Study on Nano Calcium Silicate Hydrate Used as Oil Well Cement Accelerator
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摘要: 纳米材料对水泥水化有促凝作用，近几年研究的重点为纳米级二氧化硅，但高的比表面积使其对水泥浆体增稠明显。水化硅酸钙晶种是采用人工合成的纳米级水化硅酸钙，其成核作用可以加速水泥的水化反应，因此，以四水硝酸钙和五水偏硅酸钠为原料，通过沉淀反应制备水化硅酸钙晶种，并开展了晶种作为油井水泥促凝剂的研究。结果表明，在10℃下，采用Tam air微量热仪对水泥水化热和水化速率进行了96 h不间断测试，随着晶种添加量的增加，水泥水化的诱导期呈现明显缩短趋势，放热量呈现增加趋势；用超声波强度分析仪实时跟踪水泥石强度的发展过程表明，加入晶种后起强度的时间明显缩短，水泥石强度发展速率得到了明显提升，且随着晶种添加量的增加，趋势更加明显；而水泥浆黏度并没有随着晶种添加量增加而呈现出明显的增加趋势。因此，水化硅酸钙晶种具有加速水泥水化反应、提高水泥石早期强度以及缩短静胶凝过渡时间的特点，是一种具有应用潜力的低温促凝剂。Abstract: Nano material is able to accelerate the hydration of cement. Nano silica has recently been widely studied for its use in well cementing. Nano silica accelerates the hydration of cement excessively because of its high specific surface area. Calcium silicate hydrate seed crystal, an artificially synthesized nano calcium silicate hydrate, can accelerate the hydration of cement through nucleation. Using Ca(NO3)2·4H2O and NaSiO3·5H2O as raw materials, a calcium silicate (C-S-H) seed crystal was developed through precipitation reaction, and study on the use of C-S-H as oil well cement accelerator was conducted. The heat of hydration and hydration rate of cement were measured unintermittently at 10℃ for 96 hours with Tam air isothermal calorimetry. It was found that with an increase in the concentration of the seed crystal, the induction time of cement hydration was notably shortened, and the amount of heat released was increasing. The developing progress of the strength of the set cement, measured with an ultrasonic strength analyzer in the study, indicated that the use of seed crystal notably shortened the time required for the cement slurry to develop strength, and the rate of strength development of the set cement increased obviously. The more the seed crystal used, the faster the development of the strength of set cement. It was also found that the addition of the seed crystal did not notably increase the viscosity of the cement slurry. From these studies it is understood that the C-S-H seed crystal is able to accelerate the hydration of cement, increase the early strength of set cement and shorten the induction time for gel strength development. It is a potential low temperature accelerator.
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Key words:
- Accelerator /
- Well cementing /
- Calcium silicate hydrate /
- Seed crystal
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[1] NELSON B ERIK,GUILLOT DOMINIQUE.Well cementing[M].Schlumberger,2006:50-54. [2] 孙晓杰,余纲,郑会锴,等.AMPS水泥浆体系低温促凝剂的研究[J].钻井液与完井液,2016,33(1):84-87.SUN Xiaojie,YU Gang,ZHENG Huikai,et al.Study on low temperature accelerator for cement slurry[J].Drilling Fluid &Completion Fluid,2016,33(1):84-87. [3] PANG XUEYU,BOUL PETER,CUELLO JIMENEZ WALMY.Nanosilicas as accelerators in oil well cementing at low temperatures[C].SPE 168037,2014. [4] ZHANG JIE,WEISSINGER A EMILY,PEETHAMPARAN SULAPHA,et al.Early hydration and setting of oil well cement[J].Cement and Concrete Research,2010,40(7):1023-1033. [5] 符军放,张浩,项先忠,等.硅溶胶在固井水泥浆中的应用性能研究[J].西安石油大学学报(自然科学版),2013,28(3):78-82.FU Junfang,ZHANG Hao,XIANG Xianzhong,et al.Study on the performance of colloidal silica for cementing slurry[J].Journal of Xi'an Shiyou University (Natural Science),2013,28(3):78-82. [6] 符军放,赵琥,项先忠.一种固井合成水泥石的研制与室内评价[J].钻井液与完井液,2015,32(2):61-63.FU Junfang,ZHAO Hu,XIANG Xianzhong.Development and evaluation of a compound set cement for well cementing[J].Drilling Fluid &Completion Fluid,2015,32(2):61-63. [7] 赵琥,邱超,宋茂林,等.深水固井低温水泥外加剂的开发及应用[J].石油钻探技术,2012,40(4):72-75.ZHAO Hu,QIU Chao,SONG Maolin,et al.Development and application of additive in deepwater cementing[J].Petroleum Drilling Techniques,2012,40(4):72-75. [8] THOMAS J JEFFREY,JENNINGS M HAMLIN,CHEN J JEFFREY.Influence of nucleation seeding on the hydration mechanisms of tricalcium silicate and cement[J].The Journal of Physical Chemistry C,2009,113(11):4327-4334. [9] SABINS L FRED,TINSIEY M JOHN,SUTTON L DAVID.Transition time of cement slurries between the fluid and set state[C].SPE 9285,1980. -
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