丹青河林场-道台桥剖面的断裂及构造分区

在波数域应用重力归一化总梯度及相位法研究了4种典型的台阶模型，讨论了GH场等值线和相位曲线与台阶断面的对应关系；应用该方法对大庆探区外围丹青河林场—道台桥剖面（简称DB4剖面）野外实测的高精度重力数据进行处理，划分出8条断裂；通过与项目组大地电磁测深的反演结果进行对比，研究了依兰—依通断裂带、牡丹江断裂和勃利盆地的西缘边界断裂；综合重力与大地电磁测深数据，划分了剖面的构造分区并作出地质解释。由于断裂构造与生油凹陷的发育和油气圈闭的形成密切相关，笔者旨在研究DB4剖面的主要断裂和构造特点，从而为在大庆探区外围进一步优选油气区提供地球物理佐证。

A STUDY OF FRACTURES AND STRUCTURAL DIVISION ALONG THE DANQINGHE FOREST DAOTAIQIAO SECTION ON THE PERIPHERY OF DAQING PROSPECTING AREA USING GRAVITY AND MAGNETOTELLURIC SOUNDING DATA

Using the method of normalized full gradient of gravity anomaly and its phase in the wave number domain, this paper studied four typical staircase models, discussed the relationship between the GH field contour and the phase curve, processed the high precision gravity data on the basis of the measurements made along the Danqinghe forest Daotaiqiao section (called DB4 for short) on the periphery of Daqing prospecting area and recognized eight fractures. Through a comparison with the inversion results from the magnetotelluric method, the authors investigated Yilan Yitong fractures, Mudanjiang fractures and the west edge fracture of Boli Basin, and also summed up the gravity and magnetotelluric data to perform structural division of this section and make geological interpretation. As fractures are closely related to the formation of source depressions and the entrapment of oil and gas, the authors probed into the main fractures in the DB4 section and their characteristics so as to provide the geophysical evidence for locating the promising oil and gas districts on the periphery of Daqing prospecting area.