四川盆地仪陇地区飞仙关组鲕粒滩地震预测

Seismic prediction of oolitic beach of Feixianguan Formation in Yilong area,Sichuan Basin

四川盆地仪陇地区飞仙关组鲕粒滩型储层埋藏深度较大,沉积地质背景较为复杂,钻至深层的探井较少,难以准确预测鮞粒滩型储层的空间分布,制约了飞仙关组的油气勘探。飞仙关组储层主要为该组的一段、二段鲕粒滩,岩性以亮晶鲕粒灰岩和残余鲕粒灰岩为主,大多分布于台缘带上。地震正演模拟结果显示,鲕粒滩在地震剖面上外形呈现为透镜状,具有较强振幅和较低频率。采用地震沉积学研究方法,在鲕粒滩发育的台缘带上,利用地震振幅属性有效地预测仪陇—平昌地区飞仙关组鲕粒滩储层的空间展布。鲕粒滩型储层的识别及其分布特征与实际钻探结果匹配度较高,证明通过地震属性分析对鲕粒滩型储层的识别及分布进行预测是切实可行的,为下步对该类储层进行勘探打下了良好的基础。沉积相分析、地震正演模拟与地震属性分析有机结合能有效进行深层鲕粒滩储层识别与勘探。

The oolitic shoal reservoir of Feixianguan Formation has a large burial depth,and complicated sedimentary geological background in Yilong area.It is difficult to accurately predict the spatial distribution of oolitic shoal reservoir because there are few deep exploration wells,which restricts the oil and gas exploration of Feixianguan Formation.The Feixianguan Formation reservoir is mainly composed of the first and second sections of oolitic shoals,which are mostly distributed on the platform margin.The lithology is mainly composed of bright crystal oolitic limestone and residual oolitic limestone.According to the results of forward seismic modeling,the oolitic shoal is lenticular in shape,with strong amplitude&low frequency.The spatial distribution of oolitic shoal reservoir of Feixianguan Formation in Yilong Pingchang area can be effectively predicted by using seismic sedimentology and seismic amplitude attributes.The identification and distribution characteristics of oolitic beach reservoirs match well with the actual drilling results,which proves that it is feasible to predict the identification and distribution of oolitic beach reservoirs through seismic attribute analysis,and lays a good foundation for further exploration of this kind of reservoirs.The organic combination of sedimentary facies analysis,seismic forward modeling and seismic attribute analysis can effectively identify and explore deep oolitic beach reservoirs.