Experimental investigations of thread compounds viscosity degradation towards long term threaded connections leak resistance

Abstract

Oil and gas leakages represent the (functional) failure mode as a result of sealing failure of thread connections. With the expectation for more safer and efficient operations during the exploration and production phase of oil and gas fields, Oilfield Country Tubular Goods (OCTG) require the use of thread compounds (pipe dope) to lubricate tubular connections during installation, provision of high resistance to presence of galling and ascertain a consistent friction coefficient, thus importantly to improve the sealing performance of API standard connections or among other expectations. In the period of improvement and upturning procedures for thermal enhanced oil, high temperature fluids (around 300 °C) with the production wells having a lower production temperature.To characterize the long-term sealing performance of OCTG threaded connections, this paper presented the experimental comparative studies and, the effect of viscosity degradation of five different types of thread compounds for thread connections samples using a programmable digital rheometer device under influences of shear rate, temperature and different loading conditions. The experimental outcome shows a dramatical transformation of the tested five thread compound's viscosity and how their sealability performance is being compromised. In view of this, the tested samples showed that the reduced viscosity properties will impede the tubulars connection leak tightness and durability in most thermal well's development. Our results also revealed that particular samples do fail at low temperature condition (70 °C) as this may impinge on pipe connections behavior during the breakout operation.