Real-time Completion Monitoring with Acoustic Waves

Deepwater production is challenged by well underperformance issues that are hard to diagnose early on and expensive to deal with later. Problems are amplified by reliance on few complex wells with sand control media. New downhole data is required for better understanding and prevention of completion and formation damage. We introduce Real-Time Completion Monitoring, new non-intrusive surveillance method for identifying impairment in sand-screened completions that utilizes acoustic signals sent via the fluid column. These signals are carried by tube waves that move borehole fluid back and forth radially across the completion layers. Such tube waves are capable of "instant" testing of presence or absence of fluid communication across the completion and are sensitive to changes occurring in sand screens, gravel sand, perforations, and reservoir. The part of completion that has different impairment from its neighbors will carry tube waves with modified signatures (velocity, attenuation) and also would produce reflection from the boundary where impairment changes. The method would rely on permanent acoustic sensors performing acoustic soundings at the start of production and then repeating these measurements during the life of well. Thus, it could be thought of as "miniaturized" 4D seismic and "permanent log" in individual wellbore.