弱碱三元体系对QD1区砾岩油藏储层伤害的实验研究
发布时间:2018-10-21 15:00
【摘要】:三元复合驱技术是当前国内化学驱中采收率较高的一种三次采油技术,该技术的应用在很大程度上延缓了油田产量递减的速度,给油田带来了良好的经济效益,现已成为不少油田采油技术的主要接替措施。不过,三元复合驱的应用同样会对储层造成不小的伤害,带来诸多问题。本文针对新疆油田QD1区砾岩储层特征,开展弱碱三元复合体系对砾岩油藏储层伤害的实验研究,具体工作如下:首先,本文结合QD1区砾岩储层的岩矿、流体等特征,分析了弱碱三元复合体系对储层的潜在损害,并对其损害机理进行了综述。其次,利用化学滴定的方法以及激光粒度仪等仪器,分别研究了弱碱碳酸钠体系、弱碱三元复合体系与地层流体的配伍性,考察了碳酸盐垢生成规律。随后,本文又从黏土膨胀规律、硅质垢形成规律、砾岩岩屑的静态溶蚀三个方面研究弱碱三元体系与储层的配伍性。考察了黏土矿物在弱碱碳酸钠体系、二元复合体系以及三元复合体系中的膨胀规律;硅质垢在不同pH值条件下的生成规律以及碳酸钠、表面活性剂、聚合物对其影响;同时考察了砾岩岩屑在不同浓度碳酸钠体系、弱碱三元复合体系中的溶蚀规律。最后,研究了弱碱碳酸钠体系、二元体系以及三元体系对砾岩岩芯的动态溶蚀作用。实验结果表明:碳酸盐垢、碱对岩石骨架以及黏土矿物的溶蚀导致微粒运移、黏土膨胀以及高分子聚合物的吸附滞留等均是弱碱三元复合体系对储层的潜在物理、化学伤害;聚合物和表面活性剂能够对碳酸盐垢的形成起到一定抑制作用,三元体系中形成的碳酸盐垢粒径要比弱碱碳酸钠体系中小一个数量级;黏土膨胀规律受碱液浓度、聚合物和表面活性剂影响,三者均在一定程度上促进黏土膨胀;硅酸根聚合成垢受pH值影响较大,随pH值降低硅酸根聚合趋势越来越严重,而聚合物和表面活性剂能够在一定程度上抑制硅垢的形成,抑制程度约为10%~45%;静态溶蚀结果表明,三元体系中消耗的碳酸根离子以及溶蚀出的硅铝离子浓度均比单一碱体系小,说明聚合物和表面活性剂能够抑制碱对地层的伤害,同时结果还表明近井地带岩石受到的溶蚀较为严重,溶蚀出的硅离子具有成垢的趋势;动态溶蚀结果表明,碱浓度越大,对岩芯的伤害越大,并且高渗岩芯的伤害程度要小于低渗岩芯,伤害的主要方式是碱对岩石溶蚀造成岩石或者黏土颗粒脱落、运移以及碳酸盐垢沉淀,聚合物和表面活性剂吸附在岩石表面减缓碱的溶蚀。本文研究了弱碱三元复合体系对砾岩储层的伤害规律,对油田的三元复合应用具有一定的理论指导作用。
[Abstract]:ASP flooding is a high recovery technology in chemical flooding in China at present. The application of this technology to a large extent slows down the rate of oil production decline and brings good economic benefits to the oil field. Now it has become the main replacement measure of oil recovery technology in many oilfields. However, the application of ASP flooding will also cause serious damage to reservoir and bring many problems. According to the characteristics of conglomerate reservoir in QD1 area of Xinjiang Oilfield, this paper carries out an experimental study on the damage to conglomerate reservoir by weak alkali ternary composite system. The specific work is as follows: firstly, this paper combines the characteristics of rock, mineral and fluid of conglomerate reservoir in QD1 area. The potential damage of weak alkali ternary system to reservoir is analyzed and its damage mechanism is summarized. Secondly, by means of chemical titration and laser granulometer, the compatibility of weak base sodium carbonate system, weak base ternary composite system and formation fluid was studied, and the formation law of carbonate scale was investigated. Then, the compatibility of weak alkali ternary system with reservoir is studied from three aspects: clay expansion rule, siliceous scale formation law and static dissolution of conglomerate cuttings. The expansion law of clay minerals in weak base sodium carbonate system, binary composite system and ternary composite system, the formation of siliceous scale under different pH values and the effects of sodium carbonate, surfactant and polymer on it were investigated. At the same time, the dissolution law of conglomerate cuttings in different concentration of sodium carbonate system and weak alkali ternary composite system was investigated. Finally, the dynamic dissolution of conglomerate core by weak base sodium carbonate system, binary system and ternary system is studied. The experimental results show that carbonate scale, alkali dissolution of rock skeleton and clay minerals lead to particle migration, clay expansion and adsorption and retention of polymer are all potential physical and chemical damage of weak alkali ternary system to reservoir; The formation of carbonate scale can be inhibited by polymer and surfactant. The particle size of carbonate scale formed in ternary system is one order of magnitude smaller than that in weak base sodium carbonate system. The effects of polymer and surfactant on clay expansion were improved to a certain extent, and the formation of scale by silicic acid polymerization was greatly affected by pH value, and the trend of silicic acid polymerization became more and more serious with the decrease of pH value. However, polymer and surfactant can inhibit the formation of silicon scale to a certain extent, and the inhibition degree is about 1045%. The concentration of carbonate ion consumed in ternary system and the concentration of dissolved Si-Al ion in ternary system are smaller than that in single base system, which indicates that polymer and surfactant can inhibit the formation damage caused by alkali. At the same time, the results also show that the dissolution of rocks in the near well area is more serious, and the corrosion of silicon ions has the tendency of scaling, and the dynamic dissolution results show that the more alkali concentration, the greater the damage to the core. And the damage degree of high permeability core is smaller than that of low permeability core. The main way of damage is rock or clay particles falling off, migration and carbonate scale precipitation caused by alkali dissolution of rock. The polymer and surfactant adsorbed on the rock surface to slow down the dissolution of alkali. In this paper, the damage law of weak alkali ternary composite system to conglomerate reservoir is studied, which can be used to guide the application of ternary composite in oil field.
【学位授予单位】:西南石油大学
【学位级别】:硕士
【学位授予年份】:2016
【分类号】:TE357.4
[Abstract]:ASP flooding is a high recovery technology in chemical flooding in China at present. The application of this technology to a large extent slows down the rate of oil production decline and brings good economic benefits to the oil field. Now it has become the main replacement measure of oil recovery technology in many oilfields. However, the application of ASP flooding will also cause serious damage to reservoir and bring many problems. According to the characteristics of conglomerate reservoir in QD1 area of Xinjiang Oilfield, this paper carries out an experimental study on the damage to conglomerate reservoir by weak alkali ternary composite system. The specific work is as follows: firstly, this paper combines the characteristics of rock, mineral and fluid of conglomerate reservoir in QD1 area. The potential damage of weak alkali ternary system to reservoir is analyzed and its damage mechanism is summarized. Secondly, by means of chemical titration and laser granulometer, the compatibility of weak base sodium carbonate system, weak base ternary composite system and formation fluid was studied, and the formation law of carbonate scale was investigated. Then, the compatibility of weak alkali ternary system with reservoir is studied from three aspects: clay expansion rule, siliceous scale formation law and static dissolution of conglomerate cuttings. The expansion law of clay minerals in weak base sodium carbonate system, binary composite system and ternary composite system, the formation of siliceous scale under different pH values and the effects of sodium carbonate, surfactant and polymer on it were investigated. At the same time, the dissolution law of conglomerate cuttings in different concentration of sodium carbonate system and weak alkali ternary composite system was investigated. Finally, the dynamic dissolution of conglomerate core by weak base sodium carbonate system, binary system and ternary system is studied. The experimental results show that carbonate scale, alkali dissolution of rock skeleton and clay minerals lead to particle migration, clay expansion and adsorption and retention of polymer are all potential physical and chemical damage of weak alkali ternary system to reservoir; The formation of carbonate scale can be inhibited by polymer and surfactant. The particle size of carbonate scale formed in ternary system is one order of magnitude smaller than that in weak base sodium carbonate system. The effects of polymer and surfactant on clay expansion were improved to a certain extent, and the formation of scale by silicic acid polymerization was greatly affected by pH value, and the trend of silicic acid polymerization became more and more serious with the decrease of pH value. However, polymer and surfactant can inhibit the formation of silicon scale to a certain extent, and the inhibition degree is about 1045%. The concentration of carbonate ion consumed in ternary system and the concentration of dissolved Si-Al ion in ternary system are smaller than that in single base system, which indicates that polymer and surfactant can inhibit the formation damage caused by alkali. At the same time, the results also show that the dissolution of rocks in the near well area is more serious, and the corrosion of silicon ions has the tendency of scaling, and the dynamic dissolution results show that the more alkali concentration, the greater the damage to the core. And the damage degree of high permeability core is smaller than that of low permeability core. The main way of damage is rock or clay particles falling off, migration and carbonate scale precipitation caused by alkali dissolution of rock. The polymer and surfactant adsorbed on the rock surface to slow down the dissolution of alkali. In this paper, the damage law of weak alkali ternary composite system to conglomerate reservoir is studied, which can be used to guide the application of ternary composite in oil field.
【学位授予单位】:西南石油大学
【学位级别】:硕士
【学位授予年份】:2016
【分类号】:TE357.4
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