Optimization of Drilling Technology Used in the Deep Layers in Anpeng Oilfield

In view of the characteristics of formations in An-peng block and in combination with the problems oc-curred in2000,the following drilling technical measures were applied:selecting suitable drill bit type by using in-terval transit time logs;changing the location of wellhead ac cording to formation drifting pattern;using dual -dampers and a mode of heavy bit weight matched with high speed of rotation;and utilizing different drilling fluid systems in different intervals.Field application in12ⅢMay2002Henan Petroleum wells showed that penetration rate increased by a factor of47.28%and well construction period shortened by a factor of44.61%.