Page 65 - Handbook Of Multiphase Flow Assurance

60 3. PVT and rheology investigation

Asphaltene deposition study in a pressure cell
Asphaltene deposition study in a mini-loop or a filter-plug apparatus

Corrosion rate metal loss study with a static cell
Corrosion rate study with a rotating linear polarization electrode at atmospheric pressure
to measure the effect of shear on chemical performance
Corrosion rate with a rotating electrode under high temperature and high pressure
Corrosion rate from analog field metal coupon weight loss

Scale precipitation study in a static cell
Scale deposition in a mini-loop at high temperature to mimic reservoir condition
Scale deposition in a mini-loop at low temperature to mimic wellhead & flowline condition

Hydrate stability study with reservoir fluid and formation water
Hydrate stability study with reservoir fluid and wellwork fluid
Hydrate deposition study in a pressure autoclave, a rocking cell, a flow wheel or a flow
loop, with or without chemical thermodynamic or kinetic inhibitors
Hydrate dispersion study in a rocking cell with antiagglomerant chemicals
Among the above tests, there are some indirect correlations:

Hydrate nonplugging oil tendency may be related to TAN acids content and surfactants
content as investigated by J. Sjoblom, where surfactants content may be analyzed based
on emulsion stability study
Naphthenate tendency may be related to TAN acids content
Asphaltene tendency may be determined from SARA analysis

Production chemicals viscosity as function of pressure and temperature
Production chemicals vapor pressure analysis

There are numerous alternatives available to measure wax appearance and wax disappear-
ance temperatures, which should be used depending on fluid type (e.g. regular or biodegraded):
- CPM—visual detection of microscopic crystals assisted by polarized visual or IR light
- DSC—exothermic detection of solids, applicable to regular or biodegraded oils
- Viscometer or rheometer—detect a change in slope of Ln(viscosity) vs temperature
- Cold finger—visual detection of solids
- Cold filter plug—pressure differential detection of solids
- Cloud point—visual detection of crystals by eye—less accurate but field-usable
- Ultrasound change in wave frequency with temperature—applicable to live oil (Jiang
et al., 2014)
- Light scattering—applicable to wax appearance and wax disappearance

Compressibility.
PVT tuning

Binary interaction parameters k ij serve as the tuning factors for the equations of state when
properties of multicomponent mixtures are calculated. These BIPs are regressed for multiple