Risk assessment based on analytical evaluation of structural integrity and life of drilling rig pipe

Corrosion effects on structural integrity and life of oil rig drill pipes

“…One can see that this effect is important, but not significant, since the reduction in the remaining life is 17 %, from about 2.8 years for the new material to about 2.3 years for the used material. One can notice that the effect is much more pronounced for a longer crack, as presented [22], and also shown here in Table 8. One issue remains critical in the approach presented here.…”

“…Using the novel procedure, one obtains 0.28 and 0.37 for the pressure of 10 MPa, new and used material, respectively, as well as 0.62 and 0.82 for the pressure of 22 MPa, also for the new and used material, respectively. Having in mind the medium consequence, as explained in [22], one obtains the risk matrix, Table 6, indicating high risk level for the pressure of 22 MPa and used material. This is the crucial point in the analysis performed here.…”

“…Nevertheless, all of them lack a comprehensive approach, which would include experimental, numerical, and analytical approaches to the problem of corroded pipes and the remaining pipe strength. Toward this aim, several papers were published in the last decade by the authors of the present study, [18][19][20][21][22], including previous experimental investigation on the pipe taken from exploitation in an oil drilling rig after 70,000 hours (8 years) of service [23,24]. In the present paper, the new method, recently introduced and applied for pressure vessels, [25][26][27][28][29], is applied to assess structural integrity of API J55 steel pipes, damaged by corrosion, using risk-based approach.…”