Increasing abrasion resistance of rubber stators
One of the largest Chinese producers of PDM drilling tools, Orient Energy & Technology Ltd., has found that graphene nanotubes improve abrasion resistance of the rubber stator by 20 % and increase tensile modulus by 30 %, resulting in a shortened drilling cycle, reduced energy consumption and less environmental pollution from the drilling equipment. Orient Energy & Technology has completed laboratory testing of nitrile butadiene rubber (NBR) containing Tuball graphene nanotubes supplied by Ocsial. According to Ocsial just 1.7 wt% of graphene nanotube concentrate introduced into NBR was found to increase the tensile modulus by 30 %.
Orient Energy & Technology said that improving the modulus of elasticity is the most valuable advantage of graphene nanotubes in the oil & gas industry, because that leads to a 30 % increase in output torque. With that, the drilling speed can also be increased by more than 20 %, resulting in a shortened drilling cycle, reduced energy consumption and less environmental pollution, greatly improving China’s drilling technology. At the same time, the graphene nanotubes result in a reduction of abrasion by 20 % without increasing the Mooney viscosity of rubber, whereas other additives such as multi wall carbon nanotubes increase viscosity. Orient Energy & Technology is continuing to test Tuball, in particular by studying their effects on other types of rubber, such as HNBR and FKM. Meanwhile, the first industrial prototype of a Tuball-enhanced NBR stator for a screw drill is undergoing industrial trials.
56 % of drilling tool failures in the oil extraction industry are caused by low durability of the rubber stator – one of the most important elements in a screw drill. In China, annual losses from the failure of drilling tools are estimated to be more than USD 40,000 per oil well.