Even drill bits cost are about 3-5% of the total drilling budget, but bits performance affects as much as 60% of the drilling cost[1] that would explain the necessity of continuous studying and developing this tool to improve drilling performance. Unfortunately, most of Iraqi oil fields managed by states companies does not give the proper attention for bits optimization issues, that would cause insufficient bits used to drill a certain formation due to the absence of a serious dealing with formation hardness and other bit selection criteria while designing, or making bits purchases contracts, or they would satisfy by a minimum rates of penetration.
Unfortunately, the bit selection issue is matched the optimum selection for the drilling parameters issue, it is a matter of tri and error [2].
In this study, a southern Iraqi oil field located in Basra region have been selected to optimize the bits used to drill its wells.
Summarizations of bits selection methods have been reviewed, advantages and disadvantages of possibility to applicant those methods in Basra regions have been introduced. A proper algorithm for selecting bits in Iraq was also presented. An economic evaluation for a different bit type's strategies used to drill holes of Mishrif wells in Basra oil fields region also discussed.
This study improve that using bits holding the IADC code 425, M322 PDC bit with 6th blades and 16mm cutter size and M323 PDC bit with 5th blades and 6mm cutter size are the optimum selection to drill the surface, intermediate, and production holes consequently.
This study is applicable to all Iraqi oil fields and especially for Basra region oil fields due to its large analogous on the lithology column and the drilling problems may combined the drilling operations among the different oil fields in this area.
An Optimum Bits Selection for a Southern Iraqi Oil Field Located in Basra Region by Depending a New Algorithm