中国主要含油气盆地地球化学场特征

Characteristics of geochemical field in China's major petroliferous basins

赵克斌 孙长青

Zhao Kebin Sun Changqing

依据酸解烃甲烷、重烃和Δ的均值、变异系数,中国主要含油气盆地的地球化学场划分为高、中、低背景场以及高度非均匀场、非均匀场及均匀场。中国主要含油气盆地地球化学场总体趋势是西部(鄂尔多斯、四川盆地以西)含油气盆地高于东部含油气盆地,东北含油气盆地低于中部含油气盆地,而高于南方含油气盆地。其主要原因除与油气地质条件相关外,还取决于近地表沉积物的性质,以及地理、地貌的景观条件。在全国化探概查成果的基础上,结合已知油气藏化探异常的综合特征,在油气勘探程度相对较低的地区,选择局部综合异常强度大、多种指标相互配置好的松辽盆地中央凹陷南部的长岒断陷、西部斜坡及西南隆起钱家店断陷;周口盆地谭庄-沈丘凹陷;松潘-阿坝地区的辖曼-曼日玛-阿万仓异常区及下扬子地区的无为-和县及望江异常区为油气勘探的远景地区。并在7个盆地(或地区)化探普查成果的基础上,进一步划分了25个有利的含油气区带。

According to the methane,heavy hydrocarbons and mean Δ measured with acidolytic hydrocarbon method,and variation coefficient,the geochemical fields in China's major petroliferous basins can be classified as high,medium and low ambient fields,as well as highly non-homogeneous,non-homogeneous and homogeneous fields.As a whole,the geochemical fields of the petroliferous basins in western China(to the west of Ordos and Sichuan basins) are higher than that of the petroliferous basins in eastern China,and that of petroliferous basins in northeastern China is lower than that of the petroliferous basins in central China but higher than that of the petroliferous basins in southern China.In addition to the petroleum geologic conditions,the main causes are also related with the properties of near surface sediments and the geographical and geomorphologic landscape conditions.Based on the results of nation-wide geochemical reconnaissance surveys,and combined with the composite features of geochemical prospecting anomalies in the proven oil and gas reservoirs,areas with strong local composite anomaly and good consistence of various indexes in relatively under-explored regions are selected as prospective areas,including Changling fault depression in the southern end of central depression,western slope,and Qianjiadian fault depression in southwestern uplift of Songliao basin,Tanzhuang-Shenqiu depression in Zhoukou basin,Xiaman-Manrima-Awancang anomaly zone in Songpan-Aba region,and Wuwei-Hexian and Wangjiang anomaly zones in Lower Yangtze region.Twenty five plays have further been subdivided based on the results of geochemical prospecting in 7 basins(or regions).

10.11743/ogg20050405