关键词: 成藏条件, 主控因素, 探勘方向, 北部山前带, 吐哈盆地

Abstract:

Petroleum exploration of Huanghua Depression is very concerned due to the discovery of Nanpu Oilfield. Based on the deep crust structure features, there are double lowvelocity layers in the mid-crust, with depth of 15 km and 20 km respectively. It is known that the lowvelocity layer ofmid-crust is rich in gases （such as CO₂, CO, H₂ etc.） which can synthesized into hydrocarbons under the moderate temperature and pressure conditions. The mantle fluid activities （such as alkaline metasomasis and Mg ²⁺ metasomasis） and the mantle source CO₂, CH4 and He gases （Gang 151 well） in the basin imply that they came from the deep hydrothermal fluids. Several buried hill structures developed in Huanghua Depression, such as Shenqingzhuang, Kongdian, Beidagang, Nandagang, Yangsanmu and so on. According to the inorganic genetic hypothesis, there are some large oil and gas reserves in the deep buried hills, rather than in the Tertiary sandstone lithologic reservoirs.

Key words: accumulation condition, controlling factors, exploration direction, north piedmont zone, Tuha Basin