Drill severe dogleg severity (DLS) through formation with a high UCS

INK-Servis faces a significant challenge while drilling a curve in the 8 ⅝-in interval for a well in the Yaraktinskoe field, which is located in the Irkutsk region of Eastern Siberia. The depth in and out is within the 1,300- to 2,500-m [4,265- to 8,202-ft] MD range with a length of about 1,000 m [3,280 ft]. The DLS is 15° to 40°. The section mainly consists of hard carbonates, such as dolomites and anhydrites, along with salt deposits with UCS ranging from 13.78 to 172.37 MPa [2,000 to 25,000 psi]. Drilling would start from the shoe of a previously drilled section (11 5/8-in with 9 5/8-in casing) and proceed down to a dolerite intrusion formation where, in offsets, the BHA was typically pulled out of hole for a planned bit change.

Use bit with unique-geometry cutting elements to improve ROP

Schlumberger used the IDEAS integrated dynamic design and analysis platform and determined that an AxeBlade bit with Axe ridged diamond elements would drill more aggressively and with better impact and wear resistance compared with conventional PDC cutters. The proposed bit would facilitate higher ROP; enable a more stable drilling experience; and minimize shock, vibration, and cutter wear to maximize drilling efficiency.

Shattered field ROP records

Using the AxeBlade bit, INK-Servis achieved a 106% increase in ROP compared with the average penetration rate of offset wells in 2016. ROP improved by 70% in the second run as compared with average results achieved in the first quarter of 2017. Drilled lengths in both runs reached 562 m/d [1,844 ft/d] and 544 m/d [1,785 ft/d], respectively, and set daily drilling records for Yaraktinskoe field. Overall, the AxeBlade bit set six field records (3 ROP and 3 daily length drilled).