负温固井用锂盐-硫铝酸盐水泥浆体系

Lithium Salt-Sulfoaluminate Slurry System for Negative Temperature Cementing

针对负温环境下固井常用水泥石强度发展缓慢甚至停止水化的问题,对锂盐(TSL)-硫铝酸盐水泥(SAC)浆体系开展了浆体性能及在4℃&-10℃下的水泥石力学性能研究,测试了水泥的水化温升及累计放热量。通过X射线衍射仪(XRD)、热重分析仪(TG/DTG)和扫描电子显微镜(SEM)对水泥的水化过程进行了分析,论证了TSL-SAC水泥浆体系在负温固井工程中应用的可行性。结果表明:TSL-SAC水泥浆体系浆体性能较好,在TSL掺量为SAC的3%时,在4℃环境下,48 h抗压强度可达23.01±0.47 MPa,在-10℃环境下,48 h抗压强度可达3.98±0.07 MPa,满足固井施工要求。同时,通过引入温控材料有效降低了水泥的水化温升及累计放热量,最大水化温升降低了27.62%,最大水化温升延迟320.67%出现。TSL促进SAC水化反应进行的机制在于增加了水泥石中凝胶态水化产物铁胶及铝胶的生成量,促进了AFt的生长结晶,形成低结晶度的CaCO_(3)保护层并减少CH被碳化。实验结果表明,TSL-SAC水泥浆体系具备在负温固井环境下应用的潜力。

Aiming at the problem that the strength of cement pastes commonly used in cementing under negative temperature environment develops slowly or even stops hydration,this paper studies the slurry properties of lithium salt(TSL)-sulfoaluminate cement(SAC)slurry system and the mechanical properties of cement stone at 4℃and-10℃,and tests the hydration temperature rise and cumulative heat release of cement.The hydration process of cement was analyzed by X-ray diffractometer(XRD),thermogravimetric analyzer(TG/DTG)and scanning electron microscope(SEM),and the feasibility of application of TSL-SAC cement system in negative temperature cementing project was demonstrated.The results show that the slurry performance of TSLSAC cement slurry system is well.When the content of TSL is 3%of SAC,the 48 h compressive strength can reach 23.01±0.47 MPa at 4℃and 3.98±0.07 MPa at-10℃,which meets the requirements of cementing construction.At the same time,the hydration temperature rise and cumulative heat release of cement were effectively reduced by the introduction of temperature control materials.The maximum hydration temperature rise was reduced by 27.62%,and the maximum hydration temperature rise delay was 320.67%.The mechanism of TSL promoting the hydration reaction of SAC is that it increases the generation of gel hydration products of iron glue and aluminum glue in cement stone,promotes the growth and crystallization of AFt,forms a low crystallinity CaCO_(3) protective layer and reduces the carbonization of CH.TSL-SAC cement slurry has the potential of application in negative temperature cementing environment,and this study provides a certain experimental and theoretical basis for cementing in negative temperature area.