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川南X井区龙马溪组页岩气保存条件研究

Study on the Preservation Conditions of Shale Gas in the Longmaxi Formation of X Well Block, Southern Sichuan

刘欣莹¹, 杨西燕¹, 谢圣阳², 张成林², 范存辉¹

Environment and Resource / 2026,8(2): 251-256 / 2026-05-22 49 35

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• Information:

  1．西南石油大学 地球科学与技术学院，成都；
  2．中国石油西南油气田页岩气研究院，成都

• Keywords:
  Southern Sichuan Basin; Longmaxi formation; Preservation conditions; Shale gas; Structural characteristics
  川南地区; 龙马溪组; 保存条件; 页岩气; 构造特征
• Abstract: The Longmaxi Formation shale gas in the X well block, southern Sichuan Basin, has enormous resource potential. Clarifying its preservation conditions is of great significance for exploration deployment. Based on key parameters including structural characteristics, fault systems, natural fracture development, burial depth and formation pressure, this study systematically evaluated the shale gas preservation conditions in the study area. The results show that: synclinal areas, characterized by weak structural transformation and good sealing, are favorable preservation units; anticlines and slope areas, where imbricate thrust faults and “Y-shaped” fault systems are developed, are unfavorable for preservation. The Indosinian near-EW-trending faults exhibit poor sealing in the present-day stress field, while the Himalayan NE- and SN-trending faults show good sealing. Grade-II faults exert the strongest destructive effect within 1 km of their surrounding areas, whereas Grade-III and Grade-IV minor faults have negligible influence. In synclinal areas, network fractures are characterized by low density and small scale, indicating excellent preservation; in anticlines and fault zones, unidirectional fractures are highly developed with strong connectivity, easily forming gas migration pathways. The study area features moderate burial depth and strong overpressure, which are favorable for shale gas preservation. Integrating the above factors, the study area was divided into three categories of favorable preservation areas, providing a solid geological basis for subsequent exploration and development. 川南X井区龙马溪组页岩气资源潜力巨大，明确其保存条件对勘探部署具有重要意义。本文基于构造特征、断裂体系、裂缝发育、埋深与地层压力等关键参数，系统评价了该区页岩气保存条件。结果表明：向斜区构造改造弱、封闭良好，为有利保存单元；背斜及斜坡区发育叠瓦状逆冲及“Y”型断裂系，不利于保存。印支期近EW向断裂现今封闭性差，喜山期NE、SN向断裂现今封闭性好。Ⅱ级断层对周边1km范围内破坏最强，Ⅲ、Ⅳ级小断层影响微弱。向斜区网状缝密度低、规模小，保存优良；背斜及断裂带单向缝密度高、连通性强，易构成逸散通道。区内埋深适中，处于强超压背景，利于保存。综合上述因素，将X井区页岩气保存有利区划分为3类，为研究区后续勘探开发提供了地质依据。
• DOI: 10.35534/er.0802034 (registering DOI)
• Cite: 刘欣莹，杨西燕，谢圣阳，等．川南X井区龙马溪组页岩气保存条件研究［J］．环境与资源，2026，8（2）：251-256.