蚂蚁体参数敏感性分析及足201井区龙马溪组页岩储层裂缝预测研究

Sensitivity Analysis of Ant-Tracked Parameters and Fracture Prediction in the Longmaxi Formation Shale Reservoir of Zu 201 Block

摘要: 天然裂缝是影响页岩气产能的关键因素之一，四川盆地五峰组–龙马溪组优质页岩是中国南方海相页岩气开发的主力产层，前人对该地区页岩储层裂缝研究较少。本文以四川盆地足201井区龙马溪组页岩储层为研究对象，分析了初始蚂蚁边界、蚂蚁追踪背离、蚂蚁搜索步长、非法步长、合法步长及终止条件等六个关键参数对裂缝提取结果的影响规律，明确了各参数对蚂蚁体稀疏性或密集性的控制作用。结合实际地震属性与地质特征，优化参数并进行方向约束与产状过滤，结果表明足201龙马溪组南部较北部裂缝发育程度明显偏高、东部较西部裂缝发育程度明显偏高。经验证，蚂蚁追踪结果与电成像测井解释的裂缝走向高度一致，表明该方法在复杂构造区页岩储层裂缝识别中具有较高的可靠性和实用性，为该类地区的裂缝建模与油气开发提供了有效技术支撑。

Abstract: Natural fractures are one of the key factors affecting shale gas productivity. The high-quality shale in the Wufeng-Longmaxi Formations in the Sichuan Basin is the main producing layer for marine shale gas development in southern China. Previous studies on fractures in the shale reservoirs of this region have been relatively limited. This paper focuses on the shale reservoir of the Longmaxi Formation in the Zu 201 Block of the Sichuan Basin. It analyzes the influence of six key parameters—Initial Ant Boundary, Ant Tracking Deviation, Ant Step Length, Illegal Step Length, Legal Step Length, and Stopping Criteria—on fracture extraction results, and clarifies the control effect of each parameter on the sparsity or density of the ant-tracked attribute volume. By integrating seismic attributes and geological characteristics, parameters were optimized with directional and geometric constraints. The results indicate that the fracture development degree in the southern part of the Longmaxi Formation in Zu 201 Well Block is significantly higher than that in the northern part, and the eastern part exhibits notably higher fracture density compared to the western part. Verification through electrical imaging log interpretation shows a high consistency with the fracture orientations predicted by ant tracking, demonstrating the reliability and practical utility of this method for fracture identification in complex structural shale reservoirs. This study provides effective technical support for fracture modeling and hydrocarbon development in similar areas.