柴达木盆地第四系倾斜式气藏的形成机理

Forming Mechanism of Gas Reservoirs with Inclined Gas-Water Interface of Quaternary in Qaidam Basin

柴达木盆地涩北1号气田的气水界面不是一个水平面,呈现向北东倾斜的斜面,气田东北翼的气水边界比西南翼低30余米。其形成机理是,来自西南方昆仑山的地层水流经涩北1号气田,并在东北方向露头区渗出,在独立的流体流动系统内形成的水动力压差,导致涩北1号气田的气水界面发生倾斜(约0.5°),气水界面与构造等值线不一致,称其为气水界面倾斜式气藏。这类气藏的研究对该区天然气勘探、含气面积、储量计算和开发井网部署等方面的研究都有密切的关系。

The gas-water interface of Sebei-1 gas field in Qaidam basin is not a horizontal plane, but an inclined ones, which slopes down to northeast. The interface of northeast wing is lower over 30 meters than that of the southwest. This paper thinks that it is caused by the hydrodynamics system. The formation water coming from Kunlun Mountain locating at southwest of the basin runs through Sebei-1 gas field, and discharges from the surface at northeast to the field. In the independent hydrodynamics system the difference of water pressure between the northeast and southwest wing brings about the inclined gas-water interface, which is inconsistent with structural contour. The study on gas reservoirs with inclined gas-water interface is very important in natural gas exploration, calculating gas reserves, and defining well position in Qaidam basin.