DRILLING, PRODUCTION MEET ENVIRONMENTAL CHALLENGE

Guntis Moritis
Drilling/Production Editor

Equipment and practices for extracting, in an environmentally sound manner, hydrocarbons from the earth can significantly differ from one location to the next.

Practices that are environmentally acceptable at one location may place the environment at severe risk at another.

New regulations such the Superfund and Clean Water laws are forcing operators in the U.S. to change the methods for waste disposal or incorporate less hazardous substances into the drilling and production operations.

Two of the most sensitive locations are areas heavily populated or containing ecologically fragile living organisms.

In both of these environments, the monetary cost of exploiting the hydrocarbon resource will be greater because more safeguards are required. But successful projects have been undertaken which met all required environmental standards.

Two recent examples of these undertakings are shown by subsidiary companies of Elf Aquitaine in drilling a well in the city limits of Paris (Fig. 1), and in installing a production platform in the Waddenzee of Holland. (Fig. 2).

DIRECTIONAL DRILLING

In Paris, as in many other populated or agriculturally intensive areas, the well could not be located directly above the target but had to be drilled directionally.

As greater horizontal reach becomes possible through either the use of slant rigs or improved downhole drilling technology, more of these areas can be exploited without detriment or undue interference with residential and other surface uses of the area.

Directional drilling on land is also common in areas such as the harsh environment of the tundra on the North Slope of Alaska.

Minimizing the land area used for well locations prevents excessive harm to the delicate vegetation.

FRAGILE ENVIRONMENTS

One fragile offshore environment that has seen development is the Waddenzee, a Dutch inland water area that is a home to birds, seals, fish, and shellfish. Development was allowed only after very stringent conditions for drilling and production were agreed to.

These requirements included:

No pollution of sea water. Absolutely no drilling fluids, cuttings, wastewater, or rainwater could be dumped into the sea. Everything had to be transported to land for disposal.
A very mild drilling fluid had to be used.
Natural surroundings were to be left untouched.
The unmanned platform had to blend with the surrounding areas. A local architect designed the platform, and the colors were chosen to make the platform a work of art.
Noise was to be reduced.
No helicopters could be used except for emergency.
The lighting could not "dazzle."
The sea bottom was to be disturbed or damaged as little as possible.
The platform was to be fully covered with no piping visible.
Fender piles, 60-in. diameter, had to be set around the platform in case of collisions with vessels or ice.
The jack up rig needed about $2 million worth modifications. These included making the rig completely water tight.
Self-contained water cooling systems had to be installed for the engines. No sea water could be used.
Dredging and antiscouring protection was necessary for the rig.

U.S. REGULATIONS

One recent focus in the U.S. has been on regulations for handling and disposing of wastes generated during drilling and production operations. Most wastes from the drilling and production operation are exempt from the Resource Conservation and Recovery Act (RCRA) Subtitle C that deals with disposal of hazardous substances. But even when labeled nonhazardous, these wastes can still be under the less stringent Subtitle D that is primarily under state control.

Exempt from Subtitle C, and considered nonhazardous, are such wastes as produced water, drilling mud and cuttings, reserve pit waste, and rig wash down water.

Regulated by Subtitle C are such items as used hydraulic fluids, painting wastes, used equipment lube oils, unused frac fluids or acids, radioactive-tracer wastes, and waste solvents.

To comply with these regulations the industry is reducing the amount of waste generated, recycling materials for reuse, treating wastes to eliminate the toxicity, and ensuring proper disposal if nothing else can be done.

One way to lower the volume of hazardous wastes is to eliminate mixing such wastes with those designated nonhazardous. If small amounts of hazardous wastes find their way into a large volume of nonhazardous substances, the entire volume is designated as hazardous.

Recycling and reconditioning used drilling muds, chemicals, and oils is another alternative to reduce the amount of waste. A substance becomes a waste under the regulations only when designated a waste. If it is to be reused, it is not a waste.

Treatment of wastes can involve land farming, biodegradation, incineration, and solidification.

Disposing of wastes in an outside facility does not eliminate liability of the waste producer in cases where the outside facility is not complying with regulatory requirements.

Overlapping RCRA are:

Superfund Amendment and Reauthorization Act of 1986 (Sara Title III) that sets up a reporting system to allow local communities to know the hazardous substances that are being used or stored at a facility.
Hazard Communications Act that requires workers to be informed about the hazards of any material at the facility.
Comprehensive Environmental Response, Compensation, and Liability Act (Cercla) or Superfund laws that regulates the releases of hazardous substances and their clean up and disposal.
Department of Transportation hazardous material rules that regulate shipping of substances.

CLEAN WATER

The U.S. Environmental Protection Agency (EPA), under the Clean Water Act, has been authorized to set the standards and guidelines to control the effluent from drilling and production operations. By volume the two main discharges are the drilling fluids and produced water.

The following guidelines impact the discharges:

Best Practicable Control Technology Currently Available (BPT)
Best Available Technology Economically Achievable (BAT)
Best Conventional Pollutant Control Technology (BCT)
New Source Performance Standards (NSPS).

The BPT allows no free oil to be discharged. The effective date of BPT was July 1, 1977. The BAT, BCT, and NSPS were proposed by the EPA on Aug. 26, 1985, for certain waste streams discharged from offshore facilities. Additional waste streams will be covered by a proposal in 1990, and promulgation of a final rule is planned for 1992.1

Under the National Pollutant Discharge Elimination System (Npdes), issued July 2, 1986, bioassays using small Gulf of Mexico shrimp, Mysidopsis bahia, are required. The toxicity limit of this test is 30,000 ppm suspended particulate phase.

Groups of these organisms are exposed to various concentrations of the test effluent for a predetermined time interval (96 hr for drilling fluid bioassay), and the concentration is calculated at which 50% of the population dies.

The 96-hr LC 50 (lethal concentration at which 50% of the population dies) has been criticized for its variability. Analysis has shown that a toxicity as low as 14,200 ppm is statistically the same as 30,000 ppm.2

For coastal oil and gas extraction only BPT regulations have been promulgated. EPA plans to have BAT, BCT, and NSPS guidelines for these areas by 1995.1

Rules for discharges from stripper wells are under study. Currently stripper oil wells are under the BPT guidelines if in the coastal and agricultural wildlife water use subcategories. For onshore stripper oil wells no rules have been promulgated. Because as many as 450,000 wells fall in the category of producing less than 10 bo/d, these facilities will present a complex administrative task.3

REFERENCES

Federal Register, Vol. 55, No. 1, Jan. 2, 1990, p. 98.
St. John, Barry, "Regulation of the marine oil and gas industry under the clean water act," Petro-safe, Houston, Oct. 3-5, 1989.
Federal Register, Vol. 55, No. 1, Jan. 2, 1990, p. 95.