6 Oil gathering pipeline XXX

6.1 Generating a log of elements and a digital pipeline diagram.

Taking into account the installation locations of instruments and structural diagrams of the pipeline provided by the Customer Appendix 4.1., calculations were carried out for five sections of the XXX oil gathering pipeline:

For each site, a log of elements was generated and a spatial model was built.

When forming the element log, the following assumptions were made:

  • installation locations and types of supports;
  • SOD unit;
  • UZA.

These elements were restored in accordance with Appendices 4.1., as well as a photo report of the execution of natural work.

6.2 Execution of field work to survey the XXX site

6.2.1. An instrumental inspection was carried out on 00.00.0000 using infrasound monitoring devices: Certificate of performance of work on instrumental inspection of process pipelines at the facilities of XXX LLC using diagnostic infrasonic monitoring devices Figure 6.1.

Figure 6.1. Certificate of completion of work

6.2.2. Measurements were carried out at 6 points of the pipeline Figure 6.2:

  • measurement point 1 (device 4) - SOD;
  • measurement point 2 (device 6) - fixed support H-38;
  • measurement point 3 (device 3) - fixed support H-39;
  • measuring point 4 (device 19) - fixed support H-40;
  • measuring point 5 (device 1) - fixed support H-42;
  • measuring point 6 (device 2) - fixed support H-44.

Figure 6.2. Location of measurement points

6.2.3. The amplitude-frequency characteristics of displacements and rotation angles at measurement points are given in Appendix 6.1.

6.3 Calculation of remaining life

Based on the results of calculations of the strength, durability and reliability of the XXX oil gathering pipeline, carried out on the basis of the documentation provided by the Customer and data obtained during the inspection of the pipeline using diagnostic infrasonic monitoring devices (PIK), six elements were identified, the estimated residual life of which is less than 10 years (Tables 6.1- 6.5)

Table 6.1. The most loaded elements of the UZA section are the fixed support N-38

Table 6.2. The most loaded elements of the section are fixed support N-38 - fixed support N-39

Table 6.3. The most loaded elements of the section are fixed support N-39 - fixed support N-40

Table 6.4. The most loaded elements of the section are fixed support N-40 - fixed support N-42

Table 6.5. The most loaded elements of the section are fixed support N-42 - fixed support N-44

The results of pipeline durability calculations for each element are given in Appendices 7.1-11.1

The main reason for limiting the residual life and the reason for reducing the residual life of welded joints and connected parts, respectively, are high dynamic loads (with frequencies from 10 to 100 cycles per day), which lead to the occurrence of cyclic bending moments and non-design longitudinal stresses, increasing due to stress concentrations in the joint area.