Transport (road, water and air) considerations for drilling operations
1 Road transport
Subject to local regulations, all vehicles (such as pick-ups, stake-side trucks, prime-mover/trailers, oilfield trucks, tankers and vacuum trucks) should use diesel fuel. Small gasoline stocks for one or two vehicle are a safety hazard, because gasoline is inherently more hazardous and there is a risk of using the incorrect fuel in a vehicle. Gasoline is also more tempting for potential thieves.
In any contract for road transport services it is recommended to include the provision of a workshop vehicle and of a despatcher/liaison man.
Contractor standards
In any operation, on- or off-shore, there will be a requirement for road transport. Even is an international contractor can be used for major jobs, local contractors should be identified, inspected and tested during the preparatory phase. Depending on the standard of the vehicles, and the type of contract, it may be necessary to give a contractor an incentive to bring his operations up to an acceptable standard.
If the contractor is treated as a common carrier with an agreement to move material from A to B by whatever means he sees fit, the company is not responsible for the conduct of the movement. If on the other hand specific vehicles are contracted, the company is responsible for it.
The above standards, will apply whether the local transport is contracted directly by the company, or indirectly via the drilling contractor. The company should always be familiar with the available contractors, and approve their use.
Route surveys
This survey should be undertaken prior to any operation to check on bridges, narrow passes, trees causing an obstruction, sharp bends, and overhead power/telephone cables.
Relevant Government agencies should be contacted to ascertain the regulations with respect to axle loads and/or other critical restrictions.
If bridges are old and the safe working load can’t be estimated, the solution is to observe what weights are frequently passing over them in practice, and to restrict loads (including contractor’s) to the same weight. If the restriction is unacceptable, consideration will be given to installing a new bridge or constructing a new road which does not require a bridge.
Telephone and domestic power cables should not cause problem, they can be lifted, or cut temporarily and buried. High voltage cables can cause problem for high loads, even when there is enough clearance (discharges through damp air). It may be easier to lower the road, or divert, than to raise the power line. It may also be possible to arrange with the authorities to interrupt the supply for a limited time during an off-peak period for the passage of specific loads.
Road safety
A high percentage of lost-time accidents and fatalities are road transport related. To ensure a safe operation a set of guidelines should be established, and the importance of continuing compliance with them must be emphasized at every opportunity. Appropriate road safety clauses should be included in every contract in which any driving is required, even when it is not part of the main scope of work. A sample set of guidelines are presented in appendix x.
2 Water transport
General
Check as soon as possible the local regulations concerning the country of registration of vessels which may be used, and regulations concerning their operation and crewing. This has to be done before going out to tender. The regulations are likely to be more restrictive for inland waters like rivers.
There are likely to be regulations concerning the carrying of pilots at certain stages, but it may be possible to obtain a dispensation. The procedure should be initiated as soon as possible (probably when the vessels and masters names are known). It may also be possible to comply with regulations by taking a certificated pilot onto the local staff if there is one available.
Whatever the regulations it is important to have good relations with local ship-owners, and to give them as much business as possible. They can be of invaluable assistance in dealing with the local maritime authorities, but can also create a lot of problems for the company.
Ocean-going tugs
These are required for mobilising an offshore drilling unit (excluding drill ships) and may well be involved in land drilling operations for mobilising the rig and for towing barges with equipment.
Rig mobilisation should be done by the drilling contractor on a lump-sum basis, but it may be possible to optimise by using the anchor handling/supply vessels for ocean tows, or by combining the towing contracts for the contractors rig and for the Company equipment/consumables.
The possibility of double tows should be considered, if appropriate. This will be decided by the vessel owners' insurers. Different companies may have different views, and this may have an effect on the contract price. This point should be raised in the invitation to tender rather after the contract has been awarded.
Anchor handling/tug/supply vessels
Two are normally required for an offshore operation. The minimum horse-power and/or bollard pull will be specified by the surveyors of the rig insurers.
Bulk transfer hose connections should be compatible with those of the drilling unit, and that the pumping/blowing heads available are sufficient for the specific drilling unit. The various bulk capacities should also be compatible with the rig capacities and consumption.
The UKOOA/BOSVA (U.K. Offshore Operators Association/British Offshore Supply Vessel Association) "Code of Conduct for Supply Vessel Operations at Offshore Installations" is a useful guide to supply vessel operations.
Consider having oil-spill equipment on the supply vessels.
Barges
Barges are more likely to be used in an onshore rather than an offshore operations.
They can be used for an ocean tow followed by a beach landing at a location where there are no off-loading facilities for ships. They are also very convenient for an ocean tow followed by delivery to a materials base located on a river - or even to act as floating storage on the river and/or pick up point for underslung helicopter loads.
Flat top barges can be used as helipads.
Fuel barges can be used for bringing bulk diesel and aircraft fuel into the operating area (no reliable local supply, or carried along the coast/river if there is poor access by road) and then kept as floating storage.
The most useful sizes of flat top barge for drilling operations are ca. 240 ft x 80 ft or 180 ft x 60 ft. A land drilling rig will fit on the larger size, excluding service companies equipment and camp.
Stand-by vessels
A stand-by vessel, in case of emergency, should be attached to each offshore drilling unit from spud until abandonment. A list of such vessel duties and equipment that should be available is given in appendix x.
In practice it is possible to have two vessels and alternate their function between supply and stand-by, as long as both are equipped for both functions.
Even if a dedicated stand-by vessel is used, at least one of the supply vessels should be equipped as a stand-by vessel so that it can take over the latter's duties in case of breakdown or departure from location (maintenance, bunkering, crew change, etc).
Shallow draft tugs
Shallow draft tugs are mostly required for river work, and are usually "pusher" tugs so that they can get barges into the bank, or onto a gently sloping beach.
They are usually not classed for ocean crossings. However if they are required, and nothing is available locally, then it may be possible to piggy-back them on barges with the other equipment, depending on the crane capacity which will be available. An alternative is to have one towed into the area (with all its openings and hatches covered and welded up for the passage).
It should be borne in mind that typical shallow draft tugs and their crews are not accustomed to high operating standards.
Sea-trucks (Rotorks)
Small landing-craft-type vehicles are available which may be very convenient for river and lake work. These have a draft of 50 cm, a length of ca. 6 m. and a capacity of ca. 3 tonnes or 20 pax, with a speed of ca. 20 knots. They can be obtained with Schottel units or water-jet propulsion.
Ferries
Ferries can be necessary for some operations, although their use adds complication and should preferably be avoided. They may be used for crossing a river if there are no bridges or shallow spots where it can be forded. They can also be a cheap option for moving along a river, or across a lake, if the alternative is to construct a road.
Possible disadvantages are:
- - The relative difficulty of getting a ferry overland to its site.
- - The supervision of an isolated group of rather junior local staff in a remote location (radio links are essential).
- - It is a very attractive facility for third parties, which will inevitably lead to the lose-lose situation of either upsetting the local residents or providing a public service (including unlimited fuel, increased maintenance and, not least, insurance problems).
- - Related to the above, it is an attractive facility for appropriation by local, national or military authorities.
Light craft
Small boats, especially those with outboard engines, are hazardous vehicles and if their use is necessary there should be a heavy emphasis on safety and strict discipline should be enforced.
They should have dedicated drivers and there should be a well-enforced system of journey management with no night-time use.
If outboard engines are used, they should preferably use diesel fuel. Note that it is also possible to obtain outboard engines which run on aircraft fuel (kerosene).
3 Amphibious craft
Hovercrafts are a very effective method of transportation when an amphibious mode of transport is required. They can operate over swamps, mud flats, fast flowing rivers and rapids, deserts, ice and snow fields. They can operate from the equator to the Arctic and from sea level to high altitudes, (up to 5,000 metres). They can operate during periods of poor visibility which would stop other modes of transport like aircraft. They have good transit speeds in the range of 25 to 50 knots (i.e. 46 to 92 km per hour). They are highly manoeuvrable and can operate in an "overloaded state" (within manufacturers recommendations).
They are relatively cheap and simple to operate and maintain. They are significantly cheaper to operate than fixed wing aircraft or helicopters. Their costs are similar to a work boat (not a supply vessel).
They offer a variety of payloads from 1 ton to 70 tons, although higher capacities may be available up to 200 Tons.
They cause minimal environmental damage and avoid the need to construct roads or bridges. They have a very low pressure footprint of ca. 2.4 kpa (50 lbs per sq. ft.), and tend to "float" over vegetation. Small to medium size craft are relatively quiet and wild life get used to them quickly. The larger sized hovercraft can operate onto and off beaches and in moderate sea states. They can climb moderate angles of slope (3 to 5 degrees) and some craft can even climb 7 degree slopes.
They can be used in a variety of roles, i.e. seismic operations, rig moves, crew changes, emergency missions (medevacs and medrescue), ice breaking on rivers, oil spill control. They can operate in day and night conditions. They can be used to carry freight, vehicles or passengers. They can even operate in a combination role. They operate best in regions of limited infrastructure that are of an open nature that is relatively flat, i.e. deserts, rivers and tundra regions.
4 Air transport
Company specialists must be consulted at a very early stage if there is any consideration being given to the use of aircraft to support the operation.
Support for operations on land
Three alternatives should be considered. The most economical solution will depend on the distances and terrains, and on whether airstrips are already in existence or have to be constructed:
- Operate a fixed wing aircraft based at the international airport to an airstrip in the vicinity of the drilling location.
- Operate a helicopter based at the international airport, flying direct to the drilling location.
·Utilise a fixed wing airstrip at a convenient location in the operating area (e.g. materials base) with a crew-car or a helicopter shuttle from there to the drilling location. If an helicopter is used, if should be based at the materials base or at the rig depending on the facilities available.
Air support may also be required during the access road and location construction phase, although the number of people involved will be much less than during the drilling phase.
It is strongly recommended to have a waiting room available at the base airport for the exclusive use of company personnel . This will also serve as an office for the flight co-ordinator/meet and greet man.
Fixed wing
Fixed wing support may be provided by the National Carrier, local charter company or an international contractor. The available options are either an exclusive contract, a "call-off "contract or ad-hoc, with the choice depending on the estimated number of hours to be flown.
Helicopters
In most third world countries helicopter support will be provided by a dedicated aircraft and crew, provided by an international contractor.
If international aviation contractors are used most countries require the contractor to form a joint services company with a local company. This joint venture may take some time to be formed and it is important that invitations to tender are issued at least 6 months before aircraft are needed.
When choosing the helicopter base, consider early morning ground mist, which will prevent helicopters from landing, although take offs may still be allowed. Medivac operations will suffer less delay if the aircraft is based in the vicinity of the rig.
If helicopter crews are confined to the rig site in a remote location with irregular flying activity, individuals can become bored. This should be discussed with the chief pilot so that many subsidiary duties can be given to the crew.
Transport of dangerous goods
Guidelines for the transport of dangerous goods (explosive and radioactive material) will belong to service contractors who should be well aware of the relevant regulations and have appropriate containers, handling equipment etc. Their operating procedures should be checked and compliance included in a technical safety audit.
In principle the requirements for air transport are covered by the ICAO document 9284-AN/905 "Technical Instructions for the Safe Transport of Dangerous Goods by Air". However there is provision within that document for the regulatory authorities of member states to issue dispensations from those requirements.
Materials handling equipment
Materials handling equipment must be regularly checked and maintained like any other pieces of equipment. There must be a replacement back-up for the items which are used frequently and are discarded when no longer safe to use.
Lifting equipment must always be accompanied by valid certificates