Production induced fracture closure of deep shale gas well under thermo-hydro-mechanical conditions

Deep shale gas reservoirs have geological characteristics of high temperature,high pressure,high stress,and inferior ability to pass through fluids.The multi-stage fractured horizontal well is the key to exploiting the deep shale gas reservoir.However,during the production process,the effectiveness of the hydraulic fracture network decreases with the closure of fractures,which accelerates the decline of shale gas production.In this paper,we addressed the problems of unclear fracture closure mechanisms and low accuracy of shale gas production prediction during deep shale gas production.Then we established the fluid—solid—heat coupled model coupling the deformation and fluid flow among the fracture surface,proppant and the shale matrix.When the fluid—solid—heat coupled model was applied to the fracture network,it was well solved by our numerical method named discontinuous discrete fracture method.Compared with the conventional discrete fracture method,the discontinuous discrete fracture method can describe the three-dimensional morphology of the fracture while considering the effect of the change of fracture surface permeation coefficient on the coupled fracture—matrix flow and describing the displacement discontinuity across the fracture.Numerical simulations revealed that the degree of fracture closure increases as the production time proceeds,and the degree of closure of the secondary fractures is higher than that of the primary fractures.Shale creep and proppant embedment both increase the degree of fracture closure.The reduction in fracture surface permeability due to proppant embedment reduces the rate of fluid transfer between matrix and fracture,which has often been overlooked in the past.However,it significantly impacts shale gas production,with calculations showing a 24.7%cumulative three-year yield reduction.This study is helpful to understand the mechanism of hydraulic fracture closure.Therefore,it provides the theoretical guidance for maintaining the long-term effectiveness of hydraulic fractures.

Evaluating patients' perception of service quality at hospitals in nine Chinese cities by use of the ServQual scale

Objective: To investigate patients' perception of service quality at hospitals in nine Chinese cities and propose some measures for improvement. Methods: The ServQ ual scale method was used in a survey involving patients at out-patient and in-patient facilities in Shanghai, Chongqing, Chengdu, Nanning, Guilin and Laibin of Guangxi, Honghezhou of Yunnan, Wulumuqi of Xinjiang and Zhongshan of Guangdong. The data collected were entered and analyzed using SPSS 20.0. Statistical analyses included descriptive statistics, factor analyses, reliability analyses, product-moment correlations, independent-sample t-tests, One-way ANOVA and regression analyses. Results: The Kaiser-Meyer-Olkin value for the factor analysis of the scale was 0.979. The Cronbach's α for the reliability analysis was 0.978. All the Pearson correlation coei cients were positive and statistically signii cant. Visitors to out-patient facilities reported more positive perception tacilities on tangibles(t = 4.168, P(t = 1.979, P <han visitors to in-patient f 0.05). Patients of 60 years of age and above reported mor< 0.001) and reliability e positive perception th<an those between 40 and 49 on reliability(F = 3.311, P = 0.010), assurances(F = 2.751, P 0.05) and empathy(F = 4.009, P = 0.003). For the i ve dimensions of the scale, patients in Laibin, Guangxi reported the most positive perceived service quality, followed by patients in Shanghai. On the other hand, patients in Chongqing and Nanning and Guilin of Guangxi reported relatively poor perceptions of service quality. Standardized regression coei cients showed statistically significant(P < 0.001) positive values for all Serv Qual dimensions. Empathy(β = 0.267) and reliability(β uality. = 0.239) most strongly predicted perception of service qConclusions: Chinese patients perceived service quality as satisfactory. Hospitals in various regions of China should enhance their awareness and ability to serve their patients.

A scenario analysis of oil and gas consumption in China to 2030 considering the peak CO_2 emission constraint

China is now beginning its 13th five-year guideline. As the top CO2 emitter, China has recently submitted the intended nationally determined contributions and made the commitment to start reducing its total carbon emissions in or before 2030. In this study, a bottom-up energy system model is built and applied to analyze the energy （mainly coal, oil, and gas） consumption and carbon emissions in China up to 2030. The results show that, the total energy consumption will reach a peak of 58.1 billion tonnes of standard coal and the CO2 emissions will get to 105.8 billion tonnes. Moreover, in the mitigation scenario, proportion of natural gas consumption will increase by 7 % in 2020 and 10 % in 2030, respectively. In the trans- portation sector, gasoline and diesel consumption will gradually decrease, while the consumption of natural gas in 2030 will increase by 2.7 times compared to the reference scenario. Moreover, with the promotion of electric cars, the transport electricity consumption will increase 3.1 times in 2030 compared to the reference scenario. In order to fulfill the emission peaking target, efforts should be made from both the final demand sectors and oil and gas production industries, to help adjust the energy structure and ensure the oil and gas supply in future.

Review on the petroleum market in China:history,challenges and prospects

The petroleum industry plays an essential role in driving China's economic development.In the past few decades,severa reforms in the petroleum industry have been implemented;however,there are still some is sues that have not been resolved Moreover,with the new-normal economy,the transition to green energy and international trade disputes,the petroleum marke is also facing emerging challenges.Therefore,the purpose of the present study is to review the historical development o China's petroleum market,identify the current challenges and propose corresponding countermeasures for future prospects As a conclusion,five main challenges are highlighted totally,namely lack of marketization,excess oil refining capacity,hig external dependency,environment pollution and unstable international trading relationship.To address these challenges it is encouraged to deepen petroleum market reform,accelerate the elimination of inefficient refining capacity,diversify of supply sources,as well as improve domestic petroleum enterprises'ability to resist price risks.

Study of the impacts of upstream natural gas market reform in China on infrastructure deployment and social welfare using an SVM-based rolling horizon stochastic game analysis

Natural gas is expected to play a much more important role in China in future decades, and market reform is crucial for its rapid market penetration. At present, the main gas fields, pipelines and liquefied natural gas(LNG) infrastructure are mainly monopolized by large state-owned companies, and one of the important market reform policies is to open up LNG import rights to smaller private companies and traders. Therefore, in the present study, a game theoretical model is proposed to analyze and compare the impacts of different market structures on infrastructure deployment and social welfare. Moreover, a support vector machine-based rolling horizon stochastic method is adopted in the model to simulate real LNG price fluctuations. Four market reform scenarios are proposed considering different policies such as business separation, third-party access(TPA) and their combinations. The results indicate that, with third-party access(TPA)entrance into the LNG market, the construction of LNG infrastructure will be promoted and more gas will be provided at lower prices, and thus the total social welfare will be improved greatly.

Increased Cthrcl Activates Normal Fibroblasts and Suppresses Keloid Fibroblasts by Inhibiting TGF-β/Smad Signal Pathway and Modulating YAP Subcellular Location

Keloid may induce severe impairment of life quality for the patients,although keloid is a cutaneous benign tumor.Collagen triple helix repeat containing protein 1 (Cthrc1) was identified as a novel gene that was originally found in adventitial fibroblasts after arterial injury.To address the role of Cthrcl in keloid,the expression level of Cthrcl was assessed in normal skin and keloid tissue,as well as in normal fibroblasts (NFs)and keloid fibroblasts (KFs)by using quantitative PCR,Western blotting and immunohistochemical analysis.The results showed that Cthrcl was increased in keloid tissue and KFs as compared with normal skin and NFs.Meanwhile,CCK8 and Transwell assays found the cellular proliferation and migration of KFs were increased as compared with NFs.Further,to verify the function of Cthrcl in NFs and K.Fs,we increased Cthrcl expression by transfecting lentivirns (LV) vectors LV-Cthrcl.The cellular proliferation and migration,collagen synthesis and the influence on TGF-β and YAP signaling were tested.The cellular proliferation and migration were increased in NFs-Cthrcl as compared with NFs-control.Meanwhile,YAP expression and nuclear-location was increased in NFs-Cthrcl.On the contrary,when Cthrcl was overexpressed in KFs,the cellular migration was suppressed and YAP expression was reduced and transferred to cytoplasm in KFs-Cthrcl as compared with KFs-control.But the expression level of collagen I was decreased and pSmad2/3 nucleus transfer was suppressed in both NFs-Cthrc1 and KFs-Cthrc1 by using Western blotting and immunofluorescence.Increased Cthrcl activated NFs by promoting YAP nucleus translocation,whereas suppressed KFs by inhibiting YAP nucleus translocation.Enhanced Cthrcl decreased collagen I in both NFs and KFs by inhibiting TGF-β/Smad pathway.In conclusion,Cthrcl may play a role in the pathogenesis of keloid by inhibiting collagen synthesis and fibroblasts migration via suppressing TGF-β/Smad pathway and YAP nucleus translocation.

Effects of Total-Ionizing-Dose Irradiation on Single-Event Burnout for Commercial Enhancement-Mode AlGaN/GaN High-Electron Mobility Transistors

We investigate the synergism effect of total ionizing dose(TID)on single-event burnout(SEB)for commercial enhancement-mode AlGaN/GaN high-electron mobility transistors.Our experimental results show that the slight degradation of devices caused by gamma rays can affect the stability of the devices during the impact of high energy particles.During heavy ion irradiation,the safe working values of drain voltage are significantly reduced for devices which have already been irradiated by 60Co gamma rays before.This could be attributed to more charges trapped caused by 60Co gamma rays,which make GaN devices more vulnerable to SEB.Moreover,the electrical parameters of GaN devices after 60Co gamma and heavy-ion irradiations are presented,such as the output characteristic curve,effective threshold voltages,and leakage current of drain.These results demonstrate that the synergistic effect of TID on SEB for GaN power devices does in fact exist.

Effects of aspirin on fracture healing in OPF rats

Objective:To study the effect of aspirin on healing process of osteoporotic fracture(OPF)in rats.Methods:A total of 50 female Wistar rata aged 3 months were randomly divided into observation group and control group,castration method was adopted to establish the osteoporosis(OP)model.After artificial preparing fractures on the midpoint of left femur,fixing gram needle intramedullary.OPF modeling was complete.Aspirin lavage of 33 mg once a day was adoptde in observation group after modeling,same amount of normal saline was used in the control as placebo.From eash group,selected 5 rats at the 2nd.4th,8th and 12th week after modeling to measure the bone mineral density(BMD)and histogical examination of the fracture callus,radiology observation was conducted at the 8th and 12th week.Left femur biomechanical measurement was taken at the 12th week.Results:BMD values of observation group at each time point were significantly higher than that of the control group after modeling(P<0.05);Histological observation showed that at the 8th week,the endochondral ossification process of observation group was faster than that of observation group,with fuzzy fracture line in observation group and clear fracture line in observtion group;at the 12th week,fracture line disappeared in observation group,fracture line of the control group was fuzzy at the same time;three-point bending load of the left femur in observation group rats was significantly higher than that of control group after12 weeka(P<0.05).Conclusions:Asporin can accelerate the healing of new callus in OPF rats,increase bone density and biomechanics strength,and promote fracture of osteporotic rats.

Review on the challenges and strategies in oil and gas industry's transition towards carbon neutrality in China

In light of carbon-neutral pledge, the oil and gas industry has been facing several critical new challenges in China. The current status and new challenges in terms of market mechanism reform, supply-consumption balance and key technology innovation in China's oil and gas industry are reviewed in the present study, and new strategies and roadmaps are proposed to cope with the challenges. The study found that (i) the oil and gas market faces challenges such as incomplete pricing mechanisms, unclear subject rights, and the lack of recognition and trading of carbon assets. (ii) the trade-off between short-term supply security and long-term low-carbon supply is the most critical issue. (iii) in addition to typical challenges such as immature technology and lack of funding support, the unclear multiple technology coupling development mode also poses problems for the low-carbon transformation of the oil and gas industry. To address these new challenges, comprehensive strategies and roadmaps for China's oil and gas industry towards carbon neutrality are proposed and discussed in the aspects of participating in market transactions, restructuring production and consumption, deploying key technology innovations, and planning enterprise strategies. The present study is expected to provide a blueprint for the future development of China's oil and gas industry towards carbon neutrality.

Shaly detritus embedded epoxy-resin coated proppants

Proppant plays a significant role in the hydraulic fracturing process, which can affect the production of oil and gas wells. Due to the high density and low adhesion force, the settling speed of traditional proppants is fast, which will lead to the blockage of a crack channel. In this study, a proppant with double layer structure is fabricated by coating epoxy-resin and shaly detritus on ceramic proppants for the first time,respectively. The epoxy-resin enables the shaly detritus to be coated on the proppant successfully, which can provide a new method for shaly detritus treatment. The adhesive ability of shaly detritus and epoxyresin coated proppants(SEPs) is improved by 10.4% under the load force of 500 n N, which prolongs the time for the fracture to close. At the same time, the suspending ability of SEPs is two times higher than the uncoated proppants. Once the guar gum solution concentration is 0.3 wt%, the settling time of SEPs is36.7% longer than that of the uncoated proppants, which can effectively reduce the settlement of proppants in the crack. In addition, the hydrophobicity of the SEPs is enhanced, which reduces the wateroil ratio of crude oil and increases the liquid conductivity tested by deionized water. In summary, this new proppant is expected to promote the development of unconventional oil and gas resources.

Data-Driven Exploration of Polymer Processing Effects on the Mechanical Properties in Carbon Black-Reinforced Rubber Composites

The performance and corresponding applications of polymer nanocomposites are highly dominated by the choice of base material,type of fillers,and the processing ways.Carbon black-filled rubber composites(CRC)exemplify this,playing a crucial role in various industries.However,due to the complex interplay between these factors and the resulting properties,a simple yet accurate model to predict the mechanical properties of CRC,considering different rubbers,fillers,and processing techniques,is highly desired.This study aims to predict the dispersion of fillers in CRC and forecast the resultant mechanical properties of CRC by leveraging machine learning.We selected various rubbers and carbon black fillers,conducted mixing and vulcanizing,and subsequently measured filler dispersion and tensile performance.Based on 215 experimental data points,we evaluated the performance of different machine learning models.Our findings indicate that the manually designed deep neural network(DNN)models achieved superior results,exhibiting the highest coefficient of determination(R^(2))values(>0.95).Shapley additive explanations(SHAP)analysis of the DNN models revealed the intricate relationship between the properties of CRC and process parameters.Moreover,based on the robust predictive capabilities of the DNN models,we can recommend or optimize CRC fabrication process.This work provides valuable insights for employing machine learning in predicting polymer composite material properties and optimizing the fabrication of high-performance CRC.

Minimally invasive surgery alone compared with intensity-modulated radiotherapy for primary stage I nasopharyngeal carcinoma

Background:The National Comprehensive Cancer Network guidelines recommend intensity-modulated radiotherapy(IMRT)as the primary curative treatment for newly diagnosed nasopharyngeal carcinoma(NPC),but the radiation-related complications and relatively high medical costs remain a consequential burden for the patients.Endoscopic nasopharyngectomy(ENPG)was successfully applied in recurrent NPC with radiation free and relatively low medical costs.In this study,we examined whether ENPG could be an effective treatment for localized stage I NPC.Methods:Ten newly diagnosed localized stage I NPC patients voluntarily received ENPG alone from June 2007 to September 2017 in Sun Yat-sen University Cancer Center.Simultaneously,the data of 329 stage I NPC patients treated with IMRT were collected and used as a reference cohort.The survival outcomes,quality of life(QOL),and medical costs between two groups were compared.Results:After a median follow-up of 59.0 months(95%CI 53.4-64.6),no death,locoregional recurrence,or distant metastasis was observed in the 10 patients treated with ENPG.The 5-year overall survival,local relapse-free survival,regional relapse-free survival,and distant metastasis-free survival among the ENPG-treated patients was similar to that among the IMRT-treated patients(100%vs.99.1%,100%vs.97.7%,100%vs.99.0%,100%vs.97.4%,respectively,P>0.05).In addition,compared with IMRT,ENPG was associated with decreased total medical costs($4090.42±1502.65 vs.$12620.88±4242.65,P<0.001)and improved QOL scores including dry mouth(3.3±10.5 vs.34.4±25.8,P<0.001)and sticky saliva(3.3±10.5 vs.32.6±23.3,P<0.001).Conclusions:ENPG alone was associated with promising long-term survival outcomes,low medical costs,and satisfactory QOL and might therefore be an alternative strategy for treating newly diagnosed localized stage I NPC patients who refused radiotherapy.However,the application of ENPG should be prudent,and prospective clinical tri-als were needed to further verify the results.

Diagnostic Significance of Intraoperative Ultrasound Contrast in Evaluating the Resection Degree of Brain Glioma By Transmission Electron Microscopic Examination

Background：Contrast-enhanced ultrasound is a dynamic and continuous modality providing real-time view of vascularization and flow distribution patterns of different organs and tumors.In order to evaluate the diagnostic significance of intraoperative contrast-enhanced ultrasound in assessing the resection degree of brain glioma by transmission electron microscopic （TEM） examination,it is important to have specific knowledge about contrast-enhanced ultrasound.Methods：Ultrasound contrast was applied in operations of 120 cases of brain glioma,to evaluate the degree of tumor resection.Biopsy tissues were obtained the suspicious residual tumors surrounding the tumor cavity.The sensitivity and specificity of the residual tumors were determined by the intraoperative ultrasound contrast according to TEM examination results.Results：There were 44 cases of low-grade gliomas and 76 cases of high-grade gliomas.Three hundred and sixty biopsy tissues were obtained.The sensitivity of intraoperative ultrasound contrast in diagnosing the residual tumor was 62.2%,while the specificity degree of it was 92.8%.The consistency coefficient of the ultrasound contrast diagnosis and TEM examination results was 0.584 （Kappa =0.584）,which was between 0.4 and 0.6,therefore it was of medium consistency.Conclusions：Intraoperative ultrasound contrast was of a high sensitivity and specificity in evaluating the excision degree of tumor.The consistency of the residual tumor rate detected,respectively,by ultrasound contrast and TEM examination was of medium consistency.The application of intraoperative ultrasound contrast can improve the resection rate of brain glioma.

Performance of the PRISM I,PIM2,PELOD-2 and PRISM IV scoring systems in western China:a multicenter prospective study

Background The aim of this study was to evaluate the performance of the four scoring tools in predicting mortality in pediatric intensive care units(PICUs)in western China.Methods This was a multicenter,prospective,cohort study conducted in six PICUs in western China.The performances of the scoring systems were evaluated based on both discrimination and calibration.Discrimination was assessed by calculating the area under the receiver operating characteristic curve(AUC)for each model.Calibration was measured across defined groups based on mortality risk using the Hosmer-Lemeshow goodness-of-fit test.Results A total of 2034 patients were included in this study,of whom 127(6.2%)died.For the entire cohort,AUCs for Pediatric Risk of Mortality Score(PRISM)I,Pediatric Index of Mortality 2(PIM2),Pediatric Logistic Organ Dysfunction Score-2(PELOD-2)and PRISM IV were 0.88[95%confidence interval(CI)0.85–0.92],0.84(95%CI 0.80–0.88),0.80(95%CI 0.75–0.85),and 0.91(95%CI 0.88–0.94),respectively.The Hosmer-Lemeshow goodness-of-fit Chi-square value was 12.71(P=0.12)for PRISM I,4.70(P=0.79)for PIM2,205.98(P<0.001)for PELOD-2,and 7.50(P=0.48)for PRISM IV[degree of freedom(df)=8].The standardized mortality ratios obtained with the PRISM I,PIM2,PELOD-2,and PRISM IV models were 0.87(95%CI,0.75–1.01),0.97(95%CI,0.85–1.12),1.74(95%CI,1.58–1.92),and 1.05(95%CI,0.92–1.21),respectively.Conclusions PRISM IV performed best and can be used as a prediction tool in PICUs in Western China.However,PRISM IV needs to be further validated in NICUs.