钻井液增黏剂CX-215及固相组成的降滤失研究

Effect of Viscosifier and Solids Composition on Filtration Property of Drilling Fluid

以增黏剂、加重剂及膨润土含量为变量因素,考察了钻井液在不同压差下的滤失特性,以研究压差对某种因素的降滤失效果的影响。结果表明,增黏剂CX-215的降滤失作用不受压差的影响;加重剂的粒径分布对滤失的影响在压差为2.0 MPa时达到最大,然后随着压差的增大影响越来越小,压差超过2.0 MPa时,体系的固相颗粒粒径分布对滤失的影响越来越小;在低压区间,增加膨润土对降滤失的贡献随着压差的增加而变小,在压差大于1.0 MPa时,膨润土含量对滤失的影响越来越大,即在高压下提高膨润土含量可以降低滤失量。此外,对优化刚性固相颗粒的降滤失作用和膨润土的降滤失作用进行了机理分析。

The filtration equation of drilling fluid takes several factors into consideration, except the composition of drilling fluid. A study is conducted on the effect of solid composition and viscosifier presented in drilling fluids on the filtration property of drilling fluids under different pressures, and a relative ratio, f, is defined to characterize the effect of different factors considered. The study shows that the differential pressure plays no role in the filtration control of a viscosifier, CX-215. At differential pressure of 2.0 MPa, the size distribution of weighting agents has the greatest effect on the filtration property of drilling fluid. At differential pressures greater than 1.0 MPa, bentonite plays more and more important role in filtration control. Moreover, analysis is done on the mechanism of filtration control using rigid particles.