Downhole Production Profile
Quantitative estimation of inflow rates in each zone over time (years). Answering the question: What flows where and how much?
Zonal production may be estimated from flow transients that are either a consequence of naturally occurring changes or we may set a change on purpose. Typically transient phases may be after restarts and after step rate changes. The tracer release from a zone is modulated by the inflow in the same zone so that a transient signature (or shot) is formed. This could be exploited and with proper models the zonal contribution could be estimated.
Water breakthrough alarm
Long term monitoring (up to 10 years dormant + 1 year water marking). Answering the basic question: Where in the well has water broken through? This is a question of building baseline tracer levels over time and alarms are estimated from trend models.
Additional question: Can water production pr zone be quantitatively estimated? Models may be extended to answer this, especially for very high water cuts where fluid flow will be closer to single phase.
Clean-up verification/early test production
Short term monitoring (days). Answering the questions: Has the crude oil displaced all completion fluids and are all zones contributing? Main clean-up may be performed during the first 10-15 hours. These hours are dominated by chaotic multiphase flow behavior, mud cake breakdown and gradually drawdown buildup.
The hours following the chaotic first displacement phase may give data from which relative zonal contribution may be indicated and in some cases even quantified. Interpretations will improve significantly with better modeling.
Identify water channels/monitoring flooded reservoirs
Medium term monitoring (months). Answering the question: Where is unwanted water from channels entering the well and which parts of the well are water-flooded? Water from channels may enter after a few days/weeks. A typical tracer concentration baseline buildup should be performed and water breakthroughs are estimated from trend models. With flooded reservoirs the water will tend to enter from day one. No baseline can be built so this poses a special challenge to the interpretation models. Estimates will be qualitative indications of inflow locations and is that tracer systems around the circumference of the wellbore may be required.
Long term monitoring (years) of the integrity of the completion. Does it isolate the zones over time? Are shut-in zones leaking? Is flow from the reservoir behaving as expected?
Again this is a question of building baseline tracer levels (or below detectable levels) over time and deviations are estimated from trend models.