气候变化领域集成服务门户(CCPortal): Modified Cam-Clay Model for Large Stress Ranges and Its Predictions for Geological and Drilling Processes

CCPortal

DOI	10.1029/2020JB019500
	Modified Cam-Clay Model for Large Stress Ranges and Its Predictions for Geological and Drilling Processes
	Heidari M.; Nikolinakou M.A.; Flemings P.B.
发表日期	2020
ISSN	21699313
卷号	125 期号:12
英文摘要	We modify the Modified Cam-Clay (MCC) model for large stress ranges encountered in geological applications. The MCC model assumes that the friction angle (ϕ) and the slope of the compression curve (λ) of a mudrock are constant and thus predicts constant values for the lateral effective stress ratio under uniaxial, vertical strain (K0) and undrained strength ratio ((Formula presented.)). However, experimental work shows that λ, ϕ, and (Formula presented.) decrease and K0 increases substantially with stress over large stress ranges (e.g., up to 100 MPa). We incorporate the stress dependency of λ and ϕ into the MCC model and use the new model to predict (Formula presented.) and K0 ratios. The modified model, with only one additional parameter, successfully predicts the stress dependency of these ratios. We encode the modified model and use it for finite-element analysis of a salt basin in the deepwater Gulf of Mexico. The stresses that the new model predicts around salt differ significantly from those predicted using the original model. We incorporate the stress dependency of the friction angle into the analytical models developed for critical tapers, wellbore drilling, and the stability of submarine channel levees. We show that the decrease of the friction angle with stress (1) results in a concave surface for critical wedges, (2) shifts the drilling window to higher mud weights and makes it narrower for a vertical wellbore, and (3) causes deep-seated failure of submarine channel levees at lower angles. Our study could improve in situ stress and pore pressure estimation, wellbore drilling, and quantitative understanding of geological processes. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	compression curve; critical-taper theory; drilling window; friction angle; in situ stresses; Modified Cam-Clay model
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187457
作者单位	Bureau of Economic Geology; Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States; Department of Geological Sciences, and Institute for Geophysics; Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States
推荐引用方式 GB/T 7714	Heidari M.,Nikolinakou M.A.,Flemings P.B.. Modified Cam-Clay Model for Large Stress Ranges and Its Predictions for Geological and Drilling Processes[J],2020,125(12).
APA	Heidari M.,Nikolinakou M.A.,&Flemings P.B..(2020).Modified Cam-Clay Model for Large Stress Ranges and Its Predictions for Geological and Drilling Processes.Journal of Geophysical Research: Solid Earth,125(12).
MLA	Heidari M.,et al."Modified Cam-Clay Model for Large Stress Ranges and Its Predictions for Geological and Drilling Processes".Journal of Geophysical Research: Solid Earth 125.12(2020).