改性天然高分子基钻井液流变性研究

Study on Rheological Properties for Modified-natural-macromolecule Drilling Fluids

研究改性天然高分子基钻井液处理剂和体系的流变性有益于对其进一步研究和推广应用。试验测定了IND30、NAT20、NFA25加入4%膨润土基浆中配制的悬浮液,在1022、511、340.7、170.3、10.22、5.11s-1等6个剪切速率下的剪切力,以及钻井液体系在相同条件下的剪切力,确定了适合的流变方程及流变曲线。结果表明,0.2%以内加量的IND30悬浮液的流动特性接近于宾汉模型,0.3%以上加量的IND30悬浮液的流动特性接近于幂律模型;3%以内加量的NAT20悬浮液的流动特性接近于幂律模型;6.0%以内加量的NFA25悬浮液的流动特性接近于宾汉模型;依据正交试验设计的12个配方配制而成的悬浮液的流动特性都接近于幂律模型。

Studying rheological properties of the additives and system would help further study and application of the modified-natural-macromolecular drilling fluids. The suspending fluid mixed with modified-natural-macromolecular additives (IND30, NAT20, NFA25) and 4% bentonite fluid were experimentally detected. The tests included shearing force on 6 shear rates of 1022, 511,340.7,170.3, 10.22 and 5.11s-1 as well as the shearing force of drilling fluid system at the condition as stated. The rheologic properties and flow curves were found. The rheological properties of suspending fluid with dosage <0.2% IND30 are similar to Bingham model. The rheological properties of suspending fluid with dosage >0.3% IND30 are similar to Power model. The rheological properties of suspending fluids with addition <3 NAT20 are similar to Power model. The rheological properties of suspending fluids with dosage <6% NFA25 are similar to Bingham model. The rheological properties of drilling fluids prepared with 12 formulae according to orthorhombic designed formulations are all similar to the Power mode.