超高温井固井水泥浆体系研究与应用

Study on cement slurry system in ultra-high temperature well

摘要:

针对目前高温水泥浆抗高温外掺料以石英砂为主，水泥石200 ℃下高温强度衰退导致环空密封失效问题，研发了具有水化活性的富硅铝材料，其加量占水泥30%~70%时200 ℃×20.7 MPa×30 d下水泥石高温强度不衰退；将富硅铝材料作为水泥石高温强度稳定材料，优选配套外加剂，构建了富硅铝基超高温固井水泥浆体系，100~200 ℃下API失水量<50 mL，稠化时间150~500 min可调，水泥浆综合性能良好；水泥石200 ℃×20.7 MPa养护10、60、120、180 d抗压强度均>26 MPa，未见高温强度衰退。超声波强度曲线显示600 h内水泥石强度持续增长直至稳定发展，水泥石高温力学性能优异。SEM和XRD分析表明富硅铝材料参与水泥水化反应，消除体系中氢氧化钙，生成高温性能优良的铝氧四面体和硅氧四面体相互键接的空间三维网状结构，以及托勃莫来石、钙硅铝石等水化产物维持水泥石的高温强度稳定，水泥石结构致密。该水泥浆体系在干热岩固井中应用1个井次，固井质量优质，截至目前1000 d水泥环密封良好。

Abstract:

Aiming at the strength of set cement with sand degradation leads to the annular seal failure at 200℃， rich silica-aluminum material with hydration activity was developed， and when the adding amount for 30% to 70% of cement ，the compressive strength of cement are stable at 200℃×20.7MPa×30d. Based on the rich silica-aluminum material as a high temperature stabilizer， selecting matching additives， the rich silica-aluminum ultra-high temperature cement slurry was developed， the API water loss is less than 50mL at 100~200℃， the thickening time can be adjustable between 150~500min， the comprehensive performance is good. Compressive strength of set cement cured for 10d， 60d， 120d， 180d under 200℃×20.7MPa are all greater than 26MPa， and high temperature strength decline was not observed. The ultrasonic strength curve shows that the strength of set cement grows steady within 600h. The SEM and XRD shows that， the rich silica-aluminum material participate in the cement hydration reaction， and eliminate the calcium hydroxide， and generate aluminum-oxide tetrahedron and silica-oxide tetrahedron inter-bonding three-dimensional network structure with good high temperature performance， and together with tobermolite calcium silicate bauxite to maintain the stability of the high temperature strength of cement stone. The cement slurry system has been applied in hot dry rock cementing for 1 well， and the cementing quality is good. As so far， the cement ring has been well sealed for 1000 days.