Study On The Cracking Mechanism Of Shallow Sandstone Hydraulic Fracture

According to the reasons of lost circulation in shallow sandstone it can be divided intothree categories: artificial hydraulic fracture leakage, natural channel leakage and inducedcrack leakage. To the shallow sandstone well lost circulation problems, by applying elasticmechanics theory，studies the surrounding shallow sandstone shatf in complex stress state, theworking fluid, effect factors, and analysis of the well bore and fracture is related to the stressifeld and the formation fracture pressure. The shallow sandstone, the main factors of jointrock mechanics parameters, in-situ stress, wellbore deviation around the complex stress ifeld,The shallow sandstone well leakage prevention is the key to accurately obtain theformation fracture pressure. Through the mode】，analysis of the deviation respectively alongthe maximum pirncipal stress direction and the minimum principal stress direction tilted,joint effect of pressure angle and azimuth of hydraulic fracture. Mechanism of seam byshallow sand hydraulic fractuirng, the leak proof plugging shallow sandstone measures.