Parametric Analysis of and Design Recommendations for a Conductive Chamber Used for Acid-Etched Fracture Conductivity Testing

Acid-etched fracture conductivity testing (AFCT) is a key technique for evaluating the effectiveness of acid fracturing, but the existing test apparatus still presents many problems. One of these problems is the sudden expansion at the connection part, which leads to flow instabilities. To address the limitations of the current experimental apparatus, a new structure for the conductive chamber was developed. By using computational fluid dynamics methods, a numerical model of the fluid domain, was established. A numerical parameter sensitivity analysis was subsequently conducted, with the diverging angle ranging from 12° to 22°, the buffering section length ranging from 10 to 35 mm, and the inner diameter of the injecting pipe ranging from 2 to 7 mm. Considering factors such as the fluid flow characteristics, material costs, and processing costs, the recommended structural parameters for the conductive chamber were determined as follows: a diverging angle of 16°, a buffering section length of 30 mm, and an injecting pipe inner diameter of 5 mm. A simple preliminary experimental comparison between the existing and new structures was conducted; the experimental results primarily show a more uniform etching pattern when using the new structure under simulated conditions. This study provides a scientific basis for upgrading and improving AFCT apparatus. The new geometry may reduce hydraulic interference and potentially improve test reliability.