硅灰耐高温低密度水泥浆的研究

用硅灰作高温稳定剂,漂珠为减轻剂,与G级油井水泥配制密度为1•5g/cm3的水泥浆。该水泥浆的特点是:①密度低,用水量小;②在低温下强度高、滤失量低、析水为零、稠化时间可调、流变性好,能满足施工工艺的要求;③水泥石能承受高温,在350℃、20MPa下养护3天,强度达12MPa。该低密度水泥浆可用于低压易漏地层稠油热采井的固井,并可大大减轻因高温引起的水泥石强度衰退,延长油井的寿命。

Study of High-temperature Lightweight Cement Slurry with Silica Fume

A cement slurry, whose density was 1.5 g/cm3, had been prepared using class-G oil-well cement with silica fume as a thermo stabilizer and microsphere as light-weight admixture. After curing at 45℃and atmospheric pressure for 48 hours, the cement slurry displayed a compressive strength of 15 MPa; the water loss ( at 7 MPa for 30 min. ) was less then 250 ml and no free water was observed. After curing at 350℃and 20 MPa for 3 days, the cement slurry had a compressive strength of more than 10 MPa. Such a temperature-resistant, lightweight cement slurry can be used for well cementing in low-pressure, viscous oil reservoirs planned for thermal recovery to considerably reduce the high temperature-induced strength decline of the cement and prolong the life span of the producing well.