The CSG Sustainment phase needs to deliver an average of 300 new coal seam gas (CSG) wells per year over the operating life of the project, at significantly less cost per well than the first 1,000 wells completed in the Development phase. One area identified for improvement was the process used to construct, complete and tie-in the new wells to the existing gas and water gathering infrastructure; one of the most complex aspects of the entire upstream project.
The challenge was to create a “right-sized” process that could support the well delivery rate and costs whilst maintaining safety, technical and quality standards. The revised process needed to be developed and implemented over an 8-10 week timeframe.
Nova Systems (Nova) was engaged to apply its Gas Field Facilities completions and handover experience, in concert with our systems engineering problem-solving skills, to the wells and gathering problem. This began by challenging those areas of the existing process that contributed most of the inefficiency – the “sacred cows”. From this work two key principles were identified to drive the new process:
- Adopt a manufacturing-style acceptance process that leverages the repeatable nature of CSG wells rather than asset-by-asset acceptance; and,
- Change to a system-based field expansion method (well clusters) that delivers the fastest gas-to-plant process path, rather than the ad-hoc geographical method based on land access.
With these principles agreed by the key client stakeholders the existing Wells & Gathering completions process was drawn up showing the flow of activities from early network design, through Construction to Commissioning and Handover. An optimised process was drawn up for comparison based on Nova’s own experience in CSG development, and the key principles established. As with any complex problem solution, the revised process was iterated a number of times based on consultation with field staff to account for limitations in available tools, support contracts and field infrastructure.
The final agreed Wells & Gathering Completions, Commissioning and Handover procedure was approved by the Engineering Authority and became part of the FY2015/16 Field Development Plan. The process has reduced the CSG well delivery cost by approximately 5%. Just as importantly, the systematic expansion of fields by well clusters has minimised the lost opportunity cost associated with stranded wells.
Systemising the field and clearly defining the system boundaries must be the first step in any CSG field expansion. This activity needs to engage all teams involved in the delivery of new wells. Once established these systems should drive all subsequent activities – land access, drilling, design, construction and commissioning. Each team must work collaboratively to deliver a common system into operation. Small efficiencies gained in each step can lead to significant savings when aggregated across hundreds of wells.