Additional costs caused by natural well ageing

Higher pumping costs at constant pumping rate

Pumping
rate Q		 Total
drawdown
stotal		 Drawdown increase Δ
s (compared with
ideal drawdown)		 Proportion
of total
drawdown
caused by well
ageing		 Additional
pumping
capacity
(calculated)		 Additional costs p.a.
(Pumping rate as
indicated & cost
of power supply
0.11 €/kWh)
[m³/h] [m³/s] [m] [m] [m³/h] [W] [€]
30 0,0083 3,88 3,88 1,88 220 211,99
45 0,0125 6,35 2,47 3,35 587 565,32
60 0,0167 10,26 3,91 6,26 1462 1408,78
70 0,0194 14,16 3,90 9,51 2591 2496,68

The additional drawdown exceeds 1,8 m at a discharge rate of 30 m3/h. At 40 m3/h it already increases to more than 3m, whereas at 70 m3/h as much as 9,5 m out of the total drawdown of 14,16 m can be assigned to entrance losses due to well ageing.

As the well ages, pore space diminishes and the amount of water which can enter the well decreases. Additional energy has to be supplied to overcome the entrance flow resistance in the gravel pack and in the screen slots. The incrustations grow exponentially and this inevitably leads to surging pumping costs.

The increased production costs due to well entrance losses due to ageing can be calculated anonymously in our interactive form.