摘要
为改善低渗透砂岩油藏的酸化效果,在施工前需要进行合理的评价实验。通过流动实验评价了前置酸、主体酸用量对酸化效果的影响,并在此基础上采用X衍射、岩石薄片、扫描电镜等手段对流动物理模拟结果进行了分析,使宏观现象和微观机理得到了有效结合。研究表明:S3井区岩样中含有较高的碳酸盐矿物,平均含量为13%;前置酸在钙质砂岩酸化过程中具有非常重要的作用,当前置酸段塞不足时,土酸和钙质胶结物反应产生沉淀,影响酸化效果;前置酸足量时,酸化效果明显,岩石孔隙得到有效增大。结合研究结果精选酸液体系,在S3井区进行了4井次酸化施工,起到了良好的增产效果。精细酸化设计可避免酸化后渗透率不增反降的问题,同时建议矿场试验中选用适合储层特点的添加剂以提高酸化效果和成功率。该研究结果对类似油藏酸化设计具有指导意义。
In order to improve the acidizing performance in low-permeability sandstone reservoir,appropriate laboratory evaluation experiments are necessary before acidizing operation. The effects of pre-acid and subject-acid volumes on acidizing performance are evaluated by laboratory flow experiment. X-ray diffraction,core thin-section,SEM and other methods are also used to analyze the laboratory flow experiment result,which realize an effective combination between macro and micro mechanism. Research shows that the core samples from Wellblock S3 contain relatively high-content carbonate minerals with a average content of 13%. Pre acid plays a very important role in calcareous sandstone acidizing process. Precipitation will be produced from the reaction between mud acid and calcareous cement in case of insufficient pre- acid volume. Favorable acidizing performance can be gained and reservoir rock porosity can be significantly increased with sufficient pre-acid volume. Based on laboratory flow experiment test,the acid system is optimized and used for 4 well-times in Wellblock S3,which indicate favorable acidizing performances. Fine acidizing design could avoid permeability falling instead of rising after acidizing treatment. Appropriate additives that are suitable with reservoir are recommended to improve acidizing performance and success rate. This research could provide certain guidance for the acidizing design in similar reservoirs.
出处
《特种油气藏》
CAS
CSCD
北大核心
2016年第4期131-135,157-158,共5页
Special Oil & Gas Reservoirs
基金
中国石油天然气股份有限公司重大科技专项"辽河油田原油千万吨持续稳产关键技术研究"(2012E-30)
关键词
砂岩酸化
地层伤害
低渗透
土酸
X衍射
岩石薄片
扫描电镜
高碳酸盐岩
sandstone acidizing
formation damage
low-permeability
mud acid
X-ray diffraction
thin-section
SEM
high content of carbonate rock
