西湖凹陷中南部H构造断裂发育特征及控藏作用

Development characteristics and reservoir control of H structural faults in the central and southern parts of Xihu Depression

H构造位于西湖凹陷中央洼陷构造带中南部,紧邻富生烃的绍兴36洼且受多条断裂所分割的构造圈闭,具备良好的油气成藏条件,但目前该构造的断裂研究较为薄弱,制约了油气挖潜工作。为厘清断裂的发育特征及对油气成藏的控制作用,本文从三维地震解释及已钻井资料出发,通过分析H构造断裂发育特征及演化过程,开展断裂对构造内油气成藏的控制作用的研究,并划分油气成藏类型。研究表明:H构造内的断裂主要发育于古近纪,平面走向为NNE,断裂可分为通源断层及调节断层两个类别;其中位于构造东西两侧的F1及F4断裂控制构造的形成,断裂活动控制了古高点,断裂级别及断砂耦合程度可控制油气丰度。综合断裂活动性及源—断组合类型及油气输导特征等成藏要素,建立了2种油气成藏组合类型,为该构造下一步油气勘探提供指导。

The H structure is located in the central and southern part of the Xihu Depression central depression structural belt,adjacent to the hydrocarbon-rich Shaoxing 36 depression and divided by multiple faults as a structural trap,which has good conditions for hydrocarbon accumulation.However,currently,the research on faults in this structure is relatively weak,which restricts the exploration of hydrocarbon potential.To clarify the development characteristics of faults and their control over hydrocarbon accumulation,this article starts from 3D seismic data interpretation and drilling data,analyzes the development characteristics and evolution process of H structural faults,conducts research on the control of faults on hydrocarbon accumulation within the structure,and divides hydrocarbon accumulation types.Research shows that the faults within the H structure mainly developed in the Paleogene,the dominant trend was NNE.The faults can be divided into two hierarchical class:source rocks-linking faults and regulative faults.Among them,F1 and F4 faults located on the east and west sides of the structure control the formation of the structure,and fault activity controls the ancient high point.The fault level and fault sand coupling degree can control the abundance of hydrocarbon.Based on the comprehensive analysis of fault activity,source-fault combination types,and transportation models,two hydrocarbon accumulation models were established,providing guidance for the next step of oil and gas exploration in this structure.