含煤地层植物胶冲洗液改性及机理研究

Study on modification of plant gum flushing fluid in coal-bearing strata and its mechanism

为改善植物胶资源日益枯竭对含煤地层等复杂地层冲洗液应用带来的不利影响,对瓜尔胶进行复配−交联改性研究。以黄原胶为复配增效剂,有机硼为交联改性剂,并辅以交联控制剂、无机处理剂,研发一种新型植物胶冲洗液(GXB),并对其进行一系列的性能评价。评价结果表明,GXB性能优良,能够满足含煤地层等复杂地层的钻进需求。采用红外光谱分析、黏度分析、核磁共振分析相结合的方法对其复配−交联改性机理进行分析。结果表明:(1)复配增效过程存在2种作用机制:首先瓜尔胶中无半乳糖分布的区域可与黄原胶分子产生氢键或范德华力嵌合形成三维网状结构以增黏;同时在瓜尔胶作用下黄原胶易发生自缔合以提升体系结构黏度。(2)有机硼中的硼酸根离子主要通过络合半乳糖上的羟基以发生交联反应,体系黏度得到进一步提升,其过程可分为起始期、过渡期、上升期、稳定期4个阶段,各阶段交联反应的快慢主要受有机配位体释放硼酸根离子的速度影响。研究成果为解决含煤地层垮塌难题提供新的解决方案,同时对植物胶冲洗液的改性研究具有一定的参考价值。

To improve the adverse effects of the depletion of plant gum resources on the application of flushing fluid in complex strata such as coal-bearing strata,a study was conducted on the compound and crosslinking modification of guar gum.A new type of plant gum flushing fluid(GXB)was developed using xanthan gum as the compound synergist and organic boron as the crosslinking modifier,with cross-linking control agent and inorganic treatment agent as the supplementary.Meanwhile,a series of performance evaluation was carried out.The evaluation results show that GXB has excellent performance and can meet the requirements of drilling in complex strata such as the coal-bearing strata.In addition,the mechanism of its compound-crosslinking modification was analyzed with the infrared spectrum analysis,viscosity analysis and nuclear magnetic resonance analysis in combination.The results show that:(1)There are two mechanisms of action in the process of compound synergism.Firstly,the galactose-free regions in guar gum could form hydrogen bonds with xanthan gum molecules or van der Waals forces to form a three-dimensional network structure to increase the viscosity.Secondly,the xanthan gum is prone to self-association under the action of guar gum to improve the structural viscosity of the system.(2)The viscosity of the system is further improved by the cross-linking reaction of borate ions in organic boron by complexing the hydroxyl group on galactose.The process can be divided into four stages:the initial stage,the transitional stage,the ascending stage and the stable stage.Besides,the speed of the cross-linking reaction in each stage is mainly affected by the release rate of borate ions by the organic ligand.Generally,the research results provide a new solution to solve the problem of coal-bearing strata collapse and have a certain reference value for the study on modification of plant gum flushing fluid.