定向电磁波电阻率测井响应特性研究

发布时间：2018-04-29 12:57

本文选题：定向电磁波测井 + 随钻测井　；参考：《西安石油大学》2015年硕士论文

【摘要】：定向电磁波电阻率测井仪器除含有轴向天线外还含有倾斜天线或横向天线,可提供多种探测深度的相位差和幅度比,大大提高了随钻电磁波传播测量技术的定向探测能力、方位灵敏性和信息量,从而提高了该技术对未钻地层界面位置及方位的钻前预测能力,尤其适合于薄储集层导向钻进、油水界面识别、复杂地层判定预警等地质导向作业。本论文研究定向电磁波电阻率测井理论,设计定向电磁波测井仪器的线圈系参数,研究和分析各种测井环境对定向随钻电磁波测井响应的影响。研究内容主要分为以下四个部分:第一部分阐述了定向电磁波电阻率测井仪器的结构和测量原理。从电磁波电阻率测井仪器的测量原理出发,推导倾斜线圈的电磁场响应及坐标系转换公式,最终阐述了定向电磁波电阻率测井仪器测量信号的电阻率幅值比和相位差计算公式。第二部分完成定向电磁波电阻率测井仪器参数的设计。应用COMSOL有限元数值模拟软件计算定向电磁波电阻率测井仪器不同参数下的测井响应,分析仪器工作频率、发射线圈与接收线圈的倾斜角度,以及发射接收线圈间距等参数对仪器响应特性的影响,从而合理设计定向电磁波电阻率测井仪器的仪器参数。结果表明:当仪器工作频率为低频时,接收到的幅值信号小,衰减速度慢,探测范围大,但对地层电导率不敏感。均匀地层中,线圈倾斜角度越大,接收到的信号幅值越小,相位角衰减越快。当不同对比度地层存在时,可以利用交叉分量识别层界面位置和两侧电导率对比度。源距小时,接收信号受直耦信号影响大于受地层电导率变化影响。增大源距能够增加探测深度,但源距大时,接收线圈电压幅值减小,易受噪声影响。第三部分研究定向电磁波电阻率测井的井眼影响和环境影响。首先计算分析定向电磁波电阻率测井仪器8个线圈对受井径、偏心距、泥浆和地层电导率四个参数的影响特征。结果表明:仪器居中时,小源距的线圈对响应受井径、泥浆和地层电导率影响严重,大源距的线圈对所受影响较小。仪器偏心时,接收线圈R3和R4可分别探测到x方向和y方向的偏心。泥浆电导率大时,大源距的线圈对所受偏心影响较大,且随着偏心距的增大,偏心影响逐渐增大。其次计算分析了侵入和围岩环境下的定向电磁波电阻率测井响应。考察侵入和围岩的各种影响因素,结果表明:在侵入环境下,短源距线圈对接收信号的定向幅度衰减和定向相移值较大。存在围岩时,仪器测井响应受到层界面的影响。定向幅度衰减在地层交界面处尖角的峰值增大,这种现象有利于预测未钻地层界面的存在。目的层和围岩层电阻率对比度很大时,长源距线圈对定向相移在地层边界处的峰值向下翻转,在这种情况下,不能简单地利用相移来判断地层界面的存在。第四部分计算分析定向电磁波电阻率测井的电流分布特性,研究测井响应与电流分布特性的关系。通过改变地层之间电导率对比度,改变发射源在地层中的位置,仪器在井眼中的偏心距,分析得出:在井眼模型中,仪器居中时,电流密度曲线是轴对称且均匀分布的闭合同心椭圆环;仪器偏心时,电流线不对称,且随着偏心距的增大,一侧电流线越密,而另一侧电流线越疏。当仪器一侧靠近井眼边界时,井壁上产生电流的折射,使得电流线分布不规则。侵入带半径变化对电流流动产生的影响很小。存在围岩时,当仪器在目的层中心位置处、地层与围岩边界附近以及仪器处于围岩时,随着地层电导率对比度的变化,会在地层界面产生不同程度的反射和折射。当电流线以一定角度穿过地层层时,会发生折射现象。而当入射角度越来越大时或地层电导率对比度越大时,流线会出现反射现象。研究定向电磁波电阻率测井的响应特性,对自主研发定向随钻电磁波测井仪器具有重要的理论和实际意义。
[Abstract]:In addition to the axial antenna, the directional electromagnetic wave resistivity logging instrument also contains the inclined antenna or the lateral antenna, which can provide the phase difference and amplitude ratio of various depth of detection. It greatly improves the directional detection ability, azimuth sensitivity and information amount of the electromagnetic wave propagation measurement technology, thus improving the position of the non drilling interface. The pre drilling prediction ability of the azimuth and azimuth is especially suitable for the guide drilling of the thin reservoir, the identification of oil-water interface, the prediction and early warning of the complex formation. This paper studies the theory of the directional electromagnetic wave resistivity logging, designs the coil parameters of the directional electromagnetic wave logging instrument, and studies and analyzes the electromagnetic wave of directional drilling in various logging environments. The research content of the logging response is divided into four parts: the first part describes the structure and measurement principle of the directional electromagnetic wave resistivity logging instrument. From the principle of the electromagnetic wave resistivity logging instrument, the electromagnetic response and the coordinate transformation formula of the inclined coil are derived, and the directional electromagnetic wave resistance is finally expounded. The second part completes the design of the parameters of the directional electromagnetic wave resistivity logging tool. The COMSOL finite element numerical simulation software is used to calculate the logging response of the different parameters of the directional electromagnetic wave resistivity logging instrument, the analysis of the working frequency of the instrument, the launching coil and the connection. The influence of the inclination angle of the coil and the spacing of the transmitting and receiving coil on the response characteristic of the instrument, so as to rationally design the instrument parameters of the directional electromagnetic wave resistivity logging instrument. The results show that when the working frequency of the instrument is low frequency, the received amplitude signal is small, the attenuation speed is slow, the detection range is large, but the electrical conductivity is not sensitive to the formation. In homogeneous formation, the larger the angle of the coil is, the smaller the amplitude of the received signal, the faster the phase angle attenuation. When the different contrast strata exist, the cross component can be used to identify the interface position and the contrast of the electrical conductivity. The source distance is more affected by the direct coupling signal than the change of the conductivity of the stratum. It can increase the depth of detection, but when the source distance is large, the amplitude of the received coil voltage is reduced and the noise is easily affected. The third part studies the borehole influence and the environmental impact of the directional electromagnetic wave resistivity logging. First, we calculate and analyze the four parameters of the 8 coils of the directional electromagnetic wave resistivity logging instrument for the bore diameter, eccentricity, mud and formation conductivity. The results show that, when the instrument is in the middle, the small source distance coil has a serious influence on the diameter of the well, the mud and the conductivity of the formation, and the large source distance is less affected by the coil. When the instrument is eccentric, the receiving coil R3 and R4 can detect the eccentricity of the X direction and the Y direction respectively. When the mud conductivity is large, the large source distance coils are affected by the eccentricity of the coils. The effect of eccentricity increases gradually with the increase of eccentricity. Secondly, the response of directional electromagnetic wave resistivity logging in the environment of intrusion and surrounding rock is calculated and analyzed. Various influence factors of invasion and surrounding rock are investigated. The results show that the directional amplitude attenuation and directional phase shift of the received signal are larger in the intrusive environment. In the surrounding rock, the logging response of the instrument is affected by the layer interface. The orientation amplitude attenuates at the peak of the sharp angle at the interface of the stratum. This phenomenon is helpful to predict the existence of the non drilling stratum interface. The long source distance coil turns to the peak value of the directional phase shift to the boundary of the stratum. The fourth part calculates the current distribution characteristics of the directional electromagnetic wave resistivity log and studies the relationship between the logging response and the current distribution characteristics. By changing the contrast of the conductivity between the strata, the position of the source in the formation is changed, and the instrument is in the well eye. The eccentricity analysis shows that in the borehole model, the current density curve is a closed concentric elliptical ring with axisymmetric and uniform distribution when the instrument is in the middle. When the instrument is eccentric, the current line is asymmetrical, and with the increase of the eccentricity, the more dense the current line is, and the other side of the current line is thinning. When the side of the instrument is near the borehole boundary, the current is produced on the wall. Refraction makes the distribution of the current line irregular. The influence of the change of the radius of the intrusive zone on the current flow is very small. When the surrounding rock is in the center of the target layer, near the boundary of the stratum and the surrounding rock and the instrument is in the surrounding rock, with the change of the contrast degree of the conductivity of the stratum, the reflection and folding of different degree will be produced at the stratum interface. Refraction occurs when the current line passes through a layer of ground at a certain angle. The reflection phenomenon will appear when the angle of incidence becomes larger and the contrast of the formation conductivity is greater. The study of the response characteristics of the directional electromagnetic wave resistivity logging has important theory and reality for the independent research and development of directional drilling electromagnetic logging instruments. Intertemporal meaning.

【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.811

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