Study On Hydraulic Fracturing In-situ Stress Measurement Techniques In Small Holes And Field Application

The principles and methods of hydraulic fracturing in-situ stress measurement technique are discussed deeply in the article. The character of the hydraulic fracturing curvilinear and methods which are used to determine the first fracturing pressure , re-open pressure and close pressure are analysed in the article.The classical equation which is used to calculate the maximum horizontal principal stress is not suitable under high differential horizontal stress field.A new method-comparing model should be adopted to calculate the maximum horizontal principal stress,which is more reasonable.The hydraulic fracturing technique is applied to measure in-situ stress in Jincheng minging area widely.The article discovers the feature of in-situ stress field in mine area of Jingcheng .Specially,the hydraulic fracturing 3-dimeasional in-situ stress measurement technique is applied in Si He Coal Mine,which is the first time to measure 3-dimeasional in-situ stress by hydraulic fracturing technique in Chinese coal mines.The article studys the in-situ stress how to influence enclosing rock deformation and damage by numerical simulation method preliminarily and draws a conclusion that the horizontal stress damages roof and floor mainly and the vertical stress damages wall heavyly.The practice proves that the in-situ stress measurement results can improve the rationality and reliability of roadway support designing.