摘要
南海莺琼盆地不但要面临180℃的超高温,还要面临高浓度CO_(2)的挑战。然而,加砂水泥水化产物在超高温CO_(2)环境下变化复杂,导致其强度衰退机理仍不清楚。因此,对超高温CO_(2)环境中改性水泥石的力学性能、矿物组成及微观形貌进行分析。结果表明:随着腐蚀时间的延长,水泥石的腐蚀深度一直增大,抗压强度一直降低,渗透率先降低后增大,SiO_(2)和C_(2)SH含量一直降低,C_(6)S_(6)H和CaCO_(3)含量一直增大,C_(6)S_(6)H的形貌由堆积的针状向着片状和块状转变。腐蚀初期,C_(2)SH和C_(6)S_(6)H被腐蚀生成CaCO_(3)和少量无定形SiO_(2),同时部分C_(2)SH会转变为更耐腐蚀的C_(6)S_(6)H,该阶段导致水泥石渗透率降低,C-S-H凝胶的聚合度增大。腐蚀后期,C_(6)S_(6)H和其他C-S-H凝胶被大量腐蚀,且CaCO_(3)溶解,使水泥石渗透率增大,C-S-H凝胶聚合度降低,导致水泥石抗压强度大幅降低。
Yingqiong Basin in the South China Sea not only faces the ultra-high temperature of 180℃,but also faces the challenge of high concentration of CO_(2).However,the hydration products of sand-added cement change complex under ultra-high temperature CO_(2)environment,resulting in its strength decline mechanism is still unclear.Therefore,through the analysis of mechanical properties,mineral composition and micromorphology of modified cement stone in ultra-high temperature CO_(2)environment,it is shown that with the increase of corrosion time,the corrosion depth of cement stone has been increased,the compressive strength has been decreased,and the permeability has been increased after the first decrease.The contents of SiO_(2)and C_(2)SH have been decreasing,while the contents of C_(6)S_(6)H and CaCO_(3)have been increasing,and the morphology of C_(6)S_(6)H has changed from acicular to flake and block.At the initial stage of corrosion,C_(2)SH and C_(6)S_(6)H are corroded to generate CaCO_(3)and a small amount of amorphous SiO_(2),while part of C_(2)SH will be transformed into more corrosion-resistant C_(6)S_(6)H.At this stage,the permeability of cement decreases and the degree of polymerization of C-S-H gel increases.At the later stage of corrosion,C_(6)S_(6)H and other C-S-H gels were heavily corroded,and CaCO_(3)dissolved.The permeability of cement increases and the degree of C-S-H gel polymerization decreases.The compressive strength of cement is greatly reduced.
作者
袁彬
赵清立
徐璧华
冯青豪
杨川
YUAN Bin;ZHAO Qingli;XU Bihua;FENG Qinghao;YANG Chuan(National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Oilfield Chemicals R&D Institute,COSL,Yanjiao 065201,Hebei,China;Petrochina Chuanqing drilling engineering Co.,Ltd.,Downhole Operation Company,Chengdu 610500,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2024年第S02期160-164,共5页
Materials Reports
基金
国家自然科学基金青年科学基金(52204014)
四川省青年基金项目(2023NSFSC0926)。
