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Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study
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作者 Chong Lin Qi-Cong Xu +4 位作者 Lie-Xiang Han Gao Li Hai He Hong-Ling Zhou Ji-Ping She 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期567-581,共15页
Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)formations.Lost circulation material(LCM)is a regular preventive and remedial measure for lost circulatio... Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)formations.Lost circulation material(LCM)is a regular preventive and remedial measure for lost circulation.However,conventional LCMs seem ineffective in high-temperature formations.This may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature conditions.To understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in fractures.We summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling fluid.We conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing temperatures.The results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid viscosity.Smaller,softer,and less frictional LCM particles have lower bridging probability and slower bridging initiation.Smaller particles tend to form dual-particle bridges rather than single-particle bridges.These result in a deeper,tighter,but unstable sealing zone.Reduced drilling fluid viscosity leads to faster and shallower sealing zones. 展开更多
关键词 Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing
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Preparation and properties of magnesium oxysulfate cement and its application as lost circulation materials 被引量:2
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作者 Kai-Xiao Cui Guan-Cheng Jiang +2 位作者 Li-Li Yang Zheng-Qiang Deng Lei Zhou 《Petroleum Science》 SCIE CAS CSCD 2021年第5期1492-1506,共15页
Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less... Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less hygroscopic nature and less damaging to steel casings compared with magnesium oxychloride(MOC)cement.The present study developed MOS cement as a fast setting,high strength and acid-soluble lost circulation material to reduce the problem of losses.As suggested in this study,a higher strength of MOS cement at 70℃could be achieved by elevating M_(g)O/MgSO_(4)·7 H_(2)O molar ratio or downregulating H_(2)O/MgSO_(4)·7 H_(2)O molar ratio.Boric acid and borax could act as effective retarders.Plugging slurry based on MOS cement could effectively block the simulated porous loss zones exhibiting a diameter from 1.24 mm to 1.55 mm,as well as the fractured loss zones with a width from 2 mm to 5 mm and bearing a pressure difference up to 8 MPa.Permeability recovery test demonstrated that it facilitated future oil and gas production.The successful field application in the Junggar Basin,Xinjiang,China verified the significant plugging effect of MOS cement for severe loss problems. 展开更多
关键词 Magnesium oxysulfate cement Lost circulation material Severe loss Acid soluble plug Formation damage
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Circulation Technology and Model of Agroforestry and Animal Husbandry
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作者 何成芳 闫晓明 +2 位作者 朱鸿杰 陈志豪 谭外球 《Agricultural Science & Technology》 CAS 2016年第6期1498-1505,共8页
On basis of analysis on agroforestry-animal husbandry ecosystem characters, the research explored nutrient flow model of material cycle and carbon cycle and agroforestry-animal husbandry mutualism model and supporting... On basis of analysis on agroforestry-animal husbandry ecosystem characters, the research explored nutrient flow model of material cycle and carbon cycle and agroforestry-animal husbandry mutualism model and supporting technology in Yangtze-Huaihe Region, taking Robinia pseudoacacia stand and rubber garden as an example. 展开更多
关键词 Eco-system between agriculture and animal husbandry circulation of material Carbon cycle Technology system
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Research progress and prospect of plugging technologies for fractured formation with severe lost circulation 被引量:7
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作者 SUN Jinsheng BAI Yingrui +6 位作者 CHENG Rongchao LYU Kaihe LIU Fan FENG Jie LEI Shaofei ZHANG Jie HAO Huijun 《Petroleum Exploration and Development》 CSCD 2021年第3期732-743,共12页
By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured f... By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured formations have been summarized. Meanwhile, based on the types of lost circulation materials, the advantages, disadvantages, and application effects of corresponding plugging technologies have been analyzed to sort out the key problems existing in the current lost circulation control technologies. On this basis, the development direction of plugging technology for severe loss have been pointed out. It is suggested that that the lost circulation control technology should combine different disciplines such as geology, engineering and materials to realize integration, intelligence and systematization in the future. Five research aspects should be focused on:(1) the study on mechanisms of drilling fluid lost circulation and its control to provide basis for scientific selection of lost circulation material formulas, control methods and processes;(2) the research and development of self-adaptive lost circulation materials to improve the matching relationship between lost control materials and fracture scales;(3) the research and development of lost circulation materials with strong retention and strong filling in three-dimensional fracture space, to enhance the retention and filling capacities of materials in fractures and improve the lost circulation control effect;(4) the research and development of lost circulation materials with high temperature tolerance, to ensure the long-term plugging effect of deep high-temperature formations;(5) the study on digital and intelligent lost circulation control technology, to promote the development of lost circulation control technology to digital and intelligent direction. 展开更多
关键词 severe lost circulation lost circulation control mechanism lost circulation materials lost circulation control technology drilling fluid lost circulation plugging technologies progress
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Study on an novel composite gel material solving serious lost circulations and pressurization sealing 被引量:1
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作者 YE Yan YAN Jie-nian +1 位作者 GUO Jian-hua XIE You-xin 《Journal of Energy and Power Engineering》 2007年第1期68-75,共8页
Lost circulations have presented great challenges to the petroleum industry, causing great expenditures of cash and time to fighting the problem. Probably the most problematic situations are the naturally fractured fo... Lost circulations have presented great challenges to the petroleum industry, causing great expenditures of cash and time to fighting the problem. Probably the most problematic situations are the naturally fractured formations where the operator may face total loss with no mud return in the annular. The voids or large fracture encountered in this case are often far too large to be plugged with conventional Lost Circulation Material. This paper will give a detailed introduction on a novel composite gel material usable to control severe losses and pressurization sealing. The plugging mechanics of this new composite gel material, which is different from conventional lost circulation materials, were elaborated as well. In addition, the properties of the new composite gel material such as thermostability, sealing strength and bearing resistance are characterized with specific experimental devices. The experimental results proved that the breakdown pressure of the new plugging reached more than 20MPa, and the maximum degraded temperature can be exceed 130℃. The field application at 4 wells in Puguang gas field, SINOPEC, demonstrated that the new composite gel material solved the serious loss in Ordovician carbonate fractured formation successfully and guaranteed the following completion cement operation smoothly. The composite gel sealing slurries, which was easily prepared on site, gives remarkable properties regarding pumping through drill pipes, adjustment of setting time and excellent sealing strength of the lost zone sealing, additionally, the whole pressurization sealing process was complicated within only ten hours. The on-site results show that the plugging ratio of the new composite gel was reached 100%, and the success rate of sealing operation kept above 80%.Thus the new LCM can guarantee safe drilling jobs and save operation cost more effectively. 展开更多
关键词 Lost circulation Material (LCM) composite gel sealing strength breakdown pressure pressurized sealing Puguang gas field
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Tracing technique of stable ^(15)N isotope: an application in study of mariculture
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作者 Hong Ashi Li Wenquan and Wang Mingliang(Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China)(Department of Oceanography, Xiamen University, Xiamen 361005, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1995年第1期39-45,共7页
Using Na15NO3 and 15NH4Cl as tracer, we studied the transfer of 15N along the food chain composed oforganisms such as Platymonas subcordiformis, Artemia salina, Penaeus penicillatus and Liza carinatus . The abundancea... Using Na15NO3 and 15NH4Cl as tracer, we studied the transfer of 15N along the food chain composed oforganisms such as Platymonas subcordiformis, Artemia salina, Penaeus penicillatus and Liza carinatus . The abundanceand atomic percentage of 15N in each organism, as well as the transfer of 15N among different biological phases weremeasured. Results show that, in the nutrient transfer from low level to high level along the md chain in the mediaof 15NH4Cl, the transfer rate of Artemia salina→Liza carinatus exceeded 3% and was higher than that in Na15NO3; the accumulation of 15N in the bodies of Liza carinatus with 15NH4Cl as media was also higher than that withNa 15NO3 as media. 展开更多
关键词 Stable isotopic tracing food chain material circulation mariculture ecology
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Performance evaluation of nanosilica derived from agro-waste as lost circulation agent in water-based mud
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作者 Augustine Agi Jeffrey O.Oseh +3 位作者 Afeez Gbadamosi Cheo Kiew Fung Radzuan Junin Mohd Zaidi Jaafar 《Petroleum Research》 EI 2023年第2期256-269,共14页
Seepage or loss of the mix-water from the drilling muds into the porous and permeable formations is a common problem during drilling operation.The drilling mud design requires a good knowledge of sealing integrity and... Seepage or loss of the mix-water from the drilling muds into the porous and permeable formations is a common problem during drilling operation.The drilling mud design requires a good knowledge of sealing integrity and all the factors influencing the mud to bridge through fractures or pore throat of exposed rocks.Loss circulation materials(LCMs)are commonly introduced into the drilling mud to prevent or minimize filtrate loss.This study investigates silica nanoparticle(SNP)derived from rice husk(RH)termed RH-SNP using the wet-milling method as an LCM inwater-based mud(WBM).The impact of the RH-SNP in the enhancement of rheology and filtrate loss control properties of WBM was studied.Subsequently,the sealing integrity of the RH-SNP in a 1 mm and 2 mm simulated fracture for 7 min was determined using a stainless-steel slotted filter disk.The performance of the developed RH-SNP was compared with the widely applied nutshell.The synthesized RH-SNP at amount of 2.0 wt% significantly enhanced the yield point and plastic viscosity of the WBM by 75% and 386%,respectively,and minimized the fluid loss of the WBM by 47% at 80°F.The enhancement is due to the particles ability to spread and interact efficiently with the WBM.With the use of 1 mm and 2 mm simulated fracture for 7 min,the mud loss volume of the base mud reduced by 50%,66.7%,86%,and 90%(for 1 mm)and 40%,65.7%,77.1%,and 80%(for 2 mm)with the inclusion of 0.5 wt%,1.0 wt%,1.5 wt%,and 2.0 wt% of RH-SNP,respectively.Overall,the results showed that RH-SNP enhanced the seal integrity of the drilling mud and was more resistant to deformation compared to the nutshell.The findings of this study can help for better understanding of the application of RH-SNP as a loss circulation agent owing to its superior ability to seal fractured formation compared with the often used nutshell. 展开更多
关键词 Rice husk silica nanoparticles Loss circulation material Fractured formation Water based-mud RHEOLOGY
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Experimental study on the controlling factors of frictional coefficient for lost circulation control and formation damage prevention in deep fractured tight reservoir
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作者 Chengyuan Xu Honglin Zhang +4 位作者 Mingming Zhu Yili Kang Xiaopeng Yan Jingyi Zhang Yingrui Bai 《Petroleum》 EI CSCD 2022年第3期352-362,共11页
Working fluids loss is a major contributor to low productivity during production process of fractured tight reservoirs.Lost circulation control effect directly related to the tribological behavior between fracture sur... Working fluids loss is a major contributor to low productivity during production process of fractured tight reservoirs.Lost circulation control effect directly related to the tribological behavior between fracture surface and lost circulation materials(LCMs).In this study,the friction coefficient(FC)was investigated using typical clastic rocks and LCMs by considering multiple effect factors divided into external condition and internal condition.The results show that normal load had a relatively high effect on sliding model.A positive correlation was observed between FC and asperities heights.FC decreased induced by particle size degradation of rigid LCMs.Elastic LCMs manifested higher FC compared with rigid LCMs.Under the lubrication condition by working fluid,FC of rigid LCMs was mainly controlled by their surface wettability.FC of organic LCMs is more sensitive to high temperature aging than inorganic LCMs.Fracture plugging experiments show that LCMs optimized based on the research results can effectively improve the efficiency and strength of fracture plugging. 展开更多
关键词 Fractured tight reservoirs Lost circulation control Friction coefficient Lost circulation materials
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