Processes
·
2024
·Vol. 12
·期 12
·2685
·
IF 2.8
Jian Zhu,Fei Wang,Shicheng Zhang,Xinfang Ma
Spontaneous imbibition (SI) effectively enhances oil recovery in shale reservoirs, significantly changing well shut-in and flowback design. This study conducted SI and displacement experiments to simulate the well shut-in and flowback stages so that the mechanism of imbibition and displacement between crude oil and fracture fluid can be discussed. In addition, the relative contribution to oil recovery of different types of pores in various stages and the effect of wettability were determined with low-field nuclear magnetic resonance (LF-NMR) via each sample’s T2transverse relaxation time at each time. The experimental results show that shale has multiscale pore structure characteristics combined with micropores, small mesopores, and mesopores. During the SI process, crude oil is displaced from micropores by fracture fluid at first, and then a large amount of oil production comes from small mesopores. Oil recovery of water-wet core samples is approximately 40.7%. Oil recovery of oil-wet core samples is about 26%. The wettability significantly affects the imbibition and displacement oil recovery of samples. For the process of SI, oil recovered from small mesopores takes the lead in the complete sample recovery. For the displacement process, oil recovered from small mesopores and mesopores take the lead in the complete sample recovery. After displacement, only 12% of fracture fluid flooded from the samples. This research, demonstrating the imbibition and displacement characteristics of terrestrial shale and several relevant affecting factors, contributes to understanding the fracturing fluid retention mechanism in shale reservoirs and provides crucial theoretical foundations for the development of shale oil reservoirs.
研究领域:
石油工程
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2025
·
IF 9.4
Da Cui,Peng Zhang,Shuang Wu,Hon Man Luk,Yixi Wu,Bin Liu,Shuo Pan,Jingru Bai,Qing Wang,Xuehua Zhang
Oil shale has garnered significant attention as a supplementary energy source to traditional fossil fuels. In this study, we investigated the catalytic hydrothermal liquefaction (HTL) of shale oil sludge using three catalysts (Fe, Na 2 CO 3 , Ni/Al 2 O 3 ) and three combinations in pairs. The hydrothermal oil (HTO) yield, energy recovery (ER), and conversion rate (CR) of organic matters were comprehensively analyzed under six catalyst conditions. Both Fe + Na 2 CO 3 and Fe + Ni/Al 2 O 3 paired catalyst combinations achieved similar HTO yields of 28.43 % and 28.13 % along with ER values of 56.19 % and 57.94 % respectively. Moreover, these two groups achieved remarkably high CR values of 81.88 % and 81.02 %, respectively. The HTO from the Fe + Ni/Al 2 O 3 combination has the highest H/C ratio and the lowest O/C ratio at 1.682 and 0.032, respectively. Elemental composition, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS) analyses of HTO were conducted in this study. The HTO produced by using Fe + Ni/Al 2 O 3 exhibited the most ideal distillation distribution, with fractions below diesel accounting for up to 96.94 %. Based on the catalytic functions of Fe, Ni, and Al 2 O 3 , six potential synergistic mechanisms of Fe + Ni/Al 2 O 3 were summarized. These mechanisms highlighted Fe + Ni/Al 2 O 3 's roles in promoting compound conversion pathways in HTO, ultimately revealing the synergistic catalytic mechanism.
研究领域:
能源化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Wei-Wei Yan,Xian-Yong Wei,Jun Li,Meng-Xiao Wang,Hong-Cun Bai,Zhi-Min Zong
Several liquid deep eutectic solvents (DESs) at room temperature were screened and used to extract phenols from an acetonitrile-extractable portion (ANEP) of the oil from oil shale pyrolysis. Among choline chloride (CC)/ethylene glycol (EG) with lowest viscosity and neutral oil entrainment (molar ratio = 1:3) was selected as an optimal DES for isolating phenols from ANEP. As a result, the CC/EG-extractable portion contains 56.7% of oxygen-containing aromatics, among which phenols account for 75.1% by magnetically stirring the isometric mass mixture of ANEP and the CC/EG at room temperature and 500 rpm for 0.5 h. Intermolecular interaction energy and type between different DESs and solutes were calculated by molecular dynamics simulation, independent gradient model analysis, energy decomposition analysis based on the force field, and electrostatic potential analysis to uncover the mechanism for the priority separation of phenols. The result shows that the DES that contains polar HBD with lower viscosity and carbon number and asymmetric HBA with shorter alkyl chains, e.g., CC/EG, could strongly interact with phenols by the strong hydrogen bond, X-H···π and/or cation/anion···π compared to other aromatics.
研究领域:
化学工程
·
计算化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Chemical Engineering and Processing-Process Intensification
·
2023
·
IF 4.3
Kai Guo,Ling Du,Yuling Lü,Limin He,Xiaoming Luo,Yin Bai
Shale oil is highly mineralized by salt ions, which makes it difficult to demulsify and dehydrate. The synergistic electromagnetic field (EMSF) is a more efficient method than AC electric field (ACEF) to enhance Shale oil dehydration. However, the critical coalescence conditions and transformation mechanism of droplets dispersed with electrolyte ions in EMSF still lack research. Herein, a series of Na 2 CO 3 -dispersed droplets with different ionic strengths were prepared, and the critical coalescence electric intensity ( E c ) of the droplets under ACEF and EMSF were compared. Micro high-speed experiments revealed that E c of droplets under EMSF is higher. Under the action of both EMSF and ACEF, E c decreases with the increase of ionic strength I s . An ion enrichment theory is proposed to explain the relationship between ion strength and potential energy. This study provides technical guidance for the performance regulation of EMSF-based equipment to enhance oil-water separation, the allowable optimal voltage should be higher than that of the electrostatic coalescer, and the adjustment range is 3.81 %–5.88 %.
研究领域:
石油工程
·
电化学
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Hongtao Fu,Kaoping Song,Erlong Yang,Lihao Liang,Yu Zhao,Zhehui Jin
Shale oil is an unconventional energy resource, and its efficient development is a key focus of current energy research. China’s continental shale resources are abundant, with high clay content and poor physical properties. The development of shale oil reservoirs after horizontal well fracturing remains suboptimal, requiring further recovery enhancement. Surfactant imbibition oil recovery technology is recognized as one of the effective methods for enhancing oil recovery in unconventional reservoirs. This study proposes a novel experimental apparatus and method for dynamic imbibition, and also develops a three-dimensional (3D) micro pore-fracture dynamic imbibition model. Furthermore, surfactant selection criteria based on wettability and interfacial tension are established. The results show that Cetyltrimethylammonium bromide (CTAB) forms ion pairs on the surface of shale pores, rapidly removing the oil film covering the shale surface. This induces a wettability reversal, reducing the water-phase contact angle from 132° to 55.1°. The use of the CTAB surfactant solution resulted in an 11.5 percentage points improvement in final imbibition efficiency. After CTAB surfactant solution detaches oil droplets from the shale surface, more of the water phase comes into contact with the clay minerals and micro-damage structures in the shale. Hydration induces new micro-damage in the shale, which accumulate and evolve into micro-fractures, creating flow channels for shale oil transport. Another key mechanism for enhancing the dynamic imbibition efficiency of continental shale oil is to modify the shale surface wettability while strategically adjusting interfacial tension. The selection criteria for surfactants used in shale oil dynamic imbibition should require not only wettability alteration capability but also an appropriate interfacial tension ranging from 2 to 10 mN/m. This balances the promoting effect of capillary forces with the suppressing effect of the Jamin effect, thereby facilitating the movement of oil droplets within deformed pores. Significant variations in average pressure within the pores enhance micro dynamic imbibition efficiency in shale. In the practical development of shale oil reservoirs, providing effective short-cycle energy replenishment and altering the average pressure within shale pores are crucial for guiding the enhancement of recovery in continental shale oil reservoirs.
研究领域:
石油工程
·
非常规能源
·
储层物理
·
界面科学
·
提高采收率技术
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2022
·Vol. 15
·期 15
·5599
·
IF 3.252
Siyuan Chen,Fanghui Liu,Yang Zhou,Xiuping Lan,Shouzhen Li,Lulu Wang,Quan Xu,Yeqing Li,Yan Jin
Proppant is an essential material in hydraulic fracturing, and it can support artificial fractures for a long time. However, few people have applied proppant and conductive materials in the in-situ modification of shale oil. Here, we developed a graphene and resin coated (GRC) proppant with electrically conductive properties. The electrical conductivity of the GRC proppant improved by four orders of magnitude. The GRC proppant has a 54.58% improvement in suspension and 22.75% increase in settlement time at 0.25 wt% concentration compared with uncoated proppant. The GRC proppant’s adhesion reached 68.34 nN under 1 μN load force, increasing by 63.13% compared to uncoated proppant. This new electrically conductive proppant can be used as a conductive carrier to improve the efficiency of electric heating in in-situ modification technology of shale oil.Keywords:shale oil;proppants;electrical conductivity;in-situ modification
研究领域:
材料科学
·
石油工程
·
化学工程
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2025
·
IF 5.3
Zixuan Wang,Mingwei Gao,Lianbao Yuan,Na Zhao,Liangfei Xiao,Hao Zheng,Yizheng Zhang,Yiming Zhang,Caili Dai
Shale oil development faces challenges such as rapid production decline and high-cost formation damage caused by refracturing. To address these issues, this study proposes an active silica-based nanofluid with a total concentration of 0.12 wt % (0.045 wt % nanoparticles and 0.075 wt % AES surfactant). Dynamic light scattering (DLS) analysis demonstrates that the nanofluid exhibits excellent stability under high-temperature and high-salinity conditions (90 °C, salinity of 1.0 × 105 mg/L), maintaining an average hydrodynamic diameter of approximately 22 nm, which is significantly smaller than that of the unmodified system (30 nm). Interfacial tension (IFT) measurements revealed a stable IFT of 0.358 mN/m at a concentration of 0.3 wt %, while dynamic contact angle tests confirmed its strong wettability alteration capability. Spontaneous imbibition experiments revealed enhanced oil recovery, with increases of 23.8 and 10.62% compared to simulated formation water (SF water) and AES alone, respectively. Additionally, results indicated that higher core permeability facilitated easier oil–water extraction, while oil saturation primarily influenced oil–water displacement through the starting pressure gradient. A multiscale pore classification model was established by integrating nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and nitrogen adsorption analysis, enabling the quantification of oil contributions from different pore size ranges: micropores (<0.07 μm) contributed 50.94%, macropores (>3.67 μm) 28.92%, and mesopores (0.07–3.67 μm) 20.15%. These results demonstrate its crucial role in overall oil recovery during shale imbibition. Finally, the mechanism behind enhanced recovery was elucidated through synergistic wettability alteration and capillary displacement equations. This work presents a cost-effective nanofluid formulation and a multiscale pore analysis methodology, providing practical approaches and theoretical insights for enhancing shale oil recovery.
研究领域:
石油工程
·
油气田开发
·
纳米技术应用
·
多孔介质输运
·
界面科学
✓ 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）