新型丙烯酰胺共聚物油井水泥降失水剂研究

Study of new filtrate reducer of acrylamide copolymer used for cementing

针对常用降失水剂在工程应用中存在低于临界掺量时滤失失控，配套外加剂可选范围小，室内测试的滤失量数据难以代表井下实际情况，水泥胶结测井解释困难，对高含水、裂缝性和高渗透地层很难实现优质封隔的问题，合成了以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）与丙烯酰胺（AM）的共聚物为主体的降失水剂，并对其降滤失能力、稠化性能、抗压强度、抗盐性能进行了评价。研究表明，该聚合物可靠的使用温度为井底静止温度120℃．循环温度在50—90℃范围内，在水泥中单独掺入0．32％-0，80％的聚合物可将API滤失量控制在50mL以内。现场试验表明该类聚合物适用于一次封固段长不超过600m的油气井固井，也有利于高含水层、浅气层和高渗透地层的优质封隔。

Aim at the difficulty of separate layer to high auifer bed,fractured and high permeability formation,The copolymer which made from 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and acrylamide (AM) was synthesized, which are root of the chemical character of polyvinyl alcohol (PVA). Examination results in laboratory show that the credible application temperature of the copolymer is 120℃ and the API fluid loss of slurry will less than 50 mL while the dosage of the copolymer in cement in the range of 0.32～ 0.80 at the temperature ranging from 50 to 90℃. The evidences of field application indicate that this copolymer can be used for primary cementing job that the length of cementing is less than 600 m. It is propitious to isolate the high aquifer formation, shallow natural gas layer and high permeability formation.