| With the development of oil and gas reservoir resources at home and abroad,conventional oil and gas reservoirs have been gradually run out.In order to exploit the various complex oil and gas reservoirs,the long horizontal section well technology has gradually become an important core approach.The torque and drag problem is a core issue in the drilling of long horizontal section wells.Therefore,this paper is of great significance to study the toque and drag prediction model of long horizontal section wells and the friction reducing technology for it.Up until the present moment,the published torque and drag calculation models rarely consider the influence of the drilling circulation temperature.To study the effect of that,drilling fluid samples is taken from Fuling shell gas field,Jiaoshiba zone,Chongqin province to conduct the indoor experiments to study the law of temperature effect on lubricity factor and mud cake frictional factor.Based on the experiment results,the friction coefficient in a previous torque and drag model is modified.Moreover,considering the extra axial force caused by thermal stress,a new torque and drag calculation model is built.A field case of Jiaoshiba X well is analyzed based on the new model above,the errors of top drive torque and hook load are 3.7% and 4.4%.The top drive oscillation friction reducing technology,which rotates the drilling pipes clockwise and anticlockwise,can effectively solve the fricion problem in sliding drilling condition of horizontal wells.The domestic theorical research on this kind of technology is still in its infancy.The previous 2 dimension mechanical model of this technology is optimized in this paper by considering azimuth and temperature effect.Consequently,a new 3 dimension model is built and a calculation software based on it is developed.This research is in great significance for applying the technology in fields. |
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