普光地区长兴组生物礁储层分布预测

The prediction of reef reservoir distribution in Changxing Formation of Puguang area

川东北普光地区长兴组生物礁具备广阔的勘探潜力。文中对比了普光和元坝地区生物礁的生长模式,分析了生物礁及储层的地质特征,总结了礁相白云岩储层的纵横向分布规律。在此基础上,利用测井资料、地震资料,进行生物礁模型地震正演,确定生物礁及储层的地震相识别模式;采用古地貌分析确定储层发育的有利沉积相带,并通过沉积相带的展布和适宜的时窗选取规避不利岩性(泥灰岩)的干扰,再使用相面法、属性分析、波阻抗反演对有效储层进行精细预测,建立了一套适用于普光地区的生物礁储层地震预测方法,定量预测了普光地区长兴组生物礁储层的分布,认为生物礁储层垂向上主要发育于礁盖,横向上主要分布在台地边缘的狭窄条带上。预测结果与钻井资料、礁相储层分布规律相符,证明了方法的有效性。

There is a promising exploration potential in Changxing Formation of Puguang area,northeastern Sichuan Basin.In this paper,the authors made a comparison of the growth pattern of reef between Puguang area and Yuanba area,conducted an analysis of the geological features of reef and reservoir and drew a summary on vertical and horizontal distribution law of reef dolomite reservoir.On such a basis,a reef seismic forward model was established to obtain the identification mode of seismic facies using logging and seismic data.In order to avoid the interference from marly limestone,the authors predicted favorable sedimentary facies belt of reservoir growth using palaeogeomorphology analysis and picked an appropriate time window for reservoir prediction.Finally,the authors used seismic facies reading,attributive analysis and wave impedance inversion to accurately predict the effective reservoir distribution.So a seismic prediction method for reef reservoir in Puguang area was established and the reef reservoir distribution in Puguang area was predicted quantitatively.The prediction result indicates that the reservoirs mainly occur on the reef cap in vertical dimension and on a narrow belt along the platform margin in horizontal dimension.Meanwhile,the congruence between prediction result and well data confirms the effectiveness of the proposed method.