某井套管柱泄漏原因分析

某井在固井试压过程中发生套管柱泄漏事故,随后进行了找漏、挤水泥堵漏和测井检查作业,结果显示多根套管接头泄漏导致套管柱密封失效。通过综合分析套管柱泄漏特征和地面水压试验结果认为,套管柱泄漏的原因是套管接头现场上扣端上扣质量不合格,密封性能差所致。     

139.7mm×7.72mm J55低压气密封螺纹套管接头性能

对自行设计的139.7mm×7.72mm J55低压气密封螺纹套管接头进行了上卸扣、热循环气密封、弯曲条件下气体内压拉伸、拉伸至失效、加内压至失效等试验。结果表明:该接头的抗粘扣性能良好;135℃,35MPa条件下的气密封性能和低压30MPa、弯曲狗腿度10°/(30m)、拉伸载荷为80%材料名义屈服强度条件下的气密封性能均合格;接头的泄漏失效内压和抗拉强度均远高于标准技术要求。     

吉林油田套损井状况及检测技术

由于套管受到外力、化学腐蚀等因素的作用而引起套管变形、损坏、直接影响油田油、气产量及注水效果、油井使用寿命。随着国内外套损井数量越来越多,套管损坏状况检查已经越来越重要了。套损井的检测及预防已成为油田开发中的重点工作。吉林油田套损治理也迫不容缓。本文简单介绍了吉林油田套损情况及现有检测技术。阐述吉林油田套损检测技术取得的成绩以及今后发展的方向。     

塔里木油田非API油、套管失效分析及预防

对塔里木油田非API油、套管的失效情况进行了统计分析,总结了油、套管常见的失效形式及失效原因,并针对每种失效形式提出了一定的预防措施。结果表明:套管压力升高主要是因油管接头泄漏所致,而油管接头泄漏主要是因为其气密封性能不能满足油田实际工况条件,套管挤毁失效主要与套管磨损地层蠕变有关,套管断裂和开裂既与套管材质有关,也与套管磨损有关;通过制定严格的油、套管订货技术标准,可有效预防和减少塔里木油田非API油、套管失效事故的发生。     

双丝堵密封结构检测方案研究

该文通过对双丝堵密封结构形式、密封原理与传统密封形式进行比较,说明其密封性能优势,并论述其加工特点,针对性地研究分析其加工检验方法、合格判定指标以及检验工具的设计,从而确定其最优检测方案;通过方案论证更深层地分析在实际大批量生产制造中,丝堵密封结构批量化检测手段以及在液压试验、泄漏检测试验、氦检过程中对双丝堵密封结构检测、分析、判断,对其密封性能提供双保险,为保证产品质量稳定性、可靠性奠定坚实基础。     

外压直压法摄像机气密性检测系统的设计

针对传统的直压和差压气密性检测方法难以实现对全密封器件的泄漏检测,提出了一种外压直压法摄像机气密性检测方案.在介绍外压直压法检测原理及相关气密性公式的基础上,设计了一种针对摄像机密封性能的检测系统,并搭建了实验样机.摄像机气密性实验测试结果表明,该系统可以快速、准确且稳定地检测出摄像机的大漏、小漏及合格等指标;系统检测周期少于40s,为全密封器件的气密性检测提供了解决思路.     

塔里木油田非API油套管技术要求及标准化

通过对塔里木油田油套管在使用过程中发生的失效事故和油套管订货技术标准进行分析,认为依据油套管使用工况确定订货技术标准,严格订货技术标准有利于减少油套管失效事故,统一技术标准是油田和油套管生产厂家共同的责任,统一技术标准不仅有利于油田降低采购成本,有利于油田管理和减少库存,也有利于大多数生产厂家和油套管国产化。在油套管订货技术标准中,应当对油套管的尺寸精度、材料性能、抗粘扣性能、密封性能等提出具体要求。最后介绍了塔里木油田在第三套井身结构中套管技术要求及标准化成功的案例。     

油田套损井的一种修复技术

在油田长期开发和注水过程中，油、气、水井套管损坏成为严重困扰和长期制约开采的瓶颈。近年来，我国油田各种井套管损坏的速度呈直线上升趋势，给油田造成了巨大经济损失，同时也降低了油田开发效果和原油采收率。本文针对套管损坏原因进行了分析，提出了相应防治措施井口悬挂小套管固井技术，取得了明显的防套变效果。     

DN2-6井套管压力升高及油管接头粘扣原因分析

对DN2-6井套管压力升高原因进行了系统调查研究,对起出的油管接头逐根进行检查,发现1根油管穿孔、多根油管粘扣,并对油管粘扣原因也进行了分析。结果表明:套管压力升高的原因主要是由油管穿孔所致;油管粘扣的原因主要是由对扣操作不当所致;粘扣会降低油管接头的密封能力,但该井粘扣的油管接头并没有发生泄漏,其原因是在油管穿孔泄漏之后,油管柱所受的内压很小,没有达到粘扣油管接头的泄漏抗力。     

利用套后成像测井技术分析某井套管泄漏原因

某井套管柱试压发生了泄漏,随后对套管柱进行了套后成像测井(IBC),根据测井结果分析了影响套管泄漏的因素。通过分析套管磨损对其承压能力的影响,认为套管泄漏与套管内壁磨损有很大关系;依据测井原理对套管泄漏位置进行了分析,认为IBC测井无法直接准确判定较细的套管穿透裂纹的确切位置,只能给出磨损最严重、最有可能发生漏失的位置;通过分析固井质量对使用寿命的影响,认为套管柱多处磨损后发生了椭圆变形,与固井质量不好,套管受到非均匀载荷有关。     

长庆油田渗氮套管的耐腐蚀性能研究

针对长庆油田油井套管腐蚀问题,采用并评价了真空渗氮工艺.该工艺处理套管表面形成氮化层,在不降低原有机械性能的前提下提高了表面耐磨、抗蚀能力.经室内、现场试验发现,渗氮管在长庆油井腐蚀情况下的耐腐蚀性能优良.此外,还就渗氮层在不同弯曲、拉应力条件下的微观表面变化对使用性能的影响进行了研究,确定了渗氮套管下井条件.并于2003年首次在2口井得以应用.该工艺为低产低渗透油田的防腐蚀研究提供了新思路.     

High-performance lift augmentation dynamic seals for turbine bearing compartments

Conventional bearing shaft seal systems used in gas turbine engines are often limited to a sliding velocity of about 100 m/s, differential pressure of 3 bar, gas temperature of 300°C and a seal life less than 8000 h. Advanced engines will require bearing shaft seal systems to operate up to sliding velocity of 200 m/s, differential pressure of 6 bar, gas temperature of 500°C and seal life in excess of 30?000 hours. For seals operating in these advanced conditions, a design with no rubbing contact will be required to achieve long life and reliability. A good validated approach is the use of a gas lift augmentation seal. The design objective for a seal of this type is to have the faces of the seal seek an equilibrium position to avoid any contact. The gap must be small enough to ensure a minimal air leakage, but it must be large enough to limit power dissipation, due to shear in the gas film, and face deformation by shaft displacement, misalignment and vibration. Dynamic seals for a bearing compartment have the following main functions: provide static and dynamic sealing in order to prevent oil leakage from the bearing oil compartment to the air compartment and consequently no oil smell pollution by the use of bleed air; control air leakage to the bearing oil compartment in order to improve performance of the engine and to reduce oil consumption; reduce volume of the oil tank and lubrication system and hence provide weight reduction; to operate in extreme conditions of temperature and with normal and reverse pressure; and reduce the mean time between overhaul (MTBO) and have a very long life. Techspace Aero and Burgmann have carried out design, development and testing of lift augmentation carbon seals and demonstrated that high life and performance levels of these seals are possible in a gas turbine engine environment.     

Compressor seals for hydrogen recycle service

Hydrogen recycle service has presented a special challenge for centrifugal compressors and particularly the casing seals, mainly because of contamination from process gas. This feature, reproduced with permission from the Turbomachinery Laboratory, reviews a simplified process to identify the sources of contaminants affecting both dry and wet seals. It lists precautions for the application of dry seals in this service, and discusses improvements to materials used for a wet seal design. Finally, it highlights two case histories where retrofits with the improved liquid film seal have significantly reduced sour seal oil leakage rates.     

分布式光纤管道泄漏检测及预警技术灵敏度分析

针对管道安全存在的问题,提出了一种基于Mach-Zehnder光纤干涉仪原理的分布式光纤管道泄漏检测及预警技术,利用与管道同沟敷设的光缆中的3条单模光纤构成分布式光纤微振动传感器检测管道沿线的振动信号,可以有效地检测管道沿线所发生泄漏和异常事件．分析和研究了检测系统的测试灵敏度影响因素,并采用不同光缆结构和埋设方式对检测系统的检测灵敏度进行测试．实验结果表明,该检测技术可以检测到1m范围内的人工挖掘信号,在气体管道压力不小于0．2MPa的条件下,可以检测到0．4m^3／min的气体管道泄漏．     

Numerical and experimental distribution of temperature and stress fields in API round threaded connection

Thread galling is one of the main failure forms for oil tubing and casing connections, and it leads to deterioration of seal performance and connection strength of oil tubing and casing directly. A series of full-scale tests were performed on samples of API J55 steel grade non-upset tubing threaded connections. The temperature and stress field distributions of the tubing threaded connection were measured dynamically under the action of different make-up and break-out torque and velocity. Major factors, which affect the distributions of temperature and stress fields of tubing connections, were studied and their effects on thread galling failure were summarized with friction-wear theory. The FEA models of tubing threaded connections are validated by comparing the numerical results with the full-scale tests. The validated models are afterwards used to perform parametric studies on the connection behaviour.     

Stimstream等孔径深穿透射孔弹在页岩气井中的应用

针对套管孔眼大小不一致造成页岩气井水力加砂压裂施工难度大的问题,从国外引进了一种Stimstream等孔径深穿透射孔弹,分析了其结构特点,并和国产射孔弹进行了地面环靶试验和现场应用效果比较。结果表明:该射孔弹套管孔眼受射孔枪和套管间隙大小影响不大,对降低水力加砂压裂破裂压力和施工压力具有明显的效果。     

单金属密封的结构优化及其密封性能研究

针对油气田勘探中,复杂的钻井工况导致动密封工作性能极不稳定的问题,结合单金属密封结构和井底高压环境,利用有限元方法对单金属密封受压情况下的接触压力进行分析。用雷诺方程计算单金属动密封的泄漏率,以减小最大接触压力和泄漏率为优化目标,利用正交试验和F评价方法对单金属密封结构参数进行优化,得到密封结构参数对密封面接触压力和泄漏率的影响情况,并将每个水平数对应的优化目标计算结果分别取平均值,得到不同水平影响下接触压力和泄露率平均值的变化趋势,从而确定密封结构的最优水平值,并借助有限元仿真对优化前后的密封性能进行对比。最后根据优化前后的密封结构参数加工2套密封试件,进行密封实验。仿真分析和实验结果表明：高压工况下优化前的密封面内侧磨损严重,钻井液颗粒容易侵入密封面;而优化后密封面的最大接触压力有所降低,动密封面的最高温度和泄漏率明显降低。研究结果对改进单金属密封的工作性能、提高井下动密封的可靠性有重要的现实意义。     

薄膜透气性测试装置3层密封结构的研究

基于压差法的薄膜透气性测试装置,在压力和温度检测器的检测性能给定和环境温度相对稳定的情况下,影响测试结果的主要因素是测试装置的密封性能。为了同时提高测试装置的密封性能和测试精度,提出了3层密封结构设计的模型,建立了相应的数学模型,并给出了因泄漏而引起压强变化的特性和仿真结果。为3层密封结构薄膜透气性测试装置的实际应用提供了理论依据。     

Influence factors of X80 pipeline steel girth welding with self-shielded flux-cored wire

For girth weld of high-pressure oil and gas transmission pipeline, there is impact toughness values deviation phenomenon with self-shielded flux-cored semi-automatic welding technology. The macro-images, microstructure and mechanical performance of girth welding joint have been investigated by OM, SEM, TEM. The results show that there are several factors of impact toughness unqualified values of weld joints, such as welding heat input, coarse grain zone and a chain of M–A organisations, Al₂O₃ and Zr Precipitates particle sizes and distribution et al., which are the main unqualified reasons of welding impact toughness of the semi-automatic self-shielded core butt welding process of X80 pipeline steel.     

某井特殊螺纹套管脱扣和粘扣原因分析

对某井φ177.8mm×10.36mm 110特殊螺纹接头套管脱扣和粘扣原因进行了分析,认为套管是在严重粘扣之后才发生脱扣的,套管严重粘扣主要与下井操作不当有关。在套管起吊过程中没有螺纹保护器保护的套管接头螺纹、扭矩台肩和密封面容易被损伤,不使用对扣器直接对扣容易导致偏斜对扣;不引扣而直接开动套管钳高速上扣很容易导致粘扣和错扣;一旦严重粘扣和错扣,套管接头连接强度就会大幅度下降,最终导致套管在上提过程中发生脱扣事故。