The complicated geological conditions will bring great challenges to the drillstring of horizontal wells for the reason that the increase of the well depth in Sichuan-Chongqing region.Since drillstring failure and fri...The complicated geological conditions will bring great challenges to the drillstring of horizontal wells for the reason that the increase of the well depth in Sichuan-Chongqing region.Since drillstring failure and friction during drilling are generally caused by drillstring vibration,great importance must be attached to computer simulation methods for the prediction of drillstring vibration.A finite element model considering axial,lateral and torsional vibration is established.In order to verify the established numerical model,an indoor experimental device based on the similarity principle was established.The vibration characteristics of three shale gas horizontal wells drillstrings are described.The reasons for the large difference in vibration characteristics between the three wells were discussed by changing the well structure,BHA(bottom hole assembly)and drilling parameters.The simulation results show that the depth of ultra-deep well 3 is only 1.27 times of that of medium-deep well 2,but the fluctuation of WOB(weight on bit)is 2.8 times.The primary factor for the great difference of WOB fluctuation is the change of vertical section depth,the secondary factor is the change of the horizontal section length.Additionally,the reasonable range of speeds has been proposed and applied in the field.The advantage of this numerical analysis method is that it can judge the vibration and friction torque of drillstring in horizontal wells with arbitrary structure,drilling parameters and BHA.This method has certain guiding significance to the field practice.展开更多
文摘The complicated geological conditions will bring great challenges to the drillstring of horizontal wells for the reason that the increase of the well depth in Sichuan-Chongqing region.Since drillstring failure and friction during drilling are generally caused by drillstring vibration,great importance must be attached to computer simulation methods for the prediction of drillstring vibration.A finite element model considering axial,lateral and torsional vibration is established.In order to verify the established numerical model,an indoor experimental device based on the similarity principle was established.The vibration characteristics of three shale gas horizontal wells drillstrings are described.The reasons for the large difference in vibration characteristics between the three wells were discussed by changing the well structure,BHA(bottom hole assembly)and drilling parameters.The simulation results show that the depth of ultra-deep well 3 is only 1.27 times of that of medium-deep well 2,but the fluctuation of WOB(weight on bit)is 2.8 times.The primary factor for the great difference of WOB fluctuation is the change of vertical section depth,the secondary factor is the change of the horizontal section length.Additionally,the reasonable range of speeds has been proposed and applied in the field.The advantage of this numerical analysis method is that it can judge the vibration and friction torque of drillstring in horizontal wells with arbitrary structure,drilling parameters and BHA.This method has certain guiding significance to the field practice.
