钻井液对孔隙型砂岩动滤失量影响因素的研讨

Study on the Influencing Factors of Drilling fluid on Filtration Loss in Porous Sand Cores

钻井液动滤失量和动滤失速率随时间变化情况是衡量钻井液对油气层损害程度重要指标之一。分别以高渗孔隙型、中高渗孔隙型和中渗孔隙型岩心作岩样,评价了加入具有不同粒径和粒度分布桥堵剂后对钻井液动滤失量及动滤失速率的影响情况。另外还分析了封堵剂对钻井液动滤失量的降低作用,以及温度、压差对钻井液动滤失量造成的影响。实验结果表明,在选择架桥粒子和填充粒子时,应采用多种粒径匹配,不能只依据岩心的d平均或d流动,50来确定,还必须考虑岩心的dmax和孔喉分布情况,对不同渗透率的岩心,由于其孔隙结构的差异,所选用的架桥粒子粒径和粒度分布情况亦有所差异;封堵剂是降低钻井液动滤失量主要组成之一,高温高压降滤失剂与架桥粒子、填充粒子、封堵剂相匹配,可有效降低钻井液动滤失量;动滤失量随温度升高和压差增大而增加。

This paper described the tests on the way to build up a tight mud cake on the surface of porous sand cores and to stop the dynamic filtration in a shortest time so that reduce the damaging effect of the filtration to minimum.The paper also analyzed the influences of temperature and pressure difference on dynamic filtration.