Modeling of asphaltene and water associations in petroleum reservoir fluids using cubic‐plus‐association EOS

Abstract

Asphaltene is a group of complex compounds commonly present in petroleum reservoir fluids. It is conceivable that asphaltenes strongly interact with water through hydrogen bonding, affecting phase behavior of water/oil mixtures with/ without forming an asphaltene-rich phase. In this research, the cubic-plus-association equation of state (CPA EOS) is applied to multiphase behavior resulting from self-and cross-associations of asphaltenes and water in petroleum fluids. This article also presents a new correlation for binary interaction parameters for water with n-alkanes for the CPA EOS by using three-phase data for water/n-alkane binaries. A method is proposed to characterize mixtures of asphaltene-containing oil with water using the CPA EOS. Results show that the CPA EOS can represent multiphase behavior for water/oil mixtures with up to four equilibrium phases: asphaltene-rich, solvent-rich, aqueous, and vapor phases. Case studies include bitumen/water mixtures, involving asphaltene-water emulsion, water solution in bitumen, and their continuous transition with varying temperature.The experimental data were taken from Skripka. 44 The BIP for the CPA is 0.2410 with Eq. 16, and 0.0095 with Eq. 17. The BIP for the PR EOS is 0.5529. n b refers to the number of water molecules bound to one asphaltene molecule.

Modeling of Gas Migration in Large Elevation Difference Oil Transmission Pipelines during the Commissioning Process

“…The pipe is firstly filled with atmospheric air before the water enters into the pipe. When the water flows over the high point of the pipe, some air accumulates at the high point of the pipe, and the water flows by itself to the low point of the pipe in the form of a dissatisfied flow [33]. At this time, the flow of water can be regarded as the flow of an open channel.…”

Vapor–Liquid–Liquid Equilibrium Modeling of Water/Bitumen/Solvent (C1, C2, C3, and n-C4) Mixtures Using a Cubic-Plus-Association Equation of State

“…This result shows that selecting the BIP as an adjusting parameter in tuning the CPA EoS is a promising approach. In addition, if one splits bitumen into asphaltene- and maltene-rich components, selecting the water–maltene BIP as one of the adjusting parameters enables the CPA EoS to precisely determine phase boundaries . Moreover, Zhang et al predicted different physical properties of the propane/pentane/bitumen system using the CPA EoS and used the BIP between the solvent and asphaltene as one of their adjusting parameters.…”