煤层气储层伤害和井壁失稳分析及钻井液技术研究现状

Analysis of coalbed methane reservoir damage and wellbore instability and research status of drilling fluid technology

摘要:

煤层气储层独特的“三低特性”和双重孔隙结构，使其在钻井过程中极易遭受应力敏感、水敏及固相侵入等不可逆伤害，并面临严峻的井壁失稳风险。本文系统分析了煤岩特殊的物理化学性质及其对钻井液的特定要求，深入阐述了钻井液对储层的损害机理及对井壁稳定性的影响。重点综述了煤层气钻井液技术的研究进展：针对储层保护，形成了低密度钻井液、强抑制-封堵体系、低固相/无固相钻井液及可降解钻井液等核心技术；针对井壁稳定，发展了基于多元协同抑制和高效封堵的防塌钻井液体系。文章总结了当前技术面临的挑战，并指出未来应加强地质适配性、智能响应型钻井液、高效环保材料等研究，为优化煤层气钻井液技术、提升开发效益提供参考。

Abstract:

Due to the unique “three-low characteristics” and dual-pore structure of coalbed methane （CBM） reservoirs， they are extremely prone to irreversible damage such as stress sensitivity， water sensitivity， and solid-phase invasion during drilling， and face severe risks of wellbore instability. This paper systematically analyzes the special physical and chemical properties of coal rocks and their specific requirements for drilling fluids， and deeply expounds the damage mechanism of drilling fluids on reservoirs and their impact on wellbore stability. The research progress in CBM drilling fluid technology is mainly reviewed： for reservoir protection， core technologies such as low-density drilling fluids， strong inhibition-plugging systems， low-solids/no-solids drilling fluids， and degradable drilling fluids have been formed； for wellbore stability， anti-collapse drilling fluid systems based on multi-component synergistic inhibition and high-efficiency plugging have been developed. The paper summarizes the current technical challenges and points out that future research should focus on geological adaptability， intelligent-responsive drilling fluids， high-efficiency environmental protection materials， etc.， to provide a reference for optimizing CBM drilling fluid technology and improving development benefits.