This article presents a summary of the main deficiencies encountered in drilling operations

1 Lifting equipment

All equipment used for lifting must have the safe working load clearly marked on it. This essential detail is valid even for consumable items such as slings and shackles. Additionally, lifting equipment should be carefully inspected monthly and thoroughly NDT tested every 12 months (see EP-5500 Section 3433).

It is also necessary to keep a register of all slings and shackles with latest inspection dates on the rig. So that individual slings can be easily identified, each sling should be tagged/marked with its unique identity code. (Similar to a movable number).

Deficiencies

• ·No register of slings and shackles kept on the rig.
• ·Newly purchased slings and shackles are uncertified and are not proof tested.
• ·The SWL is not marked on lifting equipment, e.g. BOP lifting trolleys, air winches.
• ·Pre-slung cargoes are manifested without including the slings - e.g. 'l lot' slings is not adequate.
• ·Damaged and potentially dangerous slings are mixed up with good slings.

2 Weight control

Consignments of materials to and from the rig are commonly loaded onto and from transport vehicles by crane. It is essential that crane drivers, supervisors and rig stability staff know the weight of each lift. Unusually heavy lifts should be done under the permit to work system using certified lifting slings.

Deficiencies

• ·Materials are loaded and consigned with the wrong weight on consignment notes. In some cases the weight is not mentioned at all.
• ·Most material yards have scales for verifying loads. However, this equipment is often not used and load weighs are overestimated instead.
• ·Crane drivers offshore are obliged to pick up loads 'blind' if there is no weight given on the consignment note.
• ·Rig stability calculations are incorrect due to overestimated weighs quoted on consignment notes.

3 Fork-lift trucks

Most palletised materials are handled with fork-lift trucks. The truck used should be suitable for working in hazardous Zone 2 areas or the permit system is required for work in a classified area. There are many instances of accidents associated with fork-lift trucks and they are usually caused by one or more of the deficiencies listed below.

Drivers of fork-lift trucks should always be experienced and verified competent. To avoid unauthorised drivers 'having a go', there must be a visible list of authorised drivers on the notice board with published rules stating clearly that persons not on the authorised list may not use the vehicle for any purpose.

A reversing alarm should be fitted to the vehicle though care should be taken to select equipment suitable for hazardous Zone 2 area classification.

Deficiencies

• ·The fork-lift truck is unsuitable for hazardous area Zone 2 use (e.g. electric starter motor with battery).
• ·Reversing alarm not fitted.
• ·Unauthorised persons driving the vehicle (e.g. the contract mud technician).
• ·List of authorised drivers not published and visible.
• ·The fork-lift is used for lifting personnel.

4 Chemicals

At any time on a rig there are a large variety of chemicals which are used for:

• ·drilling muds;
• ·completion fluids;
• ·formation stimulation;
• ·cement slurry additives;
• ·maintenance solvents and cleaning fluids;
• ·water treatment agents.

As many chemicals are harmful if used incorrectly, it is clearly a requirement that data sheets are available for all chemicals on site. Such data sheets should also be available at the material/transport yard, to any contractor handling the chemicals, and to any driver or supply vessel captain transporting chemical to and from the rig.

Chemical data sheets should include all relevant properties of each substance, the known hazards, e.g. harmful vapours, inflammability First aid and subsequent medical attention recommended in the event of contact with the chemical should also be stated on the data sheet. Personnel handling and transporting hazardous chemicals should be fully informed and should be aware of first aid treatment necessary in case of an accident.

The use of protective equipment when handling and mixing chemicals should be mandatory with provision of deluge shower and eye wash facilities easily accessible. High corrosive, toxic and flammable chemicals must be kept separate and identified with suitable warning signs. Oxidising agents (e.g. potassium dichromate) must be kept away from any form of combustible material (e.g. grease). In areas where local labour may be of particularly low educational standards and with no industrial background, it is often better to prohibit local labour from handling particularly dangerous chemicals (e.g. caustic soda). It is almost impossible to explain to an uneducated person what a caustic or corrosive chemical is.

Deficiencies

• ·Data sheets on all chemicals stored or in use are not available.
• ·The rig medic does not have a copy of chemical data sheets.
• ·Eye wash and douche facilities are not available in the mud mixing area.
• ·Mud mixing crews are not warned of the hazards of particularly dangerous chemicals, e.g. caustic soda, soda ash.
• ·The use of protective equipment is not enforced.
• ·Little is done about significant residues of chemicals left in 'empty' sacks and drums.
• ·Information concerning chemical hazards is almost always lacking during transport.

5 Hazardous area classification

The control of sources of ignition in areas around sources of hydrocarbon emission is vital for the purpose of protection against fire or explosion. Close control of hot work within hazardous area is also mandatory. There are a number of hazardous area classification systems, the one most applicable being the I.P Model Code of Safe Practice (Drilling and Production) and the minimum standard which should be adhered to.

Deficiencies

• ·Hazardous area drawings are generally not available.
• ·The local rules and standards applicable to hazardous area classification are not known to supervisory personnel on site.
• ·Trucks unsuitable for operating in a hazardous zone enter the location without the permission of the Company drilling supervisor. The permit system is not used.

6 Mud-gas separators

The minimum recommended dimensions for a mud-gas separator is given in Pressure control manual for drilling and workover operations. The most significant hazard with this equipment is the possibility of gas venting via the mud line to the rig mud tank and shale shaker area - there being usually no provision in the design of the mud gas separator to prevent this.

It is essential therefore that details of the design of the separator are scrutinised to verify that there is a mechanism to prevent gas escape via the mud line. In the past, serious injury has resulted from hydrocarbon ases entering the shale shaker area - a problem even more lethal if H 2S is involved.

Deficiencies

• ·Inadequately designed mud-gas separator.
• ·Drawings and specifications for the separator are not available.
• ·Overall separator dimensions are below the sizes recommended in Pressure control manual for drilling and workover operations.

7 Gas cylinders

Gas cylinders are used and stored on all drilling locations. In the industrialised world the rules for handling and using gas cylinders are well known. In some remote areas, codes of practice and standards applied to the use of gas cylinders may be inadequate and it is under such conditions that special attention must be paid to the standards of local welders and local suppliers of compressed gases and gas cylinders.

Deficiencies

• ·Oxygen cylinders are stored together with acethylene cylinders.
• ·Cylinders are not kept upright in a shaded area.
• ·Caps of bottles are missing
• ·Full and empty bottles are mixed.
• ·Bottles are wrongly colour coded.

8 ESD systems

• Emergency shut-down systems are generally used to isolate all power from hazardous areas including the drill floor, mud pits and slush pumps. The system is normally function-tested once per well or per rig-up.
• Toolpushers, drillers and assistant drillers must all know the location and function of the ESD actuator situated in the immediate vicinity of the drawworks.

Deficiencies

• ·Most supervisory staff on the rig, including drillers do not know exactly what happens when the ESD function is actuated.
• ·There are rarely any documents anywhere describing ESD procedures.
• ·ESD systems should include isolation of AC power to the rig floor and derrick area.

9 Alarm systems

The same can be observed with alarm systems as with ESD systems. Although the major fire and muster alarms are generally known through drills, the many other alarms such as gas, H2S, Halon release, etc.) are not always known or understood. It is essential that new-comes and visitors are initially trained t recognise alarms and know the required response. It is especially important that all staff on a drilling installation are fully aware of the functioning of all types of alarm.

Deficiencies

• ·Key staff do not know all the different alarms or what they mean.
• ·Crews, contractors and sub-contractors do not know sound of all alarms or the response required.
• ·Alarm systems often conflict, e.g. PA system used for alarm signal but must be used to give directions at the same time.
• ·Visitors and new saff are not briefed on the alar signals used on site.

10 Radioactive sources

For wireline logging operations radioactive source have to be used. Radioactive materials are therefore often stored on or close to the drilling location. Levels of radioactivity around the storage area should be carefully monitored and verified to be within acceptable levels (see EP 55000 Section 3441), and warning signs used to control access.

It is also necessary that a register available of radioactive substances is kept on the rig and updated when there are any changes to the radioactive source inventory. Updated copies of the registe should be forwarded to the senior operations engineer.

Deficiencies

• ·There is no register available giving a description of radioactive sources on the location.
• ·The level of radioactivity around the storage box is not known, either above or below SSC acceptable limits.
• ·No signs warning of radioactivity.
• ·No boundary fence to indicate a no-go area.

11 Radio silence

The procedure for radio silence whilst connecting and handling armed explosive devices is fully described and documented in EP 55000. The need for radio silence is well-known and all radios must be accounted for including portable radios.

In addition DC power should be isolated along with any welding sets or transformers. Such equipment must be electrically disabled and a clearly visible notice attached to prohibit use. It is important to eliminate all potential sources of stray current around the rig floor area, this includes electrically driven cathodic protection systems.

Other sources of radio transmission must be warned in adequate time before operations with electrically detonated explosives commence, e.g. helicopters, police, militia, etc.

Deficiencies

• ·There is no register of portable radio transmitters on the location.
• ·Notices to indicate isolated equipment not in use.
• ·DC power isolation sometimes omitted.

12 Electrical earthing

Proper earthing of electrical equipment and drilling equipment throughout the mud system is important. Without an effective earth, dangerous potentials could build up and result in electrical discharge in areas classified as hazardous. Such a potential source of ignition can be eliminated by interconnecting all tanks and mud mixing systems and ensuring that resistance to earth is low (< 1 ohm). Sensitive equipment such as computer, instrument logic boards and digital recorders can also be adversely affected by poor earthing. Concern on these problems is usually restricted to dry desert environments.

Deficiencies

• ·Mud tanks and mixing skids are not interconnected or earthed.
• ·The quality of earth is not checked with a Mega insulation tester.