What is Rod Pump Spacing?
Rod pump spacing is the distance between the seating nipple and the pump in a rod-pumped oil well. Correct spacing compensates for rod stretch under load and ensures the pump operates at full stroke efficiency. Improper spacing leads to reduced production or equipment damage.
How to Calculate Rod Pump Spacing
Here is the formula:
[\text{RPS} = \frac{9 \times \text{FL}}{1{,}000} + \frac{2 \times \text{SND}}{1{,}000}]
Where:
- RPS is the rod pump spacing (ft).
- FL is the fiberglass rod length (ft).
- SND is the seating nipple depth (ft).
The constants 9/1,000 and 2/1,000 are empirical factors for fiberglass rod stretch.
Calculation Example
A well uses 800 feet of fiberglass rods with a seating nipple depth of 10 feet.
Calculate the rod stretch component:
[\frac{9 \times 800}{1{,}000} = 7.2 \text{ ft}]
Calculate the nipple depth component:
[\frac{2 \times 10}{1{,}000} = 0.02 \text{ ft}]
Add the components:
[\text{RPS} = 7.2 + 0.02 = 7.22 \text{ ft}]
The rod pump spacing is 7.22 feet.