调驱剂传输运移能力技术指标评价研究

Technical index evaluation of transport ability of profile control and displacement agents

近年来,化学驱油技术应用规模呈现逐年增加态势,但一些矿场试验效果却并不理想,造成这种状况的原因有许多,其中就包括调驱剂与储层孔隙适应性问题。针对矿场生产和理论实际需求,开展了化学调驱剂传输运移能力技术指标评价研究。结果表明,调驱剂在多孔介质中传输运移是实现深部液流转向作用的必要条件,传输运移能力可采用调驱剂注入结束时岩心前部与后部压差之比β值来评价,推荐技术指标范围:①β=1~3,优良;②β=4~8,中等;③β=9~15,较差;④β≥16,差。调驱剂滞留和传输运移能力与其自身材料分子结构形态即聚集体尺寸和岩心渗透率密切相关,二者的目的相互矛盾,实际应用时需要合理兼顾。黏度是流体内摩擦大小的评价指标,聚合物溶液内摩擦力大小与聚合物浓度、分子聚集体形态和溶剂水矿化度等因素有关。通过分子间物理缔合和化学交联反应可以改变聚合物分子聚集体形态(尺寸),进而达到增大聚合物溶液内摩擦力即增加黏度目的,但这将导致聚合物溶液传输运移能力变差,进而削弱聚合物溶液深部滞留和液流转向效果。

In recent years,the application scale of chemical flooding technology has been increased,but the results of some field tests are not ideal.There are many reasons for this situation,including the adaptability of profile control and displacement agent with reservoir pores.Aiming at the actual demand of field production and theory,the evaluation method and technical index of transport capacity of chemical profile control and flooding agent are studied.The results show that the transport capacity of profile control agent in porous media is a necessary condition for realizing the diversion of deep liquid flow.The transport capacity can be evaluated by the ratio of the pressure difference(β)between the front and the back of core at the end of injection of profile control agent.The recommended technical index ranges are as follows:①β=1~3,good transport capacity;②β=4~8,medium;③β=9~15,poor;④β>16,poor.The retention and transport ability of profile control and displacement agents are closely related to the molecular structure of materials,aggregate size and core permeability.Their purposes are contradictory and need to be taken into account reasonably in practical application.Viscosity is an index to evaluate the internal friction of fluids.The internal friction of polymer solution is related to polymer concentration,molecular aggregate morphology and salinity of solvent water.The size of polymer aggregates can be changed by intermolecular physical association and chemical cross-linking reaction,which can increase the friction force and viscosity of polymer solution,but this will also lead to poor transport capacity of polymer solution,and then weaken the deep retention and liquid flow diversion effect of polymer solution.