A Novel Thermoviscosifying Water-Soluble Polymer for Enhancing Oil Recovery from High-Temperature and High-Salinity Oil Reservoirs

2011 ◽  
Vol 306-307 ◽  
pp. 654-657 ◽  
Author(s):  
Yu Wang ◽  
Zhi Yong Lu ◽  
Yu Gui Han ◽  
Yu Jun Feng ◽  
Chong Li Tang

Polymer flooding represents one of the most efficient processes to enhance oil recovery, but the poor thermostability and salt tolerance of the currently-used partially hydrolyzed polyacrylamide (HPAM) impeded its use in high-temperature and high-salinity oil reservoirs. “Smart” thermoviscosifying polymers (TVPs) may overcome the deficiencies of HPAM. Steady and dynamic rheological behaviors against temperature of a novel TVP were examined in this work in comparison with a commercial HPAM polymer. It was found when increasing temperature, both apparent viscosity and elastic modulus increase for TVP aqueous solution, but decrease for HPAM solution. The results indicate that TVP shows some potential to be used in enhancing oil recovery from high-temperature and high-salinity oil reservoirs.

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Huang Zhiyu ◽  
Lu Hongsheng ◽  
Zhang Tailiang

Abstract In order to enhance oil recovery in high-temperature and high-salinity oil reservoirs, the copolymeric microspheres containing acrylamide (AM), acrylonitrile (AN) and AMPS was synthesized by inverse suspension polymerization. The copolymeric microsphere was very uniform and the size could be changed according to the condition of polymerization. The lab-scale studies showed that the copolymeric microsphere exhibit good salt-tolerance and thermal-stability when immersed in 20×105 mg/L NaCl(or KCl) solution, 7500 mg/L CaCl2 (or MgCl2) solution or 2000 mg/L FeCl3 solution, respectively. The copolymeric microsphere showed satisfactory absorbency rates. The sand-pipes experiments confirmed that the average toughness index was 1.059. It could enhance the oil recovery by about 3% compared with the corresponding irregular copolymeric particle.


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%.


2018 ◽  
Vol 15 (30) ◽  
pp. 380-386
Author(s):  
Y. V. SAVINYKH ◽  
L. D. LANG

Polymer flooding is technologically simple and highly effective method of enhanced oil recovery. The method is based on adding a small amount of polymer in conventional water flooding of oil reservoirs. The increase in viscosity and the reduction of the mobility of injected water are to equalize the displacement front by slowing the moving of water in the highly permeable zones and restricting the formation of water finger. These factors help to increase the sweep efficiency and oil-water displacement efficiency during flooding. Polymer flooding has been used successfully in clastic and carbonate reservoirs, as well as in low-permeability reservoirs such as a fractured basement. However, most of the current polymer gel used for control water flows are decayed by a high content of ions Ca2+ and Mg2+ in formation water or in injected water. Similarly, polymer gels lose their stability at high reservoir temperature (above 70°C). Developing water-soluble polymer, which does not change their rheological properties under high salinity and high temperature (over 100°C), is very important when producing offshore, where sea water is commonly used for flooding (high salinity of 30-40 g/L).


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7468
Author(s):  
Xiaoqin Zhang ◽  
Bo Li ◽  
Feng Pan ◽  
Xin Su ◽  
Yujun Feng

Water-soluble polymers, mainly partially hydrolyzed polyacrylamide (HPAM), have been used in the enhanced oil recovery (EOR) process. However, the poor salt tolerance, weak thermal stability and unsatisfactory injectivity impede its use in low-permeability hostile oil reservoirs. Here, we examined the adaptivity of a thermoviscosifying polymer (TVP) in comparison with HPAM for chemical EOR under simulated conditions (45 °C, 4500 mg/L salinity containing 65 mg/L Ca2+ and Mg2+) of low-permeability oil reservoirs in Daqing Oilfield. The results show that the viscosity of the 0.1% TVP solution can reach 48 mPa·s, six times that of HPAM. After 90 days of thermal aging at 45 °C, the TVP solution had 71% viscosity retention, 18% higher than that of the HPAM solution. While both polymer solutions could smoothly propagate in porous media, with permeability of around 100 milliDarcy, TVP exhibited stronger mobility reduction and permeability reduction than HPAM. After 0.7 pore volume of 0.1% polymer solution was injected, TVP achieved an incremental oil recovery factor of 13.64% after water flooding, 3.54% higher than that of HPAM under identical conditions. All these results demonstrate that TVP has great potential to be used in low-permeability oil reservoirs for chemical EOR.


2021 ◽  
Vol 874 ◽  
pp. 45-49
Author(s):  
Ihsan Arifin ◽  
Grandprix Thomryes Marth Kadja ◽  
Cynthia L. Radiman

Enhanced Oil Recovery (EOR) is a promising technology for increasing crude oil production, especially from old wells. Polymer flooding is one of the techniques used in EOR in which the water-soluble polymer is added to increase the viscosity of the injected fluid. However, this technique has not been implemented in Indonesia due to the unavailability of locally-synthesized polymers. Therefore, this research aims to synthesize polyacrylamides and their partially-hydrolyzed derivatives and to study the possibility of their utilization for the EOR application. Various polymerization conditions using potassium persulfate (KPS) as initiators have been realized and the resulting polymers were characterized using FTIR spectroscopy and rheology measurement. It was found that higher monomer concentration resulted in higher viscosity-average molecular weight of polyacrylamide. Further study revealed that the hydrolysis of polyacrylamide by alkaline solution significantly increased the viscosity of 1000 ppm solution from 1.5 to 145.40 cP at room temperature, which is comparable to one of the commercial products. These results showed that the simple synthesis and hydrolysis method could be effectively used to produce water-soluble polymers for the EOR application.


2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Lei Zhang ◽  
Cheng Jing ◽  
Jing Liu ◽  
Khan Nasir

Due to the limited temperature resistance, the deep conformance control technology of using the conventional hydrolyzed polyacrylamide (HPAM) gel failed to enhance oil recovery in high-temperature heterogeneous oil reservoirs. Therefore, it is necessary to develop a gelant with high temperature resistance to meet the demands of increasing oil production and decreasing water cut in high-temperature heterogeneous oil reservoirs. In this paper, a copolymer is first synthesized by the method of inverse emulsion polymerization using 2-acrylamide-2-tetradecyl ethyl sulfonic acid (AMC16S), acrylamide (AM), and acrylic acid (AA). The developed copolymer has a highly branching skeleton and can resist temperature up to 100 °C. And then, a gelant with high temperature resistance and good shear resistance can be formed by mixing a certain proportion of the developed copolymer and polyethyleneimine (PEI). After the controllable gelation, a copolymer gel is formed and the formed gel can maintain the stable performance for a long time in the high-temperature environment. Experimental results show that the developed gelant can be applied in the conformance control of high-temperature heterogeneous oil reservoir.


2021 ◽  
Vol 8 ◽  
Author(s):  
Gang Lu ◽  
Jikuan Zhao ◽  
Shaoqi Li ◽  
Yuquan Chen ◽  
Chunfang Li ◽  
...  

Partially hydrolyzed polyacrylamide (HPAM) was widely implemented to improve the rheological properties of displacing fluids, but the high temperature and salinity of the reservoir brine limited their applications. Herein, copolymers including HPAM, zwitterion-modified HPAM (z-HPAM), PEG-modified HPAM (p-HPAM), and zwitterion/PEG-modified HPAM (zp-HPAM) were prepared by free radical polymerization in an aqueous solution. The viscosity of these copolymers under different temperature and salinity was measured in aqueous solution. It is found that the viscosity of the HPAM under the harsh condition (90oC, 20 × 104 mg/L salinity) is only 9.6% of that value under the normal condition (25oC, pure water), while the z-HPAM can significantly improve salt resistance by the effects of salting-in effect and intermolecular electrostatic crosslinking, showing a viscosity retention of 22.9% under the harsh condition. The addition of PEG-containing monomer can strengthen hydrogen bonding between the polymer chains and form a sterically ordered structure with improved salinity and temperature resistance. The synergistic effect of zwitterion units and PEG units endows the zp-HPAM with good salinity and temperature resistance; thus, the sample viscosity under the harsh condition remains 170 mPa s, which retains 29% of the value under the normal condition. The enhanced rheology properties of the zp-HPAM under the harsh condition are significant for the enhanced oil recovery of water-soluble polymer flooding.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Chengli Zhang ◽  
Peng Wang ◽  
Guoliang Song

Based on the properties of high temperature and salinity reservoir, the water-soluble polymer with good heat resistance and salt tolerance can be obtained through copolymerization between 2-acrylamide-2-methyl sulfonate monomer (AMPSN) and acrylamide monomer (AM) in water. The star shaped stable complexes (STARPAM) with the star nucleus of β-CD are prepared by living radical polymerization, which can improve the viscosity and change the percolation characteristics of the polymer in porous media. In the article, the performance of the STARPAM (star-shaped polymer) with heat resistance and salt tolerance was evaluated by comparing the viscosification property, heat and salt resistance, calcium and magnesium tolerance, and long-term thermal stability of STARPAM (star-shaped polymer) with those of HPAM (partially hydrolyzed polyacrylamide) and MO-4000 (linear polymer). The results of physical simulation experiment showed that the viscosity of the STARPAM is 3.3 times that of MO-4000 and 4 times that of HPAM under the conditions of mineralization degree of 20000 mg/L, concentration of 1500 mg/L, and 75°C, which indicated that heat resistance and salt tolerance of the STARPAM are excellent. Oil displacement experiments showed that STARPAM can enhance oil recovery by 20.53% after water flooding, and the effect of oil displacement is excellent. At present, 19 wells were effective with a ratio of 95.2%. Compared with before treatment, the daily liquid production increased by 136 m3, daily oil production increased by 44.6 t, water cut decreased by 4.67 percentage points, and flow pressure decreased by 1.15 MPa.


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