利用重磁资料研究北极地区扬马延微陆块中南部断裂构造与油气远景

Fault structure and hydrocarbon prospects of the central-south Jan Mayen microcontinent in the Arctic region based on gravity and magnetic data

1.西安石油大学地球科学与工程学院,陕西西安710065;
2.西安石油大学陕西省油气成藏地质学重点实验室,陕西西安710065;
3.海洋油气勘探国家工程研究中心,北京100028;
4.中海油国际公司勘探部,北京100027

1. School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;
2. Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi'an Shiyou University,Xi'an 710065,China;
3. National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing 100028,China;
4. CNOOC International Limited,Beijing 100027,China

为了研究北极地区扬马延微陆块中南部的断裂构造与油气远景,系统收集并整理了已有的重力及磁力资料,基于变纬度化极技术计算磁力化极异常,利用位场边缘识别技术获得相应的位场边缘识别信息,结合已有的地质及地球物理研究成果,对重磁异常及位场边缘识别信息进行深入分析,确定扬马延微陆块中南部断裂构造格架,圈定油气勘探有利区。研究认为,扬马延微陆块中南部重力高异常与重力低异常相间分布的特征反映了该区隆起与坳陷分布的范围及展布特征。扬马延微陆块中南部主要发育有北东向、北西向、近东西向及近南北向4组断裂,这4组断裂对基底结构、性质、隆坳格架及新生界分布起着重要的控制作用。扬马延微陆块中南部圈定出Ⅰ类和Ⅱ类油气勘探有利区,这些勘探有利区最显著的特征是处于自由空间重力局部异常及垂向二阶导数异常高值带,其发育明显受断裂构造控制。Ⅰ类勘探有利区对应的重力异常幅值较高、异常变化梯度较陡;相对于Ⅰ类勘探有利区,Ⅱ类勘探有利区对应的重力异常幅值相对较小、异常变化梯度相对较为平缓。

The Jan Mayen microcontinent is located to the south of Jan Mayen Island in the Norwegian-Greenland Sea of the Arctic region.To study the structural features and hydrocarbon prospects of the Jan Mayen microcontinent,we collected and collated existing gravity and magnetic data,calculated the reduction to the pole of magnetic anomalies based on the variable latitude polarization technique,and obtained edge recognition information of the potential field using edge recognition technology.Based on the results of previous geological and geophysical studies,we analyzed the features of the gravitational and magnetic anomalies and the edge recognition information of the potential field,determined the fault system,and delineated favorable areas for oil and gas exploration in the central-south Jan Mayen microcontinent.The results showed that gravity highs and gravity lows with alternative distributions reflect the distribution range and through-going features of the sags and uplifts in the central-south Jan Mayen microcontinent.Four groups of faults NE-,NW-,near EW-,and near SN-trending were primarily developed in the middle and south of the study area.These faults play an important role in controlling the structure and properties of the basement,the uplift and depression framework,and the distribution of Cenozoic strata.The favorable areas of types Ⅰ and Ⅱ for oil and gas exploration were delineated in the central-south Jan Mayen microcontinent.The most notable feature of these favorable areas is their location in the local anomaly of free-air gravity and the abnormal high-value zones of the vertical second derivative,with their development being controlled by the faults.In the favorable areas of type Ⅰ for oil and gas exploration,the amplitude of gravity anomalies is higher,and their gradient is steeper.In comparison,the amplitude of gravity anomalies in type Ⅱ areas is relatively small,and their gradient is relatively gentle.

国家自然科学基金面上项目(42172224)和陕西省自然科学基础研究计划项目(2021JM-401)共同资助。

10.3969/j.issn.1000-1441.2023.01.015