Future Engineering Journal


Ilmenite is often used as a weighting agent in drilling fluids to increase the fluid density, but the formation of a filter cake on the borehole wall can impact cementing operations and reduce well productivity. To remove the filter cake, various techniques can be employed such as chemical treatments, mechanical methods, or a combination of both. The goal of this study is to evaluate the effectiveness of chemical removal of ilmenite-based filter cake using 7.5 wt.% hydrochloric acid (HCl) and hydroxyethyl ethylenediamine triacetic acid (HEDTA) – chelating agent. The filter cakes were generated using API filter press under harsh conditions of 300 psi pressure and 250°F temperature. Sandstone cores (2.5-in. diameter and 1-in. thickness) were utilized to replicate the formation during filtration experiments. The filtrate fluid was collected and the sandstone cores with filter cakes were scanned using computerized tomography (CT) technology. Immediately after that, the cores and filter cakes were soaked with HCl–HEDTA solution for 6 hours, followed by CT-scanning the cores and remaining filter cakes again. After acidizing, the effluent solution was analyzed using inductively coupled plasma (ICP). Scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS) was used to analyze the dried filter cakes and remaining residue. The results showed that, the use of 7.5 wt.% HCl was effective in partially removing the ilmenite-based filter cake. Additionally, the use of HEDTA showed limited effect on the efficiency of filter cake removal, but it effectively prevented corrosion problems during the treatment. This study presents useful findings on removing ilmenite-based filter cake with a low acid concentration and reducing the risk of corrosion issues.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.