川东北地区茅口组储层地震响应特征及预测方法

川东北龙会场—龙门地区位于茅口组沉积高能相带及古地貌有利部位, 具备形成相控和岩溶储层的条件, 区内钻遇茅口组的井常见良好的油气显示, 具有较大的勘探潜力。但茅口组储层非均质性强, 厚度薄, 展布规律不清, 地震响应特征不明显, 导致一直未能形成行之有效的储层地震识别模式。针对以上问题, 综合利用地震和地质资料, 从储层单井特征研究出发, 结合正演模拟挖掘储层地震响应特征, 建立茅口组储层地震预测模式。重点分析了古地貌、高角度和低角度断层对储层发育的影响, 建立了川东北地区茅口组储层综合地震识别模式。研究认为, 高能沉积的颗粒滩相及岩溶古地貌是茅口组储层形成的关键因素, 低角度和高角度断层进一步改造储层, 高角度断层是沟通志留系和奥陶系烃源岩的纽带。因此, 有利相带、古地貌高部位以及高、低角度断层发育区为勘探的最有利区, 满足此识别模式的广大向斜区同样具有较大的勘探潜力。

The Maokou Formation in the Longhuichang-Longmen area, northeastern Sichuan, is located in the sedimentary high-energy facies belt and is a part of the paleogeomorphology, having favorable conditions to form facies-controlled karst reservoirs.Wells drilled in the Maokou Formation of the study area commonly show good oil and gas contents, indicating considerable exploration potential.However, the Maokou Formation has strong reservoir heterogeneity, low thickness, and unclear reservoir distribution patterns and seismic response characteristics.This has failed to form an effective reservoir seismic prediction model.Given these problems, this study summarized the seismic response of the reservoir and established an effective seismic prediction method for the Maokou Formation reservoir based on the seismic geological data, single-well characteristics of the Maokou Formation reservoir, and forward modeling.Based on the detailed geological background, single-well characteristics, and seismic prediction, the impact of paleogeomorphology and high-and low-angle faults on reservoir development were analyzed to establish a detailed seismic identification model for the Maokou Formation reservoirs in Northeast Sichuan.This study has shown that the shoal facies and karst paleogeomorphology of high-energy deposition are the basis for forming reservoirs in the Maokou Formation.Low-and high-angle faults can further expand and transform the reservoir, and high-angle faults are the links between the Maokou Formation and Silurian to Ordovician source rocks.Therefore, the favorable facies belt, the high part of the paleogeomorphology, and the high-low angle fault development area were the most favorable areas for exploration.A combination of seismic facies and attributes should be used for reservoir prediction under the constraints of the aforementioned geological information.Syncline areas that meet the prediction model also have considerable potential for exploration.