Wells with electric submersible pumps (ESPs) installed are sometimes allowed to produce naturally under certain circumstances such as when the ESP fails. The paths of natural production can be through the ESP stages, an auto flow valve (AFV) or through the bypass section of a Y-tool if installed. To understand the effect of different natural production scenarios on the flowing bottom hole pressure and the maximum achievable flowrate, a comprehensive sensitivity analysis is conducted.

In this study, hydraulic calculations are carried out to determine the frictional pressure losses through ESP pump stages and the Y-tool bypass section. Results are compared with AFV pressure drop, published in the literature. The effect of ESP size and oil density will be investigated. It is assumed that the number of ESP stages, wall roughness for ESP housings, casing and Y-tool, lengths of the ESP and the bypass section, and viscosity will be constant. It is also assumed that the wellbore/reservoir fluids are solids-free.

Results will be discussed thoroughly in the paper. It is shown that for relatively low flow rates, naturally producing through any of the three options is comparable. As flow rate increases, the frictional pressure losses increase, especially through the pump stages. Results also indicate that as ESP stages become smaller, flow will encounter a relatively much higher pressure drop across the ESP stages.

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