Volumetric behaviour of (carbon dioxide + hydrocarbon) mixtures at high pressures

TL;DR

This study measures the densities of CO₂ + hydrocarbon mixtures at high pressures and temperatures to aid in enhanced oil recovery process design, using an advanced densimeter and a new injection system.

Contribution

It introduces a new high-pressure measurement setup and provides detailed density data for CO₂ + hydrocarbon mixtures relevant to oil recovery.

Findings

Densities of CO₂ + hydrocarbons were measured at various temperatures and pressures.

The developed system achieves an uncertainty of ±0.9 kg·m⁻³ in density measurements.

Data supports improved modeling of CO₂ injection processes in heavy oil recovery.

Abstract

The interest of oil industry in increasing heavy oil production has promoted the use of enhanced oil recovery techniques such as $CO_{2}$ injection, which produce a decrease of oil viscosity and displacement of heavy oil from reservoir to surface. The design of these processes requires accurate data of densities, viscosities or surface tensions of ($CO_{2}$ + hydrocarbon) mixtures in order to simulate the behaviour of these mixtures in the reservoir. An automated Anton Paar DMA HPM vibrating-tube densimeter was used to measure densities of this kind of mixtures, and a new mixture injection system, by means of two syringe pumps, was developed for the densimeter. The equipment operates at high pressure, which is controlled through a back pressure valve and a variable volume cylinder with a stepper motor. The estimated standard uncertainty of the density is $\mathrm{\pm0.9 \ kg \cdot m^{-3}}$ at temperatures below 373.15 K and pressure range (0.1-140) MPa.In this paper, the densities of the mixtures ($CO_{2}$ + $n$-decane), ($CO_{2}$ + $n$-dodecane) and ($CO_{2}$ + squalane) are reported at $T$ = (283.15-393.15) K and $p$ = (10-100) MPa.