断陷盆地内构造带对油气聚集的控制作用——以海拉尔盆地霍多莫尔构造带为例

海拉尔盆地多凹多隆,不同凹陷内的成藏规律不尽相同。以海拉尔盆地霍多莫尔构造带为研究对象,从地质背景、地震资料及重点井位资料入手,划分构造带的构造单元,识别区域内的断层和不整合面,预测主力储层的砂体厚度并刻画研究区及周缘的砂体展布范围。通过对断层、砂体和不整合与油气聚集关系的研究,认为断层、砂体和不整合是霍多莫尔构造带成藏的主控因素,并控制了构造带内不同构造单元的油藏类型、输导体系组合样式和成藏模式。构造带内的斜坡区形成砂体-不整合输导体系,主要发育岩性油藏和构造-地层油气藏;古隆起区形成断层-不整合-砂体输导体系,主要发育构造-地层油气藏和潜山油气藏;浅部走滑断层带形成断层-砂体输导体系,主要发育构造-岩性油藏。构造带内不同构造单元对应形成斜坡带成藏模式、古隆起带成藏模式和走滑断层带成藏模式。霍多莫尔构造带隆起区油气聚集受控于断层和不整合,斜坡带油气聚集受控于砂体和岩性圈闭的聚烃规律。

Hydrocarbon accumulation in rifted basin tectonic units:A case study of Huoduomoer tectonic zone in the Hailaer Basin

The Hailaer Basin is a complicated rifted basin which has various hydrocarbon accumulation distribution patterns. We identified the faults and unconformities of the Huoduomoer tectonic zone, and predicted sandstone thickness by inversion based on seismic, logging and well core data. We found that faults, sandstones and unconformities are three dominant hydrocarbon accumulation factors in the research area by analyzing the relationship among them. They not only controlled hydrocarbon migration but also impacted the accumulation process. In the slope belt, sandstones and unconformities provided hydrocarbon migration routes, and reservoir lithology and structural-stratigraphic reservoirs were developed. In the uplift area, faults, unconformities and sandstones worked as hydrocarbon migration routes, and buried hill reservoirs and shallow structural-stratigraphic reservoirs were developed. In the shallow strike-slip fault belt, faults and sandstones allowed hydrocarbon migration, and structural-stratigraphic reservoirs were developed. There are mainly three categories of hydrocarbon accumulation:slope belt mode, strike-slip fault belt mode and buried hill mode. Hydrocarbon accumulation was controlled by faults and unconformities in the uplift area, and by sandstones and lithologic traps in the slope belt.