11.1.4 Fluid Sample

A total of three fluid samples exist in the worked example:

1. Sample is acquired, found to be invalid and destroyed.
2. Sample is acquired and retained, and used for hydrocarbon analysis.
3. Sample is sub-sampled from Sample 2, with a water sample being removed and used for water analysis.

Important information about the sample concerns its provenance: where it came from in the reservoir, and which operation created it. This aspect is shown in Figure 11.1.4-1 .

Figure 11.1.4-1 Fluid sample showing references to its provenance.

Note that the fluid sample container for a fluid sample is not a 1:1 correspondence because the sample may be moved between containers during its lifetime. The original fluid sample container is recorded with the fluid sample acquisition job. Any subsequent changes are recorded in the fluid sample chain of custody event element. Two such are recorded for Sample 2:

1. Custody transfer to a new custodian (a PVT Lab), also recording the current fluid sample container.
2. Sub-sample of dead fluid taken. This is into a new container and creates a new fluid sample. This event is shown in detail in Figure 11.1.4-2 .

Figure 11.1.4-2 Fluid sample chain of custody event— showing a sub-sample of aqueous phase being taken.

Note that while not shown in the example, an important feature of the model is the ability to combine samples into a new sample, for example recombining separator oil and gas phase samples.