Page 460 - Handbook Of Multiphase Flow Assurance

460 14. Case studies/reference material

Gas phase envelopes
300

METHANE
250 LEAN GAS
RICH GAS
RETROGRADE
200
Pressure (atm) 150 C

100
C

50 C
C

0
–200 –150 –100 –50 0 50 100 150 200 250 300
Temperature (°C)
FIG. 14.1 Comparison of phase envelopes for methane, lean gas, rich gas, and retrograde fluid.

The difference of retrograde fluid may be seen in the location of its critical point, where
liquid and vapor densities are the same, on the P-T graph, being on the low temperature side
of the phase envelope as shown in Fig. 14.1.

Abbreviations and definitions

Commonly used abbreviations, acronyms, and definitions as as well as some of the indus-
try standards applicable to flow assurance are are shown in Tables 14.5 and 14.6.

Regulatory requirements and environmental law which may affect flow
assurance

Regional regulatory requirements have to be identified at the project consideration stage
because of their high impact on the project. A list of applicable regulatory requirements have
to be included as a list in the basis of design document. Examples of requirements that may
affect flow assurance include:

• Guidelines or restrictions on production and chemical use methods
• Guidelines on use of gas gradient for shut-in tubing pressure calculation
• Imposed chemical restrictions or toxicity limits
• Waste management/handling regulations