徐家围子断陷兴城地区天然气气藏特征分析

Characteristics Analysis of Natural Gas Reservoir in Xingcheng Region in Xujiaweizi Fault Depression

松辽盆地北部徐家围子断陷天然气藏形成机制和分布规律复杂,制约了天然气勘探开发工作的进展。为此,依据兴城地区营城组天然气气藏的成藏特征分析,研究了该地区深层气藏类型和成藏模式。营城组主要分为上部的砂砾岩气藏和下部的火山岩气藏。分析认为徐家围子断陷徐东地区营城组四段砾岩气藏为岩性气藏,火山岩气藏类型为岩性—构造气藏。营城组火山岩气藏流体分布具有明显的上气、下水的特点,没有统一的气水界面。砂砾岩与火山岩纵向叠置,成藏模式为下生上储式。

The subtle gas reservoirs in Xujiaweizi fault depression of the Songliao Basin are characterized by complex genetic mecha- nisms and distribution patterns, challenging gas exploration and de- velopment. For this reason, according to the analyses of natural gas reservoir forming characteristics of Yingcheng formation in Xingcheng, the paper studied the gas reservoir type and pooling pattern in the area. Yingcheng formation contains upper sandy con- glomerate reservoir and lower volcanic reservoir. The analysis showed that the gas reservoir of Yingsiduan formation 4th section in Xujiaweizi fault depression is regarded as lithologic type, and volcanic rock gas reservoir is lithologic - structure type. The fluid distribution of gas reservoir of Yingsiduan formation volcanic rock has apparent characteristic of upper gas and lower water without unified gas-water interface. The sandy conglomerate superimpose on volcanic rock in longitudinal direction, so that the pooling pat- tern is lower source rocks and upper gas reservoirs.