单对电极的井下环空电磁流量测量系统的优化方法
Optimization Method of Annular Flow Electromagnetic Measurement System with One Pair of Electrodes
作者：葛亮(西南石油大学 机电工程学院, 四川 成都 610500;四川大学 制造科学与工程学院, 四川 成都 610065)；李丹(西南石油大学 机电工程学院, 四川 成都 610500)；廖俊必(四川大学 制造科学与工程学院, 四川 成都 610065)；胡泽(西南石油大学 电气信息学院, 四川 成都 610500)；韦国辉(西南石油大学 理学院, 四川 成都 610500)
Author：GE Liang(College of Mechanical and Electronic Eng., Southwest Petroleum Univ., Chengdu 610500, China;School of Manufacturing Sci. and Eng., Sichuan Univ., Chengdu 610065, China)；LI Dan(College of Mechanical and Electronic Eng., Southwest Petroleum Univ., Chengdu 610500, China)；LIAO Junbi(School of Manufacturing Sci. and Eng., Sichuan Univ., Chengdu 610065, China)；HU Ze(College of Electric and Info., Southwest Petroleum Univ., Chengdu 610500, China)；WEI Guohui(College of Sci. Southwest Petroleum Univ., Chengdu 610500, China)
收稿日期：2017-08-14 年卷（期）页码：2018,50(4):237-245
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：环空流量;优化设计;仿真优化;权重函数;COMSOL;电磁测量
Key words：annular flow;optimal design;simulation optimization;weigh function;COMSOL;electromagnetic measurement
基金项目：国家自然基金青年基金资助项目（51504211）；国家安监局2014安全生产重大事故防治关键技术资助项目（sichuan-009-2013AQ）
中文摘要
随着石油资源的不断钻采，尤其是在窄安全密度窗口地区钻井时，由于对井下流量信息的缺失，导致溢流和井喷问题。采用井下微流量控制钻井技术可以有效解决窄安全密度窗口钻井中出现的溢流和井喷问题，而使用井下环空流量测量技术实时获取井下的环空流量信息是实现井下微流量控制钻井技术的最核心部分及保证。近年来快速发展的电磁流量计研究为井下环空流量测量提供了机遇，作者基于数字优化技术对井下环空流量测量系统进行了优化研究。首先，提出钻井过程中单对电极的井下环空流量电磁测量基础理论模型和优化原理，并基于Bevir的矢量权重函数理论实现环空流道电磁流量测量系统虚电流电势和虚电流密度求解。权函数值与磁感应强度和虚电流密度有关，当电极的尺寸和结构固定时，即虚电流密度为定值，通过优化励磁结构来使权函数值接近常数。其次，为了实现井下环空电磁流量系统的最优设计，作者基于多耦合场软件COMSOL仿真模型对建立的环空电磁流量测量系统的关键结构尺寸因素进行了仿真，通过对单对线圈励磁结构COMSOL仿真数据进行分析，结合矢量权重函数的评价指标进行综合权衡，得出最优励磁结构参数。再根据不同的边界条件实现环空流道电磁流量测量系统虚电流电势和虚电流密度求解，掌握了虚电流密度分布规律。经过建立理论模型、仿真优化、分析评价指标，最终得出单对电极的井下环空电磁测量系统的最优励磁结构参数，该参数有利于提高系统的测量精度。
英文摘要
With the continuous drilling of petroleum, especially in the area of narrow mud weight window, the lack of downhole flow information may lead to the overflow and blowout arose on account of. Using the drilling technique of downhole micro-flux control could effectively solve problems of overflow and blowout which appeared in the narrow mud weight window. And the information of downhole annular flow, which was obtained through using the technology of downhole annular flow measurements, was the core part and assurance to implement the downhole micro-flux control. Based on the digital optimization technology, the system of downhole annular flow measurement was optimized. Firstly, the basic theoretical model and optimization principle of annular flow electromagnetic measurement system with one pair of electrodes were proposed. Also based on Bevir's vector weight function theory, the solution of virtual current potential and virtual current density for annular flow channel electromagnetic flow measurement system was realized. Weigh function was closely related to magnetic and virtual current density. When virtual density remained unchanged, which meant that virtual current density was a constant value,weigh function could be close to constant by optimizing the excitation structure. Secondly, the optimum design of the downhole annular electromagnetic flow system was realized, based on the Multiphysics COMSOL simulation of the factor of key structure for annular electromagnetic measurement system. According to different boundaries, virtual current potential and virtual current density for annular flow channel electromagnetic flow measurement system were solved, the distribution of virtual current density was mastered. By analyzing the COMSOL simulation data of single-pair coils excitation structure and synthetically balancing the evaluation index of vector weight function, the optimum parameter of excitation structure was obtained. Through modeling, optimizing and analyzing the evaluation index, the optimum parameter of excitation for downhole annular flow measurement system was solved to improve the measurement accuracy.
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