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This study focuses on the transportation of non-uniform cuttings in the drilling process of long-reach horizontal wells, conducting a comprehensive theoretical analysis and experimental investigation. Initially, a computational model was established to analyze the influence of cuttings size distribution, fluid dynamics parameters, and wellbore geometry on the transport of non-uniform cuttings. The research elucidates the non-linear relationship between cuttings transport efficiency and parameters such as flow velocity, well inclination, and drill pipe rotation rate in long-reach horizontal wells. It also identifies the existence of a critical flow velocity, beyond which drilling fluid can effectively carry cuttings, preventing their accumulation at the well bottom, and ensuring wellbore cleanliness. Additionally, the paper proposes optimization strategies for wellbore cleaning based on the transport behavior of cuttings, including adjustments to fluid flow velocity and optimization of well inclination, aimed at enhancing drilling efficiency and reducing drilling costs. The findings provide theoretical guidance for cuttings management in long-reach horizontal wells, contributing to improved safety and cost-effectiveness in drilling operations. They hold significant value for advancing the technology of drilling horizontal wells under complex geological conditions.
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http://dx.doi.org/10.1038/s41598-025-05252-1 | DOI Listing |
Water Res
August 2025
Institute for Sustainable Futures, University of Technology Sydney, Ultimo, NSW 2007, Australia.
Over 41 million people in urban Indonesia self-supply drinking water from private wells. However, unsealed on-site sanitation systems (OSSs) located near these groundwater sources raise concerns about fecal contamination. While previous research has discussed on-site sanitation system (OSS)-related risks, limited studies have quantitatively examined how lateral and vertical distance between OSS and groundwater sources influence contamination risk using a clear source-pathway-receptor model.
View Article and Find Full Text PDFACS Omega
August 2025
School of Petrochemical Engineering Environment, Zhejiang Ocean University, Zhoushan, Zhejiang 306022, China.
Horizontal well technology has emerged as a key approach in oil and gas development, particularly for addressing sand production and water breakthrough in offshore reservoirs. To improve the design and efficiency of gravel packing in water control completions, a novel two-dimensional, time-dependent numerical model is developed to simulate slurry flow behavior in horizontal sections. The model accounts for the coupled flow in the screen-wellbore and screen-base pipe annuli, incorporating governing equations for momentum, mass conservation, formation filtration, and gravel settling.
View Article and Find Full Text PDFACS Omega
August 2025
School of Petroleum Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, China.
Multistage fracturing technology for horizontal wells has become a core technology for the effective development of shale and other unconventional oil and gas resources. Following the fracturing and modification of horizontal wells, reliable monitoring of the fracturing effect of each interval, the return of drainage, and the fluid production profile during subsequent production is an important prerequisite for further optimization of the fracturing program and sustainable and effective development. The use of coated tracer sand allows the fracturing effect of horizontal good segments to be assessed and the fluid production profile of horizontal wells to be evaluated in real-time during production.
View Article and Find Full Text PDFSensors (Basel)
July 2025
College of Geophysics and Petroleum Resources, Yangtze University, Wuhan 430100, China.
Gas-water two-phase flow in horizontal and inclined wells is significantly influenced by gravitational forces and spatial asymmetry around the wellbore, resulting in complex and variable flow patterns. Accurate measurement of water holdup is essential for analyzing phase distribution and understanding multiphase flow behavior. Water holdup imaging provides a valuable means for visualizing the spatial distribution and proportion of gas and water phases within the wellbore.
View Article and Find Full Text PDFJ Contam Hydrol
July 2025
Department of Civil and Environmental Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 05006, Republic of Korea. Electronic address:
Climate-induced changes in dissolved organic matter (DOM) and trace organic contaminants (TrOCs) present growing challenges for drinking water treatment, particularly in surface water-dependent regions. Bank filtration (BF), a natural subsurface treatment process, offers a sustainable solution, but its performance and scalability require further validation. This study simultaneously assesses the performance of laboratory-scale and full-scale BF systems using a horizontal collector well (HCW), both receiving the same source water and aquifer materials, to remove DOM and TrOCs, and to investigate changes in microbial communities under equivalent residence times (20 days).
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