环保型无机沉淀转向剂性能特点及调驱能力研究

Research on characteristics and modification performance of environmental-friendly inorganic precipitating diversion agent

为了实现海上油田环保高效水驱开发,满足深部液流转向技术需求,开展了环保型无机沉淀体系性能及其影响因素实验研究。结果表明,硅酸钠溶液与渤海油田高矿化度区块注入水中的钙镁离子自发反应,生成沉淀悬浮体起到液流转向作用。从沉淀物生成量、药剂费用和矿场注入工艺等考虑,推荐浓度为0.02~0.05 mol/L,采取交替注入方式开展物模实验。结果表明,随着渗透率增加,封堵效果提高;随着钙镁离子和硅酸钠浓度增加,沉淀物生成量增加,封堵和调剖效果提高。微观可视化实验表明,体系在储层孔隙内一旦接触就会发生反应,生成沉淀物,使孔隙过流断面减小,渗流阻力增加,注入压力升高,中低渗透层吸液压差增大,吸液量增加,达到液流转向和扩大波及体积效果。在海上及其他作业空间受限的高矿化度油田有很大的应用推广价值。

In order to realize the environment-friendly and high efficient water drive development of off-shore oil field and meet the demand of deep fluid flow diversion technology,the research on the performance and influencing factors of the environment friendly inorganic precipitating diversion agent was developed.Results showed that the sodium silicate solution reacted spon taneously with the Ca2+and Mg2+of injected water in the high salinity block of Bohai oilfield,and the precipitated suspension from the reaction played a role of liquid flow diversion.Considering the factors of precipitation amount,cost of the agent and injection technology of mine area,the physical model experiment was carried out by alternating injection under the recommen ded concentration of 0.02~0.05 mol/L.The experimental results showed that the plugging effect increased with the increase of permeability.With the increase of concentration of Ca2+,Mg2+and sodium silicate,the amount of precipitates increased,and effects of plugging and profile control were improved.Microscopic visualization experiments showed that the system reacted once in contact with the pores of the reservoir,formed precipitates,reduced the cross-section of pore flow,increased the filtra tional resistance,the injection pressure and the pressure differences between the medium-low permeability zones,thus increa sed the amount of liquid absorption,reached the goal of deep fluid flow diversion and expanded sweep efficiency.This techno logy has great application and popularization value in off-shore and other high salinity oil fields with limited working space.