In this work,the factors affecting asphaltenes deposition in high-temperature and high-pressure wells were studied using backscattered light and PVT equipment customized to suit the well conditions.In an examination o...In this work,the factors affecting asphaltenes deposition in high-temperature and high-pressure wells were studied using backscattered light and PVT equipment customized to suit the well conditions.In an examination of the intensity of backscattered light,it was revealed that there exists a linear relationship between temperature and asphaltene precipitation within a specific temperature range.Within this range,a decrease in temperature tends to accelerate asphaltene precipitation.However,the impacts of pressure and gas-oil ratio are more pronounced.The pressure depletion induces the asphaltenes to precipitate out of the solution,followed by the formation of flocs below the bubble point.In addition,an increase in the gas-oil ratio causes a more severe asphaltene deposition,shifting the location of asphaltenes to deep well sections.展开更多
Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability...Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.展开更多
For safe and efficient development of the sour gas reservoirs of the Cambrian Longwangmiao Fm in the Anyue Gas Field,the Sichuan Basin,and reduction of safety barrier failures and annulus abnormal pressure which are c...For safe and efficient development of the sour gas reservoirs of the Cambrian Longwangmiao Fm in the Anyue Gas Field,the Sichuan Basin,and reduction of safety barrier failures and annulus abnormal pressure which are caused by erosion,corrosion,thread leakage and improper well completion operations,a series of studies and field tests were mainly carried out,including optimization of well completion modes,experimental evaluation and optimization of string materials,sealing performance evaluation of string threads,structural optimization design of downhole pipe strings and erosion resistance evaluation of pipe strings,after the technical difficulties related with the well completion in this reservoir were analyzed.And consequently,a set of complete well completion technologies suitable for HTHP(high temperature and high pressure)and highflowrate gas wells with acidic media was developed as follows.First,optimize well completion modes,pipe string materials and thread types.Second,prepare optimized string structures for different production allocation conditions.And third,formulate well completion process and quality control measures for vertical and inclined wells.Field application results show that the erosion of high-flowrate production on pipe strings and downhole tools and the effect of perforation on the sealing performance of production packers were reduced effectively,well completion quality was improved,and annulus abnormal pressure during the late production was reduced.This research provides a reference for the development of similar gasfields.展开更多
In Well MJ4,Tarim Basin,the testing tubing string is 6617 m long and the bottom-hole pressure during the testing is 101.63 MPa.During the completion job,plastic deformation occurs in the tubing string,so it is very ne...In Well MJ4,Tarim Basin,the testing tubing string is 6617 m long and the bottom-hole pressure during the testing is 101.63 MPa.During the completion job,plastic deformation occurs in the tubing string,so it is very necessary to figure out at which stage of the completion job plastic deformation occurs on earth.For this reason,the three-dimension finite element analysis method was used to perform numerical calculations for the deformation of tubing string and the distribution of axial stress based on three typical load conditions(setting load,fracturing load,and well testing load of Well MJ4);a process for calculating the mechanical behavior of a completion and testing tubing string containing an expansion joint was then developed.The study content mainly includes:(1)A criterion was developed to determine the extension and closure status of the expansion joint in the tubing string;corresponding calculation mechanism and formulae were provided;and the extensioneclosure status of the expansion joint in the tubing string for Well MJ4 was calculated.(2)A method was developed for analyzing and calculating the additional pressure difference load in the packer annulus caused by poor engagement of the hydraulic anchor;the impact of the additional pressure difference load on the deformation behavior of the tubing string was simulated;and the significant impact of the additional pressure difference load on the plastic buckling deformation was figured out.(3)The limit of lateral buckling deformation in a calculation model was introduced,and so the impact of collar rigidity on the buckling deformation was indirectly considered;the deformation under the joint action of all loads of the tubing string was calculated,and the numerical result was the same as the observed deformation.The study results show that the plastic deformation of the tubing string for Well MJ4 occurs at the fracturing stage and the major causes are hydraulic pressure loads and gravity loads in different forms.The conclusion shows that the mechanical calculation model of the testing tubing containing the expansion joint can be used as an important theoretical tool and analysis approach in optimizing operations and designing the tubing string structure.展开更多
In recent years,a series of major natural gas exploration discoveries and breakthroughs have been achieved in deep and ultra-deep carbonate gas reservoirs in the Sichuan Basin,and all discovered gas reservoirs are cha...In recent years,a series of major natural gas exploration discoveries and breakthroughs have been achieved in deep and ultra-deep carbonate gas reservoirs in the Sichuan Basin,and all discovered gas reservoirs are characterized by great burial depth,complex pore structures and high formation temperature and pore pressure.In order to accurately predict the gas flow rate of single well in high temperature and high pressure(HTHP)gas reservoirs and clarify the gas flow characteristics under formation conditions,this paper establishes a productivity simulation experimental device and method based on the formation temperature and pore pressure of carbonate gas reservoirs in the Middle Permian Qixia Formation of northwestern Sichuan Basin and the Upper Sinian Dengying Formation of central Sichuan Basin.Then,the cores of above mentioned gas reservoirs are selected to carry out the productivity simulation experiment under HTHP.Finally,the gas flow characteristics are studied.And the following research results are obtained.First,the newly established productivity simulation experimental device and method suitable for the conditions of 160℃ formation temperature and 100 MPa pore pressure is used to predict the natural gas AOF(absolute open flow)of Well S-1 in the Qixia Formation gas reservoir of northwestern Sichuan Basin.And the prediction result is better accordant with the calculation result of theoretical model,with a relative error of only 2.12%.Second,based on the Klinkenberg permeability under surface conditions,the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the gas flow rate from field completion testing;while based on the Klinkenberg permeability under formation conditions,the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the AOF.Third,the change of formation temperature and pore pressure has a significant influence on rock permeability,and the permeability is more sensitive to stress than to temperature.Fourth,to carry out the reservoir stress sensitivity experiment and the productivity simulation experiment,it is required that core samples be recovered to the formation conditions for aging,or the experimental results may have characteristics of strong stress sensitivity and cannot be used for reservoir engineering evaluation directly.In conclusion,the production rate and AOF of HTHP gas wells can be predicted accurately by means of productivity simulation experiment,based on drilling core samples.In addition,the Klinkenberg permeability under formation conditions can be evaluated by using the relational expression between surface or Klinkenberg permeability under formation conditions and single-well gas flow rate,combined with gas well testing data.展开更多
We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),a...We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),and investigated in detail by x-ray diffraction,electron microscope,magnetization and electrical resistivity measurements,etc.First-principles calculation based on density functional theory ab intio simulation was carried out to calculate the bonding and electromagnetic properties of Mn_(23)C_(6).Based on our experimental and simulated results,the Mn_(23)C_(6)in this work is single phase of a faced-centered cubic structure with space group Fm-3m(No.225).Determined by SEM and TEM,the bulk sample consists of monocrystal Mn_(23)C_(6)crystals with 2-15μm grain sizes,it is the quick quenching method in the synthesizing process that brings such small crystal grain size.Archimedes method gives its density of 7.14 g/cm^(3),95.74%of its theoretically calculated density 7.458 g/cm^(3).Owing to the abundant Mn 3d electrons and a framework of strongly linked Mn atoms in Mn_(23)C_(6),the electrical conductivity is up to 8.47×10^(-4)Ω·m,which shows that Mn_(23)C_(6)is a good conductor.Our magnetic susceptibility analyses reveal a magnetization peak in the M-T curve at 104 K,combined with the M-H curve and Curie-Weiss law,this peak usually means the transformation between paramagnetic and antiferromagnetic orders.To gain an insight into the mechanism of the magnetic phase transition,we calculated the magnetic properties,and the results show that different from normal antiferromagnetic order,the magnetic orders in Mn_(23)C_(6)consist of three parts,the direct ferromagnetic and antiferromagnetic exchange coupling interactions between Mn atoms,and the indirect antiferromagnetic super-exchange interaction between Mn and C atoms.Therefore,we reveal that the Mn_(23)C_(6)is a complex magnetic competition system including different magnetic orders and interactions,instead of the normal long-range antiferromagnetic order.展开更多
Deep oil and gas reservoirs exist under high-temperature conditions.In situ temperature-preserved coring(ITP-Coring)is an innovative and crucial method for evaluating and exploiting deep oil and gas resources.Thermal ...Deep oil and gas reservoirs exist under high-temperature conditions.In situ temperature-preserved coring(ITP-Coring)is an innovative and crucial method for evaluating and exploiting deep oil and gas resources.Thermal insulation materials are key to achieving successful ITP-Coring.Materials composed of hollow glass microspheres(HGMs)as fillers and epoxy resin(EP)as the matrix are promising thermal insulation materials for application in ITP-Coring to exploit deep resources.The compressive mechanical properties of these materials significantly influence their applicability and reliability.However,few studies have focused on the compressive mechanical behavior of the materials under high-temperature and high-pressure(HTHP)coupled conditions.Therefore,compressive mechanical tests on materials under temperatures and pressures of up to 150℃and 140 MPa were conducted innovatively.The compressive stress-strain curves of the materials were divided into three stages:elastic,yield,and failure,at temperatures ranging from 25℃to 100℃.Increasing temperature and pressure resulted in a decrease in compressive mechanical properties.Notably,high pressure damaged the HGMs,increasing compressive strain as the temperature rose.Additionally,the compressive failure mode shifted from compound failure to shear failure at different thresholds of HTHP conditions.Finally,a constitutive model of compressive mechanics that considered multiple coupled factors was established,demonstrating good agreement with the experimental results.These findings provide both experimental and theoretical support for the optimization and engineering application of HGMs/EP materials.展开更多
The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock ...The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock properties in deep reservoirs.High-performance thermal insulation materials are crucial for supporting ITP-Coring during deep oil and gas exploration.This study explores the impact of high-temperature and high-pressure(HTHP)conditions on hollow glass microsphere/epoxy(HGM/EP)thermal insulation materials,focusing on the interphase.Investigations of HGM/EP materials with varying hollow glass microsphere(HGM)strengths and volume fractions reveal that elevated temperatures cause the molecular chains of the epoxy resin matrix to relax,leading to matrix softening and a decline in mechanical properties.Additionally,high-pressure water infiltrates the material,damaging the interphase and HGMs,further compromising material performance.The combined HTHP environment accelerates this degradation.Dynamic mechanical analysis(DMA)shows that S60HS HGMs,which possess higher strength,interact more strongly with the matrix and exhibit higher entanglement density,resulting in superior interphase adhesion.This enhances stress transfer efficiency and reduces the loss of storage modulus at the interphase.Theoretical analysis indicates that the interphase thickness and modulus of S-f40 remain mostly unaffected after HTHP treatment,with values higher than the epoxy matrix.This correlates with DMA results,demonstrating that S-f40 has the smallest adhesion factor(A),indicating the highest interfacial stress transfer efficiency.S-f40 also exhibits optimal thermal conductivity and mechanical properties,making it ideal for ITP-Coring in deep reservoirs.These findings provide insights for optimizing materials in HTHP environments for deep reservoir exploration.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.52174047)the China Scholarship Council(No.202106440102)the PetroChina Strategic Cooperation Science and Technology Project(No.ZLZX 2020-01).
文摘In this work,the factors affecting asphaltenes deposition in high-temperature and high-pressure wells were studied using backscattered light and PVT equipment customized to suit the well conditions.In an examination of the intensity of backscattered light,it was revealed that there exists a linear relationship between temperature and asphaltene precipitation within a specific temperature range.Within this range,a decrease in temperature tends to accelerate asphaltene precipitation.However,the impacts of pressure and gas-oil ratio are more pronounced.The pressure depletion induces the asphaltenes to precipitate out of the solution,followed by the formation of flocs below the bubble point.In addition,an increase in the gas-oil ratio causes a more severe asphaltene deposition,shifting the location of asphaltenes to deep well sections.
基金supported by the Sichuan Science and Technology Program (Grant Nos.2023NSFSC0004,2023NSFSC0790)the National Natural Science Foundation of China (Grant Nos.51827901,52304033)the Sichuan University Postdoctoral Fund (Grant No.2024SCU12093)。
文摘Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.
基金Project supported by the National Manjor S&T Project“Development Demonstration Project of Large Carbonate Gas Field in Longgang Area,the Sichuan Basin”(No.2011ZX05047-02)Ph.D Station S&T Research Project of PetroChina Southwest Oil and Gas Field Company“Study on String Mechanics concerning to the Integrity of HTHP High-yield Gas Wells in the Longwangmiao Fm Reservoir”(No.20140305-11).
文摘For safe and efficient development of the sour gas reservoirs of the Cambrian Longwangmiao Fm in the Anyue Gas Field,the Sichuan Basin,and reduction of safety barrier failures and annulus abnormal pressure which are caused by erosion,corrosion,thread leakage and improper well completion operations,a series of studies and field tests were mainly carried out,including optimization of well completion modes,experimental evaluation and optimization of string materials,sealing performance evaluation of string threads,structural optimization design of downhole pipe strings and erosion resistance evaluation of pipe strings,after the technical difficulties related with the well completion in this reservoir were analyzed.And consequently,a set of complete well completion technologies suitable for HTHP(high temperature and high pressure)and highflowrate gas wells with acidic media was developed as follows.First,optimize well completion modes,pipe string materials and thread types.Second,prepare optimized string structures for different production allocation conditions.And third,formulate well completion process and quality control measures for vertical and inclined wells.Field application results show that the erosion of high-flowrate production on pipe strings and downhole tools and the effect of perforation on the sealing performance of production packers were reduced effectively,well completion quality was improved,and annulus abnormal pressure during the late production was reduced.This research provides a reference for the development of similar gasfields.
基金supported by the National Major Science and Technology Project“Optimal and fast ultra-deep HTHP well construction and gas recovery technologies”(No.:2016ZX05051003)the National Natural Science Foundation of China(General Program)“Theoretical and experimental studies on key mechanical aspects in unconventional gas recovery”(No.:11272216).
文摘In Well MJ4,Tarim Basin,the testing tubing string is 6617 m long and the bottom-hole pressure during the testing is 101.63 MPa.During the completion job,plastic deformation occurs in the tubing string,so it is very necessary to figure out at which stage of the completion job plastic deformation occurs on earth.For this reason,the three-dimension finite element analysis method was used to perform numerical calculations for the deformation of tubing string and the distribution of axial stress based on three typical load conditions(setting load,fracturing load,and well testing load of Well MJ4);a process for calculating the mechanical behavior of a completion and testing tubing string containing an expansion joint was then developed.The study content mainly includes:(1)A criterion was developed to determine the extension and closure status of the expansion joint in the tubing string;corresponding calculation mechanism and formulae were provided;and the extensioneclosure status of the expansion joint in the tubing string for Well MJ4 was calculated.(2)A method was developed for analyzing and calculating the additional pressure difference load in the packer annulus caused by poor engagement of the hydraulic anchor;the impact of the additional pressure difference load on the deformation behavior of the tubing string was simulated;and the significant impact of the additional pressure difference load on the plastic buckling deformation was figured out.(3)The limit of lateral buckling deformation in a calculation model was introduced,and so the impact of collar rigidity on the buckling deformation was indirectly considered;the deformation under the joint action of all loads of the tubing string was calculated,and the numerical result was the same as the observed deformation.The study results show that the plastic deformation of the tubing string for Well MJ4 occurs at the fracturing stage and the major causes are hydraulic pressure loads and gravity loads in different forms.The conclusion shows that the mechanical calculation model of the testing tubing containing the expansion joint can be used as an important theoretical tool and analysis approach in optimizing operations and designing the tubing string structure.
基金Project supported by the Scientific Research and Technology Development Project of PetroChina Company Limited“New Experimental Technology Development of Key Laboratory of Carbonate Reservoir”(No.:2018D-5006-35).
文摘In recent years,a series of major natural gas exploration discoveries and breakthroughs have been achieved in deep and ultra-deep carbonate gas reservoirs in the Sichuan Basin,and all discovered gas reservoirs are characterized by great burial depth,complex pore structures and high formation temperature and pore pressure.In order to accurately predict the gas flow rate of single well in high temperature and high pressure(HTHP)gas reservoirs and clarify the gas flow characteristics under formation conditions,this paper establishes a productivity simulation experimental device and method based on the formation temperature and pore pressure of carbonate gas reservoirs in the Middle Permian Qixia Formation of northwestern Sichuan Basin and the Upper Sinian Dengying Formation of central Sichuan Basin.Then,the cores of above mentioned gas reservoirs are selected to carry out the productivity simulation experiment under HTHP.Finally,the gas flow characteristics are studied.And the following research results are obtained.First,the newly established productivity simulation experimental device and method suitable for the conditions of 160℃ formation temperature and 100 MPa pore pressure is used to predict the natural gas AOF(absolute open flow)of Well S-1 in the Qixia Formation gas reservoir of northwestern Sichuan Basin.And the prediction result is better accordant with the calculation result of theoretical model,with a relative error of only 2.12%.Second,based on the Klinkenberg permeability under surface conditions,the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the gas flow rate from field completion testing;while based on the Klinkenberg permeability under formation conditions,the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the AOF.Third,the change of formation temperature and pore pressure has a significant influence on rock permeability,and the permeability is more sensitive to stress than to temperature.Fourth,to carry out the reservoir stress sensitivity experiment and the productivity simulation experiment,it is required that core samples be recovered to the formation conditions for aging,or the experimental results may have characteristics of strong stress sensitivity and cannot be used for reservoir engineering evaluation directly.In conclusion,the production rate and AOF of HTHP gas wells can be predicted accurately by means of productivity simulation experiment,based on drilling core samples.In addition,the Klinkenberg permeability under formation conditions can be evaluated by using the relational expression between surface or Klinkenberg permeability under formation conditions and single-well gas flow rate,combined with gas well testing data.
文摘We report the structural,mechanical and electromagnetic properties of the intermetallic compound Mn_(23)C_(6).The bulk Mn_(23)C_(6)sample was synthesized using high temperature high pressure quenching method(HTHPQM),and investigated in detail by x-ray diffraction,electron microscope,magnetization and electrical resistivity measurements,etc.First-principles calculation based on density functional theory ab intio simulation was carried out to calculate the bonding and electromagnetic properties of Mn_(23)C_(6).Based on our experimental and simulated results,the Mn_(23)C_(6)in this work is single phase of a faced-centered cubic structure with space group Fm-3m(No.225).Determined by SEM and TEM,the bulk sample consists of monocrystal Mn_(23)C_(6)crystals with 2-15μm grain sizes,it is the quick quenching method in the synthesizing process that brings such small crystal grain size.Archimedes method gives its density of 7.14 g/cm^(3),95.74%of its theoretically calculated density 7.458 g/cm^(3).Owing to the abundant Mn 3d electrons and a framework of strongly linked Mn atoms in Mn_(23)C_(6),the electrical conductivity is up to 8.47×10^(-4)Ω·m,which shows that Mn_(23)C_(6)is a good conductor.Our magnetic susceptibility analyses reveal a magnetization peak in the M-T curve at 104 K,combined with the M-H curve and Curie-Weiss law,this peak usually means the transformation between paramagnetic and antiferromagnetic orders.To gain an insight into the mechanism of the magnetic phase transition,we calculated the magnetic properties,and the results show that different from normal antiferromagnetic order,the magnetic orders in Mn_(23)C_(6)consist of three parts,the direct ferromagnetic and antiferromagnetic exchange coupling interactions between Mn atoms,and the indirect antiferromagnetic super-exchange interaction between Mn and C atoms.Therefore,we reveal that the Mn_(23)C_(6)is a complex magnetic competition system including different magnetic orders and interactions,instead of the normal long-range antiferromagnetic order.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB2390200)the National Natural Science Foundation of China(Grant No.52304033)the Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization(Grant No.DESGEEU-2023-10).
文摘Deep oil and gas reservoirs exist under high-temperature conditions.In situ temperature-preserved coring(ITP-Coring)is an innovative and crucial method for evaluating and exploiting deep oil and gas resources.Thermal insulation materials are key to achieving successful ITP-Coring.Materials composed of hollow glass microspheres(HGMs)as fillers and epoxy resin(EP)as the matrix are promising thermal insulation materials for application in ITP-Coring to exploit deep resources.The compressive mechanical properties of these materials significantly influence their applicability and reliability.However,few studies have focused on the compressive mechanical behavior of the materials under high-temperature and high-pressure(HTHP)coupled conditions.Therefore,compressive mechanical tests on materials under temperatures and pressures of up to 150℃and 140 MPa were conducted innovatively.The compressive stress-strain curves of the materials were divided into three stages:elastic,yield,and failure,at temperatures ranging from 25℃to 100℃.Increasing temperature and pressure resulted in a decrease in compressive mechanical properties.Notably,high pressure damaged the HGMs,increasing compressive strain as the temperature rose.Additionally,the compressive failure mode shifted from compound failure to shear failure at different thresholds of HTHP conditions.Finally,a constitutive model of compressive mechanics that considered multiple coupled factors was established,demonstrating good agreement with the experimental results.These findings provide both experimental and theoretical support for the optimization and engineering application of HGMs/EP materials.
基金work was funded by the National Natural Science Foun-dation of China(No.52304033)the National Key Research and Development Program of China(No.2023YFB2390200)Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization(No.DESGEEU-2023-10).
文摘The high-temperature conditions of deep oil and gas reservoirs notably affect the porosity and permeability of rocks.In situ temperature-preserved coring(ITP-Coring)technology is crucial for accurately assessing rock properties in deep reservoirs.High-performance thermal insulation materials are crucial for supporting ITP-Coring during deep oil and gas exploration.This study explores the impact of high-temperature and high-pressure(HTHP)conditions on hollow glass microsphere/epoxy(HGM/EP)thermal insulation materials,focusing on the interphase.Investigations of HGM/EP materials with varying hollow glass microsphere(HGM)strengths and volume fractions reveal that elevated temperatures cause the molecular chains of the epoxy resin matrix to relax,leading to matrix softening and a decline in mechanical properties.Additionally,high-pressure water infiltrates the material,damaging the interphase and HGMs,further compromising material performance.The combined HTHP environment accelerates this degradation.Dynamic mechanical analysis(DMA)shows that S60HS HGMs,which possess higher strength,interact more strongly with the matrix and exhibit higher entanglement density,resulting in superior interphase adhesion.This enhances stress transfer efficiency and reduces the loss of storage modulus at the interphase.Theoretical analysis indicates that the interphase thickness and modulus of S-f40 remain mostly unaffected after HTHP treatment,with values higher than the epoxy matrix.This correlates with DMA results,demonstrating that S-f40 has the smallest adhesion factor(A),indicating the highest interfacial stress transfer efficiency.S-f40 also exhibits optimal thermal conductivity and mechanical properties,making it ideal for ITP-Coring in deep reservoirs.These findings provide insights for optimizing materials in HTHP environments for deep reservoir exploration.
