三塘湖盆地航磁异常特征及油气远景预测

Aeromagnetic Anomaly Characteristics and Oil-Gas-Bearing Prospecting of Santanghu Basin

三塘湖盆地是我国西部典型的火山岩油气盆地。本文基于1∶5万高精度航磁资料,结合区域地质、区域重力、地面踏勘和物性资料,对三塘湖盆地进行了航磁综合解释;详细分析了磁场和重力场特征及其与区域构造的对应关系,圈定了盆地火山岩分布范围,采用欧拉反褶积方法计算了磁性体埋深,初步揭示了盆地磁性基底起伏情况;结合盆地火山岩油气成藏模式,开展了航磁油气远景预测。结果表明,三塘湖盆地中央坳陷内有隐伏火山岩存在的次级凹陷中心具有寻找火山岩油藏的良好前景:汉水泉凹陷区中的2个次级凹陷中心、条湖凹陷区北段次级凹陷中心应作为油气勘探重点区域;石头梅凸起和岔哈泉凸起区可作为重要油气勘探方向;方方梁凸起及其以南区域可作为下一步油气勘探工作的预研区。研究结果可为盆地油气资源后续勘探开发提供指导。

Santanghu basin is a typical volcanic oil and gas basin in the west of China.Based on the high precision aeromagnetic data,integrated interpretation was completed,combining with the regional geology,Bouguer gravity,field reconnaissance,and magnetic susceptibility information.Firstly,the magnetic and gravity characteristics of Santanghu basin,as well as the relationship with the structure division were described in detail;and then,the volcanics distribution range was delineated,and the magnetic basement relief was revealed with the depths of the magnetic body calculated by the Euler deconvolution method;finally,the oil-gas-bearing prospecting was conducted based on the aeromagnetic data,together with the volcanic reservoir features and hydrocarbon accumulation pattern.The sub-sags with concealed volcanics distribution in the center of Santanghu basin depression are favorable for oil reservation.Two sub-sags in Hanshuiquan and one sub-sag in northern Tiaohu are key region for oil gas exploration.Shitoumei and Chahaquan uplifts are important regions,and Fangfangliang uplift and the southern area may be the pre-study regions.The exploration direction and prospective areas presented in the paper can provide reference for the oil and gas exploration in the future.