Study On Stability Of Permian Igneous Rock Shaft In Tazhong Ⅰ Gas Field

The problem of Permian igneous wellbore stability in Tazhong-I Gas Field is outstanding-According to statistics, the hole enlargement ratio of Permian igneous rock section averaged20-40%. There are few studies of Permian igneous rock wellbore stability and also not system. Effectively solve the Permian igneous rock wellbore instability problem can significantly reduce the drilling accident, shortening drilling cycle, reducing drilling cost, and provide a efficient key technology in the development of Tazhong-I Gas Field,geology, drilling, logging data of60wells have been collected in the paper, and the analysis of wellbore instability interval correlation and engineering, geology was completed, and then preliminarily determines the Permian wellbore instability factors and types. Launched Permian10groups of complex sections cutting rock mineral component and microstructure analysis, with the aid of15set rolling recovery rate and inflation rate experiment study the water sensitivity characteristics of complex strata. According to the scene with typical drilling fluid formula, preparation of KCl-polysulfide and KCl-polymer drilling fluid system, the evaluation of current drilling fluid rheological property, filter loss, resistance to high temperature and field cuttings hydration inhibition and so on comprehensive performance;By testing the in-situ stress Kaiser, a logging interpretation model of rock mechanics parameters and ground stress, the Permian strata of rock mechanics and formation stress profile. Comprehensive drilling engineering parameter statistics, Permian strata of rock physical and chemical properties, active factors such as performance parameters of the drilling fluid system, gives the Permian mechanism of wellbore instability and collapse prevention countermeasures of drilling fluid.