塔里木盆地轮古潜山暗河发育特征及其与油气富集的关系

Development characteristics of underground river and its relationship with oil and gas accumulation in Lungu buried-hill, Tarim Basin

综合地震及钻井、录井、测井、生产动态等资料,对塔里木盆地轮古奥陶系潜山的暗河进行了精细刻画,共识别出暗河174条,暗河面积达70.37 km2,并阐明了轮古潜山暗河明显受断裂控制的发育规律。同时,将暗河系统分为暗河主河道、暗河分支河道和暗河洞顶缝,并根据洞道规模大小及充填程度,进一步将暗河主河道分为洞大沟深区、廊道区和淤塞区;根据分支河道汇入主河道的垂向角度大小,将暗河分支河道分为垂降型、斜坡型和平缓型。统计分析及钻探实践表明:暗河主河道的洞大沟深区、分支河道的垂降型和斜坡型,以及暗河洞顶缝是最有利的岩溶储层发育区,也是油气富集的有利场所。

Based on the data of seismic,drilling,logging and production performance,underground river in Lungu Ordovician buried-hill of Tarim Basin are described in detail,and 174 rivers are identified,and the river area is up to 70.37km^2.It is also expounded that the development of the underground rivers are obviously controlled by faults.At the same time,the underground river system is divided into main channel,branch channel and cave roof fissure.According to the size and filling degree of the tunnel,the main channel is further divided into deep zone of the big ditch,corridor zone and silting zone.The branch channel is further divided into vertical type,slope type and flat type according to the vertical angle of the branch channel entering the main channel.Statistical analysis and drilling practice showed that the deep zone of the big ditch of the main channel,the vertical and slope types of the branch channel,and the cave roof fissure of the underground river are the most favorable development area of karst reservoir and the favorable play for oil and gas accumulation.