钻井液降粘降滤失剂MGAC-2的研制

Preparation of Viscosity/Fluid Loss Reducing Additive MGAC-2 for Water-Base Drilling Fluids

按下述路线在室内合成了兼具降粘和降滤失功能的水基钻井液处理剂MGAC 2 :将本质素磺酸钙与甲醛反应 ,再在硝酸铈铵催化下使丙烯酰胺、马来酸在木质素磺酸钙缩合产物上接枝共聚 ,提纯接枝共聚物 ,先与硫酸亚铁进行络合反应 ,再与甲醛、亚硫酸钠进行磺甲基化反应 ,分离出反应产物并干燥 ,得到降粘降滤失剂MGAC 2。用红外光谱确证了产物的接枝共聚结构。室内钻井液性能检测结果表明 :0 .5 %MGAC 2可使淡水膨润土基浆的表观粘度下降 5 0 %,API滤失量下降 5 1%,动切力下降 80 %,静切力下降幅度更大 ;0 .5 %MGAC 2处理的钻井液可抗 3%NaCl,0 .9%CaCl2 ,抗盐抗钙能力优于FCLS ;在室温、12 0℃、140℃、180℃下 12小时的静态老化实验中 ,MGAC 2的抗温性能优于FCLS ;大庆油田一口井的储层岩心在 0 .5 %MGAC 2水溶液中浸泡后的回收率 ,明显高于在 0 .5 %FCLS水溶液中浸泡后的回收率。

The titled bifunctional drilling fluid additive MGAC-2 is synthesized in laboratory by following procedures: calcium lignosulfonate CaLS is reacted with formaldehyde and acrylamide and maleic acid are graft-copolymerisized onto the CaLS-CH 2O condensate at the presence of cerium-ammonium nitrate; the purified graft-copolymer is complexed with ferrous sulfate and then sulfomethylated by formaldehyde and sodium sulfite; the reaction product isolated and dried to obtain visosity/fluid loss reducing agent MGAC-2. The structure of the graft-copolymer is identified IR-spectrometrically. The laboratory evaluation of performance properties shows that: introducing 0.5%MGAC-2 into a basic bentonite mud lowers its η a by 50%, API filtration loss by 51%, yield point by 80%, and gel strength much more; the mud treated by 0.5% MGAC-2 is more tolerant to NaCl(3%) and to CaCl 2(0.9%) and is more thermally resistant in 12 hrs ageing experiments at ambient temperature and at 120℃,140℃, and 180℃ than 0.5% FCLS-treated one; the recovery rate of a reservoir core sample from Daqing in 0.5% MGAC-2 aqueous solution is notably higher than that in 0.5% FCLS solution.