Applications In Heavy Oil Recovery Research Articles

Application of a novel amphiphilic polymer for enhanced offshore heavy oil recovery: Mechanistic study and core displacement test

A molecular modified polyacrylamide with Gemini surfactant monomers, named as HA1, was evaluated in this paper as an alternative to enhance the offshore heavy oil recovery. The physical properties of HA1 solution including apparent viscosity, rheological properties, static adsorption, interfacial activities (IFT, interfacial visco-elasticity and contact angle), emulsification ability, as well as oil recovery capacity were comprehensively investigated. Our results indicate that due to the hydrophobic and Gemini surfactant monomers on the acrylamide backbone, this novel amphiphilic polymer possesses more advanced functions than conventional polymers. HA1 demonstrates pronounced aqueous-phase viscosifying ability by forming 3D network in solution when the concentration is above CAC. In addition, the IFT, interfacial visco-elasticity and contact angle response illustrate that HA1 interacts strongly with the oil-phase which gives rise to its significant interfacial activity. Thereby, HA1 is able to reduce the heavy oil viscosity by emulsifying oil into water phase even at relatively low water content (20%) and also avoids dehydration difficulty by reducing the oil-brine interfacial rigidity. Furthermore, the asphaltene morphology change due to HA1 observed by SEM and AFM proves that HA1 can disperse the asphaltene aggregates in the crude oil, leading to a direct reduction of the heavy oil viscosity. At last, the coreflooding in an artificially synthesized triple-layered porous media shows that HA1 gives rise to an additional oil recovery of 27.04%, at the optimum concentration of 1600 ppm, by improving sweep efficiency, microscopic efficiency and dispersion of the asphaltene aggregates. Therefore, the potential of HA1 to enhance heavy oil recovery is comparable to traditional multi-component polymer-surfactant flooding. Since HA1 is single-component, it can also mitigate incompatibility issues like chromatography separation and surfactant-polymer interactions. Overall, this new self-assembly system shows potential for applications in heavy oil recovery.

Enhancement of Heavy Oil Recovery with High CO2 Injection Rates in Silica Nanochannel

Abstract CO2 injection enhanced oil recovery has become one of the most important approaches to develop heavy oil from reservoirs. However, the microscopic displacement behavior of heavy oil in the nanochannel is still not fully understood. In this paper, we use CO2 as the displacing agent to investigate the displacement of heavy oil molecules confined between the hydroxylated silica nanochannel by nonequilibrium molecular dynamics simulations. We find that for heavy oil molecules, it requires more much higher displacing speed to fully dissipate the residual oil which is found related to the decreased CO2 adsorption on the silica nanochannel. A faster CO2 gas injection rate will lower the CO2 adsorption inside the nanochannel, and more CO2 will participate in the displacement of the heavy oil. The results from this work will enhance our understanding of the CO2 gas displacing heavy oil recovery and design guidelines for heavy oil recovery applications.

Novel self‐assembling polymeric system based on a hydrophobic modified copolymer: formulation, rheological characterization, and performance in enhanced heavy oil recovery

This work presents the chemical formulation and rheological properties of a novel self‐assembling polymer (SAP) system derived from a hydrophobically modified sulfonated polyacrylamide (HMSPAM). This polymeric association was established through complexation between the pendant hydrophobic groups contained in HMSPAM and β‐cyclodextrin molecules. The new SAP system offers improved viscoelastic properties because of the “interlocking effect” of the hydrophobic groups into β‐cyclodextrin cavities. It also provides suitable reformability upon mechanical shear when compared to the base HMSPAM. Furthermore, SAP exhibits superior tolerance to elevate brine salinity and hardness, as well as high reservoir temperature. Sandpack flooding tests conducted at simulated reservoir conditions (Pelican Lake reservoir, Alberta, Canada) indicate that this system shows superior mobility control (resistance factor) compared to HMSPAM. It also shows potential as in situ permeability modifier, which makes this polymeric system particularly suitable for heavy oil recovery applications. For instance, the newly developed SAP produced 20% more incremental heavy oil recovery if compared to the performance of the commonly used partially hydrolyzed polyacrylamide and 7% more incremental oil recovery than the baseline HMSPAM at the same experimental conditions. Overall, this new self‐assembly system shows potential for applications in heavy oil recovery. Copyright © 2014 John Wiley & Sons, Ltd.