Nano-Enhancement of Elastomers for Improved Downhole Barrier Performance

Abstract

The oil and gas industry is continuously looking for material and tool designs with more robustness that provides greater operational flexibility in aggressive environments. New elastomeric systems that have been enhanced at the nanometer scale have been engineered to address these needs. Nano-enhanced EPDM showed 95-percent lower swelling rate in oil at ambient temperature. Nano-enhanced HNBR compound exhibited 15 times lower absorption in 300°F hydrocarbon fluid. Nano-enhanced FEPM compound showed 20 times lower absorption. Nano-enhanced FEPM bladder material submersed in oil at 300°F yielded a three-fold reduction in the gas transmission rate of a hydrocarbon blend containing both CO2 and of H2S. The same nano-enhanced material showed a 50-percent reduction in the degradation effects of H2S on the NBR physical properties. All of the above are lab results, and the comparisons were made to baseline commercially available rubber compounds without nano-enhancement. Our results demonstrated that nanotechnology can be very effectively used to significantly modify properties of commonly used rubber compounds in the oil and gas industry. The oil swelling rate can be drastically reduced to give operators a greater flexibility in setting the packers and reducing intervention. Sour gas-based slowdown of material retardation translates to higher tool life. These findings can be used to design new packers, sealing elements and other elastomeric components used in downhole environment. This paper will present our recent lab results along with postulated mechanism on how nanotechnologies can impact material performance in downhole applications.

Study of hydrogen sulfide effect on acrylonitrile butadiene rubber/hydrogenated acrylonitrile butadiene rubber for sealing application in oil and gas industry

“…Another example of NBR performance in sour condition was reported in SPE (Society of Petroleum Engineers) as nano-enhancement of elastomer for improved downhole barrier performance. 6 In this study, nano-enhanced NBR (nanoscale coated by polymer system containing branched polyethyleneimine) and polyacrylic acid, with the final crosslinking by glutaraldehyde showed a 50% reduction in the degradation effect of H 2 S in physical properties. It was observed that uncoated NBR could deteriorate in the physical properties like tensile strength in the sour condition of 5% CO 2 /10% H 2 S/85% CH 4 in aging temperature 148.9 C and aging pressure 1.38 MPa under CL-5 oil immersion for 24 h. The tensile strength and the elongation at break of aged NBR reduced by approximately 75% and 25%, respectively.…”

“…Generally, a blister is related to rapid gas decompression (RGD) for oilfield elastomers and typical elastomer compounds used for packer can have RGD damage if the pressure drop or decompression rate is high enough. 6,[14][15][16][17] In our aged test condition, the depressurize rate was very slow (6.9 kPa/min); hence the blister might be related to the formulation of the elastomer such as plasticizer and other additives or interaction with 70% hydrocarbon fluid (70% heptane/20% cyclohexane/10% toluene) in multiphase (gas/seawater/hydrocarbon phase).…”