Polymers
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2019
·Vol. 11
·期 3
·540
·
IF 3.164
Qiang Li,Yanling Wang,Fuling Wang,Qingchao Li,Forson Kobina,Hao Bai,Lin Yuan
The low viscosity of pure liquid CO2hindered the development of CO2fracturing technology. A modified silicone polymer was prepared as a CO2thickener to investigate the effect of temperature, pressure, shear rate and thickener content (wt.%) on the apparent viscosity and rheology of thickened liquid CO2. In addition, CO2fracturing capacity was evaluated with the numerical simulation of extended finite element. The results displayed that an apparent viscosity of up to 1.3 mPa·s at 303 K and 18 MPa was attained over liquid CO2using the thickener of 3 wt.% and Toluene of 9 wt.% as additives. Compared to the commercial linear polydimethylsiloxane, a better apparent viscosity was obtained from the mixture of this prepared thickener, Toluene and CO2. The apparent viscosity decreases with increasing temperature and shear rate. By contrast, an improving apparent viscosity was revealed with an increase in the pressure from 8 to 14 MPa and thickener content from 1 to 3 wt.%. The rheological index decreased with increasing thickener content with pressure but the rise in temperature led to an increasing rheological index. The mesh structure theory of the thickener, CO2and Toluene molecules was in this paper gives a good explanation for the discrepancy between CO2viscosity with the thickener content, temperature, pressure, or shear rate. Compared to pure CO2, the numerical simulation of CO2fracturing demonstrated an excellent fracturing capacity by using the thickened CO2fracturing fluid in shale reservoirs. This investigation could provide the basic reference for the development of CO2fracturing technology.Keywords:polydimethylsiloxane;CO2thickener;CO2fracturing technology;oil and gas development engineering
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
POLYMER BULLETIN
·
2021
·Vol. 79
·期 6
·3665-3679
·
IF 2.87
Song Lizhi,Yuan Hui,Gong Yunlei,He Changlin,Zhou Hongyu,Wan Xiaojin,Qin Wei,Yang Sen,Ren Xianyan
Abstract With the increasing difficulty in exploitation of low-permeability, high water content and other unconventional reservoirs, a new kind of proppants that possess not only ultra-light weight and high strength and but also hydrophobic performances have attracted more and more interests. Here, this kind of proppants were designed and prepared successfully in the form of polymer microspheres. What's more is that the polymer microspheres (named O-MSDBs) showing high strength and stable hydrophobicity were prepared by a one-step suspension polymerization between styrene, divinyl benzene and γ-methacryloxypropyl-trimethoxy silane accompanying with the formation of silica through sol–gel process. When compared with reported ultra-lightweight proppants (ULWPs), the O-MSDBs not only perform better in ultra-lightweight (0.9917 g·cm −3 ) and are comparable in high strength (low crushing ratio of 0.89–2.53% at 55–69 MPa), but also show new hydrophobic function. The water contact angle on the surface of O-MSDBs is 140.7° that keeps about more than 80% after mechanical abrasion or acid dissolution. The one-step facile preparation method and brilliant performances make O-MSDBs very promising to large-scale preparation and widely applied in fracturing technology as proppants. Graphical Abstract
研究领域:
材料科学
·
石油工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2023
·Vol. 44
·期 12
·8454-8464
·
IF 5.2
Wei Qin,Yushan You,Yu Song,Jinrong Yin,Yang Zhou,Zhenyong Li,Zhen Zeng,Min Xu,Wenjiao Chen,Xianyan Ren
The polymer ultra-low-density proppants are critical to the development of slick-water fracture technology, but which were prone to obvious deformation under high pressure in the fractures. To increase the stiffness of the styrene-divinylbenzene copolymer (SDB) and obtain desired ultra-low-density (ULD) proppants, carbon dots (CDs) were introduced in-situ considering their characteristics as the zero-dimensional carbon nanomaterial. Taking the compressive strength and axial deflection, and so forth into consideration, the synthesis conditions of CDs modified SDB microspheres (CDs-SDBs) were optimized. Taking the graphite modified SDBs (MG-SDBs) as a reference, the density of CDs-SDBs did keep almost constant at about 1.1800 ~ 1.1899 g·cm −3 with the increase of CDs amount. The CDs-SDBs not only possess high-peak pressure (41.5 N) but also minute axial deflection (0.090 mm). The advantages of CDs-SDBs over MG-SDBs become even more pronounced under higher pressure, which can withstand closure pressure of 80 MPa with a small crush ratio of 4.47%. CDs-SDBs exhibit significant photoluminescence performances with maximum excitation and emission wavelengths of 634 nm and 554 nm. Highlights CDs-SDBs as ULD proppants with high strength and anti-deformation were developed. Advantages of CDs-SDBs become more pronounced under high-closure pressure. With increasing of CDs amount, apparent density of CDs-SDBs keep almost constant. Axial deflection of CDs-SDBs is only 0.09 mm under 41.5 N. The crush ratio is only 4.47% under 80 MPa closure pressure.
研究领域:
材料科学
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石油工程
·
纳米技术
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Huina Qin,Huixiong Wu,Ying Wang,Jiayi Tan,Ruiquan Liao,Zhixiong Ma
To overcome the limitations of traditional gels in low-temperature refracturing applications, a novel low-temperature self-degrading gel (LT-SDG) was developed. The gel is based on an acrylamide–acrylic acid copolymer crosslinked with SEG and initiated by a thermal APS/SHS system. It forms a robust 3D network at 35–40 °C and degrades spontaneously without external breakers. The formulation was optimized by investigating the effects of monomer concentration, crosslinker content, initiator ratio, and neutralization degree on gelation, strength, and degradation. Structural and thermal properties were characterized via FTIR, DSC, and SEM. Experimental results demonstrated that the optimized LT-SDG achieves gelation within 1.5–3 h, reaches a strength grade of H–I, and degrades into a low-viscosity fluid within 200–500 h. Mineralization tests showed that Na + accelerated degradation via charge shielding, while Ca 2+ enhanced network stability through ionic crosslinking. Sand-packed tube and core flooding experiments confirmed excellent plugging performance (>99.5 %) and high pressure-bearing capacity, with permeability recovery reaching 93.77 % after full degradation. Moreover, LT-SDG exhibited good compatibility with guar-based fluids and slickwater, ensuring stable performance under field conditions. These results indicate that LT-SDG provides clean, efficient, and controllable zonal isolation in low-temperature reservoirs, offering a promising solution for diversion fracturing in mature wells.
研究领域:
石油工程
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压裂技术
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高分子材料
·
储层改造
✓ 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）