New model for forecasting drag and torque in Extended Reach Well.;

Analysis on friction drag and torque from extended reach wells and the influence on well drilling depth;

Optimization design methods of drilling strings in extended reach wells;

In view of existing situation of the extended-reach wells (ERW), a new mechanics model for the torque and drag calculation of the whole drill-sting is established with gap element method in extended reach wells and it considers for drilling fluid, contact friction and local bending of drilling-string.

To reduce the application of oil based drilling fluids in extended reach wells,water based drilling fluids was developed for Liuhua Oilfield.

Static pressure of fracturing fluid and wellbore frictional resistance in the procedure of fracturing the extended reach wells (ERW) is related to the wellbore trajectory, well deviation angle and operation condition etc.

This approach was used to calculate and analysis the case of Liuhua 11-1-17 B3 ERW4 well.

Based on regular method and characteristics of ERW, the distinction of hydraulics design of ERW was analyzed.

A Three layer model for cuttings transport in ERW is proposed based on the law of mass conservation and momentum theorem.

Calculating model of torque and drag in extended-reach well;

Based on the comprehensive analysis of logging data,geological information and laboratory tests results,this paper studied the pore pressure,in-situ stresses and rock strength of Liuhua 11-1 oil field,analyzed the borehole stability during the drilling of shale and limestone payzones for extended-reach wells,and calculated the safe mud density window for the extended-reach wells.

Casing wear is one of the inevitable problems during the drilling process, especially more serious in deep wells, ultra-deep wells, high-angle wells, and extended-reach wells, etc.