Abstract: Hitherto our drilling industry is disturbed with challenges of optimal bit selection due to the fact that current bit models in market are bias to very hard Formation like Hard Streak. At Soku Oil field of Niger Delta, Nigeria, West Coast of Africa, there exits challenges in the proper bit to drill the section of the hard Formation, which is associated with siliceous-ferrogenous sandstone with traces of siltstone rapped in augen of shale. This segment of formation affects every inch of drilling – from the bit in the drilling string to drilling tools, mud, hole diameter and general rig operation. Engineers that specialize in bit optimization, including Directional Drillers, possess the analytical skill to evaluate drilling problems in a methodical fashion, carefully considering the larger context of the drilling process. Therefore, to tackle the menace of the hard streak, great experience, regrouping and remodelling of the existing models were done. Data for this study were gathered through personal observation as a Directional Driller at Soku field. Others were from Shell, Nigerian National Petroleum Corporation (NNPC), Directorate of Petroleum Resources (DPR) and further research from internet. The data were subjected to analytical methods, presented in tables, figures and charts. Based on the data analysis, the findings of the study are that:
* Insert bits are perfectly good to drill all sections of hard streak provided rotation at bottom is not more than 36 hours, less cones are lost.
* The use of PDC bits to drill or ream through the hard streak is an aberration while insert bit (447) is the best for drilling hard streak.
* Regrouping of International Association of Drilling Companies (IADC) Code and remodelling of current models in the market were inevitable to accommodate selection of bits for the hard streak.
* The use of steerable motor all through a hard streak to reduce axial lateral vibration on Drilling String is recommended.
Keywords: Hitherto our drilling industry, PDC bits, Directorate of Petroleum Resources (DPR).
Title: Remodelling Bit Selection Model
Author: VICTOR U.K. OGUJIOFOR, ADEWALE DOSUNMU (PROF.)
International Journal of Engineering Research and Reviews
ISSN 2348-697X (Online)
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