APPLICATION OF COLUMN MATCHING METHOD IN DESCRIPTIONS OF SPECIAL SHAPE OF DEVIATED WELLS

The parameters equation of parabolic section special curves of deviated wells were set up applying the column matching method and calculation equations of well curvature and bending deflection. Based on the principles of differential geometry, the "Foot plane of dog-leg" raised by Lubinski was demonstrated not being existent. Therefore the three-dimensional analysis of drill pipe assembly and casing stabilizers deduced are not accurate. The author considered that the different calculation methods present are all approximate because of their underestimation of the degree of the practical deviation of the well. The paper recommends taking a strictly controlled value of direction drift of deviated well in standardization of technical specifications and provision with a special trail of borehole to the drilling and production operation contractors.