1.1 Technical condition monitoring (technical diagnostics)
The practice of operating underwater crossings (SC) of main pipelines (MP) has shown that in order to prevent serious accidents and timely implementation of scheduled preventive maintenance, periodic inspection of their technical condition is necessary.
Monitoring of the technical condition (technical diagnostics) of the underwater crossing is carried out by special targeted checks, surveys and measurements using technical diagnostic tools (TD) during operation and repair, as well as after the standard service life.
Monitoring of the technical condition of underwater crossings of main oil product pipelines (MPPP) is carried out by the operating organization with the involvement (if necessary) of specialized organizations in accordance with maintenance and repair schedules.
The use of various non-destructive testing methods, technologies and technical diagnostic tools is one of the effective and promising ways to increase the reliability of main pipelines and especially underwater crossings of the Moscow Oil and Gas Processing Plant. The widespread introduction of diagnostics contributes to the early detection of defects, their timely elimination, and the reduction of labor costs and time required to carry out repair work.
When choosing one or another inspection technology, non-destructive testing method and technical diagnostic tools, it is necessary to conduct a technical and economic analysis and determine the technical and economic efficiency of their use.
Technical and economic analysis and determination of technical and economic efficiency allow:
justify the most rational directions and order of use of certain STDs;
choose the most economical options examination of the MT PP and its operating modes;
define optimal options and rational use of STD;
establish the social effect of the introduction of STD.
The use of certain technical diagnostic tools should be based on taking into account the beneficial results of using STD and the costs of it. A measure of the useful result can be taken as an increase in the reliability of the MN PP, due to the elimination of identified defects. The costs of using STD should take into account not only the cost of the control itself and related operations, but also the losses associated with possible rejection.
The main task of technical diagnostics of PP is to determine the quantitative and qualitative relationships between the factors causing the formation and development of defects and the actual values of the characteristics of defects.
Special targeted inspections of the PP should be carried out by external inspection (walk-through, fly-by, diving and instrument), as well as using in-pipe technical diagnostic tools.
The frequency of inspection of the crossing point is established by the management of the organization operating the crossing.
The controlled parameters when inspecting PP using in-line technical diagnostic tools (in-line inspection tools) are:
actual planned and altitude positions of the PP;
density (presence) of soil around the PP pipe;
diameter (geometry) of the pipe (geometry defects - corrugations, dents, ovality);
pipe wall thickness (pitting and continuous corrosion, cracks, delaminations and other defects).
The result of monitoring the technical condition of the PP should be an assessment of the actual condition and drawing up a schedule of planned preventive maintenance (PPR) to maintain the PP at the design level during operation through timely implementation of maintenance and repair. Work to monitor the technical condition of the main line of the PP using in-line inspection tools (IIS) is carried out in conjunction with an inspection of the linear part of the MNPP section, which includes the PP. Work to monitor the technical condition of the backup line(s) of the PP is carried out separately if the backup line has launch and receiving chambers for cleaning and diagnostic devices.
Controlled parameters, methods and methods of control, frequency of work, results of inspection of the PP are determined in accordance with)