CAJ | 학술논문

为研究复杂井周条件下随钻电磁波测井的响应规律，优化仪器参数，开展了基于hp‐FEM 算法的随钻电磁波测井仪器响应正演研究。根据时谐电磁场理论建立数学模型，考虑边界条件建立了变分方程，采用hp‐FEM算法对仪器在二维旋转对称性地层模型中的响应进行模拟。数值模拟结果表明，均匀地层hp‐FEM 数值解与解析解相对误差仅0.0463％，验证了正演程序的精确性。在其他参数不变的条件下，发射线圈频率越大，相位差曲线变化幅度越大，且极化角所处位置越靠近真实模型的分界面；仪器的源距越小，极化角越明显，纵向分辨能力越强。相对于低阻层，仪器进入高阻层时，相位差曲线上出现的极化角较大。研究结果表明，提高频率和缩短源距可以更加精确地反映地层界面位置，为地质导向决策提供测井资料支持。
위연구복잡정주조건하수찬전자파측정적향응규률，우화의기삼수，개전료기우hp‐FEM 산법적수찬전자파측정의기향응정연연구。근거시해전자장이론건립수학모형，고필변계조건건립료변분방정，채용hp‐FEM산법대의기재이유선전대칭성지층모형중적향응진행모의。수치모의결과표명，균균지층hp‐FEM 수치해여해석해상대오차부0.0463％，험증료정연정서적정학성。재기타삼수불변적조건하，발사선권빈솔월대，상위차곡선변화폭도월대，차겁화각소처위치월고근진실모형적분계면；의기적원거월소，겁화각월명현，종향분변능력월강。상대우저조층，의기진입고조층시，상위차곡선상출현적겁화각교대。연구결과표명，제고빈솔화축단원거가이경가정학지반영지층계면위치，위지질도향결책제공측정자료지지。
In order to identify the responses of the electromagnetic logging w hile drilling (ELWD) tool under complex near‐wellbore conditions and to optimize the tool parameters ,the forward modeling of such responses was carried out based on hp‐FEM .A mathematical model was established based on the theory of time harmonic electromagnetic field ,and a variation equation built considering boundary conditions ,the re‐sponse of the instrument in a two‐dimensional rotational symmetric formation model was simulated by u‐sing the hp‐FEM algorithm .The result of the numerical simulation shows that the relative error between numerical solutions and analytic solutions is only 0.046 3% in the homogeneous formation model ,and the accuracy of the forward modeling program can be verified .When other parameters are kept constant ,the higher the emission frequency of coil ,the larger the change of the phase difference curve ,and the closer the location of polarization angle to the interface of true model ;w hen the source spacing of the instrument is smaller ,the polarization angle is more evident ,and the vertical resolution is higher .As the tool goes into a high‐resistivity zone ,the polarization angle in the phase difference curve is larger than that in the low‐resistivity zone .The research results show that the tool parameters can be optimized by increasing the frequency and shorten ‐ing the source spacing ,so as to reflect the formation interface accurately ,and to provide the support for geosteering decisions with logging data .