Challenging drilling operations in the Vaca Muerta unconventional shale gas play have prompted operators to implement innovative drilling techniques to improve drillability and operational efficiency. Significant benefits have been reported by utilizing Managed Pressure Drilling (MPD), Underbalanced Drilling (UBD), and/or drilling with casing; however, challenges still exist, due to a variety of reasons. The heterogeneity found from field to field and within fields has resulted in wells with significant events, some resulting in loss of the well, even on the same pad where a previous well has been drilled uneventfully.

Arguably, the most successful non-conventional drilling technique being incrementally used in the area is MPD, often combined with UBD, particularly in gas wells. As with any new technology implementation, there is a learning curve which can be accelerated by translating learnings from successful experiences.

Three key components for a successful implementation on MPD are still building a collective experience in the Vaca Muerta play. Firstly, the equipment and associated technology is the key enabler for physically perform the operations safely and efficiently.

The second component is a ‘soft’ framework consisting of a robust layered approach including overarching standard policies, the MPD strategy for implementation in the specific project, conceptual and detailed procedures, and specific work instructions.

Lastly, the human component is a group of competent personnel, whom, at their specific responsibility level, understand the ‘soft’ framework, and knows how to operate the hardware to implement the technology so that objectives are met.

The potential of the technology is limited to the weakest of these three components. A strong combination of any two of them, not complemented by the third one, will most likely result in a partial success at best, if not a complete failure at worst.

The operator had recently three major events in wells being drilled with MPD, which resulted in the loss of the wells. After implementing a training program on MPD/UBD, which emphasized the human factor and understanding of the equipment, the ‘soft’ framework of strategy, procedures and project management, the safety and efficiency during operations has increased significantly. This resulted in a better handling of events related to bottom hole pressure control without a single well loss event to the date of writing this document, approximately nine months of continuous operations. The other mainstay of this process has been the flexibility to adapt the application of the methodology based on the well challenges encountered.

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