Presentation on theme: "by Rajan K Pillai, CEO ISPRL"— Presentation transcript:
1by Rajan K Pillai, CEO ISPRL Safety Measures Adopted in Underground Cavern Storage of Crude Oil to Prevent Disastersby Rajan K Pillai, CEO ISPRL31st January 2014
2CONTENTS OF PRESENTATION Underground Rock caverns for storage of hydrocarbons in IndiaRisks and Hazards in Underground CavernsConstruction Risks.Operations Risks.Mitigation methodsConstruction phaseOperations phase
3Underground Rock caverns for storage of Hydrocarbons in India
4Isometric drawing of SALPG Cavern Access Ramp (AR)Upper Connection (UC)Intermediate connection (IC)Upper Shaft Connection (USC)Access Shaft (AS)Operation Shaft (OS)Lower Shaft Connection (LSC)Water Gallery – Operation Shaft Connection (WOC)Water Gallery – Access Shaft Connection (WAC)Water Curtain Gallery (WCGSump which houses the submersible pumpsLower connection (LC)Operation Shaft is 201 meters deep
5The Isometric View of the Visakhapatnam UG Facilities The view shows the various parts of the facility which includes access tunnels, water curtain galley, interconnection tunnels & shafts.Capacity is 1.33 MMTTotal tunnelling including shafts exceeds 7 kilometres5
6The main galleries are 913 m long Isometric View of Mangalore UG FacilitiesCapacity is 1.5 MMTThe main galleries are 913 m longTotal tunnelling including shafts exceeds 9.2 km.
7Isometric View of Padur UG Facilities The Padur project capacity is 2.5 MMT. The total excavation is in excess of 36.8 lakh cu m. The facility has 6 storage galleries that are 700 m long and 2storage galleries thatare 650 m long.Entire excavation has been completedA jumbo jet in the foreground for comparisonTotal tunnelling including shafts exceeds 13.7 km(only top heading).
8Typical Cross Section of the Main Cavern The height of the caverns is almost equivalent to a ten storey building7 mTop HeadingBench 17 mBench 2VariesBench 3
9A view of the Padur Cavern Gallery The galleries are 30 meters tall and 20 meters wide. There are eight galleries. Six galleries are 700 meters long and three are 650 meters long. This photograph is of one of the completed 700 m galleryPhotograph of a gallery in the Visakhapatnam Cavern
10The excavated rock debris can fill 2.5 million standard 10 ton trucks Quantum of Excavation in ISPRL CavernsItemVizagMangalorePadurTotalAccess & Connect. tunnels (meters)1632184734296908Water Curtain Tunnels (meters)1804356038819245Main Cavern (meters)32503572563212454Shaft lengths (meters)4052325801217Total Chainage (meters)709192111352229824Borehole Nos2754895141278Borehole length (kilometers)17.232.026.976.1Excavated qty in Million tons22.214.171.1241.5The excavated rock debris can fill 2.5 million standard 10 ton trucks
11Approx Quantum of Material used in ISPRL Projects ItemVisakhMangalorePadurTotalConcrete in Cu. m5046435862914231,77,749Shotcrete in Cu. m37395217783507294,245Rock Bolts in tons23601981.722266,568Reinforcement steel in tons18101565699110,366Explosives used in tons2330210038658,295The material would required a huge transport fleet for movement from one spot to the other within the sites. In addition to the materials, workforce also needs to be moved
12Comparison of the Excavation Progress Curves Projects were started on different dates, but for comparison, zero dates have been matched
14Geological Risks- During Construction…….Slide1 Over Breaks and Rock fallsOver breaks and rock fall are major safety concerns during construction and can cause fatalities and can drastically slow down progress.
15Since this fault was below the bench it could not be identified. This bench was excavated
16When the bench was removed the rock wedge started sliding Wedge on the wall started slidingWhen the bench was removed the rock wedge started sliding
17Almost 10,000 tons of rock came crashing down and resulted in one fatality.
18Area of brittle fracture The triangular block which slid downSmooth face
19Man standing near rock slide area Weakness zone, consisting of highly sheared and disintegrated material
21Geological Risks- During Construction…….Slide3 Water bearing zones or aquifers zones could result in large water ingress into the caverns or shafts. Such a problem was encountered in the SALPG cavern project.Water ingress into shaftUnderground Aquifers
22Large seepage of water into the Padur cavern during construction
23Traffic Hazards- a major concern during construction .Large number of equipment –required for excavation of the caverns. Movement of equipment adds to the risks
27Explosives handling- a concern during construction In ISPRL the quantum of explosives that have been used is huge. We have use approx 8300 tons of explosives in our projects.When handling such large quantities of explosives, there is the risk of accidental blasts or misfires.There is also the risk of the explosives being pilfered during their transportation and use and thereafter being used for undesirable activities.
28Vibration due to blasting – another concern. The vibrations can be large if the quantum of explosives used is large.Vibrations can cause damage to the surrounding rock and effect the stability of the cavern.Vibration can also cause damage to surrounding surface structures.Blast induced ground vibrations can create social problems as they could disturb the people residing in the vicinity
29Fumes and dust – a health hazard Air borne dust particles when inhaled into the lungs can lead to various diseases, like bronchitis.There is particular concern that silica dust can lead to cancer. Crystalline silica is a common mineral present in sand stone, quartz and many other rocksDuring blasting operation fumes are produced. These fumes can be harmful to humans working inside the tunnels.The oxygen levels in the cavern can become low after the blasting operation and therefore poses a health hazard
30Risks During Operation Phase Loss of ContainmentDue to hydro geological reasons.Due to sabotage/failure of aboveground facilitiesIntermingling of different grades of crude oil.Fire/Explosions within caverns due static electricity discharge.
32Mitigation methods-Construction Phase …Slide 1 Rock boltsTo ensure there is good stability of the cavern, rock bolts need to be installed and shortcrete applied. Poorer the rock strata, larger is the support requirement.Shotcrete
33Large number of optical targets installed in the caverns Large number of optical targets installed in the caverns . The bright spots are the optical targetsMonitoring of the movement of the walls of the cavern using optical targets
34Pre-Grouting in excessive water bearing zones Pre-Grouting involves drilling a number of holes on the face and pumping cement paste under pressure into them till sealing is achieved.High permeability and water bearing strata could result in higher grouting and slow excavation progress.
35Mitigation Methods – for Traffic Hazards The cavern access tunnels and junctions to be well designed.Only specialized equipment to be used for evacuating muck (equipment with all safety features)Drivers to be imparted specialized training for underground works.Tool box talk to be made mandatory before start of work.Housekeeping to be one of the important requirements in contract management.Good rewards and punishment system should be planned .
36Mitigation Methods – for explosives handling Obtaining all applicable Legal Permissions as per “The explosive Act 1884” and Explosive Rules 1983.Putting in place a well defined explosive handling procedure and clearly describing steps to be followed during transportation, storage and handling of explosives.Ensuring qualified & authorized personnel only handle the explosives.Reconciliation of all explosive material and authentication of reconciliation statement by Magazine In charge.
37Mitigation Methods – for excessive vibration The vibration problems can be best controlled by having properly designed blast patterns. The number of blast holes, their length, amount of explosives to be charged and the detonation type.Once these parameters are controlled properly, they can reduce vibration levels drastically.After ensuring properly designed blast patterns, ensure the vibration levels are monitored on a regular basis.The site to be trained to ensure that only smooth blasting techniques are followed at all times inside the caverns.
38Mitigation Methods – for fumes and dust Huge motor driven air blowers installed at the entrance of the caverns to pump in fresh air to the blasting faces and cavernsHuge flexible ducts inside the access tunnels which carry air to the blasting faces and caverns
39Mitigation Methods – Loss of containment PiezometersWater tableIt is important that during the operation phase, the water table is monitored at all times
40Mitigation Methods – Failure of AG piping Failure of pipeline. LPG starts to leakWaterColumn of water acts as a seal and shuts off cavernGasLPG
41Separation of different products to be stored Water Curtain BoreholesWater curtain tunnelsMean Sea Level(MSL)Storage Caverns
42Mitigation Methods – For fires /explosions The caverns for products other than LPG are intertized by filling the vapour spaces with either nitrogen or flue gases. The oxygen content reduced to less than 8% . This will avoid any explosions caused by static electricityNitrogen or flue gasCrude oilStorage Caverns
43We have Miles to go Thank You Measures Adopted for Monitoring the SAFETY & DISASTERS in Underground storage cavernsWe have Miles to goThank You