The Situation

Non-aqueous drilling fluids are used routinely for extended reach drilling in North Dakota’s Bakken Shale. With winter temperatures dropping as low as <-31° C (-23.8° F) mixing of liquid chemical additives that normally are packaged in drums becomes a significant challenge. Liquid emulsifiers are particularly affected by cold temperatures, often becoming extremely viscous due to pour point limitations.

The Solution

M-I SWACO engineered Actimul RD dry emulsifier as a dry additive, specifically to alleviate the problems associated with mixing liquid emulsifiers in cold weather and remote locations with restricted logistics. Actimul RD dry emulsifier reduces costly logistic issues associated with transport of heavy drum materials. Depending on fluid cost and density, the recommended concentration of Actimul RD is around 50-66% by weight versus comparative liquid emulsifiers. Thus, less transport weight is required to achieve the same treatment requirements.

The Results

The Actimul RD dry emulsifier was applied in Bakken Shale producing well and performed as designed under cold winter conditions. Mixing was carried out easily both in the mud plant and at the rig. Actimul RD was incorporated in a Megadril* oil-based mud and exhibited fluid properties comparable to those exhibited with the Megamul* liquid emulsifier. Drilling of the extended reach well was carried out on schedule and within budget. No fluid-related problems were reported.

The Details

A field trial to evaluate the Actimul RD as a replacement for the Megamul normally used was conducted near Stanley, ND from Dec. 16 2010 to Jan. 17th, 2011. Approximately 1,500 bbl of 1.1 s.g. (9.7 lb/gal) Megadril diesel-based fluid was mixed at the nearby M-I SWACO plant. Actimul RD retained all the rheological properties as per specification at a lower emulsifier concentration. No torque or drag was reported while drilling the two sections. The 114.3 mm (4 ½ in.) production liner was run to bottom at 5,715 m (18,750 ft) MD, 2,715 m (8,907 ft) TVD with no problems or issues. Three more wells subsequently have been drilled with this fluid system with good results. On these wells, a working concentration of 8.56 - 11.41 kg/m3 (3 - 4 lb/bbl) has proved adequate for delivering the required rheological/chemical parameters.

Summary

• Thermally stable to >205°C (>400 °F)
• Easily mixed at any temperature
• Alleviates mixing and storage challenges with liquid emulsifiers
• Reduces waste steam and costs associated with drum disposal
• Can be used at lower concentration than liquid emulsifiers
• Eliminates HSE challenges of handling drums over the mud pits
• Solubilises quickly in many different non-aqueous fluids

Questions? We’ll be glad to answer them. If you’d like to know more about Actimul RD and how it is performing for our other customers, please call the M-I SWACO office nearest you.