摘要
该文首先从研究区内岩石的磁性、密度测量结果出发,阐述了利用重磁方法圈定火山岩的可行性。然后利用频率域滤波和边界增强技术,获得由石炭系火山岩引起的剩余重磁异常及其垂向二阶导数和Tilt导数,据此划定出研究区内火山活动带,并根据准噶尔地区火山机构岩相模式和重磁异常的对应关系,在各火山活动带内圈定火山机构。同时以剩余重磁异常的视密度和视磁化率反演结果为基础,结合重磁异常的组合情况和实测岩石物性数据,确定研究区内火山岩岩性分布情况。最后利用磁力数据开展欧拉反演,定量了解研究区火山岩的埋深情况,并在地震数据的约束下,选择典型剖面开展二维重磁联合正演,刻画剖面地质结构和火山岩垂向分布。总之,通过重磁异常研究,获得了火山岩及其岩性的空间分布情况,为后续进一步的火山岩油气勘探提供了依据。
In this paper, first the feasibility of delineating the volcanic rock distribution by gravitational and magnetic methods is discussed based on the magnetism and density of the various rocks in the study area. Then the residual gravitational and magnetic anomalies caused by the Carboniferous volcanic rocks, as well as their vertical second-order and tilt derivatives are calculated with frequency domain filter and boundary enhancement technique. In light of the calculated results, the volcanic activity zones in the study area are delimited. Furthermore, we delineate the volcanic edifices in each volcanic activity zones according to the correlation between the lithofacies patterns and the characteristics of the gravitational and magnetic anomalies in the Junggar region. In the meantime, based on the inverse modeling of apparent density and apparent magnetic susceptibility for residual gravitational and magnetic anomalies, we infer the measured petrophysical data, and the spatial correlation of the gravitational and magnetic anomalies, we infer the lithological distribution of the volcanic rocks. Finally, the burial depth of volcanic rocks is quantitatively estimated by the results of the Euler deconvolution of the magnetic data. With the constraints of seismic data, 2 D gravitational and magnetic joint forward modeling is also conducted in typical profiles to depict the vertical geological structure and the distribution of the volcanic rocks. The distribution of the volcanic rocks and their lithologies derived from gravitational and magnetic data provide a basis for the further hydrocarbon exploration in the volcanic rocks.
出处
《高校地质学报》
CAS
CSCD
北大核心
2017年第4期677-687,共11页
Geological Journal of China Universities
基金
国家科技支撑计划项目(2015BAB05B00)
关键词
准噶尔盆地
重磁异常
石炭系
火山岩
欧拉反演
Junggar Basin
gravitational and magnetic anomaly
Carboniferous system
volcanic rocks
Euler deconvolution
