Presentation on
CASE STUDIES – SAFETY IN PIPELINE
OPERATION
By
RAJESH UPRETY,
ADDITIONAL DIRECTOR (PIPELINES)
Oil Industry Safety Directorate
Date: 18.04.2015
NARMADA RIVER –
SNAPPING OF PIPELINES
LOCATION MAP
SCHEMATIC VIEW OF THE NARMADA RIVER SITE
TOTAL NO. OF PIPELINES PASSING THROUGH
NARMADA RIVER
S.No. Pipeline Operator Pipe Size
Remarks
(1)
Reliance (RGTIL)
Natural Gas
48” OD x 1.000” WT
(25.4 mm), API 5L X70
Gr.
Line is intact
(2)
GAIL India
Natural Gas
30” OD x 19.1/11.9 mm
WT, API 5L X 70 Gr.
Snapped & burst
(3)
Reliance
Industries 26” OD x 0.500” WT, API Snapped & burst. Pipe
Limited (RIL)
5L X 60 Gr.
has got stuck in the
Ch. 29.150 KM (NG)
nearby electrical tower
Natural Gas
(4)
Reliance
Industries 24” OD x 0.500” WT API Snapped & burst.
Limited (RIL)(NG)
5L X 60 Gr.
Ch. 29.150 KM
TOTAL NO. OF PIPELINES PASSING THROUGH
NARMADA RIVER
S.No. Pipeline Operator
Pipe Size
Remarks
(5)
Gujarat State Petronet 24” OD x 0.688” (17.5 About 100 m pipeline is
exposed.
Ltd., (GSPL – NG)
mm) WT, API 5L X 60 Gr.
Ch. 17.000 KM
(6)
ONGC (Ch. 14.200 KM) 8.625” OD x 0.375” (9.53 Leakage in line
CRUDE OIL
mm) WT, API 5L X 46 Gr.
(7)
IOCL
(Amod
Pipeline)
(8)
ONGC (OPAL)
Naptha
Hazira 12.75” OD x 0.219” WT, Line is intact
API 5L X 60 Gr.
12.75” OD x 0.25” WT, API Under construction
5L X 46 Gr.
ROOT CAUSE OF THE INCIDENT
S.No
CAUSE OF THE INCIDENT
(1)
It was a natural calamity. Unprecedented sudden floods due to heavy rains
and large quantity of discharge of water from Sardar Sarovar Dam.
(2)
The river bank (south side) was not reinforced, which resulted in heavy soil
erosion.
(3)
Removal of plants and vegetation during the construction of Electrical
Transmission Tower of Torrent Power close to the river bank, which has
resulted in loosening of the parent soil.
(4)
Irrigation Dept. did not provide any prior warning before release of abrupt
water discharge in such a large quantity.
(5)
Soil erosion is a gradual process, which takes number of years. Pipeline
Operators should closely monitor such behavior of the river course and the
adjoining banks on a regular basis.
ROOT CAUSE OF THE INCIDENT
S.No
CAUSE OF THE INCIDENT
(6)
It was a natural calamity. Unprecedented sudden floods due to heavy
rains and large quantity of discharge of water from Sardar Sarovar
Dam.
(7)
Because of the erosion of the soil from the river bank, pipe line,
which was buried in the ground became exposed and pipe line in the
eroded portion became unsupported. Due to the force of water on
this exposed portion of pipe line, it started oscillating and finally one
of the pipelines got snapped due to heavy oscillation effect in
hanging pipe line section. The velocity of water and turbulence in the
river was extremely high at the time of incident.
REVIEW OF CHANGE IN DESIGN & ENGG.,
IF ANY
S.No DESCRIPTION
(1)
No changes are required w.r.t. design and engineering of pipeline,
however, the extent of HDD shall be increased based on the present
situation of this particular river crossing, to avoid the future flood
scenario.
(2)
Provision already exists in the codes as per clause no. 11.7.3 of OISD
standard 141 for oil pipelines and 10.6.4.1 of OISD 226 for Gas pipelines
that ‘Special considerations shall be required for river crossings which are
characterized by their perennial nature, meandering course, steep and
potentially erodible banks, potentially scouring bed, large erodible flood
plain and wide water course (high flood level) both during the design and
installation of such crossings’.
IMPORTANT POINTS PERTAINING TO
IRRIGATION DEPARTMENT
S.No
DESCRIPTION
(1)
Regarding future trend and width of the Narmada River, It was informed
that it is not possible to predict the future scenario. However they
confirmed that only the Highest Flood Data can be made available by
Irrigation Deptt., which shall be useful for deciding the length of the HDD.
(2)
Presently there is no controlling device (Gate/ Sluice Valve) provided at
Sardar Sarovar Dam, as a result of which there was no control to the flow
of water. Now it has been told that there is a proposal to provide a gate
before next monsoon. This will enable to control the flow, thereby
minimizing the impact at site due to release of sudden discharge of water.
(3)
Any construction work near the river bank should be discouraged as this
leads to loosening of the parent soil due to removal of plant and
vegetation. In this case an Electrical Transmission Tower was constructed
near the river .
IMPORTANT POINTS PERTAINING TO
IRRIGATION DEPARTMENT
S.No
DESCRIPTION
(4)
In case there is any planning to release sudden water from the
dam, same should be shared with all the pipeline operators by
Irrigation Department.
(5)
Close liaisoning and co-ordination to be maintained with all the
pipeline operators.
FINAL RECOMMENDATIONS
S.No
DESCRIPTION
(1)
Reinforcement of the river banks must be carried out in order to arrest
the soil erosion. Pre-installation surveys shall be carried out to establish
the prevailing river bank profiles including collection of data on fluvial
geomorphology and channel processes for design purposes.
(2)
Execution methodology of bank protection works shall be designed/
implemented in such a manner that the normal operations of the
pipelines are not hampered.
(3)
Fresh hydrological survey needs to be performed based on the recent
flood discharge and hydraulics to arrive at new scour profile. Additionally,
topographical and geotechnical investigations shall be performed to firm
up the extent of HDD length.
FINAL RECOMMENDATIONS
S.No
DESCRIPTION
(4)
New HDD shall be performed for the damaged pipelines. HDD length of all
the damaged pipelines must be kept sufficiently large, which shall be based
on the topographical survey of the site.
(5)
There should be a close co-ordination and liaisoning between all the
Pipeline operators and irrigation department.
(6)
The distance between two sectionalizing valves across the Narmada river
must be kept immediately (as close as possible) near the upstream and the
downstream bank of the river and these valves must be remote operated so
that in case of an emergency, valves can be closed immediately and the
section can be isolated thus minimizing the quantum of product loss and
minimizing the environmental impact.
FINAL RECOMMENDATIONS
S.No
DESCRIPTION
(7)
Disaster Management Plan should be reviewed to take care of such an
emergency.
(8)
Irrigation Deptt. should not allow construction of any structures near the river
bank as these tend to make the parent soil loose due to uprooting of plant
and vegetation.
(9)
All pipeline operators must be focused on such river crossings and closely
monitor the soil erosion pattern regularly on both the banks and take
immediate corrective measures by way of providing reinforcement to the
bank or increasing the length of the HDD so that such accidents can be
avoided.
(10)
Whenever, such incidents take place, it should be immediately brought to the
notice of OISD in the prescribed format. In this case, none of the affected
operators gave the information to OISD.
FINAL RECOMMENDATIONS
S.No
DESCRIPTION
(11)
During the second floods which took place on 25-27th September 2013,
it was observed that about 70 M of the 24” OD NG line of M/s GSPL was
hanging (photo enclosed) and the line was swinging up and down, but
the line was kept in operation. This is a very serious issue.
(12)
Proper health monitoring must be done for all those lines which are not
damaged before putting them back into operation.
GAIL – TATIPAKA
CATASTROPHIC FAILURE
DUE TO CORROSION
(FIRE & EXPLOSION
INCIDENT)
NATURAL GAS PIPELINE
Leak/Burst site
Date/Time of incident
27th June 2014 at
about 0545 hours
No. of fatalities
22
Operating pressure
42 to 45 Kg/cm2
Design pressure
72 Kg/cm2
Pipeline size and grade
18” OD API 5L X60
Grade
RIVER BRIDGE
SV-1
SV-2
18" (API 5L X-60)
ORIGINATING
STATION
SV-5
SV-4/ I P
HIGHWAY X-ING
SV-3
(PIGGING STATION)
(CANAL)
POWER PLANT
RIVER X-ING
SV-6
SV-7
SV-8
12
ANALYSIS / OBSERVATIONS OF THE FIRE
INCIDENT
• Cross country pipeline – supplying Natural Gas to power
plant
• The pipeline was being operated at a lower flow rate and
lower pressure w.r.t. the design parameters.
• Pipeline was transporting wet gas while it was originally
designed for transporting dry natural gas.
• The gas contained CO2 and some traces of Sulphur.
• Leakage took place at the lowest point where the pipeline
was crossing a canal at 6 o’clock position.
25
FURTHER OBSERVATIONS OF THE FIRE
INCIDENT
• It was raining on the day of the incident, so it is inferred
that vapour cloud formed due to heavy weather.
• A tea stall owner. who turned on the stove in the morning,
possibly provided the source of ignition.
• There has been a history of previous leaks near the place of
accident.
26
ROOT CAUSE OF THE FIRE INCIDENT
• Leak due to internal corrosion – presence of CO2 led to
formation of H2CO3.
• During earlier repairs external coating got damaged
resulting in external corrosion.
• Improper pigging – foam pig used instead of scrapper pigs.
• Pig residue analysis not carried out.
• IPS carried out in 2010 - Maximum metal loss reported in
IPS is equivalent of 50% of wall thickness.
• Use of wet natural gas instead of dry natural gas.
• Not using corrosion inhibitor.
27
RECOMMENDATIONS
• Proper cleaning pigging to be carried out regularly followed by pig
residue analysis.
• Instrumented pig survey to be carried out regularly and the anomaly
rectification to be carried out as per the recommendations .
• Proper procedure to be made for repair of pipeline.
• Any change from the initial change should be routed through a
management of change procedure after proper technical analysis.
• Corrosion inhibitor to be used in the line as per requirement.
• In addition to OFC communication there should also be another stand
by mode of communication.
• Proper maintenance and inspection practice to be followed.
28
RECOMMENDATIONS
• Effective CP monitoring to be carried out.
• Effective Line patrolling to be carried out using modern gadgets such
as GPS, GIS based decision support system etc.
• Leak detection system should be provided in the mainline.
• Health monitoring of all non-piggable lines to be carried out using
Direct Assessment
• Wherever the pipe elevation is changing draining drastically from lower
to higher elevation , an additional pigging station to be provided for
removal of the condensate.
29
PHOTOGRAPHS
•
30
PHOTOGRAPHS
31
PHOTOGRAPHS
32
GAIL – SURYAPET FATAL
INCIDENT)
STUCK PIG
PIG
RESIDUE
VENT/
DRAIN
VALVE
MAINLINE
38 Kg/cm2
Pig came out
from here
• Pyrophoric iron in contact with air
liberated heat which resulted in explosion
of LPG-air mixture inside the barrel
resulting in propulsion of pig at a very
high force. The persons standing in front
of the open door of the barrel were hit by
the pig which resulted in fatality & injury.
• Draining of entrapped LPG inside the
barrel between barrel valve & pig could
not be done due to absence of drain or
vent.
• A pig train was being used consisting of
cups, brush and magnetic pig all coupled
together - this is a unique case where pigs
have been tied together & not the
industry practice.
• The length of the scrapper receiving barrel
was more.
• All the drain and the vent points were
near the quick opening-quick closure door
of the barrel.
• Iron content (Fe2O3) was very high (>90%),
which indicates that health of the pipeline
is not good and there appears to be
considerable metal loss due to internal
corrosion.
• The residue analysis report reveals that
there is a presence of 90.99% by mass of
iron as Fe2O3 and 5400 ppm of sulfur. The
health assessment of the entire line is
required to be carried out.
• Health assessment of the LPG pipeline
must be carried out since the pig residue
indicate considerable high iron content
(90.99%) indicating metal loss due to
corrosion.
• An additional vent & drain point with
pressure gauge shall be provided in the
neck portion of the barrel to drain the HC.
• Pig train must not be used with all pigs in
tied condition. This is not a usual practice.
• Magnetic pigs should be used only when it
is ascertained that the iron content is
nominal.
• While receiving the pigs, it shall be
ensured that proper venting has been
carried out between barrel body valve and
the pig to ensure that the barrel is free
from any hydrocarbons.
• While receiving the pig it shall be ensured
that no person is standing directly in front
of the barrel.