通过露头观测火山岩断层带内部结构特征，结合火山岩断层封闭机理研究与岩性对接封闭性评价，系统分析松辽盆地徐家围子断陷营一段火山岩断层带内部结构与断层侧向封闭性。徐家围子断陷火山岩断层带内部发育不同程度的破碎带和断层核“二元结构”。断层在火山岩对接处基本不具备封闭性，在火山岩储集层与上覆砾岩层及泥岩层对接处形成岩性对接封闭。通过改进传统的Knipe图（单井三角图），绘制双井三角图清晰表征走滑断层对岩性对接的影响。利用双井三角图，结合断层面岩性对接图建模对断层封闭性进行评价。研究发现，徐家围子天然气主要聚集在断层的上升盘，气水界面纵向上受控于火山岩对接的最小深度，气藏在徐中走滑断层“海豚效应”的影响下，平面上围绕断层呈“正弦”形态分布。图10表1参25%Through outcrop observation of the internal structure of volcanic fault zone and in combination with fault sealing mechanism research and lithology juxtaposition evaluation, this paper analyzes the internal structure and lateral fault sealing of a volcanic fault zone of the Xujiaweizi Fault Depression. The“binary structure”of damage zone and fault core is developed inside the volcanic fault zone. The fault does not have the sealing property basically at the juxtaposition of volcanic rock. Lithologic juxtaposition sealing is formed at the juxtaposition of the volcanic rock reservoir stratum and the overlying conglomerate bed and mudstone bed. By improving the traditional Knipe diagram (single-well triangle diagram), a dual-well triangle map is drawn to indicate the influence of strike-slip fault on the lithology juxtaposition. Modeling is established with the dual-well triangle diagram and in combination with the fault lithology juxtaposition diagram to evaluate the fault sealing property. Research showed that the gas pools in the Xujiaweizi Depression are almost in the upside of faults;in the longitudinal, gas-water contract is almost at the most shallow position of volcanic juxtaposition and the horizontal distribution of gas pools around faults is just like the curve“sine”as the result of the“dolphin effect”of the Xuzhong strike fault.
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