鄂尔多斯盆地盐池地区二叠系山1-盒8段物源分析

鄂尔多斯盆地中、北部二叠系山西组-下石盒子组已发现多个大型油气田，其勘探潜力巨大。但盆地西部盐池地区山西组、石盒子组的勘探程度较低，因而弄清其物源对该区进一步油气勘探十分重要。以研究区钻测井、岩心及盆地周边露头实测等资料为基础，应用统计学方法对区内山1、盒8段石英颗粒成因类型、岩屑类型、重矿物组合、古流向及沉积相等特征进行了全面的研究。结果表明：研究区山1-盒8期沉积物受到北部及西北部物源的共同影响，且二者物源具有较强的继承性。盐池地区物源主要受到北西向的桌子山、贺兰山地区的影响；而苏里格西部地区陆源碎屑沉积物则来自北部阿拉善-阴山古陆。区内山1、盒8段主要为三角洲前缘沉积，受物源及沉积相的影响，环县区域具有汇水区的特征。

Provenance of the Permian Shanxi Formation 1st member and Xiashihezi Foratmion 8th member in the Yanchi area, west of Ordos basin

In recent decades, many large gas fields have been discovered in the Permian Shanxi Formation and the lower Shihezi Formation in the middle and North Ordos basin, indicating a great exploration potential. The 1st member of Shanxi Formation and 8th member of Xiashiheizi Formation are the principal producing formation, but their exploration degree in the Yanchi area of the western basin is very low. It is thus of great important to study their provenance for the future petroleum exploration. In this study, well drilling, logging and core data, and measurements of the surrounding outcrops were used to describe the genetic types of quartz, clastic composition, heavy minerals, paleocurrent direction and sedimentary facies of the Shanxi Formation 1st member and Shihezi Formaton 8th member in the Yanchi area by statistics. The result shows that, the sediments of the Shan 1 and He 8 members have received materials from the N and NW directions, and they have a good inheritance. The provenance of the Yanchi area was affected by the Zhuozi Mountain and Helan Mountain, while that of the west Sulige area was affected by Yin Mountain paleocontinent of the north Ordos basin. In addition, the Shan 1 and He 8 members are mainly delta front deposition, which was affected by provenance and sedimentary facies, and the adjacent areas have characteristics of catchment areas.