东营凹陷中央隆起带断裂构造及油气运移

Faulted structures and hydrocarbon migration in central uplift belt of Dongying Depression

东营凹陷中央隆起带的形成是在区域和局部构造应力场的控制下,由陈南断裂的伸展断弯褶皱和盐-泥塑性层拱张共同作用的结果。受盐-泥层分布、断层活动时的沉积特征、盆地区域构造应力场等因素的差异作用,中央隆起带构造的发育程度及组合特征在空间上有较显著的差异,可划分为辛镇、东营及梁家楼-现河庄3个构造带。中央隆起带上,油气分布与断裂活动关系密切:①断层活动强度由弱变强,油气主要分布于浅层,形成次生油藏;②断层的活动强度由强变弱,油气主要分布于下部,多为原生油藏;③断层的活动强度由弱变强又变弱,油气在上下层位均有分布,形成具多套含油层系。

Central uplift belt of Dongying depression has been formed as a result of joint action of the extensional fault-flexure folding of Chennan fault and diapirism of plastic salt-mud layers controlled by regional and local structural stress fields. Development levels and combination features of structures in the central uplift belt are spatially quite different, due to differential actions of various factors, such as distribution of salt-mud layers, sedimentary features when the faults were active and regional tectonic stress field. The central uplift belt can be divided into 3 structural zones, i.e. Xinzhen, Dongying and Liangjialou-Xianhezhuang structural zones. Distributions of oil and gas are closely related to faulting in the central uplift belt: (1) hydrocarbons have mainly been accumulated in shallow reservoirs as secondary pools when the strength of faulting changed from weak to strong; (2) hydrocarbons have mainly been accumulated in deep reservoirs as primary pools when the strength of faulting changed from strong to weak; (3) hydrocarbons have been accumulated both in shallow and deep reservoirs constitute complex oil-gas accumulation zone with multiple oil-bearing series and various types of oil pools when the strength of faulting changed first from weak to strong and then from strong to weak.