切割法在陆东地区磁异常解释中的应用

The application of cuttingmethod to interpretation ofmagnetic anomaly in region of Ludong.

1. 浙江大学地球科学系, 浙江杭州310027;2. 中国石油勘探开发研究院, 北京100083

Department of Earth Sciences, Zhejiang University, Hangzhou 310027, China

在准噶尔盆地陆东地区的某些井中已发现有价值的油气,而且与火山岩有关。该地区的磁异常主要由火山岩引起,但当磁性体相距不远时,磁异常会互相重叠,在磁异常图上很难将它们区分开来。因此,该地区的已知含油、气井,在磁异常图上与磁异常并不对应。为此,采用切割法对磁力资料进行了处理,将不同来源的磁异常分离开来,用区域场代表深部磁性体的异常,局部场代表浅部磁性体的异常。在切割半径为4km的局部异常图上,很清楚地显示出原来与磁异常对应关系不明显的含油、气井,均位于局部异常的边缘,这表明含油、气井的分布规律与一定埋深的火山岩边缘有关。

Valuable petroleum, which is related to volcanic rock, has been discovered in some wells in Ludong region, Zhun-gar basin.Themagnetic anomalies in this region aremainly caused by volcanic rock.Whenmagnetic rocks are not far from each other, it is hard to separatemagnetic anomalies because they are usually overlapping inmagneticmap.Therefore, the relation of oil-gas holes in this region has not been exposed clearly.In order to separate themagnetic anomalies caused by differentmagnetic sources, the cuttingmethod is used in processingmagnetic data.The cuttingmethod is an algorithm for separating local field from regional field.Generally, the local field and the regional field represent themagnetic anomaly caused by the shallow and deepmagnetic source respectively.The result shows that the petroleum wells with originally unconspicuous relation tomagnetic anomaly are on themargin of local field inmagneticmap with a cutting-radius of 4 km.Itmeans that the distribution of oil-gas holes is related to themargin of the volcanic rock in certain depth.