四川盆地北斜坡灯四段优质丘滩体储层识别及有利区预测

Identification and favorable area for exploration of hilly-shoal high-quality reservoir in the fourth member of Dengying Formation in the northern slope of Sichuan Basin

四川盆地北斜坡台缘带边缘灯影组四段(灯四段)源储配置关系优越,勘探潜力巨大。在沉积和溶蚀的双重作用下,研究区灯四段储层纵横向均表现出很强的非均质性,已钻井测试产量普遍较低。前人研究认为北斜坡优质储层的发育是控制灯四段气藏规模的关键因素,如何识别优质储层,成为灯四段丘滩体储层预测及目标优选的关键所在。针对传统储层地震识别预测存在明显的多解性问题,和测井数据和岩心能反映地层实际特征这一事实。从已钻井的成像测井资料出发,对比岩心孔洞发育特征,优选优质储层层段,标定合成记录和地震剖面,总结灯四段优质储层测井及地震响应特征,再通过正演模拟、古地貌分析、地震属性分析和储层预测等方法,建立研究区优质丘滩体储层识别模式,明确优质储层纵横向发育特征,精细刻画岩性圈闭及优质丘滩体储层平面展布特征,为北斜坡灯四段勘探开发提供技术支撑。研究表明:优质丘滩体储层主要发育在灯四上亚段中上部,厚度在10~60 m不等,横向上与古地貌耦合关系较好,主要分布在近台缘古地貌高部位。

The fourth member of the Dengying Formation(Deng 4 Member)at the edge of the platform margin of the northern slope of the Sichuan Basin has superior source-reservoir configuration and huge exploration po⁃tential.Under the dual effects of deposition and dissolution,the reservoirs of Deng 4 Member in the study area show strong heterogeneity in both vertical and horizontal directions,and the tested production of drilled wells is generally low.It is considered that the development of high-quality reservoirs in the northern slope area is the key factors to control the scale of Deng 4 Member gas reservoir.How to identify high-quality reservoirs has be⁃come the key to reservoir prediction and target optimization of Deng 4 Member.There are obvious multi-solu⁃tion problems in traditional reservoir seismic identification and prediction,while logging data and core are the true reflection of the formation.In this regard,based on the seismic and geological characteristics of the drilled wells,combined with the imaging logging data,this paper compares the development characteristics of core pores,optimizes the high-quality reservoir intervals,calibrates the synthetic records and seismic profiles,and summarizes the logging and seismic response characteristics of the high-quality reservoirs in Deng 4 Member,and then establishes the identification model of the high-quality reservoirs in the study area through forward mod⁃eling,paleogeomorphology analysis,seismic attribute analysis and reservoir prediction.The vertical and hori⁃zontal development characteristics of the high-quality reservoirs are clarified,and the lithologic traps and the plane distribution characteristics of the high-quality reservoirs are finely characterized,which provides technical support for the exploration and development of Deng 4 Menber in the northern slope area.The research shows that the high-quality hilly-shoal reservoirs are mainly developed in the middle and upper part of the upper submember of Deng 4 Member,with a thickness ranging from 10 to 60 m,and have a good coupling relationship with the paleogeomorphology in the horizontal direction,mainly distributed in the high part of the paleogeomor⁃phology near the platform margin.