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Corrosion damage mechanisms of nickel-based alloy G3 at 600 °C with a mixture of H2O, CO2, H2S and H2 were explored using ultra-high-temperature and high-pressure corrosion experiments, slow strain rate tensile tests and a series of microscopic characterization methods. Results unveil that G3 alloy exhibited a low corrosion rate on average. The corrosion product film consists of two layers – an inner layer of Cr2O3 and an outer layer of a mixture of Ni3S2 and Cr2O3. The material experienced plasticity losses of 49.5 % and 24.3 % after corrosion and aging, respectively. Precipitation of M23C6 at grain boundary occurred after corrosion and aging, resulting in chromium depletion and intergranular corrosion within weak grain boundary regions, which reduced plasticity of G3 alloy.

Based on previous studies, we established a thermodynamic model to calculate the equation of state (EOS) and longitudinal sound velocity (Vp) for liquid Fe and Fe -8. 6Si under high temperature and pressure. The calculated EOSs and Vp are consistent with measurements by static and dynamic compressions. Under the outer core conditions, EOS and V, of liquid Fe-8. 6Si simultaneously match the seismic data of the Earth's out- er core. If Si is the only light element, its maximum concentration in the outer core is estimated to be 7.6~8.6 wt%. [ABSTRACT FROM AUTHOR]

With the deepening of mine development level, the coal rock storage environment shows high gas pressure and high ground temperature characteristics, and temperature and pressure are important factors affecting the adsorption-desorption-oxidation characteristics of gas-bearing coal. In order to investigate the changes of gas desorption and spontaneous combustion characteristics in relic coal under high temperature and pressure, coal samples with different burial depths in high gas and prone spontaneous combustion mines were selected as test objects, and orthogonal tests for methane desorption from coal under different temperatures and pressures were designed, and pore and surface area tests, TG-FTIR coupling and programmed temperature rise tests were carried out on the original and desorbed coal samples. The results shown that, the inhibition of temperature was significantly greater than the promotion of pressure throughout the desorption experiments. The high temperature and pressure environment mainly changed the microporous structure of the coal, resulting in an increase in the specific surface area and total pore volume. After desorption, the temperature breakpoints of the 320 m and 343 m coal samples were advanced by 8.7% and 4.9%, while the same types of functional groups were present in the coals, but with different decreases in content. The cross-temperature points of CO generation in the desorbed and original coal samples from 320 m and 343 m were 78 ℃ and 74 ℃, respectively, and the concentrations of C2H4 and C2H6 were consistently lower than those in the original coal samples. Meanwhile, the oxygen consumption of desorbed coal samples decreased at the same coal temperature, and the difference was the largest at 170 ℃. The oxygen contents of coal samples before and after desorption at 320 m and 343 m were 9.3%, 13.1% and 10.3%, 14.3% respectively, and the maximum difference between the two oxygen consumption was 42.3% and 41.2%. The comprehensive analysis shown that, coal samples after high temperature and high pressure desorption were more prone to spontaneous combustion at the initial stage of oxidation and produce more CO, which can be selected as the indicator gas, while the reaction intensity was reduced at the high temperature stage. In addition, the formula of the real-time change of gas environment in the mining area by methane desorption in coal was introduced, and the “oxidation zone” area under the influence of gas desorption in coal left in the mining area under the characteristics of “high gas pressure and high ground temperature” was delineated in more detail using 1304 comprehensive mining face as a model, and the scope was reduced by 63.5%. The research results can provide basic support for the prevention and control of gas-fire coupling disasters in high gas-spontaneous combustion prone coal seams.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drilling into fractured formations can easily lead to mud loss, which significantly affects drilling efficiency and increases drilling costs. In high-temperature and high-pressure environments, changes in mud properties render mud loss more uncontrollable. On the basis of a mud performance test in a high-temperature and high-pressure environment, and considering the time-varying characteristics of wellbore temperature and pressure and the distribution law of fracture temperature and pressure, a coupling model of temperature and pressure in the wellbore and fracture was established in this study. The developed model was solved numerically using the finite difference approximation, and the characteristics of the mud loss were analyzed. The effects of geothermal gradient, fracture parameters (fracture width, fracture length, and deformation capacity), mud properties (viscosity, yield value, and specific heat capacity), and operating conditions on mud loss were investigated. The model was validated using field measurement-while-drilling tool data of the LD1 well in the South China Sea. The results show that the average errors between the calculated temperature and pressure results of the numerical model and the actual data are 2.45% and 0.57%, respectively, which proves that the model has high accuracy in the prediction of the bottom hole temperature and pressure. A comparison of the predicted data of mud loss with the actual measured data indicates that the average error of the mud leakage model is 4.23%. This also demonstrates that the model has a high accuracy in predicting mud loss. In addition, the results show that the mud performance changes significantly under high-temperature and high-pressure conditions, which has a significant influence on mud loss. The geothermal gradient affected the mud properties and thus significantly affected the mud loss characteristics. The larger the mud pumping rate, the larger the bottomhole pressure difference and the more serious the mud loss. Blindly increasing mud viscosity is not advisable because it may lead to more serious losses. With an increase in the mud yield value, the mud flow resistance in the fractures can be significantly increased to inhibit mud loss. The larger the mud-specific heat capacity, the less mud loss is affected by the temperature. With an increase in the fracture width, the degree of mud loss gradually decreased. The larger the fracture length and deformation capacity, the more serious the mud loss. The fracture length and width could be inverted using the developed model.

Aluminum-water reaction have the potential for clean hydrogen production and power generation. In this work, the effects of reactions such as temperature, pressure, water-aluminum ratio, and water state of the high-temperature and high-pressure aluminum-water reaction are experimentally investigated. The findings demonstrate that the micron aluminum powder can produce 100% hydrogen in a catalyst-free neutral environment by enhancing the temperature and pressure. The aluminum-water interaction is favored by excess water and the gas-liquid two-phase state. The effects of Na+ and K+ ions within water in high-temperature and high-pressure reactions under neutral environments have a negligible effect, and the in-situ reaction with clean water has a high hydrogen yield. The high-temperature and high-pressure aluminum-water reactions consist of four stages. Hydrogen and heat are generated only when water molecules and activated aluminum are constant touch. He results provide the foundation for aluminum-water-based hydrogen cogeneration. • High temperature and pressure reduce the complexity and cost of the reaction. • The reaction can achieve 100% hydrogen yield through increased temperature and pressure. • High temperature, high pressure and excess water facilitate the reaction. • High reaction efficiency can be obtained even with on-site water sources. [ABSTRACT FROM AUTHOR]

The stress threshold of deep reservoir shale subjected to fracturing fluid immersion is an important factor affecting fracture initiation and propagation during fracturing. However, little information has been reported on the effect on shale of soaking at high temperature and high pressure (HTHP). In this study, immersion tests and triaxial compression tests were carried out at reservoir temperature and in-situ stress on the downhole cores with different mineral compositions. The characteristics of stress thresholds, i.e., crack initiation stress ( σ c i ), crack damage stress ( σ cd ), and peak deviator stress ( σ p ), of shale affected by the different times of soaking with low-viscosity fracturing fluid (a) and the different viscosity fracturing fluids (a, b, and c) were investigated. The results show that hydration at HTHP has a significant softening effect on the stress thresholds ( σ c i , σ cd , σ p ) of reservoir shale, but the softening rate varies for samples with different mineral compositions. The crack initiation stresses of quartz-rich and clay-rich shales treated with different soaking times and different soaking media remain almost unchanged in the range of 47 to 54% of the corresponding peak strength, while the crack initiation stresses of carbonate-rich shales are significantly affected. The ratio σ cd / σ p of quartz-rich shale is significantly affected by the different viscosity fracturing fluids (a, b) and the different times of soaking with low-viscosity fracturing fluid (a), while clay- and carbonate-rich shales are less affected. The results of this study can provide a reference for the fracturing design of deep shale gas development. [ABSTRACT FROM AUTHOR]

The application of sericin hydrogels is limited mainly due to their poor mechanical strength, tendency to be brittle and inconvenient sterilization. To address these challenges, a sericin hydrogel exhibiting outstanding physical and chemical properties along with cytocompatibility was prepared through crosslinking genipin with degraded sericin extracted from fibroin deficient silkworm cocoons by the high temperature and pressure method. Our reported sericin hydrogels possess good elasticity, injectability, and robust behaviors. The 8% sericin hydrogel can smoothly pass through a 16 G needle. While the 12% sericin hydrogel remains intact until its compression ratio reaches 70%, accompanied by a compression strength of 674 kPa. 12% sericin hydrogel produce a maximum stretch of 740%, with breaking strength and tensile modulus of 375 kPa and 477 kPa respectively. Besides that, the hydrogel system demonstrated remarkable cell-adhesive capabilities, effectively promoting cell attachment and, proliferation. Moreover, the swelling and degradation behaviors of the hydrogels are pH responsiveness. Sericin hydrogel releases drugs in a sustained manner. Furthermore, this study addresses the challenge of sterilizing sericin hydrogels (sterilization will inevitably lead to the destruction of their structures). In addition, it challenges the prior notion that sericin extracted under high temperature and pressure is difficult to directly cross-linked into a stable hydrogel. This developed hydrogel system in this study holds promise to be a new multifunctional platform expanding the application area scope of sericin. [ABSTRACT FROM AUTHOR]

The reliability of the aircraft engine duct system is of paramount importance as it directly affects the safety of the aircraft, particularly under high-temperature and high-pressure cycles. In this study, ANSYS Workbench was used for finite element analysis, and a sleeve-type tie rod structure was proposed to address the critical problem of tie rod tearing during the operation of the duct system, thereby optimizing thermal stress compensation for the duct system. The research results show the following: (1) The anchor of the traditional tie rod imposes displacement constraints on the thermal deformation of the duct system, leading to stress concentration and even structural failure in the connection area between a duct and a tie rod. (2) The improved sleeve-type tie rod provides greater axial displacement freedom for the duct, effectively mitigating stress concentration phenomena. (3) Taking a worst-case scenario of 537.78 °C and 2 MPa as an example, the sleeve-type tie rod proposed in this paper can reduce the stress at the tie rod connection from 757.61 MPa to less than 25 MPa, a reduction of more than 96%. The original tie rod tearing problem is solved, and the maximum stress of the whole duct system is reduced to 459.25 MPa, which is below the yield strength. [ABSTRACT FROM AUTHOR]

Rock wetting behaviour and CO2/brine interfacial tension (IFT) have significant impacts on enhanced hydrocarbon recovery (EOR) and carbon geo-sequestration (CGS) projects. Influence of nanoparticles/surfactant solutions (NPS) flooding on EOR and CGS in sandstone and carbonate formation have been examined in recent studies. But the impact of NPS on carbon dioxide (CO2) and methane (CH4) wettabilities of organic-rich shale and CO2/brine IFT is presently unclear. Thus, we measured contact angles, [advancing (θa)and receding (θr)] for CO2/brine and CH4/brine on Marcellus shale with high total organic carbon (14.8 wt%), as well as CO2/brine IFT with Krüss drop shape analyzer (DSA 100) through the sessile drop and pendant drop techniques. Prior to IFT and contact angles measurement, the shale samples were aged in NPS solutions to evaluate the impact of NPS treatment on CO2 geo-storage. Low-cost rice husk silica nanoparticles and saponin surfactant were used for the study due to their environmental friendliness and economic attractiveness. At geo-storage conditions (25 MPa and 353 K), the advancing contact angle of untreated shale was measured as θa=116.22° (CO2-wet condition), whereas the receding contact angle was measured as θr=82.88° (near neutral wettability). However, θareduced by 56.34° whereas θrreduced by 56.76° when the shale substrate was treated with 0.1 wt% SiO 2 and 0. 2 wt% saponin solutions. CO2/NPS IFT were lower than CO2/brine IFT and the CH4 wettability of the Marcellus shale was significantly lower than the CO2 wettability at all investigated conditions. Contact angles decreased with temperature and increased with CO2/CH4 pressure, whereas CO2/NPS IFT exhibited an opposite trend. The reduction in contact angles and CO2/brine IFT by NPS have significant impacts on adsorption trapping of CO2in organic-rich shale and hydrocarbon recovery from unconventional shale reservoirs.

The application of sericin hydrogels is limited mainly due to their poor mechanical strength, tendency to be brittle and inconvenient sterilization. To address these challenges, a sericin hydrogel exhibiting outstanding physical and chemical properties along with cytocompatibility was prepared through crosslinking genipin with degraded sericin extracted from fibroin deficient silkworm cocoons by the high temperature and pressure method. Our reported sericin hydrogels possess good elasticity, injectability, and robust behaviors. The 8% sericin hydrogel can smoothly pass through a 16 G needle. While the 12% sericin hydrogel remains intact until its compression ratio reaches 70%, accompanied by a compression strength of 674 kPa. 12% sericin hydrogel produce a maximum stretch of 740%, with breaking strength and tensile modulus of 375 kPa and 477 kPa respectively. Besides that, the hydrogel system demonstrated remarkable cell-adhesive capabilities, effectively promoting cell attachment and, proliferation. Moreover, the swelling and degradation behaviors of the hydrogels are pH responsiveness. Sericin hydrogel releases drugs in a sustained manner. Furthermore, this study addresses the challenge of sterilizing sericin hydrogels (sterilization will inevitably lead to the destruction of their structures). In addition, it challenges the prior notion that sericin extracted under high temperature and pressure is difficult to directly cross-linked into a stable hydrogel. This developed hydrogel system in this study holds promise to be a new multifunctional platform expanding the application area scope of sericin.

The stress threshold of deep reservoir shale subjected to fracturing fluid immersion is an important factor affecting fracture initiation and propagation during fracturing. However, little information has been reported on the effect on shale of soaking at high temperature and high pressure (HTHP). In this study, immersion tests and triaxial compression tests were carried out at reservoir temperature and in-situ stress on the downhole cores with different mineral compositions. The characteristics of stress thresholds, i.e., crack initiation stress (σci), crack damage stress (σcd), and peak deviator stress (σp), of shale affected by the different times of soaking with low-viscosity fracturing fluid (a) and the different viscosity fracturing fluids (a, b, and c) were investigated. The results show that hydration at HTHP has a significant softening effect on the stress thresholds (σci, σcd, σp) of reservoir shale, but the softening rate varies for samples with different mineral compositions. The crack initiation stresses of quartz-rich and clay-rich shales treated with different soaking times and different soaking media remain almost unchanged in the range of 47 to 54% of the corresponding peak strength, while the crack initiation stresses of carbonate-rich shales are significantly affected. The ratio σcd/σp of quartz-rich shale is significantly affected by the different viscosity fracturing fluids (a, b) and the different times of soaking with low-viscosity fracturing fluid (a), while clay- and carbonate-rich shales are less affected. The results of this study can provide a reference for the fracturing design of deep shale gas development.

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The reliability of the aircraft engine duct system is of paramount importance as it directly affects the safety of the aircraft, particularly under high-temperature and high-pressure cycles. In this study, ANSYS Workbench was used for finite element analysis, and a sleeve-type tie rod structure was proposed to address the critical problem of tie rod tearing during the operation of the duct system, thereby optimizing thermal stress compensation for the duct system. The research results show the following: (1) The anchor of the traditional tie rod imposes displacement constraints on the thermal deformation of the duct system, leading to stress concentration and even structural failure in the connection area between a duct and a tie rod. (2) The improved sleeve-type tie rod provides greater axial displacement freedom for the duct, effectively mitigating stress concentration phenomena. (3) Taking a worst-case scenario of 537.78 °C and 2 MPa as an example, the sleeve-type tie rod proposed in this paper can reduce the stress at the tie rod connection from 757.61 MPa to less than 25 MPa, a reduction of more than 96%. The original tie rod tearing problem is solved, and the maximum stress of the whole duct system is reduced to 459.25 MPa, which is below the yield strength.

Combined with the high pressure and high temperature working condition and the characteristics of tooth and sliding ring combined seal, the mathematical model of the rotating slip ring type combined seal is established based on the theory of thermoelastic hydrodynamic lubrication. Furthermore, the elastic deformation of the tooth and sliding ring combined seal under the action of oil film pressure is obtained by the matrix method of deformation influence coefficient based on the theory of small deformation. Combined with the hydrodynamic lubrication equation, the temperature field energy equation and the viscosity temperature equation, the finite difference method is used to solve the thermoelastic flow pressure lubrication model. The oil film thickness distribution and oil film pressure distribution in the working process of the combined seal ring of the toothed slip ring are calculated by MATLAB. The results show that the roughness of the ring has a significant effect on the sealing performance. The film pressure increases first and then decreases in the axial direction, and fluctuates in the stable range in the circumferential direction.Moreover, the oil film thickness and pressure of the sealing ring decrease with the increase of the ambient temperature.

Germination and processing are always accompanied by significant changes in the metabolic compositions of rice. In this study, polished rice (rice), brown rice, wet germinated brown rice (WGBR), high temperature and pressure-treated WGBR (WGBR-HTP), and low temperature-treated WGBR (WGBR-T18) were enrolled. An untargeted metabolomics assay isolated 6 122 positive ions and 4 224 negative ions (multiple difference ≥1.2 or ≤0.8333, P

Abstract Performing stress‐sensitivity evaluation on a high‐temperature and high‐pressure gas reservoir is essential for correctly understanding the characteristics of physical property changes and reasonably designing the development scheme of a reservoir under stratum conditions. By focusing on six core samples with different physical properties in a gas field in the Yingqiong Basin, stress‐sensitivity experiments have been conducted along with mercury intrusion porosimetry and X‐ray diffraction measurements to study the relationship among porosity, permeability, and effective stress at a temperature of 140°C and effective stress ranging from 2 MPa to 70 MPa. Our results showed that the stress‐sensitivity curve characterized by three‐stage segmentation is primarily affected by average pore radius and mineral composition but has no direct relation with porosity and permeability. Meanwhile, the stress sensitivity of permeability is mainly related to the average pore throat radius and mineral composition of core specimen. The smaller the pore throat radius and the higher the clay content, the stronger the stress sensitivity of permeability. Under high‐temperature and high‐pressure conditions, the stress sensitivities of permeability and porosity can be characterized by power functions although the stress sensitivity of permeability is about 2–11 times higher than that of porosity.

Abstract The elastic modulus is a key parameter in the constitutive equation of rock material, which changes with exterior conditions, including temperature. To study the evolution of the elastic modulus of the surrounding rock in some high‐temperature underground engineering works (eg, underground coal gasification, in situ pyrolysis of oil shale), a servo‐controlled rock testing machine was used in a study of the variation in elastic modulus of Jimsar mudstone (the roof stratum of Jimsar oil shale) when subjected to triaxial compression at high temperatures. The elastic modulus exhibited nonmonotonal variation when heated to 400°C while subjected to triaxial compression. This occurred in three stages. An empirical model involving piecewise linear function was used to quantitatively describe the relationship between elastic modulus and temperature. Elasticity increased between room temperature and 265°C, then weakened between 265 and 341°C, then increased at 341‐400°C, in accordance with the calculated result from the empirical model. Thermal expansion, thermal cracking, water loss, and structure reconstruction had a combined effect on the elastic modulus of the mudstone. The results will be helpful for understanding the mechanism of strata movement in some underground high‐temperature engineering operations.

In order to reveal the shale oil production mechanism and production efficiency under the energy-depleted development mode, experiments on expulsion oil based on imbibition and elastic energy release under high temperature and pressure were carried out, and nuclear magnetic resonance on-line monitoring was used to observe the production characteristics of shale oil. The experimental results show that the imbibition-expulsion oil mainly occurs in the small-size pore-throat system. Under the condition of high temperature and pressure, the oil-expulsion efficiency is generally less than 2% affected by pore pressure, which is significantly different from the conventional imbibition experiment results. Although elastic-energy expulsion oil occurs in different sizes of pore-throat systems, the oil-expulsion efficiency in large size pore-throat systems is more sensitive to temperature. Overall, the total elastic-energy oil-expulsion efficiency is significantly positively correlated with reservoir physical properties, production differential pressure and temperature, and negatively correlated with crude oil viscosity. Comprehensively considering various geological factors affecting oil-expulsion efficiency, the shale oil production efficiency evaluation model under the energy-depleted development mode is constructed, and the movable oil porosity of shale oil development section in the study area is evaluated. The results show that there is a good positive correlation between movable oil porosity and oil production intensity. The movable oil porosity of dry layer is generally lower than 0.5% and that of poor oil layer is between 0.5% and 1.5%. When the movable oil porosity is between 1.5 and 2.5%, it can be determined as the type II oil layer, and for more than 2.5%, it is the type I oil layer. The single-well evaluation results show that the shale oil “sweet spots” of the Lucaogou Formation in Jimsar Sag are mainly distributed in P2l22−1∼ P2l22−3 and P2l12−1∼ P2l12−3, which is in good agreement with the current development status.

• Moisture decreases adsorption capacity of shales to CO 2 under reservoir conditions. • CO 2 adsorption/desorption changes organic matter and inorganic minerals of shales. • CO 2 -induced pore alterations cause adsorption and desorption hysteresis on shales. • Moisture raises hysteresis by dissolving CO 2 and promoting mineral dissolution. • Moisture weakens injectivity but strengthens storage stability of CO 2. To understand injectivity and storage stability of CO 2 into gas-bearing shale reservoirs, CO 2 adsorption and desorption on the dry and moist shales with diverse properties were conducted at 353.15 K and pressures up to 14 MPa. Multiple characterizations were combined to examine pore characteristics of the shales before and after CO 2 adsorption/desorption. The resultant CO 2 adsorption and desorption hysteresis on the shales was revealed ultimately. Results indicated that both the excess and absolute adsorption isotherms of CO 2 witness slow increase stage, rapid increase stage, and decrease stage. The adsorption capability of the shales positively depends on the TOC content and pore abundance. Moreover, the clay minerals and oxygenic functional groups also benefit CO 2 adsorption. The moisture significantly reduces the experimentally-determined maximum absolute adsorption capacity of the shales by 5.78–46.39 % due to pore space occupation. During the adsorption/desorption, the CO 2 molecules could interact with the shales, thereby initiating extraction of partial organic matter, transformation of CO 2 from supercritical state to gas state, and dissolution of inorganic minerals. Those effects consume CO 2 and dominantly change the micropore structure of the dry shales and the mesopore structure of the moist shales, thus leading to CO 2 adsorption and desorption hysteresis. Notably, the moisture dramatically raises the hysteresis degree on the shales by 8.42–59.45 % because of its solubility to CO 2 and promotion to mineral dissolution. Overall, shale reservoir moisture could weaken injectivity but strengthen storage stability of CO 2. Hence, the critical moisture content and occurrence pattern of organic matter and clay minerals are required for target shale reservoir selection. [ABSTRACT FROM AUTHOR]

Qiongdongnan Basin has a tectonic geological background of high temperature and high pressure in a deep reservoir setting, with mantle‐derived CO2. A water‐rock reaction device was used under high temperature and high pressure conditions, in conjunction with scanning electron microscope (SEM) observations, to carry out an experimental study of the diagenetic reaction between sandstone at depth and CO2‐rich fluid, which is of great significance for revealing the dissolution of deep clastic rock reservoirs and the developmental mechanism of secondary pores, promoting deep oil and gas exploration. In this study, the experimental scheme of the water‐rock reaction system was designed according to the parameters of the diagenetic background of the deep sandstone reservoir in the Qiongdongnan Basin. Three groups of single mineral samples were prepared in this experiment, including K‐feldspar samples, albite samples and calcite samples. Using CO2 as a reaction solution, a series of diagenetic reaction simulation experiments were carried out in a semi‐closed high temperature and high pressure simulation system. A field emission scanning electron microscope (SEM) was used to observe the microscopic appearance of the mineral samples after the water‐rock reaction, the characteristics of dissolution under high temperature and high pressure, as well as the development of secondary pores. The experimental results showed that the CO2‐rich fluid has an obvious dissolution effect on K‐feldspar, albite and calcite under high temperature and high pressure. For the three minerals, the main temperature and pressure window for dissolution ranged from 150°C to 300°C and 45 MPa to 60 MPa. Scanning electron microscope observations revealed that the dissolution effect of K‐feldspar is most obvious under conditions of 150°C and 45 MPa, in contrast to conditions of 200°C and 50 MPa for albite and calcite. Through the comparative analysis of experimental conditions and procedures, a coupling effect occurred between the temperature and pressure change and the dissolution strength of K‐feldspar, albite and calcite. Under high temperature and high pressure, pressure changed the solubility of CO2, furthermore, the dissolution effect and strength of the sandstone components were also affected. The experiment revealed that high temperature and high pressure conditions with CO2‐rich fluid has a significant dissolution effect on aluminosilicate minerals and is conducive to the formation of secondary pores and effective reservoirs. Going forward with the above understanding has important implications for the promotion of deep oil and gas exploration. [ABSTRACT FROM AUTHOR]

Performing stress‐sensitivity evaluation on a high‐temperature and high‐pressure gas reservoir is essential for correctly understanding the characteristics of physical property changes and reasonably designing the development scheme of a reservoir under stratum conditions. By focusing on six core samples with different physical properties in a gas field in the Yingqiong Basin, stress‐sensitivity experiments have been conducted along with mercury intrusion porosimetry and X‐ray diffraction measurements to study the relationship among porosity, permeability, and effective stress at a temperature of 140°C and effective stress ranging from 2 MPa to 70 MPa. Our results showed that the stress‐sensitivity curve characterized by three‐stage segmentation is primarily affected by average pore radius and mineral composition but has no direct relation with porosity and permeability. Meanwhile, the stress sensitivity of permeability is mainly related to the average pore throat radius and mineral composition of core specimen. The smaller the pore throat radius and the higher the clay content, the stronger the stress sensitivity of permeability. Under high‐temperature and high‐pressure conditions, the stress sensitivities of permeability and porosity can be characterized by power functions although the stress sensitivity of permeability is about 2–11 times higher than that of porosity. [ABSTRACT FROM AUTHOR]

The elastic modulus is a key parameter in the constitutive equation of rock material, which changes with exterior conditions, including temperature. To study the evolution of the elastic modulus of the surrounding rock in some high‐temperature underground engineering works (eg, underground coal gasification, in situ pyrolysis of oil shale), a servo‐controlled rock testing machine was used in a study of the variation in elastic modulus of Jimsar mudstone (the roof stratum of Jimsar oil shale) when subjected to triaxial compression at high temperatures. The elastic modulus exhibited nonmonotonal variation when heated to 400°C while subjected to triaxial compression. This occurred in three stages. An empirical model involving piecewise linear function was used to quantitatively describe the relationship between elastic modulus and temperature. Elasticity increased between room temperature and 265°C, then weakened between 265 and 341°C, then increased at 341‐400°C, in accordance with the calculated result from the empirical model. Thermal expansion, thermal cracking, water loss, and structure reconstruction had a combined effect on the elastic modulus of the mudstone. The results will be helpful for understanding the mechanism of strata movement in some underground high‐temperature engineering operations. [ABSTRACT FROM AUTHOR]

Air-assisted steam injection is used as a secondary or tertiary oil recovery technology. During closing, downhole tubular goods are subject to corrosion in a mixed oxygen–steam–hot solution environment. This study investigates the influence of air injection pressure, temperature and Cl− ion concentration in the injection water on the corrosion of P110 steel. Results show that high air injection pressure for increasing oil recovery ratio leads to the highly aggressive corrosion. The trend of corrosion rate and temperature in air-saturated injection water is a reversed 'V' curve. However, the high Cl− concentration, which promotes the formation of large holes in the magnetite scale, greatly reduces corrosion. A suitable injection press that balances the oil recovery ratio and corrosion rate of oil tube, avoiding 170°C suitable for the highest corrosion rate, and periodic removing corrosion scales are necessary to inhibit further deterioration of downhole tubular goods. [ABSTRACT FROM AUTHOR]

In the production process of high-temperature and high-pressure gas wells, it is very important to understand the changes of the temperature and pressure parameters in the wellbore with the depth of the well. Based on the conservation of fluid energy, momentum, and mass in the wellbore, considering the influence of high-temperature and high-pressure gas wells on the temperature and pressure of the wellbore under the coupling of fluid velocity, density, and Joule–Thomson effect, a wellbore temperature and pressure prediction model was established based on this. Then, we could obtain wellbore temperature and pressure distribution along the well depth. The comparison with the actual wellbore data of Tarim X gas well and XX well in Southwest China shows that the calculation result of the multifactor coupling model is less than 3% of the field measured data, which verifies the accuracy of the multifactor coupling model result. Based on this, the effects of different gas production and production time on the temperature and pressure of high-temperature and high-pressure gas well boreholes were analyzed. The results show that for the Tarim X gas well, when the gas production is 80 × 104, 90 × 104 and 100 × 104 m3/day, the corresponding wellhead temperatures are 56.1, 65.3, and 69.8 °C; the corresponding wellhead pressures are 62.4, 62.2, and 62.0 MPa. When the production time is 1 day, 10 days, and 20 days, the corresponding wellhead temperatures are 61.5, 63.6, and 64.8 °C, respectively; the corresponding wellhead pressures are 63, 62.8, and 62.4 MPa. [ABSTRACT FROM AUTHOR]

Canola meal, a by‐product of oil pressing, is a rich source of phenolic antioxidants. However, its use in the food and feed sector is still limited by the need for greener, sustainable, and more cost‐effective extraction methods. This study used accelerated solvent extraction (ASE) to enhance the extraction efficiency of the phenolic antioxidants. The high selectivity and short extraction time associated with ASE were ideal for obtaining high yields of these antioxidants. The structure‐based activity of phenolic compounds may be influenced by the high pressure and temperature of the greener ASE process. The present study evaluated the effect of temperature (140, 160, and 180 °C) and pressure (1,500 psi) on the extraction and yield of phenolic compounds from canola meal as well as the solvent type (ethanol and methanol) and concentration (30%, 40%, 60%, and 70% v/v). Antioxidant activity was determined by 2,2‐diphenyl‐1‐picrylhydrazyl, ferric reducing/antioxidant power assay, and ion‐chelating activity. The highest yield of phenolic compounds was obtained with 70% methanol (20.72 ± 1.47 mg SAE/g DM [milligrams of sinapic acid equivalents per gram of dry matter]) and 70% ethanol (24.71 ± 2.77 mg SAE/g DM) at 180 °C temperature. A similar trend was observed for the antioxidant activity of the extracts and their total flavonoid content. The structure‐based antioxidant activity of the extracts examined increased with the increase in the percentage of the extracting solvent (P > 0.05). This study established ASE as an efficient green method for extracting phenolic compounds from canola meal, with potential application for the production of natural bioactive compounds from underutilized agricultural by‐products. Practical Application: ASE is an efficient eco‐friendly method for extracting phenolic compounds from agricultural by‐products such canola meal. Under the conditions of high pressure and temperature, ASE significantly improved the yields of phenolic compounds, sinapine, sinapic acid, and canolol. Under these conditions, water, as an extractant, was not effective in extracting sianpine. Moreover, it was much less effective than both 70% ethanol and 70% methanol in extracting sinapine or canolol. These phenolic compounds are of great interest as natural antioxidants for enhancing the shelf life of food products. They also represent new sources of neutraceuticals for improving human health. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing consumes massive volumes of freshwater that is usually scarce and costly. Such operation is not sustainable, and hence seawater could be used as an alternative. Nevertheless, seawater has high total dissolved solids (TDS), affecting the fracturing fluid rheology and providing a damage potential to the subterranean hydrocarbon reservoirs. Resolving these issues requires fracturing fluid systems with many additives, which results in an expensive and non-eco-friendly system. This study proposes eco-friendly and biodegradable chelating agents that could replace many additives such as scale inhibitors and crosslinkers. The study aims to optimize the rheology of seawater fracturing fluids using a chelating agent and polymer. By optimizing N,N-Dicarboxymethyl glutamic acid (GLDA) conditions, high viscosity was achieved using a standard industry rheometer. The GLDA was mixed with carboxymethyl hydroxypropyl guar (CMHPG) polymer and tested in both deionized water (DW) and seawater (SW). The polymer was examined first, where the rheology did not show a time-dependent behavior. The polymer in SW showed a slightly higher viscosity than in DW. The GLDA and CMHPG were tested at different temperatures, pH, and concentrations. These sets showed a time-dependent viscosity behavior, which can be utilized in various fracturing steps. Results showed that the solution pH and GLDA concentration significantly impacted the fluid viscosity magnitude and behavior. The developed formulation is shear thinning, where the viscosity declines as the shear rate increases. The temperature negatively impacted the viscosity and caused the formulation to break. The study provided an understanding of how to optimize the rheology of SW fracturing fluid based on GLDA chelating and CMHPG polymer.

Abstract Using the self-developed viscosity measuring device, the viscosity variations of coal–oil slurries with temperature increasing during coal–oil co-processing were studied. The results show that the viscosity of coal–oil slurries prepared by different kinds of oil varies differently during heating. The viscosity of the coal–oil slurry prepared by the catalytic cracking slurry (FCC) generally decreases during heating. However, the viscosity of the coal–oil slurry prepared by the high-temperature coal tar (CT) will peak at 338 °C during heating. The differences in viscosity variations of coal–oil slurries are analyzed. In addition to the temperature, the properties of the solvents and coal are the main influencing factors. Because the used coal contains a large number of polar functional groups, the swelling behavior of the coal in polar solvent (CT) is stronger than that in non-polar solvent (FCC). The swelling effect of the coal can result in the appearance of the viscosity peak. Therefore, before 100 °C, the solvent molecules entering into the coal pores is the main influencing factor of coal–oil slurries viscosity variations. After 100 °C, the increasing of particle size of coal particles is the main influencing factor of coal–oil slurries viscosity variations.

The specimen is a reactor pressure vessel with a semi-elliptical surface crack with axial orientation and its 3D finite element numerical modeling is built. Based on J-A2 two parameters method,analysis is performed by considering constraint effect,at T = 561 K,p = 10 MPa. Three different aspect ratio（ a/c） and Ramberg-Osgood exponent（ n） is analylized,namely a/c = 1/2,1/3,1/5（ a = 20 mm,c = 40 mm,60 mm,100 mm） and n = 10,15,20. The corresponding J-integral and constraint parameter A2 is gained. The research results show that: J-integral increases with the decrease of aspect ratio a/c,and RambergOsgood exponent（ n） almost has no effect on J-integral. The increase of Ramberg-Osgood exponent（ n） will weaken the effect of aspect ratio a/c on A2. The most serious point is the deepest point of a crack.

In the process of developing hot dry rock (HDR) through enhanced geothermal systems (EGS), it is necessary to inject circulating water to complete thermal energy extraction. However, the injected water will react with the high-temperature rock and produce mineral dissolution, which can destroy the artificial reservoir and affect the development of geothermal energy. To explore the influence of temperature on the solution composition and mineral dissolution after water-rock reaction, this study conducted water-rock interaction experiments on gabbro and granite at different heat treatment temperatures. Subsequently, the changes of solution composition and mineral dissolution with temperature after the reaction were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and XRD. The results demonstrated that Si, Na, Ca, K, Al, and Mg did not enter the aqueous solution at the same dissolution rate. Si was the primary solute in the solution, mainly resulting from the dissolution of quartz, and the dissolution rates of metallic elements were lower. In the granite-water interaction system, metallic elements such as Na, K, Ca, and Al showed a tendency to enter the solution at low temperatures, i.e., 150-180 °C, and the dissolution rate of Si reached its peak when the water was close to the supercritical state. With the increase in temperature, the dissolution rates of Si and metallic elements showed an initial increasing trend followed by a decrease. When water is in the subcritical to the supercritical state, abrupt fluctuations in the physical properties of water can strongly affect the dissolution of minerals or rocks. The results of this study provide insights into rock corrosion fatigue and mineral scaling in EGS water environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In continuation of our early works, an experimental study of the kinetics and interaction mechanisms in the hydrogen-basalt melt system at a hydrogen pressure of 100 MPa and temperature of 1250°C carried out. It was found in kinetic experiments that, despite the high reduction potential of the H2-melt system, the hydrogen oxidation reactions and the complete reduction of Fe oxides in the melt do not go to the end. As a result, initially homogeneous basalt melt becomes heterogeneous: H2O is formed in the fluid phase; H2O is dissolved in the basalt melts, and a small metal separation of the liquation structure formed at a temperature significantly lower than the melting temperature of the metal phases (Fe, FeNiCo alloy). The structure and dimensions of the experimentally established metal separations agree well with the natural data on the findings of small amounts of the metal phase, primarily iron and its alloys with nickel and cobalt, reported from magmatic rocks of various compositions and origins. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • CO 2 and N 2 flooding experiments were performed in tight cores under high pressure and temperature. • Low-field NMR technique was used to monitor pore-scale displacement and quantify improvement. • CO 2 flooding created a uniform displacement front due to the local oil-CO 2 interactions. • The small and large pores nearly contributed equally to the overall oil recovery for N 2 flooding. • The incremental oil recovery was mainly contributed by large pores for CO 2 flooding. Abstract Recent reports have demonstrated that gas injection can improve oil recovery of tight reservoirs after natural depletion, with major projects in progress worldwide. There is however a lack of understanding of the gas displacement behaviors at pore-scale especially under reservoir conditions. Herein we conducted an experimental investigation of CO 2 and N 2 flooding in the Lucaogou tight formation at 35.0 MPa and 80 °C. The flooding dynamics were continuously monitored by use of low-field nuclear magnetic resonance (NMR) to map the displacement processes at pore-scale and quantify the reduction of oil saturation in-situ. We observed that the overall oil recoveries of CO 2 and N 2 flooding were 38.4% and 35.1%, respectively. Due to the interactions between the oil phase and CO 2 , a uniform displacement along the core plug was yielded by CO 2 flushing, indicated by the 1D spatial distribution of local oil saturation and 2D transverse images. Interestingly, during CO 2 flooding, the major reduction of NMR T 2 signals occurred in the large pores (4.2 ms < T 2 < 252.4 ms), whereas in the case of N 2 flooding, the main change was found both in small pores (T 2 < 4.5 ms) and large pores (4.5 ms < T 2 < 432.3 ms). The results of this study supplement earlier observations from pore scale and can provide insights into oil recovery improvement of tight reservoirs. [ABSTRACT FROM AUTHOR]

Aiming at problem of high-temperature and high-pressure for geological drilling, a deep-well trajectory detector was designed to solve the problem, and multi-point continuous drilling inclinometers and temperature measurement. Strapdown type fiber snakes and MEMS chips are used to implement borehole measurements. The two-position north seeking algorithm is used. Corrective measures such as correction error, anti-jamming, and temperature compensation are used to measure attitude parameters and ensure measurement accuracy. The controller is designed to realize the acquisition, storage, transmission and power management of posture parameters, and high-temperature components are used to solve the operation of the high-temperature environment. The mechanical structure is designed to use insulation pipe and pressure tube to solve the problem of high temperature and high pressure. ANSYS finite element software is used to check the strength outer pipe structure under high pressure, and complete the coupling analysis of the insulation temperature probe and pressure field. Through simulation and testing, the instrument has achieved deep borehole inclination, azimuth angle, instrument tool orientation and temperature measurement under 300 °C and 120 MPa environmental condition. [ABSTRACT FROM AUTHOR]

We provide an experimental confirmation of the suggestion, based on thermodynamic simulations and extrapolations (Zhong et al. 2015), that Zn is transported in the form of chloride complexes in most acidic, shallow hydrothermal systems; while bisulfide complexes become increasingly important in deep, pH neutral to basic hydrothermal systems. We used in situ X‑ray absorption spectroscopy (XAS) diamond-anvil cell experiments to determine Zn(II) speciation in a 1 m NaHS + 0.2 m HCl solution in contact with sphalerite. XANES data indicate that Zn coordinates to oxy/hydroxyl/chloride ligands from room temperature up to and including 200 °C, and then at higher temperatures (≥300 °C) and pressures (>2 kbar) it changes to complexing with sulfur. Our data confirm that bisulfide complexes become increasingly important in neutral-alkaline solutions at high pressure and temperature, due to an increase in sulfur solubility and to favorable entropy contributions for bisulfide vs. chloride complexes. [ABSTRACT FROM AUTHOR]

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TC11 alloy is a promising structural material, and has a wide range of applications in many corrosive and high temperature hydrothermal systems. The passive film has an important influence on its electrochemical behavior. In this study, in-situ electrochemical methods (that is, open circuit potential (OCP), linear polarization (LP) and electrochemical impedance spectroscopy (EIS)) were used to monitor the long period electrochemical behavior of TC11 alloy in 0.01 M Na2SO4 solution at 300 °C/10 MPa. The growth kinetics of the passive film was mainly studied. The correlation between the evolution of the electrochemical behavior and the growth of the oxide film was discussed. The results showed that although the OCP gradually stabilized after twenty thousand seconds, henceforth the polarization resistance (Rp) was still increasing due to the thickening of the passive film. An equivalent circuit was proposed to fit the EIS experimental data, leading to determination of film capacitance and film resistance. Besides, the electrochemical data was interpreted in terms of the point defect model (PDM). The EIS results are consistent with the Rp results.

We report the initiation mechanisms and subsequent chemical decompositions of energetic metal-organic frameworks (MOFs) nickel hydrazine nitrate (NHN) crystal at high temperatures and high temperatures coupled with high pressures by ab initio molecular dynamics simulations. The initial decomposition step is the collapse of the MOF cage at 518 K and 518 K coupled with 1, 2, and 3 GPa. But their cleavage steps are different. It is found that the pressure decelerates the initial decomposition of the NHN crystal. The decomposition mechanisms of the NHN crystal at 518 K coupled with 20.2 GPa are much different from those at 518 K coupled with low pressures. The results indicate that the temperature is the foremost factor that affected the decomposition of the NHN crystal. At 4000 K and 4000 K coupled with 20.2 GPa, the initial decomposition mechanisms of NHN are both the cage collapse by several Ni N bond breaking. The variation tends and the release times of H 2 O are similar at the two cases. In the early decomposition stage, NHN decomposed very fast and drastically. But the later decomposition was slow. During 1.0 ps, there are ten H 2 O released fast at the two extreme conditions. Then the population of H 2 O keeps nearly stable during the later decomposition stage. At 7.959 ps, last one H 2 O was formed. Our results may provide useful information for understanding the chemical decompositions of energetic metal-organic frameworks compounds. [ABSTRACT FROM AUTHOR]

An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P-T parameters (4 GPa, 1400°C) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts. [ABSTRACT FROM AUTHOR]

Although studies about the origin of life are a frontier in science and a number of effective approaches have been developed, drawbacks still exist. Examples include: (1) simulation of chemical evolution experiments (which were demonstrated for the first time by Stanley Miller); (2) approaches tracing back the most primitive life-like systems (on the basis of investigations of present organisms); and (3) constructive approaches for making life-like systems (on the basis of molecular biology), such as in vitro construction of the RNA world. Naturally, simulation experiments of chemical evolution under plausible ancient Earth environments have been recognized as a potentially fruitful approach. Nevertheless, simulation experiments seem not to be sufficient for identifying the scenario from molecules to life. This is because primitive Earth environments are still not clearly defined and a number of possibilities should be taken into account. In addition, such environments frequently comprise extreme conditions when compared to the environments of present organisms. Therefore, we need to realize the importance of accurate and convenient experimental approaches that use practical research tools, which are resistant to high temperature and pressure, to facilitate chemical evolution studies. This review summarizes improvements made in such experimental approaches over the last two decades, focusing primarily on our hydrothermal microflow reactor technology. Microflow reactor systems are a powerful tool for performing simulation experiments in diverse simulated hydrothermal Earth conditions in order to measure the kinetics of formation and degradation and the interactions of biopolymers. [ABSTRACT FROM AUTHOR]

Multivariate optical computing (MOC) is a compressed sensing technique with the ability to provide accurate spectroscopic compositional analysis in a variety of different applications to multiple industries. Indeed, recent developments have demonstrated the successful deployment of MOC sensors in downhole/well-logging environments to interrogate the composition of hydrocarbon and other chemical constituents in oil and gas reservoirs. However, new challenges have necessitated sensors that operate at high temperatures and pressures (up to 230 °C and 138 MPa) as well as even smaller areas that require the miniaturization of their physical footprint. To this end, this paper details the design, fabrication, and testing of a novel miniature-sized MOC sensor suited for harsh environments. A micrometer-sized optical element provides the active spectroscopic analysis. The resulting MOC sensor is no larger than two standard AAA batteries yet is capable of operating in high temperature and pressure conditions while providing accurate spectroscopic compositional analysis comparable to a laboratory Fourier transform infrared spectrometer.

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using the self-developed viscosity measuring device, the viscosity variations of coal-oil slurries with temperature increasing during coal-oil co-processing were studied. The results show that the viscosity of coal-oil slurries prepared by different kinds of oil varies differently during heating. The viscosity of the coal-oil slurry prepared by the catalytic cracking slurry (FCC) generally decreases during heating. However, the viscosity of the coal-oil slurry prepared by the high-temperature coal tar (CT) will peak at 338 °C during heating. The differences in viscosity variations of coal-oil slurries are analyzed. In addition to the temperature, the properties of the solvents and coal are the main influencing factors. Because the used coal contains a large number of polar functional groups, the swelling behavior of the coal in polar solvent (CT) is stronger than that in non-polar solvent (FCC). The swelling effect of the coal can result in the appearance of the viscosity peak. Therefore, before 100 °C, the solvent molecules entering into the coal pores is the main influencing factor of coal-oil slurries viscosity variations. After 100 °C, the increasing of particle size of coal particles is the main influencing factor of coal-oil slurries viscosity variations. [ABSTRACT FROM AUTHOR]