A Model for Interfacial Activity of Acidic Crude Oil/Caustic Systems for Alkaline Flooding

1983 ◽  
Vol 23 (04) ◽  
pp. 602-612 ◽  
Author(s):  
T.S. Ramakrishnan ◽  
D.T. Wasan
Keyword(s):  
Crude Oil ◽  
Equilibrium Constants ◽  
Active Species ◽  
Acid Number ◽  
Residual Oil ◽  
Oil Saturation ◽  
Interfacial Activity ◽  
Batch System ◽  
Injection Water ◽  
System Chemistry

Abstract The interaction of the alkali in floodwater and the acids in reservoir crude results in the in-situ formation of surfactants, which are responsible for the lowering of interfacial tension (IFT) in caustic flooding. The extent to which IFT is lowered depends on the specific properties of the crude oil and the injection water. Therefore, it is properties of the crude oil and the injection water. Therefore, it is important to establish the relationship between IFT and the essential chemical properties of the acidic oil and the floodwater. This paper presents such a relationship. presents such a relationship. In this discussion, the adsorption and the desorption of the active species at the interface are modeled as ionic processes using the Gouy-Chapman theory of the diffuse double layer. The interfacial potentials calculated using this model show a fair agreement with the potentials calculated using this model show a fair agreement with the experimentally measured trend of electrophoretic mobility. Also, the model rationalizes the experimentally observed effects of alkali concentration, salinity, and the oleic- to aqueous-phase ratio on IFT. We conclude that the acid number of the crude oil may not correlate directly with interfacial activity. Even in cases of low-acid-number crudes, significant interfacial activity could be obtained because of highly hydrophobic active species in the crude. Introduction IFT in acidic crude/alkali systems plays an important role in EOR with alkaline agents. The extent-and probably the mechanism-of oil recovery is highly dependent on the degree to which IFT is lowered in such systems. Because it is possible to estimate the residual oil saturation from capillary number, and hence the IFT through a suitable displacement model, there is a necessity for quantitative evaluation of IFT in an alkaline flooding process. Although it is widely accepted that surfactants are generated by reaction in caustic flooding of acidic crude reservoirs, there have been few attempts to develop a chemistry and relate it to the IFT attained in these systems. A relationship between equilibrium IFT and NaOH concentration (restricted here to caustic) in a batch system permits comparison with experimental data, and hence evaluation of system parameters such as equilibrium constants. Also, from these parameters, an parameters such as equilibrium constants. Also, from these parameters, an equilibrium flow model can be solved for the concentration of chemical agents in place in caustic flooding. The IFT and hence the residual oil saturation can then be calculated in a flow process, on the basis of the batch relationship. This study, by rationalizing the observations of IFT in acidic crude/caustic systems, permits evaluation of the equilibrium constants and the other necessary parameters. The model also reveals the dependence of interfacial potential on variables such as NaOH and NaCl concentrations. Model Description The rationalization of the interfacial activity between the acidic crude oil and caustic solution is based on a simple system chemistry. The proposed system chemistry has been used to solve for the interfacially proposed system chemistry has been used to solve for the interfacially active species in a batch system. Considering adsorption and desorption kinetics at the interface, along with a suitable theoretical description of the electrical double layer, we derived the adsorption isotherm for the active species. The interfacial activity (i.e., the reduction in IFT of the system) was then directly calculated by the Gibbs equation for adsorption at the interface. An alternative method using an equivalent equation of state (EOS) is also presented. To keep mathematics tractable and the physics simple, the formation of micelles is not considered. Only an equilibrium study is conducted here, and it is applicable primarily to an equilibrium flow model. SPEJ p. 602

scholarly journals Simulation of Surfactant Oil Recovery Processes and the Role of Phase Behaviour Parameters

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 983 ◽  
Author(s):  
Pablo Druetta ◽  
Francesco Picchioni
Keyword(s):  
Oil Recovery ◽  
Phase Behaviour ◽  
Residual Oil ◽  
Two Phase ◽  
Oil Saturation ◽  
Recovery Processes ◽  
Fluid Properties ◽  
Injection Water ◽  
Finitedifference Method

Chemical Enhanced Oil Recovery (cEOR) processes comprise a number of techniques whichmodify the rock/fluid properties in order to mobilize the remaining oil. Among these, surfactantflooding is one of the most used and well-known processes; it is mainly used to decrease the interfacialenergy between the phases and thus lowering the residual oil saturation. A novel two-dimensionalflooding simulator is presented for a four-component (water, petroleum, surfactant, salt), two-phase(aqueous, oleous) model in porous media. The system is then solved using a second-order finitedifference method with the IMPEC (IMplicit Pressure and Explicit Concentration) scheme. The oilrecovery efficiency evidenced a strong dependency on the chemical component properties and itsphase behaviour. In order to accurately model the latter, the simulator uses and improves a simplifiedternary diagram, introducing the dependence of the partition coefficient on the salt concentration.Results showed that the surfactant partitioning between the phases is the most important parameterduring the EOR process. Moreover, the presence of salt affects this partitioning coefficient, modifyingconsiderably the sweeping efficiency. Therefore, the control of the salinity in the injection water isdeemed fundamental for the success of EOR operations with surfactants.

Simulation of Residual oil Saturation in Near-miscible gas Flooding Through Saturation-dependent Tuning of the Equilibrium Constants

2014 ◽  
Author(s):  
Leonardo Patacchini ◽  
Sebastien Duchenne ◽  
Marcel Justin Bourgeois ◽  
Arthur Moncorge ◽  
Quentin Pallotta
Keyword(s):  
Equilibrium Constants ◽  
Residual Oil ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Gas Flooding

Correlation and Prediction of Residual Oil Saturation for Gas Injection EOR Processes

1998 ◽  
Vol 1 (02) ◽  
pp. 127-133 ◽  
Author(s):  
E.A. Lange
Keyword(s):  
Interfacial Tension ◽  
Crude Oil ◽  
Gas Injection ◽  
Solubility Parameters ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Hydrocarbon Gases ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Eor Processes

Abstract A promising correlation has been developed that can be used to predict miscible or near-miscible residual oil saturation, Sorm, for a wide range of injected gases, crude oils, temperature, and pressure conditions. The correlation is based on representation of the chemical and physical properties of the crude oil and the injected gas through Hildebrand solubility parameters. This approach has the advantage that characteristics of both the injected gas and crude oil are included in the correlation, in contrast to correlations based solely on properties of the injected gas. The correlation was developed using available experimental data for tertiary recovery of eight crude oils in carbonate and sandstone cores with common EOR gases (CO2, N2, CH4, CH4 + liquefied petroleum gas). Results for 45 coreflood tests at reservoir conditions collapsed along a band when Sorm was plotted as a function of the difference in solubility parameter between the injected gas and the crude oil. Results for a pure oil, decane, with CO2 lay along the same band. The success of this correlation scheme may be due to the basic characterization of the fluids and to a relationship between solubility parameters and interfacial tension. Use of the correlation requires knowledge of only injected gas composition, injected gas density, oil average molecular weight, and temperature. This empirical correlation should have utility in screening studies or in process simulation as a simple means to forecast residual oil saturations as measured in coreflood tests. The correlation can be used to predict roughly the effects of changes in pressure, temperature, or injected gas composition on residual oil saturation. A new method to predict minimum miscibility pressure based on the solubility parameter concept is also described. Introduction The miscible residual oil saturation, Sorm, is a key property for simulation and screening studies of gas injection EOR processes. This property represents the oil saturation remaining in a porous media after injection of a large bank of a high pressure gas, such as CO2, N2, or CH4, after a waterflood. The miscible residual oil saturation thus represents the local displacement efficiency of oil by the injected gas in a ternary system of oil, gas, and water. Injected gases are frequently supercritical fluids, and proposed mechanisms of oil recovery include low interfacial tension displacement, extraction, and oil swelling. Within the industry, a common parameter used in design of these processes is the minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME) level for hydrocarbon gases as determined from sandpack slim-tube tests. Recent work has suggested use of reservoir-condition coreflood data in design of gas injection EOR processes instead of MMP or MME levels. Miscible recovery processes have been studied extensively, and a variety of schemes have been developed to predict MMP. In contrast to the large number of predictive schemes for MMP, few methods have been proposed to predict Sorm. Use of a capillary number correlation has been suggested, but this approach requires knowledge of interfacial tension between equilibrated phases. A correlation of residual oil saturation with pore structure in carbonates has been suggested as well as correlations of Sorm with reduced density of the injected gas for one crude oil with several hydrocarbon gases. Although interesting, these approaches do not meet the need for a general method to predict Sorm for any injected gas and any crude oil, and laboratory coreflood tests at reservoir conditions are usually recommended to determine this important measure of local displacement efficiency.

A New Method of Fall-Off Test in Water Injection Well in Tahe Oilfield

2013 ◽  
Vol 807-809 ◽  
pp. 2508-2513
Author(s):  
Qiang Wang ◽  
Wan Long Huang ◽  
Hai Min Xu
Keyword(s):  
Water Injection ◽  
Injection Well ◽  
Well Test ◽  
Well Bore ◽  
Residual Oil ◽  
Injection Wells ◽  
Oil Saturation ◽  
Tahe Oilfield ◽  
Fitting Method ◽  
Front Radius

In pressure drop well test of the clasolite water injection well of Tahe oilfield, through nonlinear automatic fitting method in the multi-complex reservoir mode for water injection wells, we got layer permeability, skin factor, well bore storage coefficient and flood front radius, and then we calculated the residual oil saturation distribution. Through the examples of the four wells of Tahe oilfield analyzed by our software, we found that the method is one of the most powerful analysis tools.

Studying demulsifier reactants for crude oil processing facilities

2021 ◽  
pp. 90-104
Author(s):  
L. V. Taranova ◽  
A. G. Mozyrev ◽  
V. G. Gabdrakipova ◽  
A. M. Glazunov
Keyword(s):  
Crude Oil ◽  
Bottom Water ◽  
Oil Content ◽  
Optimal Consumption ◽  
Residual Oil ◽  
Well Production ◽  
Oil Processing ◽  
Water Cut ◽  
Required Quality

The article deals with the issues of improving the quality of highly watered well production fluid processing using chemical demulsifier reactants at crude oil processing facilities; the analysis of the use of the reactants at the Samotlor field has been made. The article presents the results of the study of the effectiveness of the "Hercules 2202 grade A" and "SNPH-4460-2" demulsifiers in comparison with the indicators of oil and bottom water processing achieved in the presence of the reactants used at existing facilities; their optimal consumption has been determined. The study has shown that the selected demulsifiers provide the required quality of the oil and water under processing at the considered oil processing facilities and can be used along with the basic reactants for these facilities. On the basis of total indicators, the best results have been achieved using "Hercules 2202 grade A" with the improved indicators of water cut and residual oil content in water by 33.9 % and 2.8 % while reducing the reactant consumption by 9.7 % compared to the basic demulsifier.

Enhancing Rheological Properties and Reduction of Total Acid Number of a Heavy Crude Oil Using Ethanol and Trona

2021 ◽  
Author(s):  
Ahmed Almadhaji ◽  
Mohammed Saeed ◽  
Hitham Ibrahim ◽  
Anas Ahmed ◽  
Ragaei Maher
Keyword(s):  
Crude Oil ◽  
Rheological Properties ◽  
Kinematic Viscosity ◽  
Acid Number ◽  
Capillary Viscometer ◽  
Heavy Crude Oil ◽  
Production Operation ◽  
Total Acid ◽  
Total Acid Number ◽  
Heavy Crude

Abstract One of Sudanese fields has a heavy crude oil which has a high Total Acid Number (TAN) and high viscosity, can cause a lot of problems in production operation, transport, and storage facilities. The effect of ethanol dilution on the rheological properties of crude (especially the kinematic viscosity) was studied and presented. Moreover, the consequence of blending Trona (NaHCO3.Na2CO3) with a specified amount of Ethanol in the crude can reduce (TAN) to acceptable limits for solving corrosion and flowability problems. The approach is based on the experiments and laboratory works on the crude's samples after blending with a certain amount of Trona and Ethanol. It depends on the results of apparatuses, that are used to measure the samples, for instance, Calibrated glass capillary viscometer and ASTM D664 titration volume Total Acid Number tester which are employed to get the values of kinematic viscosity and TAN, respectively. The tests are established with crude have kinematic viscosity (187 cst) at temperature 75°C and TAN almost (8.51). While increasing the dosage of Trona at the ambient temperature (38°C) with the certain mass percentage of Ethanol (5%), TAN is decreased from (8.51 to 4.00 mgKOH/g). Also, the kinematic viscosity is declined from (187 cst to 96.75 cst) after increasing the volume of Ethanol at 75°C. These outcomes indicated that Ethanol could reduce Sudanese heavy crude's viscosity, and the Trona could decrease the TAN. This reduction occurred due to Ethanol dilution. The Ethanol molecules disturb the molecular structure of the crude, which forms polar bond within the hydrocarbon chain that leads to lower the friction between molecules of hydrocarbon in the crude. Also, Trona shrinks TAN because the Hydroxide ions (OH+) that founded in Trona neutralize the Hydrogen ions (H−) in Naphthenic acid in Sudanese heavy crude. This study can be summarized in the ability to solve the difficulty of transporting and processing the heavy crude oil in refineries; maintains the quality of the crude while utilizing it with friendly environmental materials and low cost.

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