A combination of multiple down hole gauges and dual density / tracer logs were utilized to quantitatively evaluate distribution of fluid and proppant across a long perforated interval separated in two lobes and to quantify the annular pack percentage across the entire completion interval during a deepwater frac pack treatment in GoM. It was important to evaluate the achievement of an effective fracture in both lobes and define the annular pack percentage across the entire completion interval to be able to produce the well to its potential.
This technique quantitatively evaluated the entire frac pack process and determined screen out events in separate lobes and annular pack efficiency. The analysis also defined the dynamics of the treatment fluid and proppant slurry movement during the frac pack pumping operation and their final placement.
Several expected as well as unexpected conclusions and observations were identified. In summary, the diagnosis indicated that higher percentage of treatment fluid and proppant was received by the upper sandstone lobe. The exact proppant concentration at lower lobe screen out was identified. A baseline pre-pack value was established, which allowed the annular pack percentage to be calculated across the entire interval. It also provided detailed information on the sequence of events during washout at the crossover tool. All of these allowed the operator to confidently maximize deliverability from the subject well, which is currently producing 110 MMcfd.
The results from this case history and the technique described should result in a step change in frac pack evaluation. Quantitative evaluation eliminates any doubts about the effectiveness of the annular pack and allows operators to produce their assets at maximum deliverability. Additionally, it assists future completion designs and type selection.