多边形分区在石油重磁反演中的应用

Application of polygon partition in inversion of gravity and magnetic interface

（1.中国石油化工股份有限公司石油勘探开发研究院，北京100083；2.中国地质大学（北京），北京100083）

Petroleum Exploration & Production Research Institute, SINOPEC, Beijing 100083, China

在石油重磁界面反演中，Parker-Oldenburg法的应用条件是界面连续。我国南方的碳酸盐岩地区，地质条件复杂，界面不连续，通常采取重磁场分区策略来满足ParkerOldenburg法的要求。针对地质单元为不规则多边形这一特征，提出了多边形分区提取重磁数据的方法。方法的基本原理是，通过判定点和射线位置与多边形之间的关系，从原始重磁场中按多边形范围提取各个多边形分区的位场数据。应用该方法，对某碳酸盐岩地区的重磁数据进行了多边形分区提取；然后在每个多边形内应用Parker-Oldenburg法反演出各单元的基底深度；最后通过拼接，获得了整个区域的基底界面。

In inversion of gravity and magnetic interface, the applicable condition of Parker-Oldenburg method is that interface should be continuous. The carbonate area of south China is with complex geologic conditions and discontinuous interface, so partition of gravity and magnetic field is often adopted to satisfy the requirement of Parker-Oldenburg method. Aiming at the irregular polygon characteristic of geologic units, polygon partition is proposed to extract gravity and magnetic data. The principles of the method are as follows: through judging the relationship between the position of points and rays and polygons, the potential field data of every zoned polygon is extracted according to the polygon range from gravity and magnetic field. The method was applied to extract gravity and magnetic data in some carbonate area; then Parker-Oldenburg method was used in every polygon to inverse base depth of every unit; finally the basement interface of the whole area was obtained through splicing.