Incident
Name: YUM II/Zapoteca
Subject:
USCG Case History
Incident Date:
10/10/1987
Incident Location:
Campeche, Gulf of Mexico
Author:
USCG Case History
Latitude:
18 48 N
Longitude:
092 35 W
USCG District:
8
Product:
Light crude oil
Type: 2
Volume:
58640
Source:Platform
RAR: Commercial fisheries, unforested upland, shrimp.
Dispersants:
No
Bioremediation:
No
In-Situ Burning:
Yes
Special Interest
Topic(s): Closure of commercial fishing areas, interaction with foreign or Native authorities.
Shoreline Type(s)
Impacted: Brackish marshes.
Summary:
On October 10, 1987, the YUM II, a Mexican exploratory oil well located approximately 20 miles northwest of Ciudad del Carmen in the Bay of Campeche under the Zapoteca rig, experienced a blowout and fire. Apparently, a blowout preventer (BOP) valve malfunction caused the initial blowout. Although the BOP had successfully shut the annulus between the drill pipe and well casing, the blind rams failed to shear through the drill pipe that was still in the well casing. Therefore, oil and gas flowed out of the well, up the drill pipe, and onto the platform where it ignited. The oil discharge increased after the escaping gas and oil forced the drill pipe out of the well. The initial fire was extinguished by October 17. As of October 28, the well was still spewing out a yellow gas/crude mix 60-100 feet in the air. The owners of the well, Petroleos Mexicanos (PEMEX), and the Mexican Navy participated in cleanup operations. The well was finally "killed" on November 30.
Even though the incident site was 600 miles from Texas, the slick could have traveled in a northerly direction to reach United States waters depending on the duration of the spill. Accordingly, the USCG Marine Safety Office (MSO) at Corpus Christi, Texas, was notified of the incident on October 13. Verification and correct information were not received until October 16. Even though USCG assistance was refused, the USCG conducted overflights of the area every other day until the well was capped to track the spill response and the movement of the oil. Reports of cleanup activities from the Mexican authorities were infrequent and largely erroneous. Daily reports from the Mexican Embassy to USCG Headquarters in Washington, D.C. were not available when promised.
Behavior:
The rate of oil discharged was believed to be approximately 30,000 barrels per day based on other production rates in the area. Much of this oil probably burned off.
On October 16, patches of crude oil extended out from the well site 7 miles, while rainbow sheen continued out to 14 miles. A USCG October 18 overflight observed a rainbow sheen 250 yards wide extending westerly from the spill site for 55 miles. As of October 22, oil had been spotted 115 miles west of the well and 45 miles north of the furthest western advance. No impact had been observed on the Mexican Coast at this time.
On October 24, streaks of orange-brown mousse extended west from the well for 8-10 nautical miles. A second slick of the same description was observed approximately 95 nautical miles west of the well. Orange-red bands of heavy sheen were observed drifting west out to 25 nautical miles on October 26. A dark colored oil slick extending on the surface 3 miles downwind from the rig was observed as of October 28. Oil was observed impacting approximately 20 miles of Mexican shoreline southwest of the rig. The most heavily impacted beaches were Tabasco and Campeche. Much of this coastline area contained small islands used for cattle grazing.
On November 1, the slick extended approximately 90 miles to the west of the well. Strong northeast winds moved the oil slick slightly to the southwest near November 7. Some oil patches were blown 15 kilometers up the San Pedro River. Fishermen on Nuevo Campechito beach reported a slick 10 kilometers long and 13 centimeters deep. No more oil was spilled into the water after the capping on November 6. As a result, no oil was observed beyond 16 miles of the well on a November 8 overflight.
Mexican officials reported 75 miles of impacted shorelines. The final USCG overflight on December 10 noted light sheen 200 feet wide and scattered patches of oil approximately 9 and 10 miles southwest of the well.
Countermeasures/Mitigation: Although approximately 300-400 feet of boom was deployed at the scene on October 17, the booming was ineffective because cleanup vessels were dragging the boom through the slick to break it up rather than using the boom to contain the oil. \\From October 18-24, the Mexican authorities conducted a controlled burn-off operation. During this burning, 90 percent of the escaping oil probably burned off while 10 percent entered the water. Three firefighting vessels cooled the rig while the oil was allowed to burn. The fire was re-ignited when the engineers did not need to be near the well head in an attempt to keep water pollution to a minimum.\\According to Mexican authorities, most of the oil on the ocean was a gas condensate and was successfully skimmed with two skimmers, one made by Vikoma and the other by Frank Mohn.\\PEMEX used bulldozers to clean oiled beaches. This method was questionable since much of the affected coastline consisted of brackish marshes.
Other Special
Interest(s): The USCG extended an offer of assistance to the Mexican Navy in accordance with the existing bilateral agreement, even though the oil was not projected to impact U.S. waters or land. The Mexican Navy chose not to accept this offer. Communications between the USCG and the Mexican Embassy were not forthcoming. Overflights conducted by the USCG were the primary source of correct information of the progress of the spill response.\\The Mexican Navy ordered fishing cooperatives in Frontera and Barra de San Pedro to keep approximately 300 fishing boats tied up for 25 days. The cooperatives sued PEMEX for 600 million pesos to compensate for lost income.
References:
IFP Platform Databank
U.S. Coast Guard POLREP file.
Last Edit: 9/21/92 |