Effect of Live Crude on Alkaline/Surfactant Polymer Formulations: Implications for Final Formulation Design

SPE Journal ◽  
2012 ◽  
Vol 17 (02) ◽  
pp. 352-361 ◽  
Author(s):  
Jeffrey G. Southwick ◽  
Yi Svec ◽  
Greg Chilek ◽  
Gordon T. Shahin
Keyword(s):  
Phase Behavior ◽  
Control Experiment ◽  
Screening Tests ◽  
Reservoir Pressure ◽  
Low Interfacial Tension ◽  
Equilibrium Amount ◽  
Paraffinic Crude ◽  
Surfactant Systems ◽  
Crude Emulsion ◽  
Solution Gas

Summary Phase-behavior experiments have identified several surfactant systems that develop high solubilization ratios and low interfacial tension (IFT) with a specific dead paraffinic crude oil at specific salinities. The purpose of this work is to test these surfactant systems with reconstituted live crude. Emulsion-screening tests were performed in sight cells where an equilibrium amount of solution gas is dissolved in the crude at reservoir pressure (1,100 psi). The results indicate that the surfactant is relatively more soluble in the oil phase under these conditions. Thus, a formulated chemical slug for field conditions should contain either less salinity or a more hydrophilic surfactant system than that used in formulations with dead crude. Phase-behavior measurements estimate this offset to be approximately 0.25% less NaCl for the particular live crude in this study. The relevance of this offset is shown by comparing the results of dead-crude corefloods with a live-crude coreflood. A control experiment pressurizing oil with nitrogen at the same condition, 1,100 psi, did not show enhanced relative surfactant solubility in the oil phase.

Modeling of Pressure and Solution Gas for Chemical Floods

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 428-439 ◽  
Author(s):  
M.. Roshanfekr ◽  
R.T.. T. Johns ◽  
M.. Delshad ◽  
G.A.. A. Pope
Keyword(s):  
Phase Behavior ◽  
Oil Recovery ◽  
Atmospheric Pressure ◽  
Carbon Number ◽  
Chemical Flooding ◽  
Reservoir Pressure ◽  
Optimal Salinity ◽  
Free Gas ◽  
Cubic Equation ◽  
Solution Gas

Summary The goal of surfactant/polymer (SP) flooding is to reduce interfacial tension (IFT) between oil and water so that residual oil is mobilized and high recovery is achieved. The optimal salinity and optimal solubilization ratios that correspond to ultralow IFT have recently been shown, in some cases, to be a strong function of the methane mole fraction in the oil at reservoir pressure. We incorporate a recently developed methodology to determine the optimal salinity and solubilization ratio at reservoir pressure into a chemical-flooding simulator (UTCHEM). The proposed method determines the optimal conditions on the basis of density estimates by use of a cubic equation of state (EOS) and measured phase-behavior data at atmospheric pressure. The microemulsion phase-behavior (Winsor I, II, and III) are adjusted on the basis of this predicted optimal salinity and solubilization ratio in the simulator. Parameters for the surfactant phase-behavior equation are modified to account for these changes, and the trend in the equivalent alkane carbon number (EACN) is automatically adjusted for pressure and methane content in each simulation gridblock. We use phase-behavior data from several potential SP floods to demonstrate the new implementation. The implementation of the new phase-behavior model into a chemical-flooding simulator allows for a better design of SP floods and more-accurate estimations of oil recovery. The new approach could also be used to handle free gas that may form in the reservoir; however, the SP-flood simulation when free gas is present is not the focus of this paper. We show that not accounting for the phase-behavior changes that occur when methane is present at reservoir pressure can greatly affect the oil recovery of SP floods. Improper design of an SP flood can lead to production of more oil as a microemulsion phase than as an oil bank. This paper describes the procedure to implement the effect of pressure and solution gas on microemulsion phase behavior in a chemical-flooding simulator, which requires the phase-behavior data measured at atmospheric pressure.

Phase behavior of polymer-surfactant systems in relation to polymer-polymer and surfactant-surfactant mixtures

1993 ◽  
Vol 65 (5) ◽  
pp. 953-958 ◽  
Author(s):  
B. Lindman ◽  
Ali Khan ◽  
E. Marques ◽  
M. Graca da Miguel ◽  
L. Piculell ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Surfactant Mixtures ◽  
Surfactant Systems ◽  
Polymer Surfactant

Phase Behavior of Water/Perchloroethylene/Anionic Surfactant Systems

Langmuir ◽  
1994 ◽  
Vol 10 (4) ◽  
pp. 1146-1150 ◽  
Author(s):  
Jimmie R. Jr. Baran ◽  
Gary A. Pope ◽  
William H. Wade ◽  
Vinitha Weerasooriya
Keyword(s):  
Phase Behavior ◽  
Anionic Surfactant ◽  
Surfactant Systems

Microemulsion Performance Fluids

1989 ◽  
Vol 177 ◽  
Author(s):  
J. Bock ◽  
M. L. Robbins ◽  
S. J. Pace
Keyword(s):  
Phase Behavior ◽  
Single Phase ◽  
Interfacial Area ◽  
Immiscible Fluids ◽  
Proper Selection ◽  
Solubilization Capacity ◽  
Low Interfacial Tension ◽  
Multi Phase ◽  
The Relationship ◽  
Selection Of

ABSTRACTMicroemulsions are thermodynamically stable mixtures of two immiscible fluids, such as oil and water, and one or more surfactants or cosurfactants. These systems have a rich micro-structure and phase behavior which can take the form of a variety of multi-phase and single phase oil- or watercontinuous or bicontinuous fluids with unique and useful properties. The thermodynamic stability, ultra-low interfacial tension, clarity, high solubilization capacity and high interfacial area suggest uses “performance fluids.” The relationship between surfactant ussetsru cfotur reth eansde the phase behavior and properties of microemulsions is the key to their design. Through the proper selection of surfactants, microemulsion phase continuity can be tailored for a variety of applications. Two such applications, coal freeze conditioning and oil spill dispersion, are described in this paper.

Influence of Methane on the Phase Behavior of Oil + Water + Nonionic Surfactant Systems

1998 ◽  
Vol 102 (1) ◽  
pp. 200-205 ◽  
Author(s):  
E. S. J. Rudolph ◽  
M. J. Bovendeert ◽  
Th. W. de Loos ◽  
J. de Swaan Arons
Keyword(s):  
Phase Behavior ◽  
Nonionic Surfactant ◽  
Oil Water ◽  
Surfactant Systems
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