Results 41 to 50 of about 5,144,321 (345)

Wellbore stability analysis of layered shale based on the modified Mogi–Coulomb criterion

Petroleum, 2020
Borehole instability was frequently encountered during shale gas drilling. Most conventional models are not applicable to layered formation's wellbore stability analysis on account of anisotropic strength characteristic.
Xu Yang, Xiangchao Shi, Yingfeng Meng, Xiaoyong Xie   +3 more
doaj   +1 more source

Collapse Pressure Prediction for Marine Shale Wellbores Considering Drilling Fluid Invasion-Induced Strength Degradation: A Bedding Plane Slip Model

Eng
The stability of deep marine shale wellbores is influenced by both bedding anisotropy and drilling fluid intrusion. Existing models fail to adequately account for the coupled effects of intrusion depth and strength degradation.
Zhilei Zhang, Chunping Li, Yuan Geng, Baohua Yu, Sicong Meng, Lihui Wang   +5 more
doaj   +1 more source

Negative Pressure and Naked Singularities in Spherical Gravitational Collapse [PDF]

, 1996
Assuming the weak energy condition, we study the nature of the non-central shell-focussing singularity which can form in the gravitational collapse of a spherical compact object in classical general relativity.
Clarke C J S, Cooperstock F I, Dwivedi I H, F I Cooperstock, Jhingan S, Joshi P S, Lifshitz E M, P S Joshi, Podurets M A, S Jhingan, Singh T P, T P Singh, Wald R M, Wald R M   +13 more
core   +3 more sources

A numerical model for cloud cavitation based on bubble cluster

Theoretical and Applied Mechanics Letters, 2017
The cavitation cloud of different internal structures results in different collapse pressures owing to the interaction among bubbles. The internal structure of cloud cavitation is required to accurately predict collapse pressure.
Tezhuan Du, Yiwei Wang, Chenguang Huang, Lijuan Liao   +3 more
doaj   +1 more source

Calculation of safe drilling mud density window for shale formation by considering chemo-poro-mechanical coupling effect

Petroleum Exploration and Development, 2019
It is difficult to define safe drilling mud density window for shale sections. To solve this problem, the general Biot effective stress principle developed by Heidug and Wong was modified.
Shifeng ZHANG, Haige WANG, Zhengsong QIU, Wenke CAO, Hongchun HUANG, Zhixue CHEN   +5 more
doaj   +1 more source

Human jugular vein collapse in the upright posture: implications for postural intracranial pressure regulation

Fluids and Barriers of the CNS, 2017
BackgroundIntracranial pressure (ICP) is directly related to cranial dural venous pressure (Pdural). In the upright posture, Pdural is affected by the collapse of the internal jugular veins (IJVs) but this regulation of the venous pressure has not been ...
P. Holmlund, E. Johansson, S. Qvarlander, A. Wåhlin, K. Ambarki, L. Koskinen, J. Malm, A. Eklund   +7 more
semanticscholar   +1 more source

Through-wall yield collapse pressure of casing based on unified strength theory

Petroleum Exploration and Development, 2016
The unified algorithm of through-wall yield collapse pressure for casing with due consideration of strength differential (SD), yield-to-tensile strength ratio, material hardening and intermediate principal stress, which is suitable to calculate collapse ...
Yuanhua LIN, Kuanhai DENG, Yongxing SUN, Dezhi ZENG, Tianguo XIA   +4 more
doaj   +1 more source

Collapse Potential of Loess under Unloading Effect

Advances in Civil Engineering, 2021
Collapsible loess is generally characterized by a sudden and substantial decrease in volume that occurs when is applied under constant stress. To evaluate the loess collapse potential, the self-weight collapse and collapse coefficients have been defined ...
Xin Jin, Tie-Hang Wang, Zai-Kun Zhao, Liang Zhang, Yan-Zhou Hao   +4 more
doaj   +1 more source

Cloud cavitation : observations, calculations and shock waves [PDF]

, 1998
A recent significant advance in our understanding of cavitating flows is the importance of the interactions between bubbles in determining the coherent motions, dynamic and acoustic, of the bubbles in a cavitating flow.
Brennen, Christopher E.
core   +1 more source

Factors Affecting Optimal Titration Pressure of Continuous Positive Airway Pressure Device in Patients with Obstructive Sleep Apnea Syndrome

Turkish Archives of Otorhinolaryngology, 2020
Objective: To assess the effects of anatomical, clinical parameters, and pulmonary respiratory function on the therapeutic titration pressure of continuous positive airway pressure (CPAP) device in obstructive sleep apnea syndrome (OSAS).Methods: The ...
Tolga Kırgezen, Suat Bilici, Mustafa Çakır, Özlem Ceyran, Moustafa Chasan, Özgür Yiğit   +5 more
doaj   +1 more source