塔里木盆地塔河油田不同岩溶塌陷类型地震响应特征与识别

Seismic response characteristics and identification of different types of karst collapse in Tahe Oilfield,Tarim Basin

塔里木盆地塔河油田奥陶系碳酸盐岩储集层类型复杂多样。作为一种重要的油气储集体,岩溶塌陷是该区勘探开发的最重要目标之一。根据地震资料和实际钻井资料,将该区的岩溶塌陷分为负载型塌陷、构造型塌陷和落水洞型塌陷3种类型,依据实际参数对之进行了模型正演。正演结果表明:岩溶塌陷体在地震上反映为上部有同相轴"下凹"、内部强"串珠"状反射和杂乱反射;不同类型塌陷具有不同特征,构造型塌陷上部同相轴"错断"明显,落水洞型塌陷上部同相轴呈现出"漏斗状"特征。岩溶塌陷体正演模拟特征与实际地震反射特征吻合较好,证明设计的3种塌陷模型较为可靠。据此,可以在该区的地震剖面上识别出相应的岩溶塌陷模式。

Carbonate reservoirs of Ordovician are complex and diverse in Tahe Oilfield,Tarim Basin.As an important oil and gas reservoir,karst collapse is one of the most important targets of exploration and development in the area.Seismic and drilling data suggest that the karst collapse in this area can be divided into three types：load collapse,structural collapse and sinkhole collapse.Seismic modeling results show that the karst collapse body is characterized by the upper＂concave downward＂of seismic events,and the internal strong＂beaded＂and/or chaotic reflection,respectively.Different collapse types have different characteristics as the structural collapse shows the upper seismic events＂faulted＂features and sinkhole collapse in the upper reflection events shows the characteristics of＂funnel-shaped＂.Seismic modeling results of karst collapses coincide well with the actual seismic data,indicating that the three collapse models are reliable.And therefore,the karst collapse mode can be identified on the real seismic profiles in the area.