Gels
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2023
·Vol. 9
·期 5
·387
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IF 4.6
Kaihe Lv,Guodong Zhang,Yingrui Bai,Jingbin Yang
A common problem associated with conventional gel breakers is that they can cause a premature reduction in gel viscosity at high temperatures. To address this, a urea-formaldehyde (UF) resin and sulfamic acid (SA) encapsulated polymer gel breaker was prepared via in situ polymerization with UF as the capsule coat and SA as the capsule core; this breaker was able to withstand temperatures of up to 120–140 °C. The encapsulated breaker was characterized using scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and thermogravimetric (TG) analysis. Meanwhile, the dispersing effects of various emulsifiers on the capsule core, and the encapsulation rate and electrical conductivity of the encapsulated breaker were tested. The gel-breaking performance of the encapsulated breaker was evaluated at different temperatures and dose conditions via simulated core experiments. The results confirm the successful encapsulation of SA in UF and also highlight the slow-release properties of the encapsulated breaker. From experimentation, the optimal preparation conditions were determined to be a molar ratio between urea and formaldehyde (nurea:nformaldehyde) of 1:1.8 for the capsule coat, a pH of 8, a temperature of 75 °C, and the utilization of Span 80/SDBS as the compound emulsifier; the resulting encapsulated breaker exhibited significantly improved gel-breaking performance (gel breaking delayed for 9 days at 130 °C). The optimum preparation conditions determined in the study can be used in industrial production, and there are no potential safety and environmental concerns.Keywords:encapsulated breaker;in situ polymerization;gel temporary plugging;delayed gel breaking
研究领域:
材料科学
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化学工程
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DOI
PubMed
高影响因子
Geoenergy Science and Engineering
·
2024
·
IF 0
Renjing Ji,Xiaorong Yu,Huan Yang,Xiying Wang,Gaoshen Su
As an effective drilling pressure control technology, the gel valve offers a potential alternative to casing valves by utilizing its own strength to isolate downhole pressure. This paper presents a self-breaking gel valve synthesized using acrylamide and degradable crosslinker, which addresses drawbacks of existing gel-breaking techniques, such as time consumption and incomplete breaking. Firstly, the effects of monomer concentration, initiator concentration, and degradable crosslinker concentration on the performance of the gel valves were investigated. The results indicate that the gelation time can be controlled within 1–3 h, while maintaining degradation time control within 5–20 days at 90 °C. Then the pressure-bearing capacity and the effect of temperature on the degradation properties of the self-breaking gel valve were evaluated. The average pressure-bearing gradient of the gel valve at 90 °C can reach to 0.66 MPa/m. More importantly, the mechanism of gel breaking was studied. The results show that the ester groups hydrolyze gradually during the degradation process, leading to fracture of the crosslinking point inside the gel valve, a reduction in binding degree of intermediate water within the gel valve, and a decrease in crosslinking density. Additionally, there is a change in microstructure from a regular dense three-dimensional network structure to a linear random structure. The self-breaking gel valve eliminates the need for subsequent gel-breaking operations, reducing costs and preventing pollution from chemical gel-breaking agents. The self-breaking gel valve is expected to be used in pressure control for whole process underbalanced drilling.
研究领域:
石油工程
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材料科学
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DOI
ENERGY & FUELS
·
2024
·
IF 5.2
Mingwei Zhao,Ziteng Yang,Xiangjuan Meng,Xudong Wang,Zhiwei Wang,Zhongzheng Xu,Yining Wu,Caili Dai
Weighted gel fracturing fluid has been recognized as a crucial technology to address the challenges of abnormally high pressure and ultrahigh temperature reservoir stimulation in the deep oil and gas exploration and development process. Herein, a NaBr weighted gel fracturing fluid with delayed cross-linking properties and good temperature resistance is developed by selecting the type of weighting materials and optimizing the concentration of the fracturing fluid main agents. The results indicated that the density of the weighted gel fracturing fluid is up to 1.372 g/cm3. When both thickener and cross-linking agent concentrations reach 0.8 wt %, the fracturing fluid can meet the temperature and shear resistance requirements at 200 °C and 100 s–1. More importantly, the weighted gel exhibits significant delayed cross-linking properties, and the cross-linking is complete within 266 s. Through the multicycle strain oscillation scanning test, steady shear test, and microscopic characterization, it was confirmed that the weighted gel has exceptional self-healing properties from the macroscopic properties and microstructure, and a dense cross-linking network structure exists. In addition, the gel breaking effect of different gel breakers on the weighted gel fracturing fluid is discussed. The ammonium persulfate breaker with strong oxidation can effectively damage the weighted gel. We expect that this study can provide new ideas for the application of weighted gel fracturing fluid in abnormally high pressure and ultrahigh temperature reservoirs and provide a theoretical basis for field practice.
研究领域:
石油工程
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材料科学
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DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 3
·397
·
IF 4.7
Yubin Liao,Jicheng Jin,Shenglin Du,Yufei Ren,Qiang Li
Clean fracturing fluid has the characteristics of being environmentally friendly and causing little damage to reservoirs. Meanwhile, its backflow gel-breaking fluids (GBFs) can be reutilized as an oil displacement agent. This paper systematically evaluates the feasibility and EOR mechanism of a GBF based on a polymer surfactant as an oil displacement system for reutilization. A rotating interfacial tensiometer and contact angle measuring instrument were used to evaluate the performance of reducing the oil–water interfacial tension (IFT) and to change the rock wettability, respectively. Additionally, a homogeneous apparatus was used to prepare emulsions to evaluate GBF’s emulsifying properties. Finally, core flooding experiments were used to evaluate the EOR effect of GBFs, and the influence rules and main controlling effects of various properties on the EOR were clarified. As the concentration of GBFs increases, the IFT first decreases to the lowest of 0.37 mN/m at 0.20 wt% and then increases and the contact angle of the rock wall decreases from 129° and stabilizes at 42°. Meanwhile, the emulsion droplet size gradually decreases and stabilizes with increases in GBF concentration, and the smallest particle size occurs when the concentration is 0.12–0.15 wt%. The limited adsorption area of the oil–water interface and the long molecular chain are the main reasons that limit the continued IFT reduction and emulsion stability. The oil displacement experiment shows that the concentration of GBF solution to obtain the best EOR effect is 0.15 wt%. At this concentration, the IFT reduction and the emulsification performance are not optimal. This shows that the IFT reduction performance, reservoir wettability change performance, and emulsification performance jointly determine the EOR effect of GBFs. In contrast, the emulsifying performance of GBFs is the main controlling factor for the EOR. Finally, the optimal application concentration of GBFs is 0.15–0.20 wt%, and the optimal injection volume is 0.5 PV.
研究领域:
石油工程
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化学工程
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DOI
PubMed
高影响因子
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
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2021
·
IF 4.346
Chen Wang,Guanjun Qiu,Xueli Long,Tao Wang,Xing Zhang,Lidong Liang,Jianguang Bai,Zhigang Li,Liewei Qiu,Xiaowu Yang,Kang Zhang
Hooked gemini viscoelastic surfactant (HGVES) was designed and synthesized by reactions of linolenic acid with 3-(Dimethylamino)-1-propylamine, 3-Chloro-2-hydroxypropanesulfonic acid sodium salt and isophorone diisocyanate. The structure was characterized by FT-IR and 1 HNMR. The properties of HGVES were compared with gemini viscoelastic surfactant (GVES) by surface tension, transmittance, rheological behavior, dynamic light scattering and SEM. The result showed that the fracturing performance of HGVES was superior to that of GVES. The critical micelle concentrations (CMC) of HGVES and GVES were 7.69 × 10 −5 and 9.68 × 10 −5 mol/mL, respectively. Rheological experiments showed that HGVES and GVES were pseudoplastic fluids and HGVES had better viscoelastic behavior. Proppant suspension experiments showed that support suspension performance decreased with the temperature increasing, and the static setting rate was 0.1013 mm/s when the temperature was at 80 °C. Meanwhile, the mechanisms of different gel-breaking agents were also studied, comparing with HGVES and gel-breaking products by FT-IR, 1 HNMR, rheological behavior and SEM. The results showed that hydrocarbon oil gel-breaking agents would not destroy the molecular structure of HGVES, while strong oxidant gel-breaking would destroy the double bond of carbon. NaHSO 3 would have addition reaction with double bond. The core damage permeability of 2 wt% HGVES was 5.35%, and there was no residue in all gel-breaking solutions. Therefore, this kind of hooked gemini viscoelastic surfactant can be used in oil fracturing to improve oil recovery.
研究领域:
石油工程
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化学工程
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材料科学
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DOI
高影响因子
Gels
·
2022
·Vol. 8
·期 10
·600
·
IF 4.432
Peng Liu,Caili Dai,Mingwei Gao,Xiangyu Wang,Shichun Liu,Xiao Jin,Teng Li,Mingwei Zhao
In order to broaden the application of clean fracturing fluid in ultra-high temperature reservoirs, a surfactant gel for high-temperature-resistant clean fracturing fluid was developed with a gemini cationic surfactant as the main agent in this work. As the fracturing fluid, the rheological property, temperature resistance, gel-breaking property, filtration property, shear recovery performance and core damage property of surfactant gel were systematically studied and evaluated. Results showed the viscosity of the system remained at 25.2 mPa·s for 60 min under a shear rate of 170 s−1at 200 °C. The observed core permeability damage rate was only 6.23%, indicating low formation damage after fracturing. Due to micelle self-assembly properties in surfactant gel, the fluid has remarkable shear self-repairability. The filtration and core damage experimental results meet the national industry standard for fracturing fluids. The gel system had simple formulation and excellent properties, which was expected to enrich the application of clean fracturing fluid in ultra-high temperature reservoirs.Keywords:clean fracturing fluid;VES;surfactant gel;rheology behavior;thermal stability
研究领域:
石油工程
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化学工程
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材料科学
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DOI
PubMed
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Kaiyu Zhang,Guodong Zhang,Zhuojing Li,Jirui Hou
Low pH fracturing fluids, such as the transition metal cross-linked guar derivative, can reduce the formation damage caused by clay swelling and fines migration in hydraulic fracturing treatments. However, a major disadvantage of the fluids is the uncontrollable rapid viscosity development, especially cross-linking under a pH below 3.0. In this paper, a novel delayed organic zirconium cross-linker with lactate and ethylene glycol as ligands was designed to overcome the shortcoming. Carboxymethyl hydroxypropyl guar (CMHPG), which results in a low gel residue after breaking, was used as the polymer at low concentration. The impact of gelation parameters on the properties of zirconium-CMHPG gel system was systematically investigated using a Sydansk bottle-testing method combined with a controlled stress rheometer. Desirable gelation time delay with agreeable rheological performance could be obtained by optimizing the polymer and cross-linker concentrations even at a pH as low as 2.0. Uniformly and compactly generated 3D network microstructures could firmly lock the free water within the gel, which further improved the thermostability and acid-resistance of the system. Meanwhile, the structures could also maintain the viscoelasticity of the fluid at a high level to ensure the efficient transportation of the proppants. Proppant settling and gel breaking tests demonstrated that the low pH and low polymer concentration gel system generated fewer insoluble residues with an uncompromised suspension performance. Moreover, the formation damage evaluation revealed that the low pH fracturing fluid system produced a better return permeability than the high pH system.
研究领域:
石油工程
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化学工程
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Wenlong Zhang,Yonghao Chen,Jizhen Tian,Dong Wang,Hao Zeng,Longyao Wang,Hetian Su,Jincheng Mao,Xiaojiang Yang
The study presents a groundbreaking advancement in variable-viscosity slickwater technology for unconventional reservoir stimulation through the development of a novel hydrophobically associating water-soluble polymer (TAE 23 C 12 N) and its synergistic systems with viscoelastic surfactants (VESs), which successfully addresses the challenge of real-time preparation of polymer powder-based slickwater. The innovative pentameric copolymer, synthesized via strategic incorporation of lauryl polyoxyethylene ether methacrylate, AMPS, and sulfobetaine monomers, demonstrates exceptional performance characteristics, including a high molecular weight (5.59 × 10 6 g/mol), superior salt tolerance (>10 4 mg/L mineralization resistance), and excellent thermal stability (50 % mass loss at 393 °C). A custom-designed continuous powder-liquid mixing system enabled real-time preparation of polymer powder-based slickwater, effectively solving the critical issue of polymer powder hydration and positioning TAE 23 C 12 N as a superior alternative to conventional emulsion and suspension dispersion systems for slickwater formulation. This technological breakthrough offers significant advantages, including reduced operational costs, minimized formation damage (<16.39 % permeability reduction), and enhanced transportation efficiency. Comprehensive characterization revealed remarkable synergistic effects between TAE 23 C 12 N and three VESs in polymer powder-based slickwater systems, with the EDAC/TAE 23 C 12 N system exhibiting optimal performance: rapid preparation (34 s for low-viscosity formulation), maximum drag reduction (79.1 %), and robust thermal/shear stability. All VES-enhanced polymer powder-based slickwater systems demonstrated complete gel breaking within 2 h at 120 °C, meeting stringent industry standards. These advancements address critical challenges in hydraulic fracturing through enhanced proppant transport, reduced environmental impact, and cost-effective large-scale applications of polymer powder-based slickwater, representing a paradigm shift in fracturing fluid technology with potential applications extending to enhanced oil recovery and geothermal energy development.
研究领域:
石油工程
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能源资源
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材料科学
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化学工程
·
储层改造
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Mingwei Zhao,Shichun Liu,Zhibin Gao,Yining Wu,Caili Dai
The quick flowback treatment after conventional fracturing construction can waste a lot of energy from fracturing fluid . Meanwhile, spontaneous imbibition has great application potential for enhanced oil recovery (EOR). In this work, based on pre-developed silica nanoparticle-reinforced CO 2 -sensitive fracturing fluid system, the imbibition factors of the gel breaking fluid were studied. In addition, the HNMR technology, AFM , contact angle test, and interfacial tension (IFT) test were used to explore the mechanism of spontaneous imbibition. The results show that imbibition mainly occurs in the small pores, and the adsorption of components can reduce roughness and flow resistance. Meanwhile, the adsorption layer was formed by surfactants and nanoparticles, changing wettability from oil-wet to water-wet, reducing the IFT between oil and water. The synergistic effect of multi-component improves the imbibition effect. We expect that this study can broaden the application of multi-component gel breaking fluid in low permeability reservoirs .
研究领域:
石油工程
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材料科学
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化学工程
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产品关联
DOI
高影响因子
Petroleum Science
·
2023
·
IF 5.6
Xiang-Yu Wang,Ming-Wei Zhao,Xu-Hao Wang,Peng Liu,Meng-Yao Fan,Teng Li,Zhen-Feng Ma,Ying-Jie Dai,Cai-Li Dai
Fracturing fluid property play a critical role in developing unconventional reservoirs. Deep eutectic solvents (DESs) show fascinating potential for property improvement of clean fracturing fluids (CFFs) due to their low-price, low-toxicity, chemical stability and flexible designability. In this work, DESs were synthesized by mixing hydrogen bond acceptors (HBAs) and a given hydrogen bond donor (HBD) to explore their underlying influence on CFF properties based on the intermolecular interactions. The hydrogen-bonding, van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength. The HBD enhanced the resistance of CFF for Ca 2+ due to coordination-bonding interaction. The DESs composed of choline chloride (ChCl) and malonic acid show great enhancement for surface, rheology, temperature resistance, salt tolerance, drag reduction, and gel-breaking performance of CFFs. The DESs also improved the gel-breaking CFF-oil interactions, increasing the imbibition efficiencies to 44.2% in 74 h. Adjusting HBAs can effectively strengthen the intermolecular interactions (e.g., HBA-surfactant and HBD-surfactant interactions) to improve CFF properties. The DESs developed in this study provide a novel strategy to intensify CFF properties.
研究领域:
石油工程
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化学工程
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材料科学
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DOI
高影响因子
PLoS One
·
2021
·Vol. 16
·期 3
·e0247948
·
IF 3.24
Shiliang Xu,Mengke Cui,Renjie Chen,Qiaoqing Qiu,Jiacai Xie,Yuxin Fan,Xiaohu Dai,Bin Dong
With the increasing demand for energy, fracturing technology is widely used in oilfield operations over the last decades. Typically, fracturing fluids contain various additives such as cross linkers, thickeners and proppants, and so forth, which makes it possess the properties of considerably complicated components and difficult processing procedure. There are still some difficult points needing to be explored and resolved in the hydroxypropyl guar gum (HPG) removal process, e.g., high viscosity and removal of macromolecular organic compounds. Our works provided a facile and economical HPG removal technology for fracturing fluids by designing a series of processes including gel-breaking, coagulation and precipitation according to the diffusion double layer theory. After this treatment process, the fracturing fluid can meet the requirements of reinjection, and the whole process was environment friendly without secondary pollution characteristics. In this work, the fracturing fluid were characterized by scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy technologies, etc. Further, the micro-stabilization and destabilization mechanisms of HPG in fracturing fluid were carefully investigated. This study maybe opens up new perspective for HPG removal technologies, exhibiting a low cost and strong applicability in both fundamental research and practical applications.
研究领域:
石油工程
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）