Research on Formation Pore Pressure of Complex Ultra-deep Wells in the Southern Margin of Junggar Basin

The ultra-deep oil and gas reserves in the southern margin of Junggar Basin are large, the proven rate is low, the engineering geological conditions of the lower assembly are complex, and it is difficult to drill and complete ultra-deep wells. The discrimination of abnormal high pressure formation mechanism in the southern margin and the applicability of formation pressure calculation method are studied, which reveals the abnormal high pressure formation mechanism and forms the formation pressure evaluation method of complex pressure system. Considering the parameters of formation acoustic wave, density, porosity and shale content, a comprehensive interpretation model for pore pressure calculation is established. On the basis of formation pressure evaluation, the improvement scheme of wellbore structure in the middle part of the southern margin is studied and formulated. This study explores the interpretation of abnormal formation pressure and the evaluation method of rock mechanics parameters of complex ultra-deep wells in the southern margin of Junggar, which is of guiding significance to the stability analysis of drilling shaft wall in the strong structural area in front of the mountain and provides a theoretical basis for safe, optimal and fast drilling and completion of complex ultra-deep wells in the southern margin.