Coupling Microfluidics Data with Core Flooding Experiments to Understand Sulfonated/Polymer Water Injection

Abstract

The injection of sulfonated-modified water could be an attractive application as it results in the formation of a mechanically rigid oil-water interface, and hence, possible higher oil recovery in combination with polymer. Therefore, detailed experimental investigation and fluid-flow analysis into porous media are required to understand the possible recovery mechanisms taking place. This paper evaluates the potential influence of low-salt/sulfate-modified water injection in oil recovery using a cross-analyzed approach of coupled microfluidics data and core flooding experiments. Fluid characterization was achieved by detailed rheological characterization focusing on steady shear and in-situ viscosity. Moreover, single and two-phase micromodels and core floods experiments helped to define the behavior of different fluids. Overall, coupling microfluidics, with core flooding experiments, confirmed that fluid-fluid interfacial interaction and wettability alteration are both the key recovery mechanisms for modified-water/low-salt. Finally, a combination of sulfate-modified/low-salinity water, with polymer flood can lead to ~6% extra oil, compared to the combination of polymer flood with synthetic seawater (SSW). The results present an excellent way to make use of micromodels and core experiments as a supporting tool for EOR processes evaluations, assessing fluid-fluid and rock-fluid interactions.

Variations in Wettability and Interfacial Tension during Alkali–Polymer Application for High and Low TAN Oils

“…However, the aging process altered the rock surface, which became hydrophobic, resulting in oil polar compounds attaching to the rock surface. The wettability alteration to oil-wet (shown in Figure 13 ), based on our previous work [ 35 , 42 ], confirmed the change in contact angle to 41. The wettability alteration of the Berea and Bentheimer sandstone core plugs through a two- or three-week aging process has also been established by many researchers [ 43 , 44 , 45 , 46 , 47 ].…”

“… Two groups of cores were considered during the process, aged and non-aged, to assess any wettability shift at reservoir temperature. Core aging at reservoir temperature for around 800 h was reported to lead to a wettability shift from a purely water-wet state of the cleaned core samples to a neutral or oil wet state [ 3 , 34 , 35 ]. Amott spontaneous imbibition experiments were performed for different defined cases considering the influence of TAN, core plug aging, brine composition, and clay rock content.…”

On the Role of Polymer Viscoelasticity in Enhanced Oil Recovery: Extensive Laboratory Data and Review

“…Generally, an increase of the polymer concentration results in an increase of viscoelasticity as well as of viscosity. This behavior is proved by a broad range of literature such as the advanced experimental works of Howe et al [ 25 ], Clarke et al [ 55 ], Hincapie [ 8 ], Rock et al [ 30 ], Heemskerk [ 114 ], Tahir et al [ 84 ] and Seright et al [ 115 ].…”

“…Therefore, it is necessary to measure the rheological properties of the viscoelastic polymer solutions within porous media. Moreover, a combination of both rheometer data and data obtained from flooding experiments within porous media (e.g., sand pack, core plugs and micromodels) allows the correction of the shear rate [ 60 , 63 , 66 , 72 , 84 ]. This is necessary because shear rates are only calculated in flooding experiments and, hence, have a certain degree of inaccuracy.…”

Recovery Observations from Alkali, Nanoparticles and Polymer Flooding as Combined Processes

“…Enhanced oil recovery (EOR) methods promote fluid–fluid (F–F) and rock–fluid (R–F) interactions due to the injection of external agents not initially present in the reservoir [ 1 , 2 ]. Fluid–fluid interactions define static as well as dynamic interfacial properties at the oil–brine–system interface, considering the possible chemical interactions taking place [ 3 , 4 , 5 , 6 , 7 , 8 ]. Moreover, rock–fluid interactions could result not only in wettability alterations [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], but also in fine migration, often leading to permeability changes [ 15 , 16 ], and other possible mechanisms related to the transport in porous media.…”