准噶尔盆地侏罗系深层煤岩气地质特征与成藏模式
Geological characteristics and accumulation mode of the Jurassic deep coal-rock gas in Junggar Basin
摘要
准噶尔盆地侏罗系煤系地层发育,可作为良好的生储层系.于盆地白家海凸起钻探的CT1H井在侏罗系西山窑组煤岩储层获高产气流,打破了 2000m以深的传统煤层气勘探开发深度禁区,预示着深层煤岩气有望成为规模增储上产的新型天然气资源类型.基于准噶尔盆地侏罗系煤岩气勘探成果,结合铸体薄片、扫描电镜、核磁共振等实验方法对深层煤岩气地质特征、成藏模式展开系统研究,进一步明确煤岩气勘探方向.准噶尔盆地发育西山窑组②号和八道湾组⑤号两套主力煤岩,腹部地区西山窑组为低阶原生结构煤,煤岩储层孔隙度平均为17.25％,生气能力差,南缘西山窑组为中阶煤,储层孔隙连通性好,游离态煤岩气占比高;八道湾组为中阶原生结构煤,煤岩孔隙度平均为3.12％,吸附态煤岩气占比达89.75％.盆地内侏罗系深层煤岩气主要发育他源构造型、自源地层型和自源构造型3类成藏模式.结合地质条件及控藏要素进行综合分析认为,准噶尔盆地侏罗系深层煤岩气有利面积合计2385km2,预测煤岩气资源量为4260×108m3;盆腹区滴南—白家海地区西山窑组、八道湾组和南缘地区西山窑组是准噶尔盆地煤岩气重要的有利勘探方向.
Abstract
The Jurassic coal measures were well developed in Junggar Basin,which served as both good source rock and reservoir.A Well CT1H was drilled in Baijiahai Bulge,and high-yield gas flow was obtained in the Jurassic Xishanyao Formation coal rock reservoir,breaking through the traditional depth forbidden zone for CBM exploration and development at a depth greater than 2000 m,which indicated a new type of natural gas resource for increasing reserves and production on a large scale.Based on the exploration results of the Jurassic coal-rock gas in Junggar Basin,and combined with experimental methods such as casting thin section,scanning electron microscope,and nuclear magnetic resonance,a systematic study has been conducted on the geological characteristics and hydrocarbon accumulation pattern of deep coal-rock gas,and the future exploration orientation has been clarified.The study results show that two sets of main coal rocks,namely,coal rock No.2 in Xishanyao Formation and coal rock No.5 in Badaowan Formation,were developed in Junggar Basin.Xishanyao Formation coal rocks in the basin hinterland are characterized by low rank and primary structure,an average porosity of 17.25％,and poor gas generation capacity,while those in the southern basin margin are composed of medium-rank coal,with good connectivity of pores and a high proportion of free gas.Badaowan Formation coal rocks are characterized by medium rank and primary structure,with an average reservoir porosity of 3.12％and a proportion of adsorption gas of 89.75％.There are three main types of hydrocarbon accumulation patterns of the Jurassic deep coal-rock gas in the basin,i.e.,allogenetic structural type,authigenic stratigraphic type,and authigenic structural type.The comprehensive study of geological conditions and gas accumulation control factors indicates that the favorable exploration area of deep coal-rock gas is 2385 km2,and the predicted coal-rock gas resources are 4260×108m3 in Junggar Basin.The future exploration orientation of coal-rock gas includes Xishanyao Formation and Badaowan Formation in Dinan-Baijiahai area in the hinterland basin and Xishanyao Formation in the southern margin of the basin.
关键词
准噶尔盆地/侏罗系/煤岩气/地质特征/成藏模式/资源潜力/勘探方向Key words
Junggar Basin/Jurassic/coal-rock gas/geological characteristics/hydrocarbon accumulation pattern/resource potential/exploration orientation引用本文复制引用
出版年
2025
NETL
NSTL
万方数据