Wellbore stability has been considered as a major issue in troubled shale, salt, poorly consolidated sandstone and fractured formations. Thermally induced stresses may be detrimental to a well integrity or enhance the stability depending on if the temperature rises or declines near a wellbore. A cooler fluid is normally injected through a well into a hot formation for thermal energy extraction. A tangential stress reduction is expected near a wellbore due to a temperature decrease and such a reduction is also associated to a hydraulic fracturing process. This seems to suggest a low risk of wellbore stability should expected in the aforementioned situations. A hydraulic fracturing process, however, corresponds to a higher principal stress difference near a wellbore if we express the principal stresses in terms of Mohr stress circles, and such a stress circle however is under a low shear stress limit region at the same time. This stressing states impose a so-called passive loading mode near a wellbore during fracturing, and a stability problem can be expected after fracturing during production.

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