若尔盖地区地表油气化探的影响因素及消除方法

Factors affecting surface geochemical prospecting for oil and gas in Zoige Plateau and methods for the elimination of their effects

地表油气化探影响因素众多,不同地区主导因素也不尽相同.通过对若尔盖地区近地表油气化探原始数据特征分析,认为该复杂地貌区的化探样品分析数据差异较大,其干扰因素主要源于地形地貌和样品岩性等差异.为了研究不同地形地貌特征可能对化探指标的影响,利用地表遥感图像解译对研究区进行了地球化学景观分类,分别统计背景值,以消除不同景观条件下对化探成果的干扰影响;为了抑制不同岩性造成的干扰,运用数理统计方法,找出区域总样品数中比例大、岩性相同的原始分析数据作为标准,对全区样品进行分类,利用比值法进行校正.最后通过综合异常分析,给出了3个可能的油气远景区.

There are many factors of influencing surface geochemical prospecting for oil and gas,and the main influencing factors are different in different areas.Based on the characteristic analysis of the original surface geochemical prospecting data in Zoige Plateau,it is held that there is a great deal of difference in the geochemical prospecting data,and the difference is from the complex topography and geomorphology of the region and the difference in the lithology of the samples.For studying the influence of different topography and geomorphology on the surface geochemical prospecting indexes,the region is divided into 7 types of geologic-geochemical landscape systems by the surface remote sensing image of the region,and their background values are calculated respectively;for inhibiting the interference of lithology,by means of statistics,the original data of the samples which occupy a great percentage in the total samples and have a same lithology are found,taking them as a criterion,the total samples are classified,and then the original data are progressively corrected by the ratio method.Finally,three oil/gas prospecting zones in Zoige Plateau are presented by comprehensive abnormality analysis.