Tertiary-Recovery Improvement of Steam Injection Using Chemical Additives: Pore-Scale Understanding of Challenges and Solutions Through Visual Experiments

Tertiary Recovery Improvement of Steam Injection Using Chemical Additives: Pore Scale Understanding of Challenges and Solutions Through Visual Experiments

10.2118/200841-ms ◽

2021 ◽

Author(s):

Randy Agra Pratama ◽

Tayfun Babadagli

Keyword(s):

Porous Media ◽

Phase Change ◽

Oil Recovery ◽

Heavy Oil ◽

Phase Distribution ◽

Steam Injection ◽

Hot Water ◽

Heavy Oil Recovery ◽

Residual Oil ◽

Tertiary Recovery

Abstract Our previous research, honoring interfacial properties, revealed that the wettability state is predominantly caused by phase change—transforming liquid phase to steam phase—with the potential to affect the recovery performance of heavy-oil. Mainly, the system was able to maintain its water-wetness in the liquid (hot-water) phase but attained a completely and irrevocably oil-wet state after the steam injection process. Although a more favorable water-wetness was presented at the hot-water condition, the heavy-oil recovery process was challenging due to the mobility contrast between heavy-oil and water. Correspondingly, we substantiated that the use of thermally stable chemicals, including alkalis, ionic liquids, solvents, and nanofluids, could propitiously restore the irreversible wettability. Phase distribution/residual oil behavior in porous media through micromodel study is essential to validate the effect of wettability on heavy-oil recovery. Two types of heavy-oils (450 cP and 111,600 cP at 25oC) were used in glass bead micromodels at steam temperatures up to 200oC. Initially, the glass bead micromodels were saturated with synthesized formation water and then displaced by heavy-oils. This process was done to exemplify the original fluid saturation in the reservoirs. In investigating the phase change effect on residual oil saturation in porous media, hot-water was injected continuously into the micromodel (3 pore volumes injected or PVI). The process was then followed by steam injection generated by escalating the temperature to steam temperature and maintaining a pressure lower than saturation pressure. Subsequently, the previously selected chemical additives were injected into the micromodel as a tertiary recovery application to further evaluate their performance in improving the wettability, residual oil, and heavy-oil recovery at both hot-water and steam conditions. We observed that phase change—in addition to the capillary forces—was substantial in affecting both the phase distribution/residual oil in the porous media and wettability state. A more oil-wet state was evidenced in the steam case rather than in the liquid (hot-water) case. Despite the conditions, auspicious wettability alteration was achievable with thermally stable surfactants, nanofluids, water-soluble solvent (DME), and switchable-hydrophilicity tertiary amines (SHTA)—improving the capillary number. The residual oil in the porous media yielded after injections could be favorably improved post-chemicals injection; for example, in the case of DME. This favorable improvement was also confirmed by the contact angle and surface tension measurements in the heavy-oil/quartz/steam system. Additionally, more than 80% of the remaining oil was recovered after adding this chemical to steam. Analyses of wettability alteration and phase distribution/residual oil in the porous media through micromodel visualization on thermal applications present valuable perspectives in the phase entrapment mechanism and the performance of heavy-oil recovery. This research also provides evidence and validations for tertiary recovery beneficial to mature fields under steam applications.

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Recovery Improvement by Chemical Additives to Steam Injection: Identifying Underlying Mechanisms Through Core and Visual Experiments

10.2118/190083-ms ◽

2018 ◽

Cited By ~ 4

Author(s):

F. A. Bruns ◽

T. Babadagli

Keyword(s):

Steam Injection ◽

Chemical Additives ◽

Underlying Mechanisms

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New Formulation of Tertiary Amines for Thermally Stable and Cost-Effective Chemical Additive: Synthesis Procedure and Displacement Tests for High-Temperature Tertiary Recovery in Steam Applications

SPE Journal ◽

10.2118/201769-pa ◽

2021 ◽

pp. 1-18

Author(s):

Randy Agra Pratama ◽

Tayfun Babadagli

Keyword(s):

Heavy Oil ◽

Phase Distribution ◽

Solid Phase ◽

Steam Injection ◽

Tertiary Amines ◽

Residual Oil ◽

Chemical Additive ◽

Reversible Chemical Reaction ◽

Tertiary Recovery ◽

Phase Surface

Summary A newly formulated chemical additive from a group of amines has been tested and applied to in-situheavy oil thermal recovery. Switchable-hydrophilicity chemical additives were successfully synthesized from N,N-dimethylcyclohexylamine in the form of homogeneous and hydrophilic solution. Fundamentally, tertiary amines comprise functional groups of hydrophilic and hydrophobic components. These unique features enable this chemical additive to wet both water and heavy oil, yielding potential interfacial tension (IFT) improvement. Furthermore, the reversible chemical reaction of this chemical additive yields both positive and negative ions. An ion pair formed due to the adsorption of cations—[C8H17NH+]—on the surface of heavy oil, whereas the anions—[HCO3−]—promoted solid-phase surface charge modification, therefore, resulting in the repulsive forces between heavy oil and the rock surface—substantially improving water-wetness and restoring an irreversible wettability alteration due to the phase change phenomenon during steam injection. In this research, two types of heavy oil acquired from a field in western Alberta encompassing the viscosity of 5,616 and 46,140 cp at 25°C was utilized in each experiment. All experiments were performed and measured at high-pressure, high-temperature (HPHT) steam conditions up to 200 psi and 200°C. We perceived that favorable IFT reduction was achieved, and irreversible wettability could be restored after combining switchable-hydrophilicity tertiary amines (SHTA) with steam as a result of the solid-phase surface charge modification to be more negatively charged. Phase distribution/residual oil in the porous media developed after steam injection was able to be favorably recovered, indicating that capillary forces could be reduced. Consequently, more than 80% of the residual oil could be recuperated post-SHTA injection, presenting favorable oil recovery performance. In addition to this promising evidence, SHTA could be potentially recovered by switching its reversible chemical reaction to be in hydrophobic form, hence, promoting this chemical additive to be both reusable and more economically effective. Comprehensive studies and analyses on interfacial properties, phase distribution in porous media, and recovery performance exhibit essential points of view in further evaluating the potential of SHTA for tertiary recovery improvement. Valuable substantiations and findings provided by our research present useful information and recommendations for fields with steam injection applications.

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