低软化点防塌减阻剂研究及在复杂地层中的应用

为解决现有沥青类防塌剂软化点高及较低温度条件下润滑性差等问题,采用沥青及石油树脂等为主要原料,研制出软化点30℃~60℃可调的防塌减阻剂GFT。室内性能评价表明,GFT具有胶体稳定性好、软化点低、乳液粒径小及润滑能力强等特点,而且与冲洗液配伍性强,不会明显增加冲洗液的粘度,并能有效地降低冲洗液的滤失量。在淡水膨润土基浆中加入1%软化点为46℃的防塌减阻剂,基浆的润滑系数降低率达69%。经在山东及安徽等地多个复杂地层钻孔中现场应用,证明了防塌减阻剂GFT对松散破碎地层、见水易分散地层及硬碎地层具有良好的护壁效果,同时能较好地降低钻具扭矩及摩擦阻力。

Application of the anti-collapse and anti-drag agent with low softening point to complex strata

In order to solve the problems that existing asphalt anti-caving agent of having high softening point and poor lubricity at relatively low temperature, an anti-collapse and anti-drag agent GFT with adjustable softening point at 30oC~60 oC is developed by using asphalt and petroleum resin. The indoor experiments show that GFT exhibits the excellent colloidal stability, low softening point, small emulsion particle and good lubricity. Moreover, it has strong compatibility with the flushing fluid system, does not increase the viscosity of drilling fluid and also efficiently reduces the filtration loss. When the 1% GFT with softening point at 46oC is added into bentonite dispersion, the lubricity coefficient reduction rate of bentonite dispersion is 69.4%. Eventually, field applications of GFT in several complex strata boreholes of Shandong and Anhui indicate GFT is a good anti-caving agent which can solve the instability of boreholes in loose and broken formations and strong water-sensitivity strata, and reduce the torque and frictional resistance in drilling.