共查询到20条相似文献，搜索用时 31 毫秒
1.
Numerical simulation of resistivity logging-while-drilling (LWD) tool response provides guidance for designing novel logging instruments and interpreting real-time logging data. In this paper, based on self-adaptive hp-finite element method (hp-FEM) algorithm, we analyze LWD tool response against model parameters and briefly illustrate geosteering capabilities of directional resistivity LWD. Numerical simulation results indicate that the change of source spacing is of obvious influence on the investigation depth and detecting precision of resistivity LWD tool; the change of frequency can improve the resolution of low-resistivity formation and high-resistivity formation. The simulation results also indicate that the self-adaptive hp-FEM algorithm has good convergence speed and calculation accuracy to guide the geologic steering drilling and it is suitable to simulate the response of resistivity LWD tools. 相似文献
2.
Downhole resistivity measurements provide valuable information for geosteering and formation evaluation. It is important to understand and correct the environmental effects, such as the borehole, the tool eccentricity and the resistivity anisotropy effects, of the measurements based on fast and accurate modelling methods. A new pseudo-analytic solution for eccentric coaxial and tilted-coil antennas in the cylindrically multilayered medium with transverse isotropic conductivity was developed. This method can take the eccentric tool, the borehole, the mud invasion and the resistivity anisotropy into account. These formulas enable us to simulate the responses of the downhole induction logging tools, including induction wireline and azimuthal propagation logging-while-drilling measurements. Instead of using the prior fictitious boundary, the generalized reflection coefficients are proposed to construct the linear matrix functions to deal with the tool eccentricity. The cylindrical functions are reorganized and presented in forms of ratios. Thus, the proposed formulas obviate the overflow issue in the computation and are more stable and efficient. The proposed approach is compared and validated with other well-established methods. Simulations and case studies show that: (1) the responses of azimuthal resistivity logging-while-drilling tool are affected by the tool's eccentricity in both isotropic and anisotropic medium; (2) sine curve behaviours exist for the phase difference and amplitude ratio of azimuthal resistivity measurements along with different eccentricity azimuth. 相似文献
3.
为了提高随钻电磁波测井仪器的抗震能力,仪器传感器中所有发射与接收线圈均安装在柱状金属钻铤上的环状刻槽中,同时槽中充填高磁导率的铁氧体,以提高发射和接收效率.本文针对多环状刻槽钻铤中发射与接收线圈分布,研究建立一套随钻电磁响应的混合模拟算法.首先,根据环状刻槽几何尺寸以及轴向边界,将整个钻铤与外部的井眼和地层划分成多个不同电导率和磁导率分布的轴对称非均质各向同性层状模型,并应用混合法建立层状非均质地层中电磁场的半解析解与各个线圈上感应电动势的计算方法.其次,利用摄动原理给出随钻电磁测井中振幅比与相位差的空间灵敏度计算公式.然后,通过数值结果考察铁氧体磁导率和地层电导率变化对发射线圈的发射功率和接收线圈上感应电动势的影响,并确定各个接收线圈上感应电动势的动态变化范围,为仪器设计过程中选择合适的铁氧体提供理论依据.最后,通过空间灵敏度分布特征考察振幅比与相位差在探测特征上的差异. 相似文献
4.
随钻电磁波传播方位电阻率仪器在钻井过程中可以提供地层边界的方位及距离信息,因此在地质导向应用中发挥着重要作用,是提高油气资源开采率的重要手段.该技术是国外近十年来发展起来的前沿技术,在国内尚属空白.本文首次构思并实现了一种应用"交联天线"的随钻电磁波传播方位电阻率仪器,并从天线结构,测量原理,数据处理以及地层电阻率成像及解释等几个方面详细阐述.交联天线由极化方向正交的线圈串绕组成,同时具有方位探测和地层背景电阻率测量的功能.通过分析交联天线的电压在仪器旋转过程中的变化规律,可以计算出仪器所在地层的电阻率,判断地层边界的方位以及估算地层边界相距仪器的距离.该随钻电磁波传播方位电阻率仪器还包括用于常规电磁波传播电阻率测试的多频多测距补偿天线结构.结合地层电阻率测量及其在方位上的相对变化,可以实现对地层电阻率的全方位成像.该仪器在国内油田进行了多次实井测试,测试结果证明仪器能够在水平井地质导向中准确提供仪器所在地层的电阻率,以及地层边界方位和距离信息.已有实井测试结果表明仪器在油层(100Ωm)和泥岩(5Ωm)中的地层边界探测深度分别为2.2m和1.6m,平均误差在0.2m以内. 相似文献
5.
本文采用广义反射系数法推导了水平层状各向异性地层中电磁场的积分解析解,并利用快速汉克尔变换技术实现了三维感应仪器测井响应的快速计算.三维感应测井响应与地层水平电导率、垂直电导率和井斜角及仪器方位角同时有关,单一分量的测井曲线不能满足资料解释的需要.通过对仪器测量分量响应特征的考察,本文提出了一种基于组合量测井曲线的资料直观解释方法.数值模拟显示,交叉分量相关组合量可准确划分地层纵向边界,并可直观识别各向异性层;与单独分量相比,主分量相关组合量提高了纵向分辨率、减弱了与地层电导率参数的非线性关系. 相似文献
6.
本文给出一种双感应资料快速近似迭代反演技术. 首先建立Fréchet导数的快速算法，保证在反演过程中能够同时获得测井响应相对于地层电阻率和层界面的偏导数，并给出用规范化处理与奇异值分解技术进行迭代反演的具体过程. 为了对理论模拟和井场实际资料进行反演，利用综合分层技术从双感应曲线中提取层界面初始位置和地层电阻率初值，通过单独迭代反演中感应资料，修改层界面和地层电阻率实现中感应资料的最佳拟合，得到探测深度相对较浅的地层电阻率，然后固定层界面位置，再迭代反演深感应资料，得到另一组探测深度相对较深的地层电阻率. 理论和实际资料处理结果证明，两个不同探测深度的电阻率反演结果的相对大小能够准确地反映地层真实的侵入特征.此外，由于深感应仪器具有较深的探测深度，不论在高侵或低侵地层上，深感应反演结果与地层原状电阻率的差异大大小于视电阻率的差异，所以利用反演结果也能得到更好的地层原状电阻率的估计值. 相似文献
7.
Sofia Davydycheva 《Geophysical Prospecting》2011,59(2):323-340
I study the responses of two different triaxial induction tools to invaded dipping anisotropic formations. I show that the triaxial measurements have generally higher sensitivity to the radial invasion profile, compared to the conventional induction measurements. This enables accurate interpretation of both the anisotropic formation properties and the invasion parameters. Multi‐spacing and single‐spacing multi‐frequency triaxial induction tools can both be used for this purpose. Failure to take the invasion properties into account may lead to misinterpretation of the vertical formation resistivity. Symmetrization of the apparent conductivity matrix opens ways for a visual interpretation of triaxial induction logs for the formation and the invasion zone properties. This technique enables simpler and faster inversion algorithms. I study how the effect of a conductive annulus forming around the invasion zone couples with effects of the dipping anisotropy and the dipping boundaries and show when these effects are additive. Thus, a visual detection of log parts affected by a conductive annulus becomes possible. The key tool for interpretation in complex 3D scenarios is efficient modelling software. I use a 3D finite‐difference modelling approach to simulate responses of induction logging tools of the new generation. Its high efficiency enables simultaneous multi‐spacing and multi‐frequency computing of the tool responses to arbitrary 3D anisotropic formations that made the study possible. 相似文献
8.
用有限差分法计算各向异性介质中多分量感应测井的响应 总被引：16，自引：5，他引：11
感应测井电阻率是砂泥岩储层中定量评价含油气性的主要参数之一,然而由于储层电各向异性的存在,传统的感应测井仪得到的电阻率主要响应地层的水平电阻率,比地层的垂直电阻率小,由此计算的含水饱和度偏高．多分量感应测井则可以通过不同方向的发射和接收,测量多个分量,弥补上述缺陷,为储层的含油气性评价提供准确信息．本文用交错网格有限差分法导出了主轴各向异性介质中Maxwell方程的离散化关系式,计算了三维各向异性介质中多分量感应测井的电磁响应．利用三层模型的数值模拟,分析了不同磁场分量对各向异性介质的响应特性,用多层模型和倾斜各向异性地层的响应计算检验了所编制的交错网格有限差分法程序． 相似文献
9.
本文针对中国石油集团测井有限公司(CPL)三维阵列感应测井仪器(Three Dimensional Induction Tool,TDIT)的真实结构与参数,利用2.5维数值模式匹配技术研究建立水平层状非均质TI地层中仪器偏心情况下三维感应测井响应的高效数值模拟算法.首先,利用2.5维数值模式匹配技术给出水平层状非均质TI模型中偏心磁流源并矢Green函数的半解析解.在此基础上,结合三维阵列感应测井仪器参数以及测量过程中出现的仪器偏心与旋转等实际情况,通过叠加原理推导出该仪器响应的有效计算公式.最后,通过数值模拟结果分析考察仪器偏心、仪器自旋角等参数对测井响应的影响以及变化特征,为多分量感应资料处理与解释提供理论基础. 相似文献
10.
There exist different response characteristics in the resistivity measurements of dual laterolog (DLL) and logging while drilling (LWD) electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method (3D-FEM) simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis. 相似文献
11.
采用偏心状态下柱状成层各向异性(横向各向同性)介质中并矢Green函数的解析表达式高效模拟多分量感应测井仪器在井眼中偏心时的响应.为提高精度,在模拟时考虑到了金属心轴、绝缘保护层的存在以及各分量线圈系的具体形状.数值模拟结果表明,当井眼内钻井液电导率相对较高、地层电导率相对较低时,偏心对仪器响应的影响较大,尤其是对短线圈距线圈系的影响更为明显,必须进行偏心效应校正.当钻井液电导率相对较低时,偏心对线圈系响应的影响可忽略不计.对位于相对低电导率井眼中的线圈系而言仪器方位角的影响可忽略不计,而当线圈系位于相对高电导率井眼中时仪器方位角的影响极为明显.当仪器偏心率较小时线圈系的响应随仪器方位角的变化较小,仪器偏心率越大线圈系的响应随仪器方位角的变化越明显. 相似文献
12.
本文将应用2.5维数值模式匹配算法研究建立柱状横向同性地层中偏心条件下磁流源并矢Green函数的高效算法,并利用该算法高效计算多分量阵列感应井眼校正库.首先,通过Fourier展开技术将偏心条件下磁流源并矢Green函数的数值模拟转化为一系列的轴对称问题;然后利用模式匹配算法求解轴对称问题,得到柱状介质中偏心条件下磁流源并矢Green函数的半解析解;最后,结合中国石油集团测井有限公司开发的三维感应测井仪器(TDIT)的结构参数,推导出复合线圈系视电导率张量的计算公式.在此基础上,根据井场实际地层资料归纳出理论地层模型相应参数的变化范围,高效高精度建立一套直接应用于工业生产的多分量阵列感应井眼校正库,并利用井眼校正库详细地分析考察各模型参数对TDIT响应的影响. 相似文献
13.
含洞穴地层随钻电阻率测井响应自适应hp有限元数值模拟(英文) 总被引：1，自引：1，他引：0
含洞穴的碳酸盐岩地层具有强烈的非均质性及储集空间预测难度大的特点,利用随钻电阻率测井方法对井眼环境含洞穴的储层进行准确识别和划分,是当前研究的一个焦点问题。本文使用一种新型的高效和高精度自适应有限元方法(hp—FEM)模拟和分析了含洞穴地层随钻电阻率测井仪器响应。本文所提的hp-FEM与传统h-FEM相比,其结果具有网格自适应的特点,并且计算能够以指数速率收敛于较高的精度。数值实例使用自适应有限元方法研究地层中洞穴的大小、洞穴距离井眼的远近和仪器发射频率改变对测井响应的影响,并提供了识别含洞穴地层的方法。研究结果可以为实际测井中遇到的各种地层洞穴的准确识别和定量评价提供理论依据。 相似文献
14.
对一种新型随钻电阻率测井仪器在均质地层中的电磁场分布和接收线圈的响应特性进行分析，并对仪器在真空中的刻度方法进行研究.推导出了圆柱坐标系下径向成层介质中磁流源并矢Green函数的矢量本征函数展开式，从而得到研究该仪器电磁场分布、接收线圈响应、刻度方法所必需的解析计算式.计算发现，钻铤的存在大大提高了仪器的定向探测性能.计算还发现，不同的钻铤尺寸、线圈系到钻铤不同的距离对线圈系在真空中的响应值具有较大影响.钻铤在地层中产生的实部信号可近似认为恒定，而当地层电导率大于001 S/m时，钻铤在地层中产生的虚部信号亦可近似认为恒定.数值计算表明，仪器偏心程度越大，钻铤半径越大，仪器中刻度环电阻所对应的视电导率值越小. 相似文献
15.
应用三维非均匀交错网格有限差分程序模拟了多极子随钻声波测井的波场,考察了硬地层中单极子随钻声波测井响应及软地层中声源频率对多极子随钻声波测井的影响;计算了接收阵列波形的时域相干谱及频散特征,结果表明随钻测井仪器居中时,在硬地层中可以直接利用单极子声系得到地层横波速度,但地层纵波受到钻铤波的极大干扰.而在软地层中可以利用单极子声系直接测得地层纵波速度,但地层横波速度则需要使用工作在较低频率下的四极子随钻声波仪来测得,此时测井频段又会落入钻井噪声频带而受到影响.为此本文提出数值模拟手段结合物理实验的方法得到钻铤波的影响,在实际测井中通过信号处理方法而不是用在仪器本体上刻槽的方式来更完全地消除钻铤的影响.为了避免钻井噪声的影响,本文提出六极子随钻声波仪更适合软地层的横波测量.本文用数值实验结果来说明这些方法的可行性. 相似文献
16.
The positive and negative difference of deep and shallow resisitivity in formation without invasion is caused mainly by the fixed two tool constants from numerical simulations. A dynamic calibration method for tool constants is proposed based on the effects of the mud and formation resisitivity ratio on the two constants calculated using the finite element method (FEM). Finally, four specific examples are given to validate the dynamic calibration method. It is an automatic borehole correction method and can give more accurate formation resistivity. The method is useful for dual laterolog logging. 相似文献
17.
The transfer function between the vertical and horizontal components of geomagnetic field variations is studied and the frequency responses of its parameters are presented. The relation to geoelectric heterogeneities of the medium is analyzed. The coast effect is considered and a deep curve of the apparent electrical resistivity constructed on its basis is used for estimating the depth to the asthenospheric conducting layer. The behavior of the induction vectors in the frequency-time domain is studied. Specific features of the behavior of the real and imaginary parts of the induction vector related to geoelectric heterogeneities of the medium are determined. Monitoring results are compared with time moments of earthquakes of K = 13?14 at epicentral distances of up to 150 km. 相似文献
18.
随钻单极子纵波测井时存在很强的钻铤波的干扰.针对这一问题,提出了一种双源反激随钻声波测井方法,从数据采集环节对钻铤波进行压制;在后续数据处理中结合声波干涉法,从而实现一种无需隔声装置的随钻声波测井方法.理论模拟表明双源反激方法可以有效压制钻铤波,地层波的信噪比也能得到相对增强.对钻铤波压制后的数据进一步用声波干涉法处理可以从中提取地层纵波信息.设计了实验样机,并在空气中进行了实验.结果表明不同工作频率下该方法对钻铤波均有明显的压制效果,即使在5kHz低频情况下钻铤波也能压制到原来的25%.验证了该方法的可行性.应用该方法的好处是可以避免对钻铤强度的破坏,并能扩展现有随钻声波测井仪纵波测量的工作频带范围. 相似文献
19.
用矢量有限元法模拟和分析了电各向异性倾斜沉积岩层的随钻测井电磁响应,为很好地模拟钻铤、井眼和激励线圈等,采用了基于圆柱坐标下的六面体剖分;同时采用了高阶叠层矢量基函数来描述每个剖分单元内的场,有利于减少剖分单元数和未知量.三维有限元程序采用数值模式匹配(当处于简单地层时)以及时域有限差分法计算的结果进行了验证,显示吻合非常好.最后仿真了不同各向异性系数和不同倾角的各向异性地层的随钻电阻率测井响应,有助于对各向异性及地层倾角的校正,以及对储层作出正确评价. 相似文献
20.
本文研究轴对称地层中高分辨率阵列侧向测井(HRLA)的多参数信赖域反演方法.首先对前期HRLA的有限元正演方法进行改进,提出基于叠加原理和并行直接稀疏求解器PARDISO的快速正演方案,更适合于反演计算.将HRLA反演问题转化为非线性最小二乘问题,利用信赖域算法求解.为提高反演速度,推导了目标函数对优化参数偏导数的具体计算公式.对典型地层模型,与已有文献中Jacobi预条件共轭梯度法(JCG)计算结果比较,发现PARDIDO比JCG快10倍以上,验证了本文正演程序的正确性与高效性.利用信赖域算法求解了电阻率四参数反演和传统的三参数反演.研究结果表明:并行直接稀疏求解器PARDISO能有效求解此类HRLA正演问题,对6次不同探测深度的测井模拟,所形成的有限元刚度矩阵完全相同,只须进行一次矩阵分解,大大加快了正反演的速度.信赖域算法收敛速度快,且具有全局收敛性.HRLA的信赖域反演结果几乎不依赖于初值的选取,从较差初值出发仍能得到满意的反演结果.另外信赖域算法抗噪能力比较强,即使对测井数据添加信噪比为10dB(甚至5dB)的高斯白噪声,仍能通过反演得到较为准确的地层参数. 相似文献