Abstract:

This paper analyzes the gas reservoir formation rules in Xujiaweizi deep volcanics, northern Songliao basin, studies four controls of gas reservoir formation, including gas generation intensity, big faults, structural traps and highly-porose acid volcanics. Based on drilling and geological data, this paper studies the formation, reservoir, and caprock of gas reservoir in deep volcanics in Gulong rift basin, uses gravity-magnetic anomalies which are highlighted through processing the weak gravity magnetic data to interpret the fault and volcanic lithology, and uses 2D seismic data to interpret the structure, based on these, structural traps are marked and their hydrocarbon potentials are forecasted in favorable areas according to sedimentary thickness. Based on a synthetic evaluation of favorable hydrocarbon areas, fault zone, structural traps and volcanics, this paper presents a favorable exploration target area where lies inside favorable hydrocarbon area, along faults, within structural traps and developed volcanic caprocks.

Key words: Gulong rift basin, volcanics, gravity-magnetic method, evaluation on exploration

摘要：

本文剖析了松辽北部徐家围子深层火山气藏成藏规律，总结出生气强度、深大断裂、构造圈闭和高孔酸性火山岩储层等4条火山岩气藏的主控因素。利用古龙断陷钻井和地质分析资料，对古龙断陷深层火山岩气藏生、储、盖进行了研究。对重磁资料进行弱信息增强处理，突出断陷地层的重磁异常，对断裂和火山岩岩性进行解释；利用二维地震进行构造解释，通过趋势消除法突出局部构造圈闭，并利用断陷期地层厚度对该区有利生烃范围进行预测。类比徐家围子气藏主控因素，联合有利生烃范围、断裂发育带、局部构造高和有利火山岩发育区对古龙断陷火山岩气藏进行综合评价，指出在断陷中部有利生烃范围内，沿断裂周围的局部构造高部位和火山岩储层发育区为有利勘探区域。

关键词: 古龙断陷, 火山岩, 重磁方法, 勘探评价