构造因素对油气的分布起着控制性的作用,断裂活动特征决定着一个盆地或凹陷油气的富集与分布.本文通过对北大港构造带东翼所有断裂的仔细研究,统计分析了区内20条规模较大断裂的断距在纵横向上的变化,结合20余条地震剖面和8条构造发育史剖面,综合分析认为北大港构造带东翼的断裂活动主要为:古近纪活动期和新构造期(0.78 Ma至今)活动期.而在新近纪,研究区内断裂(或构造)活动极其微弱,多数断裂没有活动.从演化过程、空间分布等方面认为:港东-唐家河构造带,晚期构造活动对先存构造的破坏性较弱,与白水头构造带的断裂活动具有一定的相似性,形成了典型的花状构造;而白东构造带在新构造期断裂活动强烈,有些新生断裂切割到了古近系地层,有的断裂已达地表附近,形成了"对倾式"的断裂组合.并初步讨论了断层活动对油气运聚的影响.%Structural factors play a controlling role in the distribution of oil and gas, and oil and gas enrichment and distribution in a basin or in a sag depend on characteristics of fault activities. The authors carefully studied all the fractures in eastern Beidagang tectonic belt, calculated and analyzed fracture distance variations of 20 large faults in vertical and horizontal directions in combination with over 20 seismic sections and 8 structural development profiles in the study area. On such a basis, the authors hold that the main fault activities in eastern Beidagang tectonic belt occurred in Paleocene tectonic period and Neocene tectonic period. In Neocene tectonic period, however, fault activities were extremely weak, and most faults were not active. From evolutionary process and spatial distribution, it is considered that the destructive effect of late tectonic activities on earlier faults was weak, and fault activities were somewhat similar to things of Baishuitou tectonic belt in Gangdong-Tangjiahe tectonic belt, forming a typical flower-shaped structure. Nevertheless, fault activities in Baidong tectonic belt were strong in Neocene tectonic period, and some new faults cut Paleocene strata with some reaching the near-surface place, forming “face toward sloping type” fault combination. The influence of fault activities on hydrocarbon migration and accumulation is also preliminarily discussed in this paper.
展开▼
