基于蒙特卡罗方法的脉冲中子地层多元素测井研究

发布时间：2018-04-08 12:08

本文选题：地层元素测井　切入点：LaBr3:Ce晶体　出处：《东华理工大学》2017年硕士论文

【摘要】：近年来,随着常规油气的开采量逐年下降同时对油气的需求不断加大,人们开始重视非常规油气储层勘探和开采,一项新型的技术诞生——地层元素测井。地层元素测井是一种利用中子源和地层元素发生相互作用放出γ射线来确定元素含量,进而评价地层的中子伽马测井技术。地层元素测井作为一种全面评价储层的新技术,可以准确得到地层矿物成分,在识别复杂岩性方面得到广泛应用,已经成为非常规油气储层识别和沉积环境及页岩气储层勘探领域的重要手段。经过调研发现,目前国外成熟掌握此项技术的测井公司主要有三家,分别是斯伦贝谢、哈里伯顿和贝克休斯公司,而我国的地层元素测井起步较晚,为了打破国外对我国的技术垄断,我国于2012年成功研制出地层元素测井样机。但是,国内还没有一套可以应用到实际测井中的标准元素谱,缺少一套完整的俘获能谱解析的方法和软件。本文的重点就是研究纯净标准能谱的获取和能谱解析算法。本文从整个测井原理上推导了测井的理论计算公式,借助蒙特卡罗程序MCNP搭建平台测井模型,首先分析研究了不同类型探测器和测井仪参数对测量能谱的影响,目的在于获取理想的元素标准谱。根据推导的公式,确定解谱过程中所需要求解的三个重要参数,分别是元素相对产额、相对灵敏度因子和地层因子。采用最小二乘法,详细介绍了三个参数的求解过程,即解谱算法。最后利用以上解谱方法,联合已获取的各元素标准谱和地层元素混合谱,求解地层元素质量百分数,通过与实际元素含量比对,验证解谱算法的准确性。通过伽马能谱响应影响因素研究,选择LaBr3:Ce晶体作为探测器,可以获得更高的测量精度;优化了测井仪各项结构参数,达到最佳的探测响应;通过能谱数据处理得到的元素含量与实际含量对比发现,基本一致,证明了所采用的解谱算法的可行性。
[Abstract]:In recent years, with the decline of conventional oil and gas production and the increasing demand for oil and gas, people begin to pay attention to the exploration and exploitation of unconventional oil and gas reservoirs.Formation element logging is a kind of neutron gamma logging technology, which uses the interaction of neutron source and formation element to release 纬 ray to determine element content and then evaluate formation.As a new technique for comprehensive reservoir evaluation, formation element logging can accurately obtain formation mineral components and be widely used in identifying complex lithology.It has become an important means of unconventional oil and gas reservoir identification, sedimentary environment and shale gas reservoir exploration.Through the investigation, it is found that there are mainly three logging companies abroad, which are Schlumberger, Halliburton and Baker Hughes, while the formation element logging in our country started relatively late.In order to break the technology monopoly of foreign countries, China successfully developed the formation element logging prototype in 2012.However, there is no standard element spectrum which can be applied to actual logging in China, and a complete method and software for the analysis of capture spectrum is lacking.The emphasis of this paper is to study the acquisition and analytical algorithm of pure standard energy spectrum.In this paper, the theoretical calculation formula of logging is derived from the whole logging principle, and the platform logging model is built with the help of Monte Carlo program MCNP. Firstly, the influence of the parameters of different types of detectors and logging tools on the measurement spectrum is analyzed and studied.The aim is to obtain the ideal standard spectrum of elements.According to the derived formula, three important parameters which need to be solved in the process of resolving the spectrum are determined, namely, the relative yield of elements, the relative sensitivity factor and the stratigraphic factor.Using the least square method, the process of solving the three parameters is introduced in detail, that is, the despectral algorithm.Finally, using the above method, combining the standard spectrum of each element and the mixed spectrum of stratigraphic elements, the mass percent of formation elements is solved. The accuracy of the algorithm is verified by comparing with the actual element content.Through the study of the influencing factors of gamma spectrum response, the LaBr3:Ce crystal is selected as the detector to obtain higher measurement accuracy, and the structural parameters of the logging tool are optimized to achieve the best detection response.It is found that the element content obtained by energy spectrum data processing is basically consistent with the actual content, which proves the feasibility of the proposed despectral algorithm.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13;P631.81

【相似文献】