济阳坳陷孤岛与埕岛潜山油气差异富集原因分析

济阳坳陷孤岛潜山和埕岛潜山油气富集程度差异悬殊，目前原因尚不清楚。在相关研究的基础上，通过分析烃源岩有机地化、储盖层物性等特征，对孤岛、埕岛潜山油气成藏条件进行对比并剖析造成油气差异富集的控制因素。研究表明，孤岛潜山和埕岛潜山被多个生烃洼陷所环绕，两者均具有充足的油源；孤岛潜山溶蚀孔洞、裂缝发育差，导致油气向潜山内部充注效率低；而埕岛潜山溶蚀孔、洞、缝发育好，油气向潜山内部充注效率高，故潜山储层特征差异是导致两潜山油气差异富集的主要原因；孤岛潜山东营组遭受剥蚀，潜山顶部风化壳储层与馆陶组下段砂体直接接触，潜山风化壳圈闭缺少有效遮挡条件，导致潜山油气可以在剥蚀处进入馆陶组，缺失了潜山成藏的保存条件，与之相比，埕岛潜山发育良好盖层，为油气聚集提供了遮挡条件，保障了规模性潜山油气藏的形成。 

ANALYSIS ON THE CAUSES OF DIFFERENT ENRICHMENT OF HYDROCARBON IN GUDAO AND CHENGDAO BURIED-HILLS, JIYANG DEPRESSION

There are obvious differences between Gudao and Chengdao buried-hills in the degree of hydrocarbon enrichment, and the reason leading to such differences is still unclear. Base on relative researches and the organic geochemical characteristics and reservoir properties, the conditions of hydrocarbon accumulation occurred in Gudao and Chengdao buried-hills were compared, and controlling factors leading to the differences were analyzed. Both Gudao and Chengdao buried-hills are surrounded by hydrocarbon generation sags. Hence they both have favorable hydrocarbon source conditions. The dissolved pores and fractures in Gudao buried-hill are sparse, which causes low hydrocarbon charging efficiency in this buried-hill. It is such characteristics that lead to low hydrocarbon enrichment degree in Gudao buried-hill. In contrast, the dissolved pores and fractures in Chengdao buried-hill are enriched and the hydrocarbon charging efficiency is relatively high, which are also beneficial to form big pools in Chengdao buried-hill. Furthermere, the Dongying formation in Gudao buried-hill was eroded. Compared with Chengdao buried-hill, the Dongying formation''s sealing ability is relatively poor in Gudao buried-hill, and the top of Gudao buried-hill is directly connected to the sandstones of the lowest section in the Guantao formation. As a consequence, hydrocarbon could enter into the Guantao formation through the sandstones, and therefore it is hard to form reservoirs in Gudao buried-hill. In comparison, the caprock sealing ability is favorable in Chengdao buried-hill, providing effective places for hydrocarbon accumulation and availing the formation of reservoirs.