井下前视超声相控成像方法研究
文献类型：学位论文
| 作者 | 苏畅 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-05-26 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 声学研究所 |
| 关键词 | 套管损坏检测 相控阵 超声成像 阵元不一致性 |
| 其他题名 | Study of a Downhole Forward-looking Ultrasonic Imaging Method |
| 学位专业 | 声学 |
| 中文摘要 | 油田生产中，套管损坏情况的检测和评价是保障生产的一项重点工作。与现有套管检测仪器相比，井下前视超声成像系统用于对测井仪器前方的井段进行探测，在套管变形严重及有井下落物的情况下，可以有效避免阻卡仪器，并且不受井液可见度的限制，是对现有套管检测仪器的重要补充。 本文研究了井下特殊环境下的超声相控成像方法，在相控阵阵元数较少的情况下，通过一系列数字信号处理方法，得到可以反映仪器前方套管情况的图像。 本文分析了影响超声成像质量的各种因素，针对系统中存在的阵元不一致性、阵元宽度较大等问题，分别用理论计算、数值模拟进行了分析，对部分结果进行了实验验证。结果表明本文中实验系统的三种阵元不一致性对成像质量影响很小，文中提出了不一致性的控制范围；阵元宽度对成像质量的影响较大，文中提出了补偿方法。对图像中的伪像，分析了出现的原因，并提出了根据对成像模型的预期去除部分伪像的方法。 本文利用井下前视超声成像系统实验室样机，对套管模型进行了成像实验，验证了成像和补偿方法的有效性。 |
| 英文摘要 | Inspection and evaluation of casing damages is important to maintain oil production in oil fields. Compared to the existing casing damage detecting equipments, the downhole forward-looking ultrasonic imaging system can detect downward in the hole and can be used in cases of severe casing damages or falling objects, without being locked. Thus this system is a complement to existing casing damage detecting equipments. This paper studies ultrasonic imaging method for casing damage detection. Under the circumstances that the number of phased array elements is small, the image of the casing is generated via a series of signal processing, which correctly reflects the real shape of the casing. The paper analyzes the factors influencing ultrasonic image quality. The ultrasonic imaging system has the problem of element inconsistency and wide array elements. We discuss these problems by means of theoretical analysis and numerical simulation. Results show that the influences of the inconsistency among elements in our equipment on ultrasonic imaging are trivial. The tolerable ranges of these inconsistencies are given. The influence of array element width cannot be ignored. Methods to correct this influence are introduced and verified by experiments. We also analyze the cause of artifacts in the image and provide a method to reduce some of the artifacts. Using the experimental downhole forward-looking ultrasonic imaging system, we did experiments on damaged casing models. The results show that the methods introduced in this article work well. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 67 |
| 源URL | [http://159.226.59.140/handle/311008/536]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 苏畅. 井下前视超声相控成像方法研究[D]. 声学研究所. 中国科学院声学研究所. 2009. |
入库方式： OAI收割
来源：声学研究所
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