埕岛地区中生界储层特征及控制因素

MESOZOIC RESERVOIR IN CHENGDAO AREA AND ITS CONTROLLING FACTORS

中生界是埕岛地区下一步勘探的重要层系,而有利储层预测是制约勘探的关键。为了明确中生界储层发育的控制因素,综合利用岩心描述、薄片分析、测井解释、物性测试等资料,对储层类型及物性特征进行了分析,并通过与相关地质因素对比,揭示了有利储层发育的影响因素。结果发现,埕岛地区中生界主要发育碎屑岩和火成岩两类储层,储集空间以次生孔隙为主,储层物性在空间上的分布具有很强的非均质性;储层物性受岩性、不整合面、断裂及成岩作用的控制,岩性上含砾砂岩、砂岩、粉砂岩、砾岩、火成岩物性依次变差;不整合面对储层物性的影响距离大约为100m,纵向上100m范围内离不整合越近物性越好,横向上距主干断层越近物性越高;溶蚀、溶解性成岩作用是次生孔隙发育的重要原因。

The Mesozoic is the next exploration target in the Chengdao area.Effective reservoir prediction is the key to successful exploration.In order to reveal the controlling factors of the Mesozoic reservoir,reservoir types and their physical features are studied using cores and well logs.Results suggest that there are two kinds of reservoirs,say,clastic rock and volcanic rock.Secondary pores predominate.The distribution of reservoir physical parameters is heterogeneous and controlled by lithology,unconformity,faulting and diagenesis.Porosity and permeability are the major lithological parameters which decrease in an order of pebbly sandstone,sandstone,siltstone,conglomerate and volcanic rock.In terms of unconformity and fault,the influence is restricted in a distance of 100 m.For same reservoir lithology,the shorter the distance between the reservoir and unconformity and/or fault,the higher the porosity and permeability of the reservoir.Diagenesis plays important roles to the formation of secondary pores.