鲁北新生代隐伏火山岩及其石油地质意义

鲁北新生代隐伏火山岩可划分为3个喷发期6个亚期,9种火山岩岩石类型和同期侵入的辉绿岩。它们形成在近大陆边缘的板内裂谷型盆地,对于富有机质生油岩的沉积、各种储集体的形成、多种含油圈闭类型的形成以及有机质成熟向烃类转化都是非常有利的。作为储集岩主要有玄武安山岩、辉绿岩和湖底玄武质凝灰岩。储油空间主要为次生孔隙和裂缝。火山岩及其有关岩石在本区不仅形成了特殊的油气藏,而且还可作为盖层、封堵层、披复构造的基岩,因此对石油地质勘探有重要意义。

THE CENOZOIC BLIND VOLCANICS OF THE NORTHERN SHANDONG PROVINCE AND ITS PETROLIUM GEOLOGICAL SIGNIFICANCE

The outcrop areas of the volcanics are in two basins: Chanwei and Dezhou basins, and three fault-rifted zones: Binxian, Wudi, Yinan, and near the Wu-3 well of Chengzhikou. The volcanic eruption here are divided into three stages and six substages, i.e. the Tertiary stage includig 3 substages of the early-mid, mid-later and late Eocene, the Neogene stage and the Quaternary stage. Lithologically, the volcanics have basalt, andesite, quartz tholeiite, olivine tholeiite, olivine basalt, alkaliolivine basalt, picrite-porphyrite and sublake pyroclastics(i, e. basaltic tuff and basaltandesitic volcanic breccia). The first stage is talc-alkaline, with quartz tholeiite. The 2nd one is alkaline, with olivine tholeiite etc., partly containing nepheline. The 3rd stage is super-alkaline basanite, with nepheline and lencite. Geotectonically, our working area belongs to rift basins near continental margin. This condition are favourable for the deposition of source rocks rich in organism, the formation of different types of reservoirs, oil-bearing traps and the long-period stablity of heat flow, which are great help in the maturated transformation of organism. The volcanics and its related diabase may bring about nice secondary pores themselves, a fracture reservoir, which is an important oil-deposit. Moreover, volcanics sometimes can play a role as cap or seal of rocks and base of trapping structures. Therefore, the study on volcanics not only has a theoretical significance about tectonic movement and magmatic activity, but also possesses an actually important value in the petroleum geological exploration.