Cementing, a crucial step in drilling safely for oil or natural gas, is prone to frequent failures such as the one that led to the Deepwater Horizon disaster in the Gulf of Mexico.
That appears to be one of the starkest lessons federal investigators have drawn so far in their probe of the explosion that killed 11 and unleashed the worst offshore oil leak in U.S. history. It is a topic almost certain to be probed at a hearing of the presidential commission investigating the disaster when it next meets, on Nov. 8.
BP PLC, which owned the well and oversaw the drilling, and Halliburton Co., which did the cement job, have been battling publicly over who caused the disaster and how. But they appear to agree that “cementing failures are not uncommon even in the best of circumstances,” as the federal investigators wrote in a letter released Thursday that chided both companies for their performance.
Indeed, one expert suggests that one-fourth of all cement jobs fail to some degree, though such failures rarely lead to catastrophes. “Very rarely are they perfect,” Gene Beck, a petroleum engineering professor at Texas A&M University, said.
Cementing wells is about a $6 billion-a-year business, according to Spears & Associates, a Tulsa-based oil-services market analyst. All oil and natural-gas wells are cemented, from oil wells deep in the Gulf of Mexico to horizontally drilled natural- gas wells in Pennsylvania.
When there are signs of trouble, wells can be tested to make sure the cement sets. With the BP well, the energy company didn’t run a crucial test of cement integrity and misinterpreted another test designed to determine whether the well was leaking.
By highlighting the uncertainties about cement, testing and other parts of the drilling process, the Gulf disaster has shaken public confidence in the industry, said Bruce Bullock, director of the Maguire Energy Institute at Southern Methodist University in Dallas. “When you look at this, the first thing you ask is, ‘Is this more art than science at times?’ ” Mr. Bullock said.
Mr. Bullock said that questions about the industry’s capability will likely color the debate over onshore drilling for shale gas, because many wells are likely to be located near people’s homes.
Indeed, environmental groups seized on the new revelations as evidence that onshore drilling is riskier than the industry lets on.
“Very often what we’re told in meetings with industry and regulators is it’s a tried and true process and you’ll be safe with us,” said Gwen Lachelt, director of the Oil & Gas Accountability Project, an effort by the environmental group Earthworks. “Now to have this come out in such a public way after one of our nation’s worst environmental disasters, it’s cause for concern.”
Facing accusations that its cement job led to the Gulf blowout and oil spill, Halliburton on Thursday did not dispute the federal investigators’ claim that cement jobs often fail. Halliburton, the world’s largest oil-field cementer and holder of many cementing patents, argued instead that it was incumbent on BP to test the well after cementing and make fixes if necessary.
Halliburton, of Houston, has its work cut out for it as it prepares to defend itself in the nearly 350 lawsuits related to the Deepwater Horizon blowout and avoid any cleanup liability. But its defense could hurt the industry’s effort to convince the public it can operate in a safe and environmentally sound manner, some experts say.
“If Halliburton’s point is ‘Gee, sometimes bad stuff happens,’ that is not good for the industry,” said Jason Grumet, president of the Bipartisan Policy Center, a Washington, D.C., group involved in energy policy. “But I’m sure the industry will reject that premise and argue there were specific, preventable problems.”
Bad cement jobs that went undetected have led to offshore blowouts before. A study of incidents between 1992 and 2006 found that cementing was the single largest contributor to Gulf of Mexico blowouts, playing a role in 18 of 39 incidents.
Halliburton has been the cement contractor in some major incidents, such as one off Australia in 2009, when a platform exploded and a well leaked oil for two months after a failed cement job.
Normally, when something goes wrong with cement jobs, the well owner goes back and squeezes more cement into any cracks, fixing the problem. But companies can fix problems only if they detect them.
BP’s internal investigation found that its workers didn’t follow company guidelines for when to perform the tests.
“Everybody who knows anything about drilling wells knows that three things are the most important: cement, cement and cement,” said A. Scott Anderson, senior energy policy adviser at the Environmental Defense Fund. “If the industry expects any meaningful degree of public support, they need to demonstrate that they can do their job whether the circumstances are the best available or the worst.”