Page 27 - Geochemistry of Oil Field Waters

16 SAMPLING SUBSURFACE OILFIELD WATERS

it may be feasible to collect the sample from a nonheated separator or
heater; samples are not to be taken of water that has been heated or treated
with any chemicals. Glass sample bottles (about 100 ml usually is sufficient)
should be used, and the sample should overflow the bottle. The bottle
should be closed with a cap equipped with a plastic insert, and the top
should be sealed with wax to minimize exchange reactions with air.

Sample containers

Various factors influence the type of sample container that is selected.
Containers that are used include polyethylene, other plastics, hard rubber,
metal cans, and borosilicate glass. Glass will absorb various ions such as iron
and manganese, and may contribute boron or silica to the aqueous sample.
Plastic and hard rubber containers are not suitable if the sample is to be
analyzed to determine its organic content. A metal container is used by some
laboratories if the sample is to be analyzed for dissolved hydrocarbons such
as benzene.

TABLE 2.111
Description needed for each petroleum-associated water sample
__ --
Sample number Field
Farm or lease Well No. in the
of Section Township Range __
County State - Operator __
Operator’s address (main office) - -___
Sample obtained by -_____ Date ~
Address ~ Representing ~
Sample obtained from (lead line, separatory flow tank, etc.)
Completion date of well Elevation of well ___
Name of productive zone from which sample is produced -
Sand - Shale Lime ~ Other
Name of productive Names of formations
formation well passes through
Depths: Top of formation Bottom of formation
Top of producing zone Bottom of producing zone
Total depth drilled Present depth
Bottom hole pressure and date of pressure
Bottom hole temperature
Date of last workover be any chemicals If yes,
added to treat well? -what?
Well production Initial Present Casing service record:
Oil, barrelslday -
Water, barrels/day
Gas, cubic feetlday _______
Method of production (primary or secondary)
Remarks: (such as casing leaks, communication, or other pays in same well, lease, or field)