scholarly journals Bulk rheology characterization of biopolymer solutions and discussions of their potential for enhanced oil recovery applications

2021 ◽  
Vol 11 (1) ◽  
pp. 123-135
Author(s):  
Karl Jan Clinckspoor ◽  
Vitor Hugo de Sousa Ferreira ◽  
Rosangela Barros Zanoni Lopes Moreno

Enhanced oil recovery (EOR) techniques are essential to improve oil production, and polymer flooding has become one of the promising technologies for the Brazilian Pre-Salt scenario. Biopolymers offer a range of advantages considering the Pre-Salt conditions compared to synthetic polymers, such as resistance to high salinity, high temperature, and mechanical degradation. In that sense, bulk rheology is the first step in a workflow for performance analysis. This paper presents a rheological analysis of four biopolymers (Schizophyllan, Scleroglucan, Guar Gum, and Xanthan Gum) in concentrations from 10 to 2,300 ppm, generally suitable for EOR applications, in temperature levels of 25, 40, 50, 60 and 70°C and two brines of 30,100 ppm and 69,100 ppm total dissolved solids, which aim to model seawater and the mixture between injected seawater and reservoir water typical in Pre-Salt conditions. The pseudoplastic behavior, the overlap concentration, and the activation energy were determined for each polymer solution. The structural differences in the polymers resulted in different rheological behaviors. Schizophyllan is the most promising, as its viscosifying power is higher than synthetic polymers comparable to Xanthan Gum.  Its resistance at high temperatures is higher than that of synthetic polymers. Scleroglucan behaved similarly to Xanthan Gum, with the added advantage of being nonionic. Guar Gum had the lowest viscosities, highest overlap concentrations, and most pronounced viscosity decay among the tested polymers. To the author’s knowledge, rheological studies of the biopolymers presented here, considering the viscosities and the overlap concentration and activation energy, in the Pre-salt conditions, are not available in the literature and this will benefit future works that depend on this information

Author(s):  
K. Pallavi ◽  
T. Pallavi

Objective: The main aim of the present research was to develop an oral fast dissolving polymeric film (FDF) with good mechanical properties, faster disintegration and dissolution when placed on the tongue.Methods: Eletriptan hydrobromide is prescribed for the treatment of mild to a moderate migraine. The polymers selected for preparing films were Pullulan, Maltodextrin (MDX), Acacia, Sodium alginate (SA), Locust bean gum (LBG), Guar gum (GG), Xanthan gum (XG), Polyvinyl alcohol (PVA), Polyvinyl pyrrolidine (PVP), Hydroxyl propyl methyl cellulose (HPMC) E5, and HPMC E15. Twelve sets of films FN1–FN12 were prepared by solvent casting method with Pullulan and combination of Acacia, MDX, SA, LBG, GG, XG, PVA, PVP, HPMC E5 and HPMC E15. Five sets of films FS1–FS5 were prepared using synthetic polymers like PVA, PVP, HPMC E5 and HPMC E15.Results: From all the prepared polymer formulations, FN2, FN8, and FS3 were selected based on disintegration time, and drug release and amongst this three FN2 was optimised based on its disintegration time (D. T). The percent drug release of the optimised film was compared with the percent release of the pure drug.Conclusion: The optimised formulation had a D. T of 16 s and a percent drug release of 97.5% in 10 min in pH 6.8 phosphate buffer and 100.6% drug release in 10 min in 0.1N HCl.


2020 ◽  
Vol 10 (8) ◽  
pp. 3947-3959
Author(s):  
Kyle Medica ◽  
Rean Maharaj ◽  
David Alexander ◽  
Mohammad Soroush

Abstract Trinidad and Tobago (TT) is seeking to develop more economical methods of enhanced oil recovery to arrest the decline in crude oil production and to meet the current and future energy demand. The utilization of alkaline-polymer flooding to enhance oil recovery in TT requires key studies to be conducted to obtain critical information of the flooding system (soil type, additive type, pH, adsorption characteristics and rheological (flow) characteristics). Understanding the role of, interplay and optimizing of these variables will provide key input data for the required simulations to produce near realistic projections of the required EOR efficiencies. The parameters of various wells in TT were compared to the screening criteria for alkali-polymer flooding, and the EOR 4 well was found to be suitable and thus selected for evaluation. Laboratory adsorption studies showed that the 1000 ppm xanthan gum flooding solution containing 0.25% NaOH exhibited the lowest absorption capacity for the gravel packed sand and exhibited the lowest viscosity at all the tested shear rates. The lowest adsorption was 2.27 × 10−7 lbmole/ft3 which occurred with the 1000 ppm xanthan gum polymer containing 0.25% NaOH, and the evidence showed that the polymer was adsorbed on the other side of the faults, indicating that it has moved further and closer to the producing well. Implementation of an alkali polymer flooding resulted in an incremental increase in the recovery factors (~ 3%) compared to polymer flooding; however, a change in the oil recovery as a function of the alkaline concentration was not observed. The simulated economic analysis clearly shows that all the analysed EOR scenarios resulted in economically feasible outcomes of net present value (NPV), Internal Rate of Return (IRR) and payback period for oil price variations between $35 and $60 USD per barrel of oil. A comparison of the individual strategies shows that the alkali-polymer flood system utilizing 0.25% sodium hydroxide with 1000 ppm xanthan gum is the best option in terms of cumulative production, recovery factor, NPV, IRR and time to payback.


2020 ◽  
Vol 10 (2) ◽  
pp. 131-141
Author(s):  
Gustavo Maya Toro ◽  
Julia Jineth Herrera Quintero ◽  
Ruben Hernan Castro Garcia ◽  
Henderson Ivan Quintero Pérez ◽  
Dalje Sunith Barbosa Trillos ◽  
...  

With the design of experiments (DoE), this study analyses the influence of physical (capillary diameter and pressure drop) and chemical variables (salinity, polymer concentration, and molecular weight) on the mechanical degradation of partially hydrolyzed polyacrylamide-type polymer solutions (HPAM) used in enhanced oil recovery processes. Initially, with the help of a fractional factorial design (2k-p), the variables with the most significant influence on the polymer's mechanical degradation were found. The experimental results of the screening demonstrate that the factors that statistically influence the mechanical degradation are the molecular weight, the diameter of the capillary, and the pressure differential. Subsequently, a regression model was developed to estimate the degradation percentages of HPAM polymer solutions as a function of the significant factors influencing the mechanical degradation of polymer solutions. This model had a 97.85% fit for the predicted values under the experimental conditions. Likewise, through the optimization developed by the Box Behnken response surface methodology, it was determined that the pressure differential was the most influential factor. This variable was followed by the capillary diameter, where less than 50% degradation rates are obtained with low polymer molecular weight (6.5 MDa), pressure differentials less than 500 psi, and diameters of the capillary greater than 0.125 inches.


2021 ◽  
Vol 11 (4) ◽  
pp. 1905-1913
Author(s):  
Tagwa A. Musa ◽  
Ahmed F. Ibrahim ◽  
Hisham A. Nasr-El-Din ◽  
Anas. M. Hassan

AbstractChemical enhanced oil recovery (EOR) processes are usually used as additives for hydrocarbon production due to its simplicity and relatively reasonable additional production costs. Polymer flooding uses polymer solutions to increase oil recovery by decreasing the water/oil mobility ratio by increasing the viscosity of the displacing water. The commonly used synthetic water-soluble polymer in EOR application is partially hydrolyzed polyacrylamide (HPAM). However, synthetic polymers in general are not attractive because of high cost, environmental concerns, limitation in high temperature, and high-salinity environment. Guar gum is an environmentally friendly natural water-soluble polymer available in large quantities in many countries and widely used in various applications in the oil and gas industry especially in drilling fluids and hydraulic fracturing operations; however, very limited studies investigated on guar as a polymer for EOR and no any study investigated on its uses in high-temperature and high -salinity reservoirs. The objective of this study is to confirm the use of guar gum as a natural polymer for EOR applications in sandstone reservoirs and investigate its applicability for high-temperature and high-salinity reservoirs. The study experimentally investigated rheological characteristics of a natural polymer obtained from guar gum with consideration of high temperature (up to 210 °F) and high salinity (up to 20% NaCl) and tested the guar solution as EOR polymer. The results of this study show that the guar solution can be used as an environmentally friendly polymer to enhance oil recovery. Based on the results, it can be concluded that guar gum shows shear-thinning behavior and strongly susceptible to microbial degradation but also shows a very good properties stability in high temperature and salinity, where in low shear rate case, about 100 cp viscosity can be achieved at 210 °F for polymer prepared in deionized water. Guar polymer shows good viscosity in the presence of 20% NaCl where the viscosity is acceptable for temperature less than 190 °F. Also, the flooding experiment shows that the recovery factor can be increased by 16%.


ACS Omega ◽  
2021 ◽  
Vol 6 (36) ◽  
pp. 23421-23431
Author(s):  
Shimaa. M. Elsaeed ◽  
Elsayed Gamal Zaki ◽  
Walaa A. E. Omar ◽  
Ahmed Ashraf Soliman ◽  
Attia Mahmoud Attia

2020 ◽  
Vol 10 (8) ◽  
pp. 3779-3789 ◽  
Author(s):  
Tina Coolman ◽  
David Alexander ◽  
Rean Maharaj ◽  
Mohammad Soroush

Abstract The economy of Trinidad and Tobago which mainly relies on its energy sector is facing significant challenges due to declining crude oil production in a low commodity price environment. The need for enhanced oil recovery (EOR) methods to meet the current and future energy demands is urgent. Studies on the use of polymer flooding in Trinidad and Tobago are limited, especially in terms of necessary data concerning the characterization of the adsorption of polymer flooding chemicals such as xanthan gum and aquagel polymers on different soil types in Trinidad and the viscosity characteristics of the polymer flooding solutions which affect the key attributes of displacement and sweep efficiency that are needed to predict recovery efficiency and the potential use of these flooding agents in a particular well. Adsorption and viscosity experiments were conducted using xanthan gum and aquagel on three different soil types, namely sand, Valencia clay (high iron) and Longdenville clay (low iron). Xanthan gum exhibited the lowest adsorption capacity for Valencia clay but absorbed most on sand at concentrations above 1000 ppm and Longdenville clay below 1000 ppm. At concentrations below 250 ppm, all three soil-type absorbent materials exhibited similar adsorption capacities. Aquagel was more significantly absorbed on the three soil types compared to xanthan gum. The lowest adsorption capacity was observed for Valencia clay at concentration levels above 500 ppm; however, the clay had the highest adsorption capacity below this level. Sand had the highest adsorption capacity for aquagel at concentrations above 500 ppm while Longdenville clay was the lowest absorbent above 500 ppm. Generally, all three soil types had a similar adsorption capacity for xanthan gum at a concentration level of 250 ppm and for aquagel at a concentration level of 500 ppm. The results offered conclusive evidence demonstrating the importance that the pore structure characteristics of soil that may be present in oil wells on its adsorption characteristics and efficiency. Xanthan gum polymer concentration of 2000 ppm, 1000 ppm and 250 ppm showed viscosities of 125 cp, 63 cp and 42 cp, respectively. Aquagel polymer concentrations of 2000 ppm, 1000 ppm and 250 ppm showed viscosities of 63 cp, 42 cp and 21 cp, respectively. Aquagel polymer solutions were found to generally have lower viscosities than the xanthan gum polymer solutions at the same concentration. Adsorption and viscosity data for the xanthan gum and aquagel polymers were incorporated within CMG numerical simulation models to determine the technical feasibility of implementing a polymer flood in the selected EOR 44 located in the Oropouche field in the southwest peninsula of the island of Trinidad. Overall, aquagel polymer flood resulted in a higher oil recovery of 0.06 STB compared to the xanthan gum polymer flood, so the better EOR method would be aquagel polymer flood. Additionally, both cases of polymer flooding resulted in higher levels of oil recovery compared to CO2 injection and waterflooding and therefore polymer flooding will have greater impact on the EOR 44 well oil recovery.


1981 ◽  
Vol 21 (02) ◽  
pp. 205-217 ◽  
Author(s):  
Charles J. Norton ◽  
David O. Falk ◽  
Wayne E. Luetzelschwab

Abstract Using standard microbiological techniques in a semipilot plant-scalable fermenter, xanthan-specific culture techniques developed by the U.S. Dept of Agriculture's Northern Regional Research Laboratory (NRRL) were used at Marathon Oil Co.'s Denver Research Center (DRC) to obtain improved and reproducible high conversions and yields of xanthan biopolymer broth. Practical nutrients and fermenter parameters were studied to define and improve the viscosity performance and economics of xanthan broth production for thickening water in the Maraflood(TM) enhanced oil recovery process. Introduction Xanthan gum biopolymer shows promise for enhanced oil recovery. One of its current major uses is in drilling muds. After a preliminary review of its characteristics and potential for manufacture by fermentation, a scalable laboratory pilot study was conducted at DRC to evaluate the suitability of several feedstocks and bacterial organisms.Our fermentation results confirm NRRL procedures and recommendations for this bacterial fermentation and indicate a number of practical feedstocks for producing high-viscosity broths. We can reproduce xanthan broths as viscous as those previously furnished to us by NRRL and various commercial suppliers interested in this potential market for enhanced oil recovery. Initial economic estimates indicate that xanthan broths can be made for about one-half the price of commercially available biopolymer.Our research to date on the biopolymer xanthan gum and fermentation broth is summarized. This includes the chemical and physical properties, synergistic interactions, salinity effects, physical and chemical modifications, chemical and biological stabilities, mobility control properties, and oil recovery performances in cores. Experimental results indicate that broad ranges of readily available carbohydrate and nitrogen sources are suitable and economical alternative substrates for this fermentation. Dissolved oxygen concentration and oxygen usage are practical parameters for monitoring the fermentation. Experimental Carbon and nitrogen sources from several commercial suppliers were screened. Staleydex(TM) 333 dextrose (a carbon source) and Brown-Forman corndistillers dried solubles (DDS) (a nitrogen source) were selected for reproducibility studies. Enzose E-084 cornstarch hydrolysate and Argo(TM) corn steep were furnished by Corn Products Corp.Several recommended strains of Xanthomonas campestris were obtained from the American Type Culture Bank and the NRRL in Peoria, IL. The strain selected for most of our investigation was NRRL B-1459-4L. A sample of Xanthomonas manihotis from the American Type Culture Bank also was evaluated. Apparatus A Psycrotherm controlled environmental incubator shaker was used to culture cells on plates and in liquid inocula. A 14-L Microferm(TM) fermenter obtained from the New Brunswick Scientific Co. (Fig. 1) had stirring, aeration, temperature control, pressure control, foam control, and pH control. SPEJ P. 205^


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