源断裂在油气成藏与分布中的作用研究——以贝尔凹陷布达特群潜山为例

Influence of source faults of Budate group In Beier depression on hydrocarbon accumulation and distribution

大庆石油学院, 黑龙江 大庆 163318

Daqing Petroleum Institute,Daqing 163318,China

通过地震资料对贝尔凹陷布达特群源断裂发育及其活动特征进行了分析,发现贝尔凹陷布达特群发育有大量北东东和北北东向的源断裂。这些源断裂主要分布在凹陷的中部和东部地区,尤其是凹陷的中部源断裂更为发育。利用最大主应力方向与源断裂走向之间夹角大小,对贝尔凹陷布达特群源断裂在主要成藏期——伊敏组沉积末期的垂向封闭与开启性进行了研究,得到了贝尔凹陷布达特群源断裂在凹陷中部垂向封闭性差,开启程度高,是南屯组源岩生成排出油气向布达特群运移的主要输导通道这一认识。源断裂控制着贝尔凹陷布达特群油气成藏与分布,主要表现在①距源断裂越近油气富集程度越高及②断距越小的源断裂附近油气产量越高2个方面。

By analyzing the development characteristics of Budate group source faults in Beier depression based on seismic data, a lot of source faults are found. The directions of these faults are mainly northeast to the east and northeast to the north and the faults distribute in the central and east areas of the depression, especially in the central area. Using the angle between orientation of maximum principal compressive stress and strike of source-faults, the vertical seal and open features of source-faults in the end of Yimin stage sedimentary period (the main oil-gas accumulation period) are studied, showing that the source faults in the central area are poorly sealed and well opened in vertical direction and are the main migration pathway of oil-gas generating and expelling from the source-rock of Nantun formation. The source faults control oil-gas accumulation and distribution in the research area: 1) the nearer to the source faults is, the higher the oil-gas accumulation degree is; 2) the smaller fault displacement of the source fault is, the higher oil/gas output near the source fault is.