Page 262 - Petroleum and Gas Field Processing

Design the necessary disposal facility to handle the treated produced
water and deck drain. Assume a water viscosity of 1.1 cP and a difference
in specific gravity of 0.2.

Solution
The first step is to calculate the total amount of water to be disposed of:
in: 1 ft 2 h
Rainwater ¼1:5 3000 ft 24
h 12 in: day
1 bbl
3 ¼ 1604 BPD
5:61 ft
min 1 bbl
Washdown water ¼ 50 gpm ð60 24Þ
day 48 gal
¼ 1500 BPD
Because the rainwater rate is larger than the washdown rate, it will be
considered in the design. Therefore,
Q w ¼ 4500 þ 1604 ¼ 6104 BPD
We first check the simplest disposal device (i.e., the disposal pile).
Using Eq. (33) with d m ¼ 150 mm,

2 ð6691Þð6104Þð1:1Þ
D ¼ 2 ¼ 9983:57
0:2ð150Þ
D ¼ 99:9in:
This is too large. Therefore, we check the skim pile. Using Eq. (39),
2 2
D L b ¼ð19:1Þð6104Þ¼ 116,586 in: ft
Assume various values for D and calculate the corresponding values of L b :

D(in.) 36 42 48
L b (ft) 89.9 66.1 50.6

Therefore, we can use a 48- in.-diameter pile with a 50- ft baffle section.
The total submerged length is, therefore Eq. (36),
L ¼ Lb þ 15
or
L ¼ 50 þ 15 ¼ 65 ft
which is greater than the minimum required length of 50 ft.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.