Bright spot seismic reflections in carbonate strata are often correlated with effective reservoirs. Widely distributed bright spot reflections have been found in the Permian Changhsing Formation in the Longgang area, Northeast Sichuan Basin, China. However, there is still a lack of systematic understanding of the types, distribution, and geological origin of these bright spot reflections in the Longgang area. Integrated subsurface analysis has revealed that bright sport characteristics represent a combination of strong troughs and peaks, with thicknesses up to 30 ms of two-way time and have a shape like “a string of pearls” in the seismic section. The bright spots located in the platform margin show a NW-trending intermittent strip-like distribution, while in the open platform they are scattered. Bright spots are mainly distributed at the top of the Changhsing Formation and form in the platform margin and open platform environments. The distribution of bright spots has a good coupling with reefs and shoals located in the high paleogeographic regions of the Upper Changhsing Formation. The integrated analysis based on cores, thin sections, and geophysical data reveals that the “pearl-like” bright spots are indicators of needle-like dissolution pores, small karst caves, fracture–vug cystic caves and piebald karst fracture cave systems resulting from eogenetic karstification. Large-scale regression of sea level, which occurred at the end-Permian section, is the main control for reefs and shoals located in the exposed paleohighs suffering from eogenetic karstification. Exploration based on the location of bright spot seismic reflections may be a favorable target for hydrocarbons.

中文翻译：

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川东北龙岗地区长兴组二叠系碳酸盐岩矿床地震亮点特征及地质特征

碳酸盐岩地层中的亮点地震反射通常与有效储层相关。在四川盆地东北部龙岗地区的二叠系长兴组中发现了广泛分布的亮点反射。然而，目前对龙岗地区这些亮点反射的类型、分布和地质成因还缺乏系统的认识。综合地下分析表明，明亮的运动特征代表了强烈的波谷和波峰的组合，厚度可达30 ms的双向时间，在地震剖面上具有“一串珍珠”的形状。位于台地边缘的亮点呈NW向间断带状分布，而在开阔台地则呈散在分布。亮点主要分布在长兴组顶部和平台边缘和开放平台环境中。亮点的分布与位于长兴组上段高古地理区域的礁滩具有良好的耦合性。岩心、薄片和地球物理资料综合分析表明，“珍珠状”亮点是后成因形成的针状溶孔、小溶洞、缝洞囊性溶洞和花斑状溶洞系统的标志。岩溶。发生在二叠纪末段的海平面大规模海退是外露古隆起受外生岩溶作用的礁滩的主要控制。