RIG SAFETY DEPENDS ON EQUIPMENT, REGULATIONS, AND PERSONNEL

Thomas R. Bates Jr., Stuart Tait
Sedco Forex
Aberdeen, U.K.

Galin Mumford
Sedco Forex
Montrouge, France

Improvements that can increase rig safety can be made in equipment, regulations, and stabilized personnel levels.

With regard to equipment, exposure to material handling must be reduced through automation, and well-control technology must be improved by enhanced use of computers and better systems to handle gas.

Regulations are needed that are global in scope and have had their costs-to-benefits fully and fairly assessed. Self regulation must be used effectively throughout the industry. Job security and wages should be made adequate to maintain an experienced, motivated, and safe work force. All these issues can be addressed more effectively if term contracts are the rule. It is important for the industry to be able to make long-term commitments to its employees to ensure a safe future.

CONTRACTORS

Much has been written about offshore safety in the months since the tragic disaster on Piper Alpha in mid-1988. For the most part, this discussion has focussed on the operation of fixed production platforms. Mobile offshore drilling rigs represent an important part of the offshore environment.

Although the emphasis in this discussion is placed on the drilling contractor's role in the offshore industry, it is thought that these issues are relevant to many offshore contractors regardless of their particular business.

To a large degree, this will feature a North Sea orientation with the issues of heavy weather, a complex regulatory environment, latest generation technology, and a highly skilled and well trained work force.

The importance of contractors in the offshore environment is not always apparent. The makeup of the offshore work force in the North Sea is shown in Fig. 1. Surprisingly, only 23% of all offshore workers are oil company employees.1 Fully 22% are drilling contractor employees with the balance representing other contractors.

As further evidence of the role that contractors play, more than 50% of the offshore installations registered with the U.K. Department of Energy (including platforms, rigs, construction barges, etc.) are owned and operated by contractors.

Contractors are utilized in the offshore environment to drill, test, construct, dive, repair, maintain, feed, clothe, and house.

Any comprehensive discussion of offshore safety must include the role of contractors and their personnel.

Offshore safety is a complex issue. In the discussions which follow, the roles of equipment, regulations and, most importantly, personnel, will be identified with respect to safety on offshore drilling rigs.

EQUIPMENT

The data in Fig. 2 show rig-loss accident statistics2 from 1956 to the present. The percentage of the fleet lost through accidents of all types has decreased significantly. In the early history of the offshore industry, nearly 2% of the rig fleet was lost each year.

Today, that figure has improved by a factor of five to less than 0.5%. In the decade of the 1980s, the rate of rig-loss accidents from all causes other than blowouts has declined by 80%. Offshore drilling rigs meet acceptable structural and stability design criteria and are unlikely to see significant changes in the near future.

There have been many improvements in the drilling equipment used on offshore rigs. Mechanization has been introduced on the drill floor. Man-riding winches have replaced catlines. Load-limiting devices have made cranes much safer. However, much work remains to be done to improve the work environment.

The drill floor and the pipe deck are still the most dangerous areas of the rig, as seen in Fig. 3. With the economic state of the industry today research and development has virtually stopped, and little progress can be anticipated in the next 2 or 3 years.

The next generation of drilling rigs will make a quantum leap forward in automation of the workplace. Enhanced automation and the use of robotics is anticipated to eliminate the need to expose roughnecks and roustabouts to many material-handling activities.

Fig. 4 shows an automated pipe-handling system for a 1990s generation rig. All tubulars are stored in a central caisson and can be handled without any human contact.

Fig. 5 shows the mud-handling system on that same 1990s rig.

All mud chemicals can be added to the system using automated bulk and liquid additive systems requiring no human intervention.

The exposure of rig crews to material-handling risks must be reduced in order to continue the present trend of improvements in personal injury safety performance.

Another aspect of equipment technology which impacts drilling-rig safety is well control. Rig-loss accidents caused by blowouts actually increased2 (after normalization for rig activity) in the decade of the 1980s. During 1956-80, the frequency was 18% and increased to 23.6% for the years 1981-88. Improvements must be made in well-control systems and in information-management systems related to well control.

History shows that shallow gas presents serious problems for the industry. Over 50% of all incidents involving diversion of shallow gas have resulted in failure of the diverter system.3 Yet today, there is not a universally acceptable set of design criteria to use for diverter systems.

Recent incidents on the UKCS have highlighted the problems of drilling deep, high-pressure gas wells.4 It appears that well-control systems could be exposed to a combination of pressures and temperatures for which they have not been designed. An urgent review is in progress in the U.K. concerning both of these issues.

Computers are used today to record drilling information; predict pore pressures; keep track of inventories; make mooring, load, and stability calculations; and keep dynamically positioned vessels on location. In many ways these information systems have bypassed the most important man on the rig in well-control situations-the driller.

Fig. 6 shows a new computer system being developed for use exclusively by drillers. With improved data available at the drill floor for use by trained drillers, better well-control response is expected. After all it is the driller, not the company man or the mud logger, who must make that critical decision to shut in the well in the time span of only a few seconds-often without complete and accurate information available.

Eventually, these information management systems must have the capability to use artificial intelligence to improve the ability to recognize well-control problems. This industry must also begin to utilize process-control technology to further improve response time in well-control situations.

Many operations, including shut-in of the annular, spacing out the tool joint, closing the rams, and controlling the choke, can and should be controlled by computer.

REGULATIONS

The regulatory environment affecting drilling rigs has evolved over the past 40 years.

In the early days, drilling rigs operated largely under rules designed for ships. Now, they operate under a series of rules which have been written specifically for mobile offshore drilling rigs.

Stability and structural rules are much improved. The safety record, as shown in Fig. 2, indicates that regulations for design and construction are relevant and effective in improving safety.

Current regulations are the result of cooperative developments between contractors and operators. This is truly a form of self regulation. Industry must continue to self-regulate effectively or else there will be increasing government intervention.

Government regulation in the drilling industry usually arises after highly visible problems.

A pro-active role can be maintained by following these important guidelines for developing cost effective and safety efficient regulations:

Regulations affecting offshore drilling rigs must be reviewed in a global context whenever possible. New regulations cannot be parochial but should be based, for example, on the 1989 IMO MODU code.
This code has been carefully reviewed by contractors, operators, and regulatory authorities. This will provide a common set of rules for drilling contractors all over the world.
Cost benefit analyses should be compiled based on sound risk assessment prior to issuing new regulations. All organizations, including drilling contractors, tend to be reactionary.
With limited resources, the industry must ensure that the investments which are made actually improve safety by the greatest possible margin.
The safety consequences of new regulations must be evaluated. Every new regulation that requires rig modification will cause more accidents.
A simple rig modification which requires 10,000 man-hr/rig will result in another 200-250 lost time injuries if implemented in the entire off shore fleet. The cure must not be more painful than the disease.
Self-regulation must be timely. Needs should be anticipated wherever possible, and the industry must react quickly when there are problems.

Today in the North Sea, drilling contractors are dealing with issues such as shallow gas and diverters, high-pressure, high-temperature wells, and mud chemical exposure. Operators are looking at emergency shut down valves (ESV's), platform evacuation and fire fighting equipment, and permit-to-work systems. The lessons learned in any province must be adopted quickly throughout the entire industry in other geographic regions.

PERSONNEL

The most important piece of the safety equation is people.

Fig. 7 shows that over the last 27 years, the rate of lost-time accidents on drilling rigs has fallen by 77%.5 These improvements have resulted from a combination of factors including:

Better equipment
Improved procedures
Reinforcement of commitment to safety by operators and contractors alike
Regulations designed specifically for the offshore environment
Higher wages and better recruitment
Job security
Drug and alcohol abuse screening
Expanded training requirements.

Unfortunately, the trend of continuing improvement in safety performance is showing signs of weakness.

In 1988, lost-time accident frequency in the North Sea increased (Fig. 8). Effectively, this reversed all of the gains accomplished over the previous 4 years.

The North Sea work force was pushed to the limit, as the number of active drilling rigs on the UKCS increased from 21 to 56. Inexperience is a fact of life in the roughneck and roustabout positions. The number of accidents is concentrated in these job categories as shown in Fig. 9.

The current economic climate has a pronounced affect on employee motivation, morale, and ultimately safety. A majority of offshore workers is affected by the stress of an uncertain employment.

In addition to being affected by the instability of a job that is based on well-to-well contracts, there has been a significant deterioration in earning power among offshore workers.

Fig. 10 shows the relationship of wages in the North Sea for roughnecks and roustabouts compared to the average wage paid for onshore labor through 1988. There has been an erosion of the premium paid for offshore work.

The combination of erosion in wages and job instability has created higher-than-desired turnover. Fortunately, during 1989 there has been a significant increase in wages paid to nonsupervisory employees, which should act to reduce attrition.

Substance abuse, including both alcohol and drug problems, is becoming more and more prominent in society. Random testing, and routine testing as a part of a continual medical surveillance, has shown that it has already begun to creep into the offshore work force in the North Sea.

The failure rate for preemployment drug testing of "new hires" is nearly one in ten. Personnel offshore will have to be made aware of the dangers which arise both offshore and onshore. All offshore employers will need to adopt pro-active programs to eliminate substance abuse in the offshore population.

Training requirements are still high. Many contractors and operators have increased their training requirements even through the dismal economic period of the latter half of the 1980s. Sedco Forex training requirements for drillers are extensive.

Unfortunately, experience may be decreasing so fast that additional training cannot keep up. This is particularly true when stacked rigs are picked up for short-term contracts.

So what does the future hold for personnel working offshore? Is it possible that the deterioration in safety results seen in the North Sea in the late 1980s will spread to other areas of the world as the industry expands beyond its capability to provide experienced personnel? If the experience in the North Sea is not to be repeated, these issues must be recognized and addressed by both contractors and operators.

OPERATOR-CONTRACTOR RELATIONS

There can be no doubt that an industry with chronic financial losses over many years will suffer in safety performance. Evidence exists in the airline and coal mining industries to confirm this. No party in the industry is deliberately lax in regard to safety. On the contrary, standards today are higher and rules are tighter than they were 5 years ago.

Unfortunately, the effects of low dayrates on the wage structure within the industry have resulted in job dissatisfaction, high turnover, and lower average experience within the sizable segment of the industry. All of these issues detract from safety.

The solutions to the drilling industry's financial problems are neither obvious nor imminent.

There are steps that can be taken by operators and contractors that will improve safety performance with absolutely no cost. The most important is a commitment to a long term working relationship.

The accident rate on long-term contracts of 4.7 lost time frequency is substantially less than the 22.2 on well-to-well contracts, where attrition and "battlefield promotion" can play such an important role. It is significant to note that efficiency improves on long-term contracts as well.

The well-documented learning curve is illustrated in Fig. 11 with data from a North Sea field.7 If operators can put wells together-even with other operators-so that a rig gets a minimum 12-month commitment, safety performance and drilling efficiency will improve significantly.

Dayrates can be linked to market rates to ensure that the contract is fair to both parties.

This won't cost money. However, it does require planning and it will produce results.

REFERENCE

"Oil and Gas Prospects: 1989 Update," Grampian Regional Council, Aberdeen, July 1989.
"Offshore Mobile Rig Accidents: 1955 to Present," Offshore Data Services Inc., Houston, 1988.
"Diverters Fail in 50 Percent of Gas Blowouts," Offshore Accident Review, Veritec, Oslo, August 1986.
Wann, K.E., "The Ocean Odyssey-Well Control Project," Offshore Europe, September 1989.
"IADC Accident Statistics," IADC, Houston, 1989.
"North Sea IADC Accident Statistics," IADC, Aberdeen, 1989.
Denholm, J.M., "North Sea Development Drilling, Southeast Forties: A Case Study," SPE Drilling Engineering, December 1987.