Separation
Foaming
When produced and transported from the reservoir to processing facilities, fluids experience a drop in pressure. This will release dissolved gases that can cause the fluids to foam. Evolved gas is removed in a separator, but foaming can lead to liquid carry-over into the gas stream, disrupting gas processing. Stable foams may also upset separator level control.
How it works
Using gas-sparging rigs developed at KAT, foaming tendency is measured in terms of volume or height of the foam column and foam stability in terms of its collapse time.
Temperature and gas flow may be altered to suit field conditions. The rate of gas release can also be measured by monitoring the change of density with time. The performance of ‘antifoam’ chemicals can easily be examined by dosing the crude sample under test.
Emulsions
Crude oil is frequently produced with water that must be separated and removed to meet export specifications. The behaviour of emulsions, including stability and viscosity, are not only dependent on temperature, water-cut and composition but are also highly dependent on the severity and duration of mixing
How it works
At KAT, emulsions are prepared under prescribed mixing regimes, with either a laboratory blender or homogeniser, to simulate anticipated production conditions [i.e., representative of low turbulent flow to high shear ESP pumps]. Measurement of percentage water drop-out over time along with visual inspection of the separated water quality, emulsion pad, and droplet size and distribution by microscopy are used to assess subsequent water separation.
The apparent viscosity of a stable emulsion formed from a waxy oil can be several orders of magnitude higher than the dry oil at water cuts approaching the inversion point. Depending on the stability of the emulsions, Viscosity vs. Temperature profiles at several shear rates [ranging from 1 to 200s-1] or controlled-shear flow curves [up to a maximum 1000s-1] at a range of discrete temperatures can be performed at KAT to characterise the potential impact on the flow performance of a system.
Fluid Analysis
KAT offers a suite of analyses to characterise crude oil and gas condensate samples and help assess the potential impact on production operations.SARA [latroscan]Separates the test fluid into four solubility classes: Saturate (Paraffin), Aromatic, Resin, and Asphaltenes using the Iatroscan…
Asphaltenes
Asphaltenes are a natural constituent of many crude oils and may be precipitated in production systems when the crude’s natural solvency for them is reduced. Several factors including, pressure, temperature, and composition can change the stability of these high molecular…
Separation
Foaming When produced and transported from the reservoir to processing facilities, fluids experience a drop in pressure. This will release dissolved gases that can cause the fluids to foam. Evolved gas is removed in a separator, but foaming can lead…
Gas Hydrates
Gas hydrates are crystalline solids with cage-like structures [clathrates] in which a hydrocarbon molecule is enclosed in a lattice of water molecules. Although they have the appearance of ice or snow, gas hydrates crucially form at pressures and temperatures above…
Oilfield Scale
Oilfield scale is the term used to describe deposits of insoluble inorganic minerals such as calcium carbonate, barium sulphate, and metal sulphides. In general, scale deposits occur when waters with different ion contents are mixed although pressure and pH can…
Rheology
Dynamic Viscosity Dynamic Viscosity vs. Temperature curves for assessing the flow behaviour of a waxy [Non-Newtonian] fluid are produced at a range of shear rates corresponding to typical production flowrates during normal steady-state pipeline flowing conditions. As such, each curve…
Wax Appearance
Waxes are generally defined as paraffinic material with carbon numbers greater than nC17. Waxes are present in oil as a distribution of molecular weights and thus exhibit a range of solubilities, precipitating over a range of conditions. Precipitation is temperature…
Wax Deposition
The build-up of solid waxy layers onto cooled surfaces such as pipe walls is generally considered to be a temperature-dominated phenomenon. Several theories have been proposed to describe the effect and several commercial semi-empirical models have been developed to predict…
Arn Acids
Napthenate Solids Naphthenate solids are naturally occurring oilfield fluid scales formed from reactions between a specific group of high molecular weight cyclic naphthenic ARN acids, also known as Tetra Protic Acids or Tetra-Acids, with dissolved divalent cations [such as Ca,…
T-SEP®
Compared to the relatively high concentrations of nC10 – 20 in crude oils and gas condensates [analysed as unadulterated “Whole” sample] the concentrations of >nC30 can be relatively low and either close to or below the limit of detection /…