Correlations between Crude Oil Composition and Produced Water Quality: A Multivariate Analysis Approach

Abstract

A matrix of 18 synthetic produced water samples was analyzed by partial least-squares (PLS) regression modeling. This has been done to investigate the correlation between crude oil properties and water solubility and affinity of the dissolved hydrocarbons for air/water interface which is referred to as produced water quality. The synthetic produced water samples were prepared with nine crude oils and two aqueous phases in the presence and absence of divalent cations (Ca2+, Mg2+). The total organic carbon content and dynamic surface tension was determined for the samples. The findings of the PLS modeling are summarized as follows: produced water quality was not correlated to the amount (wt %) of aromatics, resins, and asphaltenes in the crude oils but with the amount (wt %) of heteroatoms present in the different fractions. The water solubility and affinity for air/water interfaces of the crude oil hydrocarbons was promoted by oxygen-containing compounds and reduced by nitrogen- and sulfur-containing compounds. Heteroatom-containing molecules of similar class originating from aromatic, resin, and asphaltene fractions of crude oils contributed to different degrees of water solubility and affinity for adsorption at air–water interfaces. This can be related to the differences in the molecular structures of the compounds. Furthermore, the presence of divalent cations showed more influence on the quality of produced water samples of crude oils with high total acid number and nitrogen content.

Novel Bionanocompounds: Outer Membrane Protein A and Laccase Co-Immobilized on Magnetite Nanoparticles for Produced Water Treatment

“…Nonylphenol ethoxylate at 10 mol (NPE10) with HLB 13.2 was used as a surfactant to achieve a stable direct emulsion, as described by Loh et al [ 62 ]. For stabilization, the continuous phase was prepared as a brine solution following the procedure described in Øye et al [ 63 , 64 ]. The composition of the prepared brine is shown in Table 1 .…”

Microfluidic Investigation of Crude Oil Droplet Coalescence: Effect of Oil/Water Composition and Droplet Aging

“…conducted bench and technical scale experiments with a large matrix of oils to map the relation between the crude oil properties and the separation performance 28 . Eftekhardadkhah and Øye investigated the effect of the crude oil and water composition on the concentration and interfacial activity of the dissolved components in produced water 29 . Their study showed good correlation between the water quality and the presence of certain heteroatom-containing groups in crude oils.…”

Effects of Divalent Salts on the Interfacial Activity of the Mixed Surfactants at the Water/Model Oil Interface

“…NaCl may compact the surfactant layers by neutralizing the charges of their head groups, decreasing the IFT value. The high NaCl concentration causes the salting‐out effect, resulting in the IFT increase (Eftekhardadkhah and Øye, ). Once MgCl 2 was added to the system, the surfactant layers are intensive enough to weaken the effects of NaCl.…”

“…Many reports focused on the effects of salts on the interfacial activity of surfactants (Anachkov et al, 2015;Cao et al, 2012;Gandomkar and Rahimpour, 2017;Johnson et al, 2017;Lashkarbolooki et al, 2016;Lashkarbolooki and Ayatollahi, 2018;Liu et al, 2013Liu et al, , 2014Robertson et al, 2013;Sharma and Sangwai, 2015;Tichelkamp et al, 2014Tichelkamp et al, , 2015Tummons et al, 2017). The addition of salts can affect surfactants in the following ways (Cayias et al, 1976;Eftekhardadkhah and ye, 2013): First, the electrostatic attraction between the counterions and the charged heads of ionic surfactants compresses the occupied area of surfactant head groups at the interface and increases their effective concentrations. Second, the counterions, especially at a high concentration, may greatly enhance the hydrophobicity of the surfactants via electrostatic neutralization.…”