Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water

Transcription

1 Indian Journal of Science and Technology, Vol 9(35), DOI: /ijst/2016/v9i35/88111, September 2016 ISSN (Print) : ISSN (Online) : Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water Abdolmohsen Shabib-Asl *, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour Department of Petroleum Engineering, Universiti Teknologi PETRONAS (UTP), Bandar Seri Iskandar , Tronoh, Perak, Malaysia; msn.shabib@gmail.com, abdalla.ayoub@petronas.com.my, khaled.elraies@petronas.com, noor_hoseini@yahoo.com, hamed.hematpoor@gmail.com Abstract Objectives: To find the surfactant aqueous solution that will ultimately reduce the IFT and form a more stable solution in presence of oil. Methods/Analysis: Each test was performed at 80 o C. The Low Salinity Water (LSW) consisted of thirtyone samples with different ion compositions and concentrations ranging from 500 to 6500 ppm. The surfactant aqueous solutions were prepared by mixing proportions of surfactant with each of the LSW aqueous solutions. For Interfacial Tension (IFT) and Foam Stability Test (FST), two types of crude oil with different Total Acid Number and Total Base Number were used. Findings: The experimental results revealed that for both crude oils A and B, the surfactant solution with LSW composed of monovalent ions of sodium and potassium caused much changes in the IFT and were characterized with stable foam columns as compared to the divalent cations of magnesium, Calcium, as well as the mixture compositions. However, changes for crude oil B (lower TAN and higher TBN) were greater than for crude oil A (higher TAN and lower TBN). Similar results were observed for AST. The formation water presented poor results for all the tests. Novelty/Improvement: This paper is very important in a way that attempts to produce a foam formulation that will remain stable even in the presence of oil; a study never performed before. Moreover, the obtained results are valuable for further lying down the truth behind the effects of LSW on the IFT, AST, and FST. Furthermore, it applies a good approach when using two different types of light crude oils for the IFT and FST. Keywords: Acid Number, Base Number, Interfacial Tension 1. Introduction The practice of injecting fluids into the reservoir for enhancing oil recovery has prevailed for several decades in the petroleum Industry. The fluid may be either a gas or an aqueous solution. One example includes reservoir brine, which consists of dissolved salts. Depending on the composition or concentration of the salt content, various formulations are possible. In the majority of the cases, the addition of surfactant to the aqueous solution is essential for decreasing the interfacial tension (IFT) between injected fluid and the reservoir oil. This, results in an increased mobility of the oil phase. However, as previously stated there are many formulations. Thus, it becomes important to study the effect of each and then select the best ones. In addition, because each solution may have different impacts on the fluid behavior in the reservoir, their meticulous assessment before injection is critical. Apart from decreasing the IFT, surfactants have also earned a good reputation for reducing the gas oil ratio, increasing gas mobility, and improving gas sweep efficiency 1-5. Given their importance, surfactants have been at the core of research for many researchers. One of the most focused point of research is the study of the sensitiveness of the surfactants under reservoir conditions. Here, the fluid system comprises surfactant-brine-gas and oil. Upon injection into the reservoir, the surfactant may remain in the aqueous solution or part of it may break *Author for correspondence

2 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water into foam as it mixes with the injected gas. Foam is an essential phase in reservoir, especially during gas injection. It controls gas mobility and reduces the tendency of gravity overriding. In fact, surfactant performance is inextricably linked to foam generation. However, its existence or stability in the reservoir is limited. Generally, the stability of the foam is unfavorably affected by the increase of the brine salinity. This is due to the increased salt content that decreases the electrostatic double layer or the solubility of surfactant in the aqueous phase. Bansal and Shah 6, have also performed a study whereby they attempted to observe the effects of monovalent and divalent ions in aqueous solution with surfactant. The authors reported an increase in values of IFT with the increase of concentration of the divalent cations of magnesium Chloride (MgCl 2 ) and calcium chloride (CaCl 2 ) in connate water 6. Aqueous Stability Test (AST) and Foam Stability Test (FST) are widely performed in laboratories. The main objective of aqueous stability test is to determine the solution that will form with the surfactant a stable and clear solution. If the solution forms precipitate, it may clog the pore throats of the reservoir rocks or create a non-uniform distribution, which results in an ineffective recovery or reservoir damage. Whereas, the foam stability test determines within which formulation the created foam column lasts longer. Various studies on the foam stability have been performed with regard to aqueous solution and surfactant only and none has been attempted to perform the test with oil. Furthermore, it is also important to consider the effectiveness of foams for mobility control in the presence of oil. For an effective mobility control, it is required that the foam reduces the mobility of the displacing fluid. However, this is not the case for oil saturations of about 5 to 20%. Here, the oil becomes detrimental to foam 7. This paper is very important in a way that it attempts to find a foam formulation that will remain stable even in the presence of oil at lowest salinity. In addition, the obtained results are valuable for further lying down the truth behind the effects of LSW on the IFT, AST, and FST. Moreover, it applies a good approach when using two different types of light crude oils for the IFT and FST tests. 2. Materials and Methods 2.1 Materials The Brine In this study, two types of brine were used, the formation Water (FW) and Low salinity Water (LSW). The formation was composed of the calcium ions (Ca 2+ ), Magnesium ions (Mg 2+ ), potassium ions (K + ), sodium ions (Na + ), chloride ions (Cl - ), hydrogen carbonate ions (HCO 3- ), and sulfate ions (SO 4 2- ) with high concentration of Ca 2+ and Mg 2+ ions. It was prepared by dissolving the salts in distilled water. Low Salinity Water (LSW) was prepared by mixing distilled water and salts of Na +, K +, Ca 2+, Mg 2+ and a mixture of all. The salt concentrations ranged from 500 ppm to 6500 ppm. Properties and concentrations of all brines are shown in Table Surfactant The Alpha Olefin Sulphonate (AOS) in Liquid state was used as the surfactant agent. Its chemical formula is CnH 2n-1 SO 3 Na(n=14-16) Crude Oil Total acid number (TAN) and Total Base Number (TBN) are important parameters for characterizing the polar components within the crude oil. TAN is the amount of potassium hydroxide (KOH) in milligrams, required for neutralizing a unit gram of the petroleum acid in the crude oil, Whereas, the TBN is the amount of (KOH) in milligrams, required for neutralizing a unit gram of the petroleum base in crude oil Two samples of crude oil designated as crude oil A and B were used. Their specific total acid and base numbers were measured with reference to the TAN ASTM D664 and TBN ASTM D2896 standard methods by the use of METTLER TOLEDO Potentiometric Titrator. The results are summarized in the Tables 2 and 3. From the tables, it is evident that crude oil A has higher TAN and lower TBN as compared to crude oil B that has lower TAN and higher TBN. 2.2 Method The preparation of surfactant is greatly dependent on the activity of the surfactant feedstock, the desired weight percent of the stock solution, and the calculated critical micelle concentration. In this study, the first task entailed the dilution of surfactant with deionized water to a 10 wt% AOS stock solution with 100% activity. The second task consisted of Surfactant Aqueous Solution (SAS) preparation by mixing proportionate ratios of 0.5% wt, 1%wt and 1.5%wt of surfactant solution from stock solution with each of the LSW and FW compositions. The exact ratio of surfactant to LSW depends on the expected results or phase behavior. The SAS were used for Interfacial tension test (IFT), Aqueous Stability Test 2 Vol 9 (35) September Indian Journal of Science and Technology

3 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour Table 1. Brine composition and concentration Composition Name Na + Ca 2+ Mg 2+ K + HCO 3 - SO 4 2- Cl - TDS ph at 24 o C ph at 80 o C Ionic Strength (mole/l) LSW-1 (NaCl) LSW-2 (NaCl) LSW-3 (NaCl) LSW-4 (NaCl) LSW-5 (NaCl) LSW-6 (NaCl) LSW-7 (CaCl 2 ) LSW-8 (CaCl 2 ) LSW-9 (CaCl 2 ) LSW-10 (CaCl 2 ) LSW-11 (CaCl 2 ) LSW-12 (CaCl 2 ) LSW-13 (MgCl 2 ) LSW-14 (MgCl 2 ) LSW-15 (MgCl 2 ) LSW-16 (MgCl 2 ) LSW-17 (MgCl 2 ) LSW-18 (MgCl 2 ) LSW-19 (KCl) LSW-20 (KCl) LSW-21(KCl) LSW-22 (KCl) LSW-23 (KCl) LSW-24 (KCl) LSW-25 (Mix) LSW-26 (Mix) LSW-27 (Mix) LSW-28 (Mix) LSW-29 (Mix) LSW-30 (Mix) FW Most (Ca 2+ &Mg 2+ ) Vol 9 (35) September Indian Journal of Science and Technology 3

4 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water (AST), and Foam Stability Test (FST) as well as for core flooding experiments Aqueous Stability Test (AST) The main objective of aqueous stability test is to determine the solution that will form with the surfactant a stable and clear mixture. If the solution forms precipitate, it may clog the pore throats of the reservoir rock or create a non-uniform distribution which results in ineffective recoveries or damaging the reservoir. For this work, the AST test was conducted as follows; first, small test tubes of 10ml were cleaned and dried in the oven. Next, for preparing 8 ml of Surfactant Aqueous Solution, the AOS from Stock solution were mixed to each LSW and FW by using mechanical micropipette. As mentioned earlier, it was based on the specific solution calculation. Then, the results were observed and recorded at room temperature. After that, the test tubes were placed in the oven at 80 o C. Finally, the results were checked and recorded after each 6, 12, and 24 hours, all at 80 o C. Figure 1 shows some results from the AST test. The best formulation is that forming a clear solution. While those forming precipitates at the bottom of the tubes or cloudy solutions throughout the tubes are considered as the least stable formulations. Table 2. oil A TAN (mgkoh/g) Table 3. oil B Total Acid and Base Number of the crude TBN (mgkoh/g) Density (g/ cm3) Viscosity 250C Viscosity 850C TAN (mgkoh/g) Total Acid and Base Number of the crude TBN (mgkoh/g) Density (g/ cm3) Viscosity 250C Viscosity 850C Foam Stability Test (FST) The foam stability test determines within which formulation the created foam column is more stable. Various studies on the foam stability have been performed with regard to aqueous solution and surfactant only and none attempted to perform the test with oil. In this work, the FST is conducted with and without oil. This implies for us to choose either the 1wt% or 1.5 wt% AOS. The 1.5wt% AOS, does indeed generate a stronger foam; nevertheless, taking into account the cost, it is eliminated. Therefore, we consider the 1wt% AOS of SAS for the proceeding tests. The procedures for the case of without oil are as follows; first, the test tubes were cleaned and dried in the oven. Second, by employing mechanical micropipette the specific ratio of AOS surfactant solution from stock solution and LSW for 8 ml were conducted into a test tube. The test tubes were immediately shaken until there was no liquid inside the tube or until no foam could be generated. Then, the initial foam heights were measured and recorded at that specific time and temperature (room temperature). Next, the test tubes were placed in the oven at 80 o C. Finally, the foam heights were measured and recorded in fixed intervals of time at 80 o C. The above procedures were also applied when performing the test with both crude oils A and B. The only difference is that for this time instead of mixing just surfactant and LSW, we add 1ml of oil for each formulation. Figure 2 shows the foam columns of the FST test with and without oil Interfacial Tension (IFT) IFT test was performed with the objective of finding the minimum Interfacial Tension (IFT). The IFT was measured by the spinning drop method. In this method, small drop of a sample is injected inside a thin tube already containing another liquid. The tube is then rotated at a high Figure 1. Typical results of an AST test. Figure 2. FST without oil (left) and FST with oil (right). 4 Vol 9 (35) September Indian Journal of Science and Technology

5 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour speed and the interfacial surface tension is calculated from the angular speed of the tube and the shape of the drop. Figure 3 depicts a typical experimental setup for the IFT test. 3. Results and Discussions 3.1 Aqueous Stability Test (AST) As previously stated, the main objective of aqueous stability test is to determine the solution that will form with the surfactant a stable and clear solution. If the solution forms precipitate, it may clog the pore throats of the reservoir rocks or create a non-uniform distribution, which results in an ineffective recovery or reservoir damage. This allows the choice of the best SAS concentration for the other tests. Tables 4, 5, and 6 summarize the results obtained from this test at 1.5wt%, 1wt%, and 0.5wt% concentration of AOS, respectively. From Table 4, for the whole span of 24 hours and all concentration range ( ppm), the compositions of NaCl +1.5%wt AOS and KCl+1.5% AOS form a clear and stable solution. Similar results were verified when the surfactant concentration was decreased to 1%wt and 0.5%wt, as shown in Tables 5 and 6, respectively. This is essentially good and is in line with the above presented objective of the AST test. Thus, we may expect these compositions not to form any precipitates upon injection in the reservoir. However, the remaining compositions exhibit a different trend. They are sensitive to changes of surfactant and LSW concentrations. At 500 ppm LSW and 1.5% AOS (Table 4), the CaCl 2 composition forms a clear solution for the whole span of 24 hours. At 1000 ppm, it starts by forming a slightly cloudy solution that slowly disappears up to 6 hours where it forms a clear solution. This state remains for the next 18 hours, i.e., up to 24 hours. At 2500, 3500, and 4500 ppm, the solutions are cloudy for the first 6 hours and precipitation occurs from 12 to 24 hours. Finally, at 6500 ppm, the solution is cloudy in the Figure 3. Typical laboratory setup for the IFT test. first hours and precipitates from 6 to 24 hours. At 1%wt AOS (Table 5), the scenario is rather different. The CaCl 2 composition forms a clear solution at both 500 and 1000 ppm LSW for the whole period of 24 hours. At 2500 and 3500 ppm LSW, it forms a cloudy solution for the first 12 hours. Then precipitates start to drop at the bottom until 24 hours. At 4500 and 6500ppm LSW, the solution is cloudy for the first 6 hours and precipitation starts to increase gradually up to 24 hours. At 500 and 1000 ppm of 0.5%wt AOS (Table 6), the CaCl 2 composition remains stable by forming a clear solution. At 2500, 3500, 4500, and 6500 ppm, the solutions are cloudy for the first 12 hours and the whole concentration range. From 12 to 24 hours, the solutions at 3500, 4500, and 6500 ppm LSW form precipitates and that at 2500 ppm remains cloudy. At 500 and 1000ppm, the trend exhibited by the MgCl %wt AOS Composition is similar to that of CaCl %wt AOS for the same concentrations. At 2500ppm, the solution is cloudy for the first 6 hours and gradually becomes clear up to 12 hours and continuing to 24 hours. At 3500, 4500, and 6500 ppm, the solution is cloudy for the whole span of 24 hours. At 1%wt AOS, the MgCl 2 composition forms a clear solution at LSW concentrations of 500 and 1000 ppm for the whole time interval. At 2500 ppm, the solution is cloudy for the first 6 hours and slowly becomes clear until 12 hours and remaining up to 24 hours. However, at 3500, 4500, and 6500 ppm, the solutions are cloudy for the first 12 hours and gradually become clear up to 24 hours. These results are the same for the case of 0.5% AOS except that at 2500 and 3500 ppm, the solutions become clear in the first 6 and 12 hours, respectively. The Mix+1.5% AOS composition show a rather complicated trend. At 500, 1000, and 3500 ppm, the solution is clear for the whole 24 hours. However, at 2500, 4500, and 6500 ppm, the solutions are moderately cloudy for the first hours. The cloudiness increases up to 6 hours where they become completely cloudy. Starting from 6 hours the cloudiness decreases until forming a clear solution at 12 hours that remains up to 24 hours. At 1% AOS and 500, 1000 and 3500 ppm LSW, the solutions are clear for the whole time interval of 24 hours. At 2500 and 4500 ppm LSW, the solutions are slightly cloudy in the beginning and become clear from the first 6 hours until 24 hours. At 6500 ppm, the solutions are slightly cloudy in the beginning and become cloudy in the first 6 hours. Then, the cloudiness decreases slowly until Vol 9 (35) September Indian Journal of Science and Technology 5

6 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water Table 4. AST test results for 1.5%wt AOS Components 0 hr (room tem.) 6 hr (80 c) 12 hr (80 c) 24 hr (80 c) LSW-1 (NaCl) 500 ppm+ 1.5% AOS Clear Clear Clear Clear LSW-2 (NaCl) 1000 ppm+ 1.5% AOS Clear Clear Clear Clear LSW-3 (NaCl) 2500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-4 (NaCl) 3500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-5 (NaCl) 4500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-6 (NaCl) 6500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-7 (CaCl 2 ) 500 PPM+ 1.5% AOS Clear Clear Clear Clear LSW-8 (CaCl 2 ) 1000 PPM+ 1.5% AOS Slightly Cloudy Clear Clear Clear LSW-9 (CaCl 2 ) 2500 PPM + 1.5% AOS Cloudy Cloudy Precipitation Precipitation LSW-10 (CaCl 2 ) 3500 ppm+ 1.5% AOS Cloudy Cloudy Precipitation Precipitation LSW-11 (CaCl 2 ) 4500 ppm + 1.5% AOS Cloudy Cloudy Precipitation Precipitation LSW-12 (CaCl 2 ) 6500 ppm + 1.5% AOS Cloudy Precipitation Precipitation Precipitation LSW-13 (MgCl 2 ) 500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-14 (MgCl 2 ) 1000 ppm + 1.5% AOS Slightly Cloudy Clear Clear Clear LSW-15 (MgCl 2 ) 2500 ppm + 1.5% AOS Cloudy Cloudy Clear Clear LSW-16 (MgCl 2 ) 3500 ppm + 1.5% AOS Cloudy Cloudy Cloudy Cloudy LSW-17 (MgCl 2 ) 4500 ppm + 1.5% AOS Cloudy Cloudy Cloudy Cloudy LSW-18 (MgCl 2 ) 6500 ppm + 1.5% AOS Cloudy Cloudy Cloudy Cloudy LSW-19 (KCl) 500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-20 (KCl) 1000 ppm + 1.5% AOS Clear Clear Clear Clear LSW-21(KCl) 2500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-22 (KCl) 3500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-23 (KCl) 4500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-24 (KCl) 6500 ppm + 1.5% AOS Clear Clear Clear Clear LSW-25 (Mix) 500 PPM+1.5% AOS Clear Clear Clear Clear LSW-26 (Mix) 1000PPM + 1.5% AOS Clear Clear Clear Clear LSW-27 (Mix) 2500 PPM + 1.5% AOS Slightly Cloudy Cloudy Clear Clear LSW-28 (Mix) 3500 PPM + 1.5% AOS Clear Clear Clear Clear LSW-29 (Mix) 4500 PPM + 1.5% AOS Slightly Cloudy Cloudy Clear Clear LSW-30 (Mix) 6500 PPM + 1.5% AOS Slightly Cloudy Cloudy Clear Clear FW Most (Ca 2+ &Mg 2+ )+ 1.5% AOS Cloudy Precipitation Precipitation Precipitation 6 Vol 9 (35) September Indian Journal of Science and Technology

7 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour Table 5. AST test results (1%wt AOS) Components 0 hr (room tem.) 6 hr (80 c) 12 hr (80 c) 24 hr (80 c) LSW-1 (NaCl) 500 ppm+ 1% AOS Clear Clear Clear Clear LSW-2 (NaCl) 1000 ppm+ 1% AOS Clear Clear Clear Clear LSW-3 (NaCl) 2500 ppm + 1% AOS Clear Clear Clear Clear LSW-4 (NaCl) 3500 ppm + 1% AOS Clear Clear Clear Clear LSW-5 (NaCl) 4500 ppm + 1% AOS Clear Clear Clear Clear LSW-6 (NaCl) 6500 ppm + 1% AOS Clear Clear Clear Clear LSW-7 (CaCl 2 ) 500 PPM+ 1% AOS Clear Clear Clear Clear LSW-8 (CaCl 2 ) 1000 PPM+ 1% AOS Clear Clear Clear Clear LSW-9 (CaCl 2 ) 2500 PPM + 1% AOS Cloudy Cloudy Cloudy Precipitation LSW-10 (CaCl 2 ) 3500 ppm+ 1% AOS Cloudy Cloudy Cloudy Precipitation LSW-11 (CaCl 2 ) 4500 ppm + 1% AOS Cloudy Cloudy Precipitation Precipitation LSW-12 (CaCl 2 ) 6500 ppm + 1% AOS Cloudy Cloudy Precipitation Precipitation LSW-13 (MgCl 2 ) 500 ppm + 1% AOS Clear Clear Clear Clear LSW-14 (MgCl 2 ) 1000 ppm + 1% AOS Clear Clear Clear Clear LSW-15 (MgCl 2 ) 2500 ppm + 1% AOS Cloudy Cloudy Clear Clear LSW-16 (MgCl 2 ) 3500 ppm + 1% AOS Cloudy Cloudy Cloudy Clear LSW-17 (MgCl 2 ) 4500 ppm + 1% AOS Cloudy Cloudy Cloudy Clear LSW-18 (MgCl 2 ) 6500 ppm + 1% AOS Cloudy Cloudy Cloudy Clear LSW-19 (KCl) 500 ppm + 1% AOS Clear Clear Clear Clear LSW-20 (KCl) 1000 ppm + 1% AOS Clear Clear Clear Clear LSW-21(KCl) 2500 ppm + 1% AOS Clear Clear Clear Clear LSW-22 (KCl) 3500 ppm + 1% AOS Clear Clear Clear Clear LSW-23 (KCl) 4500 ppm + 1% AOS Clear Clear Clear Clear LSW-24 (KCl) 6500 ppm + 1% AOS Clear Clear Clear Clear LSW-25 (Mix) 500 PPM+1% AOS Clear Clear Clear Clear LSW-26 (Mix) 1000PPM + 1% AOS Clear Clear Clear Clear LSW-27 (Mix) 2500 PPM + 1% AOS Slightly Cloudy Clear Clear Clear LSW-28 (Mix) 3500 PPM + 1% AOS Clear Clear Clear Clear LSW-29 (Mix) 4500 PPM + 1% AOS Slightly Cloudy Clear Clear Clear LSW-30 (Mix) 6500 PPM + 1% AOS Slightly Cloudy Cloudy Clear Clear FW Most (Ca 2+ &Mg 2+ )+ 1% AOS Cloudy Precipitation Precipitation Precipitation Vol 9 (35) September Indian Journal of Science and Technology 7

8 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water Table 6. AST test results (0.5%wt AOS) Components 0 hr (room tem.) 6 hr (80 c) 12 hr (80 c) 24 hr (80 c) LSW-1 (NaCl) 500 ppm+ 0.5% AOS Clear Clear Clear Clear LSW-2 (NaCl) 1000 ppm+ 0.5% AOS Clear Clear Clear Clear LSW-3 (NaCl) 2500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-4 (NaCl) 3500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-5 (NaCl) 4500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-6 (NaCl) 6500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-7 (CaCl 2 ) 500 PPM+ 0.5% AOS Clear Clear Clear Clear LSW-8 (CaCl 2 ) 1000 PPM+ 0.5% AOS Clear Clear Clear Clear LSW-9 (CaCl 2 ) 2500 PPM + 0.5% AOS Cloudy Cloudy Cloudy Cloudy LSW-10 (CaCl 2 ) 3500 ppm+ 0.5% AOS Cloudy Cloudy Cloudy Precipitation LSW-11 (CaCl 2 ) 4500 ppm + 0.5% AOS Cloudy Cloudy Cloudy Precipitation LSW-12 (CaCl 2 ) 6500 ppm + 0.5% AOS Cloudy Cloudy Cloudy Precipitation LSW-13 (MgCl 2 ) 500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-14 (MgCl 2 ) 1000 ppm + 0.5% AOS Clear Clear Clear Clear LSW-15 (MgCl 2 ) 2500 ppm + 0.5% AOS Cloudy Clear Clear Clear LSW-16 (MgCl 2 ) 3500 ppm + 0.5% AOS Cloudy Cloudy Clear Clear LSW-17 (MgCl 2 ) 4500 ppm + 0.5% AOS Cloudy Cloudy Cloudy Clear LSW-18 (MgCl 2 ) 6500 ppm + 0.5% AOS Cloudy Cloudy Cloudy Clear LSW-19 (KCl) 500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-20 (KCl) 1000 ppm + 0.5% AOS Clear Clear Clear Clear LSW-21(KCl) 2500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-22 (KCl) 3500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-23 (KCl) 4500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-24 (KCl) 6500 ppm + 0.5% AOS Clear Clear Clear Clear LSW-25 (Mix) 500 PPM+0.5% AOS Clear Clear Clear Clear LSW-26 (Mix) 1000PPM + 0.5% AOS Clear Clear Clear Clear LSW-27 (Mix) 2500 PPM + 0.5% AOS Clear Clear Clear Clear LSW-28 (Mix) 3500 PPM + 0.5% AOS Clear Clear Clear Clear LSW-29 (Mix) 4500 PPM + 0.5% AOS Slightly Cloudy Clear Clear Clear LSW-30 (Mix) 6500 PPM + 0.5% AOS Slightly Cloudy Clear Clear Clear FW Most (Ca 2+ &Mg 2+ )+ 0.5% AOS Cloudy Cloudy Precipitation Precipitation 8 Vol 9 (35) September Indian Journal of Science and Technology

9 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour becoming clear at 12 hours. The solution remains clear until 24 hours. Finally, at 0.5% AOS and 500, 1000, 2500, and 3500, the solutions are clear for the whole time interval. Nonetheless, at 4500 and 6500 ppm, the solutions are slightly cloudy right in the beginning and become clear in the first 6 hours and remains for 24 hours. From the results, it is obvious that stable conditions (clear solution) of the Surfactant Aqueous Solution (SAS) are obtained at 0.5wt%. However, it is not suitable for the generation of strong foam. Recall that the readiness of foam generation is directly proportional to the surfactant concentration. This implies for us to choose either the 1wt% or 1.5 wt% AOS. The 1.5wt% AOS, does indeed generate a stronger foam; nevertheless, taking into account the cost, it is eliminated. Therefore, we consider the 1wt% AOS for the proceeding tests. Furthermore, with respect to each LSW concentration, the stable conditions were obtained for the whole range of concentrations ( ppm) for the KCl, NaCl, and Mix LSW compositions, at 500 and 1000 ppm for the CaCl 2 composition, and at 500,1000, and 2500ppm for the MgCl 2 composition. Hence, these are the LSW concentrations considered for the next tests. 3.2 FST without Crude Oil (NaCl+1%wt AOS) Figure 4 is representative of the changes of foam column with time for the NaCl + 1% AOS solution at concentrations of LSW ranging from 500 to 6500 ppm. From the Figure, obviously the foam columns are continuously decreasing for the whole span of time. At the beginning, the columns are so high and stable. In addition, the composition with 2500 ppm of salinity has the highest height record followed by that at 1000 ppm, then at 500 ppm and finally at 2500 ppm. However, in the first 40 minutes, these columns decrease significantly. Here, the highest foam column is achieved by the composition at 500 ppm, then at 1000 ppm, 2500 ppm, 6500 ppm, 4500 and finally 3500ppm. After 2 hours, the trend continued to be constant, that is, the heights decrease further to very small lengths. These columns continue to decrease gradually until no foam columns are observed at the end of 6 and 12 hours. 3.3 FST without Crude Oil (KCl+1%wt AOS) Similarly, for KCl+1%wt AOS trend is almost the same as for the NaCl+1%wt AOS case above. As shown in Figure 5, the foam columns are very stable and high right in the beginning of the test. Here, the highest foam column is achieved by the 500 ppm composition followed by the 1000 ppm, then 2500 ppm. The compositions of LSW at 3500 and 4500 ppm have the same height of foam column, which is lower than the previous compositions. The lowest foam height is by the 6500 ppm LSW composition. After 40 minutes, we observe that the foam columns are still reducing. Here, the composition at 500 ppm still exhibits the highest foam column followed by that at 1000 ppm, then 2500 ppm, 3500 ppm, 6500 ppm and finally 4500 ppm with the lowest foam column. This same trend is observed after 2 hours. It is also important to note the very fast decrease of foam column for the composition at 4500 ppm. At the end of 6 and 12 hours, all the foam columns have reduced to zero, that is, no foam columns are observed. Figure 4. changes of foam column with time for the NaCl+1% AOS solution. Figure 5. changes of foam column with time for the KCl+1.5% AOS solution. Vol 9 (35) September Indian Journal of Science and Technology 9

10 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water 3.4 FST without Crude Oil (Mix+1%wt AOS) The mix composition shows a slightly different trend from those described above. From Figure 6, we still notice that the foam columns are decreasing throughout the time interval of 12 hours. In the beginning, the highest foam column is that of the 500 ppm composition followed by the 3500 ppm, then 2500 ppm, 4500 ppm, 1000 ppm, and finally the 6500 ppm composition. The compositions at 500 ppm and 3500 ppm maintain the same position of the first and second highest foam column for the first 6 hours. Thus, discussion is centered on the remaining concentrations. After 40 minutes (0.66 hours), the same trend is maintained except that the foam column of the composition at 1000 ppm now is higher than that of the 4500 ppm. For the next 2 hours, the foam column of the composition at 6500 ppm outweighs those at 1000 ppm and 4500 ppm. At the end of 4 hours, the 6500 ppm composition has the third highest foam column followed by the 2500 ppm, then 4500 ppm, and finally the 1000 ppm composition. At the end of 6 hours, the composition at 2500 ppm has the third highest foam column followed by the 1000 and 6500 ppm compositions that have the same column height and finally the 4500 ppm with the lowest foam column. At the end of 12 hours, the foam columns of all the compositions reduce to zero. 3.5 FST without Crude Oil (CaCl2, MgCl2, FW +1%wt AOS) Figure 7 shows the changes of foam column with time for the CaCl 2, MgCl 2, and FW+1%wt AOS compositions. Figure 6. changes of foam column with time for the Mix+1% AOS solution. Figure 7. changes of foam column with time for the CaCl2, MgCl2, and FW+1.5% AOS compositions. As shown, the FST for these compositions does not cover the whole range of concentrations. This is because of the AST screening phase whereby the missing concentrations were considered ineffective for further observation. For CaCl 2, in the beginning, the 500 ppm composition has a higher foam column than that at 1000 ppm. However, for the first 40 minutes (0.66 hours) the foam column of the 1000 ppm outweighs that of 500 ppm. Nonetheless, at the end of 2 hours, the 500 ppm composition overtakes the 1000 ppm composition and remains with a higher foam column until the end of 6 hours. Both foam columns reduce to zero at the end of 12 hours. The MgCl 2 composition exhibits exactly the same behavior as that of the CaCl 2 for the 500 and 1000 ppm compositions. In the first 2 hours, the foam column at 500 ppm and 1000 ppm are interchangeably overtaking each other. At the end of 4 and 6 hours the foam column of the 500 ppm composition dominates. Finally, both foam columns decrease to zero at the end of 12 hours. On the other hand, the foam column of the 2500 ppm remains the lowest for the first 6 hours and becomes zero at the end of the 12 hours. The foam column for the formation water is decreasing for the first 2 hours and becomes zero at the end of 4 hours. 3.6 FST with Crude Oil A (NaCl + 1%wt AOS) In the presence of crude oil A, the foam columns are still decreasing with time. Figure 8 represents the changes of foam column of the NaCl composition in the presence of crude oil A. As shown, the composition at 500 ppm has the highest foam column, while that at 6500 ppm has the lowest foam column for the first 2 hours. At the end of 10 Vol 9 (35) September Indian Journal of Science and Technology

11 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour tion. Foam columns continue to decrease up to 2 hours where the 500 ppm composition still presents the highest foam column followed by the 1000 ppm composition. However, the rest of the compositions foam columns have decreased to zero. Finally, at the end of 3 and 4 hours all the foam columns have reduced to zero. Figure 8. changes of foam column with time for the NaCl+1% with crude oil A. 3 and 4 hours, the foam columns of all the compositions reduce to zero. The trend for the remainder of the compositions is as follows. In the beginning, the 1000 ppm composition presents the highest foam column followed by 3500 ppm, then 2500 ppm and finally the 4500 ppm composition. However, for the first 2 hours, the composition at 3500 ppm is what presents the highest foam column followed by the 2500 ppm, then 1000 ppm and finally the 4500 ppm. At the end of the first hour, the compositions at 1000 ppm and 3500 ppm present the same foam columns that are higher than that of the 2500 ppm composition. Here, we also observe that the foam column of the compositions at 4500 and 6500 ppm have decreased to zero. At the end of 2 hours, only the foam columns of the 500 ppm and 1000 ppm have remained and the rest has reduced to zero. 3.7 FST with Crude Oil A (KCl + 1%wt AOS) Figure 9 shows the changes of foam column with time for the NaCl+1% composition in the presence of crude oil A. In the beginning, the highest foam column is that of the 500-ppm composition. This is followed by the 2500-ppm composition then 1000 ppm, 3500 ppm, 4500 ppm and finally the 6500-ppm composition. In the first 0.5 hours, however, the highest foam column is that of the 1000 ppm followed by 500 ppm, then 2500 ppm, 3500 ppm, 4500 ppm and finally the 6500 ppm. At the end of the first hour, the 500 ppm overtakes the 1000-ppm composition by having the highest foam column again. This I followed by the 1000 ppm composition, then 2500 ppm, 3500 ppm, 4500 ppm and finally the 6500 ppm composi- 3.8 FST with Crude Oil A (Mix + 1%wt AOS) Here, still the foam columns for all the compositions are decreasing with time and at the end of 3 and 4 hours all the columns reduce to zero as shown in Figure 10. In the beginning, the 500 ppm composition has the highest foam column followed by the 3500 composition, then the 2500, 1000, 6500, and 4500 ppm compositions. The same trend is observed for the first 0.5 hours. However, slight changes are noticed at the end of the first hour. Figure 9. changes of foam column with time for the KCl+1% with crude oil A. Figure 10. changes of foam column with time for the Mix+1% with crude oil A. Vol 9 (35) September Indian Journal of Science and Technology 11

12 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water Here, the foam column of the 1000 ppm composition becomes greater than that of the 2500 ppm composition. At the end of 2 hours, the still the 500 ppm composition presents the highest foam column followed by the 3500 ppm composition, then 2500 ppm and finally the 1000 ppm composition. The foam columns of the remaining compositions have decreased to zero. 3.9 FST with Crude Oil A (CaCl2, MgCl2, FW +1%wt AOS) Figure 11 shows the changes of foam columns for the CaCl 2, MgCl 2, FW+1%wt AOS in the presence of crude oil A. From the figure, we observe that there is a dramatic decrease of foam columns from one time interval to another. In addition, the foam columns decrease to zero right in the first hour. Nonetheless, it is still important to observe the trends. The CaCl 2 composition is presented at two concentrations, 500 ppm and 100 ppm. For the first 0.5 hours, the 500-ppm composition has a higher foam column as compared to the 1000 ppm composition. At the end of 1, 2,3, and 4 hours, the foam columns reduce to zero. On the other hand, the MgCl 2 composition is presented at three concentrations, i.e., at 500, 1000, and 2500 ppm. In the beginning, the 500 ppm composition has the highest foam column followed by the 1000 ppm and finally the 2500 ppm. This trend is also observed after one hour. For the remaining hours, all the foam columns decrease to zero. The foam column of the formation water reduces completely to zero right in the first 0.5 hours and remains zero until the end of the 4 hours FST with Crude Oil B (NaCl + 1%wt AOS) Similar to the case of crude oil A, the foam columns of the compositions with crude oil B are decreasing with time. Figure 12, represents the changes of the foam columns with time for the NaCl +1%wt AOS composition in the presence of Crude Oil B. As it can be seen, the changes of foam column are consistent. In the beginning, the 500 ppm composition has the highest foam column. This is followed by the 1000 ppm composition, then the 2500, 3500, 4500, and 6500 ppm compositions. The same trend is observed in the second and third hour. However, the foam columns of the 4500 and 6500-ppm compositions reduce to zero in the second hour and third hour. In addition, the foam columns of the 2500 and 3500 ppm decrease to zero in the third hour. The foam columns of all the compositions reduce to zero in the last 4 hours FST with Crude Oil B (KCl + 1%wt AOS) Here we also observe a consistent trend. The decrease in foam columns maintains the same ranks. As shown in the Figure 13 in the beginning the highest foam column is that of the 500-ppm composition which is followed by 1000, 2500, 3500, and 4500 and finally 6500 ppm composition. This same rank continues up to the second hour where the foam column of the 6500 ppm reduces to zero. In the third hour, the foam columns of the 3500, 4500, and 6500 compositions reduce to zero. Finally, at the end of the 4 hours, all the foam columns decrease to zero. Figure 11. changes of foam column with time for the CaCl 2, MgCl 2, FW+1% AOS with crude oil A. Figure 12. changes of foam column with time for the NaCl+1% with crude oil B. 12 Vol 9 (35) September Indian Journal of Science and Technology

13 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour 3.12 FST with Crude Oil B (Mix + 1%wt AOS) Figure 14 shows the change of foam column with time for the Mix +1.5% AOS compositions in the presence of crude oil B. In the beginning, the highest foam column is that of the 500-ppm composition. This is followed by the 3500-ppm composition then the 2500, 1000, 6500 and 4500-ppm compositions. The same trend is observed for the first 0.5 hours. At the end of the first hour, there is a slight change. Here, the foam column of the 4500-ppm composition outweighs that of the 6500 ppm. At the end of the second hour, the trend is similar to that observed in the beginning. In addition, the foam column of the 4500 ppm composition has reduced to zero. At the end of the third hour, the still the 500 ppm composition has the highest foam column followed by the 3500 ppm composition, then the 2500, 1000, and finally the 4500 and Figure 13. changes of foam column with time for the KCl+1% with crude oil B ppm that have both reduced to zero. The foam columns of all the compositions reduce to zero at the end of the fourth hour FST with Crude Oil B (CaCl2, MgCl2, FW +1%wt AOS) Figure 15 shows the change of foam columns for the CaCl 2, MgCl 2, and FW for 1%wt concentration of AOS in the presence of crude oil B. The foam columns are decreasing until becoming zero at the end the second hour continuing until the fourth hour. For CaCl 2, in the first 0, 0.5, and 1 hours the 500 ppm composition has a higher foam column as compared the 1000 ppm composition. The foam columns for both compositions reduce to zero at the end of the second hour and continuing until the fourth hour. Similarly, for MgCl 2 in the beginning the 500-ppm composition has the highest foam column followed by the 1000-ppm composition and that of 2500 ppm having the lowest column. The same trend is observed until the end of the first hour. Starting from the second hour up to the fourth, all the foam columns decrease to zero. The foam column for the formation water decreases continuously until becoming zero in the first hour. It remains zero until the end of the fourth hour. Analogous to the results of crude oil A, here we also obtain the most stable foam column for the SAS compositions at 500 ppm. Therefore, the same compositions are considered for further observation in the next step of IFT test. In the absence of oil, the stability of the generated foam depends greatly on the concentration and composition of the LSW in the SAS. From the results, it was observed that the foam stability is inversely propor- Figure 14. changes of foam column with time for the Mix+1% with crude oil B. Figure 15. Changes of foam column with time (CaCl 2, MgCl 2, and FW +1%wt AOS) oil B. Vol 9 (35) September Indian Journal of Science and Technology 13

14 Investigation into the Effects of Crude Oil on Foam Stability by using Different Low Salinity Water tional to the concentration of the LSW. The lesser is the concentration of the LSW, the more stable is the foam column. The most stable foam column was found to be at 500 ppm. As for composition, the foam column was more stable for the monovalent cations of Na + and K + as compared to the divalent cations of Ca 2+ and Mg 2+, and mix composition. The foam is critically unstable in the presence of formation water. The results of FST in the absence of crude oil are similar to those in the presence of crude oil except that the stability of the foam is not maintained for long times; instead, it decreases rapidly. The foam columns in the presence of crude oil B (with higher TBN and lower TAN) were more stable than those in the presence of crude oil A (with higher TAN and lower TBN). This is obviously an evidence for the dependence of foam strength on the crude oil TAN and TBN. Thus, we may imply that foam generation will be more favored when the crude oil has high TBN and low TAN. Overall, from the results we observe that for all the SAS compositions, the most stable foam column is obtained at 500 ppm of LSW. Therefore, we choose the compositions at 500 ppm for performing the proceeding IFT test Interfacial Tension (IFT) IFT test was performed with the objective of finding the minimum Interfacial Tension. It was measured by the spinning drop method for both crude oils A and B. Table 9 and its corresponding plot on Fig. 17 show the results obtained from the test. Considering only for the IFT values with crude oil A, the lowest IFT value is that of the Mix+1%wt AOS composition followed by the KCl+1wt%AOS, NaCl+1wt%AOS, CaCl 2 +1wt%AOS and finally the MgCl 2 +1wt%AOS composition, all at 500ppm. Similarly, for crude oil B at 500ppm, still the Mix+1%wt AOS composition has the lowest IFT followed by the KCl+1wt%AOS, then NaCl+1wt%AOS, CaCl 2 +1wt%AOS and finally the MgCl 2 +1wt%AOS composition. From the figure 16, it is obvious that for all the compositions, the IFT values obtained with crude oil B are lower than those obtained with crude oil A. The pendant drop method for IFT measurement requires the mixture of all the fluids taken into consideration. For this case, the mixture was performed by adding SAS (LSW+ surfactant) and oil. Usually, this mixture results in a clear, stable and isotropic solution called Microemulsion. A proper characterization of the phase behavior of the micro-emulsions and crude oil composition is Table 7. IFT values for each Surfactant aqueous solution with crude oil A and B Component Name important for explaining the decrease or increase of IFT. The increase of the salinity of the brine component in the micro-emulsion solution causes a decrease in the solubility of the ionic surfactant 11. Moreover, the increase of organic acids in crude oil, i.e., higher total acid number and lower base number, causes a decrease of the surfactant-oil solubility and thus an increase in IFT. This is because of the high specific gravity of the organic acids 12. On the other hand, crude oil with low total acid number and high total base number increases the surfactant-oil solubility, and thus a decrease in IFT. 4. Conclusions IFT [mn/m] for Crude Oil A IFT [mn/m] for Crude Oil B NaCl-500ppm+1% wt AOS KCl-500ppm+1% wt AOS CaCl 2-500ppm+1%wt AOS MgCl2-500ppm+1%wt AOS Mix-500ppm+1%wt AOS FW ppm+1%wt AOS Figure 16. Plot of IFT values for both crude oil A and B. The stability of the SAS for the KCl and NaCl compositions remains stable for the given AOS and LSW concentrations. However, for the SAS of the CaCl 2, MgCl 2, and Mix compositions, the stability is considerably affected by the concentration of both the LSW and surfactant. As the LSW concentration increases, the more likely is the tendency of the solution to precipitate or become cloudy, and vice-versa. Furthermore, for the AOS composition, 14 Vol 9 (35) September Indian Journal of Science and Technology

15 Abdolmohsen Shabib-Asl, Mohammed Abdalla Ayoub, Khaled Abdalla Elraies, Seyednooroldin Hosseini and Hamed Hematpour the best concentration is at 1% AOS. In the absence of oil, the strength of foam is highly dependent on the concentration and composition of the LSW in the SAS. The foam decays rapidly at higher LSW concentration. The foam columns in the presence of crude oil B (with higher TBN and lower TAN) were more stable than those in the presence of crude oil A (with higher TAN and lower TBN). This is obviously an evidence for the dependence of foam strength on the crude oil TAN and TBN. Thus, we may conclude that foam generation and stability will be more favored when the crude oil has high TBN and low TAN. The Surfactant Aqueous Solution composed of mix composition significantly reduced the IFT in the presence of both crude oils A and B. Lower IFT values were similarly obtained by the KCl and NaCl composition for both crude oils. However, the reduction of IFT was more pronounced for crude oil B rather than crude oil A. Therefore, at higher values of TBN and low TAN, the IFT will significantly decrease as compared to the case of higher TAN and lower TBN. Overall, the paper presents a detailed and stepwise chemical screening process that could significantly add valuable knowledge to the existing body of literature. Therefore, it is highly recommended for future reference. 5. Acknowledgment The authors would like to acknowledge the supports received from Universiti Teknologi PETRONAS, especially for assuring the URIF grant for the successful completion of the research. 6. References 1. Shabib-Asl A, Ayoub MA, Alta ee AF, Bin Mohd Saaid I, Paulo Jose Valentim P. Comprehensive Review of Foam Application during Foam Assisted Water Alternating Gas (FAWAG) Method. Research Journal of Applied Sciences, Engineering and Technology. 2014; 8(17): Prince MJA. optimizing ultralow interfacial tension by altering surfactant concentration through emulsion test. Indian Journal of Science and Technology Nov; 7(S7). Doi: /ijst/2014/v7iS7/ Prince MJA. Experimental study on nonionic surfactants for minimizing surface adsorption as an Improved Oil Recovery (IOR) process. Indian Journal of Science and Technology Oct; 7(S6). Doi: /ijst/2014/ v7is6/ Julius P, Ananthanarayanan PN, Anbazhagan G. Analysis on capillary pressure curves by wettability modification through surfactants. Indian Journal of Science and Technology Jul; 8(14). Doi: /ijst/2015/ v8i14/ Julius P, Ananthanarayanan PN, Srinivasan V. Investigation of Enhanced Oil Recovery (EOR) Surfactants on Clay Mixed Sandstone Reservoirs for Adsorption. Indian Journal of Science and Technology Jul. 8(14). Doi: / ijst/2015/v8i14/ Bansal VK, Shah DO. The Effect of Divalent Cations (Ca 2+ and Mg 2+ ) on the Optimal Salinity and Salt Tolerance of Petroleum Sulfonate and Ethoxylated Sulfonate Mixtures in Relation to Improved Oil Recovery. J Am Oil Chem Soc. 1978; 55(3): Schramm LL, Wassmuth F. Foams: Fundamentals and Application in the Petroleum Industry, Washington, DC, USA: American Chemical Society Green DW, Willhite GP. Enhanced Oil Recovery. SPE Text Book Series. 1998; Shabib-Asl A, Mohammed MAA, Kermanioryani M, Valentim PPJ. Effects of Low Salinity Water Ion Composition on Wettability Alteration in Sandstone Reservoir Rock: A Laboratory Investigation. Journal of Natural Sciences and Research. 2014; 4: Shabib-Asl A, Ayoub MA, Bin Mohd Saaid I, Paulo Jose Valentim P. Experimental investigation into effects of crude oil acid and base number on wettability alteration by using different low salinity water in sandstone rock. Journal of the Japan Petroleum Institute. 2015; 58(4):228 36, 11. Llama O. G: Mobility Control of Chemical EOR Fluids Using Foam in Highly Fractured Reservoirs. MS Thesis, The University of Texas at Austin May. 12. Mwangi P. An Experimental Study of Surfactant Enhanced Water Flooding. MS Thesis, Louisiana State University Dec. Vol 9 (35) September Indian Journal of Science and Technology 15