HORIZONTAL-WELL SIDETRACKING IN ABRASIVE AND HARD FORMATIONS,MOXI GASFIELD

During a geo-steering drilling to horizontal-well reservoir,pay zone often changes very suddenly resulted in a bit offset. So,sidetracking,a high-effective and economic technology,has been introduced and it can choose a more suitable deviation angle to drill freely. As in two wells,Mo 017-H8 and Mo 030-H5,wellbore trajectory is offset reservoir just because formation changes suddenly during geo-steering drilling. So,sidetracking was used to these two wells very successfully and a drilling ratio increases. In this paper,it presents the summary of pay zone in well Mo 017-H8,the sidetracking cause and technological principle,the sidetracking-point selecting basis,the bit assembly,the main technological measures,the drilling summary and effect along with some suggestions.