潍北凹陷输导体系及其对油气成藏的控制作用

输导体系作为油气运移的通道,对油气成藏具有重要作用.通过对潍北凹陷断层及其活动、沉积体系与不整合面特征等的分析,提出研究区存在砂体、断层和不整合面等多种输导体系要素,并组成断层-不整合及断层-不整合-砂体等复合输导体系.潍北凹陷主要有2个供烃区,发育于北部洼陷带和灶户断鼻带;灶户断鼻带断裂构造比较发育,北部洼陷带断裂构造较少;潍北凹陷主要发育6个不整合面,其中Ng/Es4（Ng/Ek1）及Ek2下/Ek3为区域性不整合面,它们均导致不同地区的输导体系类型及分布有所不同.通过对潍北凹陷油气藏类型和输导体系特征进行分析,总结了不同输导体系类型对油气成藏的控制作用.潍北凹陷砂体输导体系有利于形成岩性尖灭油气藏和砂岩透镜体油气藏;断层输导体系有利于形成地层不整合-断层油气藏、断块油气藏和构造-岩性油气藏;断层-不整合输导体系有利于形成断块油气藏、岩性油气藏及断层-岩性油气藏;断层-不整合-砂体输导体系有利于形成岩性尖灭油气藏、地层不整合油气藏、断块油气藏和断层-岩性油气藏.该研究结果对明确输导体系控藏模式和指导潍北凹陷油气勘探均具有借鉴作用.

Pathway system and its controlling on hydrocarbon accumulation in Weibei Sag

As the passageway of hydrocarbon migration, the pathway system is very important for hydrocarbon accumulation. In terms of the research of fault and its activity, depositional system and unconformity in Weibei Sag, we put forward that there are three kinds of pathway system factors including sand body, fault and unconformity surface. They formed fault-unconformity pathway system and fault-unconformity-sand body pathway system. Weibei Sag has two hydrocarbon source areas which are located at the northern depression belt and eastern Zaohu faulted- nose belt. The eastern Zaohu faulted-nose belt developed lots of complex fracture structure, but the northern depression belt developed little faults. Weibei Sag developed six unconformity surfaces, among which N g/E s4 or N g/ E k l and lower E k2/E k3 are regional unconformity surfaces. For these reasons, different regions developed different pathway system in Weibei Sag. Based on the analysis of reservoirs in Weibei Sag and the characteristics of pathway system, we concluded the controlling of different passage system on hydrocarbon migration and accumulation. We find that sand body pathway system may control the forming of lithologic pinchout reservoirs and sand lens reservoirs, fault pathway system may control the forming of unconformity-fauh reservoirs, fault-block reservoirs and structural-lithologic reservoirs, fault-unconformity pathway system may control the forming of fault-block reservoirs, lithologic reservoirs and fault-lithologic reservoirs, and fault-unconformity-sand body pathway system may control the forming of lithologic pinchout reservoirs, unconformity reservoirs, fault-block reservoirs and fauh-lithologic reservoirs. The study result is favorable for reservoir exploration and prediction in Weibei Sag.