| Based on the extensive reviews of current developments, the technical status and the development directions in the wellbore stability, combining the real situation of Shengli Oilfield, this paper has analyzed different influential factors of wellbore stability. The methods concerning the determination of in-situ stress and the shale strength under original wellbore condition are studied with the emphasis on the combining effects of rock mechanics and physical chemistry on the wellbore stability. Mechanical calculations are performed based on the relationship between the strength and the water content of shale core from the Sha-san Section of Shengli Oilfield. The linear-elasticity plane strain mechanical model is established, the quantitative relations of different factors on the influence of wellbore stability are analyzed and the reasonable density of both oil-based mud and prohibitive water-based mud are presented which provide scientific references for the site operations. The descriptive procedure is established by combining the hydraulic fracture data, the density logging data, the formation pressure data and the dip angle data with the crustal stress, and the interpretive method of horizontal crustal stress is clarified from the viewpoint of wellbore stability theory.
|
PDF Full Text Request