普光地区须家河组烃源岩特征及成烃演化过程
Characteristics of Xujiahe Formation Source Rock and Process of Hydrocarbon Generation Evolution in Puguang Area

烃源岩特征研究是成烃演化研究的基础，烃源岩地球物理预测能够有效地定量评价烃源岩特征.普光地区因可用钻井较少，难以对陆相须家河组烃源岩总有机碳(TOC)含量和厚度进行定量评价.基于烃源岩TOC体定量预测技术，对普光地区须家河组烃源岩的TOC含量和厚度进行地球物理预测.研究结果表明：须家河组主要为中等烃源岩，TOC含量约0.6%～1.5%，主要以条带状分布；须三段的有效烃源岩厚度主要为20～30m，须五段主要为30～40m；晚燕山期的剥蚀厚度约2000～5000m，从构造高部位向研究区两侧呈递减的趋势；侏罗纪末期，须三段烃源岩大部分地区进入成熟阶段，而须五段只有北部洼陷地区进入成熟阶段，达到生烃门限，现今，须三段和须五段烃源岩基本进入高成熟-过成熟阶段，主产气，成熟度由北向南递减.
The source rock characteristics, which can be evaluated quantitatively by the geophysical prediction, are the basis of the hydrocarbongeneration evolution study. However, it is difficult to carry out a quantitative evaluation of the total organic carbon (TOC) content and thickness for the source rock in Puguang area due to lack of available drillings. The TOC content and thickness of Xujiahe Formation source rock in Puguang area were geophysically predicted by the quantitative prediction technology of the TOC volume in this study. The results show that Xujiahe Formation is mainly a fair source rock with the TOC values ranging from 0.6% to 1.5%, and the distribution of the TOC content is mainly in the banded structure. The general thickness of the effective source rock ranges from 20 to 30m in Xusan Member, and 30 to 40m in Xuwu Member, respectively. The erosion thickness is about 2000 to 5000m with a decreasing trend from the high part of the structure to both sides of the study area at Late Yanshanian. At the end of Jurassic, Xusan Member source rock reached the mature stage in most areas; but for Xuwu Member, only the source rock in the northern sag reached the mature stage and the hydrocarbon threshold. At present, Xusan and Xuwu Member source rocks are basically in the high maturityover mature stage generating gas mainly, and the maturity decreases from north to south