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Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation
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作者 ZOU Yushi LI Yanchao +3 位作者 YANG Can ZHANG Shicheng MA Xinfang ZOU Longqing 《Petroleum Exploration and Development》 SCIE 2024年第3期715-726,共12页
This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion w... This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures. 展开更多
关键词 shale temporary plugging and diversion fracturing multi-cluster sand jetting perforation distribution of temporary plugging agent fracture propagation law
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A novel responsive stabilizing Janus nanosilica as a nanoplugging agent in water-based drilling fluids for exploiting hostile shale environments
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作者 Alain Pierre Tchameni Lv-Yan Zhuo +5 位作者 Lesly Dasilva Wandji Djouonkep Robert Dery Nagre Lu-Xin Chen Lin Zhao Chao Ma Bin-Qiang Xie 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1190-1210,共21页
Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not bee... Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments. 展开更多
关键词 Janus nanosilica Thermo-responsive copolymer Anti-polyelectrolyte effect Shale stabilizer Inhibition plugging Drilling fluid
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A Gel-Based Solidification Technology for Large Fracture Plugging
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作者 Kunjian Wang Ruibin He +3 位作者 Qianhua Liao Kun Xu Wen Wang Kan Chen 《Fluid Dynamics & Materials Processing》 EI 2024年第3期563-578,共16页
Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often unde... Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often undergo contaminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based composite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high compressive strength and resistance to the aforementioned contamination, therebyleading to notable increase in plugging success rate. The compressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the compressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be controlled to be more than3 h, thereby providing a safe construction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All considered performance indicators of the oil-based gel confirm itssuitability as a plugging agent for fault fractures. 展开更多
关键词 Drilling loss fault fracture oil-based gel compressive strength gel plugging
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Dynamic plugging regulating strategy of pipeline robot based on reinforcement learning
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作者 Xing-Yuan Miao Hong Zhao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期597-608,共12页
Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the p... Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the pipeline and PIPR. In this paper, we propose a dynamic regulating strategy to reduce the plugging-induced vibration by regulating the spoiler angle and plugging velocity. Firstly, the dynamic plugging simulation and experiment are performed to study the flow field changes during dynamic plugging. And the pressure difference is proposed to evaluate the degree of flow field vibration. Secondly, the mathematical models of pressure difference with plugging states and spoiler angles are established based on the extreme learning machine (ELM) optimized by improved sparrow search algorithm (ISSA). Finally, a modified Q-learning algorithm based on simulated annealing is applied to determine the optimal strategy for the spoiler angle and plugging velocity in real time. The results show that the proposed method can reduce the plugging-induced vibration by 19.9% and 32.7% on average, compared with single-regulating methods. This study can effectively ensure the stability of the plugging process. 展开更多
关键词 Pipeline isolation plugging robot plugging-induced vibration Dynamic regulating strategy Extreme learning machine Improved sparrow search algorithm Modified Q-learning algorithm
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Plugging behaviors of temporary plugging particles in hydraulic fractures
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作者 GUO Jianchun ZHAN Li +5 位作者 LU Qianli QI Tianjun LIU Yuxuan WANG Xin CHEN Chi GOU Xinghao 《Petroleum Exploration and Development》 SCIE 2023年第2期464-472,共9页
Using the visualized experimental device of temporary plugging in hydraulic fractures, the plugging behaviors of temporary plugging particles with different sizes and concentrations in hydraulic fractures were experim... Using the visualized experimental device of temporary plugging in hydraulic fractures, the plugging behaviors of temporary plugging particles with different sizes and concentrations in hydraulic fractures were experimentally analyzed under the conditions of different carrier fluid displacements and viscosities. The results show that the greater the carrier fluid viscosity and displacement, the more difficult it is to form a plugging layer, and that the larger the size and concentration of the temporary plugging particle, the less difficult it is to form a plugging layer. When the ratio of particle size to fracture width is 0.45, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle and the viscosity of the carrier fluid, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 20 kg/m^(3)or the viscosity of the carrier fluid is greater than 3 mPa·s. When the ratio of particle size to fracture width is 0.60, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 10 kg/m^(3). When the ratio of particle size to fracture width is 0.75, the formation of the plugging layer is basically not affected by other parameters, and a stable plugging layer can form within the experimental conditions. The formation process of plugging layer includes two stages and four modes. The main controlling factors affecting the formation mode are the ratio of particle size to fracture width, carrier fluid displacement and carrier fluid viscosity. 展开更多
关键词 hydraulic fracture temporary plugging and diversion temporary plugging particle plugging characteristics construction parameters combination
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Numerical Analysis of Dynamical Effects Associated with a Plugging String in a Horizontal Well
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作者 Guangsheng Liu Qingming Gan +4 位作者 WenWu Haitao Yang Yiming Lv Wenhao Cui Wei Lin 《Fluid Dynamics & Materials Processing》 EI 2023年第5期1203-1214,共12页
The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has b... The finite element method has been applied to simulate the dynamics of a water plugging string in a complex horizontal well of a low-permeability oilfield.The force associated with the pipe string and the packer has been determined under the sucking action of the oil well pump.Such analysis has been conducted for a real drilling well,taking into account the process of lifting,lowering,unblocking and water plugging.Comparison between field measured data and simulation data indicates that the model is reliable and accurate.The packer creep effect under different pressure differences has also been investigated in the framework of the same model. 展开更多
关键词 Water plugging string horizontal well creep effect mechanical water plugging
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Complex fracture propagation model and plugging timing optimization for temporary plugging fracturing in naturally fractured shale
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作者 TANG Xuanhe ZHU Haiyan +1 位作者 CHE Mingguang WANG Yonghui 《Petroleum Exploration and Development》 2023年第1期152-165,共14页
In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution a... In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution among multi-clusters are considered as well.DFN-FEM(discrete fracture network combined with finite element method)was developed to simulate the multi-cluster complex fractures propagation within temporary plugging fracturing(TPF).Numerical results are matched with field injection and micro-seismic monitoring data.Based on geomechanical characteristics of Weiyuan deep shale gas reservoir in Sichuan Basin,SW China,a multi-cluster complex fractures propagation model is built for TPF.To study complex fractures propagation and the permeability-enhanced region evolution,intersecting and competition mechanisms between the fractures before and after TPF treatment are revealed.Simulation results show that:fracture from middle cluster is restricted by the fractures from side-clusters,and side-clusters plugging is benefit for multi fractures propagation in uniformity;optimized TPF timing should be delayed within a higher density or strike of natural fractures;Within a reservoir-featured natural fractures distribution,optimized TPF timing for most clustered method is 2/3 of total fluid injection time as the optimal plugging time under different clustering modes. 展开更多
关键词 shale gas naturally fractured shale temporary plugging fracturing fracture propagation plugging timing discrete fracture network finite element method
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Experimental study of the temporary plugging capability of diverters to block hydraulic fractures in high-temperature geothermal reservoirs
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作者 Dao-Bing Wang Hao Qin +3 位作者 Yong-Liang Wang Jian-Qiao Hu Dong-Liang Sun Bo Yu 《Petroleum Science》 SCIE EI CAS CSCD 2023年第6期3687-3699,共13页
The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry... The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry rock.At present,how temporary plugging agents plug artificial fractures under high temperature remains unclear.In this paper,by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature,we clarified the effects of high temperature,injection rate,and fracture width on the pressure response and plugging efficiency of the fracture.The results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages:the initial stage of temporary plugging,the bridging stage of the particles,the plugging formation stage,and the high-pressure dense plugging stage.As the temperature increases,the distribution distance of the temporary plugging agent,the number of pressure fluctuations,and the time required for crack plugging increases.Particularly,when the temperature increases by 100℃,the complete plugging time increases by 90.7%. 展开更多
关键词 High temperature Diverter material Fracture plugging capability Hydraulic fracturing Experimental study
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Optimization of the Plugging Agent Dosage for High Temperature Salt Profile Control in Heavy Oil Reservoirs
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作者 Jiayu Ruan Mingjing Lu +5 位作者 Wei Zhang Yuxi Zhang Yuhui Zhou Jie Gong Fan Wang Yuanxiao Guan 《Fluid Dynamics & Materials Processing》 EI 2023年第2期421-436,共16页
After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of th... After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of the oil displacement.Previous studies have shown that the salting-out plugging method can effectively block these channels in high-temperature reservoirs,improve the suction profile,and increase oil production.In the present study,the optimal dosage of the plugging agent is determined taking into account connection transmissibility and inter-well volumes.Together with the connectivity model,a water flooding simulation model is introduced.Moreover,a non-gradient stochastic disturbance algorithm is used to obtain the optimal plugging agent dosage,which provides the basis for the high-temperature salting-out plugging agent adjustment in the field. 展开更多
关键词 Heavy oil salting out profile control high temperature plugging agent dosage optimization numerical simulation connectivity model
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Fatigue Life Analysis of Coiled Tubing in Deep Well Jet Plugging Removal
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作者 Ju Liu Qiao Wang +3 位作者 Wei Zhang Zhihong Zhou Wenzhong Hu Yan Wang 《World Journal of Engineering and Technology》 2023年第1期48-54,共7页
The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order... The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs. 展开更多
关键词 Coiled Tubing plug Removal by Jetting Fatigue Life Plough Surface Damage RESONANCE
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Influence of Incomplete Soil Plugs on Bearing Capacities of Bucket Foundations in Clay
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作者 LI Hui-shan LIU Run +1 位作者 YANG Xu LIAN Ji-jian 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期144-155,共12页
Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be eval... Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be evaluated.In this paper,the contact ratio(the ratio of the top diameter of the soil plug to the diameter of the bucket)and the soil plug ratio(the ratio of the soil heave height to the skirt height)are defined to describe the shape and size of the incomplete soil plug.Then,finite element models are established to investigate the bearing capacities of bucket foundations with incomplete soil plugs and the influences of the contact ratios,and the soil plug ratios on the bearing capacities are analyzed.The results show that the vertical bearing capacity of bucket foundations in homogeneous soil continuously improves with the increase of the contact ratio.However,in normally consolidated soil,the vertical bearing capacity barely changes when the contact ratio is smaller than 0.75,while the bearing capacity suddenly increases when the contact ratio increases to 1 due to the change of failure mode.The contact ratio hardly affects the horizontal bearing capacity of bucket foundations.Moreover,the moment bearing capacity improves with the increase of the contact ratio for small aspect ratios,but hardly varies with increasing contact ratio for aspect ratios larger than 0.5.Consequently,the reduction coefficient method is proposed based on this analysis to calculate the bearing capacities of bucket foundations considering the influence of incomplete soil plugs.The comparison results show that the proposed reduction coefficient method can be used to evaluate the influences of incomplete soil plug on the bearing capacities of bucket foundations. 展开更多
关键词 bucket foundation incomplete soil plug uniaxial bearing capacity contact ratio soil plug ratio
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Study on Chrome-free Purging Plugs for Steel Ladles
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作者 Yunpeng ZHOU Wang FENG +2 位作者 Shankha CHATTERJEE Andus BUHR Sebastian KLAUS 《China's Refractories》 CAS 2024年第2期41-47,共7页
Purging plug refractories in China typically contain around 3 mass% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. A... Purging plug refractories in China typically contain around 3 mass% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. Alternatives to chromium oxide containing refractories have gained interest due to health concerns related to the formation of soluble chromium compounds over long storage periods of refractory wastes. Super-ground reactive alumina can replace chromium oxide in purging plug refractories and this paper discussed the new reactive alumina E-SY 88 in comparison to chromium oxide in a typical purging plug castable. The mixing behaviour, wet castable properties, as well as cured, dried, and fired properties at different temperatures up to 1 600 ℃ were compared. In addition, the hot modulus of rupture, creep behaviour, thermal shock resistance and slag corrosion resistance were tested. The microstructure after slag corrosion was investigated by SEM. The results prove that E-SY 88 is an economically viable technical alternative to chromium oxide in purging plug refractories. 展开更多
关键词 purging plug alumina-spinel castable WORKABILITY chromium-free thermal shock resistance
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Combination of Plugging and Acidization Improves Injection Profile
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作者 赵普春 赵化廷 杨新明 《Petroleum Science》 SCIE CAS CSCD 2004年第4期77-87,共11页
Plugging agent treatment and acid stimulation have completely different mechanisms for improving injection profiles. In this paper, a hybrid procedure is introduced to reduce the damage of the plugging agent to low a... Plugging agent treatment and acid stimulation have completely different mechanisms for improving injection profiles. In this paper, a hybrid procedure is introduced to reduce the damage of the plugging agent to low and medium permeability zones and the penetration radius of acid into high permeability zones. The procedure is: First inject plugging agent to block high permeability zones, and then inject acid to remove plugging agent damage from the low and medium permeability zones and stimulate them. To perform this procedure successfully, three kinds of plugging agents, namely strong strength plugging agent for the wells with fractures or high permeability streaks, weak gel for those with thick layer in which serious heterogeneity exists, temporary plugging agent for those in which the absorption ability of high permeability zones needs maintaining, were screened out for use in different reservoirs. Several acid systems were evaluated to be compatible with the three kinds of plugging agents. The objectives of this paper are:(1)To show the screen results about the compatible plugging agent and acid; 2 To show how to optimize the operation process;(3)To tell some experience gained ( ) from the oilfield applications of this technique. From Jan. 2001 to Dec. 2002, 46 operations using this procedure were carried out in Weicheng and Mazhai Oilfields of SINOPEC. Results show that the average benefit/cost ratio is over 3.5. Experience acquired from these applications was summarized in the paper. 展开更多
关键词 Profile Control plugging and acid inject profile IMPROVE TECHNIQUE
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Experimental investigation of enhancement of carbon dioxide foam stability, pore plugging, and oil recovery in the presence of silica nanoparticles 被引量:5
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作者 Abdul Rahim Risal Muhammad A.Manan +3 位作者 Nurudeen Yekeen Nur Bashirah Azli Ali Mohamed Samin Xin Kun Tan 《Petroleum Science》 SCIE CAS CSCD 2019年第2期344-356,共13页
The influence of surface-modified silica(SiO_2) nanoparticles on the stability and pore plugging properties of foams in porous media was investigated in this study. The pore plugging ability of foams was estimated fro... The influence of surface-modified silica(SiO_2) nanoparticles on the stability and pore plugging properties of foams in porous media was investigated in this study. The pore plugging ability of foams was estimated from the pressure drop induced during foam propagation in porous media. The results clearly showed that the modified Si02 nanoparticlestabilized foam exhibited high stability, and the differential pressure increased in porous media by as much as three times.The addition of SiO_2 nanoparticles to the foaming dispersions further mitigated the adverse effect of oil toward the foam pore plugging ability. Consequently, the oil recovery increased in the presence of nanoparticles by approximately 15%during the enhanced oil recovery experiment. The study suggested that the addition of surface-modified silica nanoparticles to the surfactant solution could considerably improve the conventional foam stability and pore plugging performance in porous media. 展开更多
关键词 Foam PORE plugging Surface-modified NANOPARTICLE Enhanced OIL RECOVERY
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Analysis and Online Diagnosis on Plugging Fault of Servo Valve in Electro-hydraulic Regulating System of Steam Turbine 被引量:6
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作者 WANG Xuanyin LI Xiaoxiao LI Fushang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第2期233-237,共5页
Through the study on the output signals of the electro-hydraulic regulating system in the thermal power plant, a novel method for online diagnosis of the plugging fault in the servo valve is presented. With the use of... Through the study on the output signals of the electro-hydraulic regulating system in the thermal power plant, a novel method for online diagnosis of the plugging fault in the servo valve is presented. With the use of the AMESIM software, the changes of the piston displacement, the oil pressure, the magnitude attenuation and the phase lag of the system under different plugging states are studied after simulation. Besides, the influences of the symmetrical and unsymmetrical plugging on the system are also compared and the characteristic table is given. The duo-neural network is put forward to achieve an online diagnosis on the plugging fault of the servo valve. The first level of network helps to make the qualitative diagnosis of the plugging position while the second level is for the quantitative diagnosis of the degree of the plugged position. The research results show that plugging at different positions exerts different influences on the performance of the system. The unsymmetrical plugging mainly affects the regulation time while the symmetrical plugging leads to great changes in the magnitude attenuation and the phase lag. 展开更多
关键词 steam turbine regulating system plugging diagnosis AMESIM software
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Thermo-sensitive polymer nanospheres as a smart plugging agent for shale gas drilling operations 被引量:10
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作者 Wei-Ji Wang Zheng-Song Qiu +2 位作者 Han-Yi Zhong Wei-An Huang Wen-Hao Dai 《Petroleum Science》 SCIE CAS CSCD 2017年第1期116-125,共10页
Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radica... Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive mono- mer N-isopropylacrylamide (NIPAm) and hydrophilic monomer acrylic acid (AA) onto the surface of P(MMA- St) nanospheres at 80 ℃, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures (LCST), were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD- SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability 展开更多
关键词 Nanoparticle plugging agent Polymermicrospheres Thermo-sensitive polymer Wellborestability - Shale gas - Drilling fluid
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Effect of the distributor plugging ways on fluidization quality and particle stratification in air dense medium fluidized bed 被引量:8
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作者 Zhonglin Gao Xuesen Chai +3 位作者 Enhui Zhou Ying Jia Chenlong Duan Ligang Tang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2020年第6期883-888,共6页
Gas-solid fluidized bed separation is a highly efficient and clean technique for coal separation,and can effectively remove ash and sulfur contained gangue minerals from coal.However,the fine coal plugging distributor... Gas-solid fluidized bed separation is a highly efficient and clean technique for coal separation,and can effectively remove ash and sulfur contained gangue minerals from coal.However,the fine coal plugging distributor often leads to uneven fluidization and affects the separation effect.In this paper,different plugging ways were designed to study their effects on the fluidization characteristics and particle mixing.It was found that when the plugging phenomenon occurs,the minimum fluidization velocity of the fluidized bed gradually decreases as the plugging area enlarges.The difference between the top and the bottom of the bed minimum fluidization velocity increases accordingly,and a“stagnation phenomenon”occurs in the bed.The standard deviation of pressure fluctuations at the top of the bed is smaller than that at the bottom of the bed,which is the opposite of normal conditions.As the area of the plugging increases,the dead zone on the side wall of the fluidized bed significantly increases.The size of the dead zone is rapid reducing at the initial stage.It was noticed that the stratification of the low-density products is particularly affected by plugging,whereas the stratification of high-density products is not obviously influenced by certain conditions. 展开更多
关键词 Dry separation DISTRIBUTOR plugging Particle mixing
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Effects of fluid flow rate and viscosity on gravel-pack plugging and the optimization of sand-control wells production 被引量:2
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作者 DONG Changyin ZHOU Yugang +4 位作者 CHEN Qiang ZHU Chunming LI Yanlong LI Xiaobo LIU Yabin 《Petroleum Exploration and Development》 2019年第6期1251-1259,共9页
Series of experiments were performed to simulate the invasion of formation sand into and the plugging process of gravel-pack at different viscosities and flowing rates of fluid.Two types of formation sands with the me... Series of experiments were performed to simulate the invasion of formation sand into and the plugging process of gravel-pack at different viscosities and flowing rates of fluid.Two types of formation sands with the medium size of 0.10 mm and 0.16 mm and the quartz sand and ceramsite of 0.6-1.2 mm were used in the experiments.A new viscosity-velocity index(the product of fluid viscosity and velocity)was put forward to characterize the influencing mechanism and law of physical property and flow condition of formation fluid on gravel-pack plugging,and a new method to optimize the production rate of wells controlling sand production with gravel-packing was proposed.The results show that the permeability of formation sand invaded zone and final permeability of plugged gravel-pack have negative correlations with viscosity and flow velocity of fluid,the higher the flow velocity and viscosity,the lower the permeability of formation sand invaded zone and final permeability of plugged gravel-pack will be.The flow velocity and viscosity of fluid are key factors affecting plugging degree of the gravel zone.The viscosity-velocity index(v-v index)can reflect the flow characteristics of fluid very well and make it easier to analyze the plugging mechanism of gravel zone.For different combinations of fluid viscosity and flow velocity,if the v-v index is the same or close,their impact on the final gravel permeability would be the same or close.With the increase of the v-v index,the permeability of plugged gravel zone decreases first,then the reduction rate slows down till the permeability stabilizes.By optimizing production and increasing production step by step,the optimal working scheme for sand-control well can reduce the damage to gravel-pack zone permeability caused by sand-carrying fluid effectively,and increase well productivity and extend the sand control life. 展开更多
关键词 gravel-pack sand RETENTION experiment plugging law viscosity-velocity index working scheme OPTIMIZATION method plugging simulation
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LEAKAGE-PLUGGING WHILE DRILLING AND PLUGGING AGENTS 被引量:1
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作者 Peng Zhenbin Zhang Xuzhi Dai Qianwei(Department of Geology, Central South University ofTechnology, Changsha 410083, China) 《Journal of Central South University》 SCIE EI CAS 1996年第1期29-32,共4页
This paper describes a series of plugging agents which have been developed these years by the authors. The features of these agents can bestated as: (1) Stopping losses without stopping drilling; (2) High ratio of suc... This paper describes a series of plugging agents which have been developed these years by the authors. The features of these agents can bestated as: (1) Stopping losses without stopping drilling; (2) High ratio of success; (3) Improving fluids properties; (4) Suiting to many types of losses, even large cracks and caves; (5) Perfect efficiency in different conditions of pollution such as calcium, salt pollution and high temperature; (6) Sufficient resources of raw materials, nopoison, noharm, no pollution to the environment; (7) Convenience in use; (8) Lower cost. The properties, mechanisms and applications of these agents are also described in this paper. 展开更多
关键词 Leakageplugging DRILLING plugging AGENTS
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A bull-heading water control technique of thermo-sensitive temporary plugging agent 被引量:3
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作者 LIU Pingde WEI Falin +3 位作者 ZHANG Song ZHU Xiuyu WANG Longfei XIONG Chunming 《Petroleum Exploration and Development》 2018年第3期536-543,共8页
Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solu... Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production. 展开更多
关键词 bull-heading water control TECHNIQUE THERMO-SENSITIVE TEMPORARY plugging agent secondary TEMPORARY plugging TECHNIQUE thermal degradation property RESERVOIR protection
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