Abstract:

Basing on the sensitive analysis of the influence factors in the prediction model of well momentary fluctuation pressure,and the study of well fluctuation pressure and the actual measurement of a full size well, a new prediction model is proposed to predict “the momentary state processing steady state” of the well fluctuation pressure. The model takes into account the influence of fluid compressibility, flow channel elasticity, the empty bottom hole distance under the moving pipes and their longitudinal strain and inertial force.The model can prediet the actual fluetuation pressure value more accurately than the now widely used steady state model，which will be helPful to the scientific hole structure design，the determination of drilling fluid density and the control of the complex problems in a hole.

Key words: Fluetuation Pressure, Pressure predietion, Mathematical model