准噶尔盆地吉木萨尔凹陷芦草沟组致密储层裂缝特征和成因机制  

Research on the types and genetic mechanisms of tight reservoir in the Lucaogou Formation in Jimusar Sag,Junggar Basin

作　　者：张云钊 曾联波[1] 罗群[2] 张晨[1] 吴浩[1] 吕文雅[1] 代全齐 朱德宇 

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油大学(北京)非常规天然气研究院,北京102249

出　　处：《天然气地球科学》2018年第2期211-225,共15页Natural Gas Geoscience

基　　金："十三五"国家科技重大专项(编号:2016ZX05003001);国家重点基础研究发展计划(973)项目(编号:2015CB250901)

摘　　要：准噶尔盆地吉木萨尔凹陷芦草沟组储层致密,裂缝较为发育,但裂缝的类型和成因机制研究尚不明确。针对二叠系芦草沟组致密储层,利用野外露头观察、岩心观察、岩石薄片观察和测井识别等手段,进行裂缝特征描述、识别、成因的研究。吉木萨尔凹陷芦草沟组致密储层发育构造裂缝、成岩裂缝以及异常压力缝3种裂缝类型。依据裂缝切割关系、岩石声发射实验、碳氧同位素和锶同位素分析方法认为研究区二叠系致密储层发育4期构造裂缝,分别在印支期、燕山早期、燕山晚期和喜马拉雅早期构造作用下形成,其中第4期构造裂缝发育程度最高,充填程度最低,有效性最好。吉木萨尔地区芦草沟组储层发育的层理缝的形成与古构造应力、沉积成岩作用、生烃排酸溶蚀等作用相关,大多顺层理产生破裂,原油顺层理缝分布。通过对研究区层理缝研究分析,总结出构造—成岩和生烃排酸溶蚀2种层理缝成因。The reservoirs were commonly tight and fracture-developed in Lucaogou Formation of Jimusar Sag,however,the genetic mechanism of fracture was not clear.The character description,recognition,and cause of formation were researched in this paper aiming at the tight reservoirs in the Permian Lucaogou Formation by using field observation,core observation,cast section and logging recognition.The structural fractures,diagenetic fractures and abnormal pressure fractures were developed in the tight reservoirs of study formation,among them structural fractures included high-angle and medium-low angle fractures,abnormal fractures consist of drainage fractures,diagenetic fractures were mainly bedding fractures.Based on cutting relation,rock acoustic emission experiment,oxygen and strontium isotopes analysis,structural fractures within Permian sand reservoirs in study area were classified into 4 periods,of which the 4 th stage fractures were the most valid with highest development and lowest mineral filling degree.The formation of bedding fractures within Lucaogou Formation of Jimusar district was related to paleo-structural stress,sedimentation and diagenesis,and acid dissolution caused by hydrocarbon generation,most bedding fissure burst into fractures and oil distributed along the bedding fractures.Two bedding fractures formation modes were summarized based on bedding fractures study in study area：structural-diagenesis cause and hydrocarbon acid dissolution cause.

关 键 词：吉木萨尔凹陷 致密储层 裂缝 成因机制 

分 类 号：TE122.2[石油与天然气工程—油气勘探]