Case Study: A shallow-water flow study

Overview

A Q-Marine survey over the Europa field in the Mississippi Canyon area of the Gulf of Mexico was used to establish the effectiveness of Q-Technology for shallow water-flow (SWF) studies. This case study compares the results of an SWF analysis using the Q-Marine data set and a legacy data set.

SWF sands have been observed in water depths ranging from 400 to 2500 m, and at depths between 250 and 1000 m below the mudline. These SWF sands are overpressured due to rapid sedimentation. Small changes in pressure at these relatively shallow depths of burial on virtually unconsolidated materials with high porosities and low effective stresses can lead to significant water flows. These water flows can cause formation collapse and massive sanding into a well. Independent estimates have concluded that occurrences of SWF have cost offshore operators more than $1 billion through lost time, casing and drill string damage, and in extreme cases, the loss of the hole.

WesternGeco 'reservoir quality' Q-Technology seismic data improve signal-to-noise ratio (S/N) and provide higher frequency content and smaller bin sizes. These improvements assist in producing more accurate interpretations and reservoir characterizations, including detection and avoidance of SWF sands, thereby eliminating costly rig

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