Advanced compounds extend downhole drilling time. Hydrogenated acrylonitrile butadiene (HNBR) compounds have been developed specifically for downhole Mud Motor Boots. These compounds offer improved mechanical properties, toughness, and fluid resistance leading to extended drill time. See the physical properties listed in the chart below for the HNBR compounds KA261-60, KA246-70, KA271-70, and KA281-80 that Parker has to offer.
Mud Motor Boots must perform in harsh environments of drilling fluids and high temperatures without failure, in order to protect the drill string. Boots must operate in a vast array of water and oil based muds specifically formulated to enhance drilling productivity, often at the expense of rubber articles. Specific compounding is required to overcome these obstacles. Downhole temperatures during mud circulation can exceed 300˚F, placing additional stress on the boot. Debris contained in the mud is circulated at high flow rates which can abrade the boot surface, leading to premature failure of the rubber. Operation of the drill string places the boots under severe mechanical loads causing flex and torsional fatigue. Customer feedback has shown that competitive mud motor boots experience field issues, which has driven Parker to the development of new compounds for the market.
Parker benchmarked industry standard boots using downhole muds and high temperature mechanical properties to validate its newly developed HNBR compounds. The compounds have been evaluated at 350˚F and show performance enhancements over competitive boot compounds. While testing in drilling mud procured from the drilling site, it was determined that the current rubber boots were undergoing chemical degradation leading to premature failure. Parker’s expertise in material compounding overcame the fluid resistance barrier to produce a material that extends the drilling time available. Field testing of the new boots reduced the failure rate to zero.
This article was contributed by Ericka Norris, Oil & Gas Market Manager, Parker Engineered Seals Division.