低矿化度水驱提高原油采收率的机理分析及研究进展

Mechanism Analysis and Research Progress on Low Salinity Water Flooding

低矿化度水驱是指向油藏注入TDS介于1000~5000mg/L之间的水来提高采收率的方法。低矿化度水驱的机理比较复杂,通过研究经典文献、分析实验结果、总结对比矿场试验效果,发现低矿化度水驱提高原油采收率是多种因素共同作用的结果,主要机理有黏土颗粒运移、润湿反转、类碱驱机理、多价离子交换、双电层效应等。不同类型的油藏对低矿化度水驱具有不同的适应性,储层岩石性质、原油性质及地下水性质对低矿化度水驱的成功实施具有决定性作用。低矿化度水驱存在多种作用机理,而不同机理会在特定条件下发挥作用。其中,润湿反转的影响最为重要,它可以用来解释多种离子的影响。在合适的条件下,低矿化度水驱可以取得明显的降水增油效果。低矿化度水驱不需要使用化学药剂,不需要大量的能源供应,并且成本较为低廉、实施工艺相对简单、对环境的污染小,因此在陆地油田或海上油田均有着较为广阔的应用前景。

Low salinity water flooding is a method for EOR through the injection of water with 1000-5000 mg/L of total dissolved solids(TDS).Its mechanism is relatively complicated.Research of classic litera-tures,analysis of experimental results and compare of field test results show that EOR by the low salinity water flooding is the result of a combination of factors.The main mechanisms are the migration of clay parti-cles,wettability alteration,alkali-like flooding mechanism,multivalent ion exchange,electric double layer effect,etc.Different types of oil reservoirs have different adaptability to the low salinity water flooding.The properties of rock,crude oil and groundwater are decisive for the successful implementation of the low salinity water flooding.The mechanisms of the low salinity water flooding are various and each of them may pay the role on the specific conditions.Among them,the wettability alteration has the greatest influence and it can be explained the impact of various kinds of ions.Under suitable conditions,the low salinity water flooding can obtain significant oil recovery.Chemical agents and a large amount of energy supply do not need for the low salinity water flooding.Due to the low cost,relatively simple implementation process and low environmental pollution,the low salinity water flooding has wide application prospects in land or offshore oilfields.