耐高温高密度防腐固井水泥浆

深层含酸性气体油气井中，高温、高压含CO₂气体环境易腐蚀水泥石，破坏水泥环密封完整性。为开发具有防腐能力的高温高密度固井水泥浆体系，对水泥浆关键材料进行研究，构建了抗高温高密度防腐水泥浆体系，分析了水泥浆性能和微观形貌。实验结果表明，锰矿粉加重剂能显著提高水泥浆密度，制备的水泥浆体系高温下抗腐蚀能力较好；研究的降失水剂JS18L、缓凝剂H16L在高温下能降低水泥浆失水量，调节稠化时间。将无机复合防腐剂NAM-H、聚合物防腐剂SZ-M2结合使用，作为防腐材料可增强水泥石防腐性能。使用研究的添加剂材料构建密度为1.90～2.20 g/cm3的抗高温高密度防腐水泥浆，水泥浆体系流变性好，稳定性高，失水量小于50 mL，稠化时间在3～5 h可调，满足固井作业要求。高密度水泥石高温下力学性能稳定，防腐能力强，水泥石腐蚀30 d的抗压强度衰退率在25%以内，腐蚀深度小于1.5 mm。该研究成果可为高温高压酸性气井以及二氧化碳地质封存井固井作业提供技术支持。 

High Temperature High Density Cement Slurry with Corrosion Inhibition Property

CO₂ gas in the deeper part of a high temperature high pressure well generally causes corrosion to the set cement and damages the sealing integrity of the cement sheath. To develop a high temperature high density cement slurry with high corrosion inhibitive capacity, studies were conducted on the key cement materials, and a high temperature high density cement slurry with high corrosion inhibitive capacity was formulated. Analyses of the performance and micro morphology of the cement slurry show that manganese ore powder weighting material can remarkably increase the density of a cement slurry, and the cement slurry also has good corrosion inhibition property at high temperature. In formulating the cement slurry, a filter loss reducer JS18L was used to control high temperature filtration rate, and a cement retarder H16L was used to control thickening time. The corrosion inhibitive capacity of the cement slurry was improved with the use of an inorganic corrosion inhibitor NAM-H and an organic corrosion inhibitor SZ-M2. Using these materials, a high temperature high density (1.90-2.20 g/cm3) cement slurry was formulated. The new cement slurry has good rheology, good stability, low filter loss of less than 50 mL and thickening time adjustable between 3 h and 5 h. The high density set cement at high temperatures has stable mechanical properties and good corrosion inhibitive capacity. The deterioration rate of the 30 d compressive strength of the set cement is less than 25%, and the depth of corrosion is less than 1.5 mm. The results of the study provide technical support to the cementing of high temperature high pressure wells with acid gases and CO₂ geological sequestration wells.