The distinction of the PDC bit balling and its features of mud logging parameters

To solve the problems of borehole wall instability and bit balling in the deviated section of horizontal gas wells,a biological polysulfonate potassium drilling fluid is developed and applied to 15 horizontal gas wells in Changqing Gasfield.

Based on lessons and experiences learned from the previous countermeasures dealing with drilling accidents, this study put forward a new type of safety joint while drilling which could treat sticking very well, while introducing in detail what the problem of sticking was like and the superiority and strength of this new safety joint.

However, there have been seven sticking accidents happened during the mid stage of development, which has great effect on the exploration and development of the region.

The sticking of the downhole string happened occasionally because great quantity of packers and other tools with slips are used.

Based on groping for and summarization of the processing method drilling failure,and according to the characteristic of drill pipe sticking,this paper proposed a new design for drilling safety joint,which can commendably deal with drill pipe sticking accidents.

In consideration of drill pipe sticking in production of limestone section, it is considered that the sticking is caused by uncleaning wellbore, thus the concept of releasing the sticking by acidizing is proposed.