not only affect drilling speed, but cause enormous economic losses and many safety issues. Most of these accidents are transverse cracking of drill pipe body and pin thread or axial cracking of box thread. Based on the axial cracking failures of drill pipe body in an ultra-deep well in China, this paper give a systematic analysis of axial cracking failure in consideration of service condition, material quality and stress corrosion mechanism. Measurement and inspection are performed on macroscopic and microscopic morphology of crack surface, corrosion products and circumferential residual stress. Then stress corrosion cracking experiments against hydrogen sulfide is conducted. Finally, the critical stress value for sulfide stress corrosion cracking of the drill pipe material is obtained, and the mechanisms of axial cracking failure and corresponding preventive measures are proposed.     

Failure analysis of monel packing in atmospheric distillation tower under the service in the presence of corrosive gases

We have performed a failure analysis on a monel packing material subjected to sulfidation and sulfide stress cracking after a short period of service in an atmospheric distillation tower containing corrosive gases. Optical macroscopic inspections show that the failed packing material was basically covered with dark scales and corrosion products. Energy dispersive X-ray spectroscopy and X-ray diffraction spectrum show that the corrosion products contain sulfur as the main element along with oxygen indicating that oxidation may have been taken place beside sulfidation. Metallography of the failed samples reveals that cracks exist and were initiated on the surface from defects most likely developed due to the formation of porous and brittle sulfide layer accomplished by hydrogen embrittlement. Although nickel base alloys are an appropriate candidate owing to their high corrosion resistant in corrosive atmospheres, however, presence of H₂S, HCl, O₂ and naphthenic acid in crude oil lead to reduction in corrosion resistant of the monel 400 alloy.     

Experimental Study on Mechanical Properties Degradation of TP110TS Tube Steel in High H₂S Corrosive Environment

The research on casing corrosion in sour environment by a synergism of sweet corrosion and H₂S corrosion has become the basis of casing selection and casing string safety evaluation with more and more sour reservoirs containing high H₂S concentration being developed. It is essential to scientifically utilize casing service ability and reasonably control production rate of gas well to achieve the effective and safe developing of gas resources during the safety period of casing service with a precise casing life prediction. Scanning electron microscopy and tensile testing were applied to investigate the corrosion of TP110TS tube steel in stimulant solution with carbon dioxide (CO₂) and hydrogen sulfide (H₂S) at variable conditions of P_CO2/P_H2S, temperature and time. This paper especially focused on the degradation of mechanical properties (elastic modulus, yield strength and tensile strength) of test specimens subjected to corrosion. Experimental results suggest that the fracture mode will transit from ductile fracture before corrosion to brittle fracture after corrosion and the mechanical properties will experience obvious degradation when the specimens were exposed to corrosive environment. Service life prediction model of casing was established on the basis of experimental observations and results.     

Influence of Oxygen and Hydrogen Sulfide on the Carbonic-Acid Corrosion of Welded Metal Structures of Oil and Gas Equipment

We study the influence of oxygen and hydrogen sulfide on the carbonic-acid corrosion of welded metal structures of oil and gas equipment, propose a scheme for the classification of the processes of carbonic-acid corrosion in carbon steels, and establish the equilibrium conditions for the formation of corrosion products.     

基于腐蚀时间效应的含H_2S/CO_2环境中的腐蚀速率预测模型

高含H_2S/CO_2高温高压气井中井筒油管、套管的腐蚀已成为制约井筒完整性的主要因素,一旦井筒完整性失效将会给油气田的开发造成重大影响,并可能导致严重的人员安全、环境及经济损失。由于高温高压H_2S/CO_2环境腐蚀机理较为复杂,国际上使用较为广泛和经典的DE Waard腐蚀速率计算模型已不能预测类似高温高压复杂环境下井筒的腐蚀速率。目前,实验室通常开展短期的腐蚀测试试验,并以此数据预测长期的腐蚀速率,但长期的腐蚀速率与短期腐蚀速率差异甚大。因此,为了准确地预测服役寿命周期内油套管的腐蚀状况,采用自主设计制造的高温高压材料损伤试验平台,模拟气井井筒的实际腐蚀环境,开展CO_2、H_2S腐蚀环境中的电化学腐蚀速率测试试验,研究了不同测试时间下的腐蚀速率,分析了腐蚀速率的时间效应。结果表明:在管柱服役早期,其腐蚀速率较大,随着服役时间的延长,由于形成了腐蚀产物膜以及腐蚀性气体浓度的降低,腐蚀速率逐渐降低直至稳定于某一较低值。最后,利用数理统计方法建立了考虑腐蚀时间效应的腐蚀速率预测模型,可为合理选择油套管材质和油气井的安全评价提供依据。     

食品添加剂二氧化碳中硫化氢标准物质分析方法及性能评价的研究

介绍了用日本岛津GC-2014气相色谱仪,火焰光度检测器（FPD）分析食品添加剂二氧化碳中硫化氢（H2S/CO2）气体标准物质的实验原理、方法和条件.用所建立的分析方法和条件对H2 S/CO2气体标准物质色谱分析方法的精密度、方法的线性度进行了考察.H2S/CO2气体标准物质量值（1～10）×10-6（mol/mol）范围内,方法精密度≤1.1％;线性误差＜±1.0％.文中还给出该气体标准物质的性能评价（均匀性、稳定性、随压力的稳定性变化）的计算方法和实验结果.     

Pipeline failures in corrosive environments – A conceptual analysis of trends and effects

Pipeline corrosion is a major challenge facing many oil and gas industries today because of the enormous downtime associated with corrosion related failures. Fatigue stress initiation in pipelines has been attributed to corrosion defects whose growth is enhanced by cyclic loading caused by the operating pressure of the transported fluids. This work reviews the concept of oil and gas transmission pipeline failures in corrosive environment by highlighting the corrosion mechanisms, dominant stress corrosion cracking trends, hydrogen induced cracking and predominant models for burst pressure estimation. Fatigue stress failure trends of corroding pipelines were also explained whilst describing some pipeline manufacturing processes that increases the susceptibility to fatigue stress failure. Optimization framework for pipeline integrity assurance against corrosion fatigue failures was also shown to incorporate different steps that includes – strategic policy initiation, policy implementation, information analysis and reviews and implementation actions.     

Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d(-1) and 1.33 d(-1) as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.