Coal seam gas production: the operational and maintenance challenges

Abstract

Compared to conventional gas, coal seam gas (CSG) production introduces additional complexities in operation due to the remoteness, number and distribution of the producing wells, the quantity of associated water and the variability in characteristics of each well. The potential irregularity in gas production is further highlighted when integrating with relatively steady state downstream facilities such as LNG production and power generation. Margins are particularly sensitive to operating cost because of the remoteness and distributed nature of the producing assets. Cost effective and reliable production of gas to the flow tolerances needed downstream requires that operations management, ongoing field development, asset maintenance and regulatory compliance be systematic and highly integrated. Experience shows that for operations reliant on distributed and remote assets, including CSG, that the ratio of predictive/preventive to corrective maintenance correlates directly to surety of gas production, with little margin to compensate for less than required reliability or low maintenance productivity. For CSG production it is difficult to avoid significant lost production as a consequence of higher levels of unplanned asset downtime. The remoteness, number of assets and operating cost constraints simply makes it difficult to overcompensate for lower reliability. Corrective actions are significantly more expensive when compared with centrally located assets because of the heightened pressure to correct in the shortest possible time. Further, deterioration of the maintenance regime compounds the effect as the emerging backlog of critical issues reduces the ability of crews to keep up with the preventative maintenance programme. Achieving a reliable outcome in CSG operations is therefore more reliant on a robust operations and maintenance management arrangement that also effectively incorporates the ongoing discrete activities of drilling, well completions, start-up and abandonment. To achieve these outcomes operators must ensure: the early development of maintenance philosophies, systems and processes during the project phase that consider the frequency of field variations for life of asset; a well planned system start up, commissioning and transition into first production; and, a constant focus on efficient deployment of resources, fit for purpose reliability and maintenance routines, logistics support and sparing plans, use of appropriate remote monitoring technologies and an incorporated regulatory compliance management plan. In its presentation PSN will demonstrate, through case study examples from its operations supporting coal seam gas and gas production assets in the United States and distributed and remote assets for the Western Australian Water Corporation, the challenges and management focal points critical to effective CSG production. The case studies will demonstrate the benefits achieved by PSN’s operations and maintenance management approach in the following areas: operations and maintenance readiness; distributed asset management; managing field development and modifications; implementing high performance maintenance; environmental monitoring and compliance; resource utilisation models; and, workforce training and development