SAUDIS MAP $450 MILLION GULF SPILL CLEANUP

Saudi Arabia has earmarked about $450 million to clean up Persian Gulf beaches polluted by history's worst oil spills, created during the Persian Gulf crisis.

Details of the proposed cleanup measures were outlined by Saudi environmental officials at a seminar on the environment in Dubai, OPEC News Agency reported. The seminar was sponsored by the Gulf Area Oil Companies Mutual Aid Organization, an environmental cooperative agency set up by Persian Gulf governments.

Meantime, a Saudi government report has outlined early efforts designed to contain the massive oil spills that hit the Saudi coast before oil could contaminate water intakes at the huge desalination plants serving Riyadh and cooling water facilities at Al Jubail.

Had those efforts not been successful, much of the kingdom's infrastructure, including the giant refining/petrochemical complex at Jubail, could have been paralyzed. An article based on that report appeared in OPEC Bulletin.

The huge slicks in the gulf came from a number of sources (OGJ, Feb. 18, p. 25). The biggest part of the spill occurred when Iraqi forces released crude from the Sea Island terminal off Mina al Ahmadi, Kuwait, and the Mina al Bakr terminal off Iraq.

Other crude was spilled when Iraqi artillery hit a storage tank at the Khafji refinery in the early days of the Persian Gulf war and when two Iraqi tankers were hit by allied bombs.

CLEANUP DETAILS

Nizar Ibrahim Tawfiq, vice-president of the Saudi Meteorological and Environmental Protection Administration (MEPA), told the Dubai seminar 644 km of Saudi coastline had been fouled by the oil spill, Opecna reported.

The massive cleanup effort will focus on 150 sites and take 15-20 months to complete, Tawfiq said. He estimated onshore contamination at the 150 sites at 1.7 million bbl of oil mixed with sand.

The Saudis will give priority to sensitive areas, such as salt marshes and mangroves that are home for many species of wildlife.

Plans call for use of a low pressure water flushing system for mangroves and deployment of small teams of workers to manually remove oil from salt marshes.

On sandy beaches, equipment will separate oil from sand and fresh sand will be brought in.

SPILL ESTIMATES

Tawfiq cited the latest estimate of the volume of oil spilled into the gulf at 11 million bbl. About 24% of the total spill volume, or 1.4 million bbl, has been recovered from the water, Tawfiq said.

His department estimated 30-40% of the spilled oil evaporated.

That leaves slightly more than 5 million bbl of oil to contend with.

So far, no action has been taken to clean up oil deposited on the seabed, but Tawfiq said he hopes natural processes will biodegrade it in time.

CLEANUP APPROACHES

The Saudi government will try to make optimum use of available equipment and materials for the cleanup and seek additional supplies, equipment, or contractor assistance on the international market if needed.

The Saudis have asked the U.S. government for assistance in studies, data collection, and sampling.

Marine recovery by vessels operated by Saudi Aramco Oil Co. have been hampered by varying depths of spill contaminated water, Tawfiq said.

Another problem is how to dispose of oil recovered so far, Tawfiq said, noting the recovered oil is being held in temporary facilities while specialists study options for safe disposal.

CONTAINMENT STRATEGY

A report by the Saudi Royal Commission for Jubail and Yanbu said early spill containment efforts focused on trapping spilled crude before it could drift farther down the coast to Jubail and the desalination plants.

In addition to the commission, participants in the containment operation included MEPA, Saudi Arabian Basic Industries (Sabic)/Petromin Shell, Aramco, and the Research Institute of King Fahd University of Petroleum and Minerals.

The commission provided site management, logistics, and support services in overseeing the project. MEPA provided technical support and hired Tank Cleaning Environmental Techniques, Amsterdam.

Sabic and Petromin Shell hired O'Brien Oil Pollution Systems, Gretna, La., and Aramco hired Martech, another U.S. oil spill specialist, to assist in the operation.

The commission chose Khaleej Mardumah, a small bay north of Jubail, as the ideal site to trap and recover spilled oil because:

• Geographically, it provided a natural trap for crude drifting from the north.

• The nearby island of Ras Abu Ali would deflect oil toward the funnel shaped bay.

• Prevailing northwesterly winds and shoreline currents would drive the oil into Mardumah Bay, depositing it on the shoreline, along the intertidal flats at Al Gurmah, and in nearshore waters.

• The water in the bay, deep enough to allow on-water recovery, is sheltered from high winds and seas.

INITIAL EFFORTS

At the outset of the containment program, free-floating crude was boomed off to guide it to shore and prevent winds and currents from carrying it back to sea.

In Mardumah Bay, north-northwest winds pushed the crude toward shore while south-southwest winds and low tides pulled the crude away from shore. Varying temperatures also affected oil movement. That called for opening, closing, and relocating booms as tides and winds moved the crude around.

After containing the floating crude with booms, it was recovered from the sea surface with skimmers, diaphragm pumps, and dredgers.

The Saudi led team also used tidal oil traps to collect oil. That involved digging rectangular pits equipped with weirs along the shore. The floating oil, driven by tide and wind, was forced to overflow, skimming into the weirs and leaving the water behind. The traps were used in conjunction with sand jetties into the sea that acted as funnels to direct floating crude oil to the pits.

At peak efficiency, determined by optimum conditions of 16 knot north-northwest winds, tides of more than 1.9 m, and temperatures topping 90 F., tidal trap recovery at Mardumah reached as much as 28,000 b/d.

OIL REMOVAL

Key to the operation's productivity was speed in transporting recovered oil from worksites to dumpsites.

That's because skimming and pumping operations otherwise would be hindered by the limited capacity of receiving pits, holding pits, and tidal oil traps.

The support team assembled a fleet of 34 transport units consisting of vacuum trucks, supersuckers, and oil tankers of varying sizes and capacities from a number of government agencies.

Initial problems with high oil viscosities and determining the best fill methods were soon overcome, with productivity reaching a high of 25,120 bbl of oil recovered in a 16 hr shift.

Recovered oil was moved to new temporary dumpsites in the Sabkha area 5 km from the worksites. Each of the dumpsites consisted of five cells constructed from sand berms with a total capacity of 690,800 bbl/dumpsite.

One cell was designated as the unloading cell. Once that cell was full, oil was allowed to overflow into adjoining cells through transfer weirs or gates cut into partition walls. Each cell was lined with polyvinyl chloride and polyethylene liners to prevent oil from leaching into groundwater.

Copyright 1991 Oil & Gas Journal. All Rights Reserved.