焉耆盆地博湖坳陷含油气系统及勘探方向

OIL- AND GAS-BEARING SYSTEM AND ITS EXPLORATION TARGETS IN BOHU DEPRESSION OF YANQI BASIN

运用含油气系统的研究方法明确了焉耆盆地勘探思路 ,指出焉耆盆地博湖坳陷可划分出北部凹陷及南部凹陷两个含油气系统 ,二者形成的关键时刻均出现在新生代 ,与侏罗系煤系烃源岩二次生烃密切相关。北部凹陷含油气系统各地质要素和作用的匹配优于南部凹陷含油气系统 ;目前发现的油气藏均为与小型断裂有关的复式油气藏。由于较大型断裂对油气保存不利 ,且含油气系统油气就近运移 ,油气藏集中于生油窗内及其边缘 ,所以下一步的勘探应注意含油气系统生油窗边界地区的岩性圈闭和与小型断裂有关的复式圈闭。

By use of many methods of studying on oil and gas bearing system, it is pointed out, with a clear idea on Yanqi Basin, that Bohu depression there can be divided into northern and southern sags of oil and gas bearing system . The crucial time of both two sags were in Cenozoic, which has close correlation with secondary hydrocarbon generation of coal source rock in Jurassic. The rela tionships between various geologic factors and actions of northern sags are bett e r than those of southern sag. The discovered oil and gas reservoirs at present a re all complex ones concerned with small scale faults. Larger scale faults are not ideal for keeping oil or gas; and oil or gas often migrates to the close are a , so reservoirs are concentrated in oil generating window and its edges. The ne xt step on exploration should be paid more attention to lithologic traps around the oil generating window of oil and gas bearing system and those complex traps with small scale faults.