Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability o...Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1) at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1) at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.展开更多
V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)i...V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation,which is noted VO-PPyd.The total density of states(TDOS)shows that after the pre-intercalation of PPyd,an intermediate energy level appears between the valence band and conduction band,which provides a step that can effectively reduce the band gap and enhance the electron conductivity.Furthermore,the density functional theory(DFT)results found that Zn^(2+)is more easily de-intercalated from the V-O skeleton,which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn^(2+).Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance(high specific capacity of 465 and 192 mA h g^(-1)at 0.2 and 10 A g^(-1),respectively)and long-term cycling performance(92.7%capacity retention rate after 5300 cycles),due to their advantages in structure and composition.More importantly,the energy density of VO-PPyd//Zn at 581 and 5806 W kg^(-1)is 375 and 247 W h kg^(-1),respectively.VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes,which makes it highly competitive in the field of high-performance cathode materials of AZIBs.展开更多
Paraffin deposition is a severe global problem during crude oil production and transportation.To inhibit the formation of paraffin deposits,the commonly used methods are mechanical cleaning,coating the pipe to provide...Paraffin deposition is a severe global problem during crude oil production and transportation.To inhibit the formation of paraffin deposits,the commonly used methods are mechanical cleaning,coating the pipe to provide a smooth surface and reduce paraffin adhesion,electric heating,ultrasonic and microbial treatments,the use of paraffin inhibitors,etc.Pipeline coatings not only have the advantages of simple preparation and broad applications,but also maintain a long-term efficient and stable effect.In recent years,important progress has been made in research on pipe coatings for mitigating and preventing paraffin deposition.Several novel superhydrophilic organogel coatings with low surface energy were successfully prepared by bionic design.This paper reviews different types of coatings for inhibiting wax deposition in the petroleum industry.The research prospects and directions of this rapidly developing field are also briefly discussed.展开更多
Background Myocardial infarction (MI) has likely contributed to the increased prevalence of heart failure (HF). As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi...Background Myocardial infarction (MI) has likely contributed to the increased prevalence of heart failure (HF). As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi and damage to the intestinal barrier. The induction of heme oxygenase-1 (HO-1) could prevent, or lessen the effects of stress and inflammation. Thus, the effect and mechanism thereof of HO-1 on the intestines of rats with HF was investigated. Methods Male Wistar rats with heart failure through ligation of the left coronary artery were identified with an left ventricular ejection fraction of 〈 45% through echocardiography and then divided into various experimental groups based on the type of peritoneal injection they received [MI: saline; MI + Cobalt protoporphyrin (CoPP): CoPP solution; and MI + Tin mesoporphyrin IX dichloride (SnMP): SnMP solution]. The control group was comprised of rats without coronary ligation. Echocardiogra- phy was performed before ligation for a baseline and eight weeks after ligation in order to evaluate the cardiac function of the rats. The bac- terial translocation (BT) incidence, mesenteric microcirculation, amount of endotoxins in the vein serum, ileum levels of HO- 1, carbon oxide (CO), nitric oxide (NO), intedeuldn (IL)-10, turnour necrosis factor-et (TNF-ct), and the ileum morphology were determined eight weeks after the operation. Results The rats receiving MI + CoPP injections exhibited a recovery in cardiac function, an amelioration of mesenteric microcirculation and change in morphology, a lower BT incidence, a reduction in serum and ileac NO and TNF-ct levels, and an elevation in ileac HO-1, CO, and interleukin-10 ([L-10) levels compared to the MI group (P 〈 0.05). The rats that received the MI + SnMP injections exhibited results inverse to the MI (P 〈 0.05) group. Conclusions HO-1 exerted a protective effect on the intestines of rats with HF by inhibiting the inflammation and amelioration of microcirculation through the CO pathway. This protective effect could be independent from the recovery of cardiac function.展开更多
Objective To investigate the quantities of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia and the relationship between quantities of CD5+ B lymphocytes and clinical or laboratorial parame...Objective To investigate the quantities of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia and the relationship between quantities of CD5+ B lymphocytes and clinical or laboratorial parameters. Methods Quantities of CD5+ B lymphocytes in the bone marrow of 14 patients with autoimmune hemolytic anemia (AIHA) or Evans syndrome, 22 immunorelated pancytopenia (IRP) patients, and 10 normal controls were assayed by flow cytometry. The correlation between their clinical or laboratorial parameters and CD5+ B lymphocytes was analyzed. Results The quantity of CD5+ B lymphocytes of AIHA/Evans syndrome (34.64%±19.81%) or IRP patients (35.81%±16.83%) was significantly higher than that of normal controls (12.00%±1.97%, P<0.05). However, there was no significant difference between AIHA/Evans syndrome and IRP patients (P>0.05). In all hemocytopenic patients, the quantity of bone marrow CD5+ B lymphocytes showed significantly negative correlation with serum complement C3 level (r=-0.416, P<0.05). In the patients with AIHA/Evans syndrome, the quantity of bone marrow CD5+ B lymphocytes showed significantly positive correlation with serum indirect bilirubin level (r=1.00, P<0.05). In Evans syndrome patients, the quantity of CD5+ B lymphocytes in bone marrow showed significantly positive correlation with platelet-associated immunoglobulin G (r=0.761, P<0.05) and platelet-associated immunoglobulin M (r=0.925, P<0.05). The quantity of CD5+ B lymphocytes in bone marrow of all hemocytopenic patients showed significantly negative correlation with treatment response (tau-b=-0.289, P<0.05), but had no correlation with colony forming unit-erythroid (r=-0.205, P>0.05) or colony forming unit-granulocyte-macrophage colonies (r=-0.214, P>0.05). Conclusions The quantity of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia significantly increases and is correlated with disease severity and clinical response, which suggest that CD5+ B lymphocytes might play an important role in the pathogenesis of autoimmune hemocytopenia.展开更多
In the Changqing Oilfield in northwest China, when traditional petroleum exploitation encounters forestry reserves or water source protection areas, sectorial well-factory design is proposed. The most distinct feature...In the Changqing Oilfield in northwest China, when traditional petroleum exploitation encounters forestry reserves or water source protection areas, sectorial well-factory design is proposed. The most distinct feature of a sectorial well-factory is the deviation of the well from the minimum horizontal principal stress, resulting in hydraulic fracture deflection after the initiation, along with possible well interference (i.e., fracture hit) and fracture coalescence in the oblique wells. Four indexes describing well deflection are then proposed according to fracture morphology. Several fracturing designs, including stage arrangement, fracturing sequences, and fracturing techniques are applied to study the feasibility of the sectorial well-factory design. The results show that the “gradual” or “sparse” stage arrangement, large injection rate, and simultaneous multifracture treatment can help to optimize the fracture morphology and stimulation design. However, the subsequent stress shadowing effect usually adversely affects the fracturing of adjacent wells. With a small initial horizontal stress difference, large injection rate and staggered stage arrangement can achieve ideal stimulation performance. Our results can provide a guidance for optimizing stimulation design in unconventional well-factory while taking into account environmental protection.展开更多
There is a significantly increasing demand of developing augmented reality and virtual reality(AR and VR) devices,where micro-LEDs(μLEDs) with a dimension of ≤ 5 μm are the key elements. Typically, μLEDs are fabri...There is a significantly increasing demand of developing augmented reality and virtual reality(AR and VR) devices,where micro-LEDs(μLEDs) with a dimension of ≤ 5 μm are the key elements. Typically, μLEDs are fabricated by dry-etching technologies, unavoidably leading to a severe degradation in optical performance as a result of dry-etching induced damages. This becomes a particularly severe issue when the dimension of LEDs is ≤ 10 μm. In order to address the fundamental challenge, the Sheffield team has proposed and then developed a direct epitaxial approach to achievingμLEDs, where the dry-etching technologies for the formation of μLED mesas are not needed anymore. This paper provides a review on this technology and then demonstrates a number of monolithically integrated devices on a single chip using this technology.展开更多
Objective To investigate the role of the burden of abnormal hematopoietic clone in the development of myelodysplastic syndromes (MDS). Methods The ratio of the bone marrow cells with abnormal chromosomes to the total ...Objective To investigate the role of the burden of abnormal hematopoietic clone in the development of myelodysplastic syndromes (MDS). Methods The ratio of the bone marrow cells with abnormal chromosomes to the total counted bone marrow cells was regarded as the index of MDS clone burden. The disease severity related parameters including white blood cell count, hemoglobin, platelet count, lactate dehydrogenase level, bone marrow blast, myeloid differentiation index, micromegakaryocyte, transfusion, interleukin-2, tumor necrosis factor (TNF), CD4^+ and CD8^+ T cells of MDS patients were assayed, and the correlations between those parameters and MDS clone burden were also analyzed. Results The clone burden of MDS patients was 67.4%±36.2%. MDS clone burden positively correlated with bone marrow blasts (r = 0.483, P<0.05), negatively with hemoglobin level (r=-0.445, P<0.05). The number of blasts, hemoglobin, and erythrocytes in high clone burden (>50%) and low clone burden (≤50%) groups were 7.78%±5.51% and 3.45%±3.34%, 56.06±14.28 g/L and 76.40±24.44 g/L, (1.82±0.48)×10~ 12 /L and (2.32±0.66)×10~ 12 /L, respectively (all P<0.05). CD4^+ T lymphocytes of MDS patients and normal controls were (0.274±0.719)×10~ 9 /L and (0.455±0.206)×10~ 9 /L, respectively (P<0.05). CD8^+ T lymphocytes of MDS patients and normal controls were (0.240±0.150)×10~ 9 /L and (0.305±0.145)×10~ 9 /L, respectively. The serum level of interleukin-2 of MDS patients (6.29±3.58 ng/mL) was significantly higher than normal control (3.11±1.40 ng/mL, P<0.05). The serum level of TNF of MDS patients and normal control group were 2.42±1.79 ng/mL and 1.68±0.69 ng/mL, respectively. The ratio of CD4 to CD8 was higher in high clone burden MDS patients (1.90±0.52) than that in low clone burden patients (0.97±0.44, P<0.05). Conclusion The quantitive clonal karyotype abnormalities and deficient T cell immunity are important parameters for evaluating MDS severity and predicting its progression.展开更多
Unconventional reservoirs usually contain many weak surfaces such as faults,laminae and natural fractures,and effective activation and utilization of these weak surfaces in reservoirs can significantly improve the ext...Unconventional reservoirs usually contain many weak surfaces such as faults,laminae and natural fractures,and effective activation and utilization of these weak surfaces in reservoirs can significantly improve the extraction effect.In hydraulic fracturing,when the artificial fracture approaches the natural fracture,the natural fracture would be influenced by both the original in-situ stress field and the hydraulic fracturing-induced stress field.In this paper,the hydraulic fracturing-induced stress field is calculated based on the relative position of hydraulic fracture and natural fracture,the original in-situ stress,the net pressure inside the hydraulic fracture and the pore pressure of the formation.Furthermore,the stability model of the natural fracture is established by combining the Mohr-Coulomb rupture criterion,and extensive parametric studies are conducted to explore the impact of each parameter on the stability of the natural fracture.The validity of the proposed model is verified by comparing with the reservoir characteristics and fracturing process of the X-well 150e155 formation in the Songliao Basin.It is found that the stress field induced by the hydraulic fracture inhibits the activation of the natural fracture after the artificial fracture crossed the natural fracture.Therefore,for similar reservoirs as X-well 150e155,it is suggested to connect natural fractures with hydraulic fractures first and then activate natural fractures which can effectively utilize the natural fractures and form a complex fracture network.展开更多
基金supported from Science and Technology Development Program of Jilin Province(Nos.20240101128JC,20230402058GH)National Natural Science Foundation of China(No.52130101).
文摘Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1) at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1) at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.
基金supported by the National Natural Science Foundation of China (21676036)the Natural Science Foundation of Chongqing (CSTB2023NSCQ-MSX0580)the Graduate Research and Innovation Foundation of Chongqing (CYB22043 and CYS22073)。
文摘V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation,which is noted VO-PPyd.The total density of states(TDOS)shows that after the pre-intercalation of PPyd,an intermediate energy level appears between the valence band and conduction band,which provides a step that can effectively reduce the band gap and enhance the electron conductivity.Furthermore,the density functional theory(DFT)results found that Zn^(2+)is more easily de-intercalated from the V-O skeleton,which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn^(2+).Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance(high specific capacity of 465 and 192 mA h g^(-1)at 0.2 and 10 A g^(-1),respectively)and long-term cycling performance(92.7%capacity retention rate after 5300 cycles),due to their advantages in structure and composition.More importantly,the energy density of VO-PPyd//Zn at 581 and 5806 W kg^(-1)is 375 and 247 W h kg^(-1),respectively.VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes,which makes it highly competitive in the field of high-performance cathode materials of AZIBs.
文摘Paraffin deposition is a severe global problem during crude oil production and transportation.To inhibit the formation of paraffin deposits,the commonly used methods are mechanical cleaning,coating the pipe to provide a smooth surface and reduce paraffin adhesion,electric heating,ultrasonic and microbial treatments,the use of paraffin inhibitors,etc.Pipeline coatings not only have the advantages of simple preparation and broad applications,but also maintain a long-term efficient and stable effect.In recent years,important progress has been made in research on pipe coatings for mitigating and preventing paraffin deposition.Several novel superhydrophilic organogel coatings with low surface energy were successfully prepared by bionic design.This paper reviews different types of coatings for inhibiting wax deposition in the petroleum industry.The research prospects and directions of this rapidly developing field are also briefly discussed.
文摘Background Myocardial infarction (MI) has likely contributed to the increased prevalence of heart failure (HF). As a result of re- duced cardiac function, splanchnic blood flow decreases, causing ischemia in villi and damage to the intestinal barrier. The induction of heme oxygenase-1 (HO-1) could prevent, or lessen the effects of stress and inflammation. Thus, the effect and mechanism thereof of HO-1 on the intestines of rats with HF was investigated. Methods Male Wistar rats with heart failure through ligation of the left coronary artery were identified with an left ventricular ejection fraction of 〈 45% through echocardiography and then divided into various experimental groups based on the type of peritoneal injection they received [MI: saline; MI + Cobalt protoporphyrin (CoPP): CoPP solution; and MI + Tin mesoporphyrin IX dichloride (SnMP): SnMP solution]. The control group was comprised of rats without coronary ligation. Echocardiogra- phy was performed before ligation for a baseline and eight weeks after ligation in order to evaluate the cardiac function of the rats. The bac- terial translocation (BT) incidence, mesenteric microcirculation, amount of endotoxins in the vein serum, ileum levels of HO- 1, carbon oxide (CO), nitric oxide (NO), intedeuldn (IL)-10, turnour necrosis factor-et (TNF-ct), and the ileum morphology were determined eight weeks after the operation. Results The rats receiving MI + CoPP injections exhibited a recovery in cardiac function, an amelioration of mesenteric microcirculation and change in morphology, a lower BT incidence, a reduction in serum and ileac NO and TNF-ct levels, and an elevation in ileac HO-1, CO, and interleukin-10 ([L-10) levels compared to the MI group (P 〈 0.05). The rats that received the MI + SnMP injections exhibited results inverse to the MI (P 〈 0.05) group. Conclusions HO-1 exerted a protective effect on the intestines of rats with HF by inhibiting the inflammation and amelioration of microcirculation through the CO pathway. This protective effect could be independent from the recovery of cardiac function.
文摘Objective To investigate the quantities of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia and the relationship between quantities of CD5+ B lymphocytes and clinical or laboratorial parameters. Methods Quantities of CD5+ B lymphocytes in the bone marrow of 14 patients with autoimmune hemolytic anemia (AIHA) or Evans syndrome, 22 immunorelated pancytopenia (IRP) patients, and 10 normal controls were assayed by flow cytometry. The correlation between their clinical or laboratorial parameters and CD5+ B lymphocytes was analyzed. Results The quantity of CD5+ B lymphocytes of AIHA/Evans syndrome (34.64%±19.81%) or IRP patients (35.81%±16.83%) was significantly higher than that of normal controls (12.00%±1.97%, P<0.05). However, there was no significant difference between AIHA/Evans syndrome and IRP patients (P>0.05). In all hemocytopenic patients, the quantity of bone marrow CD5+ B lymphocytes showed significantly negative correlation with serum complement C3 level (r=-0.416, P<0.05). In the patients with AIHA/Evans syndrome, the quantity of bone marrow CD5+ B lymphocytes showed significantly positive correlation with serum indirect bilirubin level (r=1.00, P<0.05). In Evans syndrome patients, the quantity of CD5+ B lymphocytes in bone marrow showed significantly positive correlation with platelet-associated immunoglobulin G (r=0.761, P<0.05) and platelet-associated immunoglobulin M (r=0.925, P<0.05). The quantity of CD5+ B lymphocytes in bone marrow of all hemocytopenic patients showed significantly negative correlation with treatment response (tau-b=-0.289, P<0.05), but had no correlation with colony forming unit-erythroid (r=-0.205, P>0.05) or colony forming unit-granulocyte-macrophage colonies (r=-0.214, P>0.05). Conclusions The quantity of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia significantly increases and is correlated with disease severity and clinical response, which suggest that CD5+ B lymphocytes might play an important role in the pathogenesis of autoimmune hemocytopenia.
基金funded by the National Natural Science Foundation of China(42077247,52104029)the Fundamental Research Funds for the Central Universities.
文摘In the Changqing Oilfield in northwest China, when traditional petroleum exploitation encounters forestry reserves or water source protection areas, sectorial well-factory design is proposed. The most distinct feature of a sectorial well-factory is the deviation of the well from the minimum horizontal principal stress, resulting in hydraulic fracture deflection after the initiation, along with possible well interference (i.e., fracture hit) and fracture coalescence in the oblique wells. Four indexes describing well deflection are then proposed according to fracture morphology. Several fracturing designs, including stage arrangement, fracturing sequences, and fracturing techniques are applied to study the feasibility of the sectorial well-factory design. The results show that the “gradual” or “sparse” stage arrangement, large injection rate, and simultaneous multifracture treatment can help to optimize the fracture morphology and stimulation design. However, the subsequent stress shadowing effect usually adversely affects the fracturing of adjacent wells. With a small initial horizontal stress difference, large injection rate and staggered stage arrangement can achieve ideal stimulation performance. Our results can provide a guidance for optimizing stimulation design in unconventional well-factory while taking into account environmental protection.
基金Project supported by the Engineering and Physical Sciences Research Council (EPSRC),U.K.,via EP/P006973/1,EP/T013001/1,and EP/M015181/1。
文摘There is a significantly increasing demand of developing augmented reality and virtual reality(AR and VR) devices,where micro-LEDs(μLEDs) with a dimension of ≤ 5 μm are the key elements. Typically, μLEDs are fabricated by dry-etching technologies, unavoidably leading to a severe degradation in optical performance as a result of dry-etching induced damages. This becomes a particularly severe issue when the dimension of LEDs is ≤ 10 μm. In order to address the fundamental challenge, the Sheffield team has proposed and then developed a direct epitaxial approach to achievingμLEDs, where the dry-etching technologies for the formation of μLED mesas are not needed anymore. This paper provides a review on this technology and then demonstrates a number of monolithically integrated devices on a single chip using this technology.
基金Supported by a grant from the Tianjin Natural Science Fund (013111111,023609311).
文摘Objective To investigate the role of the burden of abnormal hematopoietic clone in the development of myelodysplastic syndromes (MDS). Methods The ratio of the bone marrow cells with abnormal chromosomes to the total counted bone marrow cells was regarded as the index of MDS clone burden. The disease severity related parameters including white blood cell count, hemoglobin, platelet count, lactate dehydrogenase level, bone marrow blast, myeloid differentiation index, micromegakaryocyte, transfusion, interleukin-2, tumor necrosis factor (TNF), CD4^+ and CD8^+ T cells of MDS patients were assayed, and the correlations between those parameters and MDS clone burden were also analyzed. Results The clone burden of MDS patients was 67.4%±36.2%. MDS clone burden positively correlated with bone marrow blasts (r = 0.483, P<0.05), negatively with hemoglobin level (r=-0.445, P<0.05). The number of blasts, hemoglobin, and erythrocytes in high clone burden (>50%) and low clone burden (≤50%) groups were 7.78%±5.51% and 3.45%±3.34%, 56.06±14.28 g/L and 76.40±24.44 g/L, (1.82±0.48)×10~ 12 /L and (2.32±0.66)×10~ 12 /L, respectively (all P<0.05). CD4^+ T lymphocytes of MDS patients and normal controls were (0.274±0.719)×10~ 9 /L and (0.455±0.206)×10~ 9 /L, respectively (P<0.05). CD8^+ T lymphocytes of MDS patients and normal controls were (0.240±0.150)×10~ 9 /L and (0.305±0.145)×10~ 9 /L, respectively. The serum level of interleukin-2 of MDS patients (6.29±3.58 ng/mL) was significantly higher than normal control (3.11±1.40 ng/mL, P<0.05). The serum level of TNF of MDS patients and normal control group were 2.42±1.79 ng/mL and 1.68±0.69 ng/mL, respectively. The ratio of CD4 to CD8 was higher in high clone burden MDS patients (1.90±0.52) than that in low clone burden patients (0.97±0.44, P<0.05). Conclusion The quantitive clonal karyotype abnormalities and deficient T cell immunity are important parameters for evaluating MDS severity and predicting its progression.
基金funded by the subprojects of the National Key R&D Program of China(2020YFA0710600)the NSFC(National Natural Science Foundation of China,grant 42374132).
文摘Unconventional reservoirs usually contain many weak surfaces such as faults,laminae and natural fractures,and effective activation and utilization of these weak surfaces in reservoirs can significantly improve the extraction effect.In hydraulic fracturing,when the artificial fracture approaches the natural fracture,the natural fracture would be influenced by both the original in-situ stress field and the hydraulic fracturing-induced stress field.In this paper,the hydraulic fracturing-induced stress field is calculated based on the relative position of hydraulic fracture and natural fracture,the original in-situ stress,the net pressure inside the hydraulic fracture and the pore pressure of the formation.Furthermore,the stability model of the natural fracture is established by combining the Mohr-Coulomb rupture criterion,and extensive parametric studies are conducted to explore the impact of each parameter on the stability of the natural fracture.The validity of the proposed model is verified by comparing with the reservoir characteristics and fracturing process of the X-well 150e155 formation in the Songliao Basin.It is found that the stress field induced by the hydraulic fracture inhibits the activation of the natural fracture after the artificial fracture crossed the natural fracture.Therefore,for similar reservoirs as X-well 150e155,it is suggested to connect natural fractures with hydraulic fractures first and then activate natural fractures which can effectively utilize the natural fractures and form a complex fracture network.