【作者】 王鑫；

【导师】 董杰；

【作者基本信息】 上海交通大学 ， 材料工程， 2020， 硕士

【摘要】 新疆塔河油田的缝洞型油藏具有“埋藏深、温度高、易漏失、裸眼段长”等特点,需采用分层酸压完井技术开采石油。分层酸压完井技术需要将钢管柱深下至裸眼井段,但由于封隔器解封失败、井壁坍塌等因素容易造成生产阶段钢管柱卡埋,修井难度大、费用高、成功率低,因此,希望将裸眼段完井管柱及封隔器设计为可溶材料,以实现完井期间工具有效封隔,后期生产时在高温地层水环境下溶解。本文尝试选用可在高温地层水环境下溶解的铝合金制造管材,首先基于高温载荷和容许尺寸,选用管材铝合金牌号和计算管材壁厚,并进行模拟工况加载试验进行验证;然后针对4小时的高温高压强酸作业,对铝管（内壁）进行表面处理,并进行模拟工况耐酸压实验验证;最后系统研究了饱和盐水中温度、压力及时间等对铝合金管材（外壁）的腐蚀行为,为实际研制油管提供理论和应用支撑。选定质轻、高温强度高、腐蚀性差、可钻的2024铝合金作为油管材料。通过固定芯头挤压法制备了外径110mm、壁厚32mm、长度3m的油管管材。160℃下的静态力学测试表明,油管的屈服强度稳定330MPa左右,抗拉强度稳定在450MPa左右;依据强度和完井尺寸要求,经理论计算设计油管的尺寸为外径101.6mm、壁厚10mm;模拟实际工况试验表明:在拉力60t、内压50MPa、温度160℃等复合加载条件下,10mm或者15mm壁厚规格的油管均未发生变形。选定了三种耐高温酸蚀的表面处理方式:化学镀Ni-W-P、微弧氧化+热喷涂聚四氟乙烯、电镀银。试片级耐高温（100℃）强酸（20%HCl）实验结果表明,电镀银和微弧氧化+热喷涂聚四氟乙烯这两种表面涂层,在100℃、20%HCl条件下,4小时后试片质量仅损失1%左右。电镀银管材模拟实际工况验证实验表明,在100℃、30MPa、20%HCl条件下,5小时后试片质量仅损失0.5%左右。电镀银可推荐为实际油管制备的表面处理技术。不同温度、不同压力条件下,2024铝合金在饱和盐水中的失重规律研究结果表明,均匀腐蚀对温度有强烈的依赖性,温度越高,均匀腐蚀越严重,但随着腐蚀时间的延长,均匀腐蚀会逐渐减慢并最终达到一个稳定值。均匀腐蚀对压力存在依赖性,压力越大,均匀腐蚀越严重,随着腐蚀时间的延长,压力对于均匀腐蚀的影响有所变化,随着压力增加,均匀腐蚀先增加后降低。比较而言,温度是影响腐蚀失重的主要因素。经估算,外径101.6mm、壁厚10mm、长度9.5m的铝合金油管在实际工况下完全降解约需要3年。不同温度下,2024铝合金在饱和盐水中长时间浸泡的动电位极化曲线均出现了明显的“拐点”,材料发生了钝化现象。温度越高、钝化现象越快发生,但腐蚀电流越大。25℃和80℃下的腐蚀规律是一致的,浸泡初期（24小时内）,腐蚀电流很小,随着浸泡时间的延长,腐蚀电流逐渐增加,腐蚀加剧。不同温度下,2024铝合金在饱和盐水中长时间浸泡的电化学阻抗谱测试拟合结果表明,浸泡初期（24小时内）,主要是致密钝化膜形成并起到抑制腐蚀的作用;随着浸泡时间的延长,外层钝化膜发生破裂,内层形成新的膜层,继续起到物理阻隔的作用来抑制腐蚀。80℃下外层钝化膜的破坏要强于25℃且钝化膜内层的再阻挡作用也弱于25℃。XRD和XPS分析结果表明,钝化膜外层主要是氧化铝,内层主要是Al（OH）₃和AlOOH。更多还原

【Abstract】 The fracture-cavity type reservoir in Xinjiang Tahe Oilfield has the characteristics of"buried depth,high temperature,easy leakage,and long open-hole interval",etc.It is necessary to adopt layered acid fracturing completion technology to extract oil.Due to the failure of the packer to unseal and the collapse of the well wall,it is easy to cause the steel pipe column to be stuck in the production stage.Workover is difficult,expensive,and has a low success rate.Therefore,it is hoped that the open-hole completion tube and packer are designed as soluble materials to achieve effective isolation during completion and to dissolve in the high-temperature formation water environment during later production.This article attempts to select aluminum alloy pipes that can be dissolved in high-temperature formation water environment.First,based on high-temperature loads and allowable dimensions,select the aluminum alloy grade of the pipe and calculate the wall thickness of the pipe,and perform simulation load test to verify it.Then for 4 hours of high temperature,high pressure and strong acid operation,the aluminum tube（inner wall）is surface treated,and simulated acid resistance test.Finally,the corrosion behavior of aluminum alloy pipes（outer walls）based on temperature,pressure,and time in saturated brine was systematically studied.Provide theoretical and application support for the actual development of tubing.2024 aluminum alloy,which is light-weight,high-temperature strength,poor corrosive,and drillable,was selected as the material of the tubing.An oil pipe with an outer diameter of 110 mm,a wall thickness of32 mm,and a length of 3 m was prepared by a fixed core extrusion method.Static mechanical tests at 160°C show that the yield strength of the tubing is stable at about 330 MPa and the tensile strength is stable at about 450MPa.According to the strength and completion size requirements,the size of the designed tubing is theoretically calculated to be 101.6 mm outer diameter and 10 mm wall thickness;simulation The actual working condition test shows that under the combined loading conditions of tensile force of 60t,internal pressure of 50MPa,and temperature of 160℃,no deformation of the oil pipe with a wall thickness of 10mm or 15mm occurs.Three high-temperature and acid-resistant surface treatment methods were selected:electroless Ni-W-P plating,micro-arc oxidation+thermal spray polytetrafluoroethylene,and silver plating.The experimental results at 100°C and 20%hydrochloric acid showed that the quality of the test piece lost only about 1%after 4 hours of the electroplated silver and micro-arc oxidation+thermal spray polytetrafluoroethylene surface coating.Verification experiments of simulated actual working conditions of electroplated silver pipes show that under the conditions of 100°C,30MPa,and 20%HCl,the quality of the test piece loses only about 0.5%after 5hours.Electroplated silver can be recommended as a surface treatment technique for actual tubing preparation.The results of weight loss of 2024 aluminum alloy in saturated brine under different temperature and pressure conditions show that uniform corrosion has a strong dependence on temperature.The higher the temperature,the more severe the uniform corrosion,but as the corrosion time increases,Corrosion will gradually slow down and eventually reach a stable value.Uniform corrosion is dependent on pressure.The larger the pressure,the more severe the uniform corrosion.As the corrosion time increases,the influence of pressure on uniform corrosion changes.As the pressure increases,uniform corrosion increases first and then decreases.In comparison,temperature is the main factor affecting the weight loss of corrosion.It is estimated that it takes about 3 years for the aluminum alloy oil pipe with an outer diameter of 101.6mm,a wall thickness of 10mm,and a length of 9.5m to completely degrade under actual operating conditions.At different temperatures,Potentiodynamic polarization curves of the2024 aluminum alloy immersed in saturated saline for a long time showed obvious"inflection point",and the material was passivated.The higher the temperature,the faster the passivation occurs,but the larger the corrosion current.The corrosion rules at 25°C and 80°C are the same.At the initial immersion time（within 24 hours）,the corrosion current is very small.With the extension of the immersion time,the corrosion current gradually increases and the corrosion intensifies.The fitting results of the electrochemical impedance spectroscopy test of the 2024 aluminum alloy immersed in saturated saline for a long time at different temperatures show that in the initial immersion（within 24 hours）,the dense passivation film is formed and plays a role in inhibiting corrosion;With the extension of the immersion time,the outer passivation film ruptures,and the inner layer forms a new film layer,which continues to play a physical barrier to inhibit corrosion.The damage of the outer passivation film at 80°C is stronger than 25°C and the reblocking effect of the inner layer of the passivation film is also weaker than 25°C.XRD and XPS analysis results show that the outer layer of the passivation film is mainly alumina,and the inner layer is mainly Al（OH）₃ and AlOOH.更多还原