长输管道运行多年后局部防腐层会出现明显劣化,外加电流阴极保护系统已不能对全管段进行有效保护,需要在欠保护区域追加牺牲阳极辅助保护.本文通过仿真计算手段研究了涂层破损率、土壤电阻率和并行管道对牺牲阳极辅助保护措施效果的影响,并以镁合金牺牲阳极进行了现场验证.结果表明:在相同的牺牲阳极保护方案下,当防腐层破损率从0.05%增加到 10%时,管道的保护效果逐渐降低,且当长输管道防腐层破损率超过5%时,添加牺牲阳极的辅助阴极保护方法效果不佳,应考虑修补或更换防腐层;随着土壤电阻率的增大,牺牲阳极保护的管道距离缩短,且当土壤电阻率超过30 Ω·m左右时,需考虑在欠保护管段部位添置外加电流防腐站的方法,以保证管道的安全运行;当目标管道涂层破损率和土壤电阻率较小时,存在防腐层质量不高的并行管道可以提高目标管道的防护效果.现场试验同样表明:镁合金牺牲阳极可为涂层破损率和土壤电阻率较小的目标管道提供有效防护,且防腐层质量不高的并行管道提高了牺牲阳极保护效果.

In view of the practical problem that the impressed current method fails to effectively protect the buried long-distance pipeline section crossingwater area, the joint cathodic protection method ofimpressed current and sacrificial anodewas used for the maintenance and treatment.Herein, the interaction law of impressed current with the magnesium alloy sacrificial anode for cathodic protection, as well as the influence of coating damage rate on the effect of joint cathodic protection, was studied through electrochemical experiments. Meanwhile, the protection effect of sacrificial anode was evaluated with finite element simulation and calculation. Besides, the laboratory research results were also verified in the field. The results show that there is anode output current at the sacrificial anode when the impressed potential is positive to the open-circuit potential of the sacrificial anode, and there is cathode input current at the sacrificial anode when the impressed potential is negative to the opencircuit potential of the sacrificial anode. With the increase of the impressed potential and the coating damage rate, the output current of the sacrificial anode decreases, the working potential shifts negatively, and the effect of cathodic protection is weakened. The cathodic protection potential of the under-protectedsection of the target pipeline near the water area could meet the-0.85 VCSE criterion under the joint cathodic protection of impressed current and sacrificial anode. Compared with the impressed current cathodic protection method, the joint cathodic protection effect is significantly improved, with the protection rate increased from 52.6% to 100%, and the pipeline potential is distributed more uniformly. Therefore, the sacrificial anode could be used as an auxiliary cathodic protection measure for the special environmental pipelines with local under-protected sections or positive potential.（10 Figures, 3 Tables, 20 References）

通过腐蚀试验、恒电流加速试验以及耦合性能试验,研究了铝合金和锌合金作为牺牲阳极材料在高温稠油输送管道中的适用性.结果表明:随着温度升高,两种阳极材料的腐蚀速率增大,实际电容量和电流效率减小,消耗率增大,使用寿命降低.在80℃条件下,铝阳极的腐蚀速率和消耗率均低于锌阳极的,且与T/S-52K管线钢的耦合电位更负,耦合电流更大,阴极保护作用更显著,而锌阳极在80℃下的工作电位高于最小保护电位,不满足GB/T 21448-2017标准的要求.铝合金较锌合金更适合作为高温稠油输送管道的牺牲阳极材料.

Aiming at the effect of temperature on the minimum cathodic protection potential, the minimum cathodic protection potential of the buried pipeline L450 in the simulated soil solution under different temperature conditions was investigated through the tests of potentiodynamic polarization and potentiostatic polarization, and the technical means such as weight loss method and anodic Tafel straight-line segment back-propagation method for achieving the best protection state of cathodic protection system, avoiding the phenomenon of pipeline corrosion perforation caused by insufficient cathodic protection and thus improving the applicability and correctness of pipeline corrosion protection scientifically and effectively. Results showed that for pipelines with operating temperature ≤40 ℃, the minimum cathodic protection potential should be EP ≤-850 mV(vs CSE, the same below). For pipelines with operating temperature ranging from 40 ℃ to 60 ℃, the minimum cathodic protection potential should be-850 mV≤EP≤-950 mV. For pipelines with operating temperature ranging from 60 ℃ to 80 ℃, the minimum cathode protection potential should be-950 mV≤EP≤-1 000 mV. The pipelines with operating temperature ranging from >80 ℃ obtained EP≤-1 000 mV.

通过模拟不同Cl-浓度的腐蚀实验,结合EDS、SEM、EIS等分析手段,研究了T/S-52K直缝钢在不同Cl-浓度环境中的腐蚀行为。结果表明,随着Cl-浓度的增加,活化区域的阳极溶解加速,促进了试样表面的局部腐蚀,使得试样表面局部腐蚀严重;但随着腐蚀产物膜的覆盖,有效反应面积减小,所以试样的均匀腐蚀速率反而变化不大。当NaCl浓度为8 g/L时,T/S-52K直缝钢电极反应过程主要由扩散控制;当NaCl浓度为20 g/L时,T/S-52K直缝钢电极反应过程由扩散和活化共同控制;当NaCl浓度为35 g/L时,试样表面电极反应过程主要由活化极化所控制。

表面热喷涂技术是防止油气管道表面发生腐蚀的重要措施.针对表面热喷涂技术的发展问题,首先对热喷涂技术的分类及发展现状进行了全面介绍,深入探讨目前油气管道行业的发展现状及实施热喷涂技术的可行性,最后对热喷涂技术在油气管道领域的应用现状进行了深入分析,介绍了表面热喷涂技术发展中存在的问题.结果 表明:油气管道表面热喷涂技术能有效防止管道产生腐蚀问题.经过多年的发展,这些技术已经取得了较大的成果,但是这些技术的应用并没有得到大面积的推广.因此,未来需要从实际出发,加强油气管道表面热喷涂技术的推广和应用.

运用电化学技术,通过电极电位、耦合电流、交流阻抗图谱(EIS)测试分析,研究埋地保温管道破损点及远离破损点处的电化学腐蚀行为.结果表明:氧浓差导致破损点及远离破损点试样的电极电位出现明显差异,即破损点处电极电位较正,作为阴极,具有阴极保护效应,腐蚀速率仅为0.159 3 mm/a;远离破损点位置电极电位较负,作为阳极,具有接触腐蚀效应,腐蚀速率均高于破损点位置,最高为0.531 6 mm/a;受到模拟介质有效距离效应的影响,距离破损点最近位置试样的阳极电流密度最大,腐蚀最为严重;随着温度升高,阴极区与阳极区的电位差和耦合电流密度增大,远离破损点的阳极区腐蚀加剧.自腐蚀电位下T/S-52K管线钢的腐蚀具有阴极浓差极化控制为主的电极反应特征;防腐保温层破损后,破损点处具有明显O2扩散控制的阴极反应特征,而远离破损点位置具有明显活化极化控制的阳极反应特征;距破损点距离越近,电荷转移电阻越低(其中2#试样R1仅为430.2 Ω·cm2),金属离子化趋势越强.

通过对模拟工况环境中耐温铝合金牺牲阳极的电化学腐蚀行为和性能参数测试,探讨其在井筒环境中的适用性.结果表明:随着温度升高,耐温铝合金阳极自腐蚀电位明显负移,自腐蚀速率增大,在20、40、60和80℃时的自腐蚀速率分别为0.1097、0.1235、0.1378、0.1835 mm/a.耐温铝合金阳极在20、40、60和80℃条件下的活化电位分别为-1108、-1105、-1082、-1022 mV;工作电位则分别为-1100、-1080、-1060、-990 mV,其值高于相应温度下的破钝电位,并且在高达80℃的条件下,工作电位也低于有效阴极保护电位,电流效率仍保持在70％以上.耐温铝合金阳极不仅能够提供良好的阴极保护效果,而且自腐蚀腐蚀速率较低.

通过固体缓蚀剂的释放率测试、缓蚀效果评价,结合线性极化、动电位极化和交流阻抗图谱(EIS)等电化学测试分析,探讨其缓蚀作用机理及在高温埋地输送管道防护中的适用性.结果表明:在管输工况条件下,固体缓蚀剂释放时间为33 d.当固体缓蚀剂加药量为5000 mg/L时,可以显著降低T/S-52 K钢的腐蚀速率,在模拟管输工况条件下,其缓蚀效率为89.16％.添加固体缓蚀剂后,T/S-52K钢的极化电阻R p迅速升高,电极反应阻力增大,自腐蚀电位显著正移,腐蚀速率明显降低;缓蚀剂成相膜层主要通过阻滞阴极电化学反应,发挥缓蚀作用.固体缓蚀剂的释放组元可在金属表面形成"成相的"膜层,随着腐蚀时间的延长,缓蚀剂成相膜层的膜阻Rm显著增大.通过简单有效的评价方法得到固体缓蚀剂的释放速率及最佳加药量,对固体缓蚀剂的实际应用具有指导意义.

采用慢应变速率拉伸(SSRT)实验,结合断口形貌分析,研究了在稠油输送模拟工况下不同阴极保护电位对Q235钢和L450钢氢脆敏感性的影响.结果表明,Q235钢的氢脆敏感性高于L450钢的.随着阴极保护电位负移,Q235钢和L450钢断口形貌逐渐由韧窝型韧性断裂向解理断裂转变,断面收缩率和断面收缩率损失系数增大,氢脆敏感性逐渐增加.在此工况条件下,Q235钢的最大保护电位应正于-1200mV,L450钢最大保护电位应正于-1400mV.

为了解决高温稠油输送管道的腐蚀问题,通过典型稠油输送管道的外腐蚀分析,结合室内试验和现场测试,明确埋地保温稠油输送管道的腐蚀原因,进而提出相应的防治措施.结果表明:检测管段在补口位置未安装防水帽,搭接片处出现明显渗水痕迹,土壤水介质沿管道渗入导致整个渗水管段中下部发生较为严重的腐蚀.腐蚀最严重部位位于管道周向135°～180°,距补口渗水处10 cm,管道最小剩余壁厚为4.54 mm,最大点蚀深度为2.51 mm,底部力学性能显著降低;阴极保护电流屏蔽、最小阴极保护电位过高,以及管道服役时间过长、管输温度高是导致该稠油输送管道发生外腐蚀的主要原因.针对该高温稠油输送管道的腐蚀原因,从阴极保护实施方式和准则、防腐层材料选择、缓蚀剂防腐以及管输技术等方面,提出了相应防治措施,可以有效地解决相关问题,为管道的设计、建设、运营提供技术支撑.

酸气回注技术已逐渐成为一种经济、环保、高效的酸气处理方法.针对顺北井区二号联油井的高含硫工况,在评价了回注酸气组分和回注条件的基础上,制定了相应的酸气回注方案.通过案例分析,阐述了酸气回注技术中地层选择、井口压力确定、压缩机选型、材料等工艺分析方法及方案制定应用技术.分析结果表明:酸气回注技术首先要考虑回注地层和井口回注压力;回注地层的选择要综合考虑地质和非地质两个方面因素;酸气回注方案制定过程中要利用相平衡原理充分脱水,防止腐蚀和水合物的生成;压缩机的选择除了基本设计外还应防止酸气在级间冷凝以及腐蚀.最终选择奥陶系地层作为回注地层,采用源头增压,四级增压方案实现酸气同层封存.

本文就机坪供油管网的特殊性操作特点进行简单的分析.

深度是测井作业中一项极为重要的测量参数,其准确性和可靠性对测量结果及油气井后续作业有着重要的影响.在现代井下测量(如探伤、找水等)中,能否时时、准确地得到井下数据的深度位置是很多测井研究者感兴趣的问题.在诸多通用测深方法中,相比于回声测深法和电阻率测深法而言,基于光电编码器的测深法在效率和准确度上占有一定优势,且不似读磁器测深法易受复杂环境下电磁场的干扰.因此,本文提出了一种高准确度光电编码器测深系统,结构简单且移植性好,可用于探伤仪及找水仪等其他测井设备上,并且在准确性和抗干扰能力上有了很大的提高和改善.

Inversion is process of explanating internal structure of the Earth using actual measurement data of strata electromagnetics in a quantitative or qualitative manner.Inversion and forward are mutual correspond.Inversion model not only can detect the veracity and reliability of forward model,but also can provide the basis for geologic interpretation,Inversion is one of the focal point and difficult point in transient electromagnetic detection.The basic principle of inversion of transient electromagnetic detection is described in detail.Applying the damped least square method approaching Mthe forward result realizes the inversion of transient electromagnetic.And then the inversion for actual stratum data is done by using software; the inversion result of Layers with different resistivity initial value can be obtained.Inversion results show that the method is feasible,and the experimental value has a little error.

Digital control logging ground system plays an important role in the exploration of oil well logging.The logging site to the actual needs and the volume of existing Inoue,and stability of many problems,,this paper presents the electromagnetic flaw detection of a based on dsPIC30F6014A MCU-based controller ground system.The article describes the design principle of the system and the hardware and software design methods.The entire system including the main control unit,power supply,data processing module,serial transmission module and so on.By boratories and oil field test verification,this ground logging system with small size,high efficiency,stability,etc..to meet works long hours and the requirements of the complex environment of the logging site.