塔里木盆地巴麦地区石炭系低速异常碳酸盐岩的解释  

Interpretation of Carboniferous Low Velocity Anomalous Carbonate in the Ba-Mai Area,Tarim Basin

作　　者：郭倩[1] 蒲仁海[1] 

机构地区：[1]国家大陆动力学重点实验室/西北大学地质学系,西安710069

出　　处：《吉林大学学报（地球科学版）》2011年第3期689-696,共8页Journal of Jilin University：Earth Science Edition

基　　金：国家重大专项项目(2008ZX05001-003);中国石油化工股份有限公司海相前瞻项目(YPH08114)

摘　　要：巴麦地区即塔西南巴楚隆起-麦盖提斜坡,具有台地边缘-斜坡的古构造和古地理背景,这种台地边缘和典型的浅滩沉积暗示了该区具有发育生物礁的环境特征。区内先巴扎（XBZ）600 km2三维地震探区石炭系发育了巴楚组（C1b）生屑灰岩及标准灰岩、小海子组（C2x）3套灰岩,其中小海子组发现特殊响应碳酸盐岩,主要表现为厚度增大、频率增高、多出一条波峰同相轴的地震响应特征。通过差异厚度法、底面拉平法、地震属性法、正反演模型法,结合野外露头、岩心、镜下观察、录井、沉积相等综合分析,可初步推测该低速异常体为厚度增加、孔隙度增大的近东西向台地边缘障壁礁所致。礁体东西走向延伸超过25km,礁核区小海子组灰岩最厚62 m,礁外的小海子组50 m。台缘斜坡南倾,坡度陡,水平宽度1~2 km。礁后生屑滩北倾,坡度缓,水平宽度3~6 km。受色力布亚断裂带遮挡,该生物礁储层可以形成有利圈闭,面积约为42 km2,厚约45 m。Ba-Mai area stands for the Bachu uplift and Mageti slope in SW Tarim basin,it has a paleo-tectonic and paleo-geographic background of platform margin-slope,which implies a typical reef-bank environment characteristics.There are three layers of limestone developed in the XBZ 3D seismic working area,C1b biological clastic limestone,standard limestone and C2x limestone,in which a special seismic response carbonate was found,the main response characteristics are thickness and frequency increasing with an extra peak event.It can be indicated that the low velocity abnormal body was caused by a near EW platform margin barrier reef through different thickness,subface flatten,seismic attribute and forward and inversion methods,combined with analysis of field outcrops,core,microscopic observation,logging and sedimentary facies.The reef extends more than 25 km in EW,the maximum thickness of reef core area of C2x limestone is 62 m,outside thickness is 50 m.Platform margin slope trends to south,which has a 1-2 km horizontal width.Biological clastic bank behind the reef trends to north,the horizontal width is 3-6 km.Blocked by Selibuya fault,reefs traps can be formed,reefs area is about 42 km2 and about 45 m thick.

关 键 词：低速异常体 碳酸盐岩 小海子组 石炭系 巴麦(巴楚隆起-麦盖提斜坡) 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]