Oil and Gas Downhole Tubular Failures: Manufacturing and Environmental Case Studies.
Typical downhole failures include manufacturing deficiencies related to heat treatment, ERW tubular defects, seamless tubular defects and/or well environmental issues related to exposure to producing and non-producing environments, such as hydrogen sulfide, carbon dioxide, acid used during hydraulic fracturing and Microbially Induced Corrosion.
The advancements of today’s standards in steel making and processing technologies enables the steel industry to produce cleaner and tougher steels, however even with these advances in downhole tubular technology many manufacturers may encounter systemic manufacturing issues due to the economic competitive environment and the high rate of demand of some of these tubular products.
Less than optimal heat treatment and/or manufacturing defects may result in brittle or weak materials that are more susceptible to fracture. Exposure of these materials to aggressive downhole conditions or high pressures often result in catastrophic failures.
There also exists the possibility of downhole Microbial Influenced Corrosion (MIC) damage. This type of dagame may manifest downhole as accelerated localized corrosion attack and/or a catastrophic Sulfide Stress Cracking (SSC) failure due to H2S generated from sulfide reducing bacteria (SRB). There are several well operational factors that can lead to this type of corrosion damage mechanism that will be discussed.
We will present case studies that showcase failure mechanisms related to manufacturing issues, corrosive downhole producing and non-producing environments, and MIC.