稀硅酸盐钻井液防塌性能的影响因素

以多种稀硅酸盐水溶液和泥浆进行了页岩分散试验和页岩稳定指数试验.结果表明：防塌钻井液所用的硅酸盐模数以2.8～3.2为好,加量在2%～5%较好;当用于含KCl的泥浆中时,硅酸盐的钠、钾比例对防塌性能的影响不显着;适量的无机盐可与硅酸盐产生协同作用提高防塌性能,但钙离子过量会破坏泥浆性能.有机处理剂和粘土主要影响硅酸盐钻井液的流变性和滤失性能,而对防塌性能基本上无直接影响.地层特性是影响稀硅酸盐钻井液防塌效果的最复杂因素.

FACTORS ON THE HOLE-STABILIZING PROPERTY OF DILUTED SILICATE DRILLING FLUIDS

The shale dispersion tests and shale stabilization index (SSI) tests with silicate solutions and silicatebased muds show: the molecular ratios of silicates for holestabilizing muds are preferably 2832, and their preferable feeding quantities are 2%5%(v/v). The Na/K proportion of the silicate in a mud containing KCl has little effect on its holestabilizing capacity. Salts can synergically increase the holestabilizing ability of silicatebased muds, but Ca2 may badly change the mud rheology. Organic additives and clays mainly affect muds rheological and filtration properties will not changing the holestabilizing results. The relations between the formation characteristics and the holestabilizing capacities of silicatebased muds must be more important and complex, which need further research.