RESEARCH AND PRACTICE OF OPTIMUM DRILLING TECHNOLOGY IN BLOCK-12 IN TAHE OILFIELD

The upper formations of the block-12 in Tahe oilfield are unconsolidated and easy to be drilled and tight hole and pipe sticking are prone to happen.While the lower formations tend to slough and cause down hole troubles along with drilling fluid loss due to vertical fracture or caves.On the basis of detailed analysis on formation characteristics and drilling technical challenges in the block-12 in Tahe oilfield,a series of scientific drilling technologies suitable for deep wells in the area are presented,including optimization of casing design,bit selection,compounding drilling of mud motor and high efficiency bits,keeping stable and unobstructed wellbore,deviation control and fast drilling,and high quality drilling fluid,etc.Field application of these techniques show that the rate of penetration was improved greatly.Drilling practices in wells indicate that the drilling speed is increased remarkably;drilling cost is reduced increasingly.The technology plays an active role in enhancing oil exploration,production and development speed,a significant economic efficiency was obtained.