砂岩储层酸化智能复合酸液体系研究及应用

常规砂岩酸化为了实现有效解堵，必须采用前置液、处理液和后置液多段液体，其作业程序复杂，研制出一套智能复合酸液体系InteAcid。该酸液能替代常规砂岩酸化的多段酸液，实现单步酸化，显著简化作业程序，特别适合于海上酸化作业。室内实验表明，InteAcid 在溶解砂岩矿物和解除伤害的同时，能有效抑制二次沉淀，对金属氟化物、氟硅/铝酸盐和金属氢氧化物沉淀抑制率可分别达到71.81%、70.51% 和78.59%；单步岩芯流动实验后，无伤害、轻微伤害、重度伤害岩芯渗透率提高为原始渗透率的1.35 倍、3.60 倍和15.00 倍；酸处理后孔隙结构微观分析表明，该酸液具有提高岩芯渗透率和稳定黏土作用，对岩石骨架破坏很小。该酸液现场单步酸化11 口注水井，成功率100%，效果显著率达90%。

Study and Application of Intelligent Integrated Acid System for#br#Sandstone Stimulation

By use of preflush，treating fluid，over-flush and diverter，conventional sandstone acidizing treatment could effectivelybreak down formation and prevent the secondary precipitation，which is very complicated. To overcome the shortage ofconventional sandstone acidizing，InteAcid is developed. Through the use of InteAcid，single-step acidizing can be realized，instead of using conventional sandstone acidizing. Single-step acidizing could significantly simplify the acidizing stimulationprocess，which can be widely used for offshore well acidizing. The experimental data shows that InteAcid could not onlydissolve sandstone mineral and remove well damage effectively，but also prevent secondary precipitation excellently，especiallyfor metal fluoride precipitation（the inhibition ratio is 71.81%），fluosilicate/aluminate precipitation（the inhibition ratio is70.51%）and metal hydroxides（the inhibition ratio is 78.59%）. After treated by single-step acidizing，the original permeabilityof non-damage core，slight-damage core and severe-damage core have been improved to 1.35times，3.6 times and 15 timesrespectively. The micro pore structure analysis result shows that InteAcid can stabilize clay and almost never damage the rockstructure while improving the core permeability. 11 in-situ injection well have been stimulated by single-step acidizing. Thesuccess rate is 100% and 90 percent of these wells have been improved obviously，of which the injection index is increasedlargely and the pressure declines notably.