潜江凹陷周返断裂带岩性油藏成藏模式研究

在充分认识含油气盆地的基本石油地质条件的前提下,油气成藏的模式是寻找油气勘探切入点的关键。潜江凹陷周返断裂带大多数岩性油藏主要分布在周返地区与断层配置的构造斜坡带上。其中潜三、四段烃源岩厚度最大,生油指标高、成熟度好、生油潜力大,是主要的油源层段;三角洲前缘沉积体系为油气成藏提供了丰富的储集空间;蒸发岩类是潜江凹陷内最理想的区域性盖层;潜江组地层中有规律展布的断层发育带使得大面积分布的含油岩性在侧向经断层、构造的封挡形成多个有效的复合圈闭。周返断裂带主要形成2种岩性油藏:在单斜背景上砂体上倾尖灭,形成上倾尖灭岩性油气藏,或在断鼻或背斜构造背景上,河道砂体受断层切割形成断层 岩性油气藏或构造 岩性油气藏。

Research on the Accumulation Pattern of Lithologic Reservoir in Zhoufan Fault Zone of Qianjiang Depression

Through fully understanding the basic petroleum and geological conditions in the oilfield,it was considered that the accumulation models of reservoir was the key of oil and gas exploitation.Most of the lithologic reservoirs in Zhoufan fault zone of Qianjiang Depression were mainly distributed in Zhoufan zone and structural slope of fault.The thickest source rocks were developed in Qian 3 and Qian 4 sections with good maturity,great potential and favorable oil-generating indexes;the delta front provided a good reservoir space for oil and gas;evaporate sediments were the most ideal regional cap-rocks in Qianjiang depression;the development zone of fault with rule exhibition in Qianjiang formation made the large area of oil lithologic forming some effective composite traps by the fault and structure.Zhoufan fault zone mainly forms two kinds of lithologic reservoirs;one is through the background of monoclie formed lithologic reservoir with sand body upward pitchout,the other is through the background of fault nose and fault anticline,channel sand body incised by fault formed fault lithologic reservoir or structure lithologic reservoir.