埕岛地区中、古生界发育两组裂缝 :一组走向为NE30° ,另一组为近EW走向。裂缝宽度为 0 3～ 2 0mm ,以中高角度缝居多。裂缝大部分形成于喜山期 ,燕山期亦有部分裂缝形成。喜山期的裂缝主要分布于埕岛地区南部和北部 ,因与油气主排烃期相匹配 ,是良好的油气储集空间及运移通道。燕山期形成的裂缝尽管早期被方解石充填 ,但由于受后期地下水溶解作用的影响 ,同样可形成有利的油气储集空间及运移通道 In Chengdao area, there are two sets of fractures in Paleozoic: one is NE30 ° and the other is near EW. Crack width of 0 3 ~ 20mm, mostly in the high-angle seam. Most cracks formed in the Himalayan period, Yanshan period also some cracks formed. Himalayan fractures are mainly distributed in the southern and northern parts of Chengdao area, which are good reservoirs and transport channels for oil and gas due to their matching with the main hydrocarbon expulsion period. Although the fractures formed during the Yanshanian period were calcite filled early, favorable oil and gas reservoir space and migration channels can also be formed due to the dissolution of groundwater in the later period