It used to be that when drillers needed to condition the borehole, the only choice was bentonite. Bentonite did a pretty good job of creating a filter cake on the bore hole wall, however it can restrict the flow of the cuttings while doing so. We find that bentonite is abrasive and can cause excessive wear on down hole tooling and the core bit, shortening its life.
Luckily, technology has allowed certain new products to be developed to address specific drilling issues. Such products include polymers and environmentally safe lubricants which have significantly improved drilling performance. There are 4 drilling fluid additives listed below that when used independently or in conjunction with each other have proven to resolve a very high percentage of issues faced by drillers today. Let’s concentrate on not only getting core in the box, but also extension of your tool life.
DD-2000: Polymers can come in liquid or powder form depending on which is better suited for your operation. Polymers, like DD-2000 (powder form) or DD-1200 (liquid form) coats the inside walls of the borehole, protecting it and helping to control water loss. It also raises the viscosity of the drilling fluids so that cuttings can be more easily flushed out. One added benefit is that it is non-abrasive and helps cool and protect the core bit when mixed with torqueless, resulting in longer bit life. Longer bit life translates into lower operational costs.
Sand Drill: This particular type of polymer is used to solidify non-stable and abrasive grounds such as sand or gravel, both of which are common in geotechnical drilling. In addition to stabilizing the borehole, it helps with core retrieval. With the use of a product such as Sand Drill, the core changes consistency, it can hold together the crumbly core so that is can be retrieved intact.
DD-955: DD-955 is also known as a clay or shale inhibitor. When drilling in clay conditions and your drilling water comes into contact with the clay, the water causes the clay to expand and swell. This swelling can squeeze and put pressure on the drill rods causing your equipment to become stuck in the hole. DD-955 is a product that is absorbed directly into the clay and shale and reduces in-hole swelling and instability.
Torqueless: Reduction of torque leads to longer life of your drilling equipment. Torqueless, an environmentally safe product can be used alone or in combination with other additives, to help bind polymers, lubricate, reduce wear and rusting of the rods and cool the core bit. Using Torqueless enhances all other polymers and should be added to every mix. It ensures proper mixing with the water by encapsulating each grain of the polymer to ensure a thorough mix. It reduces clumping and waste of product, especially if you are using a powdered product.
Beyond these 4 drilling fluid additives, they are many more products developed to address different drilling conditions. To find out more about mixing additives, contact your nearest representative.