JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2022
·
IF 2.042
Chengzhang Cao,Yuhuan Bu,Leiju Tian,Laiju Han
Compared with cement stone, epoxy resin has a higher compressive strength, lower elastic modulus, and better seepage capacity in repairing cement sheath or cementing in special formations. The viscosity of epoxy resin is significantly affected by temperature, which causes a serious decrease in the settlement stability. In this study, the effects of the diluent, solid epoxy resin and rheological agents on the slurry viscosity, and settlement stability were evaluated. The results indicate that fumed silica and organic bentonite have a good effect on improving the settlement stability, but have negative effects on pumpability. Therefore, a method to improve the settlement stability of epoxy resin-based cementing slurry was developed. Fumed silica and organic bentonite were compounded to increase the settlement stability and lower dosage (fumed silica less than 3 wt.%) can avoid too much negative effect on pumpability. Viscosity tests showed that diluent work more effectively at low temperatures while solid ER and Xanthan gum are more effective at high temperatures. When they use together, the viscosity at 90 °C is increased by 33% while decrease by 86% at 25 °C. When the temperature increases downhole, the viscosity of diluent is closed to ER, and tackifying materials dominate, increasing the viscosity at high temperatures. Based on the method proposed in this paper, the epoxy resin-based cementing slurry can increase the settlement stability to less than 0.01 g/cm3 when the slurry density is less than 1.3 g/cm3 and a settlement stability of less than g/cm3 when slurry density is less than 1.59 g/cm3 .
研究领域:
石油工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2022
·Vol. 15
·期 12
·4197
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IF 3.252
Guokun Yang,Tianle Liu,Hai Zhu,Zihan Zhang,Yingtao Feng,Ekaterina Leusheva,Valentin Morenov
This study aims to develop a novel low-heat cement slurry using phase change microcapsule additives to reduce the decomposition of hydrate-bearing sediments during cementing. Microcapsules were prepared by coating mixed alkanes with polymethyl methacrylate, and lipophilic-modified graphite was incorporated to enhance the thermal conductivity of microcapsules. The effects of microcapsules upon the hydration heat, pore distribution, and compressive strength of the cement slurry/stone were studied through a variety of tests. The results showed that the phase-change temperature, thermal enthalpy, and encapsulation efficiency of the microcapsules were 8.99–16.74 °C, 153.58 Jg−1, and 47.2%, respectively. The introduction of lipophilic-modified graphite reduced the initial phase-change temperature of microcapsules by 0.49 °C, indicating an improvement in their temperature sensitivity. The maximum hydration heat of cement slurry decreased by 41.3% with 7% dosage of microcapsules; the proposed microcapsules outperformed comparable low-heat additives. Moreover, the presence of microcapsules could reduce the number of large pores in (and thereby improve the compressive strength of) cement stone. The innovation of this study is that it comprehensively and intuitively confirms the feasibility of the application of low-heat cement slurry with MPCM as the key in hydrate sediments rather than just focusing on the reduction of hydration heat; furthermore, a self-made cementing device was developed to simulate the cementing process of hydrate deposition. The results show that the thermal regulation of microcapsules inhibited the temperature increase rate of the cement slurry, significantly reducing the damage caused to the hydrate. These findings should improve the safety and quality of cement in offshore oil and gas well applications.Keywords:microencapsulated phase-change materials;heat control;temperature sensitivity;cementing;hydration heat;natural gas hydrate-bearing sediment
研究领域:
土木工程
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材料科学
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海洋工程
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产品关联
DOI
高影响因子
FUEL
·
2024
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IF 6.7
Yuhuan Bu,Zilong Lu,Chang Lu,Huajie Liu,Shenglai Guo,Hexing Liu,Rui Ma,Zhen Zhang,Mengran Xu
Deepwater cementing technology holds non-negligible significance in ensuring the safe exploitation of deepwater oil and gas resources, and maintaining stability of hydrate formations is crucial for deepwater cementing. Traditional solutions primarily focus on reducing the cement’s hydration heat evolution but fail to effectively address the issue of hydrate dissociation. Therefore, our previous work outlined the design and optimization of a novel hydrate dissociation inhibitor, PVCap/dmapma, and its physical synthesis and evaluation are explored in this study. The method of molecular simulation and experimental study was utilized to establish an evaluation method of hydrate dissociation inhibitor under cementing environment, to investigate the hydrate decomposition inhibitory, and to determine the relatively optimal synthesis conditions and process. PVCap/dmapma exhibits excellent ability to delay the hydrate dissociation, and no adverse effects on cement thickening and mechanical properties compared to Lecithin. Our findings provide a certain theoretical foundation for the development of hydrate dissociation inhibitors for cementing and hold significant implications for ensuring the safe exploitation of deepwater oil and gas resources.
研究领域:
石油工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2025
·Vol. 15
·期 1
·1-19
·
IF 3.9
Zhu Wenxi,Wang Bingjie,Cui Shengkai,Wang Jing,Tan Huijing
Effective heat transfer between the working fluid and subterranean rocks is essential for producing green and low-carbon geothermal energy. As the primary thermal conductive medium, cement has low thermal conductivity, leading to high thermal resistance and significantly reducing geothermal wells’ efficiency. Therefore, high thermal conductivity cement has emerged as a widely anticipated new research area. The purpose of this research is to address the substantial harm of traditional carbon-based thermal conductive fillers to cement. A novel expanded graphite (EG)/epoxy resin (EP) composite additive (MEG) was designed to increase cement’s thermal conductivity while preserving its mechanical strength and pumpability. Firstly, the physicochemical properties of MEG were revealed by FT-IR, UV-Vis, SEM, and TGA. Then, the applicability of MEG cement in adverse geological environments (high-temperature 60–100 ℃, high-mineralization 5–36% NaCl) was evaluated through simulated maintenance experiments. Finally, the hydration products and pore structure of MEG-cement were analyzed by XRD/FT-IR and SEM/MIP, revealing the thermal conductivity enhancing mechanism. The results showed that: 1) MEG uses ZDMA as a bridge to promote the ring opening and curing of EP, and is formed by strong cation -π interaction with EG. 2)After curing at 60–100 ℃, MEG-cement exhibits a significant increase (46.6-182.1%) in thermal conductivity within the optimal dosage range of 5–10%, fully meeting the requirements for compressive strength (10.4–21.7 MPa) and fluidity (19.3–21.2 cm) of cementing. In addition, MEG-cement maintained stable density and significant high thermal conductivity advantage in high-mineralization environments (5–36% NaCl), with an increase in thermal conductivity of 23.8- 54.1%. 3) The mechanism of MEG promoting heat transfer in cement is summarized as the enhancement of the hydration process and the production of C-S-H gels. C-S-H gels filled the gel pores and transition pores in the cement skeleton and formed a dense, high thermal conductivity network, which shortens the heat transfer path and thus greatly improves the thermal conductivity of cement. In summary, this study has successfully developed a MEG geothermal cement with independent intellectual property rights that provides reliable technical support for the efficient development of geothermal resources and has important engineering application value.
研究领域:
能源工程
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材料科学
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石油工程
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热科学
✓ 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）