Modeling Expertise Takes Uncertainty out of Multi-Zone BaSO4 Scale Squeeze LifetimesMaximize excellence in practice
A customer operating in the North Sea had numerous wells with water production from multiple production zones. While the zones all have similar porosity and permeability, pressure differences caused production heterogeneity from the zones. Produced water has high barium content and is prone to aggressive scaling. Scale squeezes are a preferred method to control barite deposition in the perforated interval and had been used successfully in this field. However, zonal heterogeneity meant squeeze placement was non-uniform, resulting in different squeeze lifetimes for each zone. This led to the risk of having some producing zones fall below the minimum inhibitor concentration (MIC) despite surface tests showing returns remaining above the MIC. The customer sought help from Baker Hughes to determine appropriate scale squeeze treatment schedules that would ensure all zones remain at or above the MIC.
Baker Hughes personnel worked closely with the customer to carry out a squeeze modeling study. The most challenging well in the field was selected for initial work. The well produced from a sandstone reservoir with low clay content, and had an average porosity of 30% and average permeability of 3 darcy. The well featured a 1429 foot horizontal interval producing over 12,500 BWPD from 9 zones. By simple calculation, to ensure a 1 year squeeze treatment life, in excess of 4.5 million barrels of water would need to be protected.
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