准北缘哈山地区斜坡带网毯式油气成藏规律

综合利用露头、钻井、岩心和地震资料,对断层、不整合、砂体的输导能力进行评价,认为南部乌夏断裂带大断裂及其伴生断裂是研究区的油源断裂,为油气由深部向浅部垂向运移提供了重要通道;八道湾组和清水河组砂岩厚度大,泥质隔层少,横向连通性好,成岩作用弱,物性好,为油气横向运移的通道;不整合面上部的近物源底砾岩,分选差、物性差,对油气的横向输导作用不大.深浅2套断裂、上下2套毯状砂层匹配构成了研究区高效的网毯式输导格架.综合分析构造背景、输导体系、储层岩性-物性与含油性关系,提出了"断-毯-梁"三因素控藏的认识.断裂(油源断层、油藏断层)控制油气聚集层位,毯状输导砂体控制平面分布,鼻状构造背景控制相对聚集,储集层岩性、物性控制富集程度.成藏体系分析,建立了宽缓斜坡带源外沿梁网毯式输导成藏模式,指出毯内断层遮挡的断块圈闭、砂体上倾尖灭岩性圈闭、地层超覆圈闭和次级断裂沟通的毯上砂体构造-岩性圈闭、岩性圈闭为最有利的勘探目标.

Study on meshwork-carpet hydrocarbon pool-forming features in Hashan area,the sloping zone,the northern border of Junggar Basin

The hydrocarbon transporting ability of faults,unconformity and sandstone in the studied area was evaluated according to the comprehensive analysis of outcrop,drilling,core and seismic data.It is held that major fault and its accompanying faults in Wuxia fault belt are the oil-source faults,which are the vertical migration passage of hydrocarbon from bottom to top.The sandstones of Badaowan Formation and the Qingshuihe Formation are characterized by great thickness,less shale interlayers,good lateral connectivity,weak diagenesis and good physical properties,and they are the lateral migration passage of hydrocarbon.The basal conglomerate above the unconformity does not play a significant role in the lateral migration of hydrocarbon because of bad sorting and physical property.Two sets of deep and shallow faults and two sets of up and down sandbodies are composed of the effective meshwork-carpet passage system of hydrocarbon migration.According to the comprehensive analysis of tectonic setting,hydrocarbon migration system,reservoir lithology,property and oiliness,it is held that the faults(oil source faults,adjusted faults) control the horizon of hydrocarbon accumulation,blanket sandbodies control the plane distribution of hydrocarbon,nose structure controls the relative accumulation,and reservoir lithology and property control the enrichment degree of hydrocarbon.A meshwork-carpet hydrocarbon migration and accumulation mode through nose structure in the wide-gentle slope zone is set up based on the analysis of hydrocarbon accumulation system.It is pointed that fault block trap,pinch-out updip sandstone trap,stratigraphic overlap trap,the tectonic-lithologic trap and lithologic trap are favorable hydrocarbon exploration objectives.