The exploitation of oil resources has now extended to ultra-deep formations,with depths even exceeding 10,000 m.During drilling operations,the bottomhole temperature(BHT)can surpass 240℃.Under such high-temperature c...The exploitation of oil resources has now extended to ultra-deep formations,with depths even exceeding 10,000 m.During drilling operations,the bottomhole temperature(BHT)can surpass 240℃.Under such high-temperature conditions,measurement while drilling(MWD)instruments are highly likely to malfunction due to the inadequate temperature resistance of their electronic components.As a wellbore temperature control approach,the application of thermal insulated drill pipe(TIDP)has been proposed to manage the wellbore temperature in ultra-deep wells.This paper developed a temperature field model for ultra-deep wells by coupling the interactions of multiple factors on the wellbore temperature.For the first time,five distinct TIDP deployment methods were proposed,and their corresponding wellbo re temperature variation characte ristics were investigated,and the heat transfer laws of the ultra-deep wellbore-formation system were quantitatively elucidated.The results revealed that TIDP can effectively restrain the rapid rise in the temperature of the drilling fluid inside the drill string by reducing the heat flux of the drill string.Among the five deployment methods,the method of deploying TIDP from the bottomhole upwards exhibits the best performance.For a 12,000 m simulated well,when6000 m of TIDP are deployed from the bottomhole upwards,the BHT decreases by 52℃,while the outlet temperature increases by merely 1℃.This not only achieves the objective of wellbore temperature control but also keeps the temperature of the drilling fluid at the outlet of annulus at a relatively low level,thereby reducing the requirements for the heat exchange equipment on the ground.The novel findings of this study provide significant guidance for wellbore temperature control in ultra-deep and ultra-high-temperature wells.展开更多
“High nutrient, low chlorophyll (HNLC)” regions were created by locking iron into sedimentary iron sulfides with hydrogen sulfide available from volcanic eruptions in surrounding oceans. Appropriate locations and de...“High nutrient, low chlorophyll (HNLC)” regions were created by locking iron into sedimentary iron sulfides with hydrogen sulfide available from volcanic eruptions in surrounding oceans. Appropriate locations and deployment methods for the iron fertilization were far from volcanoes, earthquakes and boundaries of tectonic plates to reduce the chance of iron-locking by volcanic sulfur compounds. The appropriate locations for the large-scale iron fertilization are proposed as Shag Rocks in South Georgia and the Bransfield Strait in Drake Passage in the Southern Ocean due to their high momentum flux causing efficient iron deployment. The iron (Fe) replete compounds, consisting of natural clay, volcanic ash, agar, N<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">-fixing mucilaginous cyanobacteria, carbon black, biodegradable plastic foamed polylactic acid, fine wood chip, and iron-reducing marine bacterium, are deployed in the ocean to stay within a surface depth of 100<span style="font-family:""> <span style="font-size:12px;font-family:Verdana;"><span style="font-size:12px;font-family:Verdana;"><span style="font-family:Verdana;font-size:12px;">m for phytoplankton digestion. The deployment method of Fe-replete composite with a duration of at least several years for the successful iron fertilization, is configured to be on the streamline of the Antarctic Circumpolar Current (ACC). This will result in high momentum flux for its efficient dispersion on the ocean surface where diatom, copepods, krill and humpback whale stay together (~100<span style="font-family:""> <span style="font-family:""><span style="font-size:12px;font-family:Verdana;">m). Humpback whales are proposed as a biomarker for the successful iron fertilization in large-scale since humpback whales feed on krill, which in turn feed on cockpods and diatoms. The successful large-scale iron fertilization may be indicated by the return of the humpback whales if they could not be found for a long period before the iron fertilization. On-line monitoring for the successful iron fertilization focuses on the simultaneous changes of the following two groups;the increase concentration group (chlorophyll, O<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">, Dissolved Oxygen (DO), Di Methyl Sulfide (DMS)) and the decrease concentration group (nitrate, phosphate, silicate, CO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">, Dissolved CO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;"> (DCO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">)). The monitoring of chlorophyll-<span style="font-size:12px;font-family:Verdana;">a<span style="font-size:12px;font-family:Verdana;">, nitrate phosphate, and silicate concentrations after deploying the Fe-replete complex is carried out throughout the day and night for the accurate measurement of algal blooms.展开更多
Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve...Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve these problems,an arbitrarily adjustable camera module deployment method and the corresponding automatic image acquisition equipment with multi-area array cameras are proposed and developed.Such method enables the acquisition of full-length surface images of the hydraulic tunnels with different cross-section forms and diameters by a one-way travel,and the overlap rate and accuracy of the acquired image sets meet the requirements of three-dimensional reconstruction and panoramic image generation.In addition,to improve the speed and accuracy of traditional algorithms for tunnel surface defects detection,this paper proposes an improved YOLOv5s-DECA model.The algorithm introduces DenseNet to optimize the backbone feature extraction network and incorporates an efficient channel attention ECA module to make a better extraction of features of defects.The experimental results show that mAP,and F1-score of YOLOv5-DECA are 73.4%and 74.6%,respectively,which are better than the common model in terms of accuracy and robustness.The proposed YOLOv5-DECA has great detection performance for targets with variable shapes and can solve the problem of classification imbalance in surface defects.Then,by combining YOLOv5-DECA with the direction search algorithm,a“point-ring-section”method is established to allow rapid identification of common surface defects by detecting them layer by layer with the bottom image of the stitched panorama as the seed.The presented method in this paper effectively solves the problem that a single image fails to show the overall distribution of the defects and their accurate positioning in a whole large tunnel section and the effective features of defects in an excessively large panoramic image size are difficult to be captured by the neural network.Field applications demonstrated that the presented method is adequate for high-precision and intelligent surface defect detection and positioning for different small-section hydraulic tunnels such as circular,arch-wall,and box-shaped hydraulic tunnels.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U22B2072)Research Project of China Petroleum Science and Technology Innovation Fund(Grant No.2025DQ02-0144)。
文摘The exploitation of oil resources has now extended to ultra-deep formations,with depths even exceeding 10,000 m.During drilling operations,the bottomhole temperature(BHT)can surpass 240℃.Under such high-temperature conditions,measurement while drilling(MWD)instruments are highly likely to malfunction due to the inadequate temperature resistance of their electronic components.As a wellbore temperature control approach,the application of thermal insulated drill pipe(TIDP)has been proposed to manage the wellbore temperature in ultra-deep wells.This paper developed a temperature field model for ultra-deep wells by coupling the interactions of multiple factors on the wellbore temperature.For the first time,five distinct TIDP deployment methods were proposed,and their corresponding wellbo re temperature variation characte ristics were investigated,and the heat transfer laws of the ultra-deep wellbore-formation system were quantitatively elucidated.The results revealed that TIDP can effectively restrain the rapid rise in the temperature of the drilling fluid inside the drill string by reducing the heat flux of the drill string.Among the five deployment methods,the method of deploying TIDP from the bottomhole upwards exhibits the best performance.For a 12,000 m simulated well,when6000 m of TIDP are deployed from the bottomhole upwards,the BHT decreases by 52℃,while the outlet temperature increases by merely 1℃.This not only achieves the objective of wellbore temperature control but also keeps the temperature of the drilling fluid at the outlet of annulus at a relatively low level,thereby reducing the requirements for the heat exchange equipment on the ground.The novel findings of this study provide significant guidance for wellbore temperature control in ultra-deep and ultra-high-temperature wells.
文摘“High nutrient, low chlorophyll (HNLC)” regions were created by locking iron into sedimentary iron sulfides with hydrogen sulfide available from volcanic eruptions in surrounding oceans. Appropriate locations and deployment methods for the iron fertilization were far from volcanoes, earthquakes and boundaries of tectonic plates to reduce the chance of iron-locking by volcanic sulfur compounds. The appropriate locations for the large-scale iron fertilization are proposed as Shag Rocks in South Georgia and the Bransfield Strait in Drake Passage in the Southern Ocean due to their high momentum flux causing efficient iron deployment. The iron (Fe) replete compounds, consisting of natural clay, volcanic ash, agar, N<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">-fixing mucilaginous cyanobacteria, carbon black, biodegradable plastic foamed polylactic acid, fine wood chip, and iron-reducing marine bacterium, are deployed in the ocean to stay within a surface depth of 100<span style="font-family:""> <span style="font-size:12px;font-family:Verdana;"><span style="font-size:12px;font-family:Verdana;"><span style="font-family:Verdana;font-size:12px;">m for phytoplankton digestion. The deployment method of Fe-replete composite with a duration of at least several years for the successful iron fertilization, is configured to be on the streamline of the Antarctic Circumpolar Current (ACC). This will result in high momentum flux for its efficient dispersion on the ocean surface where diatom, copepods, krill and humpback whale stay together (~100<span style="font-family:""> <span style="font-family:""><span style="font-size:12px;font-family:Verdana;">m). Humpback whales are proposed as a biomarker for the successful iron fertilization in large-scale since humpback whales feed on krill, which in turn feed on cockpods and diatoms. The successful large-scale iron fertilization may be indicated by the return of the humpback whales if they could not be found for a long period before the iron fertilization. On-line monitoring for the successful iron fertilization focuses on the simultaneous changes of the following two groups;the increase concentration group (chlorophyll, O<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">, Dissolved Oxygen (DO), Di Methyl Sulfide (DMS)) and the decrease concentration group (nitrate, phosphate, silicate, CO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">, Dissolved CO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;"> (DCO<sub><span style="font-size:12px;font-family:Verdana;">2</sub><span style="font-size:12px;font-family:Verdana;">)). The monitoring of chlorophyll-<span style="font-size:12px;font-family:Verdana;">a<span style="font-size:12px;font-family:Verdana;">, nitrate phosphate, and silicate concentrations after deploying the Fe-replete complex is carried out throughout the day and night for the accurate measurement of algal blooms.
基金funded by the Hunan Provincial Natural Science Foundation Project(Grant No.2023JJ30672)the Science and Technology Research and Development Program Project of China Railway Group Limited(Grant No.2021-Special-08(A))+1 种基金the Science and Technology Research and Development Plan Project of China National Railway Group Co.Ltd.(Grant No.L2022G003)the Open Foundation of National Engineering Laboratory for High-speed Railway Construction(No.HSR202005).
文摘Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve these problems,an arbitrarily adjustable camera module deployment method and the corresponding automatic image acquisition equipment with multi-area array cameras are proposed and developed.Such method enables the acquisition of full-length surface images of the hydraulic tunnels with different cross-section forms and diameters by a one-way travel,and the overlap rate and accuracy of the acquired image sets meet the requirements of three-dimensional reconstruction and panoramic image generation.In addition,to improve the speed and accuracy of traditional algorithms for tunnel surface defects detection,this paper proposes an improved YOLOv5s-DECA model.The algorithm introduces DenseNet to optimize the backbone feature extraction network and incorporates an efficient channel attention ECA module to make a better extraction of features of defects.The experimental results show that mAP,and F1-score of YOLOv5-DECA are 73.4%and 74.6%,respectively,which are better than the common model in terms of accuracy and robustness.The proposed YOLOv5-DECA has great detection performance for targets with variable shapes and can solve the problem of classification imbalance in surface defects.Then,by combining YOLOv5-DECA with the direction search algorithm,a“point-ring-section”method is established to allow rapid identification of common surface defects by detecting them layer by layer with the bottom image of the stitched panorama as the seed.The presented method in this paper effectively solves the problem that a single image fails to show the overall distribution of the defects and their accurate positioning in a whole large tunnel section and the effective features of defects in an excessively large panoramic image size are difficult to be captured by the neural network.Field applications demonstrated that the presented method is adequate for high-precision and intelligent surface defect detection and positioning for different small-section hydraulic tunnels such as circular,arch-wall,and box-shaped hydraulic tunnels.
