Schlumberger

Case Study: Sahara WCS Sees ROP Increase 55%, Saving 6.5 Days Drilling in Algeria’s Berkine Field

PDC designed with IDEAS platform sets ROP record drilling 16-in section through interbedded formations, reaching TD in one run

Challenge: Reduce drilling time on Block 405a well sections in Algeria’s Berkine field.

Solution: Design an application-specific drill bit using IDEAS integrated drillbit design platform and enhance drilling parameter selection with ROPO rate of penetration (ROP) optimization software and DBOS OnTime real-time drillbit optimization service.

Result: Drilled a 2,030-m, 16-in section in one run, setting a record and saving 6.5 days of rig time.

Minimum drilling time required for 16-in section

For Sahara WCS, a joint-venture between Schlumberger IPM and ENAFOR, completing 16-in vertical sections in Algeria’s Berkine field involved drilling 2,000 to 2,200 m through interbedded formations that have an unconfined compressive strength (UCS) of from 1,000 to 25,000 psi. Drilling these sections to TD required multiple runs to replace worn bits and those with chipped teeth, and which were logging a disappointing 22.75 m/h average ROP. Faced with drilling another 16-in vertical section for their WEMN-12 well in the Berkine field, Sahara WCS wanted a bit that could drill the section in one run with improved ROP.

Customized PDC bit used with ROP optimization software

Starting with a standard 16-in PDC design, Smith Bits engineers used IDEAS design platform to identify a bit design that could be optimized for every element of the BHA. With a number of modeling tools, offset data, and an extensive database at its disposal, the team accurately defined and simulated the dynamic interaction between the rock and bit cutters. Analyzing drilling assembly dynamics through multiple formations with varying compressive strengths was essential for maximizing performance through formation transitions.

Based on their findings, bit design engineers selected a 16-in MSi916LVPX PDC bit equipped with ONYX PDC cutters for Sahara WCS’s application. ONYX cutters are proven to remain sharper longer than most other cutters, which increases ROP and footage drilled. Thermally stable polycrystalline diamonds provided extra protection to the gauge, while managed depth of cut minimized cutter breakage and torque in the heterogeneous formations. ROPO ROP optimization software and and DBOS OnTime real-time drillbit optimization service monitored drilling parameters and performance in real time.

It automatically identified formation changes and recommended the weight on bit and surface rotary speed required to instantaneously maximize ROP within the specified safe operating envelope.

Over six days saved with record ROP and single trip

Compared with other bits drilling offset wells at an average ROP of 22.75 m/h, the 16-in MSi916LVPX PDC with ONYX cutters averaged an ROP of 35.44 m/h.

This set a field record and represents a 55% improvement in ROP. The bit was pulled in good condition after drilling the 2,030-m 16-in section in one run and 6.5 days ahead of plan. This same bit design has since been used to drill five additional wells in Block 405a, performing more consistently than other bits and completing sections in one run with good hole quality, with an average ROP of 32.26 m/h.


Download: Sahara WCS Sees ROP Increase 55%, Saving 6.5 Days Drilling in Algeria’s Berkine Field (0.58 MB PDF)

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Bit performance comparison in the Berkine field
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