重力小波分析方法在宁东煤田预测中的应用

Wavelet analysis and interpretation of gravity data for predicting the coal fields in east Ningxia area

宁东地区是宁夏规模最大的含煤区,已发现9个石炭—二叠纪和侏罗纪大煤田。笔者对宁东地区1∶20万区域重力资料进行进一步处理,根据宁东含煤区石炭—二叠纪煤田与侏罗纪煤田2种类型,采用2.5D正演建立煤田重力场模型,并说明采用位场分离方法能够分离与识别含煤区;利用小波分析方法对布格重力进行分析,结果发现:小波一、二、三阶细节与已知的煤田对应较好,而滑动平均等传统的位场分离方法分离的局部异常则无明显对应关系。利用重力小波一、二、三阶细节预测了宁东地区石炭—二叠系和侏罗系含煤区的远景,充分发挥了1∶20万区域重力资料在煤田勘探中的作用。

As the largest coal-bearing area in Ningxi,the east Ningxia（ Ningdong） area has nine Permian-Carboniferous and Jurassic coal fields.According to the characteristics of these two types of coal fields in the Ningdong area,the authors established the 2.5D gravity field model from the forward modeling.The coal-bearing area could be identified and separated by the potential field separation method based on the 1 ∶200 000 gravity data.It is found that the first to third wavelet details correspond well with the known coal fields after applying the wavelet analysis to the Bouguer gravity anomaly,while the local gravity anomalies derived from the slide averaging method have no obvious correspondence with the known coal fields.Therefore,the wavelet analysis of the gravity data has good performance in predicting the Permian-Carboniferous and Jurassic coal-bearing area.And at the same time,the use of the 1 ∶200 000 gravity data is maximized for the coal field exploration.