In order to tackle this problem and effectively control hole deviation and increase penetration rate, an offset-axes bottom-hole assembly is experimentally applied in Qingxi area.

Correlation study on drilling weight on bit (WOB) fluctuation rules of pendulum assembly and unbalanced assembly was carried out by using simulation device for bottom hole assembly (BHA).

Dynamic model of bottom hole assembly used in pre-bending dynamic vertical and fast drilling technology;

Sensibility analysis of the factors affecting the stress level of bottom hole assembly;

Dynamic analysis of the hinged bottom hole assembly;

The paper presented the profile optimizing technique,make-up of string,trajectory control technique,and MWD GAMMA geologic survey technique.

The bottomhole assembly,drilling parameter and hole trajectory control method in the application are discussed.

Through analyzing and calculating the force subjected to by the flexible antisticking bottomhole assembly,which is accompanied by φ127mm weighted drilling pipe,this paper obtained the bit weight and the qualitative relationship between the distance from the center of φ195mm square connection to the bottom of bit and the change rate of azimuth and hole deviation.

In addition,some technologies of improving drilling speed are also presented,including special PDC bit,anti-collapse and anti-leakage drilling-fluid system,optimized bottomhole assembly and drilling parameters.