Performance Report: Bakken Shale: OPTM-IZER Closed Loop Approach Delivers in Zero Discharge Operation

Challenge: Owing to rising disposal costs and tightening environmental restrictions, a Bakken Shale operator requested a proactive solution that would move it closer to a total closed-loop drilling operation. The operator’s past experience with closed-loop systems was costly and inefficient with no transparent value. What’s more, previous conventional attempts were ineffective in handling the considerable volume and size of the cuttings generated during high ROP surface drilling intrinsic of North Dakota’s Bakken Shale. Furthermore, the intermediate and production oil-base mud (OBM) and brine sections, respectively, also raised concerns of high ROP combined with the need to either reduce or increase mud density very quickly to manage the ECD and avoid losses or influxes.

Consequently, any closed-loop package design would be required to maintain density and other fluid properties in the water-base mud surface sections, the oil-base mud intermediate sections and the brine-base production interval without having to dilute and dispose of fluids.

Solution: M-I SWACO immediately began to design a client-specific package that would meet the following requirements:

  • Mobility and timely installation
  • Winterization / harsh environment functionality
  • High-capacity dewatering and centrifugation
  • Spill prevention via an automation/control package
  • Barite recovery (preferentially removing low-gravity solids (LGS) in weighted systems)
  • Reduced liquid-on-cuttings (LOC) being discharged into the cuttings pit. This would cut closure costs if no free liquid is present.

Upon completion, the M-I SWACO customized OPTM-IZER closed-loop package was mobilized to two of the client’s drilling locations.


  • All fluid from surface and tank cleaning slop was processed and stored in upright storage tanks for use on the next well.
  • Tank cleaning and tank bottom processing were completed while running casing and the cement job was completed without impacting the drilling schedule.
  • No issues were encountered during the casing run; no mud rings or drilling issues were reported while dewatering operations were used.

The initial installation was quick and easy, required only one truck and no crane picks, and initial operations commenced with only minor adjustments. The specially designed system effectively handled the cuttings volume regardless of the flow rates to the centrifuge packages. No dilution was required on the surface and all fluid was recovered and recycled for future surface holes. In keeping with the M-I SWACO commitment to continuous improvement, the performance on each surface hole improved over the preceding well.

Well # Bit Size (in/mm) Surface TD (ft/m) Mud Wt. (PPG / SG) Circulation Rate (GPM / LPM)
Confidential 13.5 / 343 1835 / 559 8.7 / 1.04 750 / 2839
Confidential 13.5 / 343 1835 / 559 8.6 / 1.03 750 / 2839
Confidential 13.5 / 343 1835 / 559 8.5 / 1.02 750 / 2839

During the operation, the M-I SWACO design team quickly modified the centrifuge discharge chutes to allow for higher than anticipated solids volume. Consequently, all initial OPTM-IZER designs in the future will incorporate the larger discharge chutes. The Bakken Shale experience validated the OPTM-IZER closed-loop package, in conjunction with additional recovery equipment if required, as efficient and cost-effective solution for zero-discharge drilling.

Download: Bakken Shale: OPTM-IZER Closed Loop Approach Delivers in Zero Discharge Operation (0.51 MB PDF)

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“The mobile OPTM-IZER package effectively demonstrated to our client the effectiveness of a well-designed and operated closed-loop drilling system.”
Mike Kirby
Senior Technical Service Engineer