小型断陷湖盆下生上储式油成藏规律研究——以海-塔盆地中部主要断陷带大磨拐河组为例

摘要

Based on the dissection of oil reservoirs and the study of space matching relation between oil reservoirs and oil accumulation conditions,it is considered that oil reservoirs are mainly fault oil reservoirs in main central rifts of Haita Basin,and mainly distributed in reversal structures and around long-term developing faults.Oil accumulation and distribution of K1d are mainly controlled by the following factors：①Distribution areas of K1n1 source rock control the areas of oil accumulation and distribution of K1d;②Reversal structures are favorable places for oil accumulation of K1d;③Sand bodies of braided delta front provide favorable reservoir space for oil accumulation of K1d;④Long-term developing faults not only provide pathways for oil migration of K1n1 to K1d,but also provide structural background for oil accumulation of K1d.Oil accumulation models of K1d are that oil from K1n1 migrated to K1d by long-term developing faults under the action of buoyancy and accumulated in fault block or fault-lithologic traps in and around reversal structures.%通过油藏解剖及油藏与油成藏条件之间的空间匹配关系得到,海-塔盆地中部主要断陷带大磨拐河组油藏主要为断层油藏,平面上主要分布在反转构造上和长期发育断裂附近。大磨拐河组油成藏与分布主要受4种因素的控制：①南一段源岩区控制着大磨拐河组油成藏与分布的范围;②反转构造及其附近是大磨拐河组油聚集的有利部位;③辫状河三角洲前缘亚相砂体为大磨拐河组油聚集成藏提供了储集空间;④长期发育断裂不仅为南一段源岩生成的油向大磨拐河组运移提供了输导通道,而且为大磨拐河组油聚集提供了圈闭。大磨拐河组油成藏模式为：南一段源岩生成的油在浮力作用下通过长期发育断裂向上覆大磨拐河组运移,在反转构造及其附近的断块或断层-岩性圈闭中聚集成藏。