The Study Of Borehole Sloughing Period In Shale Formation Of Shahejie Of North Dagang Oilfield

Wellbore instability of shale is a complicate and worldwide problem, and many research works have been done from 1930's to 1990's, several math models coupled with multi-fields have been developed. The development of mechanics from elasticity Research to Mechanics-Chemical Experimental Research. But, because the complexity of multi-fields-coupled problem, many parameters in these models can't be measured in lab, that decreased the reliability and applicability of models seriously. On the other hand, when used the parameter to analysis the borehole sloughing period, the other elements which affected the parameter was not considered ,so the Effects wasn't well. Used the new measuring methods of two main parameters in lab,And Part parameters was amended in this paper,so the practicability of this model is increased.Modified the apparatus of the Mechanics-Chemical Experimental and the methods in testing, enhighted the efficiency and the accuracy of testing. Base on the theory of The Borehole Wall Sloughing Period ,And used the methods of testing in house to detect the parameters of Shahejie of north Dagang oilfield.Which is the base of The Borehole Wall Sloughing pressure .The regularity of The Borehole Wall Sloughing Period of Shahejie of north Dagang oilfield was analyzed used the software of Mechanics-Chemical Experimental. Some conclusion can be got that lower water activity and lower temperature of mud and higher membrane efficiency are benefit to borehole stability.