超高温固井水泥浆降失水剂的合成与性能

为实现超深井与复杂井超高温固井水泥浆体系的构建目标，突破常规固井水泥浆降失水剂的超高温控失水瓶颈，研制开发了超高温水泥浆降失水剂F-SHT，并对其进行了结构表征与性能评价。结果表明，F-SHT的数均分子量为21 475 Da，表观黏度低，不影响水泥浆的配制；在温度达到294℃时开始发生明显热失重，表明其分子链热稳定性良好；有效控失水温度可达240℃且可抗饱和盐水，采用水泥浆静态失水量评价方法，测得240℃/6.9 MPa下饱和盐水水泥浆API失水量为38 mL。测试了F-SHT在水泥浆体系中的综合性能，停开机、稳定性与API失水评价结果均合格。F-SHT在河探1井Φ177.8 mm尾管固井中成功应用，结果表明F-SHT现场适应性良好，固井质量良好，同时为超深层油气资源的勘探开发提供了有力支撑。

Synthesis and Study of an Ultra-High Temperature Filtrate Reducer for Cement Slurries

An ultra-high temperature filtrate reducer, F-SHT, was developed for formulating cement slurries used in ultra-deep wells and complex wells with ultra-high well temperatures. The development of F-SHT has broken through the bottleneck of ultra-high temperature water loss control of conventional filter loss reducers for cement slurries. Characterization of the molecular structure and performance evaluation of F-SHT showed that F-SHT has a number average molecular weight of 21,475 Da and low apparent viscosity which is benefit to the formulation of cement slurries. Significant thermal weight loss occurred when the temperature reaches 294 ℃, indicating that the molecular chains of F-SHT has good thermal stability. F-SHT can effectively control the fluid loss of cement slurries at temperatures up to 240 ℃ and in salt-saturated cement slurries. In static filtration test, a salt-saturated cement slurry treated with F-SHT had API filtration rate of 38 mL at 240 ℃/6.9 MPa. In general performance testing, the performance of the cement slurry at starting and halting of the machine, the stability and API filtration rate of the cement slurry were all qualified. In cementing the Φ177.8 mm liner string of the well Heshen-1, F-SHT performed successfully; the cement slurry best suited the situation of the well condition, the quality of the well cementing job was good, and the well cementing job provided a strong support to the exploration of oil and gas resources buried in ultra-deep formations.