Application of Organic Alkali for Heavy-Oil Enhanced Oil Recovery (EOR), in Comparison with Inorganic Alkali

Abstract

Alkali is an important component for alkali/surfactant/polymer technology for enhanced oil recovery (EOR). The mechanism and advantages of traditional inorganic alkali for EOR was reviewed in this paper. The rheological and dynamic properties of the combination of alkali and polymer were analyzed. The results show that the polymer solution with ethanolamine has better shear viscosity and elastic properties at room temperature. Surfactant (Alfaterra 123-8S-90) with concentration of 0.15 wt % was added into each alkali−polymer (AP) solution. No significant change was observed in rheological properties of AP solutions with and without surfactant. Emulsification tests show that ethanolamine has better performance with oil. Injectivity tests were also conducted. The results indicated that the residual resistance factor (RRF) for an ethanolamine− polymer solution is always higher at each flow rate tested, in comparison to a NaOH-based AP solution, which is beneficial for oil recovery. The interfacial tension (IFT) tests results indicated that ethanolamine has better synergy with the surfactant. Polymer adsorption using both static and dynamic measurements was conducted. Polymer solution in an ethanolamine system has lower adsorption for both measurements. The pressure comparison during core flooding experiments shows that it has higher injection pressure in ethanolamine conditions, which result in good sweep efficiency. The ethanolamine−polymer flooding showed a significant increase in oil recovery (15.33%) over NaOH−polymer flooding. After the addition of surfactant, the total recovery improves by 14.8% for ethanolamine−polymer−surfactant flooding over its inorganic counterpart. The better performance indicates that ethanolamine can become a potential alkali and can replace NaOH for EOR.

Interfacial Properties, Wettability Alteration and Emulsification Properties of an Organic Alkali–Surface Active Ionic Liquid System: Implications for Enhanced Oil Recovery

“…Despite the promising nature of various chemical floodings and their hybrid techniques, the chemicals deployed have associated limitations that inhibit their worldwide application [ 9 ]. The inorganic alkalis conventionally deployed, like NaOH and Na 2 CO 3 , cause severe scaling problems, which impair reservoir permeability and lead to loss of production capacity [ 10 , 11 , 12 , 13 ]. Conventional surfactants have serious environmental concerns due to their low biodegradability and biocompatibility.…”

The seepage flow characteristics of hydrophobically associated polymers with different aggregation behaviours in porous media

“…(2) The research adopts displacement experimental process equipment as described in figure 4. The concrete steps are as follows [35][36][37]: (i) The sand pack was vacuumed and saturated with the synthetic brine. Porosity was calculated based on the weight difference before and after the sand pack was saturated with brine.…”

Insights into Enhanced Oil Recovery by Polymer-Viscosity Reducing Surfactant Combination Flooding in Conventional Heavy Oil Reservoir

“…However, the alkali in the ASP flooding system can cause some problems, which can restrict the application of ASP flooding. The alkali can react with rock mineral to cause severe scaling problems and promote the formation of water-in-oil (W/O) emulsion in the produced liquids that is too stable to be broken [31][32][33][34][35][36][37][38][39][40][41][42][43][44]. In addition, the high consumption of alkali for the heavy oil with low acid number, which will lead to saltsensitive effect and reduce the viscosity.…”