Mud, brine could finally cap Mexican oil blowout

The Mexican government is close to completing its lengthy and costly attempt to cap Ixtoc I, the oil well blowout in the Gulf of Mexico that has become the world's worst spill.

That is potentially good news to Texans, who worry that if the well is not capped soon, oil will again threaten this state's beaches when ocean currents switch to the north some time this spring. Ixtoc oil stained Texas beaches last summer.

Whether or not the capping effort succeeds, US sources familiar with the operation say, will be known in a matter of weeks, or even days, barring unforeseen developments.

Shortly after the offshore well began spilling oil (June 3, 1979), the Mexican state oil company, Pemex, began drilling two relief wells. The plan was to eventually inject a heavy "mud" substance into the relief wells, which would migrate through the underground rock formation and plug the spilling well. That well would then be sealed with cement.

The first relief well was completed late last year and has helped slow the flow of spilling oil. But it has not been able to provide enough pressure to cap Ixtoc I. What has happened, say experts who have been following the project closely, is that much of the fluid being pumped down the first relief well is being lost in the information, which is very porous.

Now, the second well has been completed, and cementing operations should soon follow.

"The trouble has been that it is a very difficult formation," says Dr. Carl Oppenheimer, a marine biologist at the University of Texas Marine Science Institute at Port Aransas, Dr. Oppenheimer, who visited the well site last month , said Mexican officials told him the formation is more porous than anyone expected, and so fluids injected through the relief wells tend to dissipate and not flow directly into Ixtoc I. This made it impossible for the first relief well to provide enough pressure with the fluids to counteract the natural pressure of the spilling oil.

Dr. Oppenheimer speculates that the success of the second relief well in capping the blowout should be known soon. However, he notes that weather conditions in the gulf are unpredictable and already have delayed the operation.

Injecting sea water and brine into the second relief well -- the step before cement is pumped into it -- already has noticeably reduced the flow of oil and natural gas, says US Cost Guard Capt. Gerald Hinson, on-scene coordinator for the US government's oil-spill response team in Corpus Christi, Texas.

Captain Hinson says an overflight Feb. 13 revealed a significantly smaller slick.

Pemex has estimated the well now is spilling 2,000 barrels of oil a day, compared with 30,000 barrels daily in the weeks following the blowout.

The Mexicans spill has dumped some 160 million gallons of oil into the sea, according to the Oil Spill Intelligence Report, making it the largest such disaster on record.

That publication also reports that Pemex has spent more than $70 million on the capping operation.