巨厚强非均质性砂岩储层酸化技术

Acidification of Thick Highly Inhomogeneous Sandstone

以最大程度解堵、最小程度对岩心破坏、最优化酸液置放为目标对巨厚强非均质性砂岩储层酸液体系和酸化工艺进行了探索。采用钻井液伤害实验与酸化解堵实验相结合、长岩心实验与短岩心实验相结合,宏观测试与微观分析相结合的思路。进行研究结果表明,对于泥质含量高、胶结疏松的储层可适当增加前置酸浓度(HCl浓度增加到15%),同时降低主体酸HF浓度(降低到1%)。岩心切片结合电镜扫描分析确定伤害深度和解堵半径,为用酸规模优化提供依据。对于巨厚的孔隙型储层,可以通过封隔器分隔+变密度射孔+转向酸的组合模式实现储层均匀改造,而对于裂缝发育段应该坚持"大排量、大液量、高泵压"的改造模式以实现储层深度解堵。

Acidification fluid formulation and acidification technology are studied for the best results in the acidification of thick highly inhomogeneous sandstones. It is concluded that for reservoir formations with high shale content and that are poorly cemented, the concentration of the prepad acids shall be reasonably higher(for instance, the concentration of HCl shall be increased to 15%), and the main acid(for acidification) HF shall have its concentration reduced to, for instance, 1%. Slabbed cores in combination with SEMcan be used to determine the damaging depths, providing clues for the amount of acids to be used in acidification. For thick porous reservoirs, a combination of packer, perforation with variable intensities and diverting acids can be used in reservoir reformation. For reservoir formations with developed fractures, high flowrate, large amount of fluid and high pump pressure together can be used in eliminating deep plugging of the reservoir.