渭河盆地前新生界分布的物探特征及油气成藏条件分析

Analysis of distribution of geophysical characteristics and reservior-forming conditions in the pre-cenozoic strata in the weihe basin

渭河盆地是新生代断陷盆地,由地质露头剖面及钻井揭示,盆地基底为太古界及元古界深变质岩系;沉积盖层以新生界为主,局部钻遇古生界地层,沉积岩最厚超过7000 m.以往油气勘探程度较低,以新生界新近系和古近系为目的层,但未获重大发现;对古生界分布及油气成藏条件的研究尤为薄弱,因而制约了渭河盆地的油气勘探.依据区域重力、航磁资料,结合近年完成的电法及地震勘探成果,划分出盆地内前新生界分布区域,初步确定在宝鸡—咸阳断裂以北地区存在古生界,并提出盆地北部斜坡地区古生界的油气成藏模式,以利于今后的油气勘探.

The Weihe basin is a cenozoic fault basin. As revealed by field outcrop section and drilling, the basin has a metamorphic rocks basement of Archean and Proterozoic,mostly covered with Cenozoic,and locally Paleazoic with the largest thinkness of 7000 m. Due to the low degree of prospecting past time, the target is mainly of Neogene and Paleogene, but up to now , no significant discoveries have been made, and the research on distribution of Paleozoic and reservoir forming conditions is especially weak , thus restricted the oil and gas exploration of the basin. Based on the study of the data of regional gravity and aeromagneic survey, as well as the electricity and seismic prospecting, the pre-Cenozoic distribution area of the basin is divided, and it is confirmed that Paleozoic system exists in north of the Baoji-Xianyang fault, and the pattern of oil and gas reservoir-forming is brought forward, which is favorable for future＇s oil and gas exploration.