In order to select the most suitable pump, Refer to the pump selection data table in the manufacturer’s catalog for pump type, range and pump performance curve. Based on expected fluid production rate and casing size, select the pump type which will be operating within the recommended operating range and nearest to the pump’s peak efficiency.
When two or more pump types have similar efficiencies at the desired production rate, the following recommendations should be considered to select the most adaptable pump to the well conditions:
The shape of the pump performance curve:
The ability of a pump to adapt to changes in well performance depends on the characteristic shape of the pump performance curve. A pump with a steep characteristic (i.e. large change in head with respect to flow rate) is less suited to a well with poorly defined inflow performance (IPR), especially if it is intended to produce with a fixed drawdown. For such pumps, a small loss in IPR translates to a large fall in pump intake pressure and may result in gas locking. Conversely, the head produced by a pump with a flatter characteristic will change less for a given change of flow rate and can therefore be used over a wider variety of IPR’s with limited changes in intake pressure.
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.)
As described in the previous article ESP nine step design procedure, Centrilift has established a nine-step procedure to design the appropriate electrical submersible pump. The first step of this ESP design procedure, and certainly the most important step, consists on collecting the basic data. This is the most important step because all the others design steps will depend on the basic data selected in step 1. If the basic data quality is good the design will be good and the ESP will operate at its optimum conditions. Otherwise, if the input data quality is poor the design will usually be marginal.
Centrilift has established a nine-step procedure to design the appropriate electrical submersible pump in order to have an efficient and cost-effective performance. This article gives an overview of the ESP nine step design procedure and outlines the procedure as a manual process to illustrate the design steps. Each of the nine steps will be explained in detail in the next articles.
Specific examples will be worked through in each step of the ESP design.
This nine step procedure is a basic hand-design of simple water and light crude oil. For more complicated well conditions, such as high GOR, viscous oil, high-temperature wells, there are many of available ESP design software (e.g. Prosper software – Product of Petroleum Expert; Pipesim software – Product of Schlumberger; Autograph PC software – Product of Baker Hughes; Solution Sizing Software – Product of General Electric; DesignRite Software – Product of Schlumberger). The fashion of use of each of these ESP design software will be presented and explained in detail in upcoming articles in our website.