Case Study: Optimized Drilling System Delivers ERIELL Group’s Subhorizontal Well 13 Days Ahead of Plan

Multidiscipline team designs a drilling system that increases ROP and improves performance while maintaining wellbore stability in Russian field

Challenge: Drill 152.4-mm drain section of subhorizontal development well through overpressured formations while acquiring MLWD data for formation evaluation.

Solution: Bring together a multidiscipline team of Schlumberger experts to develop a drilling solution tailored to wellbore challenges, geological requirements, and well profile.


  • Improved on-bottom ROP 30%.
  • Drilled section and run liner to TD, 13 days ahead of plan with no kicks or losses.

Drill through overpressured formations 

Urengoyskoye 4 U0406 is a development subhorizontal well in the Urengoyskoye field operated by ERIELL Group for OJSC Artic Gas. Located in the Yamal Region in north central Russia, the well has a challenging 152.4-mm drain section. Wellbore stability was a major concern because the section was being drilled through the overpressured Achimov formation, making the safe mud weight window very narrow. Adding to the challenge was the need to achieve an inclination of more than 80° at section TD and acquire MLWD data for geosteering and formation evaluation. 

Maintain wellbore stability 

Schlumberger used real-time drilling geomechanics during planning and execution. Drilling practices and wellbore quality were optimized, and risks associated with wellbore stability were minimized by enhancing MEGADRIL oil-base drilling fluid with low, flat rheology and reduced gel strength, which provided proper hole cleaning and reduced circulating pressures. 

The BHA paired a fit-for-purpose PDC bit from Smith Bits, a Schlumberger company, with a PowerDrive X6 rotary steerable system. Drilling parameters were optimized using the IDEAS platform. A ShortPulse integrated MWD and gamma ray tool for real-time mud-pulse telemetry, PeriScope bed boundary mapping service, adnVISION azimuthal density neutron service, and SonicScope multipole sonic-while-drilling service were used to acquire accurate, real-time sonic, resistivity, density, neutron-porosity, and annular pressure data that was combined with surface drilling data for real-time drilling geomechanics analysis. The analysis allowed the drilling team to assess hazards and act quickly to optimize ROP, maintain wellbore stability and quality, and avoid the need for wiper trips.

Reach TD in less time than planned 

The fit-for-purpose drilling system delivered the fastest and longest well successfully drilled through the Achimov formation. Using the real-time drilling geomechanics workflow and integrating drilling technologies minimized the risk of wellbore instability. On-bottom ROP was 30% greater than ROP in offset wells. The drain section was drilled and liner was run to TD 13 days ahead of plan.

Download: Optimized Drilling System Delivers ERIELL Group’s Subhorizontal Well 13 Days Ahead of Plan (0.06 MB PDF)

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Section Drained and Liner Run to TD 13 Days Ahead of Plan

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