Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

9th Curtin University of Technology Science and Engineering International Conference 2014

自然科学;工业技术

Shafiq, Mian Umer^1 ; Mahmud, Hisham Khaled Ben^1 ; Hamid, Mohamed Ali^1

Petroleum Engineering Department, Curtin University, Sarawak, Malaysia^1

关键词: Comparative studies;    Formation permeability;    Laboratory investigations;    Matrix acidizing;    Permeability and porosities;    Sandstone acidizing;    Sandstone formations;    Silica particles;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/78/1/012008/pdf
DOI  :  10.1088/1757-899X/78/1/012008

来源: IOP

【 摘 要 】

The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H3PO4and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid.