A Sulfur Plugging Experiment in the Presence of Ferric Ion.

Acid fracturing is widely used as an effective reconstruction measure in sour gas reservoirs, but sulfur and ferrous sulfide plugging are still problems in reservoir secondary damage. In order to simulate reservoir damage in the presence of ferric ion in residual acid, an artificial core with ferric ion and supersaturated natural sour gas was adopted as a sample. A depletion-type damage experiment was carried out to observe sulfur precipitation and plugging in the core. The results show that core color became dark and weight was increased. Permeability decreased with increased time and the decreasing trend was steep at the beginning and then down to smooth rate slowly. Trace pyrite was discovered using X-diffraction. Severe damage was formed by sulfur deposition in the presence of ferric ion. [ABSTRACT FROM AUTHOR]