膨润土接枝聚合物降滤失剂研究

Preparation of Polymer Grafted-on-Bentonite as Filtrate Loss Rudcer for Water Base Drilling Fluids

通过丙烯酸和含酰胺基团的共聚单体在膨润土悬浮液中的氧化还原体系引发共聚合 ,制备了膨润土接枝共聚物 ,用作水基钻井液的降滤失剂。由接枝产物水悬浮液的表观粘度、塑性粘度、动切力及滤失量 ,接枝产物处理的粘土浆的性能 ,初步确定了接枝产物的合成条件 :单体、膨润土质量比 0 .4 5∶1;丙烯酸、共聚单体摩尔比 1.6∶1;接枝共聚温度 75℃。比较了该接枝产物、在相同条件下制备的共聚物与膨润土的混合物及一种商品聚合物降滤失剂HGST 5 98作为降滤失剂的性能 ,发现接枝产物处理的粘土浆的API滤失量特别是HTHP滤失量大大低于共聚物 膨润土混合物和HGST 5 98处理的粘土浆 ,这 3种降滤失剂在水中的增粘能力排列顺序为 :HGST 5 98>共聚物 膨润土混合物 >该接枝产物。图 3表 6参 6。

Through redox initiated copolymerization of acrylic acid and an amido group bearing monomer in aqueous bentionite suspension a copolymer grafted onto bentonite (CPgB) is prepared as filtrate loss reducer (FLR) for water base drilling fluids. According to measurements of apparent and plastic viscosity, yield stress, and filtrate loss of CPgB suspension in water and behavior of a bentonite mud treated by CPgB, the conditions of synthesis of CPgB is estabilished preliminarily as follows: monomers to bentonite mass ratio 0.45∶1; acrylic acid to comonomer molar ratio 1.6∶1, temperature of graft copolymerization 75℃. A comparision is made between the CPgB, a mixture of bentonite with a copolymer of acrylic acid with the comonomer prepared at the same conditions (CP+B), and a commercial polymeric FLR, HGST 598, as FLRs and shows that the API and particularly HTHP filtrate loss of CPgB treated mud is much lower than that of mud treated by CP+B and HGST 598 and the viscosifying capacity for water is arranged in order HGST 598>CP+B>CPgB.