安次地区奥陶系潜山裂缝特征及油气地质意义

针对安次地区奥陶系潜山储层非均质性强、井间生产差异性大等问题，利用岩芯、薄片及测录井等资料，对研究区内裂缝类型、发育程度及有效性进行分析，认为工区内发育构造缝、溶蚀缝和成岩缝3类，其中，构造缝最为发育，以NE走向的高角度缝为主；岩性和断层控制裂缝的发育程度，厚度薄、岩性纯、靠近断层发育的白云岩储层裂缝最为发育；张开度和充填程度反映裂缝有效性，研究区裂缝发育，多数裂缝半填充未填充，裂缝有效性好。多口井钻探证实，裂缝具有重要的油气地质意义，它不仅可以改善储层物性条件，还提供油气运移优势通道，提高单井产能，同时，裂缝的形成时期和发育部位控制油气运聚成藏：新近纪以后形成的裂缝发育程度高、有效性好；油气藏内部的裂缝发育，有利于油气运聚，形成富油气聚集区。

Fracture Characteristics of Ordovician Concealed Hills in the Anci Area and Their Significance in Petroleum Geology

To resolve issues such as high heterogeneity of reservoirs and significant yield discrepancies between wells of the Ordovician concealed hills in the Anci Area, information such as core, thin section, and logging data are used to analyze the types, development, and the effectiveness of fractures in the study area. It is concluded that there are three types of fractures in the site:structural fractures, corrosion fractures, and diagenetic fractures. Structural fractures are the most developed among the three and are mostly northeast-striking high-angle fractures. Lithology and faults control the degree of development of fractures. Thin and lithologically pure dolomite reservoirs adjacent to faults contain the most developed fractures. Aperture and degree of filling reflect the effectiveness of fractures. In the study area, the developed fractures are mostly partially filled or are unfilled, thus they are relatively effective. Drilling of multiple wells confirms that these fractures are significant in petroleum geology. They can improve the physical conditions of reservoirs and provide advantageous channels for oil and gas transfer, thus increasing yields from single-wells. Meanwhile, the formation periods and development positions of fractures control the transport and accumulation of oil and gas to form reservoirs. Fractures formed after the Neogene period are highly developed and effective. Fractures inside oil-gas reservoirs are in favour of oil and gas enrichment.