Low Salinity Waterflooding for a Carbonate Reservoir Experimental Evaluation and Numerical Interpretation

2016 ◽  
Author(s):  
Ramez A. Nasralla ◽  
Hilbert A. van der Linde ◽  
Fons H. M. Marcelis ◽  
Hassan Mahani ◽  
Shehadeh K. Masalmeh ◽  
...  
Keyword(s):  
Experimental Evaluation ◽  
Carbonate Reservoir ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Low Salinity Waterflooding for a Carbonate Reservoir in the Middle East: Experimental Evaluation and Numerical Interpretation

2016 ◽  
Author(s):  
Ramez A. Nasralla ◽  
Hilbert A. van der Linde ◽  
Fons H. M. Marcelis ◽  
Hassan Mahani ◽  
Shehadeh K. Masalmeh ◽  
...  
Keyword(s):  
Middle East ◽  
Experimental Evaluation ◽  
Carbonate Reservoir ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Low salinity waterflooding for a carbonate reservoir: Experimental evaluation and numerical interpretation

2018 ◽  
Vol 164 ◽  
pp. 640-654 ◽  
Author(s):  
Ramez A. Nasralla ◽  
Hassan Mahani ◽  
Hilbert A. van der Linde ◽  
Fons H.M. Marcelis ◽  
Shehadeh K. Masalmeh ◽  
...  
Keyword(s):  
Experimental Evaluation ◽  
Carbonate Reservoir ◽  
Low Salinity ◽  
Low Salinity Waterflooding

scholarly journals Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 84-101 ◽  
Author(s):  
Maxim P. Yutkin ◽  
Himanshu Mishra ◽  
Tadeusz W. Patzek ◽  
John Lee ◽  
Clayton J. Radke
Keyword(s):  
Ionic Strength ◽  
Ion Exchange ◽  
Crude Oil ◽  
Surface Charge ◽  
Double Layer ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Diffuse Double Layer ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Summary Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of calcite bulk and surface equilibria draws several important inferences about the proposed LSW oil-recovery mechanisms. Diffuse double-layer expansion (DLE) is impossible for brine ionic strength greater than 0.1 molar. Because of rapid rock/brine equilibration, the dissolution mechanism for releasing adhered oil is eliminated. Also, fines mobilization and concomitant oil release cannot occur because there are few loose fines and clays in a majority of carbonates. LSW cannot be a low-interfacial-tension alkaline flood because carbonate dissolution exhausts all injected base near the wellbore and lowers pH to that set by the rock and by formation CO2. In spite of diffuse double-layer collapse in carbonate reservoirs, surface ion-exchange oil release remains feasible, but unproved.

Wettability Alteration During Low-Salinity Waterflooding in Carbonate Reservoir Cores

2014 ◽  
Author(s):  
Waleed Alameri ◽  
Tadesse Weldu Teklu ◽  
Ramona M. Graves ◽  
Hossein Kazemi ◽  
Ali M AlSumaiti
Keyword(s):  
Carbonate Reservoir ◽  
Wettability Alteration ◽  
Low Salinity ◽  
Low Salinity Waterflooding

scholarly journals Effects of Formation Brine Compositions on Effectiveness of Low Salinity Brine Injection in Carbonate Reservoir

2018 ◽  
Vol 171 ◽  
pp. 04002
Author(s):  
Suthida Meekangwal ◽  
Falan Srisuriyachai
Keyword(s):  
Oil Recovery ◽  
Calcium Ion ◽  
Carbonate Reservoir ◽  
Magnesium Ion ◽  
Rock Surface ◽  
Dissolution Mechanism ◽  
Low Salinity ◽  
Carbonate Formation ◽  
High Calcium ◽  
Low Salinity Waterflooding

Nowadays, Low Salinity Waterflooding (LSWF) is considered as one of the most effective techniques to enhance oil recovery. Essential mechanism is a Multi-Ion Exchange (MIE). In carbonate formation, collaboration of Potential Determining Ions (PDI) with rock surface and crude oil results in adjustment of surface equilibrium. These ions in injected brine are thoroughly investigated but effects from formation brine are not well documented. In this study, ratio of divalent ions including calcium and magnesium ions in formation brine is studied. Results from imbibition test shows that formation brine containing calcium ion to magnesium ion ratio of 1:1 yields response to LSWF. Oppositely, formation brines with high ratios of 10:1 and 15:1 do not respond to LSWF. As calcium ion in connate water diffuses to injected water, high calcium ion will exhibit dissolution mechanism of rock surface which is part of oil recovery mechanisms. Formation brine with high calcium ion is therefore not recommended for LSWF. High portion of magnesium ion in formation brine does not affect effectiveness of LSWF. Dissolution of magnesium from rock may be obstructed but oil can still be liberated from calcium carboxylate complex and dissolution of calcium. Coreflood test shows similar result which confirms previous explanation.

The Effect of Ba2+ & Sr2+ on EOR Efficiency in Carbonate Reservoir During Low Salinity Waterflooding

2017 ◽  
Author(s):  
Hyemin Park ◽  
Yongjun Park ◽  
Yeonkyeong Yeonkyeong ◽  
Joohyung Kim ◽  
Wonsuk Lee ◽  
...  
Keyword(s):  
Carbonate Reservoir ◽  
Low Salinity ◽  
Low Salinity Waterflooding
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