Review of Gas Gathering System Efficiency in Onshore Fields of Imo State

Gas gathering systems form the critical first link in the natural gas value chain, responsible for collecting wellhead gas and transporting it to processing facilities. This study reviews the operational efficiency of gas gathering systems deployed in onshore oil and gas fields in Imo State, focusing on facilities operated by indigenous exploration and production companies. The research adopts a descriptive analytical approach, utilising production data, equipment inspection records, and interviews with facility engineers to evaluate gathering system performance. Parameters assessed include compressor uptime, pipeline throughput efficiency, separator performance, and gas quality at the gathering points. The study examines common operational challenges including liquid loading in low-pressure wells, compressor mechanical failures, and hydrate formation in transmission lines during cold weather periods. It also investigates the effect of aged infrastructure on gathering efficiency, given that many of the surveyed facilities utilise equipment installed over three decades ago. Findings are expected to show that average gathering efficiency falls below 70 percent at several facilities, resulting in substantial unplanned gas flaring and production losses. Recommendations include phased equipment replacement, adoption of multiphase flow optimisation software, and mandatory gas gathering efficiency reporting to the NUPRC. This study provides a baseline for evaluating gathering system performance improvement in southeastern Nigeria's onshore gas sector. Keywords: gas gathering, system efficiency, onshore fields, Imo State, production optimisation.