Odds and Ends, Archive 1
Units
This page is intended to be a dynamic page dedicated to 'stream-of-consciousness' thoughts and musings that may or may not be relevant to environmental issues in the oil and gas industry. Initially we focus on units - the source of a significant fraction of technical mistakes and errors in spite of our chemistry teachers' best efforts.
In the oil and gas industry commonly used units include barrels, SCF, MSCF, MMSCF, g/BHP-hr, lb-moles, and MMBTU/hr. Confusion often arises when databases spit out columns of numbers without units - are those MSCF or MMSCF? Barrels or Mgal? My advice - ask the 'stupid' question. It's better to ask than to be off by a factor of 1000.
The following is a list of numbers without units that are useful conversion factors in the oil and gas industry. See if you can recall the units for each and check yourself at the link found at the bottom of this page.
1.) 7.481
2.) 379.7
3.) 55
4.) 42
5.) 0.7302
In spite of computer and calculator technology, I still do most of my conversions manually (with unit justification). Temperature conversions are particularly cumbersome as the commonly used scales use different increments and alignments. The conventional conversion equations are confusing and hard to remember (is that +32 or -32... included or excluded from the parentheses?). I prefer the following versions:
These versions are simpler for me to remember. Regardless of which conversion I'm doing, the sequence is the same - add 40, multiply by the increment factor, subtract 40. Just remember that each Celsius degree is almost 2 Fahrenheit degrees, so when converting TO Fahrenheit use the factor almost equal to TWO.
The Mother of All Word Problems Involving Units
Finally, for your consideration - a word problem for you or your high school science student -
King Arthur decides his vacation home in Northumberland requires a moat, so he orders the local serfs to build one – a circular moat 2 furlongs in diameter (outside), 2 rods in bank-to-bank width, with vertical walls 5 yards from the bottom of the moat to the top of the overflow weir.
After months of weather-related delays and a couple of re-builds, the structure finally meets minimum project specifications and passes inspection. King Arthur then asks 28-year old Merlin to fill the moat with sanctified water from Gaelic Queen Nairne’s ‘private reserve’ spring at Caerlaverock Castle near Dumfries. It takes Merlin a fortnight and a quarter to make the round trip across the Cheviot Hills to Caerlaverock Castle and back; and he takes another day and a half to take care of chores and rest up his team of oxen in Northumberland before embarking on another trip. The capacity of Merlin’s haul wagon is 75 stone-moles of water, but spillage and evaporation results in 4% shrinkage during the trip back over the hills.
Annual precipitation amounts to 65.4 inches annually (sidereal), however the pan evaporation rate averages 5.881 mm a day (assume a discount of 25% to account for ‘pan’ effects). King Arthur, Guinevere, and the residents of Northumberland are alloted an imperial gallon and a half of water out of the moat for general hygiene purposes. The castle inhabitants include the King, Guinevere and a score and a half of hand maidens, stable hands, and other miscellaneous servants. However, the generous King insists each of the inhabitants take 15 days of vacation every ten sidereal years and leave the castle to spend time at the all-inclusive Berwick-upon-Tweed resort on North Sea. The King and Guinevere spend three weeks each solar year at the castle.
The day Merlin begins his quest to fill the moat is his 28th birthday and the moat contains 412 barrels of water from hydrotest residual and precipitation. How old will Merlin be when he finally fills King Arthur’s moat?
For my answers to the units on the conversion factors above and Merlin's age at the end of his quest - click here.