Well Pengtan 106 is an appraisal well located at the structural high in the southeastern part of the Zhongshen 103 Well Block, Penglai Structure, northern slope of the Central Sichuan Paleo-uplift in the Sichuan Basin, and falls within the first-class development area of the Pengtan 1 Well Block. Four months after commissioning, the well experienced a simultaneous decline in wellhead pressure and production rate, failing to meet expectations. Initial analysis suggested potential downhole plugging.
To address this, Southwest Oil & Gas Field Company closely monitored production dynamics and conducted a comprehensive plugging cause analysis by integrating geological characteristics, dynamic monitoring data, downhole tubing string conditions, and rapid pressure recovery after shut-in. This resolved issues such as formation plugging caused by organic additive accumulation in early acidizing fluids and wellbore blockage due to plugging material backflow, which constrained productivity.
Drawing on the successful plug removal case of Well Pengtan 1, the company scientifically determined the acidizing scale and selected a small-scale acidizing operation using 80 cubic meters of gelled acid to ensure effectiveness. The operation was meticulously organized with strict quality control over construction plan design and scientific scheduling. Key risk points were identified and mitigated step-by-step to ensure safe execution.
For the plug removal process, a “controlled acid injection rate + shut-in soaking” approach was adopted to enable effective wellbore flushing and thorough contact between acid and near-wellbore plugging materials, enhancing the treatment efficiency.
Post time: Mar-28-2025