First Time Application of Bit with Unique-Geometry Cutting Element and Step Change Drilling Automation Software & Torque Reduction System Set New Performance Benchmarks in Northern Kuwait Fields

Abstract

A new cutting element technology bit along with new drilling automation software provides a solution to drill the challenging 12 ¼" section in two fields in Northern Kuwait. The 12 ¼" section was drilled using directional BHA building the angle between 25 to 30 degrees. The formations are characterized to be interbedded limestone and reactive shale causing high downhole vibrations, high torque and stick and slip which affects the buildup capability of the directional tool and overall performance in this section. The main objective is to improve drilling performance by developing an integrated solution to eliminate the downhole tool failures and increase the rate of penetration. The engineering team incorporated a unique geometry into the bit cutting elements design and developed the Ridged Diamond Element (RDE) bit which has new cutting element technology and different geometry than the standard PDC cutters. The ridge shape cutter face helps to reduce the reactive torque generated through the cutter face. The ridge shape cutter face also helps in improving rate of penetration (ROP) by efficient rock removal. With regards to the drilling automation software, the objective is to determine (through the analysis of surface data) the best drilling parameters of RPM/WOB to achieve the maximum ROP for each formation while at the same time detecting and mitigating drilling dysfunctions such as shocks, vibrations and stick slip. The system was operated in advice mode as it will be explained more in detailed throughout the paper. Torque reduction system technology was used to reduce the surface torque variation and reduce the stick and slip by instantaneously altering surface string rotation (RPM). The new cutting element technology in combination with the drilling automation software provide an integrated solution to the challenges faced in the drilling operations for this 12-1/4" hole section. On the first test well, RDE bit and the drilling automation software were used with a motorized rotary steerable system (RSS), to drill 1,060 feet in 15.27 on-bottom hours with an effective ROP of 69.4 feet/hour. The second test well was in a different field, drilling 1,265 feet in 25.22 on-bottom hours achieving ROP of 50.16 feet/hour. Both test runs set new benchmark performance in comparison to the respective field offset wells. This high performance seen in both test runs were enabled by increase in ROP & the significant reduction of downhole vibrations and stick and slip brought by combining the new technologies in bit and drilling automation software. The first-time application of the new technologies helped the operator to solve drilling challenges, increasing performance and reducing the cost per foot by 20%.