特深井钻井液微纳米有机封堵剂的研制及应用OA北大核心

An ultra-high temperature micro-nano organic plugging agent TSF is developed through a two-step reaction(pre-hydrolysis followed by free radical polymerization)with organic hydrolysable monomers and polymerization monomers such as AMPS,DMAA and BA.Thermogravimetric(TG)analysis shows that the initial thermal decomposition temperature of TSF is 240℃,indicating that TSF has excellent thermal stability.Before and after aging at 220℃,the particle sizes of TSF remain between 342 nm and 825 nm,indicating that TSF has dispersion stability.TSF has a glass transition temperature of 192℃,and can transform from the glassy state to the viscoelastic rubbery state,meaning that it has both plugging capacity through deformation and borehole wall strengthening capacity through adhesion.At 4%TSF treatment,a base drilling fluid,after aging at 220℃for 16 hours,can have its HTHP filter loss reduced by 43.1%,and have its HTHP filter losses tested on 5 μm and 10 μm ceramic sand discs reduced by 37.1%and 34.5%,respectively.These data show that TSF has excellent filtration control capacity through plugging.At 220℃,TSF produces no H2S,indicating that TSF has good safety performance at ultra-high temperatures.After aging at 220℃,the drilling fluid produced mud cakes whose permeability was reduced by 50.8%.Borehole wall strengthening effect through adhesion of TSF can increase the compressive strengths of core columns by 12.6-17 times,showing that TSF can enhance its ability to plug the fractures in the formations in ultra-deep wells through self-adaptability and to strengthen the borehole wall.These characteristics of TSF have been successfully applied in drilling the ultra-deep well A.