重磁多参数模拟技术及其应用——以黄桥地区LJ线处理解释为例

Gravity-magnetic multi-parameter simulation technology and its application: case study of LJ line in Huangqiao area

（中国石油化工股份有限公司华东石油局第六物探大队，江苏南京210007）

Sixth Geophysical Exploration Group, East China Petroleum Bureau, SINOPEC

重磁资料解释的精度在很大程度上依赖于地质体物性参数的正确性和构造几何形态的合理性。在实测岩石标本物性资料有限的区域，采用重磁震联合的重磁多参数模拟技术可以提高重磁资料解释的精度。方法的基本原理是：根据地震资料的解释层位建立地质体初始空间结构；通过地震波速度与地层密度的关系式求取空间密度；结合磁源深度估算方法判定火成岩的赋存与磁性基底的起伏；采用重磁多参数复合物理量模型拟合技术，通过不同物理量的拟合，调整模型地质体的密度差、磁化率差和边界，确定地质构造及其属性细节。利用该方法对黄桥地区LJ线进行了重磁观测场、高频滤波场、低频滤波场、带通滤波场、导数、梯度等物理量的一体化拟合，大大地约束了解的范围，提高了重磁资料解释的精度和可信度。

The precision of gravity and magnetic data interpretation depends, to a great extent, on the validity of physical properties and the rationality of structure-s geometric shape. In the area with limited rock samples, gravity-magnetic-seismic multi-parameter simulation technology can be adopted to improve the interpretation accuracy of gravity-magnetic data. The principles of the technology are as follows: ①the initial space structure of geologic model is established by horizons interpreted for seismic profiles; ②the spatial density is obtained by the equation of seismic wave velocity and formation density; ③the occurrence of igneous rock and the fluctuation of magnetic basement are judged by magnetic source depth estimating method; ④by fitting different physical elements, the gravity-magnetic multi-parameter simulation technology is used to adjust the density difference, magnetic capacity difference, and boundary of modeling geologic body and to identify the geologic structures as well as its attributes details. The method was used to do integrated fitting of physical elements of LJ line in Huangqiao area, including gravity-magnetic observation field, high-frequency filtering field, low-frequency filtering field, passfrequency filtering field, derivative and gradient, etc. The fitting greatly restricted the range of solutions and improved the accuracy and credibility of gravity-magnetic data interpretation.