bluuebunny/crossref_metadata_2025_split huggingface dataset:
Key Technologies for Volume Fracturing of Yingxiongling Shale Oil in the Qaidam Basi
Authors: Wan Youyu , Lin Hai , Xiong Tingsong , Zhang Yuxiang , Liu Shiduo , Wang Zhisheng , Zhao Wenkai , Guo Delong , Xie Guiqi , Feng Daqiang 
Published: November 2024

Abstract
The Yingxiongling shale oil in the Qaidam Basin is the preferred choice for Qinghai Oilfield to enter the field of unconventional oil and gas resources, and volume fracturing is the core technology for shale oil exploration and development. Through the analysis of the geological and engineering characteristics of the Yingxiongling shale oil, it is found that there are difficulties in volume fracturing of the Yingxiongling shale oil, such as frequent changes in vertical mechanical properties and limited vertical control range; large stress differences, making it difficult to form complex artificial fractures; difficulty in opening multiple clusters of perforation holes; high water shortage in the plateau, high mineralization of the formation backflow fluid, and difficulty in reusing the backflow fluid. By iteratively modeling three-dimensional geomechanics, a high-resolution three-dimensional geomechanical model is established to guide the optimization of volume fracturing schemes. Through the integration of geological and engineering selection and clustering, three-stage active control technology for cracks, and the dual temporary plugging process of boreholes and cracks, the targeted and complex degree of artificial crack transformation can be improved. Through the study of high salinity fracturing fluid system, it has been found that high salinity backflow fluid can replace slick water and alleviate the demand for fresh water in volume fracturing. The article analyzes the difficulties of shale oil volume fracturing and studies the formation of an effective set of key techniques for volume fracturing, achieving the goal of improving the degree and effectiveness of transformation, and providing support for the exploration and development of the Yingxiongling shale oil in the Qaidam Basin.
Research and Application of Flexible Fracturing Manifold in Volumetric fracturing
Authors: Chai Long , Bai Mingwei , Ye Sai , Che Haoyang , Yang Min 
Published: November 2024

Abstract
In order to solve the problems of high pressure pipe valves in Volumetrictric fracturing, such as large demand of high pressure pipe and valve parts, high pressure manifold for fracturing complex connection, fracturing pipeline connections are complex, long fracturing construction preparation period. The economy and timeliness of pipeline connection seriously affect the speed and efficiency of Volumetrictric fracturing operations. This paper designed and developed the high pressure flexible composite pipe and carried out its performance evaluation test. Combined with Volumetrictric fracturing operation conditions, supporting functional modular manifold system, overcome flexible pipeline and rigid pipeline fast connection technology, flexible fracturing manifold system was formed. Through the large-scale field application in the unconventional reservoir Volumetric fracturing field, The flexible fracturing manifold is compared with the conventional high-pressure pipe valve connection and the single pipe universal connection, the flexible fracturing manifold can reduce the use of high-pressure pipe valves by 1/3, increase the efficiency of fracturing manifold connection by 50%, and reduce the labor intensity by 50%, enables efficient, reduce high pressure manifold connection points by 70%. The timeliness and safety of fracturing manifold connections have been greatly improved. Flexible fracturing manifold fundamentally change the connection mode of Volumetrictric fracturing high-pressure manifold, and realizes the speed and efficiency of reservoir transformation.
Experimental study on oxidation characteristics of low temperature oxidation stage of thin oil in P layer in eastern Daqing Placanticline
Authors: Wu Yan , Sun Hanpeng 
Published: November 2024

Abstract
The eastern oilfield of Daqing Placanticline belongs to a medium low permeability oilfield as a whole, with some blocks developed earlier and in the stage of high water content and high recovery. The main oil layer is severely flooded, and the remaining oil distribution is scattered. It is difficult to improve the development effect through conventional water flooding adjustments. In order to clarify the feasibility and key parameters of thin oil fire flooding development in the eastern P reservoir of Daqing Placanticline, experimental research on low-temperature oxidation stage oxidation characteristics was conducted using typical block rock cuttings and crude oil. Complete 20 sets of experiments on the oxidation characteristics of crude oil under different temperature and pressure, 4 sets of experiments on the oxidation characteristics of crude oil under different combustion systems, and 12 sets of tests on the composition of crude oil and exhaust gas. Clarify the low-temperature oxidation characteristics of crude oil under different temperatures and pressures, determine the oxidation characteristics of crude oil under different catalytic systems, and divide the temperature range for crude oil to reach ignition, providing theoretical support for improving reservoir fuel for thin oil flooding.
Study on The Areal Sweep Efficiency and Water Breakthrough Time Prediction of Water Flooding in Carbonate Reservoirs
Authors: Na Risu , Zhang Yu , Guo Sheng , Li Changyong , Sun Futing 
Published: November 2024

Abstract
This study concentrates on the evaluation of areal sweep efficiency and the prediction of water breakthrough time in a representative medium-porosity, medium-high permeability thin carbonate reservoir, using the H oilfield in the Middle East as an example. Areal geological models, accounting for variations in high permeability streaks and regional heterogeneity, were established to study the impact of areal heterogeneity on the sweep coefficient and morphology of the water flooding front. The results revealed that areal heterogeneity significantly affects both the areal sweep efficiency and the morphology of the water flooding front. In models with high permeability streaks, a greater permeability ratio led to more uneven displacement in all directions, consequently, this resulted in a poorer overall development effect. Furthermore, regional heterogeneity was found to significantly impact sweep efficiency, the larger the area of relatively low permeability zones, the more severe the reduction in sweep efficiency and the overall injection production effect. A theoretical method for accurately predicting water breakthrough time was established based on the stream tube method. This method was applied to the H oilfield, which reduced the discrepancy between the predicted and actual breakthrough times, thereby confirming its feasibility. The novelty of this study lies in overcoming the limitations of the stream tube method and utilizing numerical simulation to calculate the areal sweep coefficient at the time of water breakthrough. This approach quantitatively characterized the affected streamline area, thereby enhancing the accuracy of water breakthrough time predictions. This research provides significant theoretical insights and practical references for understanding the areal sweep efficiency of thin carbonate reservoirs, predicting water breakthrough times, and optimizing injection production strategies.
Borehole Stability of Natural Gas Hydrate Reservoirs
Authors: Yan Chuanliang , Zhang Zhe , He Yufa , Tian Zheng , Cheng Yuanfang 
Published: November 2024

Abstract
The decomposition of natural gas hydrate (NGH) due to long-term drilling may decrease the strength of reservoirs and increase the borehole failure risk. Meanwhile, the creep properties of NGH reservoirs also may give rise to engineering problems including borehole shrinkage and jamming of drilling tools in the late stage of drilling, which seriously impairs the drilling safety. A thermal-fluid-solid multi-field coupling model considering the decomposition kinetics of NGH and creep properties of reservoirs was established to explore the influence mechanism of NGH decomposition and creep properties of hydrate-bearing sediments on mechanical behaviors of boreholes. In addition, influences of drilling parameters and geomechanical properties of reservoirs on borehole stability in the drilling process of NGH reservoirs were analyzed. Research results show that creep properties of NGH deposits causes homogenization of stress distribution in different directions of NGH reservoirs around boreholes, transition of plastic zones around boreholes to a round shape, and possibly overall borehole collapse. As the horizontal geostress becomes more inhomogeneous, the borehole instability risk increases; the higher the initial pore pressure of formation is, the lower the effective geostress and the lower the borehole instability risk. The research results can provide theoretical support for safe drilling of NGH reservoirs in South China Sea and promote the early commercial exploitation of NGH resources in China.
Improvement of Sonic Logging Porosity Calculation Method in South Sulige Block
Authors: He Wang , Yalan Wang , Bo Wang , Yonghui Jia , Yuan Sun , Xiao Xiang , Kaicheng Yang 
Published: November 2024

Abstract
South Sulige Block is a lithologic gas reservoir with low porosity and permeability, low pressure and low abundance, of which the heterogeneity is very high and pore structure is complex. Due to the influence of lithology and pore structure, the skeleton value is uncertain and it is hard to give a fixed value. It is difficult to obtain the true porosity of formation accurately by using the traditional method of calculating porosity by Wyllie formula in sonic logging. In this paper, according to the principle of sonic logging and rock response characteristics, combined with core analysis data of this area and adjacent areas, using the acoustic time and core analysis porosity regression formula to calculate porosity first, and then, according to different shale content, the corresponding shale correction is carried out for heavy shale content intervals on the basis of core regression formula, which eliminates the porosity calculation error caused by the influence of shale content. Practical application shows that the porosity calculated by this method is in good agreement with the results of core analysis, and can reflect the reservoir characteristics and production capacity of the formation more truly.
Two-stage Cementing Technology for Production Casing in Deep Reservoir of Chenghai Oilfield
Authors: Hu Jinjun , Shi Weiji , Wu Wenbing , Shen Jiyang , Li Jianglong , Shen Yayun 
Published: November 2024

Abstract
The whole well section cementing of production casing in 5 000 m deep reservoir of Chenghai Oilfield was faced with many difficulties, such as long sealing section, large temperature difference, serious leakage and serious cement slurry contamination caused by organic salt drilling fluid. On the basis of the stage cementing technology, the newly developed micro thixotropic cement slurry and anti-organic salt spacer were used to reduce leakage and contamination, and the double-acting stage collar was applied to reduce the risk of stage cementing tool failure. A two-stage cementing technology suitable for the development of deep reservoir in Chenghai Oilfield was formed. The cement slurry exhibits good micro thixotropic performance at 50~130 °C. The rheological properties change from thin to thick and then to thin with increasing temperature, and the difference of static shear force is no less than 12.2 Pa. The spacer shows good anti-contamination property. The thickening time of the contaminated cement slurry after mixing the spacer is more than 6 h, and the sedimentation stability of the spacer is no more than 0.04 g/cm3. The double-acting stage collar has the advantages of both mechanical and differential pressure stage collar, which can effectively reduce the risk of circulation holes not being opened or closed. The technology had been successfully applied in 2 wells in Chenghai Oilfield. During cementing operation, the stage collar worked well, there was no leakage, cement slurry contamination could be controlled, and cementing quality met needs. The technology can be further promoted and applied in the area.
Design and Test of Hydraulic Bottom Seal Fracturing Tool for Coiled Tubing
Authors: Wang Weipeng , Long Shiming , Su Minwen , Ma Yuxin , Huang Weiping 
Published: November 2024

Abstract
As the main tool for reservoir reconstruction of Longdong shale reservoir in Changqing Oilfield, the coiled tubing bottom seal drag-segment fracturing tool is currently in the stage of scale promotion, providing tool support for the efficient development of Longdong shale oil. However, in the process of horizontal construction with large water vertical ratio and super long horizontal section, there are construction problems such as natural depth limitation of the tool and difficulty in setting the bottom packer, which seriously affect the construction efficiency and quality. In view of the above problems, this paper carried out the development of pumped coiled tubing hydraulic bottom seal drag-segment fracturing tool. With the technical ideas of pumping cup deepening and hydraulic setting bottom packer, the hydraulic setting type bottom packer, soluble cup pumping sub and supporting tools were designed and developed. By using the method of annular pumping and tubing accompanying injection, the tail cup pumping sub was used to generate throttle and larger cup outer diameter, forming a large hydraulic traction force to carry the tool string to break the depth limit. Without applying drilling pressure, the bottom packer was set by oil injection and displacement, and the setting state was lifted and lifted after the fracturing construction, providing a reliable tool scheme for solving the above engineering problems. The indoor evaluation results show that the traction effect of the bowl pumping short joint with small displacement of water is good, the bottom packer is smooth in the setting and unpacking action at 120°C, and the sealing is reliable under 70MPa pressure. The overall test of the tool string can realize the setting and unpacking action without the intervention of drill pressure. Six well tests were carried out in the field. The pumping depth was 430m under the condition of 740L/min water pumping displacement, and the oil injection displacement was increased to 550L/min. The hydraulic setting was fast and reliable, which effectively improved the construction capacity of the coiled tubing fracturing tool in the ultra-long horizontal well, greatly shortened the time consumption of interlayer conversion, and improved the speed and efficiency significantly.
Analysis of Fracture Reason of Transmission Shaft of Screw Drilling Tool in a Certain Well
Authors: Hu Fang-ting , Zhao Mi-feng , Geng Hai-long , Long Yan , Lou Er-biao 
Published: November 2024

Abstract
During the drilling process of a certain well in an oil field, the transmission shaft of the screw drilling tool broke. According to research, the screw drilling tool is brand new and has been in use for only 63.5 hours, indicating early failure. The fracture of the transmission shaft of the screw drilling tool is flat and severely worn, and the fracture is located at the change in diameter. In order to analyze the causes of the tool’s failure and avoid similar accidents, this article conducted non-destructive testing, macroscopic fracture analysis, chemical composition analysis, tensile performance testing, Charpy impact testing, Brinell hardness testing, metallographic analysis, microscopic analysis, and a comprehensive analysis of the failed transmission shaft of the spiral drilling rig. Through a series of analyses, it is believed that this tool belongs to fatigue fracture. The main reason is the presence of quenching cracks in the matrix structure near the fracture surface, which does not comply with industry standards. At the same time, before the screw drilling tool was put into use in the well, the operator did not conduct a flaw detection on the transmission shaft body according to the standard, so that quenching cracks were not detected in advance. After entering the well, the transmission shaft undergoes rapid propagation of quenching cracks under variable load, ultimately leading to early fatigue failure. This article suggests that manufacturers optimize the heat treatment process of screw drilling tool transmission shafts to improve product quality and prevent quenching cracks from appearing in the body. At the same time, operators should strictly follow the standards for non-destructive testing to avoid drilling tools with quality issues from entering the well for use.
A Well-Tested Pump Card Classification and Identification Algorithm Based on Time Series Analysis Techniques
Authors: Yang Hao-lin , Wang Jing-xin , Liu Hao , Wang Shuai , Zhang Quan-xin 
Published: November 2024

Abstract
To accurately identify the operational conditions of oil pumping wells, promptly monitor the working status of oil wells, expedite responses to sudden pumping well accidents, and ensure orderly production at the oil extraction site, this paper introduces a time segment-based oil pumping well condition identification algorithm. This method no longer relies on drawn dynamometer cards for condition identification. Instead, it solely utilizes sensor-provided polished rod displacement and load time series, aligning more closely with the data’s intrinsic nature. The algorithm is sufficiently lightweight, highly responsive, and does not require GPU resources, making it suitable for edge deployment. Furthermore, this approach provides evidence of the time continuity and numerical continuity of time series data. Compared to traditional identification methods, this approach maintains a high level of accuracy, offers a streamlined model, and is interpretable, presenting a novel perspective for oil pumping well condition identification.
Research on an aeroengine bearing fault diagnosis method based on WMSST-CNN-BKA-LSSVM
Authors: Wei Zhihui , Liu Zhengang , Guo Zhengbo , Guo Haidong 
Published: November 2024

Abstract
To effectively extract the fault feature from small sample datasets and improve the accuracy of the model, an aeroengine bearing fault diagnosis method is proposed in this research based on wavelet multi-synchrosqueezed transform-convolutional neural network-black-winged kite algorithm-least squares support vector machine (WMSST-CNN-BKA-LSSVM). WMSST was used to perform modal decomposition on the collected fault data to obtain the time-frequency images. The time-frequency images were input into CNN for fault data feature extraction. The results of the CNN fully connected layer were used as input to the LSSVM, and the BKA was used to optimize the key parameters of the LSSVM to classify aeroengine bearing faults. The method was verified by aeroengine bearing test data from the Harbin Institute of Technology. The research showed that the accuracy is 99.86% when the faulty test samples are 70%, and the accuracy is 93.90% when the faulty samples are 30%. The accuracy showed the applicability of this method in small sample fault diagnosis. By comparing the method with a one-dimensional convolutional neural network (1D-CNN) and the convolutional neural network - long short-term memory (CNN-LSTM), it is found that the accuracy has been dramatically improved.
Nonuniform Bose–Einstein condensate: I. An improvement of the Gross–Pitaevskii method
Authors: Tomchenko Maksim 
Published: November 2024

Abstract
A nonuniform condensate is usually described by the Gross–Pitaevskii (GP) equation, which is derived with the help of the c-number ansatz

Ψ
^

(

r

,
t
)
=
Ψ
(

r

,
t
)

. Proceeding from a more accurate operator ansatz

Ψ
^

(

r

,
t
)
=

a
^

0

Ψ
(

r

,
t
)

/

N

, where N is the number of Bose particles, we find the equation

i
ℏ

∂
Ψ
(

r

,
t
)

∂
t

=
−

ℏ

2

2
m

∂

2

Ψ
(

r

,
t
)

∂

r

2

+

(
1
−

1
N

)

2
c
Ψ
(

r

,
t
)

|

Ψ
(

r

,
t
)

|

2

, which we call the GP
N
equation. It differs from the GP equation by the factor

(
1
−
1

/

N
)

. We compare the accuracy of the GP and GP
N
equations by analysing the ground state of a one-dimensional system of point bosons with repulsive interaction (c > 0) and zero boundary conditions. Both equations are solved numerically, and the system energy E and the particle density profile

ρ
(
x
)

are determined for the mean particle density

ρ
¯

=
1

, different values of N and of the coupling constant

γ
=
c

/

ρ
¯

. The solutions are compared with the exact ones obtained by the Bethe ansatz. The results show that the GP and GP
N
equations equally well describe the many-particle system (

N
≳
100

) being in the weak coupling regime (

N

−
2

≪
γ
≲
0.1

). But for the few-boson system (

N
≲
10

) with

γ
≲

N

−
2

the solutions of the GP
N
equation are in much better agreement with the exact ones. Thus, the multiplier

(
1
−
1

/

N
)

allows one to describe few-boson systems with high accuracy. This means that it is reasonable to extend the notion of Bose–Einstein condensation to few-particle systems.
Comprehensive Study of EPDM Rubber Properties: Temperature-Dependent Stiffness, Tensile Behavior and FEA Calibration
Authors: Foltuț Daniel , Vălean Estera , Șoșoi Georgiana-Iulia , Pascal Dragoș-Toader , Pospisil Jan , Buzdugan Monica 
Published: November 2024

Abstract
This work examines the temperature-dependent stiffness of Ethylene Propylene Diene Monomer (EPDM) rubber using tensile testing and Dynamic Mechanical Analysis (DMA). Additionally, it provides an appropriate model for Finite Element Analysis (FEA). The tensile tests indicate that EPDM has high rigidity and minimal elongation at −40°C, intermediate characteristics at 23°C, and a decrease in stiffness with rising temperature, up to 80°C. Nevertheless, a sudden rise in rigidity is seen at a temperature of 125°C, which may be ascribed to the strengthening influence of carbon black. The DMA findings confirm this pattern, demonstrating an upward trend in storage modulus and stiffness as temperature increases. At the same time, tan delta and loss modulus fall, suggesting a reduction in viscoelastic damping. The calibration of the Finite Element Analysis (FEA) model, using the Arruda-Boyce, Yeoh 3D, and Mooney-Rivlin 5-parameter models, determines that the Arruda-Boyce model is the most precise in accurately replicating the experimental data. The results indicate that the improved resistance to heat and increased rigidity of EPDM at high temperatures are affected by its material composition. However, more investigation is required to have a comprehensive understanding of the underlying processes.