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This standard is developed in accordance with the rules given in G/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
This standard replaces SY/T 6597-2014 Specification of in-line inspection for oil and gas pipeline, SY/T 6825-2011 ln-line inspection systems qualification and SY/T 6889-2012 In-line inspection of pipelines. This standard is based on the content of SY/T 6597-2014, and integrates related content of SY/T 6825-2011 and SY/T 6889-2012. In addition to editorial changes, the following main technical changes have been made with respect to SY/T 6597-2014:
——Some terms and definitions are modified and supplemented, which are consistent with the current standards (see Clause 3);
——The “General requirements” is modified and supplemented (see Clause 4);
——The requirements for inspection flow are added (see Clause 5);
——The performance specification requirements of in-line inspection tool are modified and supplemented (see 6.2);
——The requirements for inspection implementation operation plan, marking and tracking, and inspection operation report are added (see Clause 8);
——The requirements for bending strain report and submission time of inspection results are added (see 9.5 and 9.6);
——The requirements for verification of inspection results are modified and supplemented (see Clause 10);
——The requirements for verification of performance specification of inspection tool are added (see Clause 11);
——The requirements for inspection data management are added (see Clause 13);
——The requirements for adaptability of newly-built pipelines are added (see Clause 14);
——The requirements for inspection risk control and emergency disposal are added (see Clause 15);
——The requirements for inspection service provider are added (see Clause 16);
——The types and applicability of the inspection tools are modified (see Annex A);
——The list of performance specifications of inspection tools is added (see Annex B);
——The examples for performance specifications of inspection tools are modified (see Annex C);
——The verification methods and processes of defects are added (see Annex H);
——The examples for verification of performance specifications of inspection tools are added (see Annex I).
This standard was proposed by and is under the jurisdiction of the Technical Committee for Standardization of Oil and Gas Storage and Transportation.
This standard replaces SY/T 6597-2014, SY/T 6825-2011 and SY/T 6889-2012.
The previous edition of SY/T 6597-2014 is as follows:
——SY/T 6597-2004.
Specification for in-line inspection of oil & gas pipeline
1 Scope
This standard specifies the technical requirements for in-line inspections such as geometry inspection, metal loss inspection, crack inspection and centerline mapping of oil & gas pipelines.
This standard is applicable to in-line inspection of onshore steel oil & gas pipelines, and may be referenced for in-line inspection of submarine steel oil & gas pipelines.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 32167 Oil and gas pipeline integrity management specification
SY/T 0087.5 Standard of steel pipeline and tank corrosion assessment - Part 5: Comprehensive analysis of corrosion data for oil and gas pipeline
SY/T 5536 Specification for operation of crude oil pipelines
SY/T 5922 The operation regulation of gas pipeline
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
in-line inspection (ILI)
method of inspecting the defects (corrosion, damage, deformation, crack, etc. of the inner and outer walls), centerline position and structural features (welds, tees, bends, etc.) of pipelines with the help of fluid pressure difference
3.2
geometry inspection
in-line inspection of pipelines with the main purpose of inspecting the geometric deformation of pipe body
3.3
metal loss inspection
in-line inspection of pipelines with the main purpose of inspecting the pipe wall corrosion, gouge and other metal losses
3.4
crack inspection
in-line inspection with the main purpose of inspecting cracks in pipe wall
3.5
magnetic flux leakage (MFL)
in-line inspection technology that magnetizes the pipe wall with magnets and inspects the defects and pipe features in pipe bodies and welds depending on the change of magnetic flux
3.6
inertial mapping
in-line inspection by mapping the spatial position of pipeline centerline using inertial sensor, which can generate pipeline elevation and plan through analysis
3.7
in-line inspection tool
equipment or tool for inspecting the defects (corrosion, damage, deformation, crack, etc. of the inner and outer walls), centerline position and structural features (welds, tees, bends, etc.) of pipelines with the help of fluid pressure difference
3.8
gauge plate
soft metal disc (usually aluminum disc) with a diameter less than the nominal inner diameter of the pipeline, which is installed on the pig to qualitatively determine the deformation degree of pipeline
3.9
above-ground marker (AGM)
portable or permanent equipment placed above the pipeline, which can detect and record the passing signal of the in-line inspection tool, or of which the signal emitted can be detected and recorded by the in-line inspection tool
3.10
marking
work of setting ground measurement reference points in order to locate the detected pipeline features accurately and track the operation state of inspection tool in the inspection process
3.11
performance specification
a series of technical indexes used to determine the inspection, classification and characterization capabilities of in-line inspection tool
3.12
detection threshold
critical value that a certain feature size shall exceed in order to obtain the specified probability of detection
3.13
reporting threshold
parameter indicating whether an anomaly shall be reported, which may be a limit value about the depth, width or length of an anomaly or feature
3.14
probability of detection (POD)
probability that a feature can be detected
3.15
probability of identification (POI)
probability of correctly identifying detected anomalies or other features
3.16
sizing accuracy
accuracy of reported anomaly size or characteristics, which is usually expressed in terms of tolerance and certainty. For example, the sizing accuracy of the depth of metal loss may be expressed as a wall thickness with a certainty of 90% and a tolerance of ±10%
3.17
certainty
probability that the anomaly feature reported by the test result is within a given tolerance range
3.18
confidence level
probability that the overall parameter value falls within a certain interval of the sample statistical value, which is used to describe the certainty of data under specified conditions
3.19
tolerance
range used to estimate or characterize the anomaly size or characteristic under a specified certainty
3.20
interaction rules
rules of interval between anomalies established when the adjacent anomalies are treated as a single larger anomaly
3.21
feature
all physical objects detected by the in-line inspection tool, which may be anomalies, components, adjacent metal objects, welds, appendices, etc.
3.22
characteristic
physical description of pipeline (such as grade, wall thickness and manufacturing method) or anomaly (such as type, size and shape)
3.23
anomaly
unverified deviations from normal in pipes, coatings or welds
3.24
defect
anomaly with size or characteristic exceeding acceptable limit
3.25
imperfection
anomaly with size or characteristic not exceeding acceptable limit
3.26
deformation
permanent change in shape, such as bending, buckle, dent, ovality, ripple, wrinkle or other changes that affect the roundness or straightness of pipeline section
3.27
dent
local elastoplastic deformation in which the curvature of the pipeline surface changes significantly due to impact or extrusion by external force
3.28
ovality
degree of deviation of the pipeline cross-section from the normal graph, which is calculated using the formula: ovality (%) = (maximum diameter - minimum diameter) / nominal diameter
3.29
wrinkle
smooth and locally convex part of the outer wall of a pipe
3.30
buckle
large plastic deformation of the pipeline, resulting in permanent wrinkling or deformation of the whole pipeline or pipeline section
3.31
metal loss
any anomaly in pipeline with metal loss, which is usually caused by corrosion, but may also be caused by scratches, manufacturing defects or mechanical flaws
3.32
corrosion
deterioration of a material (usually metal) due to chemical or electrochemical reaction with its environment
3.33
pitting
metal loss confined to a local area on a metal surface
3.34
gouge
elongated groove or cavity caused by mechanical cutting of metal
3.35
crack
fractured discontinuity, which is mainly characterized by sharp tips and large length-width ratio at the opening displacements
3.36
stress corrosion cracking (SCC)
a kind of crack in material resulting from a combination of tensile stress (residual or applied) and a corrosive environment
3.37
lamination
delamination due to internal separation of metals, which is usually parallel to the surface
3.38
cold work
permanent strain that accompanies the deformation and hardening of metals
3.39
hard spot
local spot with higher hardness through the pipe wall due to local quenching in the hot rolling process of steel plate
3.40
component
physical parts of pipeline except pipe body, including but not limited to valves, welds, tees, flanges, fittings, small openings, branch joints, outlets, supports and anchorage, etc.
3.41
seam weld
longitudinal weld or spiral weld formed in the pipe welding process
3.42
casing
cylinder installed outside the pipeline to protect the pipeline from exterior damage
3.43
sleeve
two semi-cylindrical shells covering the outside of the pipeline and connected together by welding, etc. to repair pipeline defects
3.44
estimated repair factor (ERF)
ratio of the maximum allowable operating pressure to the safe operating pressure calculated by the metal loss defect evaluation method
ERF=MAOP/psafe
where,
MAOP——the maximum allowable operating pressure;
psafe——the safe operating pressure calculated by metal loss defect evaluation method.
4 General requirements
4.1 Appropriate in-line inspection technology and equipment shall be selected according to the results of pipeline risk assessment and the historical inspection conditions.
4.2 In case of the first application of in-line inspection technology and new equipment or inspection of new defect types, inspection performance verification shall be carried out, which may be performed via traction test or excavation measurement of inspection results.
4.3 The time interval of in-line inspection shall comply with the requirements of GB 32167.
4.4 Pigging operation shall be carried out regularly to keep the pipeline detectable. Pipelines shall be subjected to pigging before in-line inspection.
4.5 The measurement, storage and use of pipeline position data shall comply with national laws and regulations and the confidentiality requirements of pipeline operators.
5 Inspection flow
Prior to the start of inspection, an appropriate in-line inspection flow shall be established. In-line inspection may be carried out according to the recommended implementation flow in Figure 1.
Figure 1 Implementation flow for in-line inspection of pipeline
6 Selection of inspection technology and equipment
6.1 Considerations in inspection tool selection
The purpose and target of the inspection should be determined based on the hazard factors, historical inspection conditions and risk assessment results of pipelines, and the inspection capabilities and performance specifications of the in-line inspection technology and equipment selected shall adapt to the requirements of pipeline inspection. See Annex A for the types and functions of common in-line inspection tools.
When selecting the in-line inspection tools, the factors that shall be considered include but are not limited to:
a) probability of detection (POD);
b) detection threshold;
c) type identification capability;
d) dimensional sizing accuracy;
c) feature positioning accuracy;
f) confidence level;
g) sampling frequency or spacing of sensor;
h) range of wall thickness;
i) speed range;
j) temperature range;
k) pressure range;
l) the minimum curvature radius of the bend that can be passed through;
m) the minimum inner diameter of the pipeline that can be passed through;
n) the length, weight and number of sections of the inspection tool;
o) the pressure difference required to launch and operate the inspection tool;
p) the length of the pipeline that can be inspected in a single operation (co-determined by operating time, pipeline conditions, etc.)
q) size and operating space of pig receiver and launcher;
r) the minimum distance between the valve and the reducer of the pig receiver and launcher;
s) battery type and life;
t) discharge indication when the inspection tool is jammed.
6.2 Performance specification requirements of inspection tool
6.2.1 The performance specification of in-line inspection tool shall specify the ability to detect, locate, identify, characterize and quantify pipeline anomalies and features, including but not limited to the types of anomalies or features, detection threshold and probability of detection (POD), probability of identification (POI), sizing accuracy, positioning accuracy and various restrictions. Specific indexes shall comply with Annex B.
6.2.2 The inspection service provider shall establish the performance specification of in-line inspection tool during operation in specific pipeline by effective statistical methods. See Annex C for the performance specifications of different types of in-line inspection tools.
6.2.3 The performance specification for geometry inspection shall meet the following requirements:
a) the POI of dent, ovality, wrinkle, buckle, bulge and weld shall be greater than 90%.
b) the POI of valve, tee, bend, change of wall thickness and other features shall be greater than 98%.
c) the dimensional sizing accuracy of geometry inspection shall meet the requirements of Table 1, and the feature positioning accuracy shall meet the requirements of Table 2.
6.2.4 The performance specification for magnetic flux leakage inspection shall meet the following requirements:
a) the POI of inner/outer metal loss, dent, eccentric casing, component and weld shall be greater than 90%.
b) the POI of valve, tee, bend, change of wall thickness and other features shall be greater than 98%.
c) the inspection tool shall have the ability to identify and classify the weld anomalies.
Table 1 Dimensional sizing accuracy of geometry inspection
Detection threshold when POD=90% Accuracy when certainty =90%
OD ≤ 406mm 406mm < OD < 1,016mm OD ≥ 1,016mm
Change of wall thickness 1.5mm ±1mm
Ovality 1% ±1%
Dent depth 1%OD ±2mm ±3.5mm ±5mm
Note: OD is the outer diameter of pipeline.
Ovality (%) = (maximum diameter - minimum diameter) / nominal diameter.
Table 2 Feature positioning accuracy of geometry inspection
Axial positioning accuracy when certainty =90% The distance error between feature and reference girth weld is less than ±0.1m
The distance error between reference girth weld and reference point is less than ±1%
Circumferential positioning accuracy when certainty =90% ±15°
d) the inspection tool shall have the ability to identify the failure of joint coating where signs of corrosion have occurred.
e) the dimensional sizing accuracy of metal loss inspection shall meet the requirements of Table 3, and the feature positioning accuracy shall meet the requirements of Table 4.
Table 3 Dimensional sizing accuracy of metal loss inspection
General metal loss
(4A×4A) Pitting
(2A×2A) Axial groove Circumferential groove
Seamless steel pipe Longitudinal (spiral) welded steel pipe Seamless steel pipe Longitudinal (spiral) welded steel pipe Seamless steel pipe Longitudinal (spiral) welded steel pipe Seamless steel pipe Longitudinal (spiral) welded steel pipe
Detection threshold when POD=90% 9%WT 5%WT 13%WT 8%WT 13%WT 8%WT 9%WT 5%WT
Depth accuracy when certainty = 90% ±10%WT ±10%WT ±10%WT ±10%WT -15%/+10%WT -15%/+10%WT -10%/+15%WT -10%/+15%WT
Width accuracy when certainty = 90% ±15mm ±15mm ±15mm ±15mm ±15mm ±15mm ±15mm ±15mm
Length accuracy when certainty = 90% ±10mm ±10mm ±10mm ±10mm ±10mm ±10mm ±10mm ±10mm
Note: WT is the wall thickness of steel pipe, and see Annex D for the definition of A.
Table 4 Feature positioning accuracy of magnetic flux leakage inspection
Axial positioning accuracy when certainty =90% The distance error between feature and reference girth weld is less than ±0.1m
The distance error between reference girth weld and reference point is less than ±1%
Circumferential positioning accuracy when certainty =90% ±5°
6.2.5 The performance specification for WM inspection shall meet the following requirements:
a) the POI of inner/outer metal loss, interlayer, component and weld shall be greater than 90%.
b) the POI of valve, tee, bend, change of wall thickness and other features shall be greater than 98%.
c) the dimensional sizing accuracy of metal loss inspection shall meet the requirements of Table 5, and the feature positioning accuracy shall meet the requirements of Table 6.
Table 5 Dimensional sizing accuracy of metal loss inspection
Certainty Pitting with diameter ≥10mm Pitting with diameter ≥20min General metal loss Axial groove Circumferential groove lamination related to manufacturing or caused by hydrogen induced crack
Detection threshold when POD=90% 1.5mm 1mm 1mm 1mm 1mm 1mm
Depth measurement accuracy 80% Detectable ±0.4mm ±0.4mm ±0.4mm ±0.4mm ±0.4nmm
90% ±0.5mm ±0.5mm ±0.5mm ±0.5mm ±0.5mm
Width measurement accuracy 80% ±10mm ±10mm ±10mm ±10mm ±10mm ±10mm
90% ±12mm ±12mm ±12mm ±12mm ±12mm ±12mm
Length measurement accuracy 80% ±5mm ±5mm ±5mm or ±5% of length ±5mm or ±5% of length ±5mm ±5mm or ±5% of length
90% ±6mm ±6mm ±6mm or ±6% of length ±6mm or ±6% of length ±6mm ±6mm or ±6% of length
Table 6 Feature positioning accuracy of WM inspection
Axial positioning accuracy when certainty =90% The distance error between feature and reference girth weld is less than ±0.1m
The distance error between reference girth weld and reference point is less than ±1%
Circumferential positioning accuracy when certainty =90% ±5°
6.2.6 The performance specification for CD inspection shall meet the following requirements:
a) for cracks with a length greater than 25mm, the ones with a depth greater than 1mm in the base metal or the ones with a depth greater than 2mm in the weld, the POD shall be greater than 90%.
b) the dimensional sizing accuracy of crack inspection shall meet the requirements of Table 7, and the feature positioning accuracy shall meet the requirements of Table 8.
Table 7 Dimensional sizing accuracy of crack inspection
Certainty Measurement accuracy
Depth 90% With depth classification:
< 12.5%WT
(12.5%-25%) WT
(25%~40%) WT
> 40%WT
Length 90% ±10%WT (feature length >100mm)
±10mm (feature length ≤100mm)
Width 90% ±50mm for crack cluster
Table 8 Feature positioning accuracy of CD inspection
Circumferential positioning accuracy when certainty =90% The distance error between feature and reference girth weld is less than ±0.1m
The distance error between reference girth weld and reference point is less than ±1%
Axial positioning accuracy when certainty =90% ±5°
6.2.7 The performance specification for inertial mapping shall meet the following requirements:
a) if the distance between ground reference points is less than 1km, the positioning deviation shall not be greater than ±1m.
b) a single inspection shall identify the bending deformation feature with a curvature radius of less than 400D (D is pipe diameter), and repeated inspections shall identify the bending deformation feature with a curvature radius of less than 2,500D.
6.3 Evaluation of pipeline inspection conditions
6.3.1 Pipeline operator and inspection service provider should jointly collect relevant information of pipelines to be inspected, evaluate the suitability of pipeline inspection, and update and reform the restrictions affecting pipeline inspection.
6.3.2 The pipeline operator shall provide the inspection service provider with a pipeline questionnaire (see Annex E for an example of the questionnaire), which lists the physical features and operating conditions of the pipeline to be inspected, so that the inspection service provider can evaluate whether the pipeline conditions meet the operation condition of the inspection tool, and the evaluation shall at least include the following contents:
a) receiving and launching conditions, including but not limited to:
1) size of pig receiver and launcher: the inspection service provider shall evaluate the applicability of the size of the pig receiver and launcher.
2) operating space: there shall be sufficient operating space for in-line inspection tool during receiving and launching.
b) tee, including but not limited to:
1) whether there is a tee without blocking strip or baffle.
2) center distance of adjacent tees.
c) bend, including but not limited to:
1) the minimum curvature radius of the bend existing on the pipeline.
2) length of straight pipe section between adjacent bends.
3) mitre bend and its mitre angle.
4) continuous bend.
d) valve, including but not limited to:
1) valve type and inner diameter of valve cavity.
2) if there is a check valve, ensure that it can be locked in the fully open position when the pig or inspection tool is operating.
e) pipeline materials, including but not limited to:
1) steel grade and pipe type.
2) distribution and range of pipe wall thickness.
f) operation conditions, including but not limited to:
1) medium type: the medium type affects the selection of inspection technology.
2) medium composition: corrosive medium may damage the inspection tool.
3) medium flow rate: it affects the operation speed of the inspection tool, total time and accuracy of inspection. When the medium flow rate does not meet the conditions, it may be considered to adjust the throughput or enable the speed adjustment function of the inspection tool.
4) medium temperature: the medium temperature shall not exceed the temperature range that the inspection tool can bear during operation.
5) operating pressure: most inspection tools have applicable pressure range, too low operating pressure or too low pressure difference in front and at the back of the inspection tool will lead to insufficient driving force of the inspection tool, and too high operating pressure exceeding the pressure resistance design will lead to failure of the in-line inspection tool.
g) other restrictions, including but not limited to:
1) inner coating of pipeline.
2) pipe cleanliness.
3) inner diameter change of the pipeline.
4) probe implanted into pipeline.
5) large drop of pipeline and crossing pipe bridge.
6) mechanical support of pipeline and off-design crossing.
7) hydrates and spontaneously combustible substances in the pipeline.
6.3.3 The pipeline operator shall provide pipeline construction related to inspection, maintenance information and historical inspection results.
6.3.4 The inspection service provider shall preliminarily evaluate the detectability of the pipeline according to the information of the pipeline questionnaire.
6.3.5 The inspection service provider shall, with the cooperation of the pipeline operator, conduct site survey and final evaluation of the contents in the pipeline questionnaire.
6.3.6 The pipeline operator shall transform or replace the pipeline and its ancillary facilities that do not meet the operation conditions of the inspection tool.
6.4 Verification of performance specification of inspection tool
After the inspection tool is selected, the performance specification of the inspection tool shall be verified. See Clause 1 for specific requirements for verification.
7 Inspection scheme
The inspection scheme shall be prepared according to the actual situation and approved by the pipeline operator, and the scheme shall at least include the following contents:
a) basic situation of pipeline.
b) evaluation on operation conditions and operation process requirements.
c) site survey result and risk analysis, special protective measures shall be formulated when the sulfur-containing pipeline receives the inspection tool.
d) inspection organization and inspection procedure.
e) requirements for inspection tracking, marking and ground measurement (if portable ground tracker is used to track the inspection tool, site survey shall be carried out for whole-line marking points in advance, of which the interval shall not exceed 1km, and it may be added and set in special sections where large rivers cross).
f) inspection schedule.
g) pigging scheme.
h) operation scheme of inspection tool.
i) data downloading requirements.
j) acceptance criteria of inspection results.
k) excavation verification requirements.
l) HSE operation requirements.
m) emergency response plan.
8 Inspection implementation
8.1 Operation plan
The pipeline operator and the inspection service provider should jointly determine the in-line inspection plan, focusing on the following factors:
a) inspection implementation time.
b) operation process conditions.
c) human and material resources.
d) Site condition.
e) health, safety and environmental factors.
8.2 Marking and tracking
8.2.1 Selection of reference point
8.2.1.1 Ground pipe locater shall be used to patrol the line and select the reference point in the pigging and inspection operations.
8.2.1.2 The reference points should be located with easy access and certain intervals (usually no more than 1km) near the permanent marks such as pipeline mileage posts.
8.2.1.3 Reference points should be added and set at large drop or valve chamber, crossing, turning and other special positions.
8.2.2 Measurement of reference point position
8.2.2.1 The reference point position shall be measured, recorded and maintained as part of the permanent data of the pipeline.
8.2.2.2 It should be installed at the reference point just above the pipeline with permanent magnet as a permanent mark.
8.2.3 Tracking and monitoring
8.2.3.1 Before the start of tracking, the reference points shall be listed, and a tracking plan shall be made in advance according to the position and quantity of reference points.
8.2.3.2 The inspection service provider shall provide a corresponding number of above-ground markers according to needs of the site, and ensure that each marker functions normally.
8.2.3.3 The inspection service provider shall train the tracking personnel in the use of above-ground markers in advance, and ensure that all tracking personnel can operate correctly.
8.2.3.4 Before pigging and inspection, the tracking personnel shall patrol the marking points of the whole line in advance, set the tracking entry route, and organize simulated tracking if necessary.
8.2.3.5 After the inspection tool is launched, the tracking personnel hold the above-ground marker to track according to the preset reference point. When the inspection pipeline is long, the tracking can be carried out in an alternating way. In areas difficult for personnel and vehicles to enter, the tracking marker can be buried in advance at the reference point.
8.2.3.6 When the inspection tool passes through important reference points such as valve chamber and crossing, the tracking personnel shall report the operation state in time.
8.2.3.7 In case of special circumstances, the tracking personnel shall immediately report to the dispatcher. If it is found that more than three consecutive above-ground markers are not triggered when tracking, and the pig/inspection tool cannot be found to pass through via vibration, the corresponding emergency response plan shall be started to find the specific position of the inspection tool or pig in time.
8.3 Pigging
8.3.1 Pigging shall be carried out before in-line inspection, and in-line inspection pigging is generally divided into two stages, the first stage is gauge pigging and the second stage is enhanced pigging.
8.3.2 The pigging operation flow shall be implemented according to Annex F and meet the requirements of SY/T 5536 or SY/T 5922.
8.3.3 When selecting pigs, the materials, pigging capacity and interference of different types of pigs shall be considered.
8.3.4 The pig shall be equipped with tracking instruments. The pig tracking scheme shall be set and tracking and monitoring shall be organized according to the production requirements.
8.3.5 During the gauge pigging stage, pigs with passability not lower than that used for routine maintenance can be used for pigging, and the pipeline passability can be judged by installing gauge plate. The gauge plate should be aluminum round plate, and the diameter shall not be less than the minimum passing diameter of the inspection tool. If the gauge plate is damaged, the cause of the damage shall be analyzed in time. If it is determined through analysis that the damage is caused by large deformation of the pipeline, the inspection service provider shall evaluate whether the deformation of the pipeline meets the passing conditions of the inspection tool. If the inspection tool can't pass and can't locate the accurate position of the deformation point after evaluation, geometry inspection shall be carried out.
8.3.6 Straight plate, steel brush, magnetic force and other pigs are used for pigging at the enhanced pigging stage until the requirements of in-line inspection are met, and following requirements shall be met:
a) before the inspection tool is put into operation in the pipeline without inner coating, the steel brush and magnetic pig should be operated at least once, and in the pipeline with inner coating, the appropriate pig shall be selected according to the situation.
b) the weight of debris removed is less than 5kg, or the weights of debris removed by two consecutive times of pigging are equivalent and meet the inspection requirements.
8.3.7 When it is possible to remove FeS or other spontaneously combustible substances, protective measures such as water injection and spraying shall be taken for the pig receiver before opening the blind plate.
8.4 Operation of inspection tool
8.4.1 Launching of inspection tool
8.4.1.1 The inspection tool shall be commissioned before launching to ensure the normal operation of each system.
8.4.1.2 The transmitting and tracking device shall be inspected to ensure its integrity before inspection tool launching.
8.4.1.3 Refer to Annex F for the launching process of the inspection tool which shall comply with the relevant operation procedures for pipeline operation.
8.4.1.4 During the operation of the inspection tool, it shall be tracked and monitored according to the provisions of 8.2.3.
8.4.2 Receiving of inspection tool
8.4.2.1 Refer to Annex F for the receiving process of the inspection tool which shall comply with the relevant operation procedures for pipeline operation.
8.4.2.2 When it is possible to remove FeS or other spontaneously combustible substances, protective measures such as water injection and spraying shall be taken for the pig receiver before opening the blind plate.
8.4.2.3 After the inspection tool is taken out of the pig receiver, it shall be visually inspected and cleaned.
8.4.2.4 Download and back up inspection data
8.4.2.5 The integrity of data shall be inspected, including:
a) whether the signals of each channel are clear and complete.
b) whether the data of the above-ground marker is complete.
c) evaluating whether data integrity is acceptable.
8.4.3 Inspection operation report
The inspection operation report shall be submitted after the inspection is completed, which should include the following contents:
a) name of pipeline.
b) operation date.
c) type of inspection tool.
d) pipeline diameter and operation distance.
e) all important changes made to the inspection tool.
f) operation average speed and speed curve.
g) success or failure of the operation, and analysis of the failure causes and re-operation measures if it fails.
9 Submission of inspection results
9.1 General requirements
9.1.1 The pipeline operator and the inspection service provider shall agree on the requirements for submitting the inspection results in advance. If the inspection items adopt multiple inspection technologies (such as magnetic flux leakage and ultrasonic inspection tool) or multiple functions are combined on one inspection tool (such as magnetic flux leakage and inertial mapping combined inspection tool), the pipeline information obtained by different types of inspection tools shall be aligned and combined in the same report and the same anomaly (defect) list. See Annex G for specific requirements for the inspection report.
9.1.2 The inspection service provider shall provide the electronic inspection report, which shall include the following information:
a) overview of inspection works, including pipeline defects
b) performance specification of inspection tool
c) inspection time
d) operation data of inspection tool
e) list of pipeline features
f) anomaly list
g) statistical data and summary
h) ERF and defect evaluation method
i) excavation list of severe defect points
j) correspondence between ground reference points and relatively permanent marks on pipelines (such as inspection post, etc.)
9.1.3 The following operation data of inspection tool shall be given in the report, and each inspection tool shall be described separately:
a) data sampling frequency or spacing
b) detection threshold
c) report threshold, if both parties do not specify, use the feature when POD=90%
d) operation speed curve, pressure curve and temperature curve of the inspection tool
e) statistics of damaged sensors
f) echo loss statistics if ultrasonic inspection tool is used
9.1.4 The anomaly feature list file shall be provided, and the hard disk copy of the inspection data and the customer management software shall be provided. The functions that the software shall have include but are not limited to:
a) showing the initial data.
b) showing the absolute distance and relative distance of the feature.
c) showing the clock orientation of the feature.
d) measuring the axial distance and circumferential distance of any two points on the pipeline
e) generating the clock orientation of the intersection of spiral weld (longitudinal weld) and girth weld.
f) generating the excavation list
g) quickly positioning and inquiring based on girth weld number or inspection mileage.
9.2 Requirements for geometry inspection report
The classification statistical results of geometric deformation shall be given in the form of data and statistical graph, and the specific contents are as follows:
a) statistical data shall include:
1) the quantity of all geometric deformation points;
2) the quantity of all dents;
3) dent quantity with 1%OD≤depth<6%OD;
4) dent quantity with 6%OD≤depth<9%OD;
5) dent quantity with depth≥9%OD;
6) quantity of total ovality;
7) ovality quantity with 1%OD≤deformation amount<5%OD;
8) ovality quantity with 5%OD≤deformation amount<10%OD;
9) ovality quantity with deformation amount≥10%OD;
10) quantity of all bulges;
11) quantity of all wrinkles;
12) quantity of all buckles;
b) statistical graph shall include:
1) distribution diagram of all deformation points along pipeline mileage;
2) clock orientation distribution diagram of all dents along pipeline mileage.
Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 Inspection flow
6 Selection of inspection technology and equipment
6.1 Considerations in inspection tool selection
6.2 Performance specification requirements of inspection tool
6.3 Evaluation of pipeline inspection conditions
6.4 Verification of performance specification of inspection tool
7 Inspection scheme
8 Inspection implementation
8.1 Operation plan
8.2 Marking and tracking
8.3 Pigging
8.4 Operation of inspection tool
9 Submission of inspection results
9.1 General requirements
9.2 Requirements for geometry inspection report
9.3 Requirements for metal loss inspection report
9.4 Requirements for centerline mapping report
9.5 Requirements for bending strain report
9.6 Requirements for submission time
10 Verification of inspection results
10.1 General requirements
10.2 Measurement methods of defects
10.3 Verification report
11 Verification of performance specification of inspection tool
11.1 General requirements
11.2 Based on historical data
11.3 Based on the traction test
11.4 Based on excavation verification
11.5 Single-point verification measurement
11.6 Inspection for performance specification based on statistics
12 Project completion data
13 Inspection data management
13.1 Inspection data
13.2 Inspection information
13.3 Comparison of inspection data and use of corrosion growth rate
14 Requirements for adaptability of newly-built pipelines
15 Inspection risk control and emergency disposal
15.1 General requirements
15.2 Preventive measures
15.3 Emergency disposal
16 Requirements of inspection service provider
16.1 General requirements
16.2 Requirements for operating personnel’s capability
16.3 Requirements for data analysis personnel’s capability
Annex A (Informative) Types and functions of inspection tools
Annex B (Normative) List of performance specifications of inspection tools
Annex C (Informative) Examples for performance specifications of inspection tools
Annex D (Normative) Definition of metal loss types
Annex E (Informative) Example of pipeline questionnaire
Annex F (Normative) Work flow of pig receiving and launching
Annex G (Informative) Example of inspection report
Annex H (Informative) Verification methods and processes of defects
Annex I (Informative) Examples for verification of performance specifications of inspection tools
