中原油田注入水腐蚀因素及控制研究

根据中原油田注水水质监测数据，采用灰关联分析方法，对文一联、文三联、濮三联三处注水体系的腐蚀因素进行了分析。灰关联分析结果知：影响文一联注水体系腐蚀的主要因素是：悬浮固体、矿化度、pH、∑Fe和溶解氧含量；影响文三联注水体系腐蚀的主要因素是：∑Fe含量、悬浮固体、溶解氧、pH和矿化度，影响濮三联注水体系腐蚀的主要因素是：pH、矿化度、溶解氧、悬浮固体和∑Fe含量。并且确立了这些因素对中原油田注水体系的影响程度。针对这些主要影响因素，提出了调整pH值、加强沉降过滤以及注水体系的密封性等改善水质的主要措施和运用QC原理的水质控制流程。     

陕北某天然气处理厂回注水处理系统腐蚀影响因素研究

目的考察陕北某天然气处理厂回注系统的腐蚀情况,保证系统安全生产。方法在水质分析的基础上,用现场材质20#钢和计划替换钢材L316研究回注水处理系统的腐蚀现状,随后选择腐蚀最严重环节的水样为介质,采用静态失重法考察温度、pH值、溶解氧、细菌对20#钢材腐蚀速率的影响。结果陕北某气田气井产出水的总矿化度较高(30 000 mg/L左右),其中Ca²⁺、Mg²⁺等金属阳离子的含量较高,腐蚀速率随水介质中溶解氧含量的增加均呈上升趋势,在80℃、溶解氧为5.07 mg/L时,腐蚀速率最大,达到0.4001mm/a。随着细菌含量的增大,腐蚀速率上升,腐蚀速率由0.1065 mm/a(TGB 60个/m L,SRB 6个/m L)增加到0.2155 mm/a(TGB 6×10~4个/m L,SRB 6×10~3个/m L)。pH值为5.9时,腐蚀速率为0.3039 mm/a;当pH值为8.5时,腐蚀速率降至0.0710 mm/a。结论通过做好回注水处理系统pH调节、杀菌和隔氧等工作,可以减轻系统的腐蚀。     

双河联合站回注水系统腐蚀因素

腐蚀速率的控制是采油污水回注水质控制的重要指标之一。本工作应用静态分析法分析了双河联合站回注水系统的腐蚀因素,探讨了无机离子种类、离子交互作用、溶解氧、pH、温度变化对腐蚀速率的影响。结果表明,单位浓度阳离子腐蚀速率的顺序为Na+相似文献   

大港油田采油装置腐蚀机理研究

大港油田油藏温度差异大,地层水性质变化大,南部油田腐蚀率高于中北部数倍,尽管采取了较多措施,但腐蚀率仍然较高,因此,需要对其进行研究并寻求相应的对策。采用差点法在9个联合站取样分析水中各种离子和微生物浓度,用静态和动态法研究了含有细菌和无细菌条件下的腐蚀速率、矿化度和硫酸盐还原茵（SRB）的浓度关系等。结果表明,南部油田地层水矿化度最高（35g／L）,硫酸根含量为50—150mg／L,SRB数量虽然低于10^2 cell／mL,但是腐蚀率高于标准值71％;中北部油田的情况却相反;在SRB存在的情况下,腐蚀率较无菌条件下高73％,产出水适宜微生物生长,水的pH和Eh都有不同的变化规律。由于南部的矿化度较高,腐蚀主要原因是电化学腐蚀,微生物腐蚀占有重要的比例。产物电镜分析表明,无菌和含菌条件下主要成分为Fe、S化合物和碳酸钙类。通过不同浓度SRB与腐蚀率的实验,获得了SRB对腐蚀的贡献率,提出了控制SRB数量指标,减少SRB数量和腐蚀的初步对策。     

中原油田文一联至柳屯油库输油管线腐蚀调查

对输油管线内、外腐蚀情况进行了调查和腐蚀因素的分析：管线输送介质为脱水原油，长期运行形成管道底部污水沉积，污水介质偏酸性，含有大量硫酸盐还原菌（SRB）、腐生菌（TGB）和碳酸氢根、氯离子腐蚀促进剂，造成内腐蚀穿孔；管线外壁防护层一半以上老化破损，且土壤含盐量高，电阻率低，pH低，造成管道外腐蚀穿孔。建议对管内投加适当的化学药剂，管外补加阴极保护。     

大港油田注水管线腐蚀机理研究

大港油田的油藏温度和地层水的性质差异较大,虽然采取了很多的措施减缓注水系统管线腐蚀,但是南部地区的腐蚀速率仍较中北部高许多,因此找出问题所在很有必要。对油田所属9个注水站现场取样分析了水的性质,用静态和动态的方法分析了未灭菌和灭菌状态下腐蚀速率与盐度和硫酸盐还原菌(SRB)数量的关系。结果表明,南部地层水矿化度较高,硫酸根含量达到50-150mg/L,SRB数量不足102个/mL,但腐蚀速率较标准值高71%,中部和北部油田却相反:无菌条件下腐蚀速率高73%,注入水适合微生物生长,pH值和氧化还原电位变化规律却不同。南部油田水因矿化度高,电化学腐蚀占主导地位,此外,微生物的腐蚀也是比较明显的。电镜分析表明,腐蚀产物主要是铁、硫化物和碳酸钙。通过SRB数量和腐蚀速率实验得到了SRB对腐蚀影响,提出了控制SRB数量降低腐蚀速率的指标。     

中原油田气举井油套管腐蚀因素分析

采用XRD,EPMA和硫酸盐还原菌（SRB）检测对中原油田气举井文13－127套管及文13－257井油管腐蚀产物及管材和两口井的水质进行分析,并试验了碳钢在含CO2介质中的腐蚀,研究结果表明,CO2及高矿化度产出水是气举井腐蚀的主要原因,油管丝扣处存在的缝隙,套管钢材中夹杂物的局部分布及流体冲刷是加剧油套管局部腐蚀穿孔破坏的另一原因,同时还探索了应用缓蚀剂防止气举井CO2腐蚀的可能性。     

宝浪油田污水腐蚀性研究

为了摸清宝浪油田污水系统腐蚀的原因,开展该项试验研究工作。采用XRD分析、X射线衍射、电子探针和电化学试验方法,、研究了该油田含油污水处理系统主要设备腐蚀产物、腐蚀形貌和腐蚀原因,并对腐蚀影响因素进行了试验研究。研究结果表明该油田污水处理系统中设备主要存在CO2腐蚀、O2腐蚀和SRB腐蚀,同时通过一系列试验证实：改变含油污水的pH值、温度和SRB含量等对污水的腐蚀性有不同程度的影响。通过本试验研究找出了该油田污水腐蚀主要原因及其影响因素,为该油田污水系统防腐蚀提供了参考。     

X80管线钢在硫酸盐还原菌作用下的腐蚀行为

目的 通过实验模拟硫酸盐还原菌（SRB）对X80钢的腐蚀,探究硫酸盐还原菌的腐蚀过程。方法 通过细菌培养实验,计数得到固着SRB和浮游SRB的生长曲线以及溶液中pH值的变化曲线。通过腐蚀电化学测试,研究了SRB对X80腐蚀的影响。通过浸泡实验,获得SRB对腐蚀速率的影响。采用扫描电镜和激光共聚焦显微镜对SRB腐蚀后的表面形貌和最大点蚀深度进行了分析,利用EDS和XPS对腐蚀产物的成分进行了分析。结果 在接种SRB的溶液中,X80钢表面固着的SRB比浮游的SRB多;随着培养时间增长,溶液pH增大。接种SRB环境中,X80钢阻抗和线性极化电阻均小于无菌环境中的值,有菌环境中腐蚀电流密度大于无菌环境中的值。随着浸泡时间增长,最大点蚀坑深度变深。通过EDS能谱分析发现,在含有SRB的环境中,S元素和O元素的含量较无菌环境中高,XPS结果表明,SRB环境中腐蚀产物多为Fe的硫化物。结论 固着SRB使试样表面的铁溶解为铁离子,铁离子与溶液中的硫酸根离子在SRB生命活动的作用下生成铁的硫化物,从而促进了X80钢的腐蚀。     

延长油田某区块采出水腐蚀因素分析及对策

介绍了延长油田概况。选取了某区块采出水进行了腐蚀因素分析,该区块采出水的特点是：Cl-、HCO3-含量较高,溶解氧、SRB、TGB含量较少,不含CO2和H2S,pH值介于6.12~10.84之间,与其它油田比较,总矿化度较高。明确了该区块腐蚀的原因是Cl-、HCO3-含量较高,加之存在溶解氧、SRB、TGB,多种因素共同作用、相互影响、相互促进造成的结果。提出了要解决油田腐蚀问题不光要加强技术研究更重要的是要加强管理的建议,为延长油田今后生产系统的防腐工作提供了借鉴。     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.