Abstract

A pressure pulse, known as a water hammer, can occur immediately after water injection wells are shut-in for emergency or operational reasons. Large pressure pulses may cause wellbore integrity problems such as sand-face failure and sand production. We propose a new workflow to simulate water hammer events, the resulting wellbore failure and sand production in water injectors. Based on the results of this workflow, recommendations are made for wellbore design and shut-in protocols for water injection wells.

The results presented in this paper, for the first time, allow us to quantitatively understand the role of well shut-downs and subsequent water hammer pressures on sand production. The failure of unconsolidated sands near the wellbore is affected by water hammer events, their amplitude, period, and attenuation. If a water hammer event occurs during shut-in of water injectors, the extent of the sand failure becomes larger and the failure zone continues to propagate along the stress concentration direction. The simulation results clearly show which parameters are important and suggest changes to well operations such as proper shut-in protocols that help to minimize the possibility of sand production. The results also suggest ways in which injectors can be designed to minimize the impact of water hammer events.

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