Innovative Solution for Drilling Pre-Khuff Formations in Saudi Arabia Utilizing Turbodrill and Impregnated Bits

摘要

The abrasive Pre-Khuff sandstones combined with high downhole temperatures and the propensity for BHA and bit sticking present a uniquely hostile drilling environment. These limit run durations and the ability to optimize ROP with the use of conventional rotary assemblies, PDMs/conventional turbodrills and/or rotary steerable systems. Catastrophic damage or loss of drill strings, poor hole quality and logging problems are common even with the advancements in PDC bit technologies. Of the systems listed above, historically, turbodrilling systems have best addressed the high temperatures and the abrasive nature of the Pre-Khuff formations and held the potential for drilling economics optimization but have been unsuccessful in addressing bit sticking challenges. The resultant development of best practices produced only marginal results because they require surface intervention and thus did not fully address sticking problems (in particular bit sticking). The engineering challenge was to develop a downhole device that automatically engages and imparts sufficient drill string torque to maintain bit rotation. The turbodrill device disengages when conditions return to normal and returns the operation to high productivity drilling without surface intervention. The turbodrill device coupled with advancements in BHA design, stabilizer and jar placement along with formation characterization and drill bit technology, is the solution to bit sticking incidents. Presented with this advancement in turbodrilling technology, the Operator/Service Company team has completed trials using this technology and presents data that supports the use and benefits of anti-sticking techno1ogies. With this success, the team has regained focus on drilling optimization and reset the goal for single run-casing point to casing point.