Water migration in shale will be the basement of all wellbore stability designs with chemical-mechanical coupling. A brand new experimental equipment selleck inhibitor to measure in situ water diffusion coefficient of shale is designed on this paper. Along with a sample model to assess time-dependent collapse strain with chemical-mechanical coupling is presented. 2. Experimental Research to the Hydration of ShaleThe no cost water and ion will penetrate into shale below the driving force of chemical prospective and strain difference among the pore fluid and drilling fluid [55�C58]. Water written content of shale modifications by many mechanisms such as osmosis movement, viscous flow and capillary movement. Osmosis movement, driving force is because of chemicals and ions with unique composition in drilling fluid and pore fluid.
In order to assess the hydration of drilling fluid, the coefficient of water absorption and diffusion and the swellingmtor ratio should be determined very first .two.1. Experimental Study around the Water Absorption of Shale2.1.one. Experimental Tools Cherevent let 1 finish face of shale sample make contact with with drilling fluid along with the other end face wrapped up by plastic movie, then he measured the water written content increment in numerous location. But his experiment can only be carried out in area temperature and with zero confining strain. But throughout drilling course of action in deep formation, it can be in the ailment of substantial temperatureEfaproxiral Sodium and substantial pressure. Shale hydration is influenced by temperature and strain critically, so his experimental outcome was inconsistent with actual drilling.
So as to test the coefficient of water diffusion of shale, we developed an in situ check equipment of water diffusion coefficient which may match the downhole temperature and strain affliction when drilling (Figure 1).Figure 1The experimental gear sketch.Technical parameters of this intended equipment are because the following.Temperature: room temperature to 150��C, which might imitate the temperature condition from the formation with 5000 meters depth.Pressure: confining strain 0MPa to 70MPa, axial strain 0MPa to 200MPa.Imitate the maximum differential pressure of drilling fluid with 10MPa.Sample dimension: ? 25mm �� 50mm.The experimental procedure are as follows.Decide the authentic water articles with the rock samples first, wrap the samples with separation sleeve, and put in to the core holder.
Place the drilling fluid to the tank and check the check program to generate certain it really is in fantastic ailment.Flip within the temperature controller, warm the core samples towards the exact same temperature with downhole situation. Then load the confining pressure and axial pressure to good value and begin timing.During the check, data acquisition control method is used to help keep the test values consistent.Cooling uninstall when the test time reaches the predetermined value (50 hrs within this study), get rid of the rock samples speedily, and measure the water content material at various distance from the finish face.two.one.2.