FUEL
·
2021
·
IF 6.609
Xinjie Luo,Pengfei Zheng,Ke Gao,Bing Wei,Yujun Feng
Water-alternating-CO 2 gas (WAG) flooding is a common technique to enhance oil recovery via improving CO 2 sweep efficiency, but serious gas channeling may still occur, especially in reservoirs with strong heterogeneity, due to a poor blocking capacity of aqueous slugs to the “channeling” pathway induced by their low viscosity. Herein, a copolymer whose aqueous solution viscosity can be increased by both heat and CO 2 was developed and added into the aqueous slug to control gas channeling and increase oil recovery during enhanced WAG processes. The copolymer was synthesized by grafting poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) onto the triblock copolymer, Pluronic F127, PEO 100 -PPO 65 -PEO 100 . The aqueous copolymer solutions can be thickened/gelled by heating due to the formation of micelles as the physical cross-link and their entanglements even at a concentration as low as 0.2 wt%, and viscosified by bubbling CO 2 thanks to expanded copolymer coils caused by electrostatic repulsion-induced chain extension of protonated PDMAEMA chains. Notably, thermo- and CO 2 -triggered viscosifying can work synergistically and they are completely reversible upon cyclically heating/cooling the copolymer solutions and bubbling/removing CO 2 into/from the aqueous phase, respectively. In WAG flooding tests using two parallel cores, gas channeling was mitigated by blocking high-permeability cores due to in-situ thermo-induced gelation and CO 2 -triggered thickening of copolymer slugs, thus diverting chase fluids into unswept low-permeability cores and enhancing 21–22% total oil recovery than the conventional and HAPM-enhanced WAG modes. Importantly, owing to the characteristics of low initial viscosity, single component, and thermo-gelation, this dually-responsive copolymer possesses high injectivity and satisfactory gelation control. This work could enlighten the design of novel dual/multiple stimuli-thickening polymers used for channeling control and enhanced oil recovery.
研究领域:
石油工程
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Yue Gu,Hongjun Tu,Ming Zhou
In this paper, a biobased ternary composite microgel (CS-DP-AA) was designed and prepared, which was based on chitosan and had a reversible response to CO2. The synthesis of CS-DP-AA microgel was proved by infrared spectroscopy, chromatography–mass spectrometry, X-ray photoelectron spectroscopy, and Raman spectroscopy. The structure and properties of CS-DP-AA microgel before and after CO2 response were characterized by scanning electron microscope, transmission electron microscope, ultraviolet visible spectrophotometer, laser particle size analyzer, zeta potentiometer, and other instruments, and the CO2 response mechanism was explored. The results show that CS-DP-AA microgel had great CO2 response performance and stability, and the UV transmittance could still reach 90.01% (relative) at 268.98 h after CO2 response. Subsequently, the rheological properties of CS-DP-AA microgel were evaluated by a rotary rheometer, which shows that CS-DP-AA microgel after the CO2 response had obvious viscoelasticity. Although shear thinning appeared with the increase in shear rate, the CS-DP-AA microgel after the CO2 response still had good viscosity under high temperature, high pressure, and high shear rate, which proves that it had great rheological properties. On the other hand, the ability of CS-DP-AA microgel to plug gas channeling in reservoirs was evaluated by a dual-core parallel-core physical simulation experimental device. The results show that the CS-DP-AA microgel injected into the core can indeed react with the CO2 adsorbed in the pores of the porous core and plug the larger pores. After the response, the resistance coefficient of the system increased significantly, reaching 80 times that of the previous value. It has been shown that CS-DP-AA microgel can indeed block gas channeling in oil reservoirs, expand the sweep efficiency and swept volume of the CO2 gas drive, contribute to the recovery rate of oil reservoirs, and ensure the smooth development of oil reservoirs, which has a good application prospect in plugging gas channeling in oil reservoirs.
研究领域:
材料科学
·
石油工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2025
·
IF 1.9
M. L. Shao,M. J. Cheng,J. Gong,A. L. Chang,L. P. Fu,K. L. Liao,X. Q. Liu
Carbon dioxide (CO2) flooding is one of the efficacious channels to enhance oil recovery efficiency of low permeability reservoirs. However, CO2 gas channeling has seriously affected the development effect due to severe formation heterogeneity. Nanomaterials have good application prospects in plugging gas channeling, but the dispersibility in water limits the plugging effect. In this paper, a nanoparticle plugging agent with a core-shell architecture was synthesized via emulsion polymerization. The impacts of different elements such as grain diameter, temperature and salinity on the swelling characteristic of nanoparticles were studied respectively. Subsequently, the CO2 response property of nanoparticles was tested by uniformly injecting CO2. Finally, based on the calculation of molecular dynamics, the interaction between nanoparticles and water molecules was analyzed. The results showed that the CO2-responsive nanoparticles exhibit a lower swelling ratio (<5), and the residual resistance coefficient is 2.47, demonstrating a limited expansion property and superior plugging performance. The interaction between protonated nanoparticles and water molecules was stronger, resulting in enhanced hydrophilicity and responsive inflation of nanoparticles. The system has great potential application prospects for in-depth CO2 conformance control.
研究领域:
石油工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Gels
·
2025
·Vol. 11
·期 5
·350
·
IF 5.3
Junwei Fang,Jinsheng Sun,Xingen Feng,Lijuan Pan,Yingrui Bai,Jingbin Yang
Gas channeling phenomena in carbonate fracture-vuggy reservoirs frequently occur, primarily in the form of negative pressure gas channeling and displacement gas channeling, with the possibility of mutual conversion between the two. This is accompanied by the risk of hydrogen sulfide (H 2 S) release from the reservoir, which poses significant challenges to controlling safety. Currently, liquid bridging and gel plugging technologies are effective methods for mitigating complex issues such as downhole overflow, fluid loss, and heavy oil backflow. This paper focuses on the development and optimization of key treatment agents, including high-temperature-resistant polymers and crosslinking agents, to formulate a high-temperature chemical gel plugging agent. A gel-breaking, high-strength colloidal chemical gel plugging agent system capable of withstanding temperatures up to 150 °C was developed, and it has an apparent viscosity of about 7500 mPa·s, an energy storage modulus and a loss modulus of 51 Pa and 6 Pa, respectively, after gel formation at elevated temperatures, and an apparent viscosity retention rate of the gel of greater than 82% after aging for 9 d at a temperature of 150 °C. This system forms a stable gas isolation barrier in the wellbore, with performance remaining stable after 7 to 12 days of aging, and the degradation rate reaches 99.8% after 24 h at 150 °C. This technology is of significant importance in solving complex issues such as overflow, fluid loss, and heavy oil backflow in gas injection and recovery wells in high-temperature, high-pressure reservoir conditions.
研究领域:
石油工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
·
2022
·
IF 5.168
Qixin Liu,Changlong Liu,Yuan Li,Na Fang,Xiang Yan,Caili Dai,Yongping Huang,Yining Wu
Gas flooding is an effective EOR process for carbonate fractured-vuggy reservoirs worldwide. With the large-scale application of gas flooding, the problem of gas channeling is emerging inevitably and restricts the improvement of oil recovery. Foaming can alleviate such problems due to its high viscosity. However, many factors lead to the poor stability of conventional foam or even gelled-foam in fractured-vuggy reservoirs, such as Ostwald maturation, lack of support from pore-throat units, and weak regeneration ability, dilution of formation water, high temperature, high salinity , etc. Therefore, a novel dual network semi-solidified gelled-foam was designed to solve the gas channeling problem in fractured-vuggy reservoirs. It overcomes the shortcoming of fast foam volume attenuation due to temperature rising. The new foam system consists of an ionic crosslinking network (sodium alginate , Ca 2+ ) and a covalent crosslinking network (acrylamide, polyacrylamide, crosslinking agent). The characteristics of sodium alginate, which can rapidly react with divalent cations (Ca 2+ ) in formation water to generate an ionic crosslinking network, forming a protective film to enhance foam stability in the first stage. Acrylamide, polyacrylamide, and crosslinking agent (methenamine and resorcinol) were used to form the second network (covalent crosslinking network), which can effectively enhance the high temperature stability of the foam. After optimization, the dual network semi-solidified gelled-foam was obtained, and the half-life can reach 15d in a high temperature and high salinity environment (130 °C, 22.37 × 10 4 mg/L). Meanwhile, the new foam system also showed higher viscosity, high oil tolerance and plugging capability. This unique designed gelled-foam offers high application potential in deep fractured-vuggy reservoirs. It effectively solves the gas channeling problem in gas flooding production in fractured-vuggy reservoirs worldwide.
研究领域:
石油工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
·
2022
·
IF 5.168
Bobo Zhou,Wanli Kang,Haizhuang Jiang,Hongbin Yang,Zhe Li,Zhiqi Lv,Zhe Xu,Changyuan Ning,Huazheng Wang,Shuting Xie
CO 2 flooding is often used in low permeability reservoirs , but there is general fracture in the reservoir, resulting in the problem of gas channeling. To achieve anti-gas channeling in deep formation, acrylamide (AM), sodium p-styrenesulfonate (SSS) and dimethyl diallyl ammonium chloride (DMDAAC) were used as functional monomers , N′ N-methylene bisacrylamide (MBA) and polyethylene glycol 200 diacrylate (UCA) were used as crosslinking agents, a double-crosslinking nano polymer gel microsphere (DCNPM-A) was synthesized by inverse microemulsion polymerization. The synthetic process of gel microsphere was optimized by initial particle size and swell multiple (defined the ratio of gel microsphere volume after and before water absorption) as evaluation indexes. The gel microsphere was characterized by scanning electron microscopy (SEM) and elemental analysis (EDS). The anti-gas channeling ability was evaluated by one-dimensional fracture core. The structure of the copolymer without crosslinking agent was verified by 1 H NMR. The results showed that the DCNPM-A gel microsphere was regular spherical shape under the optimal synthesis process, and EDS analysis showed that the microsphere contained all the characteristic elements of monomers. The initial particle size and swell multiple of DCNPM-A gel microsphere were 217.3 nm and 13.5 respectively. The gel microsphere possessed delayed swelling. The plugging rate of DCNPM-A gel microsphere was 95.48% in the anti-gas channeling experiment. The study in this paper can provide theoretical support for the anti-gas channeling in low-permeability fracture reservoirs.
研究领域:
石油工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Geoenergy Science and Engineering
·
2025
·
IF 4.6
Hongbin Yang,Haocong Li,Hao Xu,Ruichao Wang,Yubin Zhang,Luyao Xing,Xin Chen,Liang Peng,Wanli Kang,Bauyrzhan Sarsenbekuly
CO 2 foam flooding is an effective enhanced oil recovery (EOR) technique that has been extensively studied for development of low-permeability reservoirs. However, during its application, poor foam stability often leads to severe gas channeling, resulting in lower recovery. In order to improve the foam stability, a CO 2 foam system was constructed by using fluorescent nano polymer microspheres (PARC(Flu-Ac)-5) and anionic surfactant sodium α-alkene sulfonate (AOS). The macroscopic and microscopic stability of the CO 2 foam system stabilized by PARC(Flu-Ac)-5 was investigated through its rheological properties, adsorption characteristics, and microscopic morphology. Furthermore, the sweep range of different foam systems and the stability of the foam in the channel were explored through the microscopic visualization model. Finally, the plugging and oil displacement performance of the CO 2 foam system stabilized by fluorescent nano polymer microspheres was evaluated through dynamic core flooding experiments conducted under CO 2 flooding reservoir conditions. Thus, the oil displacement mechanism of fluorescent nano polymer microspheres stabilizing CO 2 foam was revealed. The experimental results demonstrate that PARC(Flu-Ac)-5 microspheres greatly enhance the stability of CO 2 foam by adsorbing at the gas-liquid interface. It remains stable for 30 min when formed with 5 % oil content. The microspheres' distinctive elastic deformation characteristics enable their migration and subsequent plugging of the pores following foam rupture, thereby establishing a dual anti-gas channeling mechanism. The total recovery of CO 2 foam system stabilized by fluorescent nano polymer microspheres is 46.71 %. The oil displacement effect is better than that of the single AOS foam system, and the total recovery rate is increased by 12.02 %. By adsorbing at the gas-liquid interface of foam liquid film, PARC(Flu-Ac)-5, acting as a foam stabilizer, enhances both the stability and oil resistance of foam within porous media. This adsorption behavior thereby enabling the foam to maintain its integrity upon encountering crude oil and preventing foam coalescence and defoaming. Concurrently, under the Jamin effect of the foam, the foam preferentially occupies the pore space in high permeability layers, and the injected fluid is diverted toward unswept regions following the plugging of high permeability pathways. Consequently, the sweep range and the driving ability of the subsequent foam to enter the blind end are increased, and the recovery rate of crude oil is improved. This work lays a theoretical foundation for the field application of polymer microspheres stabilized CO 2 foam system.
研究领域:
石油工程
·
提高采收率
·
胶体与界面科学
·
多孔介质流体动力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）