The "Dynamic Kill" technique has been used to perform off-bottom kills of both, surface and underground blowouts. Usually these kills are designed under the assumption that no kill fluid falls below the injection depth into the upward flow of the formation fluid. If this conservative assumption indicates that the kill is possible to achieve, the operator can confidently proceed with the field operations. However in some cases, calculations under this assumption will indicate that the kill is not possible, discarding a valuable potential solution to the problem. Recently completed research on counter-current flow of kill fluid falling through formation fluid that is flowing upward is applied here to off-bottom blowout wells. This study presents a procedure for controlling off-bottom blowout wells. It relies on the accumulation of liquid kill fluid injected while the well continues to flow to increase bottom hole pressure and assist in killing the well. The method is based on:

  1. The critical velocity that prevents control fluid accumulation which can be predicted by a new adaptation of Turner's model of terminal velocity (based on the liquid droplet theory.) This new model considers the flow regime of the continuous phase when evaluating the drag coefficient and the angle of deviation from the vertical.

  2. The amount of liquid that flows countercurrent into and accumulates within the well, which can be predicted based on the concept of Zero Net Liquid Flow (ZNLF) holdup.

These two concepts are integrated in the dynamic kill procedure, which is based on system performance analysis to better predict the feasibility of an off-bottom dynamic kill. These concepts were validated with full-scale experiments in a 2787-foot deep research well.

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