Laboratory investigation of Surfactant and Polymer formulation design for Heavy Oil recovery in sand stone reservoirs

Laboratory investigation of Surfactant and Polymer formulation design for Heavy Oil recovery in sand stone reservoirs

Chemical flooding is classed as an important technique of Enhanced Oil Recovery (EOR) which has been applied throughout the globe since the 1980s. The outcomes of such flooding have mainly been effective in both onshore and offshore locations with the latter being more challenging due to factors such as weather; challenges associated with logistics of chemicals and high salinity content in sea waters. Nonetheless, there has been significant incremental oil recovered in offshore location especially during the last couple of decades (Manrique 2007). The contributing factors behind the success rate of such flooding are mainly due to the combination of chemicals used. The surfactant and polymer used in chemical flooding would help in producing more oil which was previously out of reach through various mechanisms such as the lowering of Interfacial Tension (IFT) between the phases in the reservoir as well as improving the sweep efficiency. 

Vast amount of research has been done on chemical flooding, however, the effect of various combinations of chemicals used in Alkaline, Surfactant, Polymer (ASP) flooding on the mechanism behind changes in the capillary pressures have not been fully clarified (Shen, 2007).

Research carried out by Zhang et al. (2012) indicated that it was possible was to develop an ASP flood which could recover incremental oil at low surfactant concentrations. They performed a series of phase behavior tests, interfacial tension (IFT) measurements and core flood test in order to develop a solution for oil that had an API gravity of 15 and viscosity of 2,000 cp. The result indicated an incremental recovery of 6 % in comparison with previous water flooding (Zhang, 2012).

Furthermore, in recent research by Sheng, 2013, the need for development of ASP formulation with high temperature and high salinity limit has been highlighted. The advantage of ASP formulation over its individual process is the synergy between the polymer, surfactant and alkaline used. To have this synergy, the components of alkaline, surfactant and polymer must be in the same slug (Sheng, 2013). For example, in alkaline-polymer flooding, alkaline reaction with crude oil results in soap generation, wettability alteration, and emulsification; and polymer provides the required mobility control. Alkaline-polymer flooding can displace more residual oil than individual alkaline flooding or polymer flooding (Sheng, 2013).

Moreover, it was reported by Sheng, 2013 that when surfactant and polymer were injected in the same slug (SP flooding), their compatibility was an issue. In some cases, polymer was injected before surfactant as a sacrificial agent for adsorption or for conformance improvement. Sometimes polymer was injected behind surfactant to avoid chase water fingering in the surfactant slug. Even though polymer was not injected with surfactant in the same slug, they mixed at their interface because of dispersion and diffusion. Polymer may also mix with surfactant owing to the inaccessible pore volume phenomenon when it is injected behind surfactant. Sheng referred to these phenomena as surfactant-polymer interaction or incompatibility. Cases such as this are examples of the possible interaction that polymer and surfactant can have once injected into the reservoir. These interaction sometimes have negative or positive effect of the performance of the chemicals.

In other researches, the effectiveness of associative polymers in displacing of oil has been reported (Wever, 2011). The main attraction of associative polymers for EOR is their significant viscosity enhancement ability compared with conventional polymers and their potential salinity resistance in real oil field applications (Wever, 2011).

An example of an associative polymer is Phenyl-polyacrylamide (PPAM) which is a hydrophobic synthesized Polyacrylamide (PAM). Such synthesized polymers can be used as a more effective mobility control agent in future research. It is worth mentioning that PPAM is a non-commercial type of polymer which has been developed in laboratory at London South Bank University. The results of recent tests carried out at LSBU showed that PPAM had higher resistance to salinity conditions and also higher viscosity at the same concentration compared to PAM. 

Research Aims

The aim of this research is to study the synergy between the use of hydrophobic modified acrylamide and series of surfactants. This would be achieved through understanding the synergy between the candidate surfactants and polymers such as PPAM used in the core flooding. The subsequent findings around the synergetic effects will be used to design an effective chemical flooding more resistant to salinity and thermal conditions with the view of achieving higher efficiency in fluid displacement.

Research Objectives

·         Study in detail the chemical composition and structure of candidate polymer, surfactant and alkaline
·         Understand in details the synergy between the candidate polymer, surfactant and alkaline.
·         Develop an ASP formulation, with tolerance to high salinity and high temperature conditions, based on the understanding around the synergy of candidate polymer, surfactant and alkaline.

Research Methodology

Experimental work

It is of importance to embrace the candidate reservoir characteristics in order to design EOR fluid. One way of accomplishing this is through laboratory analysis where fluid-fluid and rock-fluid interactions are evaluated. Doing so, it is possible to introduce solutions tailored to each candidate reservoir.

Series of laboratory experiments are listed below:

·           Injectivity and sweep efficiency (core flooding)
·           Filterability test: To evaluate the presence of undissolved solids in the SP solution and to identify a possible plugging behaviour.
·           Viscosimtry test: Provides the viscosifying power of the polymer solution, allowing the calculation of polymer consumption (rheometer)
·           Adsorption: Evaluates the adsorption levels in core sample (UV-spectrophotometric.)
·           Resistance factor: Evaluates the possibility of reduction in permeability due to polymer injection, if any.
·           IFT measurement: Determine the optimum concentration of the SP solution (tensiometer).
·           Thermal Stability test: evaluate the performance of SP solution at various temperatures
Chemicals under evaluation

·         Primarily, the already available chemicals such as Phenyl-polyacrylamide (PPAM), Hydrolyzed Polyacrylamide (HPAM) and KYPAM will be used in experiments.
·         Surfactants such as Linear alcohol ethoxylates, Nonylphenol ethoxylates, petroleum sulfonates and synthetic alkyl sulfonates, Alkyl Ether Carboxylates

Simulation modelling

A probabilistic approach will be taken toward the findings of this project by means of embracing the uncertainties associated with subsurface and surface elements. Through Risk and uncertainty analysis it would be possible to reduce the error margins. This can be achieved by means of Experimental Design in order to take into consideration all possible development scenarios of a project.


§  Sheng. J, 2013. A Comprehensive Review of Alkaline-Surfactant-Polymer (ASP) Flooding. Paper SPE 165358, presented at the 2013 SPE Western Regional &AAPG Pacific Section Meeting, California, USA, 19-25 April 2013.
§  Manrique, E; Muci.V.E; Gurfinkel, M. “EOR Field Experiences in Carbonate Reservoirs in the United States”. SPE 1000063, paper presented at the 2006 SPE/DOE Symposium on Improved Oil Recovery held in Tulsa, Oklahoma,  22-26 April, 2006.
§  Shen, P., Wang, J., Yuan, S., Zhon, T., Jla, X., “Study of Enhanced-Oil-Recovery Mechanism of Alkali/Surfactant/Polymer Flooding in Porous Media from Experiments “.  SPE 126126 presented at the International Petroleum Technology Conference held in Dubai, 4-6 December 2007.
§  Wever, D., Broekhuis, F., Polymers for enhanced oil recovery: A paradigm for structure-property releationship in aqueous. Pogress in Polymer Science. 36,11,p.1588-1628, November 2011.
§  Zhang, J., Ravikiran, R., Freiberg, D., Thomas, C., 2012. ASP Formulation Design for Heavy Oil. Paper SPE 153570, presented at the Eighteenth SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, 14-18 April 2012.


Arash Farhadi.