Results 71 to 80 of about 235,356 (289)

Proportional-Derivative Control of Stick-Slip Oscillations in Drill-Strings

open access: yesMATEC Web of Conferences, 2018
Stick-slip oscillation in drill-string is a universal phenomenon in oil and gas drilling. It could lead to the wear of drill bit, even cause catastrophic failure of drill-strings and measurement equipment.
Lin Wei, Liu Yang
doaj   +1 more source

Colden String Quartet, October 17, 1980

open access: yes, 2019
Recorded during a live performance at Oakland Recital Hall, Western Michigan University, Kalamazoo, Michigan on Oct. 17, 1980, 8:00 p.m., program no. 27 of the School of Music's 1980-1981 season.Colden String Quartet (Marshall Meade and Mary Ann Sabato ...
Colden String Quartet
core  

Research Progress of Three‐Terminal Perovskite/Silicon Tandem Solar Cells Based on Back‐Contact Silicon

open access: yesENERGY &ENVIRONMENTAL MATERIALS, EarlyView.
Perovskite/silicon tandem solar cells offer efficiencies beyond 30%, yet conventional architectures face trade‐offs between optical performance and current matching. Three‐terminal tandems employing silicon back‐contact bottom cells eliminate the current‐matching constraint while minimizing optical losses, offering superior energy yield under real ...
Yunhao Fan   +4 more
wiley   +1 more source

Nonlinear Model and Qualitative Analysis for Coupled Axial/Torsional Vibrations of Drill String

open access: yesShock and Vibration, 2016
A nonlinear dynamics model and qualitative analysis are presented to study the key effective factors for coupled axial/torsional vibrations of a drill string, which is described as a simplified, equivalent, flexible shell under axial rotation.
Fushen Ren   +4 more
doaj   +1 more source

Drill string enclosure

open access: yes, 1992
This invention is comprised of a drill string enclosure which consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts.
Wiersholm, O.   +3 more
core  

Study on Fluid Pressure in Tubing, Dynamic Stress in Reservoir, and Fracture Propagation Morphology During Variable‐Rate Hydraulic Fracturing

open access: yesEnergy Science &Engineering, EarlyView.
Variable‐rate hydraulic fracturing can induce unsteady flow in the tubing, thereby generating fluctuating fluid pressure near the bottom‐hole reservoir. Dynamic stress is generated in the reservoir under the action of fluctuating fluid pressure and propagates as stress waves.
Zhu Ge, Wang Chaojing, Li Weicheng
wiley   +1 more source

Permian Large Igneous Provinces and Their Paleoenvironmental Effects

open access: yesGeophysical Monograph Series, Page 417-434., 2021

Exploring the links between Large Igneous Provinces and dramatic environmental impact

An emerging consensus suggests that Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) are a significant driver of dramatic global environmental and biological changes, including mass extinctions.
Jun Chen, Yi‐Gang Xu
wiley  

+1 more source

An integrated model for drill-string dynamics

open access: yes, 1999
The vibrational states experienced by the active components of a drilling assembly such as that found in the oil or gas industry are discussed in the context of an integrated mathematical model. The work is motivated by the need to understand the complex
Wang, Charles, Tucker, Robin
core   +4 more sources

Research and Application of Drill-String Conveyed Magnetic Ranging Technology in Underground Gas Storage Wells

open access: yesShiyou jixie
In response to the demand for plugging old wells of CO2 gas storage under the carbon peak and carbon neutrality goals, to address the challenges of deploying wireline logging tools to the bottomhole of highly-deviated and complex-structure wells during ...
Ren Xianke   +6 more
doaj   +3 more sources

Drill String Drag and Torque Test Device Design

open access: yesShiyou jixie, 2019
The existing drag and torque theoretical model has many assumptions, leading to a large difference between the calculated value and the true value, which seriously restricts the study of the mechanical behavior of the drill string and the optimization of
吴泽兵   +4 more
doaj  

Home - About - Disclaimer - Privacy