Enhanced Oil Recovery in Unconventional Liquid Reservoir Using a Combination of CO2 Huff-n-Puff and Surfactant-Assisted Spontaneous Imbibition

Author(s):  
Fan Zhang ◽  
Imad A. Adel ◽  
Kang Han Park ◽  
I. W. R. Saputra ◽  
David S. Schechter
2019 ◽  
Vol 33 (8) ◽  
pp. 6904-6920 ◽  
Author(s):  
I Wayan Rakananda Saputra ◽  
Kang Han Park ◽  
Fan Zhang ◽  
Imad A. Adel ◽  
David S. Schechter

2011 ◽  
Vol 25 (4) ◽  
pp. 1697-1706 ◽  
Author(s):  
M. A. Fernø ◽  
R. Grønsdal ◽  
J. Åsheim ◽  
A. Nyheim ◽  
M. Berge ◽  
...  

2021 ◽  
Author(s):  
Shaina Kelly ◽  
◽  
Ron J.M. Bonnie ◽  
Micheal J. Dick ◽  
Dragan Veselinovic ◽  
...  

Matrix wettability is a key driver in relative permeability and, hence, a critical factor controlling imbibition and drainage at UR fracture-matrix interfaces as well as enhanced oil recovery (EOR). In this study, we (1) adapt and apply the NMR-based wettability index (NWI) methodology of Looyestijn et al. (2006) to a variety of unconventional twin samples undergoing, respectively, spontaneous imbibition with oil-displacing-water and water-displacing-oil and (2) compare the robustness of this method among a variety of samples pairs and also to other NMR-based wettability methods. The samples analyzed cover a range of rock types, major formations, maturity and content of organic material. All displayed unique time-lapse wettability profiles and steady state NWI values. This work advances our previous works (Dick et al., 2019; Kelly et al., 2020) on this subject, where the viability of the methodology was established on end-member pilot samples, towards applicability as a UR SCAL method. The NWI methodology predicts T2 spectra using linear combinations (mixing) of “end-point” T2 spectra. The mixing ratios yielding the closest match to the measured spectra are then used to compute a wettability index. These mixing ratios were validated against (1) mass-balance calculations, (2) repeat experiments with heavy water (D2O) instead of H2O and (3) measured T1-T2 maps, enhancing confidence in the robustness of the method. Our comparisons show that alternative approaches representing the T2 spectra through a single mean T2 value or T2 peak-fit, fall short, especially in tight rocks where fast relaxation rate components tend to skew harmonic mean T2 values and also in samples where oil and water peaks are not clearly resolved. Full spectrum-based methods, akin to Looyestijn’s, appear more robust and stable over a much wider range of reservoir conditions. Repeated NMR acquisition throughout our long-term imbibition experiments shows that time-lapse NWI methodology probes the effects of rock properties, saturation changes, and injected fluid chemistry (enhanced oil recovery strategies) on wettability alteration. Additionally, this NWI study quantifies the wide variation in wettability among unconventional samples.


2021 ◽  
pp. 1-18
Author(s):  
Takaaki Uetani ◽  
Hiromi Kaido ◽  
Hideharu Yonebayashi

Summary Low-salinity water (LSW) flooding is an attractive enhanced oil recovery (EOR) option, but its mechanism leading to EOR is poorly understood, especially in carbonate rock. In this paper, we investigate the main reason behind two tertiary LSW coreflood tests that failed to demonstrate promising EOR response in reservoir carbonate rock; additional oil recovery factors by the LSW injection were only +2% and +4% oil initially in place. We suspected either the oil composition (lack of acid content) or the recovery mode (tertiary mode) was inappropriate. Therefore, we repeated the experiments using an acid-enriched oil sample and injected LSW in the secondary mode. The result showed that the low-salinity effect was substantially enhanced; the additional oil recovery factor by the tertiary LSW injection jumped to +23%. Moreover, it was also found that the secondary LSW injection was more efficient than the tertiary LSW injection, especially in the acid-enriched oil reservoir. In summary, it was concluded that the total acid number (TAN) and the recovery mode appear to be the key successful factors for LSW in our carbonate system. To support the conclusion, we also performed contact angle measurement and spontaneous imbibition tests to investigate the influence of acid enrichment on wettability, and moreover, LSW injection on wettability alteration.


2018 ◽  
Vol 15 (3) ◽  
pp. 564-576 ◽  
Author(s):  
Mohammad Reza Zaeri ◽  
Rohallah Hashemi ◽  
Hamidreza Shahverdi ◽  
Mehdi Sadeghi

SPE Journal ◽  
2016 ◽  
Vol 21 (03) ◽  
pp. 0706-0719 ◽  
Author(s):  
Bernard Bourbiaux ◽  
André Fourno ◽  
Quang-Long Nguyen ◽  
Françoise Norrant ◽  
Michel Robin ◽  
...  

Summary Among various ways to extend the lifetime of mature fields, chemical enhanced-oil-recovery (EOR) processes have been subject of renewed interest in the recent years. Oil-wet fractured reservoirs represent a real challenge for chemical EOR because the matrix medium does not spontaneously imbibe the aqueous solvent of chemical additives. The present paper deals with chemical EOR by use of wettability modifiers (WMs). The kinetics of spontaneous imbibition of chemical solutions in oil-wet limestone plugs and mini-plugs was quantified thanks to X-ray computed-tomography (CT) scanning and nuclear-magnetic-resonance (NMR) measurements. Despite the small size of samples and the slowness of experiments, accurate recovery curves were inferred from in-situ fluid-saturation measurements. Scale effects were found quite consistent between mini-plugs and plugs. During a second experimental step, viscous drive conditions were imposed between the end faces of a plug, to account for the possibly significant contribution of fracture viscous drive to matrix oil recovery. The recovery kinetics and behavior, especially the occurrence of countercurrent and cocurrent flow, are interpreted through the analysis of modified forces in the presence of a diffusing or convected WM that alters rock wettability and reduces water/oil interfacial tension (IFT) to a lesser extent. This work calls for an extensive modeling study to specify the conditions on chemical additives and recovery-process implementation that optimize the recovery kinetics.


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