基于地震响应分析的相控反演技术在生物礁滩储层预测中的应用

Facies-controlled inversion technology based on seismic response analysis for predicting bio-reef shoal reservoirs

川东五百梯地区长兴组生物礁滩储层受开江—梁平海槽沉积相带控制,具有岩性物性复杂、非均质性强的特点,是制约该区高效勘探开发的主要因素。针对五百梯地区井位分布不均匀、相控明显的问题,依据地质认识结合地震特征刻画地震有利相带,随后通过地震相带进行相控插值建模,最后开展储层预测,该方法有别于传统插值方式,更符合地质规律。其技术思路为:首先,通过地震反射特征分析以及钻井资料,明确礁滩发育的地震反射模式;随后,利用生物礁滩发育模式及井资料优选敏感属性并刻画出礁滩发育有利相带;最后,利用相带刻画结果作为相控约束条件构建低频模型并采用分频反演方法进行储层预测。由基于相控分频反演的储层预测结果可知,储层主要发育在台缘礁相带、二排礁相带以及礁后滩相带,对应为古地貌较高位置,符合地质规律,为五百梯地区长兴组气藏高效开发奠定良好基础。

The Changxing Formation bio-reef shoal reservoir in the Wubaiti area of eastern Sichuan is controlled by the Kaijiang-Liangping Trough sedimentary facies belt.It possesses the characteristics of complex lithology and physical properties and strong heterogeneity,which are the main constraints for efficient exploration and development in this area.Focusing on the uneven distribution of well positions and substantial phase control in this area,this study described favorable seismic facies zones based on geological knowledge and seismic characteristics,then conducted facies-controlled interpolation modeling through seismic facies zones,and finally carried out reservoir prediction.This method was different from the traditional interpolation method and was more in line with geological laws.The technical idea was as follows:first,the seismic reflection pattern for the reef-shoal development was clarified by analyzing the seismic reflection characteristics and drilling data;then,the reef-shoal development pattern and well data were used to optimize the sensitive attributes and describe the favorable zone.Finally,the facies result was used as the control to construct a low-frequency model and predict the reservoir with the frequency-division inversion method.According to the results,based on facies-controlled frequency division inversion,the reservoirs have mainly been developed in the platform margin reef zone,the second reef zone,and the back reef shoal zone.The zones correspond to the higher position of the paleogeomorphology,which conforms to the geological laws and lays a good foundation for efficiently developing Changxing Formation gas reservoirs in the Wubaiti area.