Project Background

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The Xanab field is of great interest in the Integral of production block AS02-04 by the volume of reserves and production that can offer in the short, medium and long term. The installation of the 20"Ø x 5.877km oil and gas pipeline from Xanab-C to Xanab-D is of great importance in the strategy of Pemex exploration and production to increase the management and transport of hydrocarbons of the XANAB field.

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Problem Definition​

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Upheaval buckling (UHB) is a major design concern for a trenched and buried pipeline operating at high temperature and pressure. Imperfections out-of-roundness (OOS) are naturally formed at the bottom trench profiles during post installation trenching activities. For buried pipeline conditions, expansion is restrained by the frictional resistance of the soil and causes the pipeline to be in compression, coupled with imperfection OOS curvature, the pipeline will tend to buckle upwards to relieve these forces and causing major overstress failure. 

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Scope of the Studies:

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DASH7 was involved the design and engineering to mitigate the upheaval buckling caused by trenching OOS imperfection. The studies involved:-

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• Prediction UHB analysis to OTC 6335 & DNV-GL-F110.

• Minimum Backfill cover design.

• Post installation out-of-straightness analysis.

• UHB mitigation design – rock dump download design.