川西北剑阁地区上二叠统长兴组生物礁储层的地球物理特征及正演模拟

Seismic forward modeling on the reef reservoir of Upper Permian Changxing formation in Jian'ge area,northwest Sichuan Basin

川西北剑阁地区二叠系长兴组生物礁储层具有埋深大、非均质性强、气水关系复杂、地震反射多变和勘探难度大等特点。岩心观察结果表明,生物礁呈多期发育特征,优质储层多发育于晚期礁盖白云岩中。利用钻井及测录井等资料,建立精细地质模型,通过地震正演模拟,总结出剑阁地区长兴组生物礁及礁储层的地震响应特征,分析不同礁储层发育条件对地震响应的影响,从而建立了研究区生物礁及礁储层地震识别模式,认为储层厚度及储层纵向发育位置是影响生物礁地震反射模式的重要因素。采用地质-地震紧密结合的研究思路为四川盆地礁滩气藏地震勘探提供理论依据。

Reef reservoir of Upper Permian Changxing Formation of Jian＇ge Area, northwest Sichuan Basin is characterized by deep burial depth, strong heterogeneity, complicated gas-water distribution, variable seismic reflection and difficult explora- tion. Core observation shows that the reef development was of multi-phases and high-quality reservoirs always existed in the late reef cap dolomite. Based on well logging and drilling data,a refined geologic model is built and seismic response charac- teristics of reef and reef reservoir for the Changxing formation in Jian＇ge is summarized by seismic forward modeling. Thus, we have established the seismic identification mode for reef and reef reservoir after analyzing the impact of different reef res- ervoir development conditions on the seismic response in the study area. Finally, we conclude that reservoir thickness and res- ervoir vertical position are important factors on reef seismic reflection mode. The research idea of seismic and geology close combination provides theoretical foundations for seismic exploration of reef-shoal reservoirs in Siehuan Basin.