Deepwater and high pressure wells, especially in Gulf of Mexico, are raising unprecedented challenges to Oil & Gas operating companies due to extremely high mechanical loads. The learnings from drilling operations and the evolution of regulations, pushed the development of more complex, slimmer, non-standard well designs.
This paper describes the Performance Baskets approach, a solution developed to meet those collapse needs that cannot be met using standard materials and conventional techniques for pipe performances calculation.
This methodology uses production's intrinsic variability by segregating the pipes into two baskets depending on their collapse performances: one contains the pipes with standard high collapse rating, and the other includes the enhanced design collapse rating.
The rating of each pipe is calculated to a target reliability level, using a proprietary model. The model accounts for mechanical properties and residual stresses, based on physical tests; and the geometry of each pipe, obtained by automated non-destructive inspection to 100% surface coverage. Pipe traceability assures the link between shop floor and data. Actual collapse tests confirm ratings and model assumptions.
The Performance Baskets methodology was initially applied to 5 different products included in the string design of one of the most challenging wells in the Chevron Deepwater Asset Class. The tubular items are: 13 5/8" 88.2#, 16.08" 109.90#, 16.15" 119.23#, 16.15" 126.91#, and 16.20" 131.70#. This methodology can actually be applied to the complete range of high collapse products available in the industry.
Thanks to this methodology, the enhanced design collapse rating was boosted beyond the standard published high collapse value associated to the pipe to enable the end user covering the worst case levels predicted for collapse.
This approach proposes an alternative methodology that has no precedents in the industry. Based on individual pipe performance calculation, it offers a cost-effective innovative solution to reach ultimate collapse properties to balance the cost of traditional Single Basket offers.
