Page 181 - Well Control for Completions and Interventions

Well Control Surface Equipment 173

Figure 4.26 Remote control blow out preventer panel.

4.9.7 Accumulator volume calculations
Accumulators must be sized in accordance with regulatory requirements.
The first step in calculating the volume of fluid available in a system is to
determine how much usable fluid each accumulator bottle can deliver.
Example: Using an 11 gallon, bladder-type accumulator bottle with a
1000 psi nitrogen, the precharge volume of usable fluid can be calculated
using Boyle’s law:
P 1 V 1 5 P 2 V 2 also P 1 V 1 5 P 3 V 3

where P 1 is the nitrogen precharge pressure of 1000 psi; P 2 is the mini-
mum operating pressure of 1200 psi; P 3 is the maximum operating pres-
sure of 3000 psi; V 1 bladder internal volume at precharge pressure (10
gallons); V 2 bladder internal volume at the minimum operating pressure,
P 2 (gallons); V 3 bladder internal volume at the maximum operating pres-
sure, P 3 (gallons).
Volume at minimum operating pressure, V 2 5 1000 3 10 5 8:33 galls.
1200
Volume at maximum operating pressure, V 3 5 1000 3 10 5 3:33 galls:
3000
The usable volume of hydraulic fluid in each bottle is 8.33 2 3.33 5
5 gallons.