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, Mg and Fe] that come from the associated produced water in some oilfields. These hard solids can restrict production and in extreme cases render control systems inoperable and shutdown production.
Sodium Carboxylate Soaps
Sodium Carboxylate soaps are formed from shorter chain, carboxylic ARN acids, also known as Fatty acids. The soaps are responsible for stabilising emulsions which in turn can adversely impact oil dehydration, fluid desalting, produced water treatment and disposal, oil storage and export.
ARN Acid Analyses
In collaboration with the University of Plymouth, C80-82:0-8 tetra protic acids present in a test fluid or solid sample can be extracted by sequential ion exchange solid phase extraction, as described by Sutton and Rowland [2014; Energy and Fuels, 28, 5657-5669 (DOI: 10.1021/ef5012337)], and semi-quantified using liquid chromatography coupled with heated electrospray ionisation/high resolution accurate mass spectrometry [LC/HESI/HRAM-MS].
The KAT / University of Plymouth partnership can also provide the distribution of the nC8-20 carboxylic acids [identified as their methyl esterified derivatives by HTGC].
Precipitation Bottle Tests
If ARN acids present an issue with respect to solids deposition or emulsion stability, then precipitation bottle tests can be performed to assess water and oil interface layers for evidence of carboxylate soap formation or naphthenate precipitation. Similarly, the bottle tests can be used to screen potential chemical management solutions.
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 /…