Analysis of Present-day In-situ Stress Difference and Its Influencing Factors Between Two Limbs of Panguan Syncline in Western Guizhou Region
The development characteristics and distribution pattern of present-day in-situ stress indicate important guiding significance for efficient coalbed methane development.Faults,folds and other structures can significantly influence and control the distribution of in-situ stress.The present-day in-situ stress field may also vary within different parts of a single fold.In this study,the Panguan syncline in western Guizhou was taken as an example.Firstly,based on the injection/falloff well test data,the present-day in-situ stresses at different measured points were calculated.Then,based on logging data and the modified Anderson model,the magnitudes of present-day in-situ stress in two wings of Panguan syncline are calculated to release in-situ stress difference in different parts of Panguan syncline.In addition,the effects of geological structure and rock mechanics parameters on the in-situ stress difference between the two wings of Panguan syncline are comprehensively analyzed.It is found that the regional in-situ stress is positively correlated with rock Young's moduli,and negatively correlated with the number and scale of faults within the study area.At the same burial depth,the larger in the in-situ stress magnitude,the lower the permeability.The in-situ stress mechanism affects the permeability as well.The normal faulting stress mechanism is much more favorable to permeability improvement than the reverse faulting stress mechanism.The research results can provide basic geological parameters for the exploration and development of coalbed methane in the Panguan syncline.
present-day in-situ stressinfluencing factorsPanguan synclinecoal permeabilitywestern Guizhou region
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