Pushing the Limits: One Bit, One Section South Iraq Deep Well Case Study

Abstract Cost and operation effective selection of drilling Bits to drill the HPHT Wells sections in Block-09 field in one run with optimum parameters. Improvement in drilling performance leading to reduction in drilling time and costs without compromising the deliverability of well, is the primary objective of drilling engineers. Some of the major challenges faced by drilling engineers are drilling of hard and abrasive formations and selection of durable bits lasting for long while drilling each hole section. Traditionally in this part of south Iraq multiple Tricones and PDC bits were used for each section resulting in long tripping and drilling time. With recent advancement in drilling bits designs and careful and systematic approach for bits selection, these issues have been addressed and tremendous time and cost benefits have been realized. This paper will provide insight into the drilling bits performance for HPHT Wells which have been used in Block-09 field and optimization of bits design to drill and tackle the issues faced in each section with achievement of one bit per section successfully. Dull grading comparison of the bits with offsets wells will be discussed. The optimum bits are then selected by performing a more through response- by-response comparison and how this comparison has been used for next bits selection and outcome of this selection will be presented, in addition the latest technology in bits industry has been benchmarked. The paper will also review the formation types drilled in this block of south Iraq and will help to understand drilled formations and bits design relationship for drilling problematic zones especially sections containing Chert, high strength rocks, anhydrates, Asphaltene and argillaceous Limestone. This paper will discuss the technical challenges which results in major borehole limiters, the engineering design and the Realtime practices that have been developed, as well as the field results. This paper presents the accomplishment, experience and lessons learned related drilling in block-9 field south Iraq area where reduction in drilling time from 141 days to around 63 days is an outstanding outcome of "Pushing the Limits" concept and achieving one bit, one section target.