"Health, Safety and Environment" are the aspects of activities which relate to how work is carried out rather than to what is done. They have been grouped together and must jointly be given equal priority with the technical content of any operation. This is a Group Policy and it is a primary responsibility of the Drilling Supervisor to ensure that all the contractors involved , as well as all staff members, are aware of this policy and are fully committed to it.
What must be recognised is that health, safety and the protection of the environment are the responsibility of line management and are implicit in all operations, and should not be considered separately.
During Production testing the following general guidelines pertaining to safety should apply.
The appropriate authorities should be notified prior to any production testing especially where it is performed near populated areas. The requirement for such notification is often defined by government legislation.
After perforation, the opening of the well to unload the tubing contents and the initial flow through the separator shall be carried out in daylight. Thereafter the production test may continue during hours of darkness.
The production test (onshore/offshore) should only be commenced under the following conditions:
1.All test facilities are fully pressure tested and checked.
2.Wind force and direction suitable to carry gases away from rig.
3.Fire, H 2S and abandon location drills are held.
4.Weather suitable for rescue operations.
5.Shipping and aircraft warned to stand clear during flaring.
6.Standby boat advised that this operation is to take place, and the action and precautions necessary until the operation is completed.
7.Verify that the wellhead and production valve ESD systems function correctly and that emergency shut-down activating buttons are manned in a safe area throughout the test whilst flowing formation fluids to surface. ESD system checks must be auditable and compliance checked for prior to opening up well.
8.Check that all piping unions are properly matched and according to agreed standardised type.
All hot work shall cease during the production test. Cranes should not be used over or near wirelines, flowlines, separators, heater or choke manifold.
Personnel not directly involved with the operation stay well clear of production lines.
Cooling water hoses shall be laid out on the flare side. In the case that the ambient temperature drops significantly below zero, and icing problems are observed to be occurring as a result of the cooling spray, testing operations should be terminated, possibly being restarted using brine as a cooling fluid. Glycol/water mixture and low freezing point hydraulic fluids should be used in all critical lines/systems. Every measure is to be taken to maintain a safe working environment in the testing area.
Aviation fuel tanks and all pressurised bottles shall be located away from radiant heat and cooled, if required.
A close check should be kept on the casing/tubing annulus pressure. If this pressure increases it should be bled off (noting the volume and type of fluid bled off) and the annulus pressure checked for the rate of build-up. If the annulus pressure cannot be bled off the well shall be squeeze killed or reverse killed, depending on circumstances.
Gas explosion meters, hydrogen sulphide detectors and sets of breathing apparatus must be available. Gas must be checked for the presence of hydrogen sulphide. Contingency plans in the event of significant H2S production must be in place.
Equipment and material to fight oil spills should be available on site in the areas where such spills could give rise to a hazardous situation or have detrimental environmental effects.
After production testing all lines containing oil shall be flushed with water, brine or mud prior to disconnecting.
Rig air for production testing over sustained periods may be insufficient to cope with burner requirements. An independent air supply in this case is preferable.
Install non-return valves in air lines to ensure that rig air systems are not contaminated with hydrocarbons. Do not interconnect air/oil/gas lines.
1. Health hazards from exposure to H2S gas
Refer to EP 55000-32 which comprehensively covers the subject. Other non-H2S related health hazards are documented in EP 55000-31.
2. Area classification
2.1 Hazardous atmosphere
This is an atmosphere containing significant quantities of flammable gas or vapour in a concentration capable of ignition.
The term refers exclusively to the danger arising from ignition, but it must be remembered that a dangerous condition also exists where the atmosphere contains toxic gas or vapour in such a concentration as to be a danger to life.
2.2 Hazardous area
This is an area in which a dangerous atmosphere exists. Dangerous areas are classified under three headings, Zone o, Zone 1, and Zone 2, which are defined as:
Zone 0 An area in which a dangerous atmosphere could continuously be present.
Zone 1 An area in which a dangerous atmosphere is likely to occur under abnormal operating conditions.
Zone 2 An area in which a dangerous atmosphere is likely to occur under normal operating conditions.
Well installations, production, separation units, pumping stations, gas compressor stations and similar installations, including well-pulling and other such well-service operations, should be classified as detailed below.
2.2.1 Zone 1 - Areas
1.An open area within a radius of 15 metres (50 ft) from an open discharge or petroleum-bearing fluid or any other point where emission of a dangerous atmosphere is likely to arise.
2.An area within a radius of 15 metres (50 ft) from well-pulling and other such well-servicing operations unless regular tests with an explosimeter show that no dangerous atmosphere is present in which case this area may be classified as Zone 2.
3.Any enclosed premises containing a source of hazard which may give rise to a dangerous atmosphere under normal operating conditions. The extent of the Zone 1 area should comprise the whole of the premises together with the surrounding area within a radius of 15 metres (50 ft) from any point of exit from the building.
2.2.2 Zone 2 - Areas
1.An area within a radius of 7.5 metres (25 ft) of any production plant or other oil process installation in open premises or in the open air, operated as a closed system to prevent in normal circumstances the emission or accumulation in the area of a dangerous atmosphere.
2.Any enclosed premises containing a source of hazard which may give rise to a dangerous atmosphere under abnormal operating conditions. The interior of the building should be classified as Zone 1 but the surrounding area in the open air within a radius of 7.5 metres (25 ft) from any point of exit from the premises may be classified as Zone 2.
3.Any enclosed premises not containing a source of hazard but located in a Zone 2 area should be classified as Zone 1 but if the entry of a dangerous atmosphere is continuously prevented by the provision of fire walls, ventilation or other means, the premises may be classified as a safe area. When mechanical ventilation is employed and it is not possible to guarantee the source and reliability of a safe atmosphere, the premises should be classified as Zone 2.
2.2.3 Vertical extent of Zone 1 and Zone 1 areas
In the naturally well-ventilated conditions of operation on offshore wellhead structures, the vertical extent of the dangerous area above the highest source of hazard may be reduced to 3 metres (10 ft) over the whole of the classified area. Below the source of hazard, the dangerous area extends down to the surface of the water unless there are effective means of preventing the movement or accumulation of oil or gas.
If lighter-than-air gas is released, due consideration must be given to the vertical extent if there is an obstruction to gas dispersal (such as an heliport deck).
3. Pressure testing
Before installation all equipment must be satisfactorily pressure tested to the maximum allowable working pressure in accordance with API spec 6A Appendix F. The following are particularly important:
1.The X-mas tree should be pressure-tested on site. Each valve of the X-mas tree and the check valve should be tested individually.
2.The steamlines to the heat exchanger of the test equipment should be pressure-tested.
3.The relief valves of the separator should be popped when pressure testing the separator. After the test the data and pop pressure should be painted on the relief valve.
4.The SSTT-tree and lubricator valve should be pressure-tested and function-tested on deck before installation in the well.
4. Preparatory work
Whether the drillpipe should remain in stands in the derrick during the test should be considered. A potential danger with drillpipe in the derrick during production test operations is that, in case of a fire on the drill floor the derrick structure is weakened which may cause drillpipe to fall out of the derrick. a further cause for concern is the movement of drillpipe in periods of high wind. A suitable platform should be available to enable safe working at the level of the X-mas tree.
5. Killing facilities
Adequate killing fluid of the correct gradient should be available. Kill/mud pumps should be connected to the kill mud tanks with a control switch on the rig floor to the pump room. Killing lines from the kill/mud pumps to the Xmas tree/annulus should be as direct as possible. All valves in the killing system should be trimmed and the non-return valve at the Xmas tree checked to ensure it is not leaking. A circulating/kill valve with a suitable tubing thread pin end on bottom should be on the drill-floor throughout the test so that shutting off or circulating the well during pulling the tubing is possible.
6. Hot work
Hot work during production testing operations may only take place when authorised by a "Hot Work Permit", which is signed by both the person in charge of the rig and the Production Operations Engineer. A permit to work system exists for the various facets of rig operations and must be utilised.
7. Perforating - safety regulations
The following safety regulations must be observed during perforating:
1.All personnel non-essential to perforating and production testing should be taken off the rig prior to perforating the well.
2.During any job involving the use of explosives, the number of personnel employed should be kept to a minimum. All other persons should be excluded from the danger area (e.g. walk-way, derrick floor) throughout the operation.
3.Warning signs should be placed on access routes to danger areas.
4.An Abandon Rig, Blow-out and Fire Drill should be held prior to perforating operations.
5.During perforating operations, the fire-fighting system should be under pressure.
6.Work involving the use of explosives should never be done under conditions of thunder, lightning or heavy fog.
7.Welding is not permitted during the period commencing with the arming of the gun and finishing with the confirmation of no misfire after the removal of the gun from the lubricator.
8.Gas explosion meters, hydrogen sulphide detector(s) and portable breathing apparatus sets must be available and operable. As soon as possible well effluents must be checked for the presence of hydrogen sulphide by the Production Operations Engineer or Petroleum Engineer.
9.No helicopter landings can be made from the time the gun is armed until the gun has been pulled and checked or disarmed.
10.The first perforation must be carried out in daylight, but later runs may be carried out at night. However, if in the course of perforating or during subsequent production testing the well has to be killed, the first of any subsequent perforations must also be carried out in daylight.
11.Before the gun is armed all transmitters including the radio beacon (the teleprinter may be left on stand-by), cranes, welding machines, etc. in the immediate vicinity (within a radius of 150 ft) of the wellhead must be switched off and remain switched off until the gun has been pulled, laid down and checked/disarmed. Transmission, crane operations, etc. may be resumed thereafter. Supply boats or other vessels should not be moored to the rig and should be ordered to "standoff" during these operations.
12.Portable transmitters should be placed in one room to prevent accidental transmission.
13.The Petroleum Engineer is to witness the earth testing of equipment. A constant check to ensure that voltage does not exist between the casing and rig at surface must be made. If a voltage is found to exist, all sources of electrical energy must be switched off (this may preclude perforating at night).
14.Before the well is perforated a Safety meeting should be held with the following people present:
-Drilling Supervisor
-Petroleum Engineer
-Rig Drilling Supervisor
-Barge Engineer
-Radio Operator
-Production test contractors
-Perforating contractor.
During this meeting the Company Production Operations Engineer should explain the safety regulations. He should also emphasise responsibilities and outline reporting/communication lines which have to be followed.
15.Two hours before each perforating run the Petroleum Engineer must inform the base about the estimated time of closing down the radio beacon transmitters and other means of communication, and the duration of the shut-down. Actual times will be advised by the radio operator. Helicopter flight control must receive the message of closing down communication in order to postpone any planned flights.
16.The Production Operations Engineer should be on the site during perforating operations. He will ensure that the THP is bled down to zero and that the well is closed in.
8. Chemicals (SHOC)
Reference should be made to Safe Handling of Chemicals which should lists the chemicals commonly used in the petroleum industry and gives details of its composition, health considerations when handling, inhaling, etc.