Abstract:

The rheological property of oil-based drilling fluid is seriously deteriorated by the continuous intrusion of poor solid phase such as formation soil, and it is difficult to effectively deal with it by solvent extraction, thermal distillation and other technologies, which will cause waste of resources. In order to realize the reuse of waste oil-based drilling fluid, quaternization and hydrophobic modification were carried out with hyperbranched polymer as the main flocculant, and oil-soluble flocculant with good selectivity was prepared. The molecular structure and thermal stability of the flocculant were determined by infrared spectroscopy, thermogravimetric analysis and other methods, and the effects of the addition of the flocculant on the density, solid phase content and rheological properties of drilling fluid were explored. The flocculant mechanism was analyzed by zeta potential and mineral component analysis. The results showed that when the dosage of flocculant was 1.0‰, the inferior solid phase in the drilling fluid system could be effectively flocculated and deposited, the solid phase clearance rate of the two kinds of oil-based drilling fluid after waste treatment could reach 80.6% and 63.8%, and the density of the treated drilling fluid was 0.733g/cm³ and 0.745g/cm³, respectively. The compatibility and rheology of the treated drilling fluid could meet drilling requirements. It could realize the recycling of drilling fluid.

Key words: oil-based drilling fluid, drilling cuttings, flocculant, hyperbranched polyamide amine, regeneration cycle

摘要：

油基钻井液受地层土等劣质固相的不断侵入，流变性能严重恶化，采用溶剂萃取、热蒸馏等技术难以有效处理，会造成资源浪费。为实现对废弃油基钻井液的再生利用，本文选取超支化聚合物作为絮凝主剂，进行季铵化和疏水改性，制得具备良好选择性的油溶性絮凝剂；通过红外光谱、热重分析等方法测定了絮凝剂分子的结构与热稳定性，探究了絮凝剂加量对钻井液密度、固相含量和流变性能的影响，通过zeta电位和矿物组分分析，进行了絮凝剂的絮凝机理分析。结果表明：絮凝剂加量1.0‰时，可有效絮凝、沉淀钻井液体系中的劣质固相，对两种油基钻井液废液处理后固相清除率可达到80.6%和63.8%，处理后钻井液密度分别为0.733g/cm³和0.745g/cm³，其配伍性和流变性能满足钻井要求，可实现钻井液的再生循环利用。

关键词: 油基钻井液, 钻屑, 絮凝剂, 超支化聚酰胺胺, 再生循环