## ESP design – Step 4: Total Dynamic Head

The step4 of the ESP design consists on determining the total dynamic head required to pump the desired capacity. It is common to simplify the procedure by combining or summarizing the additional energy that the pump must supply into a single term, Total Dynamic Head (TDH). TDH is a summation of the net vertical distance ﬂuid must be lifted from an operating ﬂuid level in the well, the frictional pressure drop in the tubing and the desired wellhead pressure.

TDH = HD + HF + HT

• TDH: total dynamic head in feet (meters) delivered by the pump when pumping the desired volume.
• HD: vertical distance in feet (meters) between the wellhead and the estimated producing fluid level at the expected capacity.
• HF: the head required to overcome friction loss in tubing measured in feet (meters).
• HT: the head required to overcome friction loss in the surface pipe, valves, and fittings, and to overcome elevation changes between wellhead and tank battery.

PS: HT is normally measured in gauge pressure at the wellhead. It can be converted to head, in feet (meters) as follows: HT = (psi / (0.433 psi/ft x sp. gr.)

## Total Dynamic Head Calculation

In this article “ Total Dynamic Head Calculation ”, the concept of the dynamic head is further detailed. As discussed in the previous article titled: “Total Dynamic Head (TDH)”, TDH is the sum of three basic components:

1. Net Vertical Lift (NL) = is the net distance where the fluid must be lifted,
2. Tubing Friction Loss (TFL) = Flow disturbance in the tubing string during pumping process,
3. Tubing Head Pressure (THP) = Pressure which the unit must pump against (back pressure caused by choking on well head).

## Total Dynamic Head (TDH)

To properly select the pump, well performance must be estimated. Fundamentally, well performance estimates deﬁne what additional energy (i.e., volumetric ﬂow rate and differential pressure or head) must be supplied by the pump to deliver a desired stock tank ﬂow rate (API RP11 S4).

It is common to simplify the procedure by combining or summarizing the additional energy that the pump must supply into a single term, Total Dynamic Head (TDH). TDH is a summation of the net vertical distance ﬂuid must be lifted from an operating ﬂuid level in the well, the frictional pressure drop in the tubing and the desired wellhead pressure.

TDH = HD + HF + HT