Analysis, Comparison, and Results of the Effectiveness of a PDC Bit Containing Fracturing and Shearing Elements When Drilling Challenging Heterogeneous Section Containing Massive Cherts

Abstract

A new PDC Bit design containing fracturing and shearing elements which can deliver improved ROP in a single trip to drill a challenging heterogeneous section containing massive chert compared to previously used conventional hybrid or roller cone bit designs. The demonstration is supported by a real field case from an unconventional gas exploratory field project in Abu Dhabi. In this unconventional field, 6 wells have been drilled using 4 Bits on average to complete the 12 ¼″ section (Tricone and PDC) where the presence of chert has resulted in additional trips due to Bit life. The massive content of abrasive cherts is approximately 2,000 ft thick, reason why it was decided to think of a new customized PDC Bit design and use it in well # 7. Plan is to prove that is possible to introduce an alternative option to complete the section in one trip and stablish a comparison with previous wells where Hybrid Bits were used. The new unique PDC design features dual row cutters, new shaped cutters, advance elements to reduce vibration and sensing at the bit technology to increase the efficiency in rock interaction. It will be used in the ongoing exploratory project to demonstrate its advantage in terms of cost saving and rig time reduction. Reduction target at least 15% is anticipated while increasing the ROP and eliminating a trip across the chert formation. The study will compare the data with previously used Hybrid Bit and create a basement for the exploratory field in 12 ¼″ section. A strong hypothesis is that this bit will complete the well in this particular area and optimizing drilling cost in development studies. All the analysis, studies and design have been done and completed during Q2 and Q3 Where such non-homogenous formations containing massive abrasive cherts can be crossed and have detrimental impact on the bit life, the novelty is to bring to the stage a new PDC bit, which will be able to offer a different alternative by reducing torque, having healthier wells, and optimizing drilling cost in this unconventional field where drilling CAPEX reduction are paramount.