scholarly journals 3D In Situ Stress Estimation by Inverse Analysis of Tectonic Strains

2021 ◽  
Vol 11 (11) ◽  
pp. 5284
Author(s):  
Mingwei Guo ◽  
Shunde Yin ◽  
Chunguang Li ◽  
Shuilin Wang
Keyword(s):  
Inverse Analysis ◽  
In Situ Stress ◽  
New Approach ◽  
Displacement Boundary ◽  
Stress Estimation ◽  
Displacement Based ◽  
In Situ Stress Field ◽  
Traditional Approaches

The determination of a 3D engineering-scale in situ stress field is essential in underground rock mechanics and engineering. The inverse analysis method is a useful technique to determine the in situ stress around the zone of interest. This paper presents a new approach with tectonic strains based on traditional stress-based or displacement-based inverse analysis. In this approach, there are only six tectonic strain variables at the boundary to be optimized, which does not need to select the stress or displacement boundary conditions as the traditional inverse analysis. Therefore, the proposed approach has a better clarity. The proposed approach is applied to the determination of the engineering-scale in situ stress of the underground powerhouses of the Three Gorges Project, and the results are compared with those obtained by traditional approaches. The comparison further shows that the proposed method has better accuracy than traditional methods.

Inverse Analysis of Regional In Situ Stress Prediction Based on Multi-Points Measurement and BP Neural Network

2014 ◽  
Vol 510 ◽  
pp. 226-231 ◽  
Author(s):  
Wei Qun Liu ◽  
Ting Song ◽  
Yu Shou Li ◽  
Shu Fei Zheng ◽  
Jing Yang
Keyword(s):  
Neural Network ◽  
Stress Field ◽  
In Situ Stress ◽  
Engineering Problem ◽  
Regional Stress ◽  
Geological Conditions ◽  
Stress Prediction ◽  
Stress Estimation ◽  
In Situ Stress Field

Based on the measurement of in-situ stress and engineering-geological conditions, we built computing models with pre-exerting boundary loads and simulated the regional stress field involved. Boundary loads can be approximately determined by use of the multiple linear regressions, and be further optimized with the artificial neural network. By calculation, the corresponding initial in-situ stress field can reach ideal accuracy. As an example, we inversely analyzed an engineering problem in Chinese Wo-bei mine. The results shows that the simulation can meet the point measurement very well, and the regional-stress estimation may play an important role in engineering.

MICROSTRUCTURAL AND GEOMECHANICAL CHARACTERISATION OF FAULT ROCKS FROM THE CARNARVON AND OTWAY BASINS

2002 ◽  
Vol 42 (1) ◽  
pp. 167 ◽  
Author(s):  
D.N. Dewhurst ◽  
R.M. Jones ◽  
R.R. Hillis ◽  
S.D. Mildren
Keyword(s):  
Stress Field ◽  
In Situ Stress ◽  
Fault Rocks ◽  
Constant Friction ◽  
Failure Envelopes ◽  
In Situ Stress Field ◽  
Host Reservoir ◽  
Field Failure

The results of natural and laboratory-induced fault behaviour from wells in the Otway Basin are compared with sample material from a producing Carnarvon Basin field where rocks from a fault zone have been cored. Capillary pressure, microstructural and juxtaposition data obtained from these fault rocks indicate a capability to hold back gas columns in excess of 100 m, yet many fault closures are found to contain only palaeo-columns. Trap failure is usually attributed to reactivation of trap-bounding faults, often during Miocene-Recent times in these basins. Faults susceptible to reactivation can be predicted by geomechanical methods involving the determination of the in-situ stress field and the orientation and dip of faults with respect to that stress field. Failure envelopes of fault rocks have been determined to estimate reactivation potential in the present day in-situ stress field. This approach works well where fault rocks are weaker than the host reservoir sandstone, but may not be applicable where fault rocks are stronger. In fields where the latter is the case, intact hydrocarbon columns are present, irrespective of whether faults are optimally oriented for reactivation. This indicates that the assumptions of zero cohesive strength and constant friction coefficient for predicting the reactivation potential of fault rocks may not be completely reliable.

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