三维激发极化法反演研究及其在金属矿勘探中的应用

激发极化法在金属矿、硫化矿等资源勘探方面应用较广.随着勘探设备与计算机硬件的发展，所采集到的数据具有观测数据量大、布极方式多样等特点.针对实测数据的特点，我们研究完成了基于并行技术的激发极化法对数反演算法，该算法具有如下特点：（1）通过压缩存储技术和并行技术的集成实现了可以处理大数据特征的反演算法；（2）利用对数反演来约束每次计算得到新模型的电导率恒为正，充电率在0到1之间变化，从而保证反演的稳定性和可靠性.本文首先设计了两组对比模型进行试验，通过对不同区块数据采用不同加权的方式来减弱噪声对反演结果影响的效果；其次，采用并行技术提高了反演的计算速度，并利用理论模型分析了不同电极装置对反演分辨率的影响.最后，在甘肃某金属矿开发前景区利用激发极化法开展了中梯装置的采集工作，利用加权后的观测数据反演推断出了测区金属矿开发靶区的大致位置及分布特征.

Study on three-dimensional inversion of induced polarization data and applications in mineral exploration

The induced polarization tomography has been extensively used in mineral exploration, investigation of sulfide ore, and other resources detection. With the development of exploration instruments and computer hardware, the amount of observed data in field surveys is getting larger and electrode array is more diverse. Based on the characteristics of observed data, we develop an inversion strategy for the induced polarization data that integrates the parallel technology and log-barrier method. The inversion strategy has the following characteristics:(1) The inversion strategy can handle large amounts of observed data with the compression storage and parallel technology; (2) Using the log-conductivity and log-barrier methods constrain the inverse model more reasonable that the resistivity is guaranteed to be positive and the chargeability always varies between 0 and 1. We firstly conduct two groups of comparative experiments with synthetic models. The experiments aim at controlling the effects of the noise in inversion result with giving the different weighting coefficients to the datum acquired in different areas that simulate the actual situation in the field. Second, the parallel technology is adopted to improve the inversion calculation speed. Meanwhile, we study the effects of the type of electrode array on the inversion resolution with synthetic models. Last, we employed the induced polarization tomography with the central gradient array in a potential area of mineral exploration in Gansu province, the inverted maps from the inversion with different weighting coefficients shows that the approximate location and subsurface three-dimensional resistivity and chargeability distribution of the mineral developing target in the survey area are delineated.