松辽盆地深层火山岩天然气勘探方向

Exploration scheme of gas in deep-seated volcanic rocks in Songliao Basin

松辽盆地徐家围子断陷深层勘探程度最高,根据其主力烃源岩生气强度与断陷期地层厚度形态上的相似性,利用航磁异常与断陷期地层厚度叠合的方法,可在其他勘探程度较低的断陷中快速优选火山岩储集层发育并与烃源岩相匹配的深层断陷。结合地质资料以及钻井资料预测,松辽盆地火山岩天然气勘探有利的断陷是长岭断陷以及古龙断陷;根据近烃源岩或沟通烃源岩的航磁异常梯度带附近是火山岩天然气的富集区带这一重要认识,预测了长岭断陷及古龙断陷火山岩天然气勘探富集区带;对风险勘探井进行了评价,推荐钻探长岭断陷的长深1井,并认为古龙断陷古深1井北约6km处火山岩构造更为有利。提出全盆地需要针对火山岩储集层进行1∶50 000高分辨率航磁勘探的建议。

Based on the similarity between the hydrocarbon generation intensity of source rocks and the formation thickness of faulted depression in the Xujiaweizi faulted depression in Songliao Basin, an exploration scheme of superposition of magnetic anomaly on thickness of source rocks to choose matched faulted depressions and prospective volcanic rock formations in other depressions with less study degree is proposed. With the geological and logging data, Changling and Gulong Depressions are believed to be the most prospective gas reservoirs in volcanic rocks in Songliao Basin. According to the viewpoint that the vicinities of magnetic gradient belts close or connected to source rocks are the most promising areas for gas exploration, some prospective volcanic rock belts are predicted in the Changling and Gulong Depressions. From the preliminary evaluation of the wildcat wells, Changshen 1 in Changling Depression is recommended to drill. A volcanic structure, 6 km north to Gushen 1 in Gulong Depression, is believed to be more favorable to drill. With the purpose of exploring gas in volcanic rocks, a 1：50 000 high-resolution aeromagnetic survey to cover the entire basin is suggested.