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Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office 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.)

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Distal cholangiocarcinoma is a type of extrahepatic cholangiocarcinoma with high in vasiveness and poor prognosis, and due to its low rate of early detection, most patients are in the advanced stage at the time of diagnosis. In recent years, with the continuous improvement of medical techniques such as interventional treatment, ablation, and photodynamic therapy and further development of drug therapies inclu? ding chemotherapy, targeted therapy, and immunotherapy, the role of non - surgical treatment in the multimodality therapy for distal cholan-giocarcinoma has attracted more and more attention. This article reviews the advances in local treatment and systematic therapy for distal cholangiocarcinoma and summarizes related articles. The analysis shows that local treatment can relieve biliary obstruction, alleviate tumor burden, and improve quality of life, while systemic therapy may inhibit tumor growth, reduce postoperative recurrence, and prolong survival time. An individualized multimodality treatment regimen should be developed based on various non - surgical treatment methods, so as to provide more effective treatment options for patients with unresectable distal cholangiocarcinoma. [ABSTRACT FROM AUTHOR]

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Copyright of Progress in Modern Biomedicine is the property of Publishing House of Progress in Modern Biomedicine 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.)

Aiming at coalbed methane( CBM) well drilling problems of high dip angle and complex stress in the southern margin of the Junggar Basin, the influence of the coal seam dip angle, in-situ stress and building-up (dropping) on wellbore stability were studied based on weak plane theory,and a multi-objective constraint drilling trajectory optimization model was established. The results show that ① the dip angle of coal seam in Changji area is 10°-25° ,and partly reaches 2 5 ° -4 0 ° , which belongs to high steep coal seam. It has the characteristics of strong permeability anisotropy, strong stress anisotropy and strong rock mechanics anisotropy. ② When drilling horizontal well, according to the influence of coal seam dip angle on wellbore stability, it can be divided into working zone, transition zone and inversion zone. It is working zone when dip angle is between 5°and 25°. Drilling along dip direction and strike direction are the safest and most dangerous orientation,respectively. When dip angle reaches 6 5 ° ,it enters inversion zone, drilling along the dip direction and strike direction both become the safest orientation. The greater stress anisotropy, the greater collapse pressure and the smaller orientation range of safety drilling. ③ When drilling along coal seam, drilling along updip direction is proposed if the dip angle is less than 35°; drilling along down-dip direction is proposed if the dip angle is more than 65°; the wellbore safety is the lowest in the range of 3 5 ° -6 5 ° , then drilling along trend direction is proposed. It is the most dangerous building up (drop) section when the inclination angle is between 45° and 65°,building- up ( dropping) in coal seam should be avoided. ④ In order to reduce the collapse pressure from the landing point to the first target, S-type and J-type drilling trajectory types are proposed,the comparison results show that the trajectory designed in new method is shorter, less friction and torque than the trajectory' designed in conventional method. [ABSTRACT FROM AUTHOR]

In order to solve the optimization problem of horizontal well orientation and layer selection in low-rank thick coal seam,based on low-rank coal stress sensitivity mechanism and horizontal well gas production model with multiple oblique fractures,the influence of horizontal stress difference and fracture on horizontal well orientation are studied quantitatively.Through weak plane theory and fracture mechanics,the wellbore stability calculation model of coalbed methane (CBM) well is established,the comprehensive selection method of geologic logging and fragility index for thick coal seam is put forward.The research shows that:① the coal compression coefficient in southern Qinshui basin is 0.038-0.077,the coal compression coefficient in eastern Ordos basin is 0.025-0.074,the compression coefficient of low-rank coal is greater than that of high-rank coal,the compression coefficient of wet coal sample is greater than that of dry coal sample;when pressure rises,the compressibility coefficient is larger than that of depressurization,the decreasing range of crack sample is greater than that of natural sample.② The horizontal stress difference would lead to permeability anisotropy.The compression coefficient and horizontal stress difference are the two most important impact factors of horizontal well orientation,when horizontal stress difference is greater than 8 MPa in low-rank coal seam or 14 MPa in high-rank coal seam,the optimal orientation is approximately parallel to the direction of minimum horizontal stress.Gas production is optimal when the angle between wellbore and fracture is greater than 60°,the sensitivity of gas production on fracture width decreases significantly when fracture width is greater than 3 mm.③ When face cleat dip angle is less than 25°,drilling along dip direction and strike direction are the maximum and minimum safe drilling fluid density window,respectively.When face cleat dip angle is greater than 25°,drilling along dip direction is still the maximum safe drilling fluid density window,but the minimum safe drilling fluid density window is between dip direction and strike direction.④ The optimal horizontal well orientation in Jiergalangtu area is NE90°-114°,the gas production of well JM-X indicates the method could guide the layer selection of thick coal seams effectively. [ABSTRACT FROM AUTHOR]

In order to study the stress sensitivity mechanism of low-rank coal, the dual media stress sensitivity model and gas production forecast model were established. Based on the stress sensitivity experiment and numerical simulation, the influence of stress sensitivity on the gas production of high and low rank coal were discussed.This research show that：The stress sensitivity is related to the microstructure, mechanical parameters and compression property. The smaller the elastic modulus and the greater the fracture compressibility coefficient, the greater the stress sensitivity. The stress sensitivity of coal with fracture is greater than that of coal without fracture. Multiple increase and decrease of pressure would irreversibly reduce permeability. Discontinuous drainage would cause pressure fluctuation. The gas production is lower than that when the drainage is continuous, the greater the stress sensitive, the greater effect on gas production. The effect of stress sensitive on gas production in Huolinhe area is greater than that in Fan Zhuang area. Due to the characteristic of thick coal and strong stress sensitive, the multistaged indirect fracturing technique and staged fracturing in type “L” horizontal well in roof could be applied to reduce stress sensitivity and improve permeability and gas production. [ABSTRACT FROM AUTHOR]