摘要
针对传统聚合物类降失水剂表观黏度大导致高密度水泥浆体系初始稠度过高,影响施工安全的技术性难题,以2-丙烯酰胺-2-甲基丙磺酸、乙烯基芳香羧酸、N,N-二甲基丙烯酰胺和丙烯酸为单体,通过自由基聚合法合成了一种四元低黏度降失水剂SCFL-W。产物的最佳合成条件为:反应温度75℃,pH值7,单体浓度19%,反应时间150min。利用红外光谱(FT-IR)确定了聚合产物的分子结构,通过热重分析(TGA)测得SCFL-W热分解温度大于380℃,表明其具有良好的热稳定性。机理研究表明,由于SCFL-W分子结构中含有烯烃键和苯环等刚性侧链,侧链之间难以形成缠结分支,有效降低聚合物黏度;其优异的控失水性能是低黏聚合物促进致密滤饼形成及芳环羧基静电吸附的协同效应。水泥浆性能表征显示,SCFL-W高温下黏度保持率高,与多种助剂配伍性能好,饱和盐水体系中240℃API失水量为45mL,抗盐性能优异,可用于1.88~2.4g/cm^(3)水泥浆体系。SCFL-W降失水剂现场应用3井次,固井质量优质,该降失水剂的成功应用为超高温高密度水泥浆的构建提供了新思路。
Traditional polymer filter loss reducers have high apparent viscosity,causing high density cement slurries to have excessive initial consistency and hence affecting negatively operation safety.To deal with this problem,a low viscosity quaternary copolymer filter loss reducer SCFL-W was developed with four monomers:2-acrylamide-2-methylpropanesulfonic acid,vinyl aromatic carboxylic acid,N,N-dimethylacrylamide and acrylic acid.The optimum reaction condition is:reaction temperature=75℃,pH=7,monomers’concentration=19%,and reaction time=150 min.The molecular structure of SCFL-W is determined with FT-IR and TGA used to measure the thermal decomposition temperature to be greater than 380℃,meaning that SCFL-W has good thermal stability.Mechanism study proves that in the molecular structure of SCFL-W there are rigid side chains such as olefinic bonds and aromatic rings,among them entangling branches are difficult to form,thereby reducing the viscosity of the polymer.The excellent filtration rate control performance comes from the synergistic effect between the dense mud cakes formed under the action of the low-viscosity polymer and the static adsorption of the aromatic ring carboxyl groups.Evaluation of the performance of cement slurries treated with the filter loss reducer shows that SCFL-W retains most of its viscosity at elevated temperatures and has good compatibility with many additives.SCFL-W has good salt resistance.At 240℃,it reduces the API filtration rate of a saturated salt cement slurry to 45 mL.SCFL-W can be used in cement slurries with densities ranging in 1.88-2.4 g/cm^(3).Three well-times of field application of SCFL-W show that the quality of well cementing jobs is excellent.The successful use of this filter loss reducer has provided a new clue to the formulation of ultra-high temperature high density cement slurries.
作者
汪晓静
徐春虎
魏浩光
苗霞
徐大伟
WANG Xiaojing;XU Chunhu;WEI Haoguang;MIAO Xia;XU Dawei(Sinopec Research Institute of Petroleum Engineering Co.,Ltd.,Beijing 102206;Sinopec Key Laboratory of cementing and completion,Beijing 102206)
出处
《钻井液与完井液》
北大核心
2025年第5期656-664,共9页
Drilling Fluid & Completion Fluid
基金
国家重点研发计划课题“井筒稳定性闭环响应机制与智能调控方法”(2019YFA0708303)。
关键词
降失水剂
低黏度
耐高温
高密度水泥浆
固井
Filter loss reducer
Low viscosity
High temperature resistance
High density cement slurry
Well cementing
