抗H_2S腐蚀外掺料在油井水泥中的研究

Study on anti-H_2S corrosion admixture for oil well cement

为改善油井水泥石抗H2S腐蚀能力,研究了外掺料FB和CB(铁族化合物)对油井水泥抗腐蚀性能的影响。通过对腐蚀前后水泥石抗压强度、渗透率、孔结构(MIP法)等性能的测试和水泥石样品的微观形貌及腐蚀产物成分分析,评价两种外掺料对油井水泥石的抗腐蚀性能的影响。结果表明:80℃下,H2S溶液腐蚀养护至28d,FB掺量为10%时,抗压强度达26.52MPa,比净浆水泥石提高35.6%,CB掺量为3%时,达29.86MPa,比净浆水泥石提高52.7%;FB和CB的掺入能有效降低水泥石有害孔(>100nm)比例,且孔径分布趋于无害孔(<50nm);FB和CB的掺量为10%时水泥石在7MPa驱替压力下的渗透率为零(原浆水泥石为0.96×10-3μm2)。FB和CB的掺入有利于水泥石抗H2S腐蚀能力的提高。

In order to improve the ability of anti-H2S corrosion of oil-well cement,the effects of FB and CB admixture（iron race compounds） on corrosion resistance properties of oil well cement were studied.In order to evaluate the effect of admixture,the compressive strength,permeability and pore structure（MIP）of cement before and after corrosion were tested and the micro-morphology and corrosion product component of cement paste sample were analyzed.The results indicated that after 28d curing in H2S solution under 80℃,the compressive strength of the cement paste admixed with 10% FB could reach to 26.52MPa,which increased by 35.6% comparing with the blank cement paste.Identically,the compressive strength of the cement paste admixed with 3% CB could reach to 29.86MPa,which increased by 52.7% comparing with the blank cement paste.Furthermore,the admixture of the FB and CB could decrease the ratio of harmful pores（100nm） effectively,and pore size distribution tends to be harmless pores（50nm）.The permeability would decrease to zero comparing to 0.96×10-3μm2 net cement paste when both FB and CB in the cement stone samples was 10% and 7MPa pressure.The FB and CB was favorable to improve the ability of anti-H2S.corrosion of oil-well cement